阅读说明：本技术 发动机控制器、发动机控制方法和存储介质 (Engine controller, engine control method, and storage medium ) 是由 山田贵文 栗田俊介 于 2020-08-07 设计创作，主要内容包括：提供了发动机控制器、发动机控制方法和存储介质。第二计算处理在不使用空气流量计的输出的情况下计算进气量。第二确定处理在不使用空气流量计的输出的情况下确定进气通路中的进气脉动是否大。当通过第一确定处理和第二确定处理中的至少一个确定处理确定出进气脉动大时,计算方法切换处理选择通过第二计算处理获得的进气量的计算值作为用于确定致动器的操作量的进气量的计算值(图2)。(An engine controller, an engine control method, and a storage medium are provided. The second calculation process calculates the intake air amount without using the output of the air flow meter. The second determination process determines whether the intake pulsation in the intake passage is large without using the output of the air flow meter. When it is determined by at least one of the first determination process and the second determination process that the intake air pulsation is large, the calculation method switching process selects a calculated value of the intake air amount obtained by the second calculation process as a calculated value of the intake air amount for determining the operation amount of the actuator (fig. 2).)

1. An engine controller that controls an operation state of an engine by operation of an actuator provided to the engine, the engine controller being configured to execute:

a first calculation process of calculating an intake air amount introduced into a cylinder of the engine, the first calculation process calculating the intake air amount based on an output of an air flow meter that detects an intake air flow rate in an intake passage of the engine;

a second calculation process of calculating the intake air amount based on at least one of a detected value of an intake pipe pressure and a throttle opening degree without using an output of the air flow meter;

a first determination process that determines whether intake pulsation in the intake passage is large based on an output of the airflow meter;

a second determination process of determining whether intake pulsation in the intake passage is large based on at least one of the detected value of the intake pipe pressure and the throttle opening degree without using the output of the air flow meter; and

a calculation method switching process in which

When it is not determined by both the first determination process and the second determination process that the intake pulsation is large, the calculation method switching process selects the calculated value of the intake air amount obtained by the first calculation process as the calculated value of the intake air amount for determining the operation amount of the actuator, and

when it is determined by at least one of the first determination process and the second determination process that the intake pulsation is large, the calculation method switching process selects the calculated value of the intake air amount obtained by the second calculation process as the calculated value of the intake air amount used to determine the operation amount of the actuator.

2. An engine controller according to claim 1, wherein the second determination process determines that intake pulsation is large on the condition that the throttle opening degree is greater than or equal to a large opening degree determination value that is set based on an engine speed.

3. An engine controller according to claim 1, wherein the second determination process determines that intake pulsation is large on the condition that the intake pipe pressure is greater than or equal to a large pulsation region determination value set based on an engine speed.

4. An engine controller according to claim 1, wherein the second determination process determines that intake pulsation is large based on the fact that fluctuation of the detected value of the intake pipe pressure is large.

5. An engine controller according to any one of claims 1 to 4, configured to execute abnormality determination processing on a condition that the second determination processing has not determined that intake pulsation is large, wherein the abnormality determination processing determines whether there is an abnormality in the air flow meter by using an output of the air flow meter.

6. The engine controller according to claim 5, wherein the abnormality determination process determines that there is an abnormality in the airflow meter based on the fact that a difference between the calculated value of the intake air amount calculated by the first calculation process and the calculated value of the intake air amount calculated by the second calculation process is large.

7. An engine control method that controls an operating state of an engine through operation of an actuator provided to the engine, the engine control method comprising:

calculating an amount of intake air introduced into a cylinder of the engine based on an output of an air flow meter that detects an intake air flow rate in an intake passage of the engine;

calculating the intake air amount based on at least one of a detected value of an intake pipe pressure and a throttle opening degree without using an output of the air flow meter;

determining whether intake pulsation in the intake passage is large based on an output of the air flow meter;

determining whether intake pulsation in the intake passage is large based on at least one of the detected value of the intake pipe pressure and the throttle opening degree without using the output of the air flow meter; and

selecting a calculated value of an intake air amount for determining an operation amount of the actuator, wherein

When it is not determined that the intake air pulsation is large in both of the case where the determination is based on the output of the airflow meter and the case where the output of the airflow meter is not used, a calculated value of an intake air amount based on the output of the airflow meter is selected as a calculated value of an intake air amount used to determine the operation amount of the actuator, and

when it is determined that the intake air pulsation is large in at least one of the case where the determination is based on the output of the air flow meter and the case where the output of the air flow meter is not used, a calculated value of the intake air amount that has been calculated without using the output of the air flow meter is selected as a calculated value of the intake air amount used for determining the operation amount of the actuator.

8. A non-transitory computer-readable storage medium storing a program that causes a processor to execute an engine control process that controls an operating state of an engine through operation of an actuator provided to the engine, the engine control process comprising:

calculating an amount of intake air introduced into a cylinder of the engine based on an output of an air flow meter that detects an intake air flow rate in an intake passage of the engine;

calculating the intake air amount based on at least one of a detected value of an intake pipe pressure and a throttle opening degree without using an output of the air flow meter;

determining whether intake pulsation in the intake passage is large based on an output of the air flow meter;

determining whether intake pulsation in the intake passage is large based on at least one of the detected value of the intake pipe pressure and the throttle opening degree without using the output of the air flow meter; and

selecting a calculated value of an intake air amount for determining an operation amount of the actuator, wherein

When it is not determined that the intake air pulsation is large in both of the case where the determination is based on the output of the airflow meter and the case where the output of the airflow meter is not used, a calculated value of an intake air amount based on the output of the airflow meter is selected as a calculated value of an intake air amount used to determine the operation amount of the actuator, and

when it is determined that the intake air pulsation is large in at least one of the case where the determination is based on the output of the air flow meter and the case where the output of the air flow meter is not used, a calculated value of the intake air amount that has been calculated without using the output of the air flow meter is selected as a calculated value of the intake air amount used for determining the operation amount of the actuator.

Technical Field

The present disclosure relates to an engine controller that controls an engine by calculating an intake air amount introduced into a cylinder and operating an actuator such as an injector based on the calculated value of the intake air amount.

Background

The control of the operating state of the engine is performed by operating actuators such as an injector and a throttle valve. For example, control of the air-fuel ratio of the air-fuel mixture burned in the cylinder is performed by determining the fuel injection amount required to bring the air-fuel ratio to the target value based on the amount of intake air introduced into the cylinder and operating the injector to inject the fuel of the determined fuel injection amount. In order to improve the control accuracy of the above-described engine control, which is performed by determining the operation amount of the actuator based on the intake air amount, it is necessary to accurately acquire the intake air amount.

