JP2007107458A - Control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine capable of appropriately determining whether or not abnormal combustion actually occurs during operation of the internal combustion engine and appropriately controlling the output of the internal combustion engine accordingly. .
A control device (1) detects output parameters (PCYL, NE) representing an output generated by combustion in an internal combustion engine (3), and temporarily stops the supply of fuel to the internal combustion engine (3) during operation of the internal combustion engine (3). Based on the output parameters PCYL and NE detected during the fuel cut, it is determined whether or not abnormal combustion that does not depend on the fuel occurs in the internal combustion engine 3 (steps 9, 12, and 5). , 13, 25, 28).
[Selection] Figure 2

Description

  The present invention relates to a control device for an internal combustion engine that determines the presence or absence of occurrence of abnormal combustion that does not depend on fuel and controls the internal combustion engine according to the determination result.

  Conventionally, as a control device for this type of internal combustion engine, for example, one disclosed in Patent Document 1 is known. In this internal combustion engine, a blow-by gas in the crankcase is recirculated to the intake pipe and burned in the combustion chamber, so that a PCV system communicating between the crankcase and the cylinder head cover and a blow-by gas chamber connected to the cylinder head cover are provided. And a PCV hose communicating the blow-by gas chamber and the intake pipe. The blow-by gas flows into the blow-by gas chamber from the crankcase through the PCV system and the cylinder head cover, and after the engine oil is separated in the blow-by gas chamber, it returns to the intake pipe through the PCV hose.

  In the internal combustion engine as described above, when the oil level of the engine oil in the blow-by gas chamber becomes high, this engine oil flows into the combustion chamber through the PCV hose and the intake pipe, and abnormal combustion may occur. . For this reason, in this conventional control device, when the oil level of the engine oil in the blow-by gas chamber is detected by the oil level sensor and the detected oil level is higher than a predetermined judgment value, It is determined that combustion may occur. Then, the throttle valve of the intake pipe is controlled to be fully closed, so that the internal combustion engine is forcibly stopped, thereby preventing the occurrence of abnormal combustion in advance.

  However, the above-described conventional control device only predicts the occurrence of abnormal combustion, and does not determine whether or not abnormal combustion actually occurs. Therefore, for example, when the oil level of the engine oil once exceeds the judgment value and then falls again due to a change in the operating state of the internal combustion engine, etc., although abnormal combustion does not actually occur, First, when the oil level rises once, it is determined that there is a possibility that abnormal combustion may occur, and accordingly, the internal combustion engine is stopped unnecessarily. Furthermore, an oil level sensor must be provided separately only for predicting the occurrence of abnormal combustion, and the manufacturing cost increases due to an increase in the number of parts.

  The present invention has been made to solve the above-described problems, and can appropriately determine whether or not abnormal combustion actually occurs during operation of the internal combustion engine. An object of the present invention is to provide a control device for an internal combustion engine that can appropriately control the output.

Japanese Utility Model Publication No.59-148410

  In order to achieve the above object, the control device 1 for an internal combustion engine 3 according to claim 1 is configured so that an in-cylinder pressure PCYL in an embodiment (hereinafter, the same in this section) represents an output generated by combustion in the internal combustion engine 3. Output parameter detecting means (in-cylinder pressure sensor 11, crank angle sensor 12, ECU 2) for detecting engine speed NE) and fuel for temporarily stopping the supply of fuel to internal combustion engine 3 during operation of internal combustion engine 3 Based on the output parameter detected when the fuel supply to the internal combustion engine 3 is stopped by the supply stop means (injector 4, ECU 2) and the fuel supply stop means, abnormal combustion that does not depend on fuel occurs in the internal combustion engine 3. And an abnormal combustion determination means (ECU 2, steps 9, 12, 5, 13, 25, 28) for determining whether or not it has occurred. To.

  According to this control device for an internal combustion engine, the output parameter representing the output generated by the combustion in the internal combustion engine is detected by the output parameter detection means. The fuel supply stop means temporarily stops the supply of fuel to the internal combustion engine during operation of the internal combustion engine (hereinafter, this fuel supply stop is referred to as “fuel cut”), and is detected during the fuel cut. Based on the output parameter, it is determined by the abnormal combustion determining means whether or not the abnormal combustion not depending on the fuel is occurring in the internal combustion engine.

