JP2019190341A - Control device of internal combustion engine - Google Patents

Abstract

To provide a control device capable of properly suppressing degradation of accuracy in controlling an air-fuel ratio in an internal combustion engine.SOLUTION: An ECU 50 is applied to an engine 10 including a cylinder internal pressure sensor 40 detecting a cylinder internal pressure of a cylinder 23. The ECU 50 reflects a result of learning of an air-fuel ratio on a fuel injection amount of the engine 10 in controlling an actual air-fuel ratio of the engine 10 to a target air-fuel ratio. Further the ECU 50 determines whether accidental fire occurs in the engine 10 or not on the basis of the cylinder internal pressure detected by the cylinder internal pressure sensor 40, and inhibits the learning of air-fuel ratio when the occurrence of accidental fire is determined.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control device for an internal combustion engine.

  Patent Document 1 discloses a control device that performs air-fuel ratio control for controlling an actual air-fuel ratio of an internal combustion engine to a target air-fuel ratio. Further, the control device calculates an air-fuel ratio correction value based on the deviation between the actual air-fuel ratio and the target air-fuel ratio, and performs air-fuel ratio learning based on the calculated air-fuel ratio correction value. Then, the air-fuel ratio control is suitably performed by reflecting the learning value of the air-fuel ratio as a fuel injection amount.

Japanese Patent No. 2767344

  When the air-fuel ratio learning is performed, misfiring in which the air-fuel mixture in the cylinder does not ignite occurs, so that the actual air-fuel ratio at the time of air-fuel ratio learning shifts to the lean side, and the learning result may become excessively rich. There is a concern that the accuracy of the air-fuel ratio control is lowered by reflecting such a learning result on the fuel injection amount. In addition, there is a concern that an erroneous determination that a fuel system abnormality has occurred due to an excessively rich learning result due to the influence of misfire.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a control device that can suitably suppress a decrease in accuracy of air-fuel ratio control in an internal combustion engine.

  In order to solve the above-described problems, the present invention relates to a control device applied to an internal combustion engine including an in-cylinder pressure detecting unit that detects an in-cylinder pressure of a cylinder. The control device includes: an air-fuel ratio control unit that controls the actual air-fuel ratio of the internal combustion engine to a target air-fuel ratio; a learning unit that performs air-fuel ratio learning when the air-fuel ratio control unit controls the actual air-fuel ratio; A reflecting unit that reflects the learning result of the fuel ratio learning on the fuel injection amount of the internal combustion engine. In addition, the control device includes a misfire determination unit that determines whether or not a misfire has occurred in the internal combustion engine based on the in-cylinder pressure detected by the in-cylinder pressure detection unit, and the misfire determination unit by the misfire determination unit. And a prohibiting unit that prohibits the learning of the air-fuel ratio by the learning unit when it is determined that it has occurred.

  Since the combustion pressure differs between when the internal combustion engine burns and when it misfires, it is possible to determine the misfire of the internal combustion engine based on the in-cylinder pressure. Therefore, in the above configuration, whether or not misfire has occurred in the internal combustion engine is determined based on the in-cylinder pressure detected by the pressure detection unit, and if it is determined that misfire has occurred, the learning unit Fuel ratio learning is prohibited. In this case, by determining misfire based on the in-cylinder pressure, compared with the configuration for determining misfire based on the rotational speed of the internal combustion engine, in a low load region where the difference in rotational speed between combustion and misfire is small. A decrease in the determination accuracy can be suppressed. For this reason, it is possible to suitably suppress a decrease in the accuracy of control of the actual air-fuel ratio due to the influence of misfire.

The block diagram of an engine control system. The figure which shows transition of in-cylinder pressure. The flowchart which shows the procedure which switches the permission and prohibition of air-fuel ratio learning. The figure explaining the determination value used when determining the presence or absence of misfire. The timing chart which switches permission and prohibition of air-fuel ratio control.

(First embodiment)
Hereinafter, an engine control system as an embodiment embodying the present invention will be described with reference to the drawings.

  The engine control system shown in FIG. 1 includes an engine 10 as an internal combustion engine mounted on a vehicle. The engine 10 is an in-cylinder injection type four-cycle gasoline engine and a multi-cylinder gasoline engine. In FIG. 1, only one cylinder 23 is shown, and the other cylinders are not shown.