Known methods of calculating the intake air amount include three methods: a mass flow method, a velocity density method, and a throttle velocity method. In the mass flow method, the intake air amount is calculated from the intake air flow rate detected by an air flow meter disposed in a section of the intake passage upstream of the throttle valve. In the speed density method, the intake air amount is calculated by detecting the intake pipe pressure with an intake pipe pressure sensor disposed in a section of the intake passage downstream of the throttle valve and using the intake air flow rate estimated based on the intake pipe pressure and the engine speed. In the throttle speed method, the intake air amount is calculated from the intake air flow rate estimated based on the throttle opening and the engine speed.

Generally, among the three calculation methods, the mass flow method most accurately calculates the intake air amount during steady operation of the engine. Since each cylinder of the engine intermittently takes in intake air in accordance with the opening and closing of the intake valve, the flow of intake air in the intake passage is accompanied by pulsation. This intake pulsation affects the detection value of the air flow meter. Therefore, in some cases, in the engine operating region where the intake pulsation is large, the speed density method and the throttle speed method calculate the intake air amount more accurately than the mass flow method.

In this regard, japanese laid-open patent publication No. 1-265122 discloses an engine controller that calculates an intake air amount while switching a calculation method according to the magnitude of intake air pulsation. The engine controller of this document determines whether the intake pulsation is large based on the output of the air flow meter. When it is determined that the intake pulsation is not large, the engine controller calculates the intake air amount by a mass flow method. When it is determined that the intake pulsation is large, the engine controller calculates the intake air amount by a speed density method or a throttle speed method.

When the responsiveness of the air flow meter is reduced due to, for example, collected deposits, the intake pulsation is less likely to affect the output of the air flow meter. In this case, it is impossible to accurately determine whether the intake pulsation is large. As a result, the mass flow method may continue to be used to calculate the intake air amount even when the intake pulsation is large. This may reduce the control accuracy of the engine control performed based on the calculated value of the intake air amount.

Disclosure of Invention

This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

Examples of the present disclosure will now be described.

Aspect 1 an aspect of the present disclosure provides an engine controller that controls an operation state of an engine through an operation of an actuator provided to the engine. The engine controller is configured to execute the following processing. A first calculation process of calculating an intake air amount introduced into a cylinder of the engine, and calculating the intake air amount based on an output of an air flow meter that detects an intake air flow rate in an intake passage of the engine. A second calculation process of calculating the intake air amount based on at least one of the detected value of the intake pipe pressure and the throttle opening degree without using the output of the air flow meter. The first determination process determines whether intake pulsation in the intake passage is large based on the output of the air flow meter. The second determination process determines whether intake pulsation in the intake passage is large based on at least one of the detected value of the intake pipe pressure and the throttle opening degree without using the output of the air flow meter. When it is not determined by both the first determination process and the second determination process that the intake air pulsation is large, the calculation method switching process selects the calculated value of the intake air amount obtained by the first calculation process as the calculated value of the intake air amount used to determine the operation amount of the actuator. When it is determined by at least one of the first determination process and the second determination process that the intake pulsation is large, the calculation method switching process selects the calculated value of the intake air amount obtained by the second calculation process as the calculated value of the intake air amount used to determine the operation amount of the actuator.

The first calculation process performs calculation of the intake air amount by a mass flow method based on a detected value of the intake air flow rate of the air flow meter. The second calculation process performs at least one of intake air amount calculation by a speed density method based on the detected value of the intake pipe pressure and intake air amount calculation by a throttle speed method based on the throttle opening degree. When the intake pulsation is large, the detection accuracy of the intake air flow rate acquired by the air flow meter is lowered. Therefore, the accuracy of calculation of the intake air amount of the mass flow method is reduced. The above-described engine controller executes two processes of determining whether intake pulsation is large: a first determination process that performs determination based on an output of the air flow meter; and a second determination process that performs determination based on at least one of the detected value of the intake pipe pressure and the throttle opening degree without using the output of the air flow meter. In either of the first determination process and the second determination process, if it is not determined that the intake pulsation is large, the calculated value of the intake air amount of the first determination process is used as the calculated value of the intake air amount for determining the operation amount of the actuator. In at least one of the first determination process and the second determination process, if it is determined that the intake pulsation is large, the calculated value of the intake air amount of the second determination process is used as the calculated value of the intake air amount for determining the operation amount of the actuator.

The magnitude of the intake air pulsations can be directly derived from the output of the air flow meter. Therefore, it is possible to determine whether the intake pulsation is large by the first determination process as long as it is ensured that the output of the air flow meter is a value that accurately reflects the actual intake air flow rate.

When the throttle opening is larger than a certain degree, the intake pulsation increases. When the throttle opening is increased, the intake pipe pressure is increased. Therefore, even the second determination process based on at least one of the detected value of the intake pipe pressure and the throttle opening degree determines whether the intake pulsation is large with a certain degree of accuracy.

The collected deposits may temporarily reduce the responsiveness of the air flow meter when the engine is running. When the responsiveness is lowered, the intake pulsation is less likely to affect the output of the air flow meter. Therefore, even if the intake pulsation increases, the first determination process may not be able to determine that the intake pulsation has increased. Even in this case, since the determination is performed in a case where the output of the air flow meter is not used, the second determination process determines that the intake pulsation is large. Therefore, the above-described engine controller uses the mass flow rate method even when the responsiveness of the air flow meter temporarily decreases if the intake pulsation is small, and uses the speed density method or the throttle speed method if the intake pulsation is large. That is, the engine controller described above can switch the calculation method for determining the operation amount of the actuator according to the magnitude of the intake pulsation. Therefore, when the responsiveness of the air flow meter temporarily decreases, the above-described engine controller appropriately switches the calculation method for determining the operation amount of the actuator in accordance with the increase or decrease of the intake pulsation.

In the engine controller according to aspect 1, the second determination process may determine that the intake pulsation is large on a condition that the throttle opening degree is greater than or equal to a large opening degree determination value set based on the engine speed.

In the engine controller according to aspect 1, the second determination process may determine that the intake pulsation is large on a condition that the intake pipe pressure is greater than or equal to a large pulsation region determination value set based on the engine speed.

Aspect 4. intake pipe pressure fluctuates when intake pulsation occurs. Therefore, in the engine controller according to aspect 1, the second determination process can determine that the intake pulsation is large based on the fact that the fluctuation of the detected value of the intake pipe pressure is large.