  Normally, during the fuel cut, no fuel is burned in the internal combustion engine, so that no output of the internal combustion engine is generated. On the other hand, during the fuel cut, for example, the engine oil burns in the internal combustion engine, so that abnormal combustion not depending on the fuel may occur, and in this case, an output due to the abnormal combustion is generated. Therefore, as described above, based on the output parameter detected during the fuel cut, it is possible to appropriately determine that the abnormal combustion actually occurs when the output is generated. Therefore, for example, the output of the internal combustion engine can be appropriately controlled according to the determination result. In addition, since the fuel cut is normally performed when the internal combustion engine is decelerated, for example, to improve fuel efficiency, the fuel cut state is used to create a special driving state for determination. Without being able to make a determination, and a sufficient execution frequency of the determination can be secured.

  The invention according to claim 2 limits the output of the internal combustion engine 3 when the control device 1 for the internal combustion engine 3 according to claim 1 determines that abnormal combustion has occurred by the abnormal combustion determination means. Further, output limiting means (throttle valve mechanism 6, ECU 2, step 14) is further provided.

  According to this configuration, when it is determined that abnormal combustion has occurred during the fuel cut, the output of the internal combustion engine is limited by the output limiting means, so that the internal combustion engine due to abnormal combustion that is particularly problematic during the fuel cut Can be prevented immediately and reliably. In addition, since the limitation of the output of the internal combustion engine can be performed appropriately to a minimum only when abnormal combustion actually occurs, unlike the conventional case where the occurrence of abnormal combustion is predicted, the internal combustion engine is unnecessary. Stopping can be prevented.

  According to a third aspect of the present invention, in the control device 1 for the internal combustion engine 3 according to the first or second aspect, the output parameter detecting means detects the pressure in the cylinder C of the internal combustion engine 3 (in-cylinder pressure PCYL) as the output parameter. In-cylinder pressure sensor 11 is provided.

  According to this configuration, since the pressure in the cylinder having a close correlation with the output is used as the output parameter, it is possible to accurately determine whether or not abnormal combustion has occurred by the abnormal combustion determination means described above. it can. In addition, when the in-cylinder pressure sensor is already provided, it is not necessary to newly provide a part for determining the occurrence of abnormal combustion, and therefore the manufacturing cost can be reduced by reducing the number of parts.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 schematically shows a control device 1 according to the present embodiment together with an internal combustion engine 3 to which the control device 1 is applied. An internal combustion engine (hereinafter referred to as “engine”) 3 is, for example, a diesel engine mounted on a vehicle (not shown), and its crankshaft 3 a is attached to a wheel via a manual transmission (not shown). It is connected.

  A fuel injection valve (hereinafter referred to as “injector”) 4 (fuel supply stop means) is attached to the cylinder head 3 b of the engine 3 so as to face the combustion chamber. The fuel injection amount of the injector 4 is controlled by a drive signal from the ECU 2 described later of the control device 1. Further, an in-cylinder pressure sensor 11 (output parameter detection means) is integrally attached to the injector 4. The in-cylinder pressure sensor 11 is composed of a piezoelectric element, and outputs a detection signal indicating the amount of change in pressure in the cylinder C of the engine 3 to the ECU 2. The ECU 2 integrates this detection signal to calculate the pressure in the cylinder C, and obtains the maximum value of the pressure in the cylinder C for each combustion cycle as the in-cylinder pressure PCYL.

  A magnet rotor 12a is attached to the crankshaft 3a, and a crank angle sensor 12 (output parameter detection means) is configured by the magnet rotor 12a and the MRE pickup 12b. The crank angle sensor 12 outputs a CRK signal and a TDC signal, both of which are pulse signals, to the ECU 2 as the crankshaft 3a rotates. The CRK signal is output every predetermined crank angle (for example, 30 °). The ECU 2 obtains the rotational speed NE (hereinafter referred to as “engine rotational speed”) NE of the engine 3 based on the CRK signal. The TDC signal is a signal indicating that the piston P of the cylinder C is at a predetermined crank angle position near the TDC (top dead center) at the start of the intake stroke.

