JP6079573B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine. In particular, the present invention relates to an improvement in ignition retard control executed after a fuel cut cancellation condition is satisfied.

  In an internal combustion engine (hereinafter referred to as an engine) mounted on a vehicle, fuel cut control for stopping fuel injection from an injector is performed during deceleration of the vehicle. Specifically, when the amount of depression of the accelerator pedal by the driver is “0” (accelerator OFF) and the engine speed is within a predetermined range (more than the fuel cut speed), the fuel cut The fuel injection from the injector is stopped because the condition is satisfied. As a result, a sense of deceleration of the vehicle is ensured and fuel consumption is reduced. In addition, when a predetermined fuel cut cancellation condition (for example, when the engine rotational speed is reduced to the fuel injection return rotational speed) is satisfied, the fuel injection of the injector is resumed.

  Further, when the fuel injection is restarted, the ignition timing of the spark plug is retarded from the normal ignition timing in order to prevent the fluctuation of the engine torque from becoming extremely large.

  Further, in this ignition delay control, when the number of ignitions of the spark plug after the fuel cut cancellation condition is satisfied reaches a predetermined value, the ignition timing is advanced toward the normal ignition timing. For example, in Patent Document 1, each time an ignition operation is performed from the state where the fuel cut cancellation condition is satisfied and the ignition timing is retarded, the ignition timing is advanced by a predetermined amount toward the normal ignition timing. Is disclosed.

JP 2010-249053 A

  However, as described above, the control for advancing the ignition timing simply based on the number of ignitions of the spark plug has the following problems.

  When the fuel cut cancellation condition is satisfied, an ignition timing may be reached before reaching the fuel injection timing in a certain cylinder. In this cylinder, the ignition operation is performed in a state where no fuel is present. Done. That is, there is a cylinder that performs an ignition operation that does not contribute to combustion. For this reason, depending on the timing at which the fuel cut cancellation condition is satisfied, the timing at which engine torque is actually generated varies due to the presence of a cylinder that performs an ignition operation that does not contribute to the combustion.

  In the conventional technology, an ignition operation (ignition operation contributing to combustion) performed in a state where fuel exists in the cylinder and an ignition operation performed in a state where fuel does not exist in the cylinder (Ignition operation that does not contribute to combustion) is treated equally, and the ignition timing is advanced based on the number of ignition operations.

  For this reason, due to the presence of the ignition operation that does not contribute to the combustion, the point in time when the ignition operation that contributes to the combustion is performed (the timing at which the engine torque is actually generated) and the advance side of the ignition timing. There is a possibility that the transition start timing substantially coincides with this, and in this case, the engine output fluctuates greatly and a shock may occur.

  Considering this point, it is conceivable to set a longer period for retarding the ignition timing. However, this slows the increase in engine output after the fuel cut release condition is satisfied, and the driver's Responsiveness to the output request is deteriorated.

  The present invention has been made in view of such points, and an object of the present invention is to provide a control device for an internal combustion engine capable of optimizing an ignition delay amount after a fuel cut cancellation condition is satisfied. There is to do.

-Solution principle of the invention-
The solution principle of the present invention taken in order to achieve the above object is that the ignition timing is determined based on the number of ignition operations contributing to combustion from the state where the fuel cut release condition is satisfied and the ignition timing is retarded. It is to determine the timing for advancing.

-Solution-
Specifically, the present invention is premised on a control device for an internal combustion engine that retards the ignition timing of a spark plug when a fuel cut release condition is satisfied during fuel cut. With respect to the control device for the internal combustion engine, the ignition plug is ignited in a state where substantially the entire amount of fuel injected from the injector is introduced into the cylinder and a predetermined amount of fuel is present in the cylinder. The ignition operation in this case is an ignition operation of a spark plug that contributes to combustion, and only a part of the fuel injected from the injector is introduced into the cylinder and there is no predetermined amount of fuel in the cylinder. the ignition operation when the ignition operation of the ignition plug is performed, when the ignition operation of the ignition plug does not contribute to the combustion, definitive after the fuel cut cancellation condition is satisfied, the ignition of the combustion contributing spark plug Of the ignition plug ignition operation that does not contribute to the operation and combustion, the number of times of only the ignition operation of the ignition plug that contributes to the combustion is integrated, and the ignition delay amount is decreased when the integrated value reaches a predetermined value age There.