In some cases, the output of the air flow meter is used to determine whether an anomaly exists in the air flow meter. In the case where the increase in the intake air pulsation has lowered the detection accuracy of the air flow meter, the determination as to whether there is an abnormality in the air flow meter cannot be correctly performed by using the output of the air flow meter. Therefore, when the intake pulsation is large, the determination as to whether there is an abnormality is preferably not performed by using the output of the air flow meter.

As described above, the determination as to whether the intake pulsation is large can be performed by the first determination process based on the output of the air flow meter or by the second determination process based on the detected value of the intake pipe pressure or the throttle opening degree. However, in the case where there is a possibility of abnormality in the air flow meter, the determination result of the first determination process based on the air flow meter is not reliable.

Aspect 5 therefore, the engine controller according to aspect 1 is preferably configured to execute an abnormality determination process (S120: NO) on a condition that the second determination process does not determine that the intake pulsation is large, wherein the abnormality determination process determines whether there is an abnormality in the air flow meter by using the output of the air flow meter.

When there is an abnormality in the air flow meter, the calculation accuracy of the intake air amount of the first calculation process based on the output of the air flow meter decreases. In contrast, the calculation accuracy of the intake air amount of the second calculation process that does not use the output of the air flow meter is not lowered. This increases the deviation between the calculated values of the intake air amount of the calculation processing.

Aspect 6 therefore, in the engine controller according to aspect 5, the abnormality determination process is able to determine that there is an abnormality in the airflow meter based on the fact that the difference between the calculated value of the intake air amount calculated by the first calculation process and the calculated value of the intake air amount calculated by the second calculation process is large.

Aspect 7 provides an engine control method that executes the various processes described in any one of the above aspects.

Aspect 8 provides a non-transitory computer-readable storage medium storing a program that causes a processing device to execute various processes described in any one of the above aspects.

Other features and aspects will become apparent from the following detailed description, the accompanying drawings, and the claims.

Drawings

Fig. 1 is a schematic diagram showing an engine controller according to a first embodiment.

Fig. 2 is a block diagram showing the flow of processing relating to fuel injection amount control executed by the engine controller according to the first embodiment.

Fig. 3 is a graph showing the manner in which the pulse rate is calculated in the first determination process that is executed when the engine controller of fig. 2 executes fuel injection amount control.

Fig. 4 is a block diagram showing the flow of processing relating to fuel injection amount control executed by the engine controller according to the second embodiment.

Fig. 5 is a block diagram showing the flow of processing relating to fuel injection amount control executed by the engine controller according to the third embodiment.

Fig. 6 is a graph showing a manner in which the fluctuation rate of the intake pipe pressure is calculated in the fluctuation rate calculation process executed by the engine controller of fig. 5 in the fuel injection amount control.

Fig. 7 is a flowchart of an AFM (air flow meter) abnormality diagnosis routine executed by the engine controller according to the fourth embodiment.

Fig. 8 is a graph showing the relationship between the engine speed and the large pulsation region determination value calculated in the AFM abnormality diagnosis routine of fig. 7.

Like reference numerals refer to like elements throughout the drawings and detailed description. The figures may not be to scale and the relative sizes, proportions and depictions of elements in the figures may be exaggerated for clarity, illustration and convenience.

Detailed Description

This description provides a thorough understanding of the described methods, devices, and/or systems. Variations and equivalents of the described methods, apparatus, and/or systems will be apparent to those of ordinary skill in the art. The order of operations, other than those necessarily occurring in a certain order, is illustrative and may be varied as would be apparent to one of ordinary skill in the art. Descriptions of functions and constructions well known to those of ordinary skill in the art may be omitted.

The exemplary embodiments may have different forms and are not limited to the described examples. The described examples, however, are thorough and complete, and will convey the full scope of the disclosure to those of ordinary skill in the art.

First embodiment

An engine controller according to a first embodiment will now be described with reference to fig. 1 to 3. First, the configuration of the engine controller according to the present embodiment will be described with reference to fig. 1. The engine controller according to the embodiment is employed in the vehicle-mounted multi-cylinder engine 10. FIG. 1 illustrates only one cylinder of a plurality of cylinders in an engine 10.

As shown in fig. 1, an engine 10 in which the engine controller of each embodiment is employed includes an air cleaner 12 for filtering out dust and the like in intake air in the most upstream section of an intake passage 11. The intake passage 11 is provided with an air flow meter 13 in a section downstream of the air cleaner 12, and the air flow meter 13 detects the intake air flow rate GA.

In the present embodiment, a hot wire air flow meter is used as the air flow meter 13. The hot wire air flow meter 13 has a bridge circuit including a resistor for measuring the intake air temperature and a hot wire made of a heating resistor. A resistor for measuring the intake air temperature and a heating resistor are located in the intake passage 11. In the air flow meter 13, the electric power supplied to the heating resistor is feedback-controlled so that the temperature difference between the intake air temperature measuring resistor and the heating resistor is maintained at a certain value. The electric power supplied to the heating resistor is converted into a voltage to be output from the air flow meter 13 as a detection signal of the intake air flow rate GA.

The intake passage 11 is provided with a throttle valve 14 in a section downstream of the airflow meter 13. The throttle valve 14 regulates intake air flow. A throttle motor 15 and a throttle sensor 16 are provided in the vicinity of the throttle valve 14. The throttle motor 15 selectively opens and closes the throttle valve 14. The throttle sensor 16 detects the opening degree of the throttle valve 14. The intake passage 11 is provided with an intake pipe pressure sensor 17 in a section downstream of the throttle valve 14. The intake pipe pressure sensor 17 detects the pressure of the intake air flowing in this section. The opening degree of the throttle valve 14 is hereinafter referred to as a throttle valve opening degree TA. The intake air pressure detected by the intake pipe pressure sensor 17 will be referred to as intake pipe pressure PM.

The intake passage 11 is provided with an injector 18 in a section downstream of the intake pipe pressure sensor 17. The injector 18 injects fuel into intake air. The intake passage 11 is connected to a combustion chamber 20 via an intake valve 19. The combustion chamber 20 is provided with an ignition device 21, and the ignition device 21 ignites the air-fuel mixture by spark discharge.

The combustion chamber 20 is connected to an exhaust passage 23 via an exhaust valve 22. The exhaust passage 23 is provided with an air-fuel ratio sensor 24 and a catalyst device 25. The air-fuel ratio sensor 24 detects the air-fuel ratio of the air-fuel mixture that has been combusted in the combustion chamber 20. The catalyst device 25 purifies exhaust gas. Of the above-described components of the engine 10, the injector 18, the intake valve 19, the combustion chamber 20, the ignition device 21, and the exhaust valve 22 are provided in each of the respective cylinders.

