JP4888368B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine, and more particularly to idle speed control (ISC) during no-load operation (idling) of an internal combustion engine applied to an automobile engine or the like. It is.

  Conventionally, in an internal combustion engine typified by an automobile engine, idle speed control (ISC) that maintains the engine speed at an appropriate value during no-load operation (during idling) has been performed.

In order to stabilize the engine rotational speed during idling, it is necessary to change the output torque of the engine during idling in accordance with fluctuations in the rotational speed. In order to change the output torque, a control method for advancing or retarding the ignition timing has been proposed. For example, Japanese Unexamined Patent Publication No. 2007-198356 (Patent Document 1) discloses a control device for an internal combustion engine that calculates idle torque using ignition efficiency corresponding to the ignition timing of the ignition device.
JP 2007-198356 A JP 2002-213292 A

  As a control of the output torque when the engine is idling, the ignition timing is retarded with respect to MBT (Minimum spark advance for Best Torque), and the ignition timing is advanced or retarded from the center. There is control for changing the output torque by making the angle. When the engine speed decreases, the torque is increased by advancing the ignition timing toward MBT. As a result, the engine speed increases. On the other hand, when the engine speed increases, the torque is reduced by retarding the ignition timing. As a result, the engine speed decreases. Such a series of controls makes it possible to stabilize the engine speed.

  However, fluctuations in engine rotation speed during idling may vary depending on the operating state of the engine at that time. For example, the operating state of the engine varies depending on the operating load of the air conditioner represented by the operation of the air compressor and the blower fan. In addition, the degree of fluctuation of the rotational speed may be different for each engine due to individual differences between engines. In order to increase or decrease the torque in consideration of such circumstances, it is conceivable that the ignition timing is advanced or retarded from the center with the ignition timing largely retarded with respect to MBT.

  On the other hand, fuel consumption generally decreases as the ignition timing is retarded from MBT. Therefore, it is not easy to satisfy both good responsiveness of torque control and improvement of fuel consumption. Japanese Patent Application Laid-Open No. 2007-198356 does not specifically show a solution to such a problem.

  An object of the present invention is to provide a control device for an internal combustion engine that can ensure the stability of the engine speed during idling and can improve fuel efficiency.

  In summary, the present invention is a control device for an internal combustion engine. The control device includes an idling control unit that controls output torque during idling of the internal combustion engine. The idling control unit controls the current ignition efficiency so that the current ignition efficiency of the internal combustion engine becomes equal to the target ignition efficiency, and increases the target ignition efficiency until the current ignition efficiency reaches a maximum value. And a target efficiency control unit that alternately executes a first process and a second process of changing the target ignition efficiency from the maximum value to a value lower by a predetermined amount after the current ignition efficiency reaches the maximum value.

Preferably, the target efficiency control unit changes the maximum value according to the load of the internal combustion engine.
Preferably, the target efficiency control unit changes the increase rate of the target ignition efficiency with respect to time according to the load of the internal combustion engine.

  Preferably, the target efficiency control unit decreases the ignition efficiency by increasing the charging efficiency of the internal combustion engine.

  More preferably, the ignition efficiency control unit smoothes the time variation of the target value of the output torque, outputs the target torque, the target torque from the smoothing unit, and the target ignition efficiency, And a filling efficiency calculation unit for calculating the filling efficiency.

  According to the present invention, it is possible to ensure the stability of the engine speed during idling and to improve fuel efficiency.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  As shown in FIG. 1, the vehicle on which the control device according to the present embodiment is mounted includes an engine 150, an intake system 152, an exhaust system 154, and an engine ECU 100. The engine 150 is a port injection type gasoline engine, but may include a direct injection injector that directly injects fuel into the cylinder instead of / in addition to the port injector.

  Intake system 152 includes an intake passage 110, an air cleaner 118, an air flow meter 104, a throttle motor 114, a throttle valve 112, and a throttle position sensor 116.

