JP2013234578A - Control method of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem wherein the possibility of causing preignition becomes high even in a combustion cycle after automatic starting when the preignition is caused in a combustion cycle before automatic stopping, and the preignition is caused in the first several explosions after the automatic starting in such a state that the automatic stopping time by an idle reduction is short and the automatic stopping is frequently repeated without sufficiently cooling an internal combustion engine in an automatic stopping time, in a control method of the internal combustion engine having idle reduction control for automatically stopping the internal combustion engine when a predetermined stopping condition is established and automatically restarting the internal combustion engine when a predetermined restarting condition is established.SOLUTION: Whether or not preignition is caused in an internal combustion engine 10 is determined from an ion current detected by an ion current detecting device 30, and the occurrence of the preignition in a combustion cycle after restarting of the internal combustion engine 10 is avoided when the preignition is caused in the combustion cycle before stopping the internal combustion engine 10.

Description

The present invention relates to a control method for an internal combustion engine having an idling stop mechanism that automatically stops the internal combustion engine when a predetermined stop condition is satisfied and automatically restarts the internal combustion engine when the predetermined restart condition is satisfied. It is about.

Conventionally, in order to save fuel and reduce exhaust gas from an internal combustion engine, when the driver depresses the brake pedal and stops the vehicle when parked or stopped at a signal, the internal combustion engine is automatically stopped and the driver starts the vehicle. Some have an idling stop mechanism that automatically restarts the internal combustion engine when the brake pedal is returned.

However, the idling stop causes the internal combustion engine to be repeatedly stopped and restarted, and each time the engine is restarted, the internal combustion engine must be rotated by the cell motor. FIG. 6 shows load characteristics with respect to the number of revolutions at the start of the internal combustion engine. The start of the internal combustion engine is rotated by the cell motor to about 200 rpm, and the start of rotation by the cell motor is in a state where the load is greatest. In addition, when the internal combustion engine is in a high temperature state, preignition that may ignite before the end of the compression stroke in the cylinder may occur, and preignition is particularly likely to occur when the internal combustion engine is at a high temperature and a high load. Therefore, the internal combustion engine has a higher probability of occurrence of pre-ignition in several ignition operations from the start by the cell motor.

Thus, if pre-ignition occurs when the internal combustion engine is started, the internal combustion engine becomes extremely overheated, causing a problem that the internal combustion engine is damaged. Several configurations have been proposed for the purpose of suppressing the occurrence of pre-ignition at the time of restart from such an idling stop. For example, Japanese Patent Application Laid-Open No. 2007-16743 (hereinafter “Patent Document 1”) is known. ing.

In Patent Document 1, the internal combustion engine is automatically stopped when a predetermined automatic stop condition is established during operation of the internal combustion engine, and the internal combustion engine is automatically activated when the predetermined automatic start condition is established during automatic stop of the internal combustion engine. In the internal combustion engine control device to be started, it is possible to self-ignite the possibility of self-ignition of the in-cylinder mixture at the automatic start after the future automatic stop based on the operating state of the internal combustion engine before the automatic stop of the internal combustion engine When the possibility of self-ignition is predicted, the cooling device (
2. Description of the Related Art There has been proposed an internal combustion engine control device that executes forced cooling control that operates an internal combustion engine cooling device and / or an intake air cooling device.

JP 2007-16743 A

However, the above-described conventional control device for an internal combustion engine has the following problems. That is, in Patent Document 1, a device that performs forced cooling control to cool an internal combustion engine when it is predicted that there is a possibility of self-ignition at the time of automatic start in the future and automatic stop of the internal combustion engine is prohibited. (
For example, an electric radiator fan that cools the cooling water of the internal combustion engine) or a device that cools the intake air (for example, an electric intake cooling fan that cools the intake air) is operated to quickly forcibly cool the internal combustion engine and the intake air. Yes. By this forced cooling, the temperature of the internal combustion engine and the intake air can be quickly lowered to a temperature range where no self-ignition occurs, the automatic stop prohibition period can be shortened, and the in-cylinder mixture at the time of automatic start can be reduced. The automatic stop frequency can be secured while preventing self-ignition of the engine, and the fuel consumption saving effect and exhaust emission reduction effect by the automatic stop can be secured, but preignition occurs during the combustion cycle before the automatic stop. If this is done, there is a high possibility that pre-ignition will occur even in the combustion cycle after the automatic start, resulting in a problem that the combustion efficiency and durability of the internal combustion engine are reduced.