  An intake port 31 and an exhaust valve 32 that open and close according to the rotation of a camshaft (not shown) are provided at an intake port and an exhaust port of the engine body 20 constituting the engine 10, respectively. The intake air flowing through the intake passage 11 is introduced into the cylinder 23 by the opening operation of the intake valve 31. Further, the exhaust after combustion is discharged into the exhaust passage 35 by the opening operation of the exhaust valve 32. The intake valve 31 and the exhaust valve 32 are respectively provided with variable valve mechanisms 33 and 34 that make the opening / closing timing of the intake valve 31 and the exhaust valve 32 variable. As the variable valve mechanisms 33 and 34, hydraulically driven or electric variable valve mechanisms may be used.

  The engine body 20 is provided with an electromagnetically driven injector 21 for each cylinder 23, and fuel from the injector 21 is directly injected into a combustion chamber defined by the cylinder inner wall and the upper surface (top) of the piston 22. Is done.

  A spark plug 36 is attached to the cylinder head of the engine 10. A high voltage is applied to the spark plug 36 at a desired ignition timing Tig through an ignition coil (not shown). By applying this high voltage, a spark discharge is generated between the opposing electrodes of each spark plug 36, and the fuel in the cylinder 23 is ignited.

  The engine body 20 is provided with a crank angle sensor 42 that outputs the rotational position of the crankshaft 43 as a crank angle signal for each predetermined crank angle. Further, the rotational speed of the crankshaft 43 can be detected as the engine rotational speed NE based on the crank angle signal output from the crank angle sensor 42.

  Each cylinder 23 is provided with an in-cylinder pressure sensor 40 that detects the pressure in the cylinder 23 as an in-cylinder pressure Pf. The in-cylinder pressure sensor 40 corresponds to an in-cylinder pressure detection unit.

  The intake passage 11 is provided with an air flow meter 12 for detecting the amount of intake air taken into the cylinder 23 as the intake air amount. In the intake passage 11, a throttle valve 14 whose opening degree is adjusted by a throttle actuator 13 such as a DC motor is provided downstream of the air flow meter 12. In the intake passage 11, a surge tank 16 and an intake manifold 18 that introduces intake air flowing through the surge tank 16 into each cylinder 23 are provided downstream of the throttle valve 14.

  The exhaust passage 35 is provided with an air-fuel ratio sensor 38 that detects the air-fuel ratio of the exhaust.

  The engine 10 includes an ECU 50 as a control device. The outputs of the various sensors 12, 38, 40, and 42 described above are input to the ECU 50. The ECU 50 includes a microcomputer including a CPU, a ROM, a RAM, and the like. By executing various control programs stored in the ROM, the ECU 50 controls the fuel injection amount of the injector 21 in accordance with the engine operating state and the ignition of the spark plug 36. The timing Tig is controlled.

  The ECU 50 performs air-fuel ratio control for controlling the actual air-fuel ratio detected by the air-fuel ratio sensor 38 to a target air-fuel ratio (for example, theoretical air-fuel ratio). As the air-fuel ratio control, the ECU 50 calculates an air-fuel ratio correction coefficient for correcting the basic fuel injection amount based on the deviation between the actual air-fuel ratio and the target air-fuel ratio. The basic injection amount is, for example, an injection amount calculated based on the engine speed and the engine load. The ECU 50 corrects the basic injection amount using various correction coefficients including an air-fuel ratio correction coefficient, and calculates the corrected value as the final injection amount. Then, the final injection amount is converted into the injection time of the injector 21, and the converted injection time is set as the valve opening time of the injector 21. In the present embodiment, the ECU 50 corresponds to an air-fuel ratio control unit.

  The ECU 50 performs air-fuel ratio learning when performing air-fuel ratio control. In the air-fuel ratio learning, a steady-state deviation of the air-fuel ratio correction coefficient due to individual differences of the injectors 21 or changes over time is calculated and stored as an air-fuel ratio learning value. Specifically, the ECU 50 calculates an air-fuel ratio learning value based on the air-fuel ratio correction coefficient, and stores this air-fuel ratio learning value in a memory. The ECU 50 corrects the basic injection amount with the stored air-fuel ratio learning value during the air-fuel ratio control, thereby reflecting the air-fuel ratio learning value in the fuel injection amount. In the present embodiment, the ECU 50 corresponds to a learning unit and a reflection unit.