The engine 10 is controlled by an electronic control unit 26 serving as an engine controller. The electronic control unit 26 has an arithmetic processing circuit 27 that executes various types of calculation processing relating to engine control and a memory 28 that stores programs and data for control. The electronic control unit 26 receives detection signals from the airflow meter 13, the throttle sensor 16, the intake pipe pressure sensor 17, and the air-fuel ratio sensor 24. The electronic control unit 26 also receives detection signals from a crank angle sensor 30, an accelerator pedal sensor 32, a vehicle speed sensor 33, a coolant temperature sensor 34, an intake air temperature sensor 35, and an atmospheric pressure sensor 36. The crank angle sensor 30 detects a crank angle CRNK as a rotation angle of the crankshaft 29. The crankshaft 29 is an output shaft of the engine 10. The accelerator pedal sensor 32 detects an accelerator pedal depression amount ACCP that is a depression amount of the accelerator pedal 31. The vehicle speed sensor 33 detects a vehicle speed V of the vehicle on which the engine 10 is mounted. The coolant temperature sensor 34 detects a coolant temperature THW of the engine 10. The intake air temperature sensor 35 detects an intake air temperature THA that is the temperature of intake air drawn into the intake passage 11. The atmospheric pressure sensor 36 detects atmospheric pressure PA.

Based on detection signals from these sensors, the electronic control unit 26 determines the operation amounts of the throttle motor 15, the injector 18, and the ignition device 21 and operates these components, thereby controlling the operating state of the engine 10. The electronic control unit 26 calculates the engine speed NE based on the detection result of the crank angle CRNK acquired by the crank angle sensor 30.

The electronic control unit 26 controls the amount of fuel injected by the injector 18 of each cylinder. In other words, the electronic control unit 26 performs fuel injection amount control as part of engine control. When the fuel injection amount control is executed, the electronic control unit 26 first calculates the amount of intake air introduced into each cylinder of the engine 10. Subsequently, the electronic control unit 26 divides the calculated value of the intake air amount by the stoichiometric air-fuel ratio to obtain a quotient that is used as the command injection amount. The electronic control unit 26 performs fuel injection amount control by operating the injector 18 of each cylinder to inject the amount of fuel corresponding to the command injection amount.

Fig. 2 shows a flow of processing relating to fuel injection amount control executed by the electronic control unit 26. As shown in fig. 2, the fuel injection amount control in the engine controller of the present embodiment is performed by the first calculation process P1, the second calculation process P2, the first determination process P3, the second determination process P4, the calculation method switching process P5, and the injector operation process P6.

The first calculation process P1 calculates the amount of intake air introduced into the cylinders of the engine 10 based on the engine speed NE and the output of the air flow meter 13, which is the detected value of the intake air flow GA acquired by the air flow meter 13. That is, the first calculation process P1 performs the calculation of the intake air amount by the mass flow method based on the intake air amount GA of the airflow meter 13. In the description that follows, the calculated value of the intake air amount that is obtained by the first calculation process P1 will be referred to as a first intake air amount calculated value MC 1.

The second calculation process P2 performs calculation of the intake air amount based on the throttle opening degree TA and the engine speed NE. That is, the second calculation process P2 performs calculation of the intake air amount by the throttle speed method based on the throttle opening degree TA. In the description that follows, the calculated value of the intake air amount that is obtained by the second calculation process P2 will be referred to as a second intake air amount calculated value MC 2.

In the intake passage 11 of the engine 10, intake air intermittently flows into the combustion chamber 20 in response to the opening and closing of the intake valve 19, which generates pressure fluctuation of the intake air. The pressure fluctuation generated in response to the opening and closing of the intake valve 19 propagates upstream over the entire intake passage 11. The first determination process P3 and the second determination process P4 each perform determination as to whether or not the pressure fluctuation or intake air pulsation of the intake air is large at the position in the intake passage 11 where the airflow meter 13 is arranged. In the following description, the determination as to whether such intake pulsation is large will be referred to as pulsation determination.

The first determination process P3 performs pulsation determination based on the output of the airflow meter 13. Specifically, the first determination process P3 determines that the intake pulsation is large when the value of the pulsation rate RTE obtained from the detected value of the intake air flow rate GA acquired by the air flow meter 13 is greater than or equal to a prescribed large pulsation determination value R0. The pulse rate RTE is calculated from the maximum value GMAX, the minimum value GMIN, and the average value GAVE of the intake air flow GA in the prescribed time period T. The difference obtained by subtracting the maximum value GMAX from the maximum value GMAX is divided by the average value GAVE, and the resulting quotient is obtained as the pulse rate RTE. The period T is set to be longer than the period of the intake pulsation.

The second determination process P4 performs a pulsation determination based on the throttle opening degree TA. Specifically, the second determination process P4 determines that the intake pulsation is large when the value of the throttle opening degree TA is greater than or equal to the large opening degree determination value HI. In the present embodiment, the large opening determination value HI is set based on the engine speed NE. The large opening degree determination value HI corresponding to each value of the engine speed NE is set as an upper limit of the throttle opening degree TA that limits a decrease in the detection accuracy of the airflow meter 13 due to the intake pulsation to an allowable range at that value of the engine speed NE.

The calculation method switching process P5 selects one of the first intake air amount calculated value MC1 and the second intake air amount calculated value MC2 as the calculated value of the intake air amount to be given to the injector operation process P6. Specifically, when both the first determination process P3 and the second determination process P4 determine that the intake air pulsation is not large, the first intake air amount calculation value MC1 calculated by the first calculation process P1 is delivered to the injector operation process P6. Specifically, when at least one of the first determination process P3 and the second determination process P4 determines that the intake air pulsation is large, the second intake air amount calculation value MC2 calculated by the second calculation process P2 is given to the injector operation process P6.

The injector operation process P6 calculates a value of a command injection amount Q, which is a command value of the fuel injection amount of the injector 18, based on the calculated value delivered from the calculation method switching process P5, and operates the injector 18 of each cylinder to inject the fuel amount corresponding to the command injection amount Q. Specifically, the injector operation process P6 first divides the calculated value of the intake air amount delivered from the calculation method switching process P5 by the stoichiometric air-fuel ratio and uses the resultant quotient as the value of the basic injection amount QBSE. Further, the command injection amount Q is set to a value obtained by correcting the basic injection amount QBSE by air-fuel ratio feedback correction, for example, based on the detection result of the air-fuel ratio sensor 24, and the injector 18 operates based on the value of the command injection amount Q.

The operation and advantages of the present embodiment will now be described.