  When the fuel cut cancellation condition is satisfied during the fuel cut due to this specific matter, the number of ignition operations of the spark plug that contribute to the combustion (ignition operation in which the output of the internal combustion engine is actually obtained) is integrated thereafter. That is, the number of times that the ignition operation of the spark plug is executed in a state where a predetermined amount of fuel is present in the cylinder is integrated. In the period until the integrated value reaches the predetermined value, the ignition timing has not yet shifted to the advance side, so the output of the internal combustion engine is kept relatively low. When the integrated value reaches a predetermined value, an operation for decreasing the ignition retard amount is started, and the ignition timing of the spark plug is returned to the normal ignition timing. The output of the internal combustion engine gradually increases as the ignition retard amount reduction operation starts. Thus, after the state in which the output of the internal combustion engine is obtained is continued, the ignition retard amount reduction operation is started so that the output of the internal combustion engine gradually increases. An increase in fluctuation can be suppressed. In addition, since the period during which the ignition timing is retarded is not set longer than necessary, the output of the internal combustion engine after the fuel cut cancellation condition is satisfied can be obtained according to the driver's request. Is possible.

  In the present invention, when the fuel cut cancellation condition is satisfied and the ignition timing is retarded, the ignition retard amount is decreased when the number of ignition operations contributing to combustion reaches a predetermined value. For this reason, it can suppress that the fluctuation | variation of the output of an internal combustion engine becomes large.

It is a figure which shows schematic structure of the engine and intake / exhaust system which concern on embodiment. It is a block diagram which shows the control system of an engine. It is a flowchart figure which shows the procedure of combustion contribution ignition frequency count operation | movement. It is a figure for demonstrating the fuel-injection timing which contributes to combustion, and the fuel-injection timing which does not contribute to combustion. It is a flowchart figure which shows the procedure of ignition timing control after fuel injection return. It is a timing chart figure which shows each of the change of the F / C request | requirement signal in embodiment, the fuel injection timing of each cylinder, ignition timing, and the change of ignition retard amount. It is a timing chart figure which shows each of the change of the F / C request | requirement signal in a prior art, the fuel injection timing and ignition timing of each cylinder, and the change of ignition retard amount.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, a case where the control device according to the present invention is applied to a four-cylinder gasoline engine (internal combustion engine) for an automobile will be described.

-Engine-
FIG. 1 is a diagram showing a schematic configuration of an engine 1 and an intake / exhaust system according to the present embodiment. In FIG. 1, only the configuration of one cylinder of the engine 1 is shown.

  The engine 1 in this embodiment is, for example, a 4-cylinder gasoline engine, and includes a piston 12 that forms a combustion chamber 11 and a crankshaft 13 that is an output shaft. The piston 12 is connected to the crankshaft 13 via a connecting rod 14, and the reciprocating motion of the piston 12 is converted into rotation of the crankshaft 13 by the connecting rod 14.

  A signal rotor 15 having a plurality of protrusions 16 on the outer peripheral surface is attached to the crankshaft 13. A crank position sensor 71 is disposed near the side of the signal rotor 15. The crank position sensor 71 is, for example, an electromagnetic pickup, and generates a pulsed signal (output pulse) corresponding to the protrusion 16 of the signal rotor 15 when the crankshaft 13 rotates.

  A water temperature sensor 72 for detecting the engine water temperature (cooling water temperature) is disposed in the cylinder block 17 of the engine 1.

  An ignition plug (ignition plug) 2 is disposed in the combustion chamber 11 of the engine 1. The ignition timing of the spark plug 2 is adjusted by the igniter 21. The igniter 21 is controlled by an engine ECU (Electronic Control Unit) 6.

  An intake passage 3 and an exhaust passage 4 are connected to the combustion chamber 11 of the engine 1. An intake valve 31 is provided between the intake passage 3 and the combustion chamber 11. By opening and closing the intake valve 31, the intake passage 3 and the combustion chamber 11 are communicated or blocked. An exhaust valve 41 is provided between the exhaust passage 4 and the combustion chamber 11. By opening and closing the exhaust valve 41, the exhaust passage 4 and the combustion chamber 11 are communicated or blocked. The opening / closing drive of the intake valve 31 and the exhaust valve 41 is performed by each rotation of an intake camshaft and an exhaust camshaft (both not shown) to which the rotation of the crankshaft 13 is transmitted.

