JP2010071107A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine more accurately controlling ignition timing by using cylinder pressure. <P>SOLUTION: This device includes: a combustion rate calculation part 40 calculating total heat release quantity THA released during a period from combustion start to combustion completion in each combustion cycle, heat release quantity HA released during a period from the combustion start to a predetermined point of time, and combustion rate MFB of the heat release quantity HA to total heat release quantity THA based on cylinder pressure detected by a cylinder pressure sensor 15; an ignition timing control part 30 controlling ignition timing to make the combustion rate MFBθ at a predetermined point of time follow a target value; and a total heat release quantity correction part 50 correcting total heat release quantity to be used in calculation based on comparison of the total heat release quantity THA and reference value SHA set to each operation condition in relation to the total heat release quantity in calculation of the combustion rate MFBθ. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an internal combustion engine control device, and more particularly to an internal combustion engine control device that controls ignition timing based on in-cylinder pressure.

  Various ignition timing control for an internal combustion engine has been proposed, but Patent Documents 1 and 2 disclose a technique for controlling the ignition timing based on the in-cylinder pressure of the internal combustion engine.

  Patent Document 1 detects the in-cylinder pressure of an internal combustion engine, calculates a state quantity that reflects the combustion state at each time point in the combustion chamber based on the detected value, and determines torque fluctuation or misfire based on this state quantity. A technique is disclosed in which at least one of the ratio determinations is performed, and the internal combustion engine is controlled by changing the ignition timing based on the determination result.

  Further, Patent Document 2 detects the in-cylinder pressure in the combustion chamber in each combustion cycle of the internal combustion engine, and at each time point with respect to the total heat generation amount generated from the start of combustion to the end of combustion based on the in-cylinder pressure. A technique is disclosed in which a combustion rate (MFB) composed of a rate of heat generation is calculated, and operating conditions such as ignition timing are changed so that the combustion rate at a predetermined crank angle becomes a target value.

JP 2007-285194 A JP 2006-220139 A

By the way, in the technique disclosed in Patent Document 2, when the in-cylinder pressure detected by the in-cylinder pressure detecting means is P, the in-cylinder volume when the in-cylinder pressure P is detected is V, and the specific heat ratio is κ. The product value P · V ^κ (hereinafter referred to as “PV ^κ ” as appropriate) of the in-cylinder pressure P and the value V ^{κ obtained} by raising the in-cylinder volume V by a specific heat ratio (predetermined index) κ is an internal combustion engine. The ratio (MFB) of the heat generation amount at each crank angle θ with respect to the total heat generation amount is calculated by using the reflection of the heat generation amount Q in the combustion chamber. In the following equation, START indicates PV ^κ near the start of combustion, and END indicates PV ^κ near the end of combustion.

  Here, FIG. 9A is a graph showing an example of a change in the amount of heat generated from the start of combustion to the end of combustion in one combustion cycle of the combustion chamber, and FIG. It is a graph which shows an example of change of combustion rate MFB computed using data of A).

  The graph (1) in FIG. 9A is data at the time of normal combustion, and the graph (2) is data at the time of combustion with a misfire. As can be seen from FIG. 9A, the heat generation amount Q is clearly different.

  On the other hand, the graph (1) in FIG. 9B is the combustion rate MFB at the time of normal combustion, and the graph (2) is the combustion rate MFB at the time of misfiring combustion. As can be seen from FIG. 9B, when the combustion ratio MFB is compared between normal combustion and misfire combustion, there is no significant difference between the two.

In the ignition timing control based on the in-cylinder pressure, for example, the deviation between the combustion ratio MFB _θ and the target combustion ratio rMFB at the crank angle θ of 8 ° after the top dead center (TDC) is calculated, and this deviation is compensated. The ignition timing is controlled by proportional integral control.

However, when the difference between the combustion ratio MFB _θ and the target combustion ratio rMFB is compared between normal combustion and misfire combustion, there is no difference between the two, as can be seen from FIG. That is, there is a problem that precise ignition timing control is difficult because the ignition timing is operated with the same operation amount during normal combustion and misfiring combustion.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a control device for an internal combustion engine that can control ignition timing more precisely by using in-cylinder pressure.