In the intake passage 11 of the engine 10, the intermittent opening of the intake valve 19 generates intake pulsation. When such intake pulsation becomes large, the detection accuracy of the airflow meter 13 may decrease due to the influence of the intake pulsation.

To cope with this, the first calculation process P1 of the present embodiment calculates the intake air amount by the mass flow method based on the output of the airflow meter 13, and the second calculation process P2 calculates the intake air amount by the throttle speed method based on the throttle opening degree TA. When the detection accuracy of the airflow meter 13 decreases, the detection accuracy of the intake air amount of the first calculation process P1 also decreases. Therefore, even when the intake pulsation is large, if the command injection amount Q of the injector 18 is determined in the first arithmetic processing P1 by using the first intake air amount calculation value MC1, the control accuracy of the fuel injection amount is lowered. In the present embodiment, when the intake air pulsation is small, the command injection amount Q is determined by using the first intake air amount calculation value MC1 calculated by the first calculation process P1. When the intake pulsation is large, the command injection amount Q is determined by using the second intake air amount calculation value MC2 calculated by the second calculation process P2. As described above, in the present embodiment, when the intake pulsation is large, the calculation method of the intake air amount for determining the fuel injection amount is switched from the mass flow rate method to the throttle speed method. This limits the decrease in the control accuracy of the fuel injection quantity due to the increase in the intake pulsation.

The present embodiment includes two processes of determining whether intake pulsation is large: a first determination process P3 of performing a pulsation determination by using the output of the air flow meter 13P 3; and a second determination process P4 that performs a pulsation determination using the throttle opening degree TA. When at least one of the first determination process P3 and the second determination process P4 determines that the intake pulsation is large, the calculation method of the intake air amount for determining the fuel injection amount is switched from the mass flow rate method to the throttle speed method, assuming that the intake pulsation is large.

The magnitude of the intake air pulsation in the section of the intake passage 11 where the airflow meter 13 is arranged can be estimated with some accuracy from the throttle opening degree TA and the engine speed NE. The second determination process P4 can also perform the pulsation determination with a certain accuracy. If the air flow meter 13 accurately detects the intake air flow rate, the pulsation determination can be performed more accurately by directly acquiring the intake pulsation from the detection result of the air flow meter 13, that is, by the first determination process P3, than by the second determination process P4.

However, when the engine 10 is operating, deposits in the intake air may accumulate on the heat line of the air flow meter 13, and as a result, the responsiveness of the air flow meter 13 is temporarily reduced. In this case, the influence of the intake pulsation cannot be reflected on the output of the airflow meter 13. Therefore, even if the intake pulsation increases, the first determination process P3 may not be able to determine that the intake pulsation is large. When the responsiveness of the air flow meter 13 is low, the pulsation determination by the second determination process P4 using the throttle opening degree TA can be performed in the same manner as when the responsiveness is not low. Therefore, even if the responsiveness of the airflow meter 13 temporarily decreases, at least the second determination process P4 determines that the intake pulsation is large when the intake pulsation is large. As described above, in the present embodiment, when at least one of the first determination process P3 and the second determination process P4 determines that the intake air pulsation is large, the calculation method of the intake air amount is switched from the mass flow rate method to the throttle speed method. Therefore, even when the responsiveness of the airflow meter 13 temporarily decreases, the engine controller of the present embodiment can appropriately switch the method of calculating the intake air amount in accordance with the intake air pulsation. Therefore, the control accuracy of the fuel injection amount can be maintained based on the calculated value of the intake air amount.

In the present embodiment, the injector 18 corresponds to an actuator installed in the engine 10 operated by an engine controller that controls the operating state of the engine 10. A command injection quantity Q, which is a command value of the fuel injection quantity of the injector 18, corresponds to the operation quantity of the actuator.

Setting of high opening determination value HI

The second determination process P4 of the embodiment performs the pulsation determination by comparing the large opening determination value HI set based on the engine speed NE and the throttle opening amount TA with each other. Depending on the operating environment and structure of the engine, there may be state quantities that highly affect the intake pulsation in addition to the engine speed NE and the throttle opening degree TA. In this case, the large opening degree determination value HI can be set using the state quantity in addition to the engine speed NE in order to improve the accuracy of the pulsation determination of the second determination process P4. For example, in an engine equipped with a variable valve timing mechanism that changes the valve timing of the intake valve 19 or the exhaust valve 22, the setting of the valve timing may highly affect the intake pulsation. For example, when the valve timing of the intake valve 19 is retarded to be later than compression bottom dead center, some of the intake air introduced into the combustion chamber 20 during the intake stroke is pushed back into the intake passage 11 after the start of the compression stroke. This increases the intake pulsation. Also, when the valve overlap is changed by changing the valve timing of the intake valve 19 and the exhaust valve 22, the inflow of intake air into the combustion chamber 20 changes, which may affect the intake pulsation. Therefore, in the engine equipped with the variable valve timing mechanism, it is preferable to add the set amount of valve timing used by the variable valve timing mechanism to the state amount for setting the large opening degree determination value HI.

In an engine equipped with an EGR mechanism that recirculates some exhaust gas to the intake air and an engine equipped with a vapor purge mechanism that releases fuel vapor generated in a fuel tank into the intake air, the flow rate of the intake air that flows through the throttle valve 14 changes depending on the amount of recirculated exhaust gas or fuel vapor introduced into the intake air. The relationship between the throttle opening degree TA and the engine speed NE and the magnitude of the intake pulsation changes due to the influence of the changed flow rate. Therefore, in the engine equipped with the EGR mechanism, the amount of exhaust gas recirculated to the intake air is preferably added to the state quantity for setting the large opening determination value HI. In the engine equipped with the vapor purge mechanism, the amount of fuel vapor released into the intake air is preferably added to the state quantity for setting the large opening determination value HI.

The flow rate of intake air passing through throttle valve 14 varies depending on environmental factors such as intake air temperature THA, atmospheric pressure PA, coolant temperature THW, and such variations may affect intake air pulsation. Therefore, when the influence of such environmental factors on the intake air pulsation is large, the intake air temperature THA, the atmospheric pressure PA, and the coolant temperature THW are preferably added to the state quantities for setting the large opening determination value HI.

