JP2012002117A - Control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce appropriately torque fluctuation and exhaust of harmful gas, in a control device of an internal combustion engine.SOLUTION: A control device 20 of an internal combustion engine is applied to an internal combustion engine (1) including a supercharger (6) having a turbine (6b) provided in an exhaust passage and a compressor (6a) provided in an intake passage, the compressor including a movable vane mechanism (170) for changing the aperture value of flow passage of intake sent out from a compressor wheel (120) by changing a position of a movable vane (180). The device includes a plurality of kinds of intake air amount correcting means (6m, 70, 80. etc.) correcting the amount of intake air in the internal combustion engine, a first determination means which determines whether to change the aperture value on the basis of an operation state of the internal combustion engine, and a control means (20) that selects, when it is determined that the aperture value is to be changed, any one of the plural kinds of intake air amount correcting means on the basis of an operation state of the internal combustion engine, to correct the amount of intake air by the selected intake air amount correcting means.

Description

  The present invention relates to a technical field of a control device for a compression ignition type internal combustion engine such as a diesel engine.

  As a control device for this type of internal combustion engine, for example, in Patent Document 1 or the like, when switching the opening of a variable diffuser in a turbocharger, a device that controls the opening or closing of an intake valve or an exhaust valve to suppress the occurrence of torque shock Is disclosed.

  Alternatively, as a control device for this type of internal combustion engine, for example, in Patent Document 2, the amount of intake air that decreases due to switching control of the opening of a variable diffuser in a turbocharger is estimated, and this estimated intake An apparatus that suppresses the occurrence of torque shock by increasing the opening of a throttle valve according to the amount of decrease is disclosed.

Japanese Patent Laid-Open No. 07-145734 JP 2006-299923 A

  However, according to Patent Document 1 and the like described above, when the opening degree of the variable diffuser is switched in an operation region where exhaust gas recirculation (EGR) is performed, the degree of exhaust gas purification is reduced. A technical problem arises.

  The present invention has been made in view of the above-described problems, for example, and provides a control device for an internal combustion engine that can appropriately reduce the occurrence of torque fluctuations and appropriately reduce exhaust of harmful gases. Let it be an issue.

  In order to solve the above-described problems, an internal combustion engine control apparatus according to the present invention includes a turbine provided in an exhaust passage and a compressor provided in an intake passage, and the compressor changes a position of a movable vane. And a supercharger provided with a movable vane mechanism capable of changing the throttle amount of the flow path of the intake air sent out from the compressor wheel, and a plurality of types for correcting the intake air amount of the internal combustion engine An intake air amount correcting unit; a first determining unit capable of determining whether or not to change the throttle amount based on an operating state of the internal combustion engine; and when the internal combustion engine is determined to change the throttle amount, On the basis of the operating state, the intake air amount correcting means is selected from any one of the plurality of types of intake air amount correcting means, and the selected one intake air amount correcting means, And a control means for correcting the serial intake air quantity.

  The control apparatus for an internal combustion engine according to the present invention includes a plurality of types of intake air amount correction means for correcting the intake air amount of the internal combustion engine.

  For example, the first determination means that can be configured by a memory, a processor, or the like determines whether or not to change the throttle amount based on the operating state of the internal combustion engine. Here, the operation state of the internal combustion engine according to the present invention means a quantitative and qualitative output state of the internal combustion engine such as an output torque or a rotation speed of the internal combustion engine in acceleration operation, deceleration operation or constant speed operation, for example. To do.

  If it is determined that the throttle amount is to be changed, for example, one of the plural types of intake air amount correction means based on the operating state of the internal combustion engine under the control of a control means that can be configured by a memory, a processor, or the like. An air amount correction unit is selected, and the intake air amount is corrected by the selected one intake air amount correction unit.

  As a result, when changing the throttle amount, the degree of leanness or enrichment of the air-fuel ratio of the intake air compared to the target air-fuel ratio can be effectively reduced. As a result, the degree to which harmful gases are exhausted by leaning or enriching the air-fuel ratio can be effectively reduced. Alternatively, it is possible to effectively suppress fluctuations in the output torque of the engine and to improve the driving operability (so-called drivability) of the driver.

  One aspect of the control device for an internal combustion engine of the present invention further comprises second determination means capable of determining whether or not the operation state of the internal combustion engine is an EGR operation state, and the control means is configured to reduce the throttle amount. If it is determined to be changed, and if it is determined that the operating state is an EGR operating state, the intake air amount of any one of the plurality of types of intake air amount correcting means based on the EGR operating state A correction unit is selected, and the intake air amount is corrected by the selected one intake air amount correction unit.

  According to this aspect, for example, it is determined whether or not the operating state of the internal combustion engine is the EGR operating state by the second determining unit that can be configured by a memory, a processor, or the like. Here, the EGR operating state according to the present invention means an operating state of the internal combustion engine in which exhaust gas recirculation (EGR) is performed. When it is determined that the throttle amount is to be changed, and when it is determined that the operation state is the EGR operation state, a plurality of types of intake air amount correction units are selected based on the EGR operation state under the control of the control unit. Any one intake air amount correcting means is selected, and the intake air amount is corrected by the selected one intake air amount correcting means.

  As a result, when changing the throttle amount and performing EGR, it is possible to effectively reduce the degree to which the air-fuel ratio of the intake air becomes leaner or richer than the target air-fuel ratio.

  In another aspect of the control device for an internal combustion engine of the present invention, the control means corrects the intake air amount by the selected one intake air amount correction means simultaneously with the change of the throttle amount.

  According to this aspect, it is possible to quickly correct the intake air amount when changing the throttle amount. As a result, it is possible to quickly cope with the fact that the air-fuel ratio of the intake air is far from the target air-fuel ratio.

  According to another aspect of the control device for an internal combustion engine of the present invention, as the plurality of types of intake air amount correction means, a variable nozzle capable of changing the rotational speed of the turbine, a change means for changing the throttle amount, At least two of a variable valve mechanism that can change the opening and closing timing of the intake valve and a motor generator that can change the rotational speed of the turbine are provided.

  According to this aspect, the intake air amount can be corrected appropriately and with high accuracy by appropriately changing the supercharging pressure. As a result, the degree to which the air-fuel ratio of the intake air becomes leaner or richer than the target air-fuel ratio can be reduced appropriately and with high accuracy.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

It is the schematic diagram which showed typically the basic composition of the vehicle carrying the control apparatus of the internal combustion engine which concerns on 1st Embodiment. It is sectional drawing of the compressor 6a which concerns on 1st Embodiment. It is the figure which looked at a part of compressor 6a concerning a 1st embodiment from the direction of arrow III of Drawing 2. 3 is a flowchart showing a flow of operations in the control apparatus for an internal combustion engine according to the first embodiment. It is the graph which showed the driving | running state of the engine which concerns on 1st Embodiment with the engine rotational speed and the engine output torque. A change on the time axis of the turbo rotation speed, a change on the time axis of the opening degree of the variable DF, a change on the time axis of the opening degree of the diesel throttle valve 70 in the control device for the internal combustion engine according to the first embodiment, and It is the graph (Drawing 6 (a), Drawing 6 (b), Drawing 6 (c), and Drawing 6 (d)) which showed change on the time axis of the opening of variable nozzle 6v, respectively. It is the graph (FIG. 7 (a) and FIG.7 (b)) which showed the quantitative or qualitative characteristic of the pressure ratio and air flow rate in the compressor 6a which concerns on 1st Embodiment and a comparative example. It is the schematic diagram which showed typically the basic composition of the vehicle carrying the control apparatus of the internal combustion engine which concerns on 2nd Embodiment. 6 is a flowchart showing a flow of operations in the control apparatus for an internal combustion engine according to the second embodiment. It is the schematic diagram which showed typically the basic composition of the vehicle carrying the control apparatus of the internal combustion engine which concerns on 3rd Embodiment. 12 is a flowchart showing a flow of operations in the control apparatus for an internal combustion engine according to the third embodiment. In the control apparatus for an internal combustion engine according to the third embodiment, the change on the time axis of the turbo rotational speed, the change on the time axis of the opening degree of the variable DF, and the change on the time axis of the execution and non-execution of the regeneration are respectively performed. It is the shown graph (FIG. 12 (a), FIG.12 (b), and FIG.12 (c)). It is the schematic diagram which showed typically the basic composition of the vehicle carrying the control apparatus of the internal combustion engine which concerns on 4th Embodiment. It is the flowchart which showed the flow of operation | movement in the control apparatus of the internal combustion engine which concerns on 4th Embodiment. It is the flowchart which showed the flow of operation | movement in the control apparatus of the internal combustion engine which concerns on 5th Embodiment. It is the graph which showed the driving | running state of the engine which concerns on 5th Embodiment with the rotational speed of the engine, and the output torque of the engine. It is the graph (Drawing 17 (a) and Drawing 17 (b)) which showed the quantitative or qualitative characteristic of the pressure ratio and air flow in compressor 6a concerning a 5th embodiment and a comparative example. It is the flowchart which showed the flow of operation | movement in the control apparatus of the internal combustion engine which concerns on 6th Embodiment. It is the flowchart which showed the flow of operation | movement in the control apparatus of the internal combustion engine which concerns on 7th Embodiment. Changes in the time axis of the turbo rotation speed, changes in the time axis of the opening degree of the variable DF, and implementation and non-implementation times of the motor-assisted turbocharging in the control apparatus for an internal combustion engine according to the seventh embodiment It is the graph (Drawing 20 (a), Drawing 20 (b), and Drawing 20 (c)) which showed change on an axis, respectively. It is the flowchart which showed the flow of operation | movement in the control apparatus of the internal combustion engine which concerns on 8th Embodiment. It is the graph which showed the driving | running state of the engine which concerns on 8th Embodiment with the rotational speed of the engine, and the output torque of the engine.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
A control apparatus for an internal combustion engine according to a first embodiment will be described with reference to FIGS. 1 to 7.

(Basic configuration of vehicle)
First, a basic configuration of a vehicle equipped with an internal combustion engine control device according to a first embodiment will be described with reference to FIG. FIG. 1 is a schematic diagram schematically showing the basic configuration of a vehicle equipped with the control device for an internal combustion engine according to the first embodiment. The vehicle equipped with the abnormality determination device for an internal combustion engine according to the present embodiment is a so-called in-line four-cylinder reciprocating internal combustion engine in which four cylinders from # 1 cylinder “1a” to # 4 cylinder are arranged in a line. 1 shows an embodiment applied to a so-called “diesel engine” (hereinafter referred to as “engine 1” as appropriate). The engine 1 is used, for example, as a driving source for driving an automobile, and the driving force generated by the engine 1 is transmitted to wheels through a clutch, a transmission, a differential gear, and a drive shaft, not shown.