  An air cleaner 32, an air flow meter 73, an intake air temperature sensor 74 (built in the air flow meter 73), and an electronically controlled throttle valve 33 are disposed in the intake passage 3. The throttle valve 33 is driven by a throttle motor 34. The opening degree of the throttle valve 33 is detected by a throttle opening degree sensor 75.

  An injector 35 is disposed in the intake passage 3. The injector 35 is supplied with fuel at a predetermined pressure from a fuel tank by a fuel pump, and injects the fuel into the intake passage 3. This injected fuel is mixed with intake air to form an air-fuel mixture and introduced into the combustion chamber 11 of the engine 1. The air-fuel mixture (fuel + air) introduced into the combustion chamber 11 passes through the compression stroke of the engine 1 and is then ignited and burned by the spark plug 2. The combustion of the air-fuel mixture in the combustion chamber 11 causes the piston 12 to reciprocate and the crankshaft 13 to rotate.

  Two three-way catalysts 42 and 43 are disposed in the exhaust passage 4 of the engine 1. These three-way catalysts 42 and 43 can purify HC, CO and NOx in the exhaust gas.

  An air-fuel ratio sensor 76 is disposed upstream of the three-way catalyst 42 in the exhaust passage 4 and an oxygen sensor 77 is disposed downstream. The output signals of the air-fuel ratio sensor 76 and the oxygen sensor 77 are each A / D converted and then input to the engine ECU 6.

-Description of control block-
The operating state of the engine 1 is controlled by the engine ECU 6. As shown in FIG. 2, the engine ECU 6 includes a CPU (Central Processing Unit) 61, a ROM (Read Only Memory) 62, a RAM (Random Access Memory) 63, a backup RAM 64, and the like.

  The ROM 62 stores various control programs, maps that are referred to when the various control programs are executed, and the like. The CPU 61 executes arithmetic processing based on various control programs and maps stored in the ROM 62. The RAM 63 is a memory that temporarily stores calculation results in the CPU 61, data input from each sensor, and the like. The backup RAM 64 is a nonvolatile memory that stores data to be saved when the engine 1 is stopped.

  The ROM 62, CPU 61, RAM 63, and backup RAM 64 are connected to each other via a bus 67, and are also connected to an external input circuit 65 and an external output circuit 66. In addition to the crank position sensor 71, the water temperature sensor 72, the air flow meter 73, the intake air temperature sensor 74, the throttle opening sensor 75, the air-fuel ratio sensor 76, the oxygen sensor 77, the external input circuit 65 includes an accelerator opening sensor 78, A cam angle sensor 79, a knock sensor 7A, and the like are connected. On the other hand, a throttle motor 34 for driving the throttle valve 33, the injector 35, the igniter 21 and the like are connected to the external output circuit 66. Since the function of each sensor is well-known, description here is abbreviate | omitted.

  The engine ECU 6 executes various controls of the engine 1 based on detection signals from the various sensors. For example, ignition timing control of the spark plug 2, fuel injection control of the injector 35 (air-fuel ratio feedback control based on the outputs of the air-fuel ratio sensor 76 and the oxygen sensor 77), drive control of the throttle motor 34, and the like are executed.

-Basic operation of ignition timing control-
The basic operation of the ignition timing control of the spark plug 2 includes the knock sensor 7A while correcting the advance of the ignition timing so that the ignition timing approaches MBT (Minimum Spark Advance for Best Torque). When knocking is detected by the control, the control is performed such that the knocking is eliminated by correcting the retard of the ignition timing.

-Outline of fuel cut control-
The engine ECU 6 also performs the following fuel cut control.

  In this fuel cut control, the engine speed calculated based on the signal from the crank position sensor 71 is equal to or higher than a predetermined value (fuel cut speed: 1000 rpm, for example) and detected by the accelerator opening sensor 78. When the opening degree of the accelerator pedal is “0” (accelerator OFF), it is determined that the fuel cut condition is satisfied, and the fuel injection from the injector 35 is stopped. As a result, fuel consumption can be reduced and exhaust emission can be improved.

