JP2010180831A - Control device for internal combustion engine - Google Patents

Abstract

An object of the present invention is to suppress the decrease in passenger comfort due to noise generated due to an increase in the rotational speed of a turbine, and to prevent white matter caused by the release of organic soluble components desorbed from an exhaust purification catalyst into the atmosphere. A control device for an internal combustion engine capable of suppressing the generation of smoke is provided.
An electronic control device estimates an amount of an organic soluble component adsorbed on an exhaust purification catalyst, and when the adsorbed amount of the estimated organic soluble component is large and the adsorbed amount is small. In addition, the exhaust flow rate increase control for increasing the flow rate of the exhaust gas passing through the exhaust purification catalyst 31 by reducing the amount of exhaust gas recirculated to the intake passage 20 through the exhaust gas recirculation mechanism 40 is executed. The electronic control unit 100 increases the opening degree of the nozzle vane 56 in the variable nozzle vane mechanism 54 when the flow rate of the exhaust gas passing through the exhaust purification catalyst 31 is increased through the exhaust gas flow rate increase control than when the exhaust gas flow rate is not increased. Also increase.
[Selection] Figure 1

Description

  This invention estimates the amount of adsorption of organic soluble components contained in the exhaust to the exhaust purification catalyst, and reduces the flow rate of exhaust gas recirculated to the intake passage according to the estimated amount of organic soluble components adsorbed. The present invention relates to a control device for an internal combustion engine that suppresses generation of white smoke.

  The exhaust of a diesel engine contains organic soluble components (SOF: Soluble Organic Fraction) derived from unburned fuel, evaporated lubricating oil, and the like. This organic soluble component is adsorbed to the exhaust purification catalyst when the temperature of the exhaust purification catalyst is low, and evaporates and desorbs from the exhaust purification catalyst when the temperature of the exhaust purification catalyst becomes high, so that it flows through the exhaust passage together with the exhaust. Become.

  At this time, if the exhaust contains a sufficient amount of oxygen with respect to the amount of the organic soluble component desorbed from the exhaust purification catalyst, the oxygen in the exhaust reacts with the organic soluble component. Organic soluble components are burned and removed in the exhaust passage. On the other hand, when the amount of oxygen contained in the exhaust gas is small relative to the amount of the organic soluble component desorbed from the exhaust purification catalyst, the organic soluble component desorbed from the exhaust purification catalyst is not completely burned, The remaining organic soluble components are cooled while flowing through the exhaust passage and become white smoke, which is released into the atmosphere.

  In order to suppress the generation of such white smoke, the control device for an internal combustion engine described in Patent Document 1 estimates the amount of organic soluble components adsorbed on the exhaust purification catalyst, and has a large amount of adsorption. On the basis of this, when it is estimated that white smoke may be generated when the organic soluble component is desorbed, the amount of exhaust gas recirculated to the intake passage through the exhaust gas recirculation mechanism is reduced.

  According to such a configuration, the amount of exhaust gas recirculated to the intake passage is reduced, thereby increasing the flow rate of exhaust gas introduced into the exhaust purification catalyst through the exhaust passage and increasing the amount of oxygen passing through the exhaust purification catalyst. To do. Therefore, according to the control device for an internal combustion engine described in Patent Document 1, it becomes possible to increase the amount of oxygen passing through the exhaust purification catalyst by reducing the flow rate of the exhaust gas recirculated to the intake passage. The generation of white smoke can be suppressed by promoting the reaction between the organic soluble component and the organic soluble component.

Japanese Patent Laid-Open No. 2005-23848

  Incidentally, a turbocharger is generally mounted on a diesel engine. In a diesel engine equipped with a turbocharger, when the amount of oxygen flowing through the exhaust passage is increased by reducing the exhaust gas recirculation amount as described above, the exhaust passage flows as the exhaust gas recirculation amount decreases. Since the flow rate of the exhaust gas increases and the flow rate of the exhaust gas blown to the turbine wheel increases, the rotational speed of the turbine increases. As a result, noise is generated as the rotational speed of the turbine increases, and passenger comfort may be impaired.

  The present invention has been made in view of the above circumstances, and the object thereof is to desorb from the exhaust purification catalyst while suppressing a decrease in passenger comfort due to noise generated due to an increase in the rotational speed of the turbine. An object of the present invention is to provide a control device for an internal combustion engine that can suppress the generation of white smoke due to the release of organic soluble components into the atmosphere.

In the following, means for achieving the above object and its effects are described.
According to the first aspect of the present invention, the amount of the organic soluble component adsorbed on the exhaust purification catalyst is estimated, and when the estimated amount of the organic soluble component adsorbed is large, the amount of the adsorbed amount is small. In a control device for an internal combustion engine that performs exhaust flow rate increase control for increasing the flow rate of exhaust gas that passes through the exhaust purification catalyst by reducing the amount of exhaust gas recirculated to the intake passage through an exhaust gas recirculation mechanism, the nozzle vane opening degree is A variable nozzle vane mechanism that adjusts the flow rate of the exhaust gas blown to the turbine wheel of the turbocharger by increasing or decreasing the exhaust gas flow rate when the flow rate of exhaust gas that passes through the exhaust purification catalyst is increased through the exhaust gas flow rate increase control. The gist of the invention is to increase the nozzle vane opening as compared to when the flow rate of the nozzle is not increased.

  According to the above configuration, when the flow rate of the exhaust gas recirculated to the intake passage is reduced and the flow rate of the exhaust gas passing through the exhaust purification catalyst is increased in order to suppress the generation of white smoke derived from organic soluble components, The nozzle vane opening degree of the variable nozzle vane mechanism is increased. As a result, even if the amount of exhaust gas recirculated to the intake passage is reduced and the flow rate of exhaust gas passing through the exhaust purification catalyst is increased, an increase in the flow rate of exhaust gas blown to the turbine wheel can be suppressed. The generation of noise due to the increase in the rotational speed of the turbine can be suppressed. That is, according to the configuration described in claim 1, the organic solubles desorbed from the exhaust purification catalyst while suppressing a decrease in passenger comfort due to noise caused by an increase in the rotational speed of the turbine. The generation of white smoke due to the release of components into the atmosphere can be suppressed.