  As shown in FIG. 1, the engine 1 includes an electronic throttle valve 2, an AFM (Air Flow Meter) 2a, cylinders # 1 to # 4, an intake passage 3, an intake manifold 3M, an exhaust manifold 4, an intercooler 5, an intake air filter. Air filter 5f, turbocharger 6, compressor 6a, turbine 6b, angle sensor 6s for measuring the angle of the rectifying blades of variable diffuser 6n, and supercharging pressure sensor 7s for measuring the supercharging pressure of the intake system of engine 1 , DPNR (Diesel Particulate-NOx active Reduction system) catalyst 8, exhaust purification unit 9, fuel addition valve 10, EGR passage 11, EGR catalyst 12, EGR cooler 13, EGR valve 14, exhaust throttle valve 15, muffler 16, ECU 20, Injector 30, common rail 31, fuel pump 32, crank angle sensor 3 for measuring engine speed A pressure sensor 40 for measuring the pressure in the cylinder, and the intake air amount adjustment of the throttle valve (so-called diesel throttle valve) is configured to include a 70.

  As shown in FIG. 1, the engine 1 is mounted on a vehicle as a driving power source, and the recirculation system of the engine 1, that is, the so-called EGR (Exhaust Gas Recirculation) system is connected to the cylinders # 1 to # 4. The intake passage 3 and the exhaust passage 4 are connected, and the intake passage 3 includes an air filter 5f for intake air filtration, an intercooler 5, a compressor 6a of the turbocharger 6, and a throttle valve 70 for adjusting the intake air amount. The exhaust passage 4 is provided with a turbine 6b of a turbocharger 6, respectively. An exhaust purification unit 9 including a DPNR catalyst 8 which is an example of a storage reduction type NOx catalyst as an exhaust purification means downstream of the turbine 6b in the exhaust passage 4 and a fuel as a reducing agent upstream of the DPNR catalyst 8 And a fuel addition valve 10 as a fuel addition means for adding. The exhaust passage 4 and the intake passage 3 are connected by an EGR passage 11, and the EGR passage 11 has an EGR catalyst 12, an EGR cooler 13, and an EGR from the upstream side to the downstream side with reference to the flowing direction of the reflux gas. A valve 14 is provided.

  The turbocharger 6 is a turbocharger provided with a variable diffuser 6n, and the pressure of the intake air at the outlet of the compressor 6a can be changed by changing the opening degree of the provided variable diffuser 6n. . The angle sensor 6s measures the opening degree of the variable diffuser 6n. In particular, the variable diffuser 6n changes the opening degree in two stages of the first opening degree and the second opening degree (however, the second opening degree is larger than the first opening degree, and the second opening degree is hereinafter referred to as the second opening degree). The opening is referred to as “opening side opening (to be described later, open position Po)”, and the first opening is referred to as “valve closing side opening (to be described later, closed position Pc)”).

  In addition, although the variable diffuser 6n changed the opening degree in two stages of the first opening degree and the second opening degree, the present embodiment is not limited to this. That is, the variable diffuser 6n may change the opening degree in three or more stages. Alternatively, the variable diffuser 6n may change the opening degree in a stepless manner. That is, the variable diffuser 6n may be configured to change the pressure of the intake air at the outlet of the compressor 6a by changing the angle of the rectifying blades of the provided variable diffuser 6n. In this case, the opening sensor 6s may measure the angle of the rectifying blade of the variable diffuser 6n as the opening of the rectifying blade of the variable diffuser 6n.

  The turbocharger 6 is a variable nozzle turbocharger further provided with a variable nozzle 6v, and the flow passage cross-sectional area of the inlet portion of the turbine 6b is changed by changing the opening of the provided variable nozzle 6v. It is possible to change the pressure of the exhaust gas at the inlet of the turbine 6b. The opening sensor 6vs measures the opening of the variable nozzle 6n. The turbocharger 6, the compressor 6a, and the turbine 6b constitute a specific example of the “supercharger” according to the present invention.

  The opening degree control of the EGR valve may be controlled by the ECU 20 so that a predetermined air-fuel ratio according to the operating state of the engine 1 is obtained.

(Detailed configuration of compressor)
The compressor 6a of the turbocharger 6 will be described with reference to FIGS. FIG. 2 shows a sectional view of the compressor 6a, and FIG. 3 shows a view of a part of the compressor 6a as viewed from the direction of arrow III in FIG. As shown in FIG. 2, the compressor 6 a includes a compressor housing 110 and a compressor wheel 120 accommodated in the compressor housing 110. The compressor housing 110 is provided on the outer periphery of the wheel chamber 130 in which the compressor wheel 120 is disposed, on the outer periphery of the wheel chamber 130, and on the outer periphery of the diffuser unit 140. A spiral scroll chamber 150 communicating with the section 140 is provided. The compressor wheel 120 is attached to one end of a rotating shaft 160 provided to be rotatable around an axis Ax. A turbine wheel (not shown) of the turbine 6b is attached to the other end of the rotating shaft 160. When the turbine wheel is driven by exhaust, this drives the compressor wheel 120.

  A movable vane mechanism 170 is provided in the compressor 6a. The movable vane mechanism 170 has a plurality of diffuser vanes (hereinafter sometimes abbreviated as vanes) 180 disposed in the diffuser section 140, and the plurality of vanes 180 can rotate around a pin 190 serving as a shaft section. And a vane operating mechanism 210 disposed on the back side of the base plate 200. The vane 180 is a well-known airfoil-shaped component that directs the flow of intake air. The intake air sent from the compressor wheel 120 flows between the vanes 180. Therefore, a gap between the vanes 180 becomes an intake air flow path. Each vane 180 is attached to one end of the pin 190 so as to be integrally rotatable. As shown in FIG. 3, the pins 190 are arranged at a constant pitch in the circumferential direction. By rotating the vane 180 around the pins 190, the vane 180 rotates so as to open and close the intake air flow path therebetween. As a result, the throttle amount of the intake air flow path is changed.

  The vane operation mechanism 210 includes an actuator 220 having an output shaft 220a as an output member, and a power transmission mechanism 230 that transmits the power output from the output shaft 220a to each vane 180. The power transmission mechanism 230 includes a drive ring (not shown) that is rotationally driven around the axis Ax by the actuator 220, and the rotational motion of the drive ring is converted into a rotational motion in which each vane 180 rotates about the pin 190. Mechanism. Therefore, detailed description is omitted. The actuator 220 drives each vane 180 between the closed position Pc indicated by the solid line in FIG. 3 and the open position Po indicated by the broken line via the power transmission mechanism 230. The closed position Pc is a position where the gap between the vanes 180 is minimized, and the open position Po is a position where the gap between the vanes 180 is maximized. The actuator 220 is provided with a displacement sensor 220b that outputs a signal corresponding to the displacement of the output shaft 220a. The movable vane mechanism 170 constitutes one specific example of the “movable vane mechanism” according to the present invention.

  The operating state of the engine 1 is controlled by an engine control unit (hereinafter referred to as ECU) 20. The ECU 20 is a computer unit including a microprocessor and peripheral devices such as RAM and ROM necessary for its operation. The ECU 20 controls the electronic throttle valve 2 and the actuator 220 according to a predetermined control program to target the engine 1. Control to the operating state. For example, the ECU 20 controls the operation of the actuator 220 so that the position of each vane 180 is changed to the open position Po as the intake air amount increases. By controlling the operation of the actuator 220 in this way, the ECU 20 functions as the vane control means of the present invention. Further, the ECU 20 controls the electronic throttle valve 2 to the closed side so that the operation state of the engine 1 is switched to the evacuation operation state in which the engine output of the engine 1 is limited when a failure occurs that hinders the operation of the engine 1. To do.

  In addition, the operation of various actuators is controlled by the ECU 20. The ECU 20 has passed through a supercharging pressure sensor 7s that outputs a signal corresponding to the supercharging pressure of the intake system, for example, a crank angle sensor 33 that outputs a signal corresponding to the crankshaft angle of the engine 1, and the exhaust purification unit 9. An exhaust temperature sensor that outputs a signal corresponding to the temperature of the exhaust, an AFM (Air Flow Meter) 2a, and the like are connected. The ECU 20 controls the operating state of the engine 1 with reference to these output signals.

  Although not shown, the ECU 20 is connected with various sensors for determining the operating state of the engine 1. The ECU 20 is connected to the displacement sensor 220b described above. The ECU 20 constitutes one specific example of “control means”, “first determination means”, and “second determination means” according to the present invention.

(Basic vehicle configuration: continued)
Returning again to FIG. The intake system of the engine 1 flows from an air duct for taking in outside air (not shown) to an AFM (Air Flow Meter) 2a, an electronic throttle valve 2 and an intake passage 3, and further from cylinders # 1 to # 4 via an intake port. It is configured to be sucked into the internal combustion chamber. The intake port is provided with an intake valve that opens and closes the intake port. On the other hand, in the exhaust system of the engine 1, exhaust gas is discharged from the combustion chambers in the cylinders # 1 to # 4 to the atmosphere via the exhaust port, the exhaust passage 4 (not shown), the DPNR catalyst 8, and the muffler 16. It is comprised so that.

  The fuel addition valve 10 is provided for adding a fuel upstream of the DPNR 8 to generate a reducing atmosphere necessary for releasing NOx absorbed in the DPNR 8 and for S regeneration of the DPNR 8. The fuel addition operation of the fuel addition valve 10 is controlled by an engine control unit (ECU) 20. The ECU 20 operates the engine 1 by operating various devices such as an injector 30 for injecting fuel into the cylinders # 1 to # 4 and a pressure adjusting valve for the common rail 31 that stores fuel pressure supplied from the fuel pump 32 to the injector 30. It is a well-known computer unit that controls the state. The ECU 20 controls the fuel injection operation of the injector 30 so that the air-fuel ratio given as the mass ratio between the air sucked into the engine 1 and the fuel added from the injector 30 is controlled to be leaner than the stoichiometric air-fuel ratio.