  In the air-fuel ratio learning, for example, a plurality of operation regions divided by the engine speed NE and the engine load EL are determined, and the ECU 50 calculates and stores an air-fuel ratio learning value for each operation region. The engine load EL may be determined according to at least one of the intake air amount, the accelerator opening indicating the accelerator depression amount, and the fuel injection amount from the injector 21.

  In the air-fuel ratio learning performed by the ECU 50, a misfire that does not ignite the air-fuel mixture in the cylinder 23 may cause the actual air-fuel ratio at the time of air-fuel ratio learning to shift to the lean side, and the learning result may become excessively rich. . There is a concern that the accuracy of the air-fuel ratio control is lowered by reflecting such a learning result on the fuel injection amount. In addition, there is a concern that an erroneous determination that a fuel system abnormality has occurred due to an excessively rich learning result due to the influence of misfire.

  Therefore, in the present embodiment, the ECU 50 determines whether misfire has occurred in the engine 10 based on the in-cylinder pressure. When the ECU 50 determines that misfire has occurred, the ECU 50 prohibits the execution of air-fuel ratio learning.

  Next, the principle of determining the presence or absence of misfire based on the in-cylinder pressure will be described. FIG. 2 shows the transition of the in-cylinder pressure Pf, where the horizontal axis is the crank angle (deg. CA) and the vertical axis is the in-cylinder pressure Pf (bar). Note that FIG. 2 shows the transition of the in-cylinder pressure Pf with the crank angle at the TDC (top dead center) as the center (= 0 deg. CA), and the intake stroke and the compression stroke are shown by a negative crank angle. The expansion stroke and the exhaust stroke are indicated by a positive crank angle. In FIG. 2, the transition of the in-cylinder pressure Pf when combustion occurs in the cylinder 23 is indicated by a solid line, and the transition of the in-cylinder pressure Pf when partial misfire occurs is indicated by a broken line.

  The in-cylinder pressure Pf increases in the compression stroke ST1, and becomes maximum after a predetermined crank angle from TDC. Thereafter, the in-cylinder pressure Pf decreases in the expansion stroke ST2. Thereafter, when the exhaust valve 32 is opened, the mixed gas in the cylinder 23 is exhausted through the exhaust passage 35.

  When misfire occurs, the air-fuel mixture is not combusted in the cylinder 23, and the in-cylinder pressure Pf becomes smaller than that at the time of combustion. In FIG. 2, in the compression stroke ST1, the increase amount of the in-cylinder pressure Pf at the time of misfire is smaller than the increase amount of the in-cylinder pressure Pf at the time of combustion. Therefore, the ECU 50 determines the presence or absence of misfire based on the in-cylinder pressure Pf, and prohibits air-fuel ratio learning when it is determined that misfire has occurred. Further, by determining misfire based on the in-cylinder pressure Pf, compared with the case where misfire is determined based on the engine rotational speed NE, the difference in rotational speed between the time of combustion and the time of misfire is small. A decrease in determination accuracy can be suppressed.

  The engine 10 has a timing at which the in-cylinder pressure Pf becomes maximum from the compression stroke ST1 to the expansion stroke ST2. In FIG. 2, the in-cylinder pressure Pf becomes maximum values P1 and P2 in the vicinity of the top dead center TDC both during combustion and during misfire. That is, the difference in in-cylinder pressure Pf between combustion and misfire becomes significant during this period. Therefore, in this embodiment, the ECU 50 determines whether or not the engine 10 has misfired based on the maximum in-cylinder pressure from the compression stroke ST1 to the expansion stroke ST2.

  Next, a procedure for switching between permitting and prohibiting air-fuel ratio learning according to the present embodiment will be described with reference to FIG. The processing shown in FIG. 3 is repeatedly performed by the ECU 50 at a predetermined cycle. In each step of FIG. 3, steps S12 to S18 correspond to a misfire determination unit, and step S19 corresponds to a prohibition unit.

  In step S11, it is determined whether or not a learning execution condition for air-fuel ratio learning is satisfied. As the learning effective condition, for example, the condition is that the temperature of the coolant flowing through the engine 10 is equal to or higher than a predetermined value.