Setting of hysteresis

In the vehicle-mounted engine, the throttle opening degree TA may be frequently changed depending on the running condition of the vehicle on which the engine is mounted. Therefore, when the throttle opening degree TA repeatedly rises above or falls below the large opening degree determination value HI in a short period of time, the calculation method of the intake air amount is often switched between the mass flow rate method and the throttle speed method, resulting in unstable fuel injection amount control. To cope with this, it is preferable to set a hysteresis in the pulsation determination by the second determination process P4. That is, the second determination process P4 performs the pulsation determination in the following manner. First, as the large opening degree determination value HI, the opening determination value HI1 and the closing determination value HI2 are set. If the intake air pulsation in the previous pulsation determination is not determined to be large, the intake air pulsation is determined to be large if the throttle opening degree TA is greater than or equal to the opening determination value HI 1. In contrast, if the intake air pulsation in the previous pulsation determination is determined to be large, the intake air pulsation is determined to be large if the throttle opening amount TA is less than the off determination value HI 1. As described above, if hysteresis is provided in the pulsation determination by the second determination process P4, the calculation method of the intake air amount is not changed frequently even if the throttle opening degree TA is changed frequently.

Second embodiment

An engine controller according to a second embodiment will now be described with reference to fig. 4. In the second embodiment and the subsequent embodiments, the same structures as those of the first embodiment are denoted by the same reference numerals, and will not be described in detail. The hardware configuration of the engine controller according to the present embodiment and the subsequent embodiments is the same as that of the first embodiment.

The second determination process P4 of the engine controller according to the first embodiment performs the pulsation determination by using the throttle opening degree TA. The throttle opening degree TA is closely related to the pressure of intake air in the section of the intake passage 11 downstream of the throttle valve 14, i.e., the intake pipe pressure PM. That is, when the throttle opening degree TA decreases, the intake pipe pressure PM decreases. When the throttle opening degree TA is increased, the intake pipe pressure PM is increased. Therefore, in the pulsation determination, the second determination process performs the pulsation determination by using the intake pipe pressure PM instead of the throttle opening degree TA.

Fig. 4 shows a flow of processing of the electronic control unit 26 relating to fuel injection amount control in the engine controller of the present embodiment. The first calculation process P1, the second calculation process P2, the first determination process P3, the calculation method switching process P5, and the injector operation process P6 shown in fig. 4 are the same processes as those of the first determination process P3 shown in fig. 2. In the present embodiment, the second determination process P4 executed by the engine controller of the first embodiment is replaced with a standard conversion process P10 and a second determination process P11.

The normalization conversion process P10 calculates a normalization conversion value PMN of the intake pipe pressure PM of the intake pipe pressure sensor 17. The correspondence relationship between the throttle opening degree TA and the intake pipe pressure PM varies in accordance with the atmospheric pressure PA and the intake manifold temperature, which is the temperature of intake air in the section of the intake passage 11 downstream of the throttle valve 14. The intake manifold temperature can be obtained from the intake air temperature THA or the coolant temperature THW. The criteria conversion process P10 subtracts, from the detected value of the intake pipe pressure PM acquired by the intake pipe pressure sensor 17, a variation caused by a difference between the current values of the intake manifold temperature and the atmospheric pressure PA and a prescribed criterion value, and uses the result as the value of the criteria conversion value PMN.

The second determination process P11 performs pulsation determination by using the standard conversion value PMN of the intake pipe pressure PM calculated by the standard conversion process P10. Specifically, the second determination process P11 determines that the intake pulsation is large when the criterion conversion value PMN is greater than or equal to the large pulsation region determination value PH. The large pulsation region determination value PH is set based on the engine speed NE. When the magnitude of the intake pulsation at this engine speed NE is the upper limit of the allowable range in which the detection accuracy of the air flow meter 13 is ensured, the large pulsation region determination value PH corresponding to each value of the engine speed NE is set to the value of the intake pipe pressure PM.

Similar to the first embodiment, the second embodiment can appropriately switch the method of calculating the intake air amount in accordance with the intake air pulsation even when the responsiveness of the airflow meter 13 temporarily decreases. Therefore, the control accuracy of the fuel injection amount can be maintained based on the calculated value of the intake air amount. In the second embodiment, the standard conversion value PMN of the intake pipe pressure PM is used for the pulsation determination by the second determination process P11. This configuration limits the influence of environmental factors such as the intake manifold temperature and the atmospheric pressure PA on the result of the pulsation determination. Therefore, the accuracy of the pulsation determination is improved as compared with the case where the detection value of the intake pipe pressure PM acquired by the intake pipe pressure sensor 17 is used without being changed in the pulsation determination.

If the required determination accuracy is ensured, the detection value of the intake pipe pressure PM acquired by the intake pipe pressure sensor 17 may be used without being changed in the pulsation determination of the second determination process P11. In the case where the second determination process P11 performs the pulsation determination by using the detected value of the intake pipe pressure PM without changing it, the determination accuracy may be ensured by adding the intake air temperature THA, the atmospheric pressure PA, or the coolant temperature THW to the state quantity for setting the large pulsation region determination value PH. In addition, depending on the configuration of the engine, the set value of the valve timing of the intake valve 19 or the exhaust valve 22 set by the variable valve timing mechanism, the amount of exhaust gas recirculated to the intake air by the EGR mechanism, and the amount of fuel vapor released into the intake air by the vapor purge mechanism may be added to the state quantity for setting the large pulsation region determination value PH. Further, in the pulsation determination by the second determination process P11, the above-described hysteresis defined by the determination values H1, H2 may be used.

Third embodiment

An engine controller according to a third embodiment will now be described with reference to fig. 5 and 6.

Fig. 5 shows a flow of processing of the electronic control unit 26 relating to fuel injection amount control in the engine controller of the present embodiment. The first calculation process P1, the second calculation process P2, the first determination process P3, the calculation method switching process P5, and the injector operation process P6 shown in fig. 5 are the same processes as those of the second embodiment shown in fig. 4. In the present embodiment, the standard conversion process P10 and the second determination process P11 executed by the engine controller of the second embodiment are replaced by a fluctuation rate calculation process P20 and a second determination process P21.

The fluctuation rate calculation process P20 calculates the fluctuation rate RPM of the intake pipe pressure PM. The fluctuation rate RPM is calculated from the maximum value PMAX, the minimum value PMIN, and the average value PAVE of the intake pipe pressure PM in the period T. Specifically, the difference obtained by subtracting the minimum PMIN from the maximum value PMAX of the intake pipe pressure PM is divided by the average value PAVE, and the resultant commercial operation fluctuation rate RPM is obtained. Therefore, the fluctuation rate RPM is a parameter indicating the magnitude of fluctuation of the detected value of the intake pipe pressure PM acquired by the intake pipe pressure sensor 17. The above-described period T is set to be longer than the period of intake air pulsation.