  The DPNR catalyst 8 stores nitrogen oxides (NOx) when the exhaust air-fuel ratio is leaner than the stoichiometric air-fuel ratio, and stores NOx when the exhaust air-fuel ratio is richer than the stoichiometric air-fuel ratio or the stoichiometric air-fuel ratio. Is released and reduced to nitrogen (N2). Since there is an upper limit on the amount of NOx that can be stored in the DPNR catalyst 8, NOx reduction is performed at predetermined intervals to release NOx from the catalyst 14 and reduce it to N2 so that the stored NOx amount does not reach this upper limit. The exhaust purification performance of the DPNR catalyst 8 is maintained in a high state. The DPNR catalyst 8 is poisoned by sulfur oxide (SOx) contained in the exhaust gas. Therefore, the DPNR catalyst 8 is heated to a temperature range in which sulfur (S) is released from the NOx catalyst, and the exhaust air-fuel ratio is made richer than the stoichiometric air-fuel ratio or the stoichiometric air-fuel ratio to recover the sulfur poisoning to thereby recover the DPNR catalyst 8. S reproduction for reproducing the function is performed at predetermined intervals. Hereinafter, NOx reduction and S regeneration may be collectively referred to as function regeneration processing. These function regeneration processes are performed by adding fuel from the fuel addition valve 10 into the exhaust passage 4 upstream of the DPNR catalyst 8.

  In the present invention, the NOx storage reduction catalyst may be any catalyst that can hold NOx in the catalyst, and whether it is absorbed or adsorbed is not limited by the term of storage. Moreover, the aspect of SOx poisoning is not limited. Furthermore, the mode of NOx and SOx release is not limited.

(Operating principle)
Next, the operation principle of the control apparatus for an internal combustion engine according to the first embodiment will be described with reference to FIGS. FIG. 4 is a flowchart showing an operation flow in the control apparatus for an internal combustion engine according to the first embodiment. The operation shown in FIG. 4 is repeatedly executed at a predetermined cycle such as several microseconds. FIG. 5 is a graph showing the operating state of the engine according to the first embodiment by the rotational speed of the engine and the output torque of the engine. The vertical axis in FIG. 5 indicates the engine output torque (N · m: Newton meter), and the horizontal axis indicates the engine speed (rpm: revolution per minute). FIG. 6 shows a change in the turbo rotation speed on the time axis, a change in the variable DF opening on the time axis, and the opening of the diesel throttle valve 70 on the time axis in the control apparatus for the internal combustion engine according to the first embodiment. It is the graph (Drawing 6 (a), Drawing 6 (b), Drawing 6 (c), and Drawing 6 (d)) which showed change on a time axis of change and the opening of variable nozzle 6v, respectively.

  First, as shown in FIG. 4, the ECU 20 changes the opening degree of the variable diffuser 6n (hereinafter referred to as “variable DF” as appropriate) according to the traveling state of the vehicle. ) To determine whether switching from the opening to the opening (or opening) is required (step S101). As a result of the determination in step S101, when it is determined that switching of the opening of the variable diffuser 6n is requested under the control of the ECU 20 (step S101: Yes), the engine operating state is further controlled under the control of the ECU 20. It is determined whether it is within the mode range (step S102).

  Here, the mode range according to the present embodiment refers to the engine operating state that is quantitatively and qualitatively defined by the engine rotational speed and the engine output torque so that EGR (Exhaust Gas Recirculation) can be performed. Means. Typically, as shown in FIG. 5, the mode range means an operating state of the engine in which the engine rotation speed is at a low level and the engine output torque is at a low level.

  As a result of the determination in step S102, when it is determined that the engine operating state is within the mode range under the control of the ECU 20 (step S102: Yes), the opening degree of the variable diffuser 6n is controlled under the control of the ECU 20. As a change to the above, in addition to the switching from the opening degree on the valve closing side to the opening degree on the valve opening side, valve closing control of the diesel throttle valve 70 is executed (step S103).

  Here, the valve closing control of the diesel throttle valve 70 is a change of the opening of the variable diffuser 6n by a predetermined amount from the reference opening serving as a reference according to the traveling state of the vehicle. It means the opening degree control of the diesel throttle valve 70 that is simultaneously closed. The predetermined amount of opening of the diesel throttle valve 70 can be individually and specifically defined so as to reduce the degree of lean air-fuel ratio.

  As a result, the operating state of the engine is within the range of the mode region, and the degree to which the air-fuel ratio becomes lean as the variable diffuser 6n is switched from the opening degree on the valve closing side to the opening degree on the valve opening side is effectively reduced. Can be reduced. As a result, the degree to which harmful gases such as NOx are exhausted due to lean air-fuel ratio can be effectively reduced.

  In particular, the diesel throttle valve 70 is provided in the intake system in the same manner as the variable diffuser 6n and is located upstream of the EGR valve 14. Therefore, the intake air amount adjustment associated with the opening degree control of the EGR valve 14 is performed with high accuracy and speed. can do.

  On the other hand, as a result of the determination in step S102, when it is not determined that the engine operating state is within the mode range under the control of the ECU 20 (step S102: No), the engine operating state is further controlled under the control of the ECU 20. Is determined to be within the in-cylinder pressure limit range (step S104).

  Here, the in-cylinder pressure limit region according to the present embodiment is the engine rotation speed and the output torque of the engine when the combustion pressure associated with the combustion of fuel in the engine cylinder physically damages the engine. It means the operating state of the engine set quantitatively and qualitatively so as not to exceed the upper limit value. Typically, as shown in FIG. 5, the in-cylinder pressure limit region means an operating state of the engine in which the engine rotational speed is at a high level and the engine output torque is at a high level.

  As a result of the determination in step S104, when it is determined that the engine operating state is within the in-cylinder pressure limit range under the control of the ECU 20 (step S104: Yes), the variable diffuser 6n is controlled under the control of the ECU 20. Switching from the opening on the valve closing side to the opening on the valve opening side, valve closing control of the diesel throttle valve 70, and valve opening control of the variable nozzle 6v are executed (step S107). Here, the valve opening control of the variable nozzle 6v means that the opening of the variable nozzle 6v is opened simultaneously with the change of the opening of the variable diffuser 6n by a predetermined amount from the reference opening serving as a reference according to the running state of the vehicle. This means opening control of the variable nozzle 6v to be valved. The predetermined amount of opening of the variable nozzle 6v can be individually and specifically defined so as to reduce the rotational speed of the turbine 6b.

  As a result, the engine operating state is in the range of the in-cylinder pressure limit range, and the degree to which the air-fuel ratio becomes leaner as the variable diffuser 6n is switched from the opening on the valve closing side to the opening on the valve opening side is further increased. It can be effectively reduced. As a result, the degree to which harmful gas is exhausted by leaning the air-fuel ratio can be effectively reduced.

  In particular, the ECU 20 changes the opening of the variable nozzle 6v, the change of the opening of the variable diffuser 6n, and the diesel throttle as shown at time T1 in FIGS. 6 (b), 6 (c) and 6 (d). It can be changed simultaneously with the valve closing control of the valve 70. Thereby, since the rotational speed of the turbine 6b can be changed simultaneously with the change of the opening degree of the variable diffuser 6n, a supercharging pressure can be changed rapidly. Thereby, the adjustment of the intake air amount accompanying the change of the opening degree of the variable diffuser 6n can be executed quickly.

  Typically, in the present embodiment, as shown at time T1 in FIGS. 6A and 6B, the rotational speed of the turbine 6b can be changed simultaneously with the change in the opening degree of the variable diffuser 6n. it can. As a result, as shown in FIG. 6A, the present embodiment is a comparative example (so-called supercharger) that controls the opening of the variable nozzle 6v so that the measured supercharging pressure approaches the desired supercharging pressure. Compared with the comparative example in which the feedback control of the supply pressure is performed), the rotational speed of the turbine 6b trying to continue to rotate due to inertia can be rapidly reduced.

  Thus, when the operating state of the engine is within the range of the in-cylinder pressure limit, that is, in the so-called full load range, the increase in the pressure in the cylinder may exceed the limit value due to the increase of the supercharging pressure. Therefore, it is excessive to execute the valve closing control of the diesel throttle valve 70 and the valve opening control of the variable nozzle 6v in accordance with the switching from the valve closing side opening to the valve opening side opening in the variable diffuser 6n. It is very useful in practice because it can effectively reduce the supply pressure and improve the durability of the engine.

  On the other hand, as a result of the determination in step S104, if it is not determined that the engine operating state is within the in-cylinder pressure limit range under the control of the ECU 20 (step S104: No), the accelerator indicated by the vehicle driver It is determined whether or not the opening degree Acc is below a predetermined value (step S105). This predetermined value may mean the accelerator opening required when the vehicle is accelerated at a constant acceleration.

  As a result of the determination in step S105, under the control of the ECU 20, if it is not determined that the accelerator opening Acc instructed by the vehicle driver is below a predetermined value, in other words, the accelerator opening Acc instructed by the vehicle driver is When it is determined that the value exceeds or equals the predetermined value (step S105: No), under the control of the ECU 20, in the normal range, the opening of the variable diffuser 6n is changed from the opening on the valve closing side to the opening on the valve opening side. Switching to the degree is executed (step S106). Here, the normal range according to the present embodiment means an operating state of the engine that is quantitatively and qualitatively set so as to exclude the mode range and exclude the in-cylinder pressure limit range. Typically, as shown in FIG. 5, the normal range means an operating state of the engine in which the engine rotation speed is at a medium level and the engine output torque is at a medium level.

  As a result, in the normal range, the increased boost pressure and the increased intake air amount are used for accelerating the vehicle as the variable diffuser 6n is switched from the opening degree on the valve closing side to the opening degree on the valve opening side. can do. Thereby, coexistence with the reduction of the degree to which harmful gas is exhausted and the acceleration of a vehicle is realizable.

  On the other hand, as a result of the determination in step S105, when it is determined that the accelerator opening degree Acc instructed by the driver of the vehicle is below a predetermined value under the control of the ECU 20 (step S105: Yes), as described above, the ECU 20 As a change in the opening of the variable diffuser 6n, in addition to switching from the opening on the valve closing side to the opening on the valve opening side, the valve closing control of the diesel throttle valve 70 is executed. (Step S103). In particular, the valve closing control of the diesel throttle valve 70 is performed by changing the opening degree of the diesel throttle valve 70 from the reference opening degree that is a reference according to the traveling state of the vehicle (typically, the vehicle speed) to the accelerator opening degree. It is preferable to close the valve by a predetermined amount that is a corresponding amount and that reduces the degree of leanness of the air-fuel ratio.

  As a result, when the operating state of the engine is within the normal range, the degree of exhaust of harmful gas is reduced, and the response of the vehicle to the accelerator opening indicated by the driver is improved (so-called driving operability). (That is, improvement in drivability) can be realized.