  According to a second aspect of the present invention, in the control device for an internal combustion engine according to the first aspect, the flow rate of the exhaust gas passing through the exhaust purification catalyst is increased through the exhaust gas flow rate increase control on condition that the engine is in an idling operation state. The gist thereof is to increase the nozzle vane opening when the nozzle vane is being operated.

  The invention according to claim 3 is the control device for the internal combustion engine according to claim 2, wherein the idling operation state is determined based on the fact that the engine rotational speed is less than the reference rotational speed.

  The invention according to claim 4 is the control device for an internal combustion engine according to claim 2 or 3, wherein the idling operation state is determined based on the fact that the fuel injection amount is less than the reference injection amount. is there.

  When in a so-called idling operation state, which is a low-speed, low-load operation state, no road noise or wind noise due to traveling wind is generated, and noise associated with engine operation is small. The noise caused by the increase in the rotational speed of the vehicle is particularly audible to the passenger.

  Further, when the nozzle vane opening is increased, the flow rate of the exhaust gas blown to the turbine wheel is slowed down, so that turbo lag is likely to occur during acceleration, and drivability may be reduced due to a supercharging delay or the like. .

  In this regard, in the invention described in claim 2, the nozzle vane opening degree is increased on condition that the noise generated with the increase in the rotational speed of the turbine is in an idling operation state that is particularly audible to the passenger. I have to. According to such a configuration, the nozzle vane opening is increased only in the idling operation state in which the noise generated with the increase in the turbine rotation speed is easily heard by the passenger, and with the increase in the turbine rotation speed. Even when noise is generated, the nozzle vane opening is not increased in an operating state in which the noise is difficult for the passenger to hear. That is, according to the configuration described in 2 above, it is estimated that there is a high possibility that the comfort of the occupant is reduced due to noise generated with an increase in the rotational speed of the turbine based on the idling operation state, Based on this, the nozzle vane opening can be increased, and the decrease in comfort due to noise can be accurately suppressed while suppressing the decrease in drivability as much as possible.

  The idling operation state means that the engine rotational speed is lower than the reference rotational speed as in the configuration described in claim 3 above, or the fuel injection amount is the reference as in the configuration described in claim 4 above. It can be determined based on being less than the injection amount.

  The invention according to claim 5 calculates the basic nozzle vane opening based on the engine rotational speed and the fuel injection amount, calculates the correction coefficient based on the estimated adsorption amount of the organic soluble component, and A target nozzle vane opening is calculated by calculating a correction value based on the rotational speed and the fuel injection amount, and adding the correction amount to the basic nozzle vane opening as a correction amount obtained by multiplying the correction coefficient and the correction value. A control device for an internal combustion engine that feedback-controls a variable nozzle vane mechanism so that the nozzle vane opening coincides with the target nozzle vane opening, wherein the engine rotational speed is less than the reference rotational speed and the fuel injection amount is the reference injection A value other than “0” is set as the correction value corresponding to the idling operation region that is less than the amount, and the idling operation region is less than the idling operation region. A control device for an internal combustion engine according to claim 2, characterized in that to calculate the correction value by referring to calculation map "0" is set as the correction value corresponding to the operating region of.

  As a configuration for increasing the nozzle vane opening on condition that the engine is idling, the basic nozzle vane opening is calculated based on the engine speed and the fuel injection amount as described in claim 5 above. The correction coefficient is calculated based on the estimated adsorption amount of the organic soluble component, and the correction value is calculated based on the engine rotational speed and the fuel injection amount, and the correction coefficient and the correction value are multiplied. It is also possible to employ a configuration in which the target nozzle vane opening is calculated by adding the basic nozzle vane opening as a correction amount. In such a configuration, the correction value corresponding to the idling operation region in which the engine rotational speed is less than the reference rotational speed and the fuel injection amount is less than the reference injection amount as described in claim 5 is “0”. On the other hand, the correction value may be calculated with reference to the calculation map in which “0” is set as the correction value corresponding to the operation region other than the idling operation region.

  According to such a configuration, when the engine rotation speed is equal to or higher than the reference rotation speed, or when the fuel injection amount is equal to or higher than the reference injection amount, that is, when not in the idling operation state, “0” is referred to as the correction value, and correction is performed. The correction amount calculated by multiplying the coefficient and the correction value is set to “0”. That is, at this time, the nozzle vane opening degree is not increased. On the other hand, in the idling operation state, a value other than “0” is referred to as the correction value, and a value obtained by multiplying the correction value and the correction coefficient is calculated as a correction amount so that the nozzle vane opening is increased. Become. That is, according to the structure of the said Claim 5, the structure which increases a nozzle vane opening degree on the condition that it is an idling driving | running state is realizable.

  According to a sixth aspect of the present invention, in the control device for an internal combustion engine according to any one of the first to fifth aspects, the exhaust flow rate increase control is the same according to the estimated adsorption amount of the organic soluble component. As the amount of adsorption increases, the amount of exhaust gas to be recirculated decreases, and the control device for an internal combustion engine according to the present invention increases the amount of adsorption according to the estimated amount of adsorption of the organic soluble component. The gist is to increase the amount of increase when the nozzle vane opening is increased.

  When performing an exhaust flow rate increase control that reduces the amount of exhaust gas recirculated to the intake passage as the estimated amount of organic soluble component adsorption increases, the amount of estimated organic soluble component adsorption amount is large. The more the amount of exhaust blown to the turbine wheel increases. On the other hand, in the structure of the said Claim 6, the increase amount when increasing a nozzle vane opening degree is made large, so that the adsorption amount of the organic soluble component estimated is large. According to such a configuration, the larger the estimated amount of the organic soluble component adsorbed, that is, the amount of exhaust gas recirculated to the intake passage is greatly reduced, and the amount of exhaust gas blown to the turbine wheel becomes very large. The more this is estimated, the greater the nozzle vane opening. Therefore, even if the amount of exhaust gas blown to the turbine wheel is greatly increased on the basis of the estimated amount of adsorption of the organic soluble component, the nozzle vane opening degree is increased in a manner corresponding to the exhaust amount, and the turbine is suitably It is possible to suppress an increase in the rotation speed.