  If it is determined that the learning execution condition is satisfied, the process proceeds to step S12, and the maximum in-cylinder pressure Pm is acquired. In the present embodiment, the maximum in-cylinder pressure Pm of the in-cylinder pressure Pf detected by the in-cylinder pressure sensor 40 is acquired in the period from the compression stroke to the expansion stroke. For example, it may be determined based on the crank angle signal CA from the crank angle sensor 42 whether or not the stroke of the engine 10 is a period from the compression stroke to the expansion stroke.

  In step S13, it is determined whether or not a learning permission flag F1 indicating that air-fuel ratio learning can be performed is at a high level. In the present embodiment, the learning permission flag F1 is set to a high level when air-fuel ratio learning can be performed, and the learning permission flag F1 is set to a low level when air-fuel ratio learning is prohibited. Therefore, whether or not air-fuel ratio learning can be performed can be determined based on the value of the learning permission flag F1. Here, assuming that the learning permission flag F1 is at the high level, the process proceeds to step S14.

  In step S14, a misfire determination value THA for determining whether or not the engine 10 has misfired is set. The in-cylinder pressure Pf varies depending on the engine speed NE, the engine load EL, or the ignition timing Tig. Accordingly, in step S14, the misfire determination value THA is set based on the engine speed NE, the engine load EL, and the ignition timing Tig.

  The influence of the engine speed NE and the engine load EL on the change of the in-cylinder pressure Pf is larger than the influence of the ignition timing Tig on the change of the in-cylinder pressure Pf. Therefore, in the present embodiment, the base determination value THa indicating the base value of the misfire determination value THA is set based on the engine rotation speed NE and the engine load EL. Further, a determination correction value k for correcting the base determination value THa is set according to the ignition timing Tig. Then, a value obtained by adding the determination correction value k to the base determination value THa is calculated as the misfire determination value THA.

  FIG. 4A is a diagram illustrating the relationship between the engine speed NE and the engine load EL, and the base determination value THa. FIG. 4B illustrates the relationship between the ignition timing Tig and the determination correction value k.

  The in-cylinder pressure Pf changes in accordance with the engine speed NE. Therefore, as shown in FIG. 4A, the base determination value THa is set according to the engine speed NE. Further, the in-cylinder pressure Pf increases as the engine load EL increases. Therefore, the base determination value THa is set to a larger value as the engine load EL is larger.

  The combustion speed in the cylinder 23 becomes slower and the in-cylinder pressure Pf decreases as the ignition timing Tig becomes more retarded with respect to the reference ignition timing. Further, as the ignition timing Tig is advanced with respect to the reference ignition timing with respect to the crank angle, the combustion speed in the cylinder 23 increases and the in-cylinder pressure Pf increases. Therefore, as shown in FIG. 4B, the determination correction value k is set to a larger value as the ignition timing Tig becomes more advanced with respect to the reference ignition timing.

  For example, a map that defines the relationship between the combination of the engine speed NE and the engine load EL and the combination of the base determination value THa is held. Then, the base determination value THa corresponding to the combination of the engine speed NE and the engine load EL may be referred to from this map. Further, a map that defines the relationship between the ignition timing Tig and the determination correction value k is held. Then, a determination correction value k corresponding to the ignition timing Tig may be referred to from this map.

  Returning to FIG. 3, in step S15, it is determined whether or not the maximum in-cylinder pressure Pm acquired in step S12 is equal to or less than the misfire determination value THA set in step S14. If it is determined that the maximum in-cylinder pressure Pm is greater than the misfire determination value THA, it is determined that no misfire has occurred, and the process of FIG. On the other hand, if it is determined that the maximum in-cylinder pressure Pm is equal to or less than the misfire determination value THA, the process proceeds to step S16.

  In the present embodiment, in order to improve reliability when it is determined that misfire has occurred, air-fuel ratio learning is performed on the condition that the state where the maximum in-cylinder pressure Pm is equal to or less than the misfire determination value THA continues for a predetermined time. Is prohibited. Specifically, first, in step S16, the first counter Co1 that counts the duration during which the maximum in-cylinder pressure Pm is equal to or less than the misfire determination value THA is increased. In step S17, it is determined whether or not the first counter Co1 is larger than the first continuation determination value THB. Here, assuming that the first counter Co1 is less than or equal to the first continuation determination value THB, the processing in FIG. 3 is temporarily terminated.