(Examination of actions and effects according to the first embodiment)
Next, with reference to FIG. 7, the operation and effect according to the first embodiment will be examined. FIG. 7 is a graph showing the quantitative or qualitative characteristics of the pressure ratio and the air flow rate in the compressor 6a according to the first embodiment and the comparative example (FIGS. 7A and 7B). It is. The vertical axis | shaft in Fig.7 (a) and FIG.7 (b) shows the pressure ratio which is ratio of the pressure of the inlet of the compressor 6a, and the pressure of the outlet of the compressor 6a. Moreover, the horizontal axis in Fig.7 (a) and FIG.7 (b) shows an air flow rate. This air flow rate is obtained when the flow rate of air flowing into the compressor 6a is set to a constant value (for example, 25 degrees Celsius) at the inlet of the compressor 6a and the pressure is set to a constant value (for example, 101.3 KPa (kilo pascal)). It may mean a corrected air flow rate that is a value corrected or converted to the air flow rate at.

  Note that a point Pa in FIGS. 7A and 7B indicates an actual operating point of the compressor 6a, and a point P1 is when the variable DF is open and the rotational speed of the turbine is the speed V0. The operating point of the compressor 6a is shown, and the point P2 shows the operating point of the compressor 6a when the variable DF is on the open side and the rotational speed of the turbine is the speed V1. 7 (a) and 7 (b), the alternate long and short dash line curve indicates the operating line of the compressor 6a when the turbine rotational speed is the speed V0, and the solid line curve indicates the turbine rotational speed. The operating line of the compressor 6a when the speed is V1 is shown.

  7A and 7B, the dotted line L1 indicates the surge line of the compressor 6a when the variable DF vane is on the closed side, and the dotted line L2 indicates the compressor when the variable DF is on the open side. 6a shows a surge line. That is, in the compressor 6a, the surge line changes between the dotted line L1 and the dotted line L2 by changing the position of the vane of the variable DF. Point Pa in FIG. 7A and FIG. 7B indicates an operating point at which the compressor 6a is actually operating. In addition, a surge region where a surge, which is a phenomenon in which intake air flows backward, is a region on the left side of each surge line in FIGS. 7 (a) and 7 (b). That is, when the operating point Pa of the compressor 6a exceeds each surge line for a constant air flow rate, a surge is generated. In general, the flow rate of the air flowing into the compressor 6a is large, but there is a high possibility that a surge will occur, and the variable DF is on the open side, while the possibility that a surge will occur in the compressor 6a is low. The state of the variable DF on the closed side in which the flow rate of the air is small is appropriately switched under the control of the ECU.

  In general, the air flow rate indicated by the operating point Pa at which the compressor 6a is actually operating uniquely corresponds to the rotational speed of the turbine 6b. In particular, when the rotational speed of the turbine 6b is constant, the air flow rate of the compressor 6a in the open state of the variable DF is larger than the air flow rate of the compressor 6a in the close side of the variable DF.

  If only the switching from the opening on the valve closing side to the opening on the valve opening side is performed as a change in the opening of the variable diffuser 6n, as shown in the comparative example of FIG. Focusing on the moment of switching from the opening on the valve closing side to the opening on the valve opening side in DF, at this moment, the rotational speed of the turbine 6b remains at the same speed V1 as the speed before switching. Therefore, as shown in the movement from the point P1 to the point P2 in FIG. 7B, the actual operation of the compressor 6a is performed simultaneously with the switching from the valve closing side opening to the valve opening side opening in the variable DF. The point Pa moves to the side where the air flow rate increases, in other words, the air flow rate of the compressor 6a increases according to the opening degree on the valve opening side. Then, after a predetermined time has elapsed, the rotational speed of the turbine 6b becomes an air flow rate that uniquely corresponds to the speed V0 (where V1> V0). Thus, in the comparative example, there is a possibility that the air flow rate of the compressor 6a may increase unintentionally, and there arises a technical problem that the degree of exhausting harmful gas increases due to the lean air-fuel ratio. . Alternatively, the engine output torque unintentionally fluctuates due to the lean air-fuel ratio, resulting in a technical problem that the driver's driving operability (so-called drivability) decreases.

  On the other hand, according to the first embodiment, as a change in the opening degree of the variable diffuser 6n, in addition to switching from the opening degree on the valve closing side to the opening degree on the valve opening side, the diesel throttle The valve closing control of the valve 70 is executed. In other words, the opening degree of the diesel throttle valve 70 changes to the valve closing side simultaneously with switching from the valve opening side opening to the valve opening side opening in the variable DF. Alternatively, according to the first embodiment, as a change in the opening degree of the variable diffuser 6n, in addition to the switching from the opening degree on the valve closing side to the opening degree on the valve opening side, the opening of the variable nozzle 6v is performed. Valve control is executed. In other words, simultaneously with switching from the opening degree on the valve closing side to the opening degree on the valve opening side in the variable DF, the opening degree of the variable nozzle 6v is changed to the valve opening side to reduce the rotational speed of the turbine 6b.

  As a result, in spite of the switching from the opening degree on the valve closing side to the opening degree on the valve opening side in the variable DF, as shown at a point P1 in FIG. The operating point Pa does not move to the side where the air flow rate increases, in other words, the degree of increase of the air flow rate of the compressor 6a approaches zero as much as the opening degree of the diesel throttle valve 70 changes to the valve closing side.

  As a result, in the variable DF, when switching from the opening degree on the valve closing side to the opening degree on the valve opening side, it is possible to effectively reduce the degree to which the air-fuel ratio becomes lean. As a result, the degree to which harmful gas is exhausted by leaning the air-fuel ratio can be effectively reduced. Alternatively, it is possible to effectively suppress fluctuations in the output torque of the engine and to improve the driving operability (so-called drivability) of the driver.

(Second Embodiment)
(Basic configuration)
Next, an internal combustion engine control apparatus according to a second embodiment will be described with reference to FIGS. First, a basic configuration of a vehicle equipped with the control device for an internal combustion engine according to the second embodiment will be described with reference to FIG. FIG. 8 is a schematic diagram schematically showing the basic configuration of a vehicle equipped with the control device for an internal combustion engine according to the second embodiment. Of the constituent elements of the second embodiment, constituent elements that are substantially the same as those of the first embodiment described above are given the same reference numerals, and descriptions thereof are omitted as appropriate.

  As shown in FIG. 8, the engine 1 according to the second embodiment includes an electronic throttle valve 2, an AFM (Air Flow Meter) 2a, cylinders # 1 to # 4, an intake passage 3, an intake manifold 3M, an exhaust manifold 4, Intercooler 5, air filter 5f for intake air filtration, turbocharger 6, compressor 6a, turbine 6b, angle sensor 6s for measuring the angle of the rectifying blades of variable diffuser 6n, and the supercharging pressure of the intake system of engine 1 are measured. A supercharging pressure sensor 7s, a DPNR catalyst 8, an exhaust purification unit 9, a fuel addition valve 10, an EGR passage 11, an EGR catalyst 12, an EGR cooler 13, an EGR valve 14, an exhaust throttle valve 15, a muffler 16, an ECU 20, an injector 30, Common rail 31, fuel pump 32, crank angle sensor 33 for measuring the engine speed, Pressure sensor 40, the intake air amount adjustment of the throttle valve for measuring the force (so-called diesel throttle valve) 70 and is configured to include a variable valve mechanism 80.

  The variable valve mechanism 80 is a mechanism that can change the closing timing of the intake valve. Typically, the variable valve mechanism 80 can execute retard control for retarding the closing timing of the intake valve or advance control for advancing the closing timing of the intake valve.

(Operating principle)
Next, control processing in the control apparatus for an internal combustion engine according to the second embodiment will be described with reference to FIG. FIG. 9 is a flowchart showing an operation flow in the control apparatus for an internal combustion engine according to the second embodiment. The operation shown in FIG. 9 is repeatedly executed at a predetermined cycle such as several microseconds.

  First, as shown in FIG. 9, the ECU 20 is required to switch from the opening on the valve closing side to the opening on the valve opening side as a change in the opening of the variable diffuser 6n in accordance with the running state of the vehicle. It is determined whether or not (step S201). As a result of the determination in step S201, when it is determined that switching of the opening of the variable diffuser 6n is requested under the control of the ECU 20 (step S201: Yes), the engine operating state is further controlled under the control of the ECU 20. It is determined whether it is within the range of the mode range or the range of the in-cylinder pressure limit range (step S202). As a result of the determination in step S202, when it is determined that the operating state of the engine is within the mode range or the in-cylinder pressure limit range (step S202: Yes), the mode range is controlled under the control of the ECU 20. Alternatively, in the in-cylinder pressure limit region, as a change in the opening degree of the variable diffuser 6n, in addition to the switching from the opening degree on the valve closing side to the opening degree on the valve opening side, the closing timing of the variable valve mechanism is performed. Is retarded (step S203). Here, “retarding control for retarding the valve closing timing of the variable valve mechanism” according to the present embodiment means that the valve closing timing of the variable valve mechanism is a reference timing that serves as a reference according to the running state of the vehicle. Means control of the variable valve mechanism that is delayed by a predetermined time. The predetermined time can be individually and specifically defined so as to reduce the amount of intake air taken into the cylinder. The predetermined time may be defined by the engine rotation speed and the engine crank angle.

  As a result, the degree to which the air-fuel ratio becomes lean can be effectively reduced in the mode region or the in-cylinder pressure limit region. As a result, the degree to which harmful gas is exhausted by leaning the air-fuel ratio can be effectively reduced.

  In particular, in the mode region, the temperature inside the cylinder at the end of the compression stroke, the so-called compression end temperature, can be lowered by retarding the valve closing timing of the variable valve mechanism, so harmful gases are exhausted. In practice, it is very beneficial. Or, in particular, in the in-cylinder pressure limit region, the pressure in the cylinder can be effectively reduced by retarding the valve closing timing of the variable valve mechanism, thereby improving the physical durability of the engine. This is very useful in practice.

  As a result of the determination in step S202 described above, if it is determined that the engine operating state is not within the mode range and is not within the in-cylinder pressure limit range, in other words, the engine operating state is within the mode range. When it is determined that the vehicle is outside the range and outside the range of the in-cylinder pressure limit range (step S202: No), whether or not the accelerator opening degree Acc instructed by the driver of the vehicle is below a predetermined value. Is determined (step S204). This predetermined value may mean the accelerator opening required when the vehicle is accelerated at a constant acceleration.