  The invention according to claim 7 is the control apparatus for an internal combustion engine according to any one of claims 1 to 6, wherein the amount of increase when the nozzle vane opening is increased is increased as the engine speed is lower. This is the gist.

  As the engine speed increases, mechanical noise and noise associated with engine combustion are more likely to be generated. Therefore, the noise associated with engine operation increases as the engine speed increases. On the other hand, in the configuration according to the seventh aspect, the amount of increase when the nozzle vane opening is increased is increased as the engine speed is lower. According to such a configuration, the nozzle vane opening degree is increased and the increase in the rotational speed of the turbine is suppressed as the engine rotational speed is lower and the noise associated with engine operation is estimated to be lower. In other words, the lower the noise associated with engine operation and the easier it is for the occupant to hear the noise due to the increase in the rotational speed of the turbine, the increase in the rotational speed of the turbine is suppressed, and the generation of noise is preferably suppressed. become.

  The invention according to claim 8 is the control apparatus for an internal combustion engine according to any one of claims 1 to 7, wherein the amount of increase when the nozzle vane opening is increased is increased as the fuel injection amount is smaller. This is the gist.

  The larger the fuel injection amount, the more intense the engine combustion, the higher the engine speed, and the greater the noise associated with engine operation. Therefore, even when the configuration in which the increase amount when the nozzle vane opening is increased as the fuel injection amount is small as in the invention described in claim 8 is adopted, As the noise caused by the increase in the rotational speed becomes more audible to the occupant, the increase in the rotational speed of the turbine is suppressed, and the noise caused by the increased rotational speed of the turbine reduces the comfort of the occupant. This can be suitably suppressed.

  According to a ninth aspect of the present invention, in the control device for an internal combustion engine according to any one of the first to eighth aspects, the amount of increase when the nozzle vane opening is increased is increased as the vehicle speed is lower. The gist.

  When the vehicle speed is low, road noise and wind noise due to traveling wind are reduced, and noise caused by an increase in the rotational speed of the turbine is easily heard by the occupant. Therefore, even when a configuration in which the amount of increase when the nozzle vane opening is increased is increased as the vehicle speed is lower and the increase in the rotational speed of the turbine is suppressed as in the invention described in claim 9 above, As in the seventh and eighth aspects, as the noise caused by the increase in the rotational speed of the turbine is more audible to the occupant, the increase in the rotational speed of the turbine is suppressed, which increases the rotational speed of the turbine. It can control suitably that the noise which originates reduces a passenger | crew's comfort.

The schematic diagram which shows schematic structure of the control apparatus of the internal combustion engine concerning one Embodiment of this invention, and the diesel engine which is a control object of the control apparatus. The schematic diagram which shows the operation | movement aspect of the variable nozzle vane mechanism of the turbocharger concerning the embodiment. The flowchart which shows the flow of a series of processes of the nozzle vane opening degree control concerning the embodiment. The calculation map of the basic nozzle vane opening degree in the nozzle vane opening degree control concerning the embodiment. The calculation map of the correction coefficient in the nozzle vane opening degree control concerning the embodiment. The calculation map of the correction value in the nozzle vane opening degree control concerning the embodiment. The graph which shows the relationship between the EGR valve opening degree reduced according to the adsorption amount of an organic soluble component, and a nozzle vane opening degree, and the relationship between these opening degree and turbine rotational speed.

  Hereinafter, an embodiment in which a control device for an internal combustion engine according to the present invention is embodied in an electronic control device for a diesel engine equipped with a turbocharger equipped with a variable nozzle vane mechanism will be described with reference to FIGS.

  FIG. 1 shows a schematic configuration of an electronic control device 100 according to the present embodiment and a diesel engine 10 that is a control target of the electronic control device 100. As shown in FIG. 1, an intake passage 20 and an exhaust passage 30 are connected to the diesel engine 10. An intake throttle valve 21 that is opened and closed by a motor 22 is provided in the intake passage 20, and the amount of air introduced into the combustion chamber 11 is adjusted by changing the opening of the intake throttle valve 21. .

  The combustion chamber 11 of the diesel engine 10 is provided with a fuel injection valve 12 for each cylinder. These fuel injection valves 12 are connected to a common rail 13 and inject fuel filled in the common rail 13 into the combustion chamber 11. The common rail 13 is supplied with fuel pumped from a fuel tank (not shown) and pumped by a supply pump 14.

  Further, as shown in FIG. 1, the intake passage 20 and the exhaust passage 30 are connected to a turbocharger 50. A turbine wheel 52 and a compressor wheel 53 are respectively provided at the end of the turbine 51 of the turbocharger 50. In the turbocharger 50, the exhaust gas flowing through the exhaust passage 30 is blown to the turbine wheel 52, whereby the turbine 51 rotates and the compressor wheel 53 rotates. As the compressor wheel 53 rotates, the air in the intake passage 20 is pressurized and fed into the combustion chamber 11.

  The turbocharger 50 of the present embodiment is provided with a variable nozzle vane mechanism 54 that adjusts the flow rate of exhaust gas blown to the turbine wheel 52. The variable nozzle vane mechanism 54 includes a nozzle vane 56 provided so as to surround the turbine wheel 52 and an actuator 55 that rotates the nozzle vane 56, and the actuator 55 changes the inclination of the nozzle vane 56. Thus, the flow rate of the exhaust gas blown to the turbine wheel 52 is adjusted.

  Specifically, as shown in FIG. 2, by rotating a plurality of nozzle vanes 56 provided so as to surround the turbine wheel 52 and changing the size of the gaps formed between the nozzle vanes 56, The flow rate of the exhaust gas blown to the turbine wheel 52 is adjusted. That is, when exhaust gas is introduced from the exhaust passage 30 through the scroll passage 57 as indicated by arrows in FIG. 2, each nozzle vane 56 is inclined toward the turbine wheel 52 side as indicated by a solid line in FIG. In this case, the gap formed between the nozzle vanes 56 becomes large, and the flow rate of the exhaust gas blown to the turbine wheel 52 becomes relatively slow. On the other hand, when each nozzle vane 56 is laid down in the circumferential direction of the scroll passage 57 as shown by a one-dot chain line in FIG. 2, the gap formed between the nozzle vanes 56 is reduced, and the turbine The flow rate of the exhaust gas blown to the wheel 52 increases.