  The control apparatus for an internal combustion engine according to the present invention includes a cylinder pressure detection means for detecting a cylinder pressure in a combustion chamber of the internal combustion engine, and a combustion from the start of combustion in each combustion cycle based on the cylinder pressure detected by the cylinder pressure detection means. Combustion rate calculation to calculate the total heat generation amount generated until the end, the heat generation amount generated from the start of combustion to the predetermined time point, and the combustion ratio that is the ratio of the heat generation amount to the total heat generation amount Means, an ignition timing control means for controlling the ignition timing so that the combustion ratio calculated by the combustion ratio calculation means at a predetermined time follows the target value, and when calculating the combustion ratio, the total heat generation amount, A total heat generation amount correcting means for correcting the total heat generation amount used for calculation is provided on the basis of a comparison with a standard value set for each operation condition with respect to the total heat generation amount.

  In the above configuration, the total heat generation amount correcting means adopts a configuration in which, when the total heat generation amount is not in a predetermined relationship with the standard value, the combustion ratio is calculated using the standard value instead of the total heat generation amount. it can.

  In the above configuration, the combustion rate calculating means includes a standard value correcting means for correcting a standard value based on an average value of a plurality of total heat generation amounts calculated for one combustion chamber. Further, the standard value correcting means corrects the standard value set for each of the plurality of combustion chambers based on one of the plurality of average values of the total heat generation amounts calculated for the plurality of combustion chambers. Configuration can be adopted.

  According to the present invention, the ignition timing control of the internal combustion engine using the in-cylinder pressure can be executed more precisely.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a configuration diagram illustrating an example of an engine (internal combustion engine) to which a control device according to an embodiment of the present invention is applied.

  The engine 1 generates power by burning a fuel / air mixture in a combustion chamber 3 formed in a cylinder block 2 and reciprocating a piston 4 in the combustion chamber 3. The engine 1 is preferably configured as a multi-cylinder engine, and the engine 1 of the present embodiment is configured as a four-cylinder engine, for example.

  An intake port of each combustion chamber 3 is connected to an intake pipe (intake manifold) 5, and an exhaust port of each combustion chamber 3 is connected to an exhaust pipe (exhaust manifold) 6. In addition, an intake valve Vi and an exhaust valve Ve are provided for each combustion chamber 3 in the cylinder head of the engine 1. Each intake valve Vi opens and closes a corresponding intake port, and each exhaust valve Ve opens and closes a corresponding exhaust port. Each intake valve Vi and each exhaust valve Ve are operated by, for example, a valve operating mechanism (not shown) having a variable valve timing function. Further, the engine 1 has a number of spark plugs 7 corresponding to the number of cylinders, and the spark plugs 7 are disposed in the cylinder heads so as to face the corresponding combustion chambers 3.

  The intake pipe 5 is connected to a surge tank 8 as shown in FIG. An air supply line is connected to the surge tank 8, and the air supply line is connected to an air intake port (not shown) via an air cleaner 9. A throttle valve (in this embodiment, an electronically controlled throttle valve) 10 and an air flow meter 21 are incorporated in the air supply line (between the surge tank 8 and the air cleaner 9). On the other hand, as shown in FIG. 1, a front-stage catalyst device 11 a including a three-way catalyst and a rear-stage catalyst device 11 b including a NOx storage reduction catalyst are connected to the exhaust pipe 6.

  Further, the engine 1 has a plurality of injectors 12, and each injector 12 is disposed so as to face the inside of the corresponding intake pipe 5 (inside the intake port) as shown in FIG. 1. Each injector 12 injects fuel such as gasoline into each intake pipe 5. Although the engine 1 of the present embodiment is described as a so-called port injection type gasoline engine, the present invention is not limited to this, and it goes without saying that the present invention can be applied to a so-called direct injection type internal combustion engine. Needless to say, the present invention can be applied not only to a gasoline engine but also to a diesel engine.

Each of the spark plugs 7, the throttle valve 10, the injectors 12, the valve operating mechanism and the like described above are electrically connected to an ECU 20 that functions as a control device for the engine 1. The ECU 20 includes a CPU, a ROM, a RAM, an input / output port, an A / D and D / A converter, and a storage device, all not shown. As shown in FIG. 1, various sensors such as a crank angle sensor 14, an air flow meter 21, and an air-fuel ratio sensor (O ₂ sensor) 16 provided in the exhaust pipe 6 are electrically connected to the ECU 20. The ECU 20 uses the various maps stored in the storage device and also obtains the desired output based on the detection values of the various sensors and the like, so that each spark plug 7, the throttle valve 10, each injector 12, Control the mechanism.