  The air taken in from the air cleaner 118 passes through the intake passage 110 and flows to the engine 150. A throttle valve 112 is provided in the middle of the intake passage 110. The throttle valve 112 is opened and closed when the throttle motor 114 is operated. At this time, the opening degree of the throttle valve 112 can be detected by the throttle position sensor 116. An air flow meter 104 is provided in the intake passage between the air cleaner 118 and the throttle valve 112, and detects the amount of intake air. The air flow meter 104 transmits an intake air amount signal representing the intake air amount Q to the engine ECU 100.

  Engine 150 includes a cooling water passage 122, a cylinder block 124, an injector 126, a piston 128, a crankshaft 130, a water temperature sensor 106, and a crank position sensor 132.

  The cylinder block 124 is provided with a cylinder corresponding to a specific number (the specific number corresponds to the number of cylinders), and each cylinder is provided with a piston 128. An air-fuel mixture of the fuel injected from the injector 126 and the sucked air is introduced into the combustion chamber above the piston 128 through the intake passage 110 and burned by ignition of a spark plug (not shown). When combustion occurs, the piston 128 is pushed down. At this time, the vertical motion of the piston 128 is converted into a rotational motion of the crankshaft 130 via the crank mechanism. Note that engine speed of engine 150 is detected by engine ECU 100 based on a signal detected by crank position sensor 132.

  A cooling water passage 122 is provided in the cylinder block 124, and the cooling water circulates by the operation of a water pump (not shown). The cooling water in the cooling water passage 122 flows to a radiator (not shown) connected to the cooling water passage 122 and is radiated by a cooling fan (not shown). A water temperature sensor 106 is provided on the cooling water passage 122 and detects the temperature (engine cooling water temperature) THW of the cooling water in the cooling water passage 122. Water temperature sensor 106 transmits a signal indicating detected engine cooling water temperature THW to engine ECU 100.

  Exhaust system 154 includes an exhaust passage 108, a first air-fuel ratio sensor 102A, a second air-fuel ratio sensor 102B, a first three-way catalytic converter 120A, and a second three-way catalytic converter 120B. A first air-fuel ratio sensor 102A is provided on the upstream side of the first three-way catalytic converter 120A, and the second is provided on the downstream side of the first three-way catalytic converter 120A (upstream side of the second three-way catalytic converter 120B). The air-fuel ratio sensor 102B is provided. One three-way catalytic converter may be used.

  The exhaust passage 108 connected to the exhaust side of the engine 150 is connected to the first three-way catalytic converter 120A and the second three-way catalytic converter 120B. That is, the exhaust gas generated by the combustion of the air-fuel mixture in the combustion chamber in the engine 150 first flows into the first three-way catalytic converter 120A. HC and CO contained in the exhaust gas flowing into the first three-way catalytic converter 120A are oxidized in the first three-way catalytic converter 120A. Further, NOx contained in the exhaust gas flowing into the first three-way catalytic converter 120A is reduced in the first three-way catalytic converter 120A. The first three-way catalytic converter 120A is installed in the vicinity of the engine 150, and even when the engine 150 is cold-started, the temperature is quickly raised to exhibit a catalytic function.

  Further, the exhaust gas is sent from the first three-way catalytic converter 120A to the second three-way catalytic converter 120B for the purpose of purifying NOx. The first three-way catalytic converter 120A and the second three-way catalytic converter 120B basically have the same structure and function.

  First air-fuel ratio sensor 102A provided upstream of first three-way catalytic converter 120A, provided downstream of first three-way catalytic converter 120A and upstream of second three-way catalytic converter 120B The second air-fuel ratio sensor 102B thus detected detects the concentration of oxygen contained in the exhaust gas that has passed through the first three-way catalytic converter 120A or the second three-way catalytic converter 120B. By detecting the oxygen concentration, it is possible to detect the so-called air-fuel ratio of the fuel and air contained in the exhaust gas.

  The first air-fuel ratio sensor 102A and the second air-fuel ratio sensor 102B generate a current corresponding to the oxygen concentration in the exhaust gas. This current is converted into a voltage, for example, and input to engine ECU 100. Therefore, the air-fuel ratio of the exhaust gas upstream of the first three-way catalytic converter 120A can be detected from the output signal of the first air-fuel ratio sensor 102A, and the second output signal from the second air-fuel ratio sensor 102B can be detected. The air-fuel ratio of the exhaust gas upstream of the three-way catalytic converter 120B can be detected. The first air-fuel ratio sensor 102A and the second air-fuel ratio sensor 102B generate, for example, a voltage of about 0.1 V when the air-fuel ratio is lean, and a voltage of about 0.9 V when the air-fuel ratio is rich. It is what happens. A value converted into an air-fuel ratio based on these values is compared with an air-fuel ratio threshold value, and air-fuel ratio control by engine ECU 100 is performed.

