JPH1193757A - Control device for internal combustion engine - Google Patents

Abstract

(57) [Problem] To easily and reliably detect the occurrence of preignition in an internal combustion engine and suppress the preignition to protect the internal combustion engine. SOLUTION: Knock is detected by using a knock sensor, and the knocking is suppressed by, for example, retard control of the ignition timing. When knocking continues for a predetermined period despite the control of knocking suppression, this is detected. It is detected as the occurrence of preignition. Then, when the occurrence of preignition is detected, for example, the output of the cylinder is reduced by controlling the decrease of the fuel injection amount or intake air amount for the cylinder in which preignition has occurred.
In particular, when the preignition is light, the output is reduced to suppress the preignition, and when the preignition is heavy, the output is stopped to prevent engine damage.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects a preignition in which an air-fuel mixture is ignited and burned before a regular ignition timing in an internal combustion engine, and prevents damage to the internal combustion engine by detecting the preignition easily. The present invention relates to a control device for an internal combustion engine that can estimate a margin of heat value to a minimum.

[0002]

2. Related Art In a spark ignition type internal combustion engine, a preignition in which an air-fuel mixture burns before a regular ignition timing by a spark plug may occur. The preignition is a phenomenon in which an air-fuel mixture introduced into the combustion chamber is ignited and burned at a tip portion (glass part) of a spark plug or a hot surface of deposited carbon or the like in the combustion chamber. Knocking in which such preignition occurs occurs, and this knocking destroys the thermal boundary layer of the material surface in the combustion chamber and increases the hot surface temperature.
The preignition is more likely to occur.

Incidentally, if the knocking is merely caused by the properties of the fuel or the like, the knocking can be eliminated by, for example, retarding the ignition timing. However, in the case of knocking caused by pre-ignition, knocking does not stop even if ignition timing is retarded as described above or even if ignition is stopped, so the internal combustion engine runs away and breaks May occur.

Therefore, conventionally, for example, Japanese Utility Model Laid-Open Publication No.
Japanese Patent Application Laid-Open No. H11-163556 discloses an engine (internal combustion engine) that detects the occurrence of pre-ignition from the in-cylinder pressure during a compression stroke detected by an in-cylinder pressure sensor provided for each cylinder, and stops fuel supply to the cylinder in which the pre-ignition has occurred. Institutions) are disclosed.

[0005]

However, in the technology disclosed in the above-mentioned publication, it is necessary to incorporate an in-cylinder pressure sensor for each cylinder, so that the cost is unavoidable. In addition, when pre-ignition is detected, the fuel supply to the cylinder is immediately stopped, so that drivability may be significantly impaired. By the way, in the case of a mild case in which preignition does not occur continuously, there is a possibility that preignition will converge, for example, by narrowing the output slightly. However, since only the occurrence of preignition is uniquely detected and the fuel supply is stopped and controlled, it is difficult to perform control in consideration of drivability.

In general, a spark plug used for an internal combustion engine has a minimum necessary heat value in consideration of heat resistance (durability and preignition) during full load operation and self-cleaning property during normal operation. Is selected. However, in order to achieve high performance and low fuel consumption of the internal combustion engine, it is necessary to determine the specifications of the spark plug in consideration of combustion stability, exhaust gas, and fuel efficiency. It is difficult to determine the heat value.

[0007] The present invention has been made in view of such circumstances, and an object of the present invention is to easily and reliably prevent the occurrence of pre-ignition while effectively utilizing a knocking detection function provided in an internal combustion engine. An object of the present invention is to provide a control device for an internal combustion engine that can detect and prevent pre-ignition and effectively protect the internal combustion engine. Furthermore, the present invention effectively suppresses pre-ignition,
It is an object of the present invention to provide a control device for an internal combustion engine that can estimate a heat value margin of a spark plug to a minimum.