  The engine 3 is provided with a throttle valve mechanism 6 (output limiting means). The throttle valve mechanism 6 includes a throttle valve 6a and an actuator 6b that opens and closes the throttle valve 6a. The throttle valve 6a is rotatably provided in the middle of the intake pipe 5, and the amount of intake air changes as the opening degree changes. The actuator 6b is a combination of a motor connected to the ECU 2 and a gear mechanism (both not shown). When the actuator 6b is driven by a drive signal from the ECU 2, the opening of the throttle valve 6a (hereinafter referred to as "throttle valve"). TH) is changed.

  The engine 3 is provided with a PCV system 7. The PCV system 7 circulates the blow-by gas in the crankcase 3 c of the engine 3 to the intake pipe 5 as appropriate, and has a blow-by gas passage 8 and a gas-liquid separation chamber 9.

  One end of the blow-by gas passage 8 is connected to the cylinder head cover 3 d of the engine 3, and the other end is connected to the downstream side of the throttle valve 6 a of the intake pipe 5. The gas-liquid separation chamber 9 is for separating engine oil from blow-by gas, and is provided in the cylinder head cover 3d. The engine 3 is formed with a breather passage (both not shown) extending from the cylinder head 3b to the cylinder block, and the breather passage opens into the crankcase 3c. The blow-by gas flows from the crankcase 3 c into the cylinder head cover 3 d through the breather passage, and after the engine oil is separated in the gas-liquid separation chamber 9, it returns to the intake pipe 5 through the blow-by gas passage 8. To do. The engine oil in the gas-liquid separation chamber 9 is appropriately returned to an oil pan (not shown) provided at the lower end of the crankcase 3c via a return passage (not shown).

  An accelerator opening sensor 13 and a shift position sensor 14 are connected to the ECU 2. The accelerator opening sensor 13 detects an operation amount (hereinafter referred to as “accelerator opening”) AP of an accelerator pedal (not shown), and outputs a detection signal to the ECU 2. The shift position of the shift lever (not shown) operated by the driver of the shift position sensor 14 is any of 1st to 6th (first speed to sixth speed), R (reverse), and N (neutral). Is detected, and a POSI signal representing it is output to the ECU 2.

  The ECU 2 is composed of a microcomputer including an I / O interface, CPU, RAM, ROM, and the like. The ECU 2 determines the operating state of the engine 3 according to the detection signals from the various sensors 11 to 14 described above, and the fuel of the injector 4 according to the control program stored in the ROM according to the determined operating state. Engine control including injection quantity control is executed. In the present embodiment, the ECU 2 corresponds to output parameter detection means, fuel supply stop means, abnormal combustion determination means, and output restriction means.

  The fuel injection amount is basically calculated by searching a map (not shown) according to the engine speed NE and the accelerator pedal opening AP. Further, during deceleration operation of the vehicle, for example, when the accelerator opening AP is substantially equal to a predetermined opening (for example, 0 °) and the engine speed NE is higher than the predetermined speed (for example, 1000 rpm), the fuel injection amount is a value. By setting it to 0, a deceleration fuel cut (hereinafter referred to as “deceleration F / C”) for stopping the fuel supply is executed.

  Further, when the vehicle is running or stopped, when the accelerator opening AP is substantially 0 and the shift position (POSI) of the shift lever is N (neutral), the engine speed NE is set to a predetermined idle speed NEIDLE ( For example, the fuel injection amount is controlled to be 800 rpm (hereinafter, such control is referred to as “idle F / B control”). Further, during the idle F / B control, when the engine speed NE exceeds the idle speed NEIDLE, when the fuel injection amount is repeatedly reduced in order to converge the engine speed NE to the idle speed NEIDLE. Finally, a fuel cut state (hereinafter referred to as “idle time F / C”) is reached in which the fuel supply is stopped.