  In the diesel engine 10 of the present embodiment, the turbo lag is reduced by operating the variable nozzle vane mechanism 54 and adjusting the flow velocity of the exhaust gas blown to the turbine wheel 52 in accordance with the engine operating state in this way. The output and drivability are improved.

  As shown in FIG. 1, an exhaust recirculation passage 41 that communicates with the intake passage 20 at a portion upstream of the turbocharger 50 in the exhaust passage 30 and recirculates part of the exhaust gas in the exhaust passage 30 to the intake passage 20. Is connected. The exhaust gas recirculation passage 41 is provided with an EGR valve 42 that is opened and closed by a linear solenoid 43. By changing the opening degree of the EGR valve 42, the exhaust gas recirculated from the exhaust passage 30 to the intake air passage 20 is provided. The quantity is metered. That is, the exhaust gas recirculation mechanism 40 is formed by the exhaust gas recirculation passage 41 and the EGR valve 42.

  Further, an exhaust purification catalyst 31 comprising a catalyst carrier carrying a NOx storage reduction catalyst and a diesel particulate filter is provided in a portion of the exhaust passage 30 downstream of the turbocharger 50.

  The above-described opening control of the EGR valve 42 in the exhaust gas recirculation mechanism 40, the opening control of the nozzle vane 56 in the variable nozzle vane mechanism 54, the opening control of the intake throttle valve 21, the control of the fuel injection amount Q by the fuel injection valve 12, etc. Various controls relating to the engine operation of the diesel engine 10 are executed by the electronic control unit 100. The electronic control device 100 includes a digital computer having a CPU, a ROM, a RAM, and the like, and a drive circuit for driving each device of the diesel engine 10.

  The electronic control device 100 includes an air flow meter 101 provided in the intake passage 20 for detecting the intake air amount GA and the outside air temperature THA, a rotational speed sensor 102 for detecting the engine rotational speed NE, and the amount of operation of the accelerator pedal by the driver. An accelerator position sensor 103 for detecting, a water temperature sensor 104 for detecting the engine cooling water temperature THW, and the like are connected. The output signals of these various sensors are taken into the electronic control device 100.

  The electronic control unit 100 adjusts the intake air amount GA through the opening degree control of the intake throttle valve 21 based on the output signals of these various sensors, and controls the fuel injection valve 12 to control the fuel injection timing and the fuel injection amount Q. To control. Further, the flow rate of the exhaust gas recirculated to the intake passage 20 through the exhaust gas recirculation mechanism 40 is adjusted by changing the opening degree of the EGR valve 42 and the opening degree of the intake throttle valve 21.

  By the way, the exhaust contains organic soluble components derived from unburned fuel, evaporated lubricating oil, and the like. The organic soluble component is adsorbed to the exhaust purification catalyst 31 when the temperature of the exhaust purification catalyst 31 is low, while evaporating and desorbing from the exhaust purification catalyst 31 when the temperature of the exhaust purification catalyst 31 becomes high, and the exhaust passage together with the exhaust. 30 will flow.

  At this time, if the exhaust gas contains a sufficient amount of oxygen with respect to the amount of the organic soluble component desorbed from the exhaust purification catalyst 31, the oxygen in the exhaust gas reacts with the organic soluble component. Thus, the organic soluble component burns in the exhaust passage 30. On the other hand, when the amount of oxygen contained in the exhaust gas is smaller than the amount of organic soluble components desorbed from the exhaust purification catalyst 31, the organic soluble components desorbed from the exhaust purification catalyst 31 are completely burned. Instead, the remaining organic soluble components are cooled while flowing through the exhaust passage 30 and become white smoke and are released into the atmosphere.

  In order to suppress the generation of such white smoke, the diesel engine 10 of this embodiment estimates the adsorption amount X of the organic soluble component adsorbed on the exhaust purification catalyst 31 as conventionally known. Based on the estimated adsorption amount X, exhaust flow rate increase control for reducing the opening degree of the EGR valve 42 of the exhaust gas recirculation mechanism 40 is executed.

  Specifically, the estimated adsorption amount X of the organic soluble component is equal to or greater than the reference adsorption amount Xst, and based on this, it is estimated that white smoke may be generated when the organic soluble component is desorbed. When the operation is performed, the opening of the EGR valve 42 is decreased, the amount of exhaust gas recirculated to the intake passage 20 is reduced, and the flow rate of exhaust gas introduced into the exhaust purification catalyst 31 through the exhaust passage 30 is increased. When such exhaust flow rate increase control is executed, the amount of oxygen passing through the exhaust purification catalyst 31 increases as the amount of exhaust gas introduced into the exhaust purification catalyst 31 increases. The reaction can be promoted to suppress the generation of white smoke.

  However, as described above, the turbocharger 50 is mounted on the diesel engine 10. When the exhaust gas flow rate increase control as described above is executed in the diesel engine 10 equipped with the turbocharger 50, it is sprayed on the turbine wheel 52 as the exhaust gas flow rate increases due to the opening degree of the EGR valve 42 being reduced. The flow rate of exhaust gas to be increased. As a result, the rotational speed of the turbine 51 increases, and the comfort of the occupant may be impaired by the noise generated therewith.

  Therefore, in the electronic control apparatus 100 of the present embodiment, the opening of the nozzle vane 56 is increased in conjunction with the reduction of the opening of the EGR valve 42 by the exhaust flow increase control, so that the turbine due to such an increase of the exhaust flow is obtained. An increase in the rotational speed of 51 is suppressed.

  Hereinafter, the opening degree control of the nozzle vane 56 in the diesel engine 10 of the present embodiment will be described with reference to FIG. FIG. 3 is a flowchart showing a flow of a series of processing for nozzle vane opening degree control according to the present embodiment.

This nozzle vane opening degree control is repeatedly executed at a predetermined control cycle by the electronic control unit 100 during engine operation in parallel with the above-described exhaust flow rate increase control.
When this control is started, the electronic control unit 100 first calculates a basic nozzle vane opening A based on the engine speed NE and the fuel injection amount Q in step S100 as shown in FIG. Here, the basic nozzle vane opening A is calculated with reference to a calculation map as shown in FIG.