In addition, in the situation where the automatic stop time due to idling stop is short, and the internal combustion engine is not sufficiently cooled within the automatic stop time and frequently repeats automatic stop, pre-ignition occurs in several ignition operations from the automatic start, Since the vibration becomes large, the driver feels uncomfortable.

The present invention has been made in view of the above problems, and in an internal combustion engine equipped with an idling stop mechanism, when pre-ignition occurs during the combustion cycle before automatic stop, pre-ignition is performed during the automatic start and after the automatic start. An object of the present invention is to provide a control method for an internal combustion engine that suppresses the occurrence of the above and prevents a decrease in combustion efficiency and durability of the internal combustion engine.

In order to solve the above problems, the present invention is configured as follows. That is, in the invention of claim 1, an internal combustion engine having a plurality of cylinders, a spark plug for igniting a mixture of fuel and air supplied into the cylinder of the cylinder, and a high voltage to the spark plug An ignition coil comprising a primary coil, a secondary coil and an iron core to be supplied, an igniter for supplying an ignition signal to the ignition coil, and an ion for detecting an ionic current generated in the ignition plug by combustion of the internal combustion engine A current detecting device; an idling stop control for automatically stopping the internal combustion engine when a predetermined stop condition is satisfied; and automatically restarting the internal combustion engine when a predetermined restart condition is satisfied; An internal combustion engine control method comprising: an ECU that performs electrical control of the internal combustion engine, wherein the ECU pre-loads the internal combustion engine from an ion current detected by the ion current detector. In addition to determining whether ignition has occurred, control is performed to avoid occurrence of pre-ignition in the combustion cycle after restarting the internal combustion engine when pre-ignition occurs in the combustion cycle before stopping the internal combustion engine An internal combustion engine control method is provided.

In the above configuration, the ECU retards the ignition signal from the igniter in the combustion cycle after restarting the internal combustion engine when pre-ignition occurs in the combustion cycle before the internal combustion engine is stopped. Also good. Further, the ECU increases the fuel injection amount so that the air-fuel ratio becomes rich in the combustion cycle after restarting the internal combustion engine when pre-ignition occurs in the combustion cycle before stopping the internal combustion engine. May be. Further, the ECU reduces the proportion of exhaust gas recirculated into the cylinder in the combustion cycle after restarting the internal combustion engine when preignition occurs in the combustion cycle before the internal combustion engine is stopped. Also good.

Further, the ECU increases the ratio of cooled exhaust gas that is recirculated into the cylinder in the combustion cycle after restarting the internal combustion engine when preignition occurs in the combustion cycle before the internal combustion engine is stopped. You may let them. Further, the ECU may operate the cooling device for less than a predetermined time after the internal combustion engine is stopped when preignition occurs in the combustion cycle before the internal combustion engine is stopped.

In addition, the internal combustion engine includes a water temperature sensor that detects a temperature of the cooling water, and the ECU performs cooling water after the internal combustion engine is stopped when pre-ignition occurs in a combustion cycle before the internal combustion engine is stopped. The cooling device may be operated until the temperature falls below a predetermined temperature. Further, the internal combustion engine includes an intake air temperature sensor that detects an intake air temperature, and the ECU has a predetermined intake air temperature after the internal combustion engine is stopped when pre-ignition occurs in a combustion cycle before the internal combustion engine is stopped. You may operate a cooling device until it becomes below the temperature of this.

The cooling device may be configured to operate a fan that blows cooling air to a radiator and / or a water pump that forcibly circulates cooling water even when the internal combustion engine is stopped.

As described above, it is determined whether or not preignition has occurred in the internal combustion engine from the ion current detected by the ion current detection device, and when the preignition occurs in the combustion cycle before the internal combustion engine is stopped, the internal combustion engine is restarted. By implementing control to avoid the occurrence of pre-ignition in the subsequent combustion cycle, when pre-ignition occurs in the combustion cycle before automatic stop in an internal combustion engine equipped with an idling stop mechanism, automatic start and automatic An internal combustion engine control method that suppresses the occurrence of pre-ignition in the combustion cycle after startup and prevents the combustion efficiency and durability of the internal combustion engine from decreasing can be realized.