  When the vehicle speed is reduced during the fuel cut and the engine speed is lower than the fuel cut speed, the fuel cut canceling condition is satisfied and the fuel cut is stopped to prevent engine stall. Then, the fuel injection from the injector 35 is resumed. Even when the accelerator pedal is depressed during fuel cut (acceleration), the fuel cut is stopped and fuel is injected from the injector 35, assuming that the fuel cut release condition is satisfied.

-Fuel injection return control-
Next, fuel injection return control, which is an operation characteristic of the present embodiment, will be described. This fuel injection return control is control when fuel injection is resumed when the fuel cut cancellation condition is satisfied during the fuel cut.

  First, the outline of this fuel injection return control will be described. When the fuel cut cancellation condition is satisfied and the fuel injection from the injector 35 is resumed, the ignition timing of the spark plug 2 is controlled by the above-described ignition timing control in order to prevent the engine torque fluctuation from becoming extremely large. Is retarded from the normal ignition timing determined by. Then, from the state in which the ignition timing is retarded, the number of ignition operations that contribute to combustion (the count value of a combustion contribution ignition number counter described later) is accumulated, and the accumulated value reaches a predetermined value. At this time, the ignition retard amount is decreased (the ignition timing is advanced toward the normal ignition timing). Since such fuel injection return control is performed, in the control device according to the present invention, the input signal includes an output signal of the crank position sensor 71, a control signal of the fuel injection timing, and execution of an ignition operation. Various signals such as signals may be mentioned. The control device is configured to obtain an ignition delay amount based on these signals and output an ignition timing command signal corresponding to the ignition delay amount as an output signal.

  Next, the fuel injection return control will be specifically described with reference to a flowchart. The flowchart shown in FIG. 3 is a flowchart showing the procedure of the combustion contribution ignition frequency counting operation. Further, the flowchart shown in FIG. 5 is a flowchart showing a procedure of ignition timing control after fuel injection return. These routines are repeatedly executed at a predetermined cycle time while the vehicle is running, for example.

  First, the combustion contribution ignition frequency counting operation will be described with reference to FIG. In step ST1, the engine operating state quantity is acquired. Examples of the engine operating state quantity include engine rotational speed information, fuel injection timing information, ignition operation execution information, and the like. The engine speed is calculated based on the output signal of the crank position sensor 71. Information on the fuel injection timing is obtained from a fuel injection command signal output from the engine ECU 6. The execution information of the ignition operation is acquired from an ignition command signal output from the engine ECU 6.

  In step ST2, based on the fuel injection command signal, it is determined whether or not the fuel injection timing in the target cylinder (cylinder in which fuel injection from the injector 35 has been performed) among the plurality of cylinders is the combustion contribution timing. . The combustion contribution timing is a combustion stroke in which substantially the entire amount of fuel injected from the injector 35 is introduced into the cylinder in a target cylinder (cylinder about to reach the combustion stroke), and the fuel is immediately performed. This is the fuel injection timing that contributes to the combustion of the fuel. This will be specifically described below.

  FIG. 4 shows the crank position sensor in the period from the compression top dead center (compression TDC) of the piston 12 of the target cylinder to the crank rotation angle of 720 ° (compression top dead center of the piston 12 in the next cycle of the same cylinder). 71 output signals are represented. The 360 ° timing in the figure is the intake top dead center (intake TDC) of the piston 12 when the exhaust stroke ends and the intake stroke starts. In FIG. 4, the period I in the figure is the opening period of the intake valve 31.

  For example, when the fuel injection period is the period A in the figure, the fuel injection from the injector 35 has been completed before the intake valve 31 is closed. In this case, substantially the entire amount of injected fuel is within the cylinder. Therefore, it is assumed that the fuel injection in the period A is performed at the combustion contribution timing. On the other hand, for example, when the fuel injection period is the period B in the figure, the fuel injection from the injector 35 continues despite the intake valve 31 being closed, and in this case, the injected fuel Therefore, it is assumed that the fuel injection in this period B is not performed at the combustion contribution timing. Examples of the fuel injection operation in the fuel injection period B include a fuel injection operation performed to ensure a large amount of fuel in the cylinder in the next cycle of the same cylinder.