  The first three-way catalytic converter 120A and the second three-way catalytic converter 120B function to reduce NOx while oxidizing HC and CO when the air-fuel ratio is substantially the stoichiometric air-fuel ratio, that is, simultaneously perform HC, CO, and NOx. Has the function of purifying. In these first three-way catalytic converter 120A and second three-way catalytic converter 120B, if the air-fuel ratio is lean and the amount of oxygen in the exhaust gas is large, the oxidizing action becomes active but the reducing action becomes inactive. If the air-fuel ratio is rich and the amount of oxygen in the exhaust gas is small, the reduction action becomes active, but the oxidation action becomes inactive, and all the above three components cannot be purified well.

  The engine ECU 100 is connected to an accelerator pedal opening sensor 160 that detects the opening of the accelerator pedal (accelerator pedal opening ACC) operated by the driver.

  The engine ECU 100 uses the relationship among the engine speed NE, the charging efficiency KL, the ignition timing SA, the air-fuel ratio A / F (here, assuming stoichiometric) and the torque so that the target torque can be realized. The opening degree, the ignition timing, and the fuel injection amount are calculated, and the opening degree of the throttle valve 112, the ignition timing, and the fuel injection amount from the injector 126 (more specifically, the fuel injection time and the injected fuel amount are linear. In a region where the relationship is established (injection amount limit region), the engine ECU 100 controls the fuel injection time to control the fuel injection amount).

  The engine 150 is connected to an accessory device group configured to obtain operating energy by the rotational force of the engine 150. A typical example of the accessory device is an air conditioner 180. The air conditioner device 180 is inputted with operation instructions such as an on / off instruction and a set temperature. The engine ECU 100 is further input with load request information of the accessory device group represented by the air conditioner device 180.

  With reference to FIG. 2, a functional block diagram of the control device according to the present embodiment will be described. As shown in FIG. 2, this control device (implemented by engine ECU 100) includes an arithmetic unit 1000, a KL calculator 1010, a throttle calculator 1030, an ignition timing calculator 2000, and a target efficiency controller 3000. including. The calculator 1000, the KL calculator 1010, the throttle calculator 1030, and the ignition timing calculator 2000 are shown in FIG. 2 as one example for specifically realizing the “ignition efficiency controller” in the present invention. It is a thing.

  The arithmetic unit 1000 calculates a torque (hereinafter referred to as a maximum efficiency torque) by dividing a target torque at the time of ISC (Idle Speed Control) (hereinafter sometimes referred to as ISC target torque) by a target ignition efficiency. In the present embodiment, the maximum efficiency torque is, for example, torque when the ignition efficiency is 1.0 (in other words, torque when the ignition timing is MBT).

  The KL calculator 1010 calculates a target KL (target charging efficiency) based on the maximum efficiency torque calculated by the calculator 1000 and the engine speed NE (current engine speed).

  The throttle calculation unit 1030 calculates the opening of the throttle valve 112 (hereinafter sometimes referred to as the throttle opening) based on the target KL.

  Further, the current charging efficiency KL (hereinafter sometimes referred to as “current KL”) is detected, and the ignition timing calculation unit 2000 detects the engine speed NE (current engine speed), the current KL, The ignition timing is calculated based on the ISC target torque.

  The target efficiency control unit 3000 calculates the target ignition efficiency based on the current KL, the current NE, and the ignition timing calculated by the ignition timing calculation unit 2000, and outputs the calculated target ignition efficiency to the calculator 1000.

  Such a control apparatus according to the present embodiment is read out from the CPU (Central Processing Unit) and the memory included in the engine ECU 100 and executed by the CPU even in hardware mainly composed of a digital circuit or an analog circuit. It can also be realized by software mainly composed of programs to be executed. In general, it is said that it is advantageous in terms of operation speed when realized by hardware, and advantageous in terms of design change when realized by software. Below, the case where a control apparatus is implement | achieved as software is demonstrated.