  Further, in the abnormal combustion determination process described below, the ECU 2 causes the engine oil to flow into the intake pipe 5 through the blow-by gas passage 8 and the like, and burns in the engine 3 so that the abnormal combustion is not caused by the fuel supply. Whether or not has occurred is determined.

  FIG. 2 shows an abnormal combustion determination process according to the first embodiment of the present invention. This process is executed in synchronization with the generation of the TDC signal. First, in step 1 (illustrated as “S1”, the same applies hereinafter), it is determined whether or not the in-cylinder pressure sensor normal flag F_SCOK is “1”. This in-cylinder pressure sensor normal flag F_SCOK is set to “1” when it is determined that the in-cylinder pressure sensor 11 is normal in an abnormality determination process (not shown) of the in-cylinder pressure sensor 11. In this abnormality determination process, for example, when the in-cylinder pressure PCYL detected during the intake stroke during operation of the engine 3 is within a predetermined range, it is determined that the in-cylinder pressure sensor 11 is normal, and otherwise Is determined to be abnormal.

  If the answer to step 1 is NO and the in-cylinder pressure sensor 11 is abnormal, the process is terminated. On the other hand, if the answer to step 1 is YES and the in-cylinder pressure sensor 11 is normal, it is determined whether or not the engine 3 is in the deceleration F / C described above (step 2).

  If the answer to step 2 is NO and the deceleration F / C is not in progress, the following steps 3 to 6 are executed without performing the abnormal combustion determination, and this process is terminated. First, in steps 3 and 4, the timer value TMF / C of the up-counting type F / C timer and the integrated value SDPCYL of the in-cylinder pressure deviation are reset to a value of 0, respectively. Next, the abnormal combustion flag F_CNG is reset to “0” (step 5), and normal control of the throttle valve 6a is executed (step 6). During normal control of the throttle valve 6a, the throttle valve 6a is controlled to a fully open state, for example.

  On the other hand, if the answer to step 2 is YES and the vehicle is decelerating F / C, it is determined whether or not the abnormal combustion flag F_CNG is “1” (step 7). The abnormal combustion flag F_CNG is set to “1” when it is determined that abnormal combustion has occurred during the current deceleration F / C, as will be described later.

  When this answer is NO, that is, when it is not determined that abnormal combustion has occurred during the current deceleration F / C, the timer value TMF / C of the F / C timer reset in step 3 is It is determined whether or not a predetermined time TMREF (for example, 1.0 sec) or longer (step 8).

  When the answer to step 8 is NO, that is, when the predetermined time TMREF has not elapsed after the start of the deceleration F / C, it is determined whether or not the in-cylinder pressure PCYL is greater than a predetermined first determination value PCYLJUD. (Step 9). The first determination value PCYLJUD is set to, for example, a predetermined maximum value of the in-cylinder pressure that should be obtained when the crankshaft 3a is rotated without performing combustion in the engine 3 (hereinafter referred to as “non-combustion in-cylinder pressure”). Has been.

  If the answer to step 9 is NO and the in-cylinder pressure PCYL is equal to or less than the first determination value PCYLJUD, that is, the non-combustion in-cylinder pressure, step 6 is executed. On the other hand, if the answer to step 9 is YES and PCYL> PCYLJUD, the in-cylinder pressure deviation DPCYL is calculated by subtracting the first determination value PCYLJUD from the in-cylinder pressure PCYL (step 10). Next, the current integrated value SDPCYL is calculated by adding the calculated in-cylinder pressure deviation DPCYL to the integrated value SDPCYL of the in-cylinder pressure deviation obtained so far (step 11).

  Next, it is determined whether or not the calculated integrated value SDPCYL is larger than a predetermined second determination value SDPCYLJUD (step 12). As is apparent from the calculation method described above, the integrated value SDPCYL is calculated as a value reflecting both the deviation between the in-cylinder pressure PCYL and the non-combustion in-cylinder pressure and the number of times that the in-cylinder pressure PCYL exceeds the in-cylinder pressure during non-combustion. Is done. Therefore, the larger the value, the higher the possibility that abnormal combustion has occurred. Therefore, if the answer to step 12 is NO and the integrated value SDPCYL ≦ second determination value SDPCYLJUD, it is determined that no abnormal combustion has occurred, and the routine proceeds to step 6 where normal control of the throttle valve 6a is executed.