  When the fuel injection timing from the injector 35 is the combustion contribution timing and YES is determined in step ST2, the process proceeds to step ST3, the combustion contribution flag of the target cylinder is turned ON, and then the process proceeds to step ST4. This combustion contribution flag is stored in advance in the engine ECU 6. On the other hand, when the fuel injection timing from the injector 35 is not the combustion contribution timing but NO is determined in step ST2, the routine proceeds to step ST4 without turning on the combustion contribution flag of the target cylinder.

  In step ST4, it is determined whether or not the current operation state of the engine 1 is executing fuel cut (F / C) control and fuel that contributes to combustion does not exist in all the cylinders. That is, if fuel cut control is being continued, or if any cylinder has not yet reached the fuel injection timing immediately after the fuel cut release condition is satisfied, YES is determined in step ST4. Become.

  If YES is determined in step ST4, the count value of the combustion contribution ignition number counter stored in advance in the engine ECU 6 is cleared and the process returns. That is, even if the ignition operation is performed in any of the cylinders, it is determined that the ignition operation does not contribute to combustion, and the count value of the combustion contribution ignition frequency counter is cleared.

  On the other hand, if NO is determined in step ST4, the process proceeds to step ST6 to determine whether or not the ignition operation of the spark plug 2 has been executed. That is, whether or not the fuel cut control is released and the ignition operation is executed in a state where the fuel injection from the injector 35 is executed for any of the cylinders (whether or not the ignition operation contributing to combustion is performed). Determine. This determination is made according to the presence or absence of an ignition command signal from the engine ECU 6 to the igniter 21.

  When the ignition operation of the spark plug 2 has not been executed yet and NO is determined in step ST6, execution of the ignition operation is awaited.

  When the ignition operation of the spark plug 2 is executed and a YES determination is made in step ST6, the process proceeds to step ST7, the count value of the combustion contribution ignition number counter is incremented, and the combustion contribution of the target cylinder is performed. The flag is turned off and the process returns.

  When the ignition operation that does not contribute to combustion is performed by repeating such an operation, the count value of the combustion contribution ignition number counter is cleared, while the ignition operation that contributes to combustion is started. Each time the ignition operation is performed, the count value of the combustion contribution ignition counter is incremented.

  Next, ignition timing control after fuel injection return will be described with reference to the flowchart of FIG. In step ST11, it is determined whether or not a post-return ignition timing control flag stored in advance in the engine ECU 6 is ON. The post-return ignition timing control flag is a flag that is turned ON when the fuel cut cancellation condition is satisfied and the ignition timing retarding operation is started, as will be described later.

  If the fuel cut cancellation condition has not yet been established, the post-return ignition timing control flag is OFF. In this case, a NO determination is made in step ST11 and the process proceeds to step ST12. In step ST12, it is determined whether or not the retardation amount initial value setting condition is satisfied. The initial condition for setting the retard amount is satisfied when the fuel cut cancellation condition is satisfied. In other words, the initial condition of the retard amount is set to set the ignition retard amount (retard amount initial value) at the time when the fuel cut cancellation condition is satisfied and the ignition timing control is started after the fuel injection is restored. Is the condition.

  If the retardation amount initial value setting condition is not satisfied and the determination is NO in step ST12, the process returns.

  On the other hand, if the retard amount initial value setting condition is satisfied and YES is determined in step ST12, the process proceeds to step ST13, and the retard amount initial value is set. The initial value of the retardation amount is defined in advance by experiments and simulations.

  Thereafter, the process proceeds to step ST14, and the post-return ignition timing control flag is turned ON.

  In step ST15, it is determined whether or not the count value of the combustion contribution ignition number counter integrated by the combustion contribution ignition number counting operation is less than a predetermined value α. This predetermined value α is also defined in advance by experiments and simulations, and is set to “4”, for example. This value is not limited to this.

  If the count value of the combustion contribution ignition number counter is less than the predetermined value α and YES is determined in step ST15, the process proceeds to step ST16, and a predetermined amount “A” with respect to the previous value of the ignition retard amount after return. Only this is added, and this is set to the ignition delay amount after the current return, and the process returns. For example, the predetermined amount “A” is set to “0”. That is, when the count value of the combustion contribution ignition frequency counter is less than the predetermined value α, the ignition retardation amount after return is not changed.