  FIG. 3 is a flowchart showing a calculation process of the ignition timing by the control device shown in FIG. The process shown in this flowchart is called from the main routine and executed when, for example, a predetermined condition is satisfied or at regular intervals.

  3 and FIG. 2, when the process is started, in step S1, ignition timing calculation unit 2000 calculates target ignition efficiency used for calculating the ignition timing. Specifically, ignition timing calculation unit 2000 calculates the target ignition efficiency by dividing the target torque by the maximum efficiency torque determined from the current operating state of engine 150. The maximum efficiency torque is obtained from the current NE and the current KL.

  In step S2, the ignition timing calculation unit 2000 determines whether or not the target ignition efficiency calculated in step S1 is greater than the maximum efficiency. As described above, in this embodiment, the maximum efficiency is set to 1.0. If the target ignition efficiency is equal to or less than the maximum efficiency (NO in step S2), the process proceeds to step S4 described later.

  If the target ignition efficiency is greater than the maximum efficiency (YES in step S2), ignition timing calculation unit 2000 performs a guard process in step S3. Specifically, the ignition timing calculation unit 2000 replaces the target ignition efficiency calculated in step S1 with the maximum efficiency (step S3). Thus, the target ignition efficiency is controlled so as not to exceed the maximum efficiency.

  For example, when the engine speed rapidly decreases, it is considered that control for rapidly increasing the target torque is performed in order to return the engine speed to the original speed. In this case, the target torque may exceed the maximum efficiency. However, even if the target torque is rapidly increased, there is a high possibility that a sufficient amount of air is not supplied to the engine to output the target torque from the engine. By controlling the target ignition efficiency so as not to exceed the maximum efficiency, the engine output torque is limited to be equal to or less than the maximum torque that the engine can output at the present time.

  In step S4, the ignition timing calculation unit 2000 calculates the ignition timing (SA) based on the target ignition efficiency calculated in step S1 (or the target ignition efficiency subjected to the guard process in step S3). Specifically, the ignition timing calculation unit 2000 stores in advance a map in which the target ignition efficiency and the ignition timing are associated with each other. This map is determined on the basis of the relationship between the target ignition efficiency and the ignition timing obtained by, for example, experiments. The ignition timing calculation unit 2000 calculates the ignition timing (SA) from the calculated target ignition efficiency and the map. When the process of step S4 ends, the entire process returns to the main routine.

  FIG. 4 is a flowchart showing a calculation process of the throttle opening by the control device shown in FIG. The process shown in this flowchart is called from the main routine and executed when, for example, a predetermined condition is satisfied or at regular intervals.

  Referring to FIGS. 4 and 2, when the process is started, computing unit 1000 calculates a maximum efficiency torque in step S11. Specifically, computing unit 1000 calculates the maximum efficiency torque by dividing the target torque by the target ignition efficiency.

  In step S12, the KL calculator 1010 calculates a target KL. Specifically, the KL calculator 1010 stores in advance a map for converting the current NE and the maximum efficiency torque into the target KL. This map is obtained in advance by, for example, experiments. Then, the KL calculator 1010 calculates the target KL from this map, the current NE, and the maximum efficiency torque calculated in step S11.

  In step S13, the throttle calculation unit 1030 receives the target KL calculated by the KL calculator 1010. Then, the throttle calculation unit 1030 calculates the throttle opening by substituting the target KL into a throttle opening conversion formula stored in advance. When the process of step S13 ends, the entire process returns to the main routine.

  The target ignition efficiency in step S11 is determined based on the flowchart shown in FIG. The process shown in this flowchart is called and executed from the main routine, for example, when a predetermined condition is satisfied or at regular intervals.