The second determination process P21 performs pulsation determination by using the fluctuation rate RPM calculated by the fluctuation rate calculation process P20. Specifically, the second determination process P21 determines that the intake air pulsation is large when the fluctuation rate RPM is greater than or equal to the large fluctuation determination value RH. The large fluctuation determination value RH is set based on the engine speed NE. When the magnitude of the intake pulsation at this engine speed NE is the upper limit of the allowable range in which the detection accuracy of the air flow meter 13 is ensured, the large fluctuation determination value RH corresponding to each value of the engine speed NE is set to the value of the fluctuation rate RPM.

The present embodiment can appropriately switch the method of calculating the intake air amount according to the intake air pulsation even when the responsiveness of the airflow meter 13 temporarily decreases. Therefore, the control accuracy of the fuel injection amount can be maintained based on the calculated value of the intake air amount.

When the influence of environmental factors such as the intake manifold temperature and the atmospheric pressure PA on the result of the pulsation determination is large, the fluctuation rate RPM is preferably calculated by using the standard conversion value PMN of the intake pipe pressure PM in place of the intake pipe pressure PM. The intake air temperature THA, the atmospheric pressure PA, and the coolant temperature THW may be added to the state quantities for setting the large fluctuation determination value RH. In addition, depending on the configuration of the engine, the set value of the valve timing of the intake valve 19 or the exhaust valve 22 set by the variable valve timing mechanism, the amount of exhaust gas recirculated to the intake air by the EGR mechanism, and the amount of fuel vapor released into the intake air by the vapor purge mechanism may be added to the state quantity for setting the large fluctuation determination value RH. Further, in the pulsation determination by the second determination process P21, the above-described hysteresis defined by the determination values H1, H2 may be used.

Fourth embodiment

An engine controller according to a fourth embodiment will now be described with reference to fig. 7 and 8. The engine controller of the present embodiment executes the fuel injection amount control in the same manner as in the first embodiment. The engine controller of the present embodiment performs abnormality diagnosis of the airflow meter 13 during operation of the engine 10.

Fig. 7 is a flowchart of an AFM abnormality diagnosis routine relating to abnormality diagnosis of the air flow meter 13. The electronic control unit 26 repeatedly executes the processing of this routine every prescribed control cycle during operation of the engine 10.

When this routine is started, first, the value of the large pulsation region determination value PH0 is calculated based on the engine speed NE in step S100. Subsequently, in step S100, it is determined whether the detected value of the intake pipe pressure PM acquired by the intake pipe pressure sensor 17 is greater than or equal to the large pulsation region determination value PH 0. If the detected value of the intake pipe pressure PM is greater than or equal to the large pulsation region determination value PH0 (S110: yes), the processing of the present routine ends. If the detected value of the intake pipe pressure PM is smaller than the large pulsation region determination value PH0 (S110: no), the process proceeds to step S120.

When the process moves to step S120, it is determined whether the value of the throttle opening degree TA is greater than or equal to the large opening degree determination value HI. That is, in step S120, the same determination as the pulsation determination of the second determination process P4 shown in fig. 2 is performed. If the value of the throttle opening degree TA is greater than or equal to the large opening degree determination value HI (S120: YES), the processing of the present routine is ended. If the throttle opening degree TA is smaller than the large opening degree determination value HI (S120: NO), the process proceeds to step S130.

When the process moves to step S130, it is determined whether the difference between the first intake air amount calculated value MC1 that has been calculated by the first calculation process P1 and the second intake air amount calculated value MC2 that has been calculated by the second calculation process P2 is greater than or equal to the prescribed abnormality determination value MA. If the difference is greater than or equal to the abnormality determination value MA (S130: YES), it is determined in step S140 that there is an abnormality in the air flow meter 13. Thereafter, the processing of the current routine ends. If the difference is smaller than the abnormality determination value MA (S130: no), it is determined in step S150 that there is no abnormality in the air flow meter 13. Thereafter, the processing of the current routine ends.

Fig. 8 shows the relationship between the large pulsation region determination value PH0 and the engine speed NE. In fig. 8, a long and two short dashes line represents an intended switching line. As shown in fig. 8, at any value of the engine speed NE, the large pulsation region determination value PH0 is set lower than the expected switching line.

The expected switching line is obtained from the measurement results shown below. Under standard environmental conditions in which the intake air temperature THA, the atmospheric pressure PA, and the coolant temperature THW each have standard values, the throttle opening degree TA is gradually increased from a value at which the pulsation rate RTE obtained from the detected value of the intake air flow rate GA is smaller than the large pulsation determination value R0 while maintaining the engine speed NE at a constant value. The intake pipe pressure PM when the pulse rate RTE has reached the large pulsation determination value R0 is measured. That is, the intake pipe pressure PM at the time when it is determined by the first determination process P3 that the intake pulsation is large is measured. In the following description, this measurement value of the intake pipe pressure PM will be referred to as a switching pressure PMC. The switching pressure PMC is measured at different values of the engine speed NE to obtain the switching pressure PMC at each value of the engine speed NE of the engine as a measurement subject. The same measurements are performed on multiple engines. The average value of the switching pressure PMC at each value of the engine speed NE of the respective engines is plotted to obtain an expected switching line. That is, the expected switching line represents the operating line of a standard single engine at which the method of calculating the intake air amount under standard environmental conditions is switched between the mass flow method and the throttle speed method.

The operation and advantages of the engine controller according to the present embodiment configured in the above-described manner will now be described.

The engine controller of the present embodiment determines whether there is an abnormality in the airflow meter 13 in step S130 of the AFM abnormality determination routine. That is, when the difference between the first intake air amount calculated value MC1, which has been calculated by the first calculation process P1, and the second intake air amount calculated value MC2, which has been calculated by the second calculation process P2, is greater than or equal to the prescribed abnormality determination value MA, the engine controller determines that there is an abnormality in the air flow meter 13. The first intake air amount calculated value MC1, which has been calculated by the first calculation process P1 based on the output of the airflow meter 13, is an incorrect value if there is an abnormality in the airflow meter 13. On the other hand, even if there is an abnormality in the air flow meter 13, the calculation result of the second intake air amount calculation value MC2 in the second calculation process P2 by the throttle speed method is not affected. Therefore, when there is an abnormality in the air flow meter 13, the difference between the first intake air amount calculated value MC1 and the second intake air amount calculated value MC2 increases. Therefore, it is possible to determine that there is an abnormality in the air flow meter 13 based on the fact that the difference between the intake air amount calculated values is large.

However, when the intake pulsation is large, the first intake air amount calculation value MC1 calculated based on the output of the airflow meter 13 may not be accurate. Therefore, when the intake pulsation is large, the abnormality diagnosis of the air flow meter 13 cannot be accurately performed by using the output of the air flow meter 13.