  As described above, when the count value of the combustion contribution ignition frequency counter is less than the predetermined value α, in the next routine, the post-return ignition timing control flag is already ON, and therefore YES is determined in step ST11. Then, the process proceeds to step ST15. In step ST15, as described above, it is determined whether or not the count value of the combustion contribution ignition number counter is less than a predetermined value α. If the count value of the combustion contribution ignition frequency counter is still less than the predetermined value α, a YES determination is made in step ST15, and the process returns without changing the post-return ignition retard amount in step ST16. Thus, until the count value of the combustion contribution ignition number counter reaches the predetermined value α, the post-return ignition retard amount does not change and is maintained at the retard amount initial value.

  On the other hand, if the count value of the combustion contribution ignition counter is equal to or greater than the predetermined value α and the determination is NO in step ST15, the process proceeds to step ST17, where the predetermined value “B” is set with respect to the previous value of the ignition retard amount after return. ”Is added, and this is set to the ignition delay amount after the current return to advance the ignition timing of the spark plug 2. The predetermined amount “B” is set as a negative value having an absolute value larger than that of “A”. For example, the crank angle is set to “−1 °”. As a result, the ignition timing of the spark plug 2 is shifted to the advance side by “1 °”. This value is not limited to this, and is defined in advance by experiments and simulations.

  Thereafter, the process proceeds to step ST18, where it is determined whether or not the post-return ignition delay amount (ignition timing shifted to the advance side) obtained in step ST17 has reached the normal ignition timing. The ignition timing at the normal time is an ignition timing whose advance angle is corrected so as to approach the MBT according to the knocking detection signal from the knock sensor 7A as described above, and is defined in advance by experiments and simulations.

  If the post-return ignition retard amount is not yet the normal ignition timing, NO is determined in step ST18, and the process returns.

  In the next routine, since the post-return ignition timing control flag is already ON, YES is determined in step ST11 and the process proceeds to step ST15. In step ST15, as described above, it is determined whether or not the count value of the combustion contribution ignition number counter is less than a predetermined value α. As described above, since the count value of the combustion contribution ignition frequency counter is already equal to or greater than the predetermined value α, NO is determined in step ST15 and the process proceeds to step ST17. In step ST17, a predetermined amount “B” is further added to the previous value of the post-return ignition delay amount (the post-return ignition delay amount added by the predetermined amount “B” in the previous routine). After the return, the ignition timing of the spark plug 2 is further advanced by setting the ignition retard amount. Then, in step ST18 again, it is determined whether or not the post-return ignition delay amount (ignition timing shifted to the advance side) obtained in step ST17 has become the ignition timing in the normal time.

  When such an operation is repeated and the post-return ignition delay amount reaches the ignition timing at the normal time, YES is determined in step ST18, and the process proceeds to step ST19. In this step ST19, the ignition timing control of the spark plug 2 is returned to the normal ignition timing control. Further, the post-return ignition timing control flag is turned off.

  As described above, when the fuel cut cancellation condition is satisfied and the ignition timing control is started after the fuel injection is restored, the ignition timing is set to the retard amount until the count value of the combustion contribution ignition frequency counter reaches the predetermined value α. The initial value is maintained. When the count value of the combustion contribution ignition counter reaches a predetermined value α, the ignition timing is advanced, and when it is advanced to the normal ignition timing, the normal ignition timing control is restored. Yes.

  FIG. 6 is a timing chart showing changes in the F / C (fuel cut) request signal, changes in the fuel injection timing and ignition timing of each cylinder (# 1 to # 4), and changes in the ignition retard amount in the present embodiment. is there. FIG. 7 is a timing chart showing the change in the F / C request signal, the fuel injection timing and the ignition timing of each cylinder, and the change in the ignition retard amount in the above-described prior art. Timing T1 in these figures is the timing when the fuel cut cancellation condition is satisfied. In these timing charts, F represents the fuel injection timing, and S represents the ignition timing. The broken lines in these timing charts indicate the timing at which the fuel injection and ignition operations are performed when the fuel cut control is not being performed (the fuel injection and ignition operations are not actually performed because the fuel cut control is being performed). ). In addition, ignition operation that does not contribute to combustion (ignition operation in a state where a predetermined amount of fuel does not exist in the cylinder) is indicated by a thin solid line, and ignition operation that contributes to combustion (a predetermined amount of fuel exists in the cylinder) Ignition operation in the state of being) is represented by a solid thick line. Moreover, the dashed-dotted line in FIG. 6 is the said combustion contribution flag. In these drawings, the advance correction of the ignition timing is started when the number of ignition times reaches “4 times”.