[0008]

In order to achieve the above object, a control apparatus for an internal combustion engine according to the present invention controls a combustion parameter for the internal combustion engine when knocking of the internal combustion engine is detected by knocking detection means. Knock suppression means for suppressing the knocking, despite the suppression of knocking by controlling the combustion parameters,
When the knocking continues for a predetermined period, the engine includes a pre-ignition determining means for detecting the occurrence of the pre-ignition in the internal combustion engine, and further, when the occurrence of the pre-ignition is detected by the pre-ignition determining means, Output control means for reducing the output of the cylinder in which the preignition has occurred.

Preferably, in the knocking suppression means, the knocking is suppressed by retarding the ignition timing of a cylinder in which knocking has been detected, and the output control means includes: The output of the cylinder is reduced by controlling the fuel injection amount or the intake air amount to decrease in the cylinder in which the preignition has occurred.

That is, when the knocking is detected by the knocking detecting means, the control device for the internal combustion engine according to the present invention suppresses the knocking by, for example, retarding the ignition timing, and in spite of the suppression control for the knocking. If the knocking continues for a predetermined period, it is determined that the cause of the knocking is pre-ignition, and the fuel injection amount or intake air amount for the cylinder in which the pre-ignition occurs is determined according to the determination result. The characteristic is that the ignition is suppressed by reducing the output of the motor.

According to a third aspect of the present invention, a control device for an internal combustion engine according to the present invention includes a preignition detecting means for detecting occurrence of preignition in the internal combustion engine based on detection information of knocking occurring in the internal combustion engine. The output reducing means for reducing the output of the cylinder in which the preignition is occurring in accordance with the duration of the preignition detected by the preignition detecting means, and the duration of the preignition is preset. An output stopping means for stopping the output of the cylinder in which the preignition has occurred when the determination period has elapsed is provided.

Preferably, as the output reducing means, the output is reduced by retarding the ignition timing or controlling the fuel injection amount or the intake air amount to decrease. In the output stopping means,
By stopping the fuel injection or the introduction of the intake air, the output control according to the degree of the pre-ignition is performed stepwise.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A control device for an internal combustion engine according to one embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 shows a schematic system configuration of an in-cylinder injection type internal combustion engine in which a control device according to this embodiment is incorporated. In FIG. 1, reference numeral 1 denotes an in-cylinder injection gasoline engine main body (hereinafter abbreviated as engine) for an automobile, reference numeral 2 denotes a fuel supply system, reference numeral 3 denotes an intake system, and reference numeral 4 denotes EGR (exhaust gas recirculation). System. Reference numeral 5 denotes an electronic control unit (ECU) that controls the entire system. The exhaust system including a three-way catalyst and a muffler is omitted.

This type of engine 1 is different from a general port injection type engine in that an electromagnetic fuel injection valve 12 is mounted on a cylinder head of the engine 1 together with a spark plug 11. The fuel is directly injected. On the top surface of the piston slidably held by the cylinder, a hemispherical cavity is located at a position where the fuel spray injected from the fuel injection valve 12 reaches the latter part of the compression stroke. Is formed.

Further, an intake port 13 is formed in the cylinder head in a substantially upright direction. This intake port 13
The intake air flow introduced into the combustion chamber from above generates a reverse tumble flow for promoting reliable combustion of the lean fuel in the combustion chamber. Further, an exhaust port 14 connected to the exhaust system is formed in a substantially horizontal direction, and a large-diameter EGR port 15 is branched and provided diagonally below the exhaust port 14. In the drawing, reference numeral 16 denotes a water temperature sensor for detecting the engine cooling water temperature Tw, and reference numeral 17 denotes a vane type crank angle sensor for outputting a crank angle signal SGT. Reference numeral 18 denotes a knocking sensor composed of a piezoelectric element.

On the other hand, the intake system 3 connected to the intake port 13 includes a surge tank 31 and a drive-by-wire type throttle body (DBW-
T / B) 32 and an intake pipe 3
3 and an air cleaner 34 connected through the air cleaner 3. An air flow sensor 3 for detecting an intake air amount Qa is provided near the air cleaner 34 in the intake pipe 33.
3a is provided. The throttle body 32 includes a butterfly type throttle valve 36 driven by a step motor 35 to open and close its flow path, and a throttle position sensor 37 for detecting the opening degree of the throttle valve 36 (throttle opening degree θTH). Also, an idle switch or the like for recognizing an idle state of the engine 1 by detecting a substantially fully closed state of the throttle valve 36 is incorporated.