  In this calculation map, the results of experiments and the like conducted in advance so that the optimum supercharging pressure for engine operation can be realized in each operation state as in the conventional nozzle vane opening control performed conventionally. The basic nozzle vane opening degree A is stored in advance with the engine speed NE and the fuel injection amount Q as parameters. Specifically, the value of the basic nozzle vane opening A becomes smaller as the engine speed NE is lower, and the value of the basic nozzle vane opening A becomes higher as the fuel injection amount Q is larger in the high rotation range. The values of the basic nozzle vane opening A with respect to the engine speed NE and the fuel injection amount Q are set so as to increase.

  In FIG. 4, the calculation map in the case where the engine rotational speed NE has m parameters from NE1 to NEm and the fuel injection amount Q has n parameters from Q1 to Qn. (M and n are positive integers). Therefore, in this calculation map shown in FIG. 4, a total of (m × n) values are stored as basic nozzle vane opening degree A values corresponding to respective parameter combinations. Thereby, for example, when the value of the engine rotational speed NE is NE1 and the value of the fuel injection amount Q is Q1, the value of A (NE1, Q1) is changed to the basic nozzle vane by referring to the calculation map of FIG. The opening degree A is calculated.

  When the basic nozzle vane opening A is calculated in step S100 with reference to the calculation map shown in FIG. 4, the electronic control unit 100 adsorbs the organic soluble component adsorption amount X estimated in the exhaust gas flow rate increase control in step S200. Is read.

The method of estimating the adsorption amount X in the exhaust flow rate increase control is as follows.
First, the temperature of the exhaust purification catalyst 31 is estimated based on the engine coolant temperature THW and the like, and the adsorption rate of the organic soluble component to the exhaust purification catalyst 31 is calculated based on the estimated temperature of the exhaust purification catalyst 31.

  Next, the amount of organic soluble components discharged from the combustion chamber 11 per unit time is estimated based on the engine speed NE and the fuel injection amount Q, and the exhaust purification catalyst 31 is determined based on the opening degree of the EGR valve 42 and the like. Calculate the amount of organic soluble component to reach. Then, by multiplying the adsorption rate by the amount of the organic soluble component reaching the exhaust purification catalyst 31 per unit time calculated in this way, the organic soluble component to the exhaust purification catalyst 31 per unit time is obtained. An adsorption rate, which is an adsorption amount, is calculated.

  Subsequently, the unit on the exhaust purification catalyst 31 based on the rate of reduction of organic soluble components (due to desorption and combustion) in the exhaust purification catalyst 31 estimated based on the temperature of the exhaust purification catalyst 31 and the adsorption rate. The rate of increase / decrease, which is the amount of increase / decrease in organic soluble components per hour, is calculated.

  Based on the speed of increase / decrease calculated in this way, the amount of increase / decrease of the organic soluble component is calculated for each predetermined calculation period, and by adding this, the amount X of adsorption of the organic soluble component to the exhaust purification catalyst 31 is calculated. Is estimated.

  In step S200, when the adsorption amount X of the organic soluble component estimated through the exhaust gas flow rate increase control as described above is read, the process proceeds to step S300, and the correction coefficient B is calculated based on the adsorption amount X. The calculation of the correction coefficient B is performed with reference to an operation map as shown in FIG.

  In this calculation map, the value of the correction coefficient B is stored as a function of the adsorption amount X so as to increase or decrease with the same tendency as the amount of decrease in the opening degree of the EGR valve 42 that is reduced in the exhaust flow rate increase control. Yes. Specifically, as shown in FIG. 5, when the adsorption amount X is less than the reference adsorption amount Xst and the opening degree of the EGR valve 42 is not reduced through the exhaust flow rate increase control, a value of “0” is set as the correction coefficient B. It has come to be referenced. On the other hand, when the adsorption amount X is equal to or larger than the reference adsorption amount Xst, the larger the adsorption amount X is referred to as the correction coefficient B so as to correspond to the reduction amount of the EGR valve 42 that increases as the adsorption amount X increases. It has come to be.

  In step S300, when the correction coefficient B is calculated based on the adsorption amount X, the process proceeds to step S400, and the electronic control unit 100 calculates the correction value C based on the engine speed NE and the fuel injection amount Q. The calculation of the correction value C is performed with reference to an operation map as shown in FIG.

In this calculation map, as shown in FIG. 6, the value of the correction value C is stored in advance with the engine speed NE and the fuel injection amount Q as parameters.
In FIG. 6, the calculation map has m parameters from NE1 to NEm for the engine speed NE and n parameters from Q1 to Qn for the fuel injection amount Q. (M and n are positive integers). In this calculation map, a total of (m × n) values are stored as the correction value C corresponding to each parameter combination. Thereby, in step S400, for example, when the value of the engine speed NE is NE1 and the value of the fuel injection amount Q is Q1, the value of C (NE1, Q1) is referred to with reference to the calculation map of FIG. Is calculated as the correction value C.

  In this calculation map, a value of “0” is calculated as the correction value C when the engine rotational speed NE is equal to or higher than the reference rotational speed NEst and when the fuel injection amount Q is equal to or higher than the reference injection amount Qst. Thus, the correction value C is set.

  Note that the reference engine speed NEst and the reference injection amount Qst are determined based on the fact that the engine rotation speed NE is less than the reference rotation speed NEst and the fuel injection amount Q is less than the reference injection amount Qst. The size is set so that it can be determined. That is, in the calculation map shown in FIG. 6, a value other than “0” is set as the correction value C only in the region corresponding to the idling operation state, and the correction value C is set in other regions. As a result, a value of “0” is set.

  In this calculation map, the correction value C set in the region corresponding to the idling operation state increases as the engine speed NE decreases and increases as the fuel injection amount Q decreases. Is set to

  When the correction value C is calculated with reference to the calculation map shown in FIG. 6, the process proceeds to step S500, and the target nozzle vane opening D is calculated based on the basic nozzle vane opening A, the correction coefficient B, and the correction value C. Specifically, a product obtained by multiplying the correction coefficient B and the correction value C is added to the basic nozzle vane opening A as a correction amount, and the value thus calculated is set as the target nozzle vane opening D.