  Referring to FIGS. 5 and 2, when the process is started, in step S21, target efficiency control unit 3000 calculates the current ignition efficiency. Specifically, the target efficiency control unit 3000 calculates the current ignition efficiency by dividing the current torque by the maximum efficiency torque. Target efficiency control unit 3000 calculates the maximum efficiency torque based on the current rotational speed of engine 150 and the current charging efficiency. The target efficiency control unit 3000 calculates the current torque based on the calculated maximum efficiency torque (that is, the current maximum efficiency torque) and the ignition timing calculated by the ignition timing calculation unit 2000 immediately before the calculation of the maximum efficiency torque. To do.

  In step S22, target efficiency control unit 3000 determines whether or not the current ignition efficiency is smaller than the maximum efficiency (1.0 in the present embodiment).

  When the current ignition efficiency is smaller than the maximum efficiency (YES in step S22), the target efficiency control unit 3000 displays the current target ignition efficiency (shown as “target ignition efficiency (n)” in the drawing) at the previous time. Calculation is performed by adding α to the target ignition efficiency calculated by the calculation process (shown as “target ignition efficiency (n−1)” in the figure) (step S23). In this embodiment, α is a constant value.

  On the other hand, when the current ignition efficiency is equal to the maximum efficiency (NO in step S22), target efficiency control unit 3000 calculates the current target ignition efficiency (target ignition efficiency (n)) by the previous calculation process. It is calculated by subtracting β from the target ignition efficiency (target ignition efficiency (n−1)) (step S24). In this embodiment, β is a constant value.

  When the process of step S23 or step S24 ends, the entire process returns to the main routine.

  The processing shown in the flowchart of FIG. 5 will be described more specifically. First, the target efficiency control unit 3000 increases the target ignition efficiency by α until the current ignition efficiency reaches the maximum efficiency. As a result, the current ignition timing is advanced. Therefore, the current ignition efficiency increases and approaches the maximum efficiency (step S23).

  Next, the current ignition efficiency is equal to the maximum efficiency. Then, the KL calculator 1010 increases the target filling efficiency. As a result, the target ignition efficiency becomes a value lower than the maximum efficiency by a predetermined amount β. Therefore, the current ignition efficiency is also lower than the maximum efficiency (step S24). After the process of step S24, the process of step S23 is performed again. That is, the process of step S23 and the process of step S24 are executed alternately, and the current ignition efficiency changes repeatedly between the maximum efficiency and a value lower by β than the maximum efficiency.

  Note that the flowcharts shown in FIGS. 3 to 5 may be executed in parallel, or include steps S1 to S4 (FIG. 3), steps S11 to S13 (FIG. 4), and steps S21 to S24 (FIG. 5). ) In this order.

  FIG. 6 is a diagram for explaining control of ignition timing, throttle opening, and ignition efficiency according to the present embodiment.

  Referring to FIGS. 6 and 2, target efficiency control unit 3000 increases target ignition efficiency by α per unit time until target ignition efficiency reaches the maximum value. The target ignition efficiency reaches the maximum value at time to. Then, the target efficiency control unit 3000 decreases the target ignition efficiency by β from the maximum value. Then, the target efficiency control unit 3000 increases at a rate of α per unit time until the maximum value is reached again. This process corresponds to the process shown in the flowchart of FIG.

  By increasing the target ignition efficiency, the current ignition efficiency is increased and the ignition timing is advanced. At time to, the actual ignition efficiency reaches the maximum value, and the ignition timing becomes the maximum efficiency timing (for example, MBT). In this case, the target torque is equal to the maximum efficiency torque (that is, the maximum torque).

  Prior to time to, the maximum efficiency torque (target torque ÷ target ignition efficiency) decreases as the target ignition efficiency increases. As a result, the target charging efficiency calculated by the KL calculator 1010 also decreases. As the target KL decreases, the current charging efficiency and throttle opening also decrease.

  When the target ignition efficiency reaches the maximum value, the target torque becomes equal to the maximum efficiency torque. Next, when the target ignition efficiency decreases by β from the maximum value, the target charging efficiency calculated by the KL calculator 1010 increases. Therefore, the current charging efficiency and the throttle opening also increase. This reduces the current ignition efficiency and retards the ignition timing from the maximum efficiency timing.

  As the target ignition efficiency increases after time to, the current ignition efficiency increases and the ignition timing also advances. That is, the control before time to is repeated after time to.