The intake pipe 33 is provided with a bypass passage 38 for bypassing the throttle valve 36 and sucking air into the intake manifold (intake port 13). A bypass valve 39 is provided. This air bypass valve 3
Numeral 9 plays a role of opening the valve when the throttle valve 36 is out of order, for example, and enabling intake of a constant flow rate even when the throttle valve 36 is closed.

The EGR port 15 has a large diameter E.
A GR pipe 41 is connected, and a step motor type E
The EGR system 4 is connected upstream of the intake manifold via a GR valve 42. This EG
The R system 4 has a role of circulating a part of the exhaust gas from the engine 1 to the intake system of the engine 1, thereby lowering the combustion temperature in the combustion chamber of the engine 1 and reducing NOx emissions. . The amount of EGR gas circulated through the EGR system 4 is adjusted by controlling the opening of the EGR valve 42.

The fuel injection valve 12 has a fuel pipe 21
The fuel control device 22 is connected via the
Is supplied to the combustion chamber of the engine 1 at a predetermined fuel pressure. The amount of fuel injected through the fuel injection valve 12 is controlled by the fuel control device 22. More specifically, the amount of fuel injected is controlled by varying the valve opening time (fuel injection time Tinj) of the fuel injection valve 12. The ignition plug 11 is driven by an ignition coil 19, and its ignition timing Tign is adjusted under the control of the ECU 5.

An electronic control unit (ECU) 5 for overall control of the engine 1 includes an input / output device (not shown), a storage device (ROM, RAM, etc.) storing control programs and control maps, and a central processing unit. (CPU), a timer counter and the like. The ECU 5 inputs detection information from the various sensors described above, determines an ignition timing, an amount of EGR gas introduction, and the like, including a fuel injection mode and a fuel injection amount to be described later, and determines the fuel injection valve 12 and the ignition coil. 11, drive control of the EGR valve 42 and the like. In addition, a large number of switches and other sensors (not shown) are connected to the ECU 5, and various warning lights and devices are connected to the ECU 5.

The basic engine control in the in-cylinder injection type internal combustion engine (engine) 1 configured as described above will be briefly described. When the engine 1 is started, the engine 1 is in a cold state and the fuel vaporization rate is low. Since the fuel pressure is also low, the fuel injection control is first performed under the control of the ECU 5 so that the air-fuel ratio becomes relatively rich. When the engine 1 starts idling, the engine cooling water temperature Tw
Until the pressure rises to a predetermined value, fuel is injected in the same manner as at the time of the start to secure a rich air-fuel ratio. Thereafter, when a predetermined combustion cycle has elapsed and the O ₂ sensor has been activated, the air-fuel ratio feedback control according to the output of the O ₂ sensor is started under the control of the ECU 5, and harmful emissions from the engine 1 are started. Exhaust gas components are purified by a three-way catalyst.

When the warm-up of the engine 1 is completed, EC
U5 determines the control mode of fuel injection based on the target average effective pressure Pe obtained from the intake air amount Qa, the accelerator opening θTH, and the like, and the engine speed Ne, for example, by referring to a fuel injection control map. The fuel injection valve 12 is driven by determining the amount and the fuel injection timing. Further, in connection with this, opening / closing control of the slot valve 32 and the EGR valve 42 is performed. It should be noted that the fuel injection amount is determined by the valve opening time width Tinj of the fuel injection valve 12 as a matter of course.