  On the other hand, if the answer to step 12 is YES and SDPCYL> SDPCYLJUD, it is determined that abnormal combustion has occurred, and the abnormal combustion flag F_CNG is set to “1” (step 13). Next, the throttle valve 6a is controlled to be fully closed (step 14), and this process is terminated. Thus, by stopping the supply of intake air to the combustion chamber, abnormal combustion is forcibly stopped, and the output of the engine 3 is controlled to a value of zero.

  If the abnormal combustion flag F_CNG is set to “1” in step 13, the answer to step 7 is YES until the deceleration F / C is completed. 14 is executed, and the fully closed control of the throttle valve 6a is continued.

  On the other hand, if the answer to step 8 is YES (TMF / C ≧ TMREF) and it is determined that abnormal combustion has not occurred after the start of deceleration F / C, and the predetermined time TMREF has elapsed, the step 4 and subsequent steps are executed. As described above, the abnormal combustion determination in steps 9 to 12 is terminated when the predetermined time TMREF has elapsed after the start of the deceleration F / C.

  As described above, according to the present embodiment, the occurrence of abnormal combustion is determined using the in-cylinder pressure PCYL detected during the deceleration F / C as an output parameter. . In addition, since the presence or absence of actual occurrence of abnormal combustion can be determined, unlike the conventional case where the occurrence of abnormal combustion is predicted, unnecessary stop of the engine 3 can be prevented. In addition, the occurrence of abnormal combustion is determined during deceleration F / C, and the output is controlled to a value of 0 when it is determined that abnormal combustion has occurred. It can be surely prevented. Further, it is possible to make a determination without using the deceleration F / C state without creating an operation state for the determination, and it is possible to sufficiently ensure the execution frequency of the determination. Furthermore, since the existing in-cylinder pressure sensor 11 is used for the abnormal combustion determination, it is not necessary to newly provide parts, and therefore determination can be performed without increasing the cost.

  As described above, the integrated value SDPCYL reflects both the deviation between the in-cylinder pressure PCYL and the non-combustion in-cylinder pressure and the number of times that the in-cylinder pressure PCYL exceeds the in-cylinder pressure during non-combustion. By performing the abnormal combustion determination based on the comparison result between the integrated value SDPCYL and the second determination value SDPCYLJUD, the reliability of the determination can be improved. Further, the abnormal combustion determination is terminated when a predetermined time TMREF has elapsed after the start of the deceleration F / C. As a result, when the situation where the in-cylinder pressure PCYL exceeds the first determination value PCYLJUD occurs sporadically, abnormal combustion occurs due to the integrated value SDPCYL calculated over a long period of time exceeding the second determination value SDPCYLJUD. The situation of misjudging that it is present can be avoided.

  Next, the abnormal combustion determination process according to the second embodiment of the present invention will be described with reference to FIG. As the output parameter, the in-cylinder pressure PCYL is used in the first embodiment described above, whereas the engine speed NE is used in the present embodiment. In FIG. 3, the same step numbers are assigned to the portions of the same execution contents as the processing of FIG. 2 according to the first embodiment. Hereinafter, the description will focus on the portion of execution content different from the processing of FIG. This process is executed every predetermined time.

  In this process, first, without executing Step 1, in Steps 19 and 20, it is determined whether or not the accelerator opening AP is substantially 0, and the shift position (POSI) of the shift lever is N (neutral). Each is determined whether or not there is. When any of these answers is NO, in steps 21 and 22, the timer value TMF / CN of the up-counting F / CN timer and the accumulated value SDNE of the rotational speed deviation are reset to the value 0, respectively, Perform steps 5 and 6. Thus, when the shift position of the shift lever is not N, that is, when the crankshaft 3a and the wheels are connected to each other, the abnormal combustion determination is not executed. This is because in this process, abnormal combustion determination is performed using the engine speed NE as an output parameter of the engine 3, so that erroneous determination is prevented by eliminating the influence of the wheel rotation on the engine speed NE. It is.