  Further, the engine 1 has in-cylinder pressure sensors (in-cylinder pressure detecting means) 15 including a semiconductor element, a piezoelectric element, an optical fiber detection element, or the like, corresponding to the number of cylinders. Each in-cylinder pressure sensor 15 is disposed on the cylinder head so that the pressure receiving surface faces the corresponding combustion chamber 3, and is electrically connected to the ECU 20. Each in-cylinder pressure sensor 15 detects the in-cylinder pressure (relative pressure) in the corresponding combustion chamber 3 and gives a signal indicating the detected value to the ECU 20. The detection value of each in-cylinder pressure sensor 15 is sequentially given to the ECU 20 every predetermined time (predetermined crank angle), corrected to an absolute pressure, and stored and held in a predetermined storage area (buffer) of the ECU 20 by a predetermined amount. .

  In the engine 1 configured as described above, basically, the air-fuel ratio of the fuel and air in each combustion chamber 3 during operation is set to the stoichiometric air-fuel ratio (about 14.7). That is, the air-fuel ratio sensor 16 in the exhaust pipe 6 outputs a voltage corresponding to the oxygen concentration in the exhaust gas flowing through the exhaust pipe 6, and the ECU 20 takes into account the response delay of the air-fuel ratio sensor 16 and the like. Thus, the rich / lean determination of the air-fuel ratio in each combustion chamber 3 is performed based on the detection value of the air-fuel ratio sensor 16. When the ECU 20 determines that the air-fuel ratio in the combustion chamber 3 is larger (lean) than the stoichiometric air-fuel ratio based on the detection value of the air-fuel ratio sensor 16, the fuel from the injector 12 is determined according to a predetermined procedure. Correct the injection amount to increase. When ECU 20 determines that the air-fuel ratio in combustion chamber 3 is smaller (richer) than the stoichiometric air-fuel ratio based on the detection value of air-fuel ratio sensor 16, the fuel from injector 12 is determined according to a predetermined procedure. Correct the injection amount to decrease.

  FIG. 2 is a functional block diagram of an ignition timing control system in the ECU 20 as the control device.

  As shown in FIG. 2, the ignition timing control system includes an ignition timing control unit 30 as an ignition timing control unit, an MFB calculation unit 40 as a combustion rate calculation unit, and a total heat generation as a total heat generation amount correction unit. A quantity correction unit 50.

  The ignition timing control unit 30 includes a PI control unit 31, a subtractor 32, an F / F control unit 33, and an adder 34. The ignition timing control unit 30 is calculated by the MFB calculation unit 40 at a predetermined time, for example, 8 ° after top dead center. A control command SA for controlling the ignition timing of each spark plug 7 of the engine 1 is calculated so that the combustion ratio MFBθ follows the target combustion ratio rMFB (for example, 60%).

  The PI control unit 31 performs a proportional operation and an integration operation on the deviation E between the target combustion ratio rMFB and the combustion ratio MFBθ calculated by the subtracter 32 and outputs the result to the adder 34.

  From the viewpoint of improving the disturbance characteristics of the feedback control system of the combustion ratio MFB, the F / F control unit 33 performs various operating conditions of the engine 1, such as the engine speed NE, charging, etc., in order to perform feedforward compensation. A compensation amount corresponding to the values of the efficiency KL, the intake valve Vi and / or the valve timing VT of the exhaust valve Ve, etc. is calculated and output to the adder 34. As a result, the compensation amount from the F / F control unit 33 is added to the control command calculated by the PI control unit 31 and is given to each spark plug 7 as the control command SA.

Based on the in-cylinder pressure P detected by the in-cylinder pressure sensor 15, the MFB calculation unit 40 generates a total heat generation amount THA generated from the start of combustion to the end of combustion in each combustion cycle, and reaches a predetermined time from the start of combustion. A heat generation amount HA generated until now and a combustion ratio MFB that is a ratio of the heat generation amount HA to the total heat generation amount THA are calculated. Further, the MFB calculating unit 40 calculates the total heat generation amount THA and the heat generation amount HA, the cylinder pressure P detected by the cylinder pressure sensor 15, and the cylinder volume V when the cylinder pressure P is detected as a predetermined index. It is calculated based on the product value P · V ^κ with the value raised to ^κ .

  Here, the MFB calculation method in the MFB calculation unit 40 will be described in more detail with reference to FIG.