To briefly explain each of the above fuel injection modes, in a low load region such as an idling operation or a low speed traveling, for example, a compression stroke injection mode in which fuel is injected in the latter half of the compression stroke to realize lean combustion is provided. Selected.
Particularly, in this compression stroke injection mode, the slot valve 32 is opened and the lean average air-fuel ratio (for example, 30 to 4) is set.
(About 0) is controlled. At this point, since the vaporization rate of the fuel has already risen, the fuel spray injected in the compression stroke collides with the top of the piston which moves to the top dead center, and the ignition plug follows the curved surface of the cavity. It is led around 11. As a result, at the time of the ignition, a mixture in the vicinity of the stoichiometric air-fuel ratio is formed in a layer around the spark plug 11, and even if the air-fuel ratio is lean as a whole, reliable ignition becomes possible, and lean combustion is realized. . In this control region, the EGR valve 42 is opened, and a large amount (for example, 30% or more) of EGR gas is introduced into the combustion chamber, so that the NOx is significantly reduced.

On the other hand, in a middle load region such as when the vehicle is traveling at a constant speed, an intake stroke injection mode in which fuel is injected in the first half of the intake stroke to achieve lean combustion according to the load condition and the engine speed Ne. The normal stoichiometric feedback control mode is selected. By the way, when the intake stroke injection mode is selected, the opening amount of the throttle valve 32 and the fuel injection amount from the fuel injection valve 12 are controlled so as to obtain a relatively lean air-fuel ratio (for example, about 20 to 23). You. In this case, the fuel spray is conveyed to the vicinity of the ignition plug 11 by the reverse tumble flow formed by the intake air flowing from the intake port 13, so that reliable ignition can be achieved even with a lean air-fuel ratio as a whole and stable lean combustion Is realized.

When executing the stoichiometric feedback control, the EG is controlled in accordance with the detection result of the O ₂ sensor.
By controlling the opening and closing of the R valve 42, feedback control of the air-fuel ratio is performed. In this case, the harmful exhaust gas component is purified by the three-way catalyst, and the EGR valve 42 is controlled to introduce an appropriate amount of EGR gas into the combustion chamber, thereby reducing NOx and the like generated as harmful exhaust gas.

On the other hand, in a high load region such as during rapid acceleration or high-speed running, the enrichment mode by open loop control is selected, and the accelerator opening θTH and the engine speed N
The fuel injection is controlled so that the air-fuel ratio becomes relatively rich according to e and the like. Note that during coasting operation during mid-high speed traveling,
For example, a fuel cut mode is set, and fuel injection into the combustion chamber is stopped. This fuel cut corresponds to the engine speed N
It is immediately stopped when e becomes lower than the return rotation speed or when the accelerator pedal is depressed.

In the in-cylinder injection type engine 1 which realizes lean combustion by the above-described combustion control, the control device according to the present invention is characterized in that the knocking sensor 18 detects the occurrence of knocking in the engine 1, It has a function to detect the occurrence of pre-ignition based on this knocking information, and furthermore, when the occurrence of pre-ignition is detected, suppresses the pre-ignition by controlling the output of the cylinder in which knocking (pre-ignition) has occurred. In addition, it has a function of preventing damage to the engine 1 due to pre-ignition.

That is, this function is realized as a part of the function provided in the ECU 5. As schematically shown in FIG. 2, the pre-ignition detection for detecting the occurrence of pre-ignition in accordance with the knocking information obtained from the knocking sensor 18 is performed. Means 51 and output control means 52 for reducing the output to the cylinder in which the preignition has occurred in accordance with the preignition detection result.

In particular, the preignition detecting means 51
Extracts a vibration frequency component unique to knocking by filtering an output from the knocking sensor 18,
Knocking detection means 53 for detecting the occurrence of knocking for each cylinder in accordance with the extracted component; and, when knocking is detected by the knocking detection means 53, combustion parameters for the cylinder in which knocking has occurred, Knocking control means 54 for suppressing knocking by retarding the ignition timing, and preignition determination for detecting knocking caused by preignition by monitoring the state of occurrence of knocking when knocking is suppressed by knocking control means 54 And means 55.