  When the target nozzle vane opening degree D is thus calculated, the process proceeds to step S600, and the electronic control unit 100 controls the actuator 55 so that the opening degree of the nozzle vane 56 coincides with the target nozzle vane opening degree D, thereby reducing the opening degree of the nozzle vane 56. Feedback control. When the opening degree of the nozzle vane 56 is feedback-controlled in this way, the electronic control unit 100 once ends this series of processes.

  In the diesel engine 10 of the present embodiment, when the opening degree of the EGR valve 42 is reduced through the exhaust gas flow rate increase control by repeatedly executing the series of processes of the nozzle vane opening degree control as described above, At the same time, the opening degree of the nozzle vane 56 is increased.

  Hereinafter, the operation by increasing the opening degree of the nozzle vane 56 together with the reduction of the opening degree of the EGR valve 42 will be described with reference to FIG. FIG. 7 is a graph showing the relationship between the opening degree of the EGR valve 42 and the opening degree of the nozzle vane 56, which is reduced in accordance with the adsorption amount X of the organic soluble component, and the relation between the opening degree and the turbine rotation speed. It is.

  When it is determined that the amount X of the organic soluble component adsorbed on the exhaust purification catalyst 31 is greater than or equal to the reference adsorption amount Xst through the exhaust gas flow increase control, as the adsorption amount X increases as shown in the upper part of FIG. The opening degree of the EGR valve 42 is reduced. As a result, the amount of exhaust gas recirculated to the intake passage 20 decreases and the flow rate of exhaust gas passing through the exhaust purification catalyst 31 increases as shown in the second stage from the bottom of FIG.

As a result, the oxygen used for the reaction with the organic soluble component desorbed from the exhaust purification catalyst 31 is sufficiently supplied, and the generation of white smoke is suppressed.
At this time, when the opening degree of the nozzle vane 56 is not changed as shown by the broken line in the second stage from the top of FIG. 7, the flow rate of the exhaust gas blown to the turbine wheel 52 increases as the exhaust gas flow rate increases. Thus, as shown in the lower part of FIG. 7, the rotational speed of the turbine 51 is increased. As a result, noise is generated with the rotation of the turbine 51, and there is a possibility that the comfort of the passenger is impaired by this noise.

  On the other hand, as described above, in the nozzle vane opening degree control of the present embodiment, when the adsorption amount X of the organic soluble component estimated in the exhaust flow rate increase control is equal to or larger than the reference adsorption amount Xst, the correction coefficient The value of B is calculated based on the adsorption amount X. Further, at this time, in the idling operation state, the value of the correction value C is set to a value other than “0”, and a value obtained by multiplying the correction coefficient B and the correction value C is a basic nozzle vane opening degree as a correction amount. In addition to A, the opening degree of the nozzle vane 56 is increased. Therefore, in the nozzle vane opening degree control of the present embodiment, when in the idling operation state, the second stage from the top in FIG. 7 is indicated by a solid line as the opening degree of the EGR valve 42 is reduced by the exhaust flow rate increase control. Thus, the opening degree of the nozzle vane 56 is increased. As a result, even when the exhaust gas flow rate increases, it becomes possible to suppress an increase in the flow velocity of the exhaust gas blown to the turbine wheel 52, and as shown by the solid line in the lower stage of FIG. 7, the rotational speed of the turbine 51 increases. Can be suppressed.

According to the embodiment described above, the following effects can be obtained.
(1) When the opening degree of the EGR valve 42 is reduced through the exhaust gas flow rate increase control and the flow rate of the exhaust gas passing through the exhaust purification catalyst 31 is increased, the opening degree of the nozzle vane 56 of the variable nozzle vane mechanism 54 is increased. ing. Therefore, even if the flow rate of the exhaust gas that passes through the exhaust purification catalyst 31 increases as the opening degree of the EGR valve 42 decreases, an increase in the flow rate of the exhaust gas blown to the turbine wheel 52 can be suppressed. Thus, the generation of noise due to the increase in the rotational speed of the turbine 51 can be suppressed. That is, the organic soluble components desorbed from the exhaust purification catalyst 31 through the exhaust flow increase control are suppressed in the atmosphere while suppressing the passenger comfort from being lowered due to the noise caused by the increase in the rotational speed of the turbine 51. The generation of white smoke due to the emission can be suppressed.

  (2) A value other than “0” is set as the correction value C corresponding to the idling operation region in which the engine rotation speed NE is less than the reference rotation speed NEst and the fuel injection amount Q is less than the reference injection amount Qst. On the other hand, the correction value C is calculated with reference to a calculation map in which “0” is set as the correction value C corresponding to the operation region other than the idling operation region. Therefore, when the engine rotation speed NE is equal to or higher than the reference rotation speed NEst, or when the fuel injection amount Q is equal to or higher than the reference injection amount Qst, that is, when not in the idling operation state, “0” is referred to as the correction value C. The correction amount calculated by multiplying the correction coefficient B and the correction value C is set to “0”. On the other hand, in the idling operation state, a value other than “0” is referred to as the correction value C, a value obtained by multiplying the correction value C and the correction coefficient B is calculated as a correction amount, and the target nozzle vane opening degree D is calculated. Will be increased. That is, in the nozzle vane opening degree control of the present embodiment, the opening degree of the nozzle vane 56 is increased on condition that the idling operation state is set.

  During idling operation, road noise and wind noise due to traveling wind are not generated, and noise associated with engine operation is small. Therefore, noise caused by an increase in the rotational speed of the turbine 51 of the turbocharger 50 is low. Is easy for the passenger to hear.

  Further, when the opening degree of the nozzle vane 56 is increased, the flow rate of the exhaust gas blown to the turbine wheel 52 is slowed down, so that turbo lag is likely to occur during acceleration, and drivability is reduced due to a supercharging delay or the like. There is a fear.