  As a result of the determination in step S204, if it is not determined that the accelerator opening Acc instructed by the vehicle driver is below a predetermined value under the control of the ECU 20, in other words, the accelerator opening Acc instructed by the vehicle driver is When it is determined that the value exceeds or equals the predetermined value (step S204: No), under the control of the ECU 20, in the normal range, the opening of the variable diffuser 6n is changed from the opening on the valve closing side to the opening on the valve opening side. Switching to the degree is executed (step S206).

  As a result, in the normal range, the boost pressure and the increased intake air amount that are increased by switching from the opening degree on the valve closing side to the opening degree on the valve opening side in the variable diffuser 6n are used for acceleration of the vehicle. be able to. Thereby, coexistence with the reduction of the degree to which harmful gas is exhausted and the acceleration of a vehicle is realizable.

  On the other hand, as a result of the determination in step S204 described above, when it is determined that the accelerator opening degree Acc instructed by the driver of the vehicle is below a predetermined value under the control of the ECU 20 (step S204: Yes), under the control of the ECU 20. In addition to changing the opening degree of the variable diffuser 6n from the opening degree on the valve closing side to the opening degree on the valve opening side, the valve closing timing of the variable valve mechanism according to the accelerator opening degree. Is executed (step S205). In particular, in the retard control of the valve closing timing of the variable valve mechanism, it is preferable to delay by the retard amount that is an amount corresponding to the accelerator opening and that reduces the degree of leaning of the air-fuel ratio.

  As a result, when the operating state of the engine is within the normal range, the degree of exhaust of harmful gas is reduced, and the response of the vehicle to the accelerator opening indicated by the driver is improved (so-called driving operability). And improvement in drivability) can be realized.

(Third embodiment)
(Basic configuration)
Next, an internal combustion engine control apparatus according to a third embodiment will be described with reference to FIGS. First, a basic configuration of a vehicle equipped with the control device for an internal combustion engine according to the third embodiment will be described with reference to FIG. FIG. 10 is a schematic diagram schematically showing the basic configuration of a vehicle equipped with the control device for an internal combustion engine according to the third embodiment. Of the constituent elements of the third embodiment, constituent elements that are substantially the same as those of the first embodiment described above are given the same reference numerals, and descriptions thereof are omitted as appropriate.

  As shown in FIG. 10, the engine 1 according to the third embodiment includes an electronic throttle valve 2, an AFM (Air Flow Meter) 2a, cylinders # 1 to # 4, an intake passage 3, an intake manifold 3M, an exhaust manifold 4, Intercooler 5, air filter 5f for intake air filtration, turbocharger 6, compressor 6a, turbine 6b, motor generator 6m, angle sensor 6s for measuring the angle of the rectifying blades of variable diffuser 6n, intake system of engine 1 A supercharging pressure sensor 7s for measuring a supercharging pressure, a DPNR catalyst 8, an exhaust purification unit 9, a fuel addition valve 10, an EGR passage 11, an EGR catalyst 12, an EGR cooler 13, an EGR valve 14, an exhaust throttle valve 15, a muffler 16, ECU 20, injector 30, common rail 31, fuel pump 32, crank angle sensor for measuring engine speed 3, the pressure sensor 40 for measuring the pressure in the cylinder, and the intake air amount adjustment of the throttle valve (so-called diesel throttle valve) is configured to include a 70.

  The motor generator 6m is a motor generator capable of changing the rotational speed of the turbine 6b. Typically, the motor generator 6m can decelerate the rotational speed of the turbine 6b by regeneration of electric power. Alternatively, the motor generator 6m can accelerate the rotational speed of the turbine 6b by power running, and can perform so-called motor-assisted turbocharging.

  The rotational state such as the rotational speed and rotational torque in the motor generator 6m is controlled by the ECU 20 described above.

(Operating principle)
Next, control processing in the control apparatus for an internal combustion engine according to the third embodiment will be described with reference to FIGS. 11 and 12. FIG. 11 is a flowchart showing an operation flow in the control apparatus for an internal combustion engine according to the third embodiment. The operation shown in FIG. 11 is repeatedly executed at a predetermined cycle such as several microseconds. In the third embodiment, processes that are substantially the same as those in the second embodiment described above are given the same step numbers, and descriptions thereof are omitted as appropriate. FIG. 12 shows changes in the time axis of the turbo rotation speed, changes in the opening degree of the variable DF on the time axis, and on the time axis in which regeneration is performed and not performed in the control apparatus for an internal combustion engine according to the third embodiment. 12 is a graph (FIG. 12A, FIG. 12B, and FIG. 12C) showing the change of each. Note that turning off the regeneration flag in FIG. 12C indicates that regeneration is not performed, and turning on the regeneration flag indicates that regeneration is performed.

  As a result of the determination in step S202 described above, when it is determined that the engine operating state is within the mode range or in-cylinder pressure limit range (step S202: Yes), the mode is controlled under the control of the ECU 20. In the region or the in-cylinder pressure limit region, in addition to the switching from the opening on the valve closing side to the opening on the valve opening side as a change in the opening of the variable diffuser 6n, the electric power generated by the motor generator 6m Regeneration is performed, and the rotational speed of the turbine 6b is decelerated (step S301). The degree of deceleration of the rotational speed of the turbine 6b due to regeneration of the motor generator can be individually and specifically defined so as to reduce the supercharging pressure and the intake air amount.

  Typically, in this embodiment, as shown in FIG. 12B and FIG. 12C, the opening on the valve opening side is changed from the opening on the valve closing side as a change in the opening of the variable diffuser 6n. Simultaneously with the execution of switching to, regeneration of electric power by the motor generator is executed at time T1. Thereby, as FIG. 12A shows, the rotational speed of the turbine 6b can be decelerated simultaneously with the change of the opening degree of the variable diffuser 6n. Thus, as shown in FIG. 12A, according to the present embodiment, the rotation continues due to inertia compared to the comparative example in which the rotational speed of the turbine 6b is not reduced by the regeneration of electric power in the motor generator. The rotational speed of the turbine 6b to be attempted can be rapidly reduced.

  As a result, the degree to which the air-fuel ratio becomes lean can be effectively reduced in the mode region or the in-cylinder pressure limit region. As a result, the degree to which harmful gas is exhausted by leaning the air-fuel ratio can be effectively reduced.

  In particular, in the in-cylinder pressure limit region, the supercharging pressure can be effectively reduced by reducing the rotational speed of the turbine 6b using regeneration of electric power in the motor generator, and the pressure in the cylinder is effectively reduced. Can improve the durability of the engine, which is very useful in practice.

  On the other hand, as a result of the determination in step S204 described above, when it is determined that the accelerator opening degree Acc instructed by the driver of the vehicle is below a predetermined value under the control of the ECU 20 (step S204: Yes), under the control of the ECU 20. In addition to changing the opening degree of the variable diffuser 6n from the opening degree on the valve closing side to the opening degree on the valve opening side, the regeneration of electric power by the motor generator according to the accelerator opening degree is performed. This is executed to reduce the rotational speed of the turbine 6b (step S302). In particular, the amount of regeneration in regeneration of electric power by the motor generator is preferably an amount corresponding to the accelerator opening and an amount that reduces the degree to which the air-fuel ratio becomes lean.

  As a result, when the operating state of the engine is within the normal range, the degree of exhaust of harmful gas is reduced, and the response of the vehicle to the accelerator opening indicated by the driver is improved (so-called driving operability). And improvement in drivability) can be realized.

(Fourth embodiment)
(Basic configuration)
Next, a control device for an internal combustion engine according to a fourth embodiment will be described with reference to FIGS. First, with reference to FIG. 13, a basic configuration of a vehicle equipped with the control device for an internal combustion engine according to the fourth embodiment will be described. FIG. 13 is a schematic diagram schematically showing the basic configuration of a vehicle equipped with the control device for an internal combustion engine according to the fourth embodiment. Of the constituent elements of the fourth embodiment, constituent elements that are substantially the same as those of the first embodiment described above are given the same reference numerals, and descriptions thereof are omitted as appropriate.

  As shown in FIG. 13, the engine 1 according to the fourth embodiment includes an electronic throttle valve 2, an AFM (Air Flow Meter) 2a, cylinders # 1 to # 4, an intake passage 3, an intake manifold 3M, an exhaust manifold 4, Intercooler 5, air filter 5f for intake air filtration, turbocharger 6, compressor 6a, turbine 6b, angle sensor 6s for measuring the angle of the rectifying blades of variable diffuser 6n, and the supercharging pressure of the intake system of engine 1 are measured. A supercharging pressure sensor 7s, a DPNR catalyst 8, an exhaust purification unit 9, a fuel addition valve 10, an EGR passage 11, an EGR catalyst 12, an EGR cooler 13, an EGR valve 14, an exhaust throttle valve 15, a muffler 16, an ECU 20, an injector 30, Common rail 31, fuel pump 32, crank angle sensor 33 for measuring the engine speed, in the cylinder Pressure sensor 40 for measuring the pressure, continuously variable transmission 50, and the intake air amount adjustment of the throttle valve (so-called diesel throttle valve) is configured to include a 70.

  The continuously variable transmission 50 is a continuously variable transmission such as a CVT (Continuous Variable Transmission), for example, and can continuously change the output state of the engine 1 such as the rotational speed and rotational torque of the engine 1.

(Operating principle)
Next, control processing in the control apparatus for an internal combustion engine according to the fourth embodiment will be described with reference to FIG. FIG. 14 is a flowchart showing an operation flow in the control apparatus for an internal combustion engine according to the fourth embodiment. The operation shown in FIG. 14 is repeatedly executed at a predetermined cycle such as several microseconds. In the fourth embodiment, processes that are substantially the same as those in the first embodiment described above are given the same step numbers, and descriptions thereof are omitted as appropriate.

  As a result of the determination in step S102 described above, when it is determined that the engine operating state is within the mode range under the control of the ECU 20 (step S102: Yes), the variable diffuser 6n is opened under the control of the ECU 20. As a change in the degree, switching from the opening on the valve closing side to the opening on the valve opening side, delay angle control for delaying the fuel injection timing, and shift by the continuously variable transmission are executed (step S401). ). Here, the “retarding control for retarding the fuel injection timing” according to the present embodiment refers to a fuel injection timing that delays the fuel injection timing by a predetermined time from a reference timing that is a reference according to the running state of the vehicle. Means injection control. This predetermined time can be individually and specifically defined so as to reduce the combustion pressure generated by the combustion of the fuel. The predetermined time may be defined by the engine rotation speed and the engine crank angle. In addition, the shift by the continuously variable transmission according to the present embodiment is executed individually and specifically so as to reduce fluctuations in the output torque of the engine by retard control that retards the fuel injection timing.