  In the prior art shown in FIG. 7, the ignition [1] in the fourth cylinder and the ignition [2] in the second cylinder after the fuel cut cancellation condition is satisfied are in a state in which no fuel exists in the cylinder. Ignition operation. That is, the ignition operation does not contribute to combustion. After such an ignition operation that does not contribute to combustion is performed, ignition [3] in the first cylinder and ignition [4] in the third cylinder, which are ignition operations that contribute to combustion, are performed, and this third cylinder The transition of the ignition timing to the advance side has started from the time when ignition [4] is performed at (timing T3 in FIG. 7). That is, although the ignition operation that contributes to combustion is still performed “twice”, the transition of the ignition timing to the advance side has started. For this reason, the fluctuation of the engine output becomes large and a shock may occur.

  On the other hand, in the present embodiment shown in FIG. 6, ignition [1] in the first cylinder and ignition [2] in the third cylinder are ignition operations that contribute to combustion after the fuel cut cancellation condition is satisfied. ], The ignition [3] in the fourth cylinder and the ignition [4] in the second cylinder are sequentially performed, and the ignition timing is shifted to the advance side from the time when the ignition [4] in the second cylinder is performed. Has started. In other words, the ignition operation contributing to combustion is performed “four times”, so that the transition from the state where the engine torque is sufficiently generated to the advance side of the ignition timing has started (timing T2 in FIG. 6). For this reason, it can suppress that the fluctuation | variation of an engine output becomes large, and generation | occurrence | production of a shock can be prevented.

  As described above, in the present embodiment, when the fuel cut cancellation condition is satisfied during the fuel cut, the number of ignition operations contributing to combustion is integrated thereafter. That is, the number of times that the ignition operation is executed in a state where fuel exists in the cylinder is integrated. In the period until the integrated value reaches the predetermined value, the ignition timing has not yet shifted to the advance side, so the output of the engine 1 is kept relatively low. Then, when the integrated value reaches a predetermined value, the ignition retard amount decreasing operation is started, and the ignition timing of the spark plug 2 is returned to the normal ignition timing. Thus, after the state in which the output of the engine 1 is obtained is continued, the ignition retard amount reduction operation is started so that the output of the engine 1 gradually increases. An increase in fluctuation can be suppressed. In addition, since the period during which the ignition timing is retarded is not set longer than necessary, the output of the engine 1 after the fuel cut cancellation condition is satisfied can be obtained according to the driver's request. Is possible.

-Other embodiments-
In the embodiment described above, the case where the present invention is applied to an in-line four-cylinder gasoline engine for automobiles has been described. The present invention is not limited to this, and can be applied to an engine applied to other than automobiles. Further, the number of cylinders and the type of engine (V type, horizontally opposed type, etc.) are not particularly limited.

  Moreover, although the said embodiment demonstrated the case where this invention was applied to the conventional vehicle (vehicle which mounted only the engine as a driving force source), with respect to a hybrid vehicle (vehicle which mounted the engine and the electric motor as a driving force source). However, the present invention is applicable.

  The present invention is applicable to control of the ignition retard amount after the fuel cut cancellation condition of the engine is satisfied.

1 Engine 2 Spark plug
21 Igniter 35 Injector 6 Engine ECU

Claims (1)

In the control device for an internal combustion engine that retards the ignition timing of the spark plug when the fuel cut release condition is satisfied during the fuel cut,
The ignition operation when the ignition plug is ignited in a state where substantially the entire amount of fuel injected from the injector is introduced into the cylinder and a predetermined amount of fuel is present in the cylinder contributes to combustion. The ignition operation of the ignition plug is performed in a state where only a part of the fuel injected from the injector is introduced into the cylinder and there is no predetermined amount of fuel in the cylinder. The ignition operation of the spark plug that does not contribute to combustion is assumed to be the ignition operation of the spark plug that does not contribute to combustion after the fuel cut release condition is satisfied . Among the ignition operations, the number of times of only the ignition operation of the spark plug that contributes to the combustion is integrated, and the ignition delay amount is decreased when the integrated value reaches a predetermined value. Internal combustion machine Control device.

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