  On the other hand, when both of the answers to steps 19 and 20 are YES, that is, when the above-described idle F / B control is being executed while the vehicle is running or stopped, the above-described idling F / C is being performed. It is determined whether or not there is (step 23). When this answer is NO, the above steps 21 and after are executed.

  On the other hand, when the answer to step 23 is YES and the idling F / C is being performed during the idling F / B control, the step 7 is executed. If the answer to step 7 is NO (F_CNG = 0) and it is not determined that abnormal combustion has occurred during the current idle F / B control, the timer value of the F / CN timer reset in step 21 above It is determined whether TMF / CN is equal to or longer than the first predetermined time TM1 (for example, 2 sec) and smaller than the second predetermined time TM2 (for example, 3 sec) (step 24).

  When the answer to step 24 is NO, that is, when the first predetermined time TM1 has not elapsed after the idling F / C is executed during the idle F / B control, or the second predetermined time TM2 is When the time has elapsed, step 22 and subsequent steps are executed. As described above, the reason why the abnormal combustion determination is performed after the first predetermined time TM1 has elapsed is that the determination is performed after the engine speed NE, which decreases due to the idling F / C, is stabilized. Further, when it is determined that the abnormal combustion has not occurred and the second predetermined time TM2 has elapsed, the abnormal combustion determination is terminated at step 24 as in the first embodiment.

  On the other hand, when the answer to step 24 is YES and the first predetermined time TM1 has elapsed and the second predetermined time TM2 has not elapsed after the idling F / C is executed during the idle F / B control, It is determined whether or not the engine speed NE is higher than a predetermined third determination value NEJUD (step 25). The third determination value NEJUD is set to a predetermined value larger than the idle speed NEIDLE, for example, 1500 rpm.

  When the answer to step 25 is NO and the engine speed NE is equal to or less than the third determination value NEJUD, step 6 is executed. On the other hand, when the answer to step 25 is YES and the engine speed NE is higher than the third determination value NEJUD, the rotation speed deviation DNE is calculated by subtracting the third determination value NEJUD from the engine speed NE (step) 26). Next, the current integrated value SDNE is calculated by adding the calculated rotational speed deviation DNE to the integrated value SDNE of the rotational speed deviations obtained so far (step 27). Next, it is determined whether or not the calculated integrated value SDNE is greater than a predetermined fourth determination value SDNEJUD (step 28).

  When the engine speed NE exceeds the third determination value NEJUD (step 25: YES), the connection with the wheel side is released during the feedback control of the engine speed NE to the idle speed NEIDLE, and the fuel Although NE is stopped, NE still exceeds the third determination value NEJUD larger than NEIDLE, and the cause is likely to be abnormal combustion. Further, as apparent from the calculation method described above, the integrated value SDNE reflects both the deviation between the engine speed NE and the third determination value NEJUD, and the number of times the engine speed NE exceeds the third determination value NEJUD. Is calculated as Therefore, the larger the value, the higher the possibility that abnormal combustion has occurred.

  Therefore, if the answer to step 28 is NO and the integrated value SDNE ≦ the fourth determination value SDNEJUD, it is determined that abnormal combustion has not occurred, and the step 6 is executed. On the other hand, if the answer to step 28 is YES and SDNE> SDNEJUD, it is determined that abnormal combustion has occurred, and the abnormal combustion flag F_CNG is set to “1” as in the first embodiment described above (step 13). In addition, the throttle valve 6a is controlled to be fully closed (step 14), whereby the abnormal combustion is forcibly stopped and the output of the engine 3 is controlled to a value of zero.