  As described above, in the present embodiment, the first process of increasing the target ignition efficiency until the current ignition efficiency reaches the maximum value, and the target ignition efficiency from the maximum value after the current ignition efficiency reaches the maximum value. The second process of changing to a lower value by a predetermined amount is repeated alternately. By bringing the target ignition efficiency close to the maximum efficiency, the current ignition efficiency approaches the maximum value (the ignition timing is advanced), so the engine output torque increases. By changing the target ignition efficiency from the maximum value to a value lower by a predetermined amount after the current ignition efficiency reaches the maximum value, the output torque of the engine is reduced. By repeating the first and second processes, the engine output torque is repeatedly increased and decreased. As a result, the engine speed during idling can be stabilized.

  In the present embodiment, so-called control is performed so that the current ignition efficiency is always close to the maximum value. As a result, fuel consumption can be prevented from decreasing.

  Furthermore, in the present embodiment, the engine output torque is increased by bringing the current ignition efficiency close to the maximum value. This makes it possible to quickly increase the engine output torque. Therefore, good responsiveness of torque control can be realized.

(Modification 1)
In this modification, the target efficiency control unit 3000 shown in FIG. 2 changes the maximum value of the target ignition efficiency in accordance with the engine load (operating state). For example, the engine load may be different between a state where the air conditioner device is operating and a state where the air conditioner device is stopped. By changing the maximum value of the target ignition efficiency according to the engine load, the engine speed during idling can be stabilized even if the engine load changes.

  Note that the ignition timing calculation unit 2000 determines whether or not the current ignition efficiency is greater than the maximum efficiency (see FIG. 5). For example, the ignition timing calculation unit 2000 can obtain the maximum efficiency value necessary for the determination by receiving the maximum efficiency value from the target efficiency control unit 3000. It should be noted that the ignition timing calculation unit 2000 also receives the value of the maximum efficiency from the target efficiency control unit 3000 in each modification described below.

  FIG. 7 is a diagram illustrating an example of the relationship between the engine load and the maximum value (maximum efficiency) of ignition efficiency. Referring to FIGS. 7 and 2, target efficiency control unit 3000 determines whether the engine load level is large, medium, or small based on load request information from the air conditioner. Then, target efficiency control unit 3000 determines the maximum efficiency according to the determined degree of engine load. For example, the maximum efficiency when the engine load is large is 1.0, the maximum efficiency when the engine load is medium is 0.97, and the maximum efficiency when the engine load is small is 0. 95.

  For example, when the operating load of the air conditioner is maximum, it is considered that the possibility that the engine load becomes larger than the current load is low. Therefore, in this case, the maximum efficiency is set to a value (1.0) when the degree of engine load is large.

  For example, if the air conditioner is currently operating but its operating load is not the maximum, the operating load of the air conditioner may increase in the future. Therefore, the maximum efficiency in this case is set to a value (0.97) when the engine load is medium.

  For example, if the air conditioner device is currently stopped, the air conditioner device may operate in the future. Therefore, the maximum efficiency in this case is set to a value (0.95) when the degree of engine load is small.

(Modification 2)
In the second modification, similarly to the first modification, the maximum value of the target ignition efficiency is changed according to the engine load (operating state). In the following, fluctuations in the operating load of the air conditioner will be shown as an example of factors that cause fluctuations in the engine load.

  FIG. 8 is a diagram illustrating an example of a change in the maximum value (maximum efficiency) of the ignition efficiency accompanying the operation of the air conditioner device.

  Referring to FIGS. 8 and 2, target efficiency control unit 3000 sets the maximum efficiency value to 0.95 when the air conditioner is stopped (OFF state). At time t1, the operation of the air conditioner is started, and the air conditioner is turned on. At this time, the target efficiency control unit 3000 increases the maximum efficiency value from 0.95 to 1.0. After the time t1, the target efficiency control unit 3000 gradually decreases the maximum efficiency value from 1.0. Note that the maximum efficiency value finally becomes a value (for example, 0.97) corresponding to the operating load of the air conditioner.