The knocking detecting means 53 and the knocking control means 54 for executing the ignition timing retard control utilize the control function for the conventional general knocking provided to eliminate the knocking caused by the fuel property or the like. This is achieved by: Further, the pre-ignition determination means 55 counts the number of continuous occurrences of knocking during knocking suppression as described later, and when the number of continuous occurrences exceeds a predetermined value, in other words, retards the ignition timing to suppress knocking. When the knocking continues to occur despite execution of the control, the knocking is detected as the occurrence of preignition.

That is, the pre-ignition detecting means 51
Is actively utilizing the functions of the knocking detection means 53 and the knocking control means 54 provided as a countermeasure against knocking, and controlling the combustion of the engine 1 to suppress knocking by retarding the ignition timing. Regardless, if the knocking is not eliminated, this is detected as a state in which fuel is ignited and burned, that is, preignition has occurred, irrespective of ignition of the air-fuel mixture by the spark plug 11.

When the occurrence of preignition is detected as described above, the detection information is given to the output control means 52, and the control of the combustion parameters for the engine 1 is performed to reduce the output. . Specifically, the output control means 52 reduces the amount of fuel injected through the fuel injection valve 12 or reduces the amount of intake air thereof, and furthermore, performs pre-ignition by, for example, retarding the ignition timing. Output control means 56 for reducing and controlling the output of each cylinder of the engine 1 and the cylinders of the engine 1. Further, there is provided an output stop control means 57 for forcibly controlling the output reduction control means 56 to stop the fuel injection and the introduction of the intake air itself and to stop the output of the cylinder.

The operation of the output reduction control means 56 and the output stop control means 57 is controlled by a pre-ignition number judging means 58 for counting the number of consecutive occurrences of pre-ignition detected by the pre-ignition detecting means 51. . In particular, the output stop control means 57 is operatively controlled based on the number of continuous detections of preignition detected by the preignition determination means 55 so as to increase the amount of output reduction by the output reduction control means 56 in accordance with the number of continuous detections. You. The output stop control means 57 is started when the number of consecutive detections exceeds a predetermined value, and forcibly stops the output of the engine via the output reduction control means 56. That is, the output of the engine 1 is stepwise reduced and controlled in accordance with the occurrence state of preignition, and when the occurrence of preignition is remarkable, the output itself of the engine 1 is finally stopped.

The pre-ignition judging means 55 shown in FIG. 2 judges the occurrence of pre-ignition from the number of continuous knocking detections, but the lapse of time during which knocking occurs continuously (knock continuation). The occurrence of the preignition may be detected by monitoring the period. Similarly, in the pre-ignition frequency determination means 58, the output reduction control means 56 and the output stop control means 57 are controlled not according to the number of continuous detections of pre-ignition but according to the duration of the occurrence state of pre-ignition. There may be.

Next, a series of control operations of the present apparatus configured as described above will be described. This control includes a pre-ignition detection process based on knocking information and an output control (pre-ignition suppression control) based on the detection result, as shown in FIG. The process starts by reading a knocking signal V _R obtained through the knocking sensor 18 every time [Step S1]. And knocking signal V
The level of _R is compared with a predetermined noise determination lower limit value V _NL and a noise determination upper limit value V _NH [Steps S2 and S2.
3] If the knocking signal V _R is smaller than the noise determination lower limit value V _NL, it is determined that there is a margin before the knocking occurrence condition, and the ignition timing is advanced (Step S).
4]. When the knocking signal V _R becomes larger than the noise judgment upper limit value V _NH For this, it was determined that knocking has occurred, and controls retarding the ignition timing [Step S5].

When the knocking signal V _R is between the noise determination lower limit value V _NL and the noise determination upper limit value V _NH , it is determined that the vehicle is in a normal operation state, and the above-described ignition timing control is performed. Not special. However, in this case, and when the above-described advance control of the ignition timing is performed, the control parameters n and m used for the pre-ignition determination described later are used.
Are reset to zero (0), respectively [Steps S6 and S
7], the processing procedure from step S1 described above is repeatedly executed.