As in the first determination process P3 of fig. 2, the determination as to whether the intake pulsation is large can be performed by using the output of the airflow meter 13. However, if there is an abnormality in the air flow meter 13, the result of the pulsation determination by using the output of the air flow meter 13 is not reliable. Therefore, the determination by using the air flow meter 13 is not suitable as the pulsation determination for the abnormality diagnosis of the air flow meter 13.

In this regard, in the present embodiment, if it is determined in step S110 that the intake pipe pressure PM is greater than or equal to the large pulsation region determination value PH0, the abnormality determination of the airflow meter 13 in step S130 is not performed. As shown in fig. 8, the region where it is determined in step S110 that the intake pipe pressure PM is greater than or equal to the large pulsation region determination value PH0 is included in the region where the intake pulsation is expected to be determined to be large by the first determination process P3 (i.e., the region on the larger pressure side of the expected switching line). Therefore, in many cases, the abnormality determination of the air flow meter 13 by using the output of the air flow meter 13 is prohibited because the intake pipe pressure PM reaches or exceeds the large pulsation region determination value PH0 before the intake pulsation increases to a level that requires switching the calculation method of the intake air amount from the mass flow method to the throttle speed method.

Further, in the present embodiment, if the throttle opening degree TA is determined to be greater than or equal to the large opening degree determination value HI in step S120, the abnormality determination of the airflow meter 13 in step S130 is not performed. That is, when it is determined by the second determination process P4 that the intake air pulsation is large, the abnormality determination of the airflow meter 13 by using the airflow meter 13 is prohibited.

As described above, in the present embodiment, the pulsation determination that determines whether the abnormality determination of the air flow meter 13 by using the air flow meter 13 should be performed is performed without using the air flow meter 13. Therefore, the abnormality determination is not performed when the intake pulsation is large, regardless of whether there is an abnormality in the airflow meter 13.

In the present embodiment, the process of step S130 of the AFM abnormality diagnosis routine corresponds to an abnormality determination process of determining whether there is an abnormality in the air flow meter by using the output of the air flow meter.

The above-described embodiment may be modified as follows. The above-described embodiments and the following modifications can be combined as long as the combined modifications are technically kept consistent with each other.

In the fourth embodiment, the abnormality determination process is executed based on the difference between the first intake air amount calculated value MC1 and the second intake air amount calculated value MC 2. Alternatively to this configuration, whether there is an abnormality in the air flow meter 13 can be determined by monitoring the output of the air flow meter 13. That is, the abnormality determination process may be performed in a different manner from the above-described manner based on the output of the airflow meter 13. For example, the estimated value of the intake air flow rate GA may be obtained based on the throttle opening degree TA or the intake pipe pressure PM and the engine speed NE, and the abnormality determination process may be executed by determining that there is an abnormality in the airflow meter 13 when the difference between the estimated value and the detected value of the airflow meter 13 is large.

The process of step S110 in the AFM abnormality determination routine in the fourth embodiment may be omitted. Also in this case, the abnormality determination processing is preferably executed after the processing of step S120 is executed. In other words, the abnormality determining process is preferably executed on the condition that the throttle opening degree TA is smaller than the large opening degree determination value HI, that is, on the condition that the second determining process P4 has not determined that the intake pulsation is large. If the processing of step S120 of the AFM abnormality diagnosis routine is changed to that shown below, the switching of the calculation method for determining the intake air amount of the command injection amount Q can be used for the abnormality diagnosis of the air flow meter 13 in the engine controller performed according to the second and third embodiments. That is, the process of step S120 may be replaced with a step of making an affirmative determination (S120: YES) when the second determination process P11 or the second determination process P21 determines that the intake air pulsation is large, and making a negative determination when the second determination process P11 or the second determination process P21 does not determine that the intake air pulsation is large.

The second calculation process P2 of each of the above-described embodiments calculates the intake air amount by the throttle speed method. However, the intake air amount may be calculated by a speed density method based on the detected value of the intake pipe pressure PM. Even in this case, the second calculation process P2 calculates the intake air amount without using the output of the airflow meter 13. Therefore, if the calculated value of the intake air amount of the second calculation process P2 is used as the calculated value of the intake air amount for determining the command injection quantity Q of the injector 18 when the intake pulsation is large, the decrease in the control accuracy of the fuel injection quantity due to the increase in the intake pulsation is restricted.

In each of the above-described embodiments, the calculation method switching process P5 selects one of the first intake air amount calculated value MC1 and the second intake air amount calculated value MC2 as a calculated value of the intake air amount, and the selected calculated value is used to determine the command injection amount Q of the injector 18. The calculated value of the intake air amount selected by the calculation method switching process P5 may be used to determine the operation amount of an actuator provided in the engine 10 other than the injector 18. The operation amount of the actuator may be a command value of a throttle opening degree TA given to the throttle motor 15 or a command value of an ignition timing given to the ignition device 21. Further, the operation amount of the actuator may be a command value of the valve timing to be delivered to the variable valve timing mechanism, a command value of the recirculation amount of the exhaust gas to be delivered to the EGR device, or a command value of the emission amount of the fuel vapor to be delivered to the vapor purge mechanism.

The electronic control unit 26 is not limited to a device that includes the arithmetic processing circuit 27 and the memory 28 and executes various types of software processing. For example, at least a part of the processes performed by software in the above-described embodiments may be performed by a hardware circuit (such as an ASIC) dedicated to performing these processes. That is, the electronic control unit 26 may be modified as long as it has any one of the following configurations (a) to (c). (a) A configuration includes a processor that performs all the above-described processes according to a program and a program storage device such as a ROM (including a non-transitory computer-readable storage medium) that stores the program. (b) A configuration includes a processor and a program storage device that perform a part of the above-described processing according to a program, and a dedicated hardware circuit that performs the remaining processing. (c) A construction comprising dedicated hardware circuitry to perform all of the above-described processing. A plurality of software processing means may be provided each comprising a processor and program storage means together with a plurality of dedicated hardware circuits.

Various changes in form and details may be made to the above examples without departing from the spirit and scope of the claims and their equivalents. These examples are for the purpose of description only and not for the purpose of limitation. The description of features in each example should be considered applicable to similar features or aspects in other examples. Suitable results may be achieved if the sequences are performed in a different order and/or if components in the described systems, architectures, devices, or circuits are combined differently and/or replaced or supplemented by other components or their equivalents. The scope of the present disclosure is defined not by the detailed description but by the claims and their equivalents. All changes that come within the scope of the claims and their equivalents are intended to be embraced therein.