  Regardless of the operating load of the air conditioner, the engine speed may drop rapidly at the start of the operation of the air conditioner. For this reason, in the second modification, the maximum efficiency is once increased in accordance with the start of the operation of the air conditioner. And target efficiency control part 3000 sets the maximum efficiency according to the operation load of an air-conditioner device when operation of an air-conditioner device is stabilized by decreasing the maximum efficiency moderately. As a result, similarly to the first modification, even when the engine load changes, the engine speed during idling can be stabilized.

(Modification 3)
In the third modification, the target efficiency control unit 3000 changes the increment value (that is, α) of the target ignition efficiency per unit time in accordance with the engine load (operating state).

  FIG. 9 is a diagram showing a change over time in target ignition efficiency when the engine load (operating state) is in a predetermined state.

  Referring to FIG. 9, the target ignition efficiency (shown as “target efficiency” in the figure) changes with period T. The period T is appropriately determined within a range of several seconds to several tens of seconds, for example.

  FIG. 10 is a diagram showing a change over time in the target ignition efficiency when the increment value of the target ignition efficiency becomes small.

  Referring to FIG. 10, the change over time in target ignition efficiency indicated by the solid line corresponds to the change over time in target ignition efficiency shown in FIG. The time change of the target ignition efficiency indicated by the broken line is a value obtained by decreasing the increment value per unit time of the target ignition efficiency smaller than the time change of the target ignition efficiency indicated by the solid line. The period T1 of the change over time of the target ignition efficiency indicated by the broken line is longer than the period T.

  FIG. 11 is a diagram showing a change over time in the target ignition efficiency when the increment value of the target ignition efficiency becomes large.

  Referring to FIG. 11, the change over time in target ignition efficiency indicated by the solid line corresponds to the change over time in target ignition efficiency shown in FIG. The time change of the target ignition efficiency indicated by the broken line is a value obtained by increasing the increment value per unit time of the target ignition efficiency, compared to the time change of the target ignition efficiency indicated by the solid line. The period T2 of the change over time of the target ignition efficiency indicated by the broken line is shorter than the period T.

  The target efficiency control unit 3000 shown in FIG. 2 realizes the time change of the target ignition efficiency indicated by the broken line in FIG. 11 when the engine load increases (for example, the operating load of the air conditioner becomes maximum). To change the target ignition efficiency. On the other hand, when the engine load decreases (for example, the air conditioner stops), target efficiency control unit 3000 changes the target ignition efficiency so that the change over time of target ignition efficiency indicated by the broken line in FIG. 10 is realized. Let The target efficiency control unit 3000 changes the target ignition efficiency so that the change in the target ignition efficiency shown in FIG. 9 is realized when, for example, the air conditioner operates but the operating load is not maximum. .

  Thus, in the third modification, the increment value (that is, α) of the target ignition efficiency per unit time is changed according to the engine load (operating state). As a result, the output torque can be quickly increased when the current load is large, and the output torque can be gradually increased when the current load is not so large. As a result, it is possible to appropriately change the engine output torque according to the current load, and to suppress a reduction in fuel consumption.

(Modification 4)
FIG. 12 is a functional block diagram showing a configuration of a control device according to the fourth modification.

  Referring to FIG. 12, the control device is different from the control device shown in FIG. 2 in that it further includes a smoothing unit 1040 that is provided in the preceding stage of computing unit 1000 and smoothes the temporal variation of the ISC target torque.

  The ISC target torque may vary finely depending on the engine load. As shown in the flowchart of FIG. 4, the throttle opening is determined by the maximum efficiency torque obtained from the target torque (ISC target torque) and the target ignition efficiency. Therefore, when the ISC target torque varies finely, the throttle opening calculated by the throttle calculation unit 1030 also varies finely. In order to realize the calculated throttle opening, the throttle motor 114 shown in FIG. 1 changes the opening of the throttle valve 112 in small increments. In this case, for example, the influence on the durability of the throttle valve can be considered.

  In Modification 4, for example, as shown in FIG. 13, the smoothing processing unit 1040 smoothes the time variation of the target torque. Thereby, for example, even if an irregular time change occurs in the target torque before smoothing, the value of the target torque after smoothing can be stabilized at a certain value. As a result, for example, problems caused by fine fluctuations in the throttle opening (for example, influence on the durability of the throttle valve) can be prevented.