  By reducing the fuel combustion pressure by retarding the fuel injection timing, the opening of the variable diffuser 6n from the opening on the valve closing side to the opening on the valve opening side is reduced. The degree of leaning of the air-fuel ratio can be effectively reduced with the changeover to. As a result, the degree to which harmful gas is exhausted by leaning the air-fuel ratio can be effectively reduced.

  As a result of the determination in step S104 described above, when it is determined that the engine operating state is within the in-cylinder pressure limit region under the control of the ECU 20 (step S104: Yes), the variable diffuser 6n is controlled under the control of the ECU 20. Is switched from the opening on the valve closing side to the opening on the valve opening side, and the retard control is performed to retard the fuel injection timing (step S403).

  As a result, in the operating state of the engine in the in-cylinder pressure limit region, the degree to which the air-fuel ratio becomes leaner more effectively as the variable diffuser 6n is switched from the opening on the valve closing side to the opening on the valve opening side is more effective. Can be reduced. As a result, the degree to which harmful gas is exhausted by leaning the air-fuel ratio can be effectively reduced. In particular, in the in-cylinder pressure limit region, the supercharging pressure can be effectively reduced by the retard control that retards the fuel injection timing, and the pressure in the cylinder can be effectively reduced. Since it can improve the durability, it is very useful in practice.

  On the other hand, as a result of the determination in step S105 described above, when it is determined that the accelerator opening Acc instructed by the driver of the vehicle is below a predetermined value under the control of the ECU 20 (step S105: Yes), under the control of the ECU 20. Then, switching from the opening on the valve closing side to the opening on the valve opening side as a change in the opening of the variable diffuser 6n, and a shift by the continuously variable transmission are executed (step S402).

  In particular, various speed-related parameters such as shift timing and shift speed change in the continuously variable transmission are set according to the accelerator opening and set so that the degree of lean air-fuel ratio can be reduced. It is preferable to do.

  As a result, when the engine is operating in the normal range, the degree to which harmful gases are exhausted is reduced, and the responsiveness of the vehicle to the accelerator opening indicated by the driver is improved (so-called driving operability, that is, drivability is improved). ) Can be realized.

(Fifth embodiment)
(Operating principle)
Next, control processing in the control apparatus for an internal combustion engine according to the fifth embodiment will be described with reference to FIGS. 15 to 17. FIG. 15 is a flowchart showing an operation flow in the control apparatus for an internal combustion engine according to the fifth embodiment. The operation shown in FIG. 15 is repeatedly executed at a predetermined cycle such as several microseconds. In addition, since the components of the fifth embodiment are substantially the same as those of the first embodiment described above, description thereof will be omitted as appropriate. FIG. 16 is a graph showing the operating state of the engine according to the fifth embodiment by the engine speed and the engine output torque. The vertical axis in FIG. 16 represents the engine output torque (N · m: Newton meter), and the horizontal axis represents the engine rotation speed (rpm: revolution per minute).

  First, as shown in FIG. 15, the ECU 20 is required to switch from the opening degree on the valve opening side to the opening degree on the valve closing side as a change in the opening degree of the variable diffuser 6n according to the running state of the vehicle. It is determined whether or not (step S501). As a result of the determination in step S501, when it is determined that switching of the opening degree of the variable diffuser 6n is requested under the control of the ECU 20 (step S501: Yes), the engine operating state is further controlled under the control of the ECU 20. It is determined whether it is within the mode range (step S502). Here, the mode range according to the fifth embodiment means an operating state of the engine that implements EGR defined by the rotational speed of the engine and the output torque of the engine.

  As a result of the determination in step S502 described above, when it is determined that the engine operating state is within the mode range under the control of the ECU 20 (step S502: Yes), the diesel throttle valve 70 is controlled under the control of the ECU 20. It is determined whether or not the opening is in a fully open state (step S503). As a result of the determination in step S503, when it is determined that the opening of the diesel throttle valve 70 is in a fully open state under the control of the ECU 20 (step S503: Yes), the opening of the variable diffuser 6n is controlled under the control of the ECU 20. As a change to the above, in addition to the switching from the opening on the valve opening side to the opening on the valve closing side, the valve closing control of the EGR valve 14 is executed (step S504). Typically, under the condition that the opening degree of the diesel throttle valve 70 is fully open, the opening degree of the EGR valve 14 is changed simultaneously with the switching from the opening degree on the variable DF to the opening degree on the valve closing side. Change to the valve closing side. In particular, the valve closing control of the EGR valve 14 is performed by changing the opening of the EGR valve 14 according to the accelerator opening from a reference opening that is a reference according to the traveling state of the vehicle (typically, the speed of the vehicle). It is preferable to close the valve by a predetermined amount that is an amount and an amount that reduces the degree to which the air-fuel ratio becomes rich.

  As a result, when the variable DF is switched from the opening degree on the valve opening side to the opening degree on the valve closing side, the degree to which the air-fuel ratio becomes rich can be effectively reduced. Thereby, in the second mode region, it is possible to effectively reduce the degree to which harmful gas is exhausted by enrichment of the air-fuel ratio. Alternatively, in the second mode region, it is possible to effectively suppress fluctuations in the output torque of the engine and to improve the driver's driving operability (so-called drivability). Here, the second mode region according to the fifth embodiment means an operating state in which EGR is performed in the acceleration state of the vehicle and the opening degree of the diesel throttle valve 70 is fully open. As shown in FIG. 16, it means an engine operating state in which the engine rotational speed is at a medium level and the engine output torque is at a medium level.

  As a result of the determination in step S503 described above, when it is not determined that the opening degree of the diesel throttle valve 70 is in the fully open state under the control of the ECU 20, in other words, it is determined that the opening degree of the diesel throttle valve 70 is not in the fully open state. In the case (step S503: No), under the control of the ECU 20, the opening of the variable diffuser 6n is changed from the opening on the valve opening side to the opening on the valve closing side in addition to the diesel opening. The valve opening control of the throttle valve 70 is executed (step S505). In particular, in the opening control of the diesel throttle valve 70, the opening degree of the diesel throttle valve 70 is set from the reference opening degree which becomes a reference according to the traveling state of the vehicle (typically, the speed of the vehicle). It is preferable to open the valve by a predetermined amount that increases the air-fuel ratio and reduces the degree of air-fuel ratio enrichment.

  As a result, when the variable DF is switched from the opening degree on the valve opening side to the opening degree on the valve closing side, when the engine operating state is within the range of the first mode region, the degree to which harmful gas is exhausted. It is possible to realize both the reduction and the improvement of the vehicle responsiveness to the accelerator opening instructed by the driver (so-called driving operability, that is, improvement of drivability). Here, the first mode region according to the fifth embodiment means an operating state in which the EGR is performed in the acceleration state of the vehicle and the opening degree of the diesel throttle valve 70 is not a fully open state. Typically, as shown in FIG. 16, it means an operating state of the engine in which the engine rotational speed is at a low level and the engine output torque is at a low level.

  As a result of the determination in step S502 described above, when it is not determined that the engine operating state is within the mode range under the control of the ECU 20, in other words, it is determined that the engine operating state is not within the mode range. (Step S502: No), under the control of the ECU 20, in addition to the change from the opening on the valve opening side to the opening on the valve closing side as a change in the opening of the variable diffuser 6n, The valve closing control of the variable nozzle 6v is executed (step S506). In other words, simultaneously with switching from the opening degree on the variable DF to the opening degree on the valve closing side, the opening degree of the variable nozzle 6v is changed to the valve closing side to increase the rotational speed of the turbine 6b. Here, the valve closing control of the variable nozzle 6v is the opening control of the variable nozzle 6v for closing the opening of the variable nozzle 6v by a predetermined amount from the reference opening serving as a reference according to the running state of the vehicle. means. The predetermined amount of the opening degree of the variable nozzle 6v can be individually and specifically defined so as to increase the rotational speed of the turbine 6b and thus increase the supercharging pressure.

  That is, the ECU 20 changes the opening of the variable nozzle 6v simultaneously with the change of the opening of the variable diffuser 6n. Thereby, since the rotational speed of the turbine 6b can be changed simultaneously with the change of the opening degree of the variable diffuser 6n, a supercharging pressure can be changed rapidly. As a result, the intake air amount can be quickly adjusted. Typically, in the fifth embodiment, the rotational speed of the turbine 6b can be increased simultaneously with the change of the opening degree of the variable diffuser 6n. Thereby, 5th Embodiment is a comparative example which controls the opening degree of the variable nozzle 6v so that the measured supercharging pressure may be brought close to a desired supercharging pressure (so-called comparative example in which feedback control of supercharging pressure is performed). As compared with, the rotational speed of the turbine 6b that tries to continue to rotate due to inertia can be rapidly increased.

  As a result, when switching from the opening on the valve opening side to the opening on the valve closing side in the variable DF, the boost pressure is increased, the intake air amount is increased, and the degree to which the air-fuel ratio becomes rich is effectively reduced. be able to. As a result, it is possible to effectively reduce the degree to which harmful gas is exhausted by enrichment of the air-fuel ratio in the operating state outside the mode range. Alternatively, this makes it possible to effectively suppress fluctuations in the engine output torque and improve the driver's driving operability (so-called drivability) in the driving state outside the mode range. The driving state outside the mode range means a driving state in which EGR is not performed in the acceleration state of the vehicle. Typically, as shown in FIG. 16, the engine rotational speed is at a high level, and It means the engine operating state where the engine output torque is at a high level.

  In particular, when a request to switch from the opening on the valve opening side to the opening on the valve closing side is made outside the mode range in the variable DF, switching from the opening on the valve opening side to the opening on the valve closing side in the variable DF is performed. At the same time, changing the opening of the variable nozzle 6v toward the valve closing side and increasing the rotational speed of the turbine 6b gives the driver a further feeling of deceleration during the deceleration operation due to the decrease in the boost pressure or the intake air amount. Can be effectively prevented, so that it is very useful in practice in terms of improving the driving operability (so-called drivability) of the driver.

(Examination of actions and effects according to the fifth embodiment)
Next, with reference to FIG. 17, the effect | action and effect which concern on 5th Embodiment are examined. FIG. 17 is a graph showing quantitative or qualitative characteristics of the pressure ratio and the air flow rate in the compressor 6a according to the fifth embodiment and the comparative example (FIGS. 17A and 17B). It is. The vertical axis | shaft in Fig.17 (a) and FIG.17 (b) shows the pressure ratio which is ratio of the pressure of the inlet of the compressor 6a, and the pressure of the outlet of the compressor 6a. Moreover, the horizontal axis in Fig.17 (a) and FIG.17 (b) shows an air flow rate. This air flow rate may mean the corrected air flow rate described above.