When the knocking is detected and the ignition timing is retarded as described above [Step S3,
S5], and then increment a control parameter n for counting the number of consecutive knocking detections [Step S5].
8] It is determined whether or not the knocking consecutive detection number (control parameter n) has reached a pre-ignition determination value N set in advance [Step S9]. Then it until the knocking continuously detecting the number of times indicated by the control parameter n reaches the determination value N, perform the retard control of the ignition timing described above on the condition that the knock signal V _R becomes larger than the noise judgment upper limit value V _NH While counting the number of repetitions.

[0038] Incidentally in the period running repeatedly retard control of the ignition timing, when the disappearance of knocking from the knock signal V _R is detected, that the knocking by retarding control of the ignition timing is suppressed Because
It is determined that the knocking is normal due to fuel properties and the like. In this case, since the control parameter n is reset as described above, the number of consecutive knocking occurrences is counted again from this point.

When the number of consecutive knocking occurrences reaches the determination threshold N according to the control parameter n, knocking continues to occur despite the ignition timing retard control described above. It is determined that the knocking is caused by pre-ignition [Step S9]. Therefore, in this case, in order to suppress the pre-ignition, a process of reducing the output to the cylinder in which knocking has occurred, and eventually to the engine 1 is executed [Step S10]. This output reduction process
For example, reducing the amount of fuel injected into the cylinder,
Alternatively, it is performed by reducing the amount of intake air introduced into the cylinder. That is, the target engine output Pe, which is set based on the accelerator pedal depression amount and the engine speed Ne, which is the operating condition, is reduced by a predetermined amount, and the fuel injection amount and the introduced air amount are controlled to be reduced in order to suppress the pre-ignition. .

In this output reduction process, while the control parameter m for managing the duration of the preignition is incremented [Step S11], the number of continuous detections of the preignition (control parameter m) is set to a predetermined limit value M. It is repeatedly executed while determining whether or not it has reached [Step S12]. By this repetition processing, the number of continuous detections of preignition (duration)
, The degree of reduction of the target engine output Pe is gradually increased, and the engine output Pe is narrowed down.

When the number of continuous detections of preignition (duration) reaches the limit value M from the control parameter m, it is determined that the occurrence (continuation) of preignition beyond this will cause damage to the engine 1 and the engine output The device itself is controlled to stop [Step S13]. That is, the injection of fuel itself into the cylinder is stopped, or the introduction of an inhaler used for combustion is stopped.

When the pre-ignition is suppressed by the output reduction process, the knocking itself due to the pre-ignition is naturally eliminated, and the control parameters n and m are respectively reduced by the disappearance of the knock as described above. Reset [Step S6,
S7]. Therefore, in this case, the pre-ignition determination process based on the knocking information is repeatedly executed again.

As described above, according to the present apparatus which detects the occurrence of preignition and controls the output of the cylinder in accordance with the situation to suppress the preignition, damage to the engine 1 due to the continuation of preignition is eliminated. It can be prevented beforehand. In addition, since the occurrence of preignition is detected by effectively utilizing the knocking detection mechanism, a special detection mechanism such as an in-cylinder pressure sensor is not required, so that the configuration can be simplified and the detection accuracy can be improved. Can be raised enough.

Further, since the output reduction processing is executed according to the state of the preignition, especially the duration thereof, for example, in the case of a mild preignition, this can be quickly converged and the output can be reduced. Since the output is controlled to be stopped only when the preignition is continued despite the reduction control, there is no danger that the drivability is greatly deteriorated when the preignition is suppressed. In other words, in the case of mild play ignition, without compromising drivability,
Preignition can be effectively suppressed.

According to the present apparatus which can effectively suppress preignition as described above, the ignition plug 11
It is possible to estimate the heat value margin of the ignition plug 11 while minimizing the heat value margin of the ignition plug 11 while ensuring sufficient combustion characteristics at low and medium loads. And the like. In other words, in the past, from the viewpoint of pre-ignition and durability at full load, a high heat value spark plug was selected with a sufficient margin. It is possible to select a low heat value spark plug that emphasizes the combustion characteristics at the time of medium load.