Further, when pre-ignition occurs in the combustion cycle before the internal combustion engine is stopped, the cooling device is operated for a predetermined time after the internal combustion engine is stopped, and the temperature of the cooling water becomes a predetermined temperature or less after the internal combustion engine is stopped. By operating the cooling device to the minimum, the temperature of the internal combustion engine can be lowered to suppress the occurrence of pre-ignition during the automatic start and in the combustion cycle after the automatic start. Furthermore, if control is performed to avoid the occurrence of pre-ignition within the combustion cycle after the restart of the internal combustion engine, the automatic stop time due to idling stop is short, and the internal combustion engine cannot be sufficiently cooled within the automatic stop time. The occurrence of pre-ignition can be suppressed even in such a situation where automatic stop is frequently repeated.

1 is a schematic configuration diagram showing a cooling structure of an internal combustion engine according to a first embodiment of the present invention. (A) is a time chart showing the vehicle speed characteristics of the internal combustion engine according to the first embodiment, and (B) is a time chart showing the operating characteristics of the cooling device according to the first embodiment. It is a flowchart which shows the control method of the internal combustion engine which is a 1st Example. It is a flowchart which shows the control method which avoids the pre-ignition which generate | occur | produces in the internal combustion engine which is a 1st Example. It is a time chart which shows the fuel injection quantity characteristic which avoids the pre-ignition which generate | occur | produces in the internal combustion engine which is a 1st Example. It is a figure which shows the load characteristic with respect to the rotation speed at the time of start-up of an internal combustion engine.

Hereinafter, examples showing embodiments of the present invention will be described with reference to FIGS.

FIG. 1 is a schematic configuration diagram showing a cooling structure of an internal combustion engine according to a first embodiment of the present invention, (A) is a time chart showing vehicle speed characteristics of the internal combustion engine according to the first embodiment, and (B). FIG. 2 is a time chart showing the operating characteristics of the cooling device according to the first embodiment, FIG. 3 is a flowchart showing a control method of the internal combustion engine, and FIG. 3 is a control method for avoiding preignition occurring in the internal combustion engine. FIG. 4 is a flowchart showing the operation, and FIG. 5 is a time chart showing a fuel injection amount characteristic for avoiding pre-ignition occurring in the internal combustion engine.

In FIG. 1, an internal combustion engine 10 including a cylinder, a piston, and a crankshaft includes an intake manifold 80 that supplies air into the cylinder, and the intake manifold 80 measures the amount of air supplied into the cylinder. An air flow meter 82, a throttle valve 84 for adjusting the intake air supply amount into the cylinder, and an intake air temperature sensor 90 for measuring the temperature of the air taken into the cylinder. Each cylinder of the internal combustion engine 10 is connected to an ignition coil 22 for igniting an air / fuel mixture supplied from the intake manifold 80 and an ignition plug 20 for discharging a high voltage from the ignition coil 22. Has been. Furthermore, the ignition coil 22 includes a primary coil wound with a primary winding, a secondary coil wound with a secondary winding, an iron core, and an igniter 24.

The igniter 24 receives a signal from the ECU 40 that controls the internal combustion engine 10 and supplies an ignition signal to the primary coil. Further, the internal combustion engine 10 is connected to an ion current detection device 30 that detects an ion current generated in the spark plug 20 due to combustion in the cylinder.

Further, the ion current detection device 30 supplies the detected ion current to the ECU 40, and the ECU 40 is normally combusted with the ion current supplied from the ion current detection device 30 and the internal combustion engine 10. It is determined whether or not pre-ignition has occurred in the internal combustion engine 10 by comparing the ion current map at that time.

The internal combustion engine 10 is cooled by a coolant such as water, and the cooling water circulates in the cooling water passage 60 to which the internal combustion engine 10 is connected. Further, the cooling water passage 60 is provided with a water pump 70 for circulating the cooling water.