  Thereafter, the state in which the maximum in-cylinder pressure Pm is equal to or less than the misfire determination value THA continues, so that the first counter Co1 is incremented every calculation cycle of the process of FIG. On the other hand, if it is determined in step S15 that the maximum in-cylinder pressure Pm is greater than the misfire determination value THA, the first counter Co1 is reset. If it is determined in step S17 that the first counter Co1 is greater than the first continuation determination value THB, the process proceeds to step S18.

  When the process proceeds to step S18, it can be determined that misfire has occurred in the engine 10, and therefore, the air-fuel ratio learning is prohibited by changing the learning permission flag F1 from the high level to the low level. In this case, the first counter Co1 is reset.

  When the process of step S18 ends, the process of FIG. 3 is temporarily ended.

  In the next calculation cycle, when the process proceeds to step S13, if it is determined that the learning permission flag F1 is at the low level, the process proceeds to step S21. In step S21, it is determined whether or not the maximum in-cylinder pressure Pm acquired in step S12 is greater than the misfire determination value THA. If it is determined that the maximum in-cylinder pressure Pm is equal to or less than the misfire determination value THA, it can be determined that misfire continues, and the process of FIG. 3 is temporarily terminated. On the other hand, if it is determined that the maximum in-cylinder pressure Pm is greater than the misfire determination value THA, it can be determined that the misfire of the engine 10 has been eliminated, and the process proceeds to step S22.

  In the present embodiment, in order to improve the reliability of the determination that the misfire has been eliminated, the air-fuel ratio learning is performed on the condition that the state where the maximum in-cylinder pressure Pm is larger than the misfire determination value THA continues for a predetermined time. Remove the ban. Therefore, first, in step S22, the second counter Co2 that measures the duration of the state where the maximum in-cylinder pressure Pm is larger than the misfire determination value THA is increased. In step S23, it is determined whether or not the second counter Co2 is larger than the second continuation determination value THC. If it is determined that the second counter Co2 is equal to or smaller than the second continuation determination value THC, the processing in FIG. 3 is once ended.

  When the state where the maximum in-cylinder pressure Pm is greater than the misfire determination value THA continues, if it is determined that the second counter Co2 is greater than the second continuation determination value THC, the process proceeds to step S24. In step S24, the prohibition of air-fuel ratio learning is canceled by changing the learning permission flag F1 from the low level to the high level. In this case, the second counter Co2 is reset. Note that the second counter Co2 is also reset when it is determined in step S21 that the maximum in-cylinder pressure Pm is equal to or less than the misfire determination value THA.

  When the process of step S24 ends, the process of FIG. 3 is temporarily ended.

  Next, the operation of this embodiment will be described with reference to FIG. FIG. 5A shows the transition of the engine speed NE. FIG. 5B shows the transition of the engine load EL. FIG. 5C shows the transition of the maximum in-cylinder pressure Pm acquired from the compression stroke to the expansion stroke. FIG. 5D shows the transition of the first counter Co1. FIG. 5E shows the transition of the second counter Co2. FIG. 5F shows the transition of the learning permission flag F1.

  First, at times t11 to t14, the learning permission flag F1 is at a high level, and air-fuel ratio learning is permitted.

  From time t11 to time t12, the engine load EL increases, and the maximum in-cylinder pressure Pm increases as the engine load EL increases. Then, after time t12, the maximum in-cylinder pressure Pm decreases as the engine load EL decreases.

  At time t13, when the maximum in-cylinder pressure Pm becomes equal to or less than the misfire determination value THA, the first counter Co1 starts to increase. Even after time t13, since the maximum in-cylinder pressure Pm is equal to or lower than the misfire determination value THA, the first counter Co1 continues to increase. At time t14, the first counter Co1 becomes larger than the first continuation determination value THB, and the learning permission flag F1 is changed from the high level to the low level. Therefore, air-fuel ratio learning is prohibited.

  Thereafter, the misfire of the engine 10 is eliminated between the times t14 and t15, so that the maximum in-cylinder pressure Pm is changed from decreasing to increasing at the time t15. At time t16, when the maximum in-cylinder pressure Pm becomes larger than the misfire determination value THA, the second counter Co2 starts to increase. Even after time t16, since the maximum in-cylinder pressure Pm is larger than the misfire determination value THA, the second counter Co2 continues to increase. At time t17, the second counter Co2 becomes larger than the second continuation determination value THC, and the learning permission flag F1 is changed from the low level to the high level. Therefore, the prohibition of air-fuel ratio learning is lifted.