  Note that a point Pa in FIGS. 17A and 17B indicates an actual operating point of the compressor 6a, and a point P3 is when the variable DF is closed and the rotational speed of the turbine is the speed V1. The operating point of the compressor 6a is shown, and the point P4 shows the operating point of the compressor 6a when the variable DF is closed and the rotational speed of the turbine is the speed V0. 17 (a) and 17 (b), the alternate long and short dash line curve indicates the operating line of the compressor 6a when the turbine rotational speed is the speed V0, and the solid line curve indicates the turbine rotational speed. The operating line of the compressor 6a when the speed is V1 is shown.

  17A and 17B, the dotted line L1 indicates the surge line of the compressor 6a when the variable DF vane is on the closed side, and the dotted line L2 indicates the compressor when the variable DF is on the open side. 6a shows a surge line. That is, in the compressor 6a, the surge line changes between the dotted line L1 and the dotted line L2 by changing the position of the vane of the variable DF. A point Pa in FIGS. 17A and 17B indicates an operating point at which the compressor 6a is actually operating. In addition, a surge region where a surge, which is a phenomenon in which intake air flows backward, is a region on the left side of each surge line in FIGS. 17 (a) and 17 (b). In addition, since the general physical phenomenon regarding the rotation speed of a surge, a surge line, and a turbine is substantially the same as 1st Embodiment mentioned above, description is abbreviate | omitted.

  If the opening of the variable diffuser 6n is changed only from the opening on the valve opening side to the opening on the valve closing side, as shown in the comparative example of FIG. Focusing on the moment of switching from the opening on the valve opening side to the opening on the valve closing side in DF, at this moment, the rotational speed of the turbine 6b remains at the same speed V0 as the speed before switching. Therefore, as shown in the movement from the point P3 to the point P4 in FIG. 17B, the actual operation of the compressor 6a is performed simultaneously with switching from the opening degree on the variable DF to the opening degree on the valve closing side. The point Pa moves to the side where the air flow rate decreases, in other words, the air flow rate of the compressor 6a decreases according to the opening degree on the valve closing side. Then, after a predetermined time has elapsed, the rotational speed of the turbine 6b becomes an air flow rate that uniquely corresponds to the speed V1 (where V1> V0). Thus, in the comparative example, there is a possibility that the air flow rate of the compressor 6a may unintentionally decrease, and a technical problem that the degree of exhausting harmful gas increases due to the rich air-fuel ratio arises. . Alternatively, the engine output torque unintentionally fluctuates due to enrichment of the air-fuel ratio, resulting in a technical problem that the driver's driving operability (so-called drivability) decreases.

  On the other hand, according to the fifth embodiment, as a change in the opening degree of the variable diffuser 6n, in addition to the switching from the opening degree on the valve opening side to the opening degree on the valve closing side, the diesel throttle The valve opening control of the valve 70 is executed. In other words, the opening degree of the diesel throttle valve 70 changes to the valve opening side simultaneously with switching from the valve opening side opening in the variable DF to the valve closing side opening. Alternatively, according to the fifth embodiment, as a change in the opening degree of the variable diffuser 6n, in addition to switching from the opening degree on the valve opening side to the opening degree on the valve closing side, the variable nozzle 6v is closed. Valve control is executed. In other words, simultaneously with switching from the opening degree on the variable DF to the opening degree on the valve closing side, the opening degree of the variable nozzle 6v is changed to the valve closing side to increase the rotational speed of the turbine 6b.

  Alternatively, according to the fifth embodiment, as a change in the opening degree of the variable diffuser 6n, in addition to the switching from the opening degree on the valve opening side to the opening degree on the valve closing side, the EGR valve 14 is closed. Valve control is executed. Typically, under the condition that the opening degree of the diesel throttle valve 70 is fully open, the opening degree of the EGR valve 14 is changed simultaneously with the switching from the opening degree on the variable DF to the opening degree on the valve closing side. Change to the valve closing side. In particular, the valve closing control of the EGR valve 14 is performed by changing the opening of the EGR valve 14 according to the accelerator opening from a reference opening that is a reference according to the traveling state of the vehicle (typically, the speed of the vehicle). It is preferable to close the valve by a predetermined amount that is an amount and an amount that reduces the degree to which the air-fuel ratio becomes rich.

  As a result, in spite of the switching from the opening degree on the valve opening side to the opening degree on the valve closing side in the variable DF, as shown by a point P3 in FIG. The operating point Pa does not move to the side where the air flow rate decreases, in other words, the degree of decrease of the air flow rate of the compressor 6a approaches zero as much as the opening of the diesel throttle valve 70 changes to the valve opening side.

  As a result, in the variable DF, when the opening degree on the valve opening side is switched to the opening degree on the valve closing side, the degree of enrichment of the air-fuel ratio can be effectively reduced. Thereby, the degree to which harmful gas is exhausted by enrichment of the air-fuel ratio can be effectively reduced. Alternatively, it is possible to effectively suppress fluctuations in the output torque of the engine and to improve the driving operability (so-called drivability) of the driver.

  In particular, in an operating state in which the driver decelerates while depressing the accelerator, the tendency of the air-fuel ratio to become rich appears prominently. Therefore, the valve opening control of the diesel throttle valve 70 according to the fifth embodiment In practice, it is very beneficial to perform at least one of the valve closing control of the variable nozzle 6v and the valve closing control of the EGR valve.

(Sixth embodiment)
(Operating principle)
Next, control processing in the control apparatus for an internal combustion engine according to the sixth embodiment will be described with reference to FIG. FIG. 18 is a flowchart showing an operation flow in the control apparatus for an internal combustion engine according to the sixth embodiment. The operation shown in FIG. 18 is repeatedly executed at a predetermined cycle such as several microseconds. The components of the sixth embodiment are substantially the same as those of the second embodiment described above. In the sixth embodiment, the same step numbers are assigned to processes that are substantially the same as those in the fifth embodiment described above, and description thereof is omitted as appropriate.

  If the engine operating state is not determined to be within the range of the mode range under the control of the ECU 20 as a result of the determination in step S502 described above through step S501 described above, in other words, the engine operating state is in the mode range. When it is determined that it is not within the range (step S502: No), switching from the opening on the valve opening side to the opening on the valve closing side is executed as a change in the opening of the variable diffuser 6n under the control of the ECU 20. In addition, the advance valve control for advancing the valve closing timing of the intake valve is executed by the variable valve mechanism 80 (step S601). Here, “advance control for advancing the closing timing of the intake valve by the variable valve mechanism 80” according to the sixth embodiment means that the closing timing of the intake valve by the variable valve mechanism 80 is determined based on the travel of the vehicle. This means control of the variable valve mechanism that is advanced by a predetermined time from a reference time that is a reference according to the state. This predetermined time can be individually and specifically defined so as to increase the intake efficiency of the intake air taken into the cylinder, increase the supercharging pressure, and increase the intake air amount. The predetermined time may be defined by the engine rotation speed and the engine crank angle.

  As a result, when switching from the opening on the valve opening side to the opening on the valve closing side in the variable DF, the boost pressure is increased, the intake air amount is increased, and the degree to which the air-fuel ratio becomes rich is effectively reduced. be able to. As a result, it is possible to effectively reduce the degree to which harmful gas is exhausted by enrichment of the air-fuel ratio in the operating state outside the mode range. Alternatively, this makes it possible to effectively suppress fluctuations in the engine output torque and improve the driver's driving operability (so-called drivability) in the driving state outside the mode range.

  In particular, as described above, when the variable DF is requested to switch from the opening degree on the valve opening side to the opening degree on the valve closing side, the opening degree on the valve opening side is changed to the opening degree on the valve closing side. In addition to executing the switching, the variable valve mechanism 80 executes the advance angle control for advancing the closing timing of the intake valve. As a result, the intake efficiency can be increased and the boost pressure and intake air amount can be maintained, so that the driver can feel further deceleration during the deceleration operation due to the decrease in the boost pressure and intake air amount. It can be effectively prevented. As described above, the sixth embodiment is very useful in practice in terms of improving the driving operability (so-called drivability) of the driver.

(Seventh embodiment)
(Operating principle)
Next, control processing in the control device for an internal combustion engine according to the seventh embodiment will be described with reference to FIG. FIG. 19 is a flowchart showing an operation flow in the control apparatus for an internal combustion engine according to the seventh embodiment. The operation shown in FIG. 19 is repeatedly executed at a predetermined cycle such as several microseconds. The components of the seventh embodiment are substantially the same as those of the third embodiment described above. In the seventh embodiment, processes that are substantially the same as those in the fifth embodiment described above are given the same step numbers, and descriptions thereof are omitted as appropriate. FIG. 20 shows changes in the time axis of the turbo rotation speed, changes in the time axis of the opening degree of the variable DF, and implementation of motor-assisted turbocharging in the control apparatus for an internal combustion engine according to the seventh embodiment. It is the graph (Drawing 20 (a), Drawing 20 (b), and Drawing 20 (c)) which showed change on a non-implementation time axis, respectively. Note that turning off the motor assist flag in FIG. 20C indicates that the motor generator does not accelerate the rotation speed of the turbine 6b, and turning on the motor assist flag indicates that the rotation speed of the turbine 6b by the motor generator is not. Indicates the implementation of acceleration.

  When the opening degree of the diesel throttle valve 70 is determined to be fully open under the control of the ECU 20 as a result of the determination in step S503 through the above-described step S501 and step S502, the control of the ECU 20 is performed. Below, switching from the opening degree of the variable diffuser 6n to the opening degree of the valve closing side, valve closing control of the EGR valve 14, and acceleration of the rotational speed of the turbine 6b by the motor generator 6m, so-called motor Assist turbocharging is executed (step S701). The acceleration in the acceleration of the rotational speed of the turbine 6b by the motor generator can be individually and specifically defined so as to increase the supercharging pressure and increase the intake air amount.

  Typically, under the condition that the opening degree of the diesel throttle valve 70 is fully open, the opening degree of the EGR valve 14 is changed simultaneously with the switching from the opening degree on the variable DF to the opening degree on the valve closing side. Change to the valve closing side. In particular, the valve closing control of the EGR valve 14 is performed by changing the opening of the EGR valve 14 according to the accelerator opening from a reference opening that is a reference according to the traveling state of the vehicle (typically, the speed of the vehicle). It is preferable to close the valve by a predetermined amount that is an amount and an amount that reduces the degree to which the air-fuel ratio becomes rich.