  As described above, according to the present embodiment, the occurrence of abnormal combustion is determined using the engine speed NE detected during idle F / B control and during idle F / C as an output parameter. Can be performed appropriately. Further, as in the first embodiment, the presence or absence of actual occurrence of abnormal combustion can be determined, and the occurrence of abnormal combustion is determined during idling F / C. When such determination is made, the output is set to a value of 0. Control. Further, the abnormal combustion determination is performed using the idling F / C state, and the existing crank angle sensor 12 is used for the abnormal combustion determination. As described above, the effects of the first embodiment can be obtained similarly.

  Moreover, since the abnormal combustion determination is performed based on the comparison result between the integrated value SDNE calculated as described above and the fourth determination value SDNEJUD, the reliability of the determination can be improved. Further, as in the first embodiment, the abnormal combustion determination is terminated when the second predetermined time TM2 has elapsed after the start of the idling F / C. Thereby, when the situation where the engine speed NE exceeds the third determination value NEJUD occurs sporadically, the integrated value SDNE calculated over a long period of time exceeds the fourth determination value SDNEJUD, and abnormal combustion occurs. It is possible to avoid the situation of misjudging that it is.

  In addition, this invention can be implemented in various aspects, without being limited to the described embodiment. For example, in this embodiment, the in-cylinder pressure PCYL or the engine speed NE is used as the output parameter. However, the present invention is not limited to this as long as it is a parameter representing the output of the engine 3, and other appropriate parameters may be used. For example, the temperature in the cylinder C or the temperature of the exhaust gas may be used.

  In the present embodiment, when it is determined that abnormal combustion has occurred, the output of the engine 3 is controlled to a value of 0, but the output may be reduced. Further, in the present embodiment, the output is limited by the limiting means by controlling the throttle valve opening TH. However, the present invention is not limited to this. For example, the intake valve 20 of the engine 3 is controlled by other appropriate methods. This may be done by limiting the amount of intake air by controlling the maximum head (see FIG. 1).

  In the first embodiment, the non-combustion in-cylinder pressure used as the first determination value PCYLJUD to be compared with the in-cylinder pressure PCYL may be set as follows. For example, since the non-combustion in-cylinder pressure has a characteristic of changing according to the engine speed NE, the relationship between the non-combustion in-cylinder pressure and the engine speed NE is mapped from experimental results and searched from this map. The non-combustion in-cylinder pressure may be set as the first determination value PCYLJUD. In this case, since the first determination value PCYLJUD can be appropriately set according to the change characteristic of the non-combustion in-cylinder pressure with respect to the engine speed NE, the accuracy of the abnormal combustion determination can be improved. In addition, it is possible to appropriately change the detailed configuration within the scope of the gist of the present invention.

It is a figure which shows roughly the control apparatus by this embodiment with the internal combustion engine to which this is applied. It is a flowchart which shows the determination process of the abnormal combustion by 1st Embodiment. It is a flowchart which shows the determination process of the abnormal combustion by 2nd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control apparatus 2 ECU (Output parameter detection means, fuel supply stop means, abnormal combustion determination means,
Output limiting means)
3 Engine 4 Injector (Fuel supply stop means)
6 Throttle valve mechanism (output limiting means)
C cylinder 11 cylinder pressure sensor (output parameter detection means)
12 Crank angle sensor (output parameter detection means)
PCYL In-cylinder pressure (output parameter, cylinder pressure)
NE Engine speed (output parameter)

Claims (3)

Output parameter detecting means for detecting an output parameter representing an output generated by combustion in the internal combustion engine;
Fuel supply stopping means for temporarily stopping the supply of fuel to the internal combustion engine during operation of the internal combustion engine;
Based on the output parameter detected when the fuel supply to the internal combustion engine is stopped by the fuel supply stop means, it is determined whether or not abnormal combustion not using fuel has occurred in the internal combustion engine. Abnormal combustion determination means;
A control device for an internal combustion engine, comprising:   2. The internal combustion engine according to claim 1, further comprising an output limiting unit that limits an output of the internal combustion engine when the abnormal combustion determination unit determines that the abnormal combustion has occurred. Control device.   The control apparatus for an internal combustion engine according to claim 1 or 2, wherein the output parameter detection means is an in-cylinder pressure sensor that detects a pressure in a cylinder of the internal combustion engine as the output parameter.

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