The cooling water passes through a radiator 50 connected to the cooling water passage 60. When the vehicle travels and the outside air hits the radiator 50, the cooling water passing through the radiator 50 releases heat obtained by the internal combustion engine 10. Further, a radiator fan 52 is provided to efficiently dissipate the cooling water passing through the radiator 50 even when the vehicle is stopped.

The cooling water passage 60 is provided with a water temperature sensor 54 that detects the temperature of the cooling water. Further, the ECU 40 controls the air-fuel ratio of the internal combustion engine 10, the radiator fan 52, and the water pump 70.

The ECU 40 includes an idling stop control that automatically stops the internal combustion engine 10 when a predetermined stop condition is satisfied and automatically restarts the internal combustion engine 10 when a predetermined restart condition is satisfied. ing. The predetermined stop condition is established when the driver depresses the brake pedal to stop the vehicle while the vehicle is parked or waiting for a signal, etc., and the predetermined restart condition is driven while the internal combustion engine 10 is idling stopped. It is established by returning the brake pedal so that the person starts the vehicle.

Further, the radiator fan 52 and the water pump 70 operate using the power of the battery as a power source, and can operate even when the internal combustion engine 10 is idling stopped.

2, (A) shows a time chart showing the vehicle speed characteristics of the internal combustion engine 10, wherein the internal combustion engine after idling stop is defined as one trip from the start of the internal combustion engine 10 to the first stop. 2 trips from 10 restart to the next stop. When the ECU 40 detects a pre-ignition generated in the internal combustion engine 10 during the one trip, the ECU 40 executes control to avoid the pre-ignition of the internal combustion engine 10 during the two trips. Further, as control for avoiding the occurrence of pre-ignition in the internal combustion engine 10, control for increasing the fuel injection amount of the internal combustion engine 10 to make the air-fuel ratio rich is performed.

FIG. 2B shows the operating characteristics of the cooling device comprising the water pump 70 and the radiator fan 52. When pre-ignition occurs in the internal combustion engine 10, the idling stop control is started. The water pump 70 and the radiator fan 52 are forcibly operated for a predetermined time. Furthermore, the cooling device is operated for a predetermined time or until the temperature of the internal combustion engine 10 becomes equal to or lower than a predetermined temperature, and if these conditions are satisfied, even if the internal combustion engine 10 is in idling stop control, The cooling device is stopped.

In FIG. 3, the ECU 40 rotates the cell motor to start the internal combustion engine 10 (S1), and the ion current detection device 30 detects the ion current generated in the spark plug 20 by combustion in the cylinder. (S2). The ECU 40 determines whether pre-ignition has occurred in the internal combustion engine 10 from the ion current detected by the ion current detection device 30 in (S2) (S3), and in step S3, the internal combustion engine 10 When it is determined that pre-ignition has occurred, the ECU 40 performs control to avoid pre-ignition generated in the internal combustion engine 10 (S4). Further, the ECU 40 determines whether an idling stop condition for automatically stopping the internal combustion engine 10 is satisfied (S5), and an idling stop condition for automatically stopping the internal combustion engine 10 is satisfied in (S5). If so, the ECU 40 stops the internal combustion engine 10 (S6).

Further, the ECU 40 forcibly operates the radiator fan 52 and the water pump 70 during idling stop of the internal combustion engine 10 (S7), and the ECU 40 determines the time during which the internal combustion engine 10 is stopped due to idling stop. Count (S8). Further, the water temperature sensor 54 and the intake air temperature sensor 90 detect the temperature of the cooling water in the cooling water passage 60 and the temperature of the air in the intake manifold 80, respectively (S9).

Further, the ECU 40 determines whether or not a predetermined time has elapsed from the internal combustion engine 10 counted from (S8), or the water temperature sensor 54 and the intake air temperature sensor 90 detected in (S9). It is determined whether the temperature of the cooling water and the temperature of the air in the intake manifold 80 have become equal to or lower than a predetermined temperature (S10), and the stop time of the internal combustion engine 10 has passed a predetermined time in (S10), or When the temperature of the cooling water and the temperature of the air in the intake manifold 80 are equal to or lower than a predetermined temperature, the ECU 40 controls the radiator fan 52 and the water pump 70 during idling stop of the internal combustion engine 10. Stop (S11).