The change pattern of the heat generation amount Q in the combustion chamber with respect to the crank angle and the change pattern of the product value ^PVκ with respect to the crank angle have a correlation as shown in FIG. In FIG. 3, the solid line represents the in-cylinder pressure P detected at predetermined minute crank angles in a predetermined model cylinder and the in-cylinder volume V at the time of detection of the in-cylinder pressure P raised to a power with a predetermined specific heat ratio κ. it is a plot of the product value ^PV κ of the value. In FIG. 3, the broken line indicates the heat generation amount Q in the model cylinder based on the following equation (1):

As calculated and plotted. In either case, for simplicity, κ = 1.32. In FIG. 3, −360 °, 0 ° and 360 ° correspond to the top dead center, and −180 ° and 180 ° correspond to the bottom dead center.

As can be seen from FIG. 3, the change pattern of the heat generation amount Q with respect to the crank angle and the change pattern of the product value PV ^κ with respect to the crank angle are substantially the same (similar), and in particular, combustion of the air-fuel mixture in the cylinder Before and after the start (at the time of spark ignition for a gasoline engine and at the time of compression ignition for a diesel engine) (for example, a range from about −180 ° to about 135 ° in FIG. 3), the change pattern of the heat generation amount Q and the product value PV ^It can be seen that the change pattern of ^κ agrees very well. That is, the product value ^PVκ can be said to be a value reflecting the combustion state in the combustion chamber.

As described above, since there is a correlation between the heat generation amount Q and the product value PV ^κ in the combustion chamber, the total heat generation amount generated from the start of combustion to the end of combustion in each combustion cycle is utilized. THA is obtained by the following equation (2). In the following equation, START indicates PV ^κ near the start of combustion, and END indicates PV ^κ near the end of combustion.

Further, the heat generation amount HA generated from the combustion start time to a predetermined crank angle θ in each combustion cycle is obtained by the following equation (3). In the following equation, θ represents PV ^κ at a predetermined crank angle θ.

Therefore, the combustion ratio MFB _θ that is the ratio of the heat generation amount HA to the total heat generation amount THA is obtained by the following equation (4).

The combustion ratio MFB _θ obtained in this way accurately reflects the degree of combustion in the combustion chamber.

In FIG. 2, when calculating the combustion rate MFB _θ , the total heat generation amount correction unit 50 compares the total heat generation amount THA with a standard value SHA set for each operation condition with respect to the total heat generation amount THA. Based on this, the total heat generation amount THA used for calculation of the combustion ratio MFB _θ is corrected.

  For example, the total heat generation amount correction unit 50 holds a standard value SHA set for each operation condition as a map value. The standard value SHA is preliminarily measured from experiments and the like as a total heat generation amount when normal combustion is performed for each operation condition, and is stored as a map value. The operating conditions here are the engine speed NE, the load factor or charging efficiency KL, and the valve timing VT, or other physical quantities including these information, and map values corresponding to these operating conditions. Stored in memory.

When the total heat generation amount THA obtained from the above equation (2) does not have a predetermined relationship with the standard value SHA obtained from the map, the standard value is used as the total heat generation amount THA used in the equation (4). Substitute SHA. That is, the combustion rate MFB _θ is obtained using the standard value SHA, not the total heat generation amount THA obtained from PV ^κ . The present invention is not limited to this configuration. The total heat generation amount THA is not changed to the standard value SHA, but the total heat generation amount THA is changed according to a deviation from the standard value SHA. Various modes such as correcting the above can be adopted.

  Next, an example of the correction process of the total heat generation amount THA when calculating the combustion ratio MFB will be described with reference to the flowchart of FIG. Note that the processing routine shown in FIG. 4 is repeatedly executed every predetermined time.

  First, the total heat generation amount THA calculated by the equation (2) is substituted into a variable V1 defined in the ECU 20 (step S1).

  Next, a map value (standard value SHA) corresponding to the current operating condition is substituted into a variable V2 defined in the ECU 20 (step S2).

  Then, a deviation X consisting of an absolute value of the difference between the variable V1 and the variable V2 is calculated (step S3), and it is determined whether the deviation X is smaller than a predetermined value α (step S4).

When the deviation X is smaller than the predetermined value α, it is determined that the combustion state is normal, and the combustion rate MFB _θ is calculated using the total heat generation amount THA obtained from PV ^κ (step S6).

On the other hand, when the deviation X is larger than the predetermined value α, it is determined that the current combustion state is the misfiring combustion state, the value of the variable V2 is substituted for the variable V1 (step S5), and the total obtained from PV ^κ The combustion rate MFB _θ is calculated using the standard value SHA instead of the heat generation amount THA (step S6).