  The embodiment described above has the following effects.

  The ECU 50 performs air-fuel ratio learning when controlling the actual air-fuel ratio, and reflects the learning result in the fuel injection amount. Further, the ECU 50 determines whether or not misfire has occurred in the engine 10 based on the in-cylinder pressure detected by the in-cylinder pressure sensor 40. When it is determined that misfire has occurred, air-fuel ratio learning is prohibited. In this case, it is possible to suitably suppress a decrease in accuracy of the actual air-fuel ratio control due to the influence of misfire.

  In the period from the compression stroke to the expansion stroke of the engine 10, there is a timing at which the in-cylinder pressure Pf becomes maximum. Therefore, in this period, the difference in in-cylinder pressure between combustion and misfire becomes significant. Therefore, the ECU 50 determines whether misfire has occurred based on the in-cylinder pressure Pf detected by the in-cylinder pressure sensor 40 during the period from the compression stroke to the expansion stroke. In this case, the presence or absence of misfire can be determined with high accuracy, and it is possible to suppress unnecessary prohibition of air-fuel ratio learning.

  The in-cylinder pressure Pf varies depending on the engine speed NE, the engine load EL, or the ignition timing Tig. Therefore, the ECU 50 changes the misfire determination value THA based on at least one of the engine rotation speed NE, the engine load EL, and the ignition timing Tig. In this case, since the presence or absence of misfire can be determined in consideration of the operation state of the engine 10, it is possible to suppress unnecessary prohibition of air-fuel ratio learning.

(Other embodiments)
When the ECU 50 performs air-fuel ratio learning for each cylinder 23, the prohibition or permission of air-fuel ratio learning for each cylinder 23 may be set as follows. Specifically, based on the detection value of the in-cylinder pressure sensor 40 provided in each cylinder 23, it is determined whether misfire has occurred for each cylinder. Then, the air-fuel ratio learning is prohibited for the cylinders 23 determined to have misfire, and the air-fuel ratio learning is permitted for the other cylinders.

  The ECU 50 sets the misfire determination value THA using all of the engine speed NE, the engine load EL, and the ignition timing Tig, and replaces the misfire determination value THA with at least one of the engine speed NE and the engine load EL. May be set.

  The ECU 50 may determine that misfire has occurred in the engine 10 when it is determined that the in-cylinder pressure from the latter half of the compression stroke to the first half of the expansion stroke is equal to or greater than a predetermined threshold.

  The engine 10 is not limited to the in-cylinder injection type, and may be a port injection type.

  DESCRIPTION OF SYMBOLS 10 ... Engine, 23 ... Cylinder, 40 ... In-cylinder pressure sensor, 50 ... ECU.

Claims (3)

Applied to an internal combustion engine (10) including an in-cylinder pressure detecting section (40) for detecting an in-cylinder pressure of the cylinder (23);
An air-fuel ratio controller that controls the actual air-fuel ratio of the internal combustion engine to a target air-fuel ratio;
A learning unit that performs air-fuel ratio learning when controlling the actual air-fuel ratio by the air-fuel ratio control unit;
A reflection unit for reflecting the learning result of the air-fuel ratio learning in the fuel injection amount of the internal combustion engine;
An internal combustion engine control device (50) comprising:
A misfire determination unit that determines whether misfire has occurred in the internal combustion engine based on the in-cylinder pressure detected by the in-cylinder pressure detection unit;
A control apparatus for an internal combustion engine, comprising: a prohibiting unit that prohibits the air-fuel ratio learning by the learning unit when the misfire determination unit determines that the misfire has occurred.   The said misfire determination part determines whether the said misfire has arisen based on the said in-cylinder pressure detected by the said in-cylinder pressure detection part in the period from the compression stroke of the said internal combustion engine to an expansion stroke. The internal combustion engine control device described.   The control apparatus for an internal combustion engine according to claim 1, wherein the misfire determination unit changes the misfire determination value based on at least one of a rotation speed, a load, and an ignition timing of the internal combustion engine.

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