Note that the present invention is not limited to the above embodiment. For example, when the occurrence of preignition is detected, the same output control may be simultaneously performed on all cylinders of the engine 1 as well as on the cylinder where the preignition has occurred. Further, it is of course possible to use ignition timing retard control together as output reduction control when suppressing preignition. In this case, control logic can be simplified by skipping steps S8, S9, and S10 shown in FIG. 3 and performing output stop control when the retard control amount reaches the limit value M. It is also possible to simultaneously execute the injection fuel amount reduction control and the air amount reduction control. Further, the present invention can be applied to not only a direct injection type engine but also an intake port injection type engine. In addition, the present invention can be variously modified and implemented without departing from the gist thereof.

[0047]

As described above, according to the present invention, the occurrence of pre-ignition is detected based on the information detected from the knocking sensor, and the output is reduced to the cylinder based on the detection result to reduce the pre-ignition. Because of suppression, it is possible to simply and effectively prevent engine damage. In addition, it is possible to select a low heat value ignition plug that emphasizes the combustion characteristics at low and medium loads, and to sufficiently exhibit the carbon purification function of the ignition plug.

In particular, knocking is suppressed by retarding the ignition timing of the cylinder in which knocking is detected, and furthermore, the pre-ignition is suppressed by reducing the output by reducing the fuel injection amount and intake air amount. Pre-ignition that continuously occurs under simple control can be reliably suppressed according to the degree of control while effectively utilizing the control.

Further, as described in claim 3, the output is gradually reduced in accordance with the duration of the preignition, and the output is stopped when a predetermined time has elapsed. Control, it is possible to suppress pre-ignition while suppressing drastic changes in engine output and prevent deterioration in drivability.If the pre-ignition still does not stop, the output is stopped, so the engine The effect of being able to reliably avoid the worst case of damage is achieved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part of a direct injection internal combustion engine to which the present invention is applied.

FIG. 2 is a functional block diagram showing a schematic configuration of a control device for an internal combustion engine according to one embodiment of the present invention.

FIG. 3 is a diagram showing a flow of a processing procedure showing an example of preignition detection processing and preignition suppression control according to the embodiment of the present invention. ,

[Explanation of symbols]

 REFERENCE SIGNS LIST 51 preignition detection means 52 output control means 53 knocking detection means 54 knocking control means 55 preignition determination means 56 output reduction control means 57 output stop control means 58 preignition number determination means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F02P 5/152 F02P 5/15 D 5/153

Claims (4)

[Claims] A knocking detecting means for detecting knocking occurring in the internal combustion engine; a knocking suppressing means for controlling a combustion parameter for the internal combustion engine when knocking is detected by the knocking detecting means to suppress the knocking; Despite the control of the combustion parameter by the knocking suppressing means, when the knocking continues for a predetermined period, a preignition determining means for detecting occurrence of preignition in the internal combustion engine, and a pre-ignition determining means for detecting the occurrence of the preignition in the internal combustion engine. An internal combustion engine control device, comprising: output control means for reducing the output of a cylinder in which preignition has occurred when the occurrence of ignition is detected. 2. The knocking suppression means for retarding ignition timing of a cylinder in which knocking is detected to suppress knocking, wherein the output control means reduces a fuel injection amount or an intake air amount. The control device for an internal combustion engine according to claim 1, wherein the control is performed to reduce the output of the cylinder. 3. A pre-ignition detecting means for detecting occurrence of pre-ignition in the internal combustion engine based on detection information of knocking occurring in the internal combustion engine, and according to a duration of the pre-ignition detected by the pre-ignition detecting means. Output reducing means for reducing the output of the cylinder in which the preignition has occurred,
An internal combustion engine control device, comprising: output stop means for stopping the output of a cylinder in which the preignition has occurred when the duration of the preignition exceeds a predetermined determination time. 4. The output reducing means reduces the output by retarding the ignition timing or controlling the fuel injection amount or the intake air amount to decrease, and the output stopping means controls the fuel injection. The control device for an internal combustion engine according to claim 3, wherein the intake air is stopped.