The ECU 40 determines whether a condition for automatically restarting the internal combustion engine 10 from the idling stop state is satisfied (S12), and automatically restarts the internal combustion engine 10 from the idling stop in (S12). When the condition is satisfied, the ECU 40 restarts the internal combustion engine 10 (S13). Further, the ECU 40 performs control avoiding the pre-ignition that occurred until the internal combustion engine 10 stopped in (S4) (S14).

Further, in (S10), when the stop time of the internal combustion engine 10 does not pass a predetermined time, and the temperature of the cooling water and the temperature of the air in the intake manifold 80 are each equal to or higher than a predetermined temperature, The ECU 40 determines whether a condition for automatically restarting the internal combustion engine 10 from the idling stop is satisfied (S21). Further, when the condition for automatically restarting the internal combustion engine 10 from the idling stop is established in (S21), the ECU 40 restarts the internal combustion engine 10 (S13), and in (S21) the internal combustion engine 10 is restarted. When the condition for automatically restarting from the idling stop is not satisfied, the ECU 40 returns to the process of (S10).

When it is determined in (S3) that no pre-ignition has occurred in the internal combustion engine 10, the ECU 40 determines whether an idling stop condition for automatically stopping the internal combustion engine 10 is satisfied ( When the idling stop condition for automatically stopping the internal combustion engine 10 is established in S31) and (S31), the ECU 40 stops the internal combustion engine 10 (S32). Further, the ECU 40 determines whether a condition for automatically restarting the internal combustion engine 10 from the idling stop is satisfied (S33), and a condition for automatically restarting the internal combustion engine 10 from the idling stop in (S33). When is established, the ECU 40 restarts the internal combustion engine 10 (S34).

FIG. 4 (a) shows control for avoiding preignition generated in the internal combustion engine 10 in FIG. 3 (S4), and FIG. 4 (b) shows the internal combustion engine 10 in FIG. 3 (S14). The control which avoided the pre-ignition which generate | occur | produced until time stopped is shown.

4 (a), the ECU 40 increases the fuel injection amount supplied into the internal combustion engine 10 (S41), and the ion current detection device 30 is generated in the spark plug 20 by combustion in the cylinder. The ion current to be detected is detected (S42). The ECU 40 determines whether pre-ignition has occurred in the internal combustion engine 10 from the ion current detected by the ion current detection device 30 in (S42) (S43). Further, if it is determined in (S43) that no pre-ignition has occurred in the internal combustion engine 10, the ECU 40 stores the fuel injection amount supplied into the internal combustion engine 10 at that time (S44). When it is determined in (S43) that pre-ignition has occurred in the internal combustion engine 10, the ECU 40 returns to the process of (S41).

In FIG. 4B, the ECU 40 supplies the internal combustion engine with an amount of fuel equivalent to the fuel injection amount that avoids pre-ignition during one trip of the internal combustion engine 10 stored in (S44) of FIG. 10 (S51), the ion current detector 30 detects an ion current generated in the spark plug 20 due to combustion in the cylinder (S52). The ECU 40 determines whether pre-ignition is occurring in the internal combustion engine 10 from the ion current detected by the ion current detection device 30 in (S52) (S53). Further, when it is determined in (S53) that no pre-ignition has occurred in the internal combustion engine 10, the ECU 40 decreases the fuel injection amount supplied into the internal combustion engine 10 (S54), and the ECU 40 Then, it is determined whether or not the fuel injection amount decreased in (S54) is the initial fuel injection amount of the internal combustion engine 10 (S55).

If it is determined in (S53) that pre-ignition has occurred in the internal combustion engine 10, the ECU 40 increases the fuel injection amount supplied into the internal combustion engine 10 (S61). Further, when it is the initial fuel injection amount of the internal combustion engine 10 in (S55), the ECU 40 returns to the processing of (S52).

FIG. 5C is a time chart showing the presence or absence of pre-ignition generated in the internal combustion engine 10, and FIG. 5D shows a time chart showing the characteristics of the fuel injection amount supplied into the internal combustion engine 10. ing.