  Here, the effect by correcting the total heat generation amount THA using the standard value SHA will be described with reference to FIG.

  FIG. 5A is a graph showing an example of a change in the amount of heat generated from the start of combustion to the end of combustion in one combustion cycle of the combustion chamber, and FIG. 5B is a graph of FIG. It is a graph which shows an example of the combustion ratio MFB calculated according to the process demonstrated in FIG. 4 using data. Note that graph (1) in FIG. 5A is data during normal combustion, graph (2) is data during misfiring, and graphs (1) and (2) in FIG. ) Respectively.

As can be seen from the graph (2) in FIG. 5B, the combustion rate MFB at the time of misfiring is calculated using the standard value SHA as the total heat generation amount THA, that is, the total amount at the time of normal combustion. Since the calorific value is used for calculation, there is a deviation between the target combustion rate rMFB and the combustion rate MFB _θ at a predetermined crank angle θ. Thereby, at the time of misfire-like combustion, a control command SA for changing this to the normal combustion state is accurately calculated by the ignition timing control unit 30 described above, and the misfire-like combustion state can be quickly resolved.

  FIG. 6 is a functional block diagram of an ignition timing control system according to another embodiment of the present invention. In FIG. 6, the same components as those in the ignition timing control system shown in FIG.

  The ignition timing control system shown in FIG. 6 further includes a standard value correction unit 60 as standard value correction means in addition to the ignition timing control system shown in FIG.

  The standard value correction unit 60 corrects the standard value SHA stored as a map value based on a plurality of total heat generation amounts THA calculated for one combustion chamber. As a correction method, for example, an average value μ and a fluctuation rate σ of a predetermined number of total heat generation amounts THA are calculated, and the standard value SHA held as a map value is updated using these values. be able to.

  The standard value SHA held as the map value may not be a desirable value due to the influence of the engine 1 over time, but the standard value correction unit 60 corrects the standard value SHA and optimizes it. Etc. can be removed.

  Here, an example of the correction process of the standard value SHA stored as the map value will be described with reference to the flowchart of FIG. The processing routine shown in FIG. 7 is repeatedly executed every predetermined time.

  First, the total heat generation amount THA calculated by the equation (2) is substituted into a variable V1 defined in the ECU 20 (step S11).

  Next, a map value (standard value SHA) corresponding to the current operating condition is substituted into a variable V2 defined in the ECU 20 (step S13).

  Next, a deviation X consisting of an absolute value of the difference between the variable V1 and the variable V2 is calculated (step S14), and it is determined whether the deviation X is smaller than a predetermined value α (step S15).

When the deviation X is smaller than the predetermined value α, it is determined that the combustion state is normal, the combustion rate MFB _θ is calculated using the total heat generation amount THA obtained from PV ^κ, and the value of the variable V1 is stored in the memory. Store (step S16). The calculated combustion ratio MFB _θ is used for ignition timing control.

When the deviation X is larger than the predetermined value α, it is determined that the current combustion state is a misfiring combustion state, the value of the variable V2 is substituted for the variable V1 (step S17), and the total heat generation obtained from PV ^{κ is} generated. The combustion ratio MFB _θ is calculated using the standard value SHA instead of the amount THA, and the value of the variable V1 at this time is stored in the memory (step S16).

  Next, an average value μ and a variation rate (standard deviation) σ of the value (total heat generation amount) of the n-point variable V1 stored in the memory in step S16 are calculated (step S18).

  After calculating the average value μ and the fluctuation rate σ, the counter n is incremented (step S19), and it is determined whether the counter n is smaller than the predetermined value β (step S20). If the counter n is greater than or equal to the predetermined value β, it is determined whether or not the value of the variable V2 is in the range of μ ± 3σ (step S21).

  When the value of the variable V2 is in the range of μ ± 3σ, the variable V2 is updated by substituting the average value μ into the variable V2 (step S22), and after resetting the counter n, the processing after step S14 is performed. Execute. That is, the average value μ is used for the variable V2 instead of the map value, and the standard value SHA is corrected (updated).

  When the value of the variable V2 is not in the range of μ ± 3σ, the processing after step S13 is executed. That is, the map value is substituted for the variable V2.

  According to the above processing, the standard value SHA as the map value is corrected and updated according to the current combustion state, so that the influence of the engine 1 such as aging can be removed.