  In addition, the smoothing process by the smoothing process part 1040 is not limited to a specific process. An example of the smoothing process includes, for example, a process for calculating a time average, a primary filter process, a smoothing process, a hysteresis process, and the like.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is a control block diagram of a vehicle on which a control device according to an embodiment of the present invention is mounted. It is a control block diagram of the control apparatus which concerns on embodiment of this invention. 3 is a flowchart showing a calculation process of ignition timing by the control device shown in FIG. 2. It is a flowchart which shows the calculation process of the throttle opening by the control apparatus shown in FIG. 3 is a flowchart showing a calculation process of target ignition efficiency by the control device shown in FIG. 2. It is a figure for demonstrating control of the ignition timing according to this Embodiment, throttle opening, and ignition efficiency. It is a figure which shows an example of the relationship between the engine load and the maximum value (maximum efficiency) of ignition efficiency. It is a figure which shows an example of the change of the maximum value (maximum efficiency) of the ignition efficiency accompanying operation | movement of an air-conditioner apparatus. It is a figure which shows the time change of the target ignition efficiency in case an engine load (operation state) is a predetermined state. It is a figure which shows the time change of target ignition efficiency when the increment value of target ignition efficiency becomes small. It is a figure which shows the time change of target ignition efficiency when the increment value of target ignition efficiency becomes large. It is a functional block diagram which shows the structure of the control apparatus according to the modification 4. It is a figure explaining the smooth process of the target torque by the smooth process part 1040 shown in FIG.

Explanation of symbols

  100 Engine ECU, 102A, 102B Air-fuel ratio sensor, 104 Air flow meter, 106 Water temperature sensor, 108 Exhaust passage, 110 Intake passage, 112 Throttle valve, 114 Throttle motor, 116 Throttle position sensor, 118 Air cleaner, 120A, 120B Three-way catalyst Converter, 122 Cooling water passage, 124 Cylinder block, 126 Injector, 128 Piston, 130 Crankshaft, 132 Crank position sensor, 150 Engine, 152 Intake system, 154 Exhaust system, 160 Accelerator pedal opening sensor, 180 Air conditioner, 1000 Arithmetic , 1010 KL calculator, 1030 throttle calculator, 1040 smoothing processor, 2000 ignition timing calculator, 3000 target efficiency controller

Claims (5)

A control device for an internal combustion engine,
An idling control unit for controlling an output torque during idling of the internal combustion engine;
The idling controller is
Using the maximum efficiency torque based on the current engine speed and the current charging efficiency and the target torque of the output torque at the time of idling, the ignition timing which is a torque down rate by retarding the ignition timing is calculated. , an ignition efficiency control unit that the current ignition efficiency of the internal combustion engine to the control the current ignition efficiency to be equal to the target ignition efficiency,
A maximum efficiency torque is calculated based on the current charging efficiency and the current engine speed, and a target ignition efficiency is calculated based on the maximum efficiency torque and the ignition timing calculated by the ignition efficiency control unit. A target efficiency control unit,
The target efficiency control unit includes: a first process for increasing the target ignition efficiency until the current ignition efficiency reaches a maximum value; and the target efficiency after the current ignition efficiency reaches the maximum value. A control apparatus for an internal combustion engine that alternately executes a second process for changing the maximum value to a value that is lower by a predetermined amount.   The control apparatus for an internal combustion engine according to claim 1, wherein the target efficiency control unit changes the maximum value according to a load of the internal combustion engine.   The control apparatus for an internal combustion engine according to claim 1, wherein the target efficiency control unit changes an increase rate of the target ignition efficiency with respect to time according to a load of the internal combustion engine.   The control apparatus for an internal combustion engine according to claim 1, wherein the target efficiency control unit decreases the ignition efficiency by increasing a charging efficiency of the internal combustion engine. The ignition efficiency control unit
Smoothing the time fluctuation of the target value of the output torque and outputting the target torque;
The control device for an internal combustion engine according to claim 4, further comprising a charging efficiency calculation unit that calculates the charging efficiency based on the target torque from the smoothing processing unit and the target ignition efficiency.

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