In FIG. 5, when preignition occurs within one trip of the internal combustion engine 10, the ECU 40 gradually increases the fuel injection amount until the preignition of the internal combustion engine 10 disappears. Further, the combustion injection amount supplied in the two trips when the idling stop is completed and the internal combustion engine 10 is restarted is the fuel in which the preignition supplied before the stop in the one trip of the internal combustion engine 10 is suppressed. Start with an amount equivalent to the injection amount. Further, the fuel injection amount is increased or decreased so that preignition does not occur within two trips of the internal combustion engine 10.

With the above configuration, when a pre-ignition generated in the internal combustion engine 10 during the one trip is detected, a control for avoiding the occurrence of the pre-ignition of the internal combustion engine 10 is executed during the two trips, thereby providing an idling stop mechanism. In the internal combustion engine 10 provided, when pre-ignition occurs in the combustion cycle before the automatic stop, the occurrence of pre-ignition is suppressed during the automatic start and in the combustion cycle after the automatic start, the internal combustion engine 10 A reduction in combustion efficiency and durability can be prevented.

Further, the combustion injection amount supplied in the two trips when the internal combustion engine 10 is restarted is started from an amount equivalent to the fuel injection amount supplied before the internal combustion engine 10 is stopped in one trip. The fuel injection amount is increased or decreased so that pre-ignition does not occur within two trips of the engine 10. Thereby, it is possible to prevent the fuel injection amount supplied in two trips from being fixed in a state where the air-fuel ratio becomes rich and the fuel consumption to deteriorate.

In addition, during the idling stop of the internal combustion engine 10, the radiator fan 52 and the water pump 70 are forcibly operated to cool the internal combustion engine 10, thereby reducing the temperature of the internal combustion engine 10 and restarting it by a cell motor. Preignition that occurs in the first few shots of the hour can be suppressed. Further, if the control for avoiding the occurrence of pre-ignition is performed in the combustion cycle after the restart from the idling stop of the internal combustion engine 10, the automatic stop time due to the idling stop is short, and the cooling is performed within the automatic stop time. The occurrence of pre-ignition can be suppressed even in a situation where the automatic stop is frequently repeated so that the internal combustion engine 10 cannot be sufficiently cooled by the apparatus.

Further, when the internal combustion engine 10 is stopped for a predetermined time, or when the temperature of the cooling water and the temperature of the air in the intake manifold 80 are respectively equal to or lower than the predetermined temperature, the internal combustion engine 10 By stopping the radiator fan 52 and the water pump 70 during idling stop, it is possible to prevent the temperature of the internal combustion engine 10 from being excessively lowered and the fuel efficiency of the internal combustion engine 10 after restarting from being deteriorated.

As a modification of the first embodiment, as a method for determining the occurrence of preignition in the internal combustion engine 10 from the ion current detected by the ion current detection device 30, for example, normal combustion is performed from the peak value of the detected ion current. It may be changed as appropriate depending on design circumstances, such as determining whether or not the operation has been performed. Further, as the cooling device for the internal combustion engine 10 during idling stop, the water pump 70 for circulating the cooling water and the radiator fan 52 that applies wind to the radiator 50 even when the vehicle is stopped are provided. As long as the temperature of the internal combustion engine 10 can be lowered even when the engine 10 is stopped, it may be appropriately added or changed depending on the design circumstances. Further, as control for avoiding pre-ignition generated in the internal combustion engine 10, the ignition signal from the igniter 24 is retarded in addition to control for increasing the fuel injection amount of the internal combustion engine 10 to make the air-fuel ratio rich. In a method that can suppress the pre-ignition of the internal combustion engine 10, such as control, control for reducing the ratio of the amount of exhaust gas recirculated into the cylinder, or control for increasing the ratio of cooled exhaust gas recirculated into the cylinder If there are, you may change suitably.

In addition, the condition for the automatic stop of the internal combustion engine 10 by idling stop is that the driver can stop idling more safely besides stopping the vehicle by the driver stepping on the brake pedal while the vehicle is parked or waiting for a signal, etc. The conditions may be changed as appropriate. Further, the condition for the automatic restart of the internal combustion engine 10 from the idling stop is that the driver is safer than returning the brake pedal to start the vehicle during the idling stop of the internal combustion engine 10. In addition, the conditions may be appropriately changed to allow the restart from the idling stop.