  Next, another example of the correction process of the standard value SHA stored as the map value will be described with reference to the flowchart of FIG. The process is the same as that shown in FIG. 7 except for step S30 of the process shown in FIG.

  As shown in FIG. 8, when the value of the counter n reaches β in the process of step S20, the maximum value of the average value μ and the variation rate σ of the total heat generation amount calculated for each of the plurality of cylinders is the maximum. The average value μ and the variation rate σ of the cylinders that take values are selected (step S30).

As a result, the standard value SHA of all the cylinders is corrected by the common average value μ, and the combustion ratio MFB _θ can be calculated with higher accuracy.

It is a lineblock diagram showing an example of an engine (internal combustion engine) to which a control device concerning one embodiment of the present invention is applied. It is a functional block diagram of the ignition timing control system in the control apparatus which concerns on one Embodiment of this invention. It is a graph which shows the correlation with the change pattern of the amount of heat generation Q in a combustion chamber with respect to a crank angle, and the change pattern of product value PV ( ^kappa) with respect to a crank angle. It is a flowchart which shows an example of the correction process of the total heat generation amount THA at the time of calculating the combustion ratio MFB. (A) is a graph which shows an example of the change of the calorie | heat amount generate | occur | produced from the combustion start to the completion | finish of combustion in one combustion cycle of a combustion chamber, (B) uses the data of FIG. 5 (A). 5 is a graph showing an example of a combustion ratio MFB calculated according to the process described in FIG. 4. It is a functional block diagram of the ignition timing control system which concerns on other embodiment of this invention. It is a flowchart which shows an example of the correction process of the standard value SHA memorize | stored as a map value. It is a flowchart which shows the other example of a correction process of the standard value SHA memorize | stored as a map value. (A) is a graph which shows an example of the change of the calorie | heat amount generate | occur | produced from a combustion start to the completion | finish of combustion in one combustion cycle of a combustion chamber, (B) uses the data of FIG. 9 (A). It is a graph which shows an example of the change of the calculated combustion ratio MFB.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Cylinder block 3 ... Combustion chamber 4 ... Piston 5 ... Intake pipe 7 ... Spark plug 8 ... Surge tank 9 ... Air cleaner 10 ... Throttle valve 12 ... Injector 30 ... Ignition timing control part 31 ... PI control part 32 ... Subtraction Unit 33 ... F / F control unit 34 ... Adder 40 ... MFB calculation unit 50 ... Total heat generation amount correction unit 60 ... Standard value correction unit

Claims (6)

In-cylinder pressure detecting means for detecting the in-cylinder pressure in the combustion chamber of the internal combustion engine;
Based on the in-cylinder pressure detected by the in-cylinder pressure detecting means, the total heat generation amount generated from the start of combustion to the end of combustion in each combustion cycle, and the heat generation generated from the start of combustion to a predetermined time point A combustion rate calculating means for calculating an amount and a combustion rate that is a ratio of the heat generation amount to the total heat generation amount;
Ignition timing control means for controlling the ignition timing so that the combustion ratio calculated by the combustion ratio calculation means at the predetermined time follows a target value;
When calculating the combustion rate, based on a comparison between the total heat generation amount and a standard value set for each operating condition with respect to the total heat generation amount, a total amount for correcting the total heat generation amount used for the calculation is calculated. A control device for an internal combustion engine, comprising: a heat generation amount correction unit.   The total heat generation amount correction means calculates a combustion ratio using a standard value instead of the total heat generation amount when the total heat generation amount is not in a predetermined relationship with a standard value. The control apparatus for an internal combustion engine according to claim 1.   The combustion rate calculation means includes standard value correction means for correcting the standard value based on an average value of a plurality of total heat generation amounts calculated for one combustion chamber. 3. The control device for an internal combustion engine according to 2.   The standard value correcting means corrects the standard values respectively set for the plurality of combustion chambers based on one of a plurality of average values of the total heat generation amounts calculated for the plurality of combustion chambers. The control apparatus for an internal combustion engine according to claim 3.   The combustion ratio calculating means raises the heat generation amount and the total heat generation amount in the combustion chamber to the power of the cylinder pressure detected by the cylinder pressure detection means and the cylinder volume at the time of detection of the cylinder pressure by a predetermined index. The control device for an internal combustion engine according to any one of claims 1 to 4, wherein calculation is performed based on a product value of the calculated value.   6. The control apparatus for an internal combustion engine according to claim 1, wherein the operating condition includes any one of an engine speed, a charging efficiency, and a valve timing.

Images