  In this regard, as described above, in the nozzle vane opening degree control of the present embodiment, the nozzle vane 56 is provided on the condition that the noise generated with the increase in the rotational speed of the turbine 51 is in an idling operation state that is particularly audible to the passenger. The degree of opening is increased. According to such a configuration, the opening degree of the nozzle vane 56 is increased only in the idling operation state in which the noise generated with the increase in the rotation speed of the turbine 51 is easily heard by the occupant, and the rotation speed of the turbine 51 is reduced. Even when noise is generated along with the increase, the opening degree of the nozzle vane 56 is not increased in an operation state in which the noise is not easily heard by the occupant. That is, it is estimated that there is a high possibility that the comfort of the occupant is reduced due to the noise generated with the increase in the rotational speed of the turbine 51 based on the idling operation state, and the opening degree of the nozzle vane 56 is determined based on that. It becomes possible to increase, and it is possible to accurately suppress a decrease in comfort due to noise while suppressing a decrease in drivability as much as possible.

  (3) In the exhaust flow rate increase control of the present embodiment, the amount of decrease in the opening degree of the EGR valve 42 is increased as the estimated adsorption amount X of the organic soluble component is larger, and is returned to the intake passage 20. The amount of exhaust is reduced. Therefore, as the estimated amount of adsorption X increases, the amount of exhaust blown to the turbine wheel 52 increases. On the other hand, in the present embodiment, the larger the estimated amount X of the organic soluble component adsorbed, the larger the increase amount when increasing the opening of the nozzle vane 56, that is, the correction amount. Yes. Therefore, the larger the estimated amount X of the organic soluble component adsorbed, that is, the amount of exhaust gas recirculated to the intake passage 20 is greatly reduced, and the amount of exhaust gas blown to the turbine wheel 52 becomes very large. As the angle is estimated, the opening degree of the nozzle vane 56 is increased. Therefore, even if the amount of exhaust blown to the turbine wheel 52 is significantly increased based on the estimated amount of adsorption X, the opening degree of the nozzle vane 56 is increased in a manner corresponding to the amount of exhaust, and the turbine 51 is preferably An increase in rotation speed can be suppressed.

  (4) As described above, in the calculation map described with reference to FIG. 6, the correction value C in the idling operation region is set to a larger value as the engine speed NE is lower. Accordingly, during the idling operation, the correction amount of the opening degree of the nozzle vane 56 is increased as the engine rotational speed NE is lower, and the opening degree of the nozzle vane 56 is increased.

  As the engine rotational speed NE is higher, mechanical noise and noise associated with engine combustion are more likely to be generated. Therefore, the noise associated with engine operation increases as the engine rotational speed NE is higher. On the other hand, in the above embodiment, as the engine rotational speed NE is lower as described above, the increase amount when the opening degree of the nozzle vane 56 is increased, that is, the correction amount is increased. Therefore, as the engine rotational speed NE is lower and the noise associated with engine operation is estimated to be lower, the opening degree of the nozzle vane 56 is increased, and the increase in the rotational speed of the turbine 51 is suppressed. That is, as the noise associated with engine operation is small and the noise caused by the increase in the rotational speed of the turbine 51 is more audible to the occupant, the increase in the rotational speed of the turbine 51 is suppressed, and occurs as the rotational speed increases. It can suppress suitably that a passenger | crew's comfort is impaired by the noise to do.

  (5) Further, the larger the fuel injection amount Q, the more intense the engine combustion, the higher the engine speed NE, and the greater the noise associated with engine operation. On the other hand, in the calculation map described with reference to FIG. 6 as described above, the correction value C in the idling operation region is set to a larger value as the fuel injection amount Q is smaller. Therefore, the smaller the fuel injection amount Q, the larger the correction amount when increasing the opening of the nozzle vane 56. That is, as in the effect (4), the increase in the rotation speed of the turbine 51 is suppressed as the noise caused by the increase in the rotation speed of the turbine 51 becomes more audible to the passenger. It can suppress suitably that the noise resulting from the increase in rotational speed will reduce a passenger | crew's comfort.

In addition, the said embodiment can also be implemented with the following forms which changed this suitably.
A configuration in which the correction amount of the opening degree of the nozzle vane 56 is increased as the vehicle speed is lower and the increase in the rotational speed of the turbine 51 can be suppressed can be adopted. When the vehicle speed is low, road noise and wind noise due to traveling wind are reduced, and noise due to an increase in the rotational speed of the turbine 51 is easily heard by the occupant. Therefore, if the configuration in which the correction amount of the opening degree of the nozzle vane 56 is increased as the vehicle speed is low as described above, the vehicle speed is low and the noise caused by the increase in the rotational speed of the turbine 51 is more audible to the passenger. As a result, an increase in the rotational speed of the turbine 51 is suppressed, and noise caused by an increase in the rotational speed of the turbine 51 can be more suitably suppressed from deteriorating passenger comfort. .

  The content of the nozzle vane control exemplified in the above embodiment is an example of a configuration for increasing the opening degree of the nozzle vane 56 when the exhaust gas flow rate is increased through the exhaust flow rate increasing control, and the nozzle vane opening degree control. The contents of can be changed as appropriate.

  For example, in the nozzle vane control of the above embodiment, the basic nozzle vane opening A, the correction coefficient B, and the correction value C are calculated by referring to the calculation map. It is also possible to adopt a configuration in which the target nozzle vane opening degree D is calculated by sequentially calculating the value.

  In the above embodiment, when the engine rotation speed NE is equal to or higher than the reference rotation speed NEst and when the fuel injection amount Q is equal to or higher than the reference injection amount Qst, that is, in an operation region other than the idling operation region. The correction value C is calculated with reference to a calculation map in which a value of “0” is calculated as the correction value C. As a result, the opening degree of the nozzle vane 56 is increased only in the idling operation state. On the other hand, the correction value C may be calculated with reference to an operation map in which a value other than “0” is calculated even in an operation region other than the idling operation region. That is, you may make it increase the opening degree of the nozzle vane 56 also at times other than an idling driving | running state.

  In addition, when the configuration in which the correction value C is calculated with reference to the calculation map in which the correction value C is set to a value other than “0” even in an operation state other than the idling operation state as described above is employed. Even if it exists, the structure which determines whether it is an idling driving | running state separately and increases the opening degree of the nozzle vane 56 on condition that it is an idling driving | running state can also be employ | adopted. Specifically, it is determined whether or not the engine is in the idling operation state. When it is determined that the engine is in the idling operation state, the correction amount is reflected when the target nozzle vane opening degree D is calculated, and the nozzle vane 56 is opened. The degree may be increased.