  Typically, in the present embodiment, as shown in FIGS. 20B and 20C, the opening on the valve closing side is changed from the opening on the valve opening side as a change in the opening of the variable diffuser 6n. Simultaneously with the execution of switching to, at the time T1, acceleration of the rotational speed of the turbine 6b by the motor generator is executed. Accordingly, as shown in FIG. 20A, the rotational speed of the turbine 6b can be accelerated simultaneously with the change of the opening degree of the variable diffuser 6n. Accordingly, as shown in FIG. 20A, according to the present embodiment, the turbine that continues to rotate due to inertia compared to the comparative example in which the rotational speed of the turbine 6b is not accelerated by the motor generator. The rotational speed of 6b can be increased rapidly.

  As described above, when the rotational speed of the turbine 6b is accelerated by the motor generator and the opening degree on the variable valve side is switched from the opening degree on the valve opening side to the opening degree on the valve closing side, the excess due to the acceleration of the rotational speed of the turbine 6b. The degree to which the supply pressure is increased and the air-fuel ratio becomes rich can be more effectively reduced. Thereby, in the operation state of the second mode region, it is possible to more effectively reduce the degree to which harmful gas is exhausted due to the enrichment of the air-fuel ratio. Alternatively, this makes it possible to more effectively suppress fluctuations in the output torque of the engine in the driving state in the second mode region, and to improve the driving operability (so-called drivability) of the driver.

  As a result of the determination in step S503 described above, when it is not determined that the opening degree of the diesel throttle valve 70 is in the fully open state under the control of the ECU 20, in other words, it is determined that the opening degree of the diesel throttle valve 70 is not in the fully open state. In the case (step S503: No), under the control of the ECU 20, switching from the valve opening side opening to the valve closing side opening in the variable diffuser 6n, the valve opening control of the diesel throttle valve 70, and the motor generator The acceleration of the rotational speed of the turbine 6b (so-called motor-assisted turbocharging) is executed (step S702).

  Typically, in the valve opening control of the diesel throttle valve 70, the opening degree of the diesel throttle valve 70 is changed from a reference opening degree serving as a reference according to the running state of the vehicle (typically, the speed of the vehicle), It is preferable to open the valve by a predetermined amount that increases the supercharging pressure and reduces the degree of air-fuel ratio enrichment.

  In particular, when the rotational speed of the turbine 6b is accelerated by the motor generator, when the variable DF is switched from the opening degree on the valve opening side to the opening degree on the valve closing side, excessive acceleration due to the acceleration of the rotation speed of the turbine 6b is caused. Supply pressure is increased. As a result, when the operating state of the engine is within the range of the first mode region, the degree to which harmful gas is exhausted is reduced, and the responsiveness of the vehicle to the accelerator opening instructed by the driver (so-called It is possible to realize both driving operability, that is, improvement in drivability.

  If the engine operating state is not determined to be within the range of the mode range under the control of the ECU 20 as a result of the determination in step S502 described above through step S501 described above, in other words, the engine operating state is in the mode range. When it is determined that it is not within the range (step S502: No), switching from the opening on the valve opening side to the opening on the valve closing side is executed as a change in the opening of the variable diffuser 6n under the control of the ECU 20. In addition to this, acceleration of the rotational speed of the turbine 6b by the motor generator, that is, so-called motor-assisted turbocharging is executed (step S703).

  In particular, when the rotational speed of the turbine 6b is accelerated by the motor generator, when the variable DF is switched from the opening on the valve opening side to the opening on the valve closing side, the boost pressure is increased, and the intake air amount is increased. And the degree to which the air-fuel ratio becomes rich can be effectively reduced. As a result, it is possible to effectively reduce the degree to which harmful gas is exhausted by enrichment of the air-fuel ratio in the operating state outside the mode range. Alternatively, this makes it possible to effectively suppress fluctuations in the engine output torque and improve the driver's driving operability (so-called drivability) in the driving state outside the mode range.

(Eighth embodiment)
(Operating principle)
Next, control processing in the control apparatus for an internal combustion engine according to the eighth embodiment will be described with reference to FIGS. 21 and 22. FIG. 21 is a flowchart showing an operation flow in the control apparatus for an internal combustion engine according to the eighth embodiment. The operation shown in FIG. 21 is repeatedly executed at a predetermined cycle such as several microseconds. The components of the eighth embodiment are substantially the same as those of the fourth embodiment described above. In the eighth embodiment, the same step numbers are assigned to processes that are substantially the same as those of the fifth embodiment described above. These descriptions will be omitted as appropriate. FIG. 22 is a graph showing the operating state of the engine according to the eighth embodiment by the rotational speed of the engine and the output torque of the engine. In FIG. 22, the vertical axis represents the engine output torque (N · m: Newton meter), and the horizontal axis represents the engine rotation speed (rpm: revolution per minute).

  As a result of the determination in step S502 described above, when it is determined that the engine operating state is within the mode range under the control of the ECU 20 (step S502: Yes), the variable diffuser 6n is opened under the control of the ECU 20. As a change in the degree, switching from the opening on the valve opening side to the opening on the valve closing side, advance control for advancing the fuel injection timing, and shift by the continuously variable transmission are executed (step S801). ). Here, the “advance control for advancing the fuel injection timing” according to the present embodiment means that the fuel injection timing is advanced by a predetermined time from a reference timing that is a reference according to the running state of the vehicle. Means injection control. This predetermined time can be individually and specifically defined so as to increase the combustion pressure generated by the combustion of the fuel. The predetermined time may be defined by the engine rotation speed and the engine crank angle. Further, the shift by the continuously variable transmission according to the present embodiment is executed individually and specifically so as to reduce fluctuations in the engine output torque by the advance angle control for advancing the fuel injection timing.

  By increasing the combustion pressure of the fuel by the advance angle control for advancing the fuel injection timing, the opening degree on the valve closing side is changed from the opening degree on the variable diffuser 6n in the operating state of the mode region. The degree to which the air-fuel ratio becomes rich can be effectively reduced in accordance with the switching to. Thereby, the degree to which harmful gas is exhausted by enrichment of the air-fuel ratio can be effectively reduced. Here, the mode range according to the eighth embodiment means an operation state in which EGR is performed in the acceleration state of the vehicle. Typically, as shown in FIG. And the engine operating state in which the output torque of the engine is at a low level.

  On the other hand, as a result of the determination in the above-described step S502, when it is not determined that the engine operating state is within the mode range under the control of the ECU 20, in other words, the engine operating state is not within the mode range. When the determination is made (step S502: No), under the control of the ECU 20, the opening degree of the variable diffuser 6n is changed from the opening degree on the valve opening side to the opening degree on the valve closing side, and the stepless speed change. Shifting by the device is executed (step S802).

  In particular, the shift by the continuously variable transmission is executed individually and specifically so that the fluctuation of the output torque of the engine can be reduced when the engine is operating outside the mode range.

  Due to the speed change by the continuously variable transmission, the output torque of the engine fluctuates in accordance with the switching from the opening degree on the variable diffuser 6n to the opening degree on the valve closing side in the driving state outside the mode range. Can be effectively suppressed, and the driver's driving operability (so-called drivability) can be improved.

  As a result, when the engine is operating in the normal range, the degree to which harmful gas is exhausted is reduced, and the response of the vehicle to the accelerator opening instructed by the driver (so-called driving operability, that is, drivability) is improved. Improvement) can be realized.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and the control of the internal combustion engine accompanying such a change. The apparatus is also included in the technical scope of the present invention.

  The present invention is applicable to a control device for a compression ignition type internal combustion engine such as a diesel engine.

1 Engine 2 Electronic throttle valve 2a AFM (Air Flow Meter)
3 Intake passage 3M Intake manifold 4 Exhaust manifold 5 Intercooler 5f Air filter 6 for intake air filtration 6 Turbo supercharger 6a Compressor 6b Turbine 6m Motor generator 6n Variable diffuser 6s Angle sensor 7s Supercharging for measuring the supercharging pressure of the intake Pressure sensor 8 DPNR (Diesel Particulate-NOx active Reduction system) catalyst 9 Exhaust purification unit 10 Fuel addition valve 11 EGR passage 12 EGR catalyst 13 EGR cooler 14 EGR valve 15 Exhaust throttle valve 16 Muffler 20 ECU
30 Injector 31 Common rail 32 Fuel pump 33 Crank angle sensor 40 for measuring engine speed 40 Pressure sensor 50 Continuously variable transmission 70 Throttle valve 80 for adjusting intake air amount Variable valve mechanism 90 EGR passage
95 EGR valve 120 Compressor wheel 170 Movable vane mechanism 180 Movable vanes # 1 to # 4 Cylinder

Claims (4)

A movable vane having a turbine provided in the exhaust passage and a compressor provided in the intake passage, wherein the compressor can change the throttle amount of the flow path of the intake air sent from the compressor wheel by changing the position of the movable vane. A turbocharger provided with a mechanism;
Applied to an internal combustion engine with
A plurality of intake air amount correcting means for correcting the intake air amount of the internal combustion engine;
First determination means capable of determining whether or not to change the throttle amount based on the operating state of the internal combustion engine;
If it is determined that the throttle amount is to be changed, one of the plurality of types of intake air amount correcting means is selected based on the operating state of the internal combustion engine, and the selected one And a control means for correcting the intake air amount by the intake air amount correction means. A second determination means capable of determining whether or not the operating state of the internal combustion engine is an EGR operating state;
When it is determined that the throttle amount is to be changed, and when it is determined that the operating state is an EGR operating state, the plurality of types of intake air amount correcting units are based on the EGR operating state. 2. The control apparatus for an internal combustion engine according to claim 1, wherein any one of the intake air amount correcting means is selected, and the intake air amount is corrected by the selected one intake air amount correcting means. .   3. The control apparatus for an internal combustion engine according to claim 1, wherein the control means corrects the intake air amount by the selected intake air amount correction means simultaneously with the change of the throttle amount. As the plurality of types of intake air amount correction means,
A variable nozzle capable of changing the rotational speed of the turbine, a changing means for changing the throttle amount, a variable valve mechanism capable of changing the opening / closing timing of the intake valve of the internal combustion engine, and the rotational speed of the turbine can be changed The control device for an internal combustion engine according to any one of claims 1 to 3, comprising at least two of the motor generators.

Images