Further, the cooling device is operated for a predetermined time or until the temperature of the internal combustion engine 10 becomes a predetermined temperature or less, respectively. The predetermined time and the predetermined temperature are the displacement of the internal combustion engine 10 and the cylinder. It may be determined by a configuration such as a number. Further, in the internal combustion engine 10, the cooling time of the internal combustion engine 10 when the cooling by the cooling device passes a predetermined time, or the temperature of the cooling water and the temperature of the air in the intake manifold 80 are a predetermined temperature. When it is performed until the following, the control content for avoiding the occurrence of pre-ignition performed within two trips of the internal combustion engine 10 may be changed, assuming that the temperature of the internal combustion engine 10 has sufficiently decreased.

10: Internal combustion engine
20: Spark plug
22: Ignition coil
24: Igniter
30: Ion current detector
40: ECU
50: Radiator
52: Radiator fan
54: Water temperature sensor
60: Cooling water passage
70: Water pump
80: Intake manifold
82: Air flow meter
84: Throttle valve
90: Intake air temperature sensor

Claims (9)

An internal combustion engine having a plurality of cylinders, a spark plug for igniting a mixture of fuel and air supplied into the cylinder of the cylinder, a primary coil and a secondary coil for supplying high voltage to the spark plug, And an ignition coil comprising an iron core, an igniter for supplying an ignition signal to the ignition coil, an ion current detection device for detecting an ion current generated in the ignition plug by combustion of the internal combustion engine, and a predetermined stop condition An idling stop control that automatically stops the internal combustion engine when the condition is satisfied and automatically restarts the internal combustion engine when a predetermined restart condition is satisfied; an ECU that performs electrical control of the internal combustion engine; An internal combustion engine control method comprising:
The ECU determines whether pre-ignition has occurred in the internal combustion engine from the ion current detected by the ion current detection device, and when the pre-ignition has occurred in a combustion cycle before the internal combustion engine is stopped. A control method for an internal combustion engine, characterized in that control for avoiding the occurrence of pre-ignition is performed in a combustion cycle after restarting the engine. The ECU retards an ignition signal from the igniter in a combustion cycle after restarting the internal combustion engine when pre-ignition occurs in the combustion cycle before stopping the internal combustion engine. Item 6. A method for controlling an internal combustion engine according to Item 1. The ECU increases the fuel injection amount so that the air-fuel ratio becomes rich in the combustion cycle after restarting the internal combustion engine when pre-ignition occurs in the combustion cycle before stopping the internal combustion engine. The method for controlling an internal combustion engine according to claim 1, characterized in that: The ECU reduces a ratio of exhaust gas recirculated into the cylinder in a combustion cycle after restarting the internal combustion engine when preignition occurs in the combustion cycle before the internal combustion engine is stopped. The method for controlling an internal combustion engine according to claim 1. The ECU increases a ratio of cooled exhaust gas recirculated into the cylinder in a combustion cycle after restarting the internal combustion engine when preignition occurs in the combustion cycle before the internal combustion engine is stopped. The method of controlling an internal combustion engine according to claim 1. 6. The ECU according to claim 1, wherein when the pre-ignition occurs in the combustion cycle before the internal combustion engine is stopped, the ECU operates the cooling device for less than a predetermined time after the internal combustion engine is stopped. The method for controlling an internal combustion engine according to claim 1. The internal combustion engine includes a water temperature sensor that detects the temperature of cooling water,
The ECU operates the cooling device until the temperature of the cooling water becomes equal to or lower than a predetermined temperature after the stop of the internal combustion engine when pre-ignition occurs in the combustion cycle before the stop of the internal combustion engine. The method for controlling an internal combustion engine according to any one of claims 1 to 6. The internal combustion engine includes an intake air temperature sensor that detects an intake air temperature,
The ECU operates a cooling device until an intake air temperature becomes a predetermined temperature or less after the internal combustion engine is stopped when preignition occurs in a combustion cycle before the internal combustion engine is stopped. The method for controlling an internal combustion engine according to any one of 1 to 7. 9. The cooling device according to claim 6, wherein the cooling device operates a fan that blows cooling air to a radiator and / or a water pump that forcibly circulates cooling water even when the internal combustion engine is stopped. The control method of the internal combustion engine of any one of Claims 1.

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