  Note that the idling operation state can be determined based on the fact that the engine rotational speed NE is less than the reference rotational speed NEst and that the fuel injection amount Q is less than the reference injection amount NEst.

  If the flow rate of the exhaust gas recirculated to the intake passage 20 is reduced by reducing the opening degree of the EGR valve 42, the flow rate of the exhaust gas flowing through the exhaust passage 30 can be increased as long as the opening degree of the nozzle vane 56 is increased. An increase in the rotational speed of the turbine 51 due to the increase can be suppressed. Therefore, in order to suppress the generation of noise associated with the exhaust flow rate increase control, it is sufficient if the opening degree of the nozzle vane 56 is increased at least when the opening degree of the EGR valve 42 is reduced. Therefore, for example, when the opening degree of the EGR valve 42 is reduced through the exhaust flow rate increase control, the opening degree of the nozzle vane 56 is reduced by a predetermined amount regardless of the amount of the adsorption amount X, or the opening degree of the nozzle vane 56. It is also possible to adopt a configuration that increases the maximum opening degree.

  In addition, in the above embodiment, the exhaust flow rate increase control is executed to reduce the opening degree of the EGR valve 42 as the adsorption amount X is larger than the reference adsorption amount Xst and the adsorption amount X is larger. On the other hand, a configuration in which the present invention is applied is shown. On the other hand, the present invention is not limited to reducing the opening of the EGR valve 42 as the amount of adsorption X increases, but to increase the flow rate of exhaust gas in order to suppress the generation of white smoke due to organic soluble components. Any electronic control device that executes flow rate increase control can be applied. For example, the present invention is applied to one that executes exhaust flow rate increase control for reducing the opening degree of the EGR valve 42 by a certain amount when the adsorption amount X is equal to or larger than the reference adsorption amount Xst, and the opening degree of the EGR valve 42 is reduced. In some cases, the opening degree of the nozzle vane 56 may be increased by a certain amount.

DESCRIPTION OF SYMBOLS 10 ... Diesel engine, 11 ... Combustion chamber, 12 ... Fuel injection valve, 13 ... Common rail, 14 ... Supply pump, 20 ... Intake passage, 21 ... Intake throttle valve, 22 ... Motor, 30 ... Exhaust passage, 31 ... Exhaust purification catalyst 40 ... exhaust gas recirculation mechanism, 41 ... exhaust gas recirculation passage, 42 ... EGR valve, 43 ... linear solenoid, 50 ... turbocharger, 51 ... turbine, 52 ... turbine wheel, 53 ... compressor wheel, 54 ... variable nozzle vane mechanism, 55 DESCRIPTION OF SYMBOLS ... Actuator, 56 ... Nozzle vane, 57 ... Scroll path, 100 ... Electronic control unit, 101 ... Air flow meter, 102 ... Rotational speed sensor, 103 ... Accelerator position sensor, 104 ... Water temperature sensor.

Claims (9)

Estimate the amount of organic soluble component adsorbed on the exhaust purification catalyst. In a control device for an internal combustion engine that executes exhaust flow rate increase control for increasing the flow rate of exhaust gas that passes through the exhaust purification catalyst by reducing the amount of exhaust gas to be recirculated,
With a variable nozzle vane mechanism that adjusts the flow rate of the exhaust gas blown to the turbine wheel of the turbocharger by increasing or decreasing the nozzle vane opening,
An internal combustion engine characterized in that when the flow rate of exhaust gas passing through the exhaust purification catalyst is increased through the exhaust gas flow rate increase control, the nozzle vane opening is increased as compared with when the exhaust gas flow rate is not increased. Control device. The control apparatus for an internal combustion engine according to claim 1,
The control device for an internal combustion engine, wherein the nozzle vane opening is increased when the flow rate of exhaust gas passing through the exhaust gas purification catalyst is increased through the exhaust gas flow rate increase control on condition that the engine is in an idling operation state. . The control device for an internal combustion engine according to claim 2, wherein it is determined that the engine is in an idling operation state based on the fact that the engine rotational speed is less than the reference rotational speed. The control device for an internal combustion engine according to claim 2 or 3, wherein the idling operation state is determined based on the fuel injection amount being less than the reference injection amount. The basic nozzle vane opening is calculated based on the engine rotational speed and the fuel injection amount, the correction coefficient is calculated based on the estimated adsorption amount of the organic soluble component, and based on the engine rotational speed and the fuel injection amount. The target nozzle vane opening is calculated by adding a correction value to the basic nozzle vane opening as a correction amount obtained by multiplying the correction coefficient and the correction value. A control device for an internal combustion engine that feedback-controls a variable nozzle vane mechanism to match the opening degree,
A value other than “0” is set as the correction value corresponding to the idling operation region where the engine speed is less than the reference rotation speed and the fuel injection amount is less than the reference injection amount, and other than the idling operation region The control device for an internal combustion engine according to claim 2, wherein the correction value is calculated by referring to an arithmetic map in which “0” is set as the correction value corresponding to the operating region. The exhaust gas flow rate increase control is to reduce the amount of exhaust gas to be recirculated as the adsorption amount increases according to the estimated adsorption amount of the organic soluble component,
The internal combustion according to any one of claims 1 to 5, wherein an increase amount when the nozzle vane opening is increased is increased as the adsorption amount is increased in accordance with the estimated adsorption amount of the organic soluble component. Engine control device. In the control device for an internal combustion engine according to any one of claims 1 to 6,
A control device for an internal combustion engine, characterized in that an increase amount when the nozzle vane opening is increased is increased as the engine rotational speed is lower. In the control device for an internal combustion engine according to any one of claims 1 to 7,
The control apparatus for an internal combustion engine, wherein the amount of increase when the nozzle vane opening is increased is increased as the fuel injection amount is smaller. In the control device for an internal combustion engine according to any one of claims 1 to 8,
The control device for an internal combustion engine, wherein the amount of increase when the nozzle vane opening is increased is increased as the vehicle speed is lower.

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