JP2001182606A - Device and method for detecting combustion condition of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a detecting device for a combustion condition of an internal combustion engine for adequately detecting a misfire condition without errorneous diagnosis, even the pitch manufacturing error of a plate fitted to a crank shaft is out of an allowable range. SOLUTION: When fluctuation is judged in the combustion condition parameter of a cylinder group by a combustion condition fluctuation judging means 109, and the operation of correction quantity is allowed by a deciding means 110; the correction quantity for correcting a time signal is operated by a correction quantity operating means 108 based on deviation between the normal combustion value of the combustion condition parameter of the first cylinder group detected by a deviation detecting means 107, and the normal combustion value of the combustion condition parameter of a second cylinder group; and the time signal is corrected by a rotation time correcting means 102 based on operated correction quantity. The combustion condition parameter is operated by a combustion condition parameter operating means 103 using a corrected time signal, and the combustion condition is judged by a combustion judging means 104 from operated combustion condition parameter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting a combustion state of an internal combustion engine, and more particularly to an apparatus for erroneously detecting a pitch or error of a plate or a ring gear attached to a crankshaft for detecting a rotational angular speed, even if the error is outside an allowable range. TECHNICAL FIELD The present invention relates to a combustion state detection device and a combustion state detection method for an internal combustion engine that can detect a misfire without performing.

[0002]

2. Description of the Related Art Conventionally, there has been known a technique of detecting an operating state by measuring a rotation speed by utilizing a relationship between a torque generated by combustion of an engine and a rotation speed, and indirectly detecting a misfire. As an example, JP-A-58-51243 can be mentioned. This technique detects the rotation speed of the internal combustion engine at least at least two ignitions in one ignition cycle from the previous ignition to the current ignition, and determines the rotation speed of the internal combustion engine in the one ignition cycle based on a difference between the rotation speeds. A variation value is obtained, the rotational speed variation value obtained sequentially is statistically calculated, and the combustion state of the internal combustion engine is determined using the result of the calculation process.

The above-described method of detecting the rotational speed and determining the combustion state of the internal combustion engine is performed by detecting the rotational angle of a ring gear or a plate attached to a crankshaft. It is effective in the relatively low rotation speed range, but in the high rotation speed range, the variation due to the ring gear or plate pitch manufacturing error appears remarkably for each cylinder, and due to the pitch manufacturing error, the combustion state of the internal combustion engine is accurately determined. Judgment cannot be performed.

Therefore, as disclosed in Japanese Patent Application No. 9-34976, a technique has been devised for detecting the pitch manufacturing error of the plate by using PID control and correcting the rotational speed. Has been used to help.

[0005]

In the case where the above-mentioned pitch production error of the plate is detected by using the PID control, an operating region (rotational speed and engine load) to be corrected is set in advance, and the plate is mounted on the crankshaft. If the pitch production error of the plate is very large, the influence of the plate pitch production error may appear even outside the preset correction region, and in this case, the combustion condition parameter may be reduced due to the pitch production error. It may fluctuate and exceed the determination value that is regarded as misfire, resulting in erroneous diagnosis.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a combustion engine for an internal combustion engine which can accurately detect a misfire state without erroneous diagnosis even if a pitch production error of a rotation angle detecting member attached to a crankshaft is out of an allowable range. It is to provide a state detection device and a combustion state detection method.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, a feature of a combustion state detecting apparatus for an internal combustion engine according to the present invention is that a combustion state parameter of a group of cylinders is determined to be varied and corrected. When the calculation of the amount is permitted, a correction amount for correcting the time signal is calculated based on a deviation between the normal combustion value of the combustion state parameter of the first cylinder group and the normal combustion value of the combustion state parameter of the second cylinder group. A time signal is corrected based on the calculated correction amount, a combustion state parameter is calculated using the corrected time signal, and a combustion state is determined from the calculated combustion state parameter.

Specifically, the present invention provides the following apparatus and method.

The present invention relates to a combustion state detecting device for an internal combustion engine which detects a combustion state by a combustion state parameter calculated from a time signal for a crankshaft to rotate a predetermined angle, and a rotation time signal for detecting the rotation time signal. Detecting means; first normal combustion value detecting means for detecting a normal combustion value of a combustion state parameter of a first cylinder group including a set reference cylinder and an opposed cylinder facing the reference cylinder; and the first cylinder Second normal combustion value detecting means for detecting a normal combustion value of a combustion state parameter of the second cylinder group other than the group; a normal combustion value of the combustion state parameter of the first cylinder group; and a combustion state of the second cylinder group. Deviation detection means for detecting a deviation of the parameter from a normal combustion value, combustion state fluctuation determination means for determining the presence or absence of a change in the combustion state parameter, and Determining means for determining whether to permit operation of the correction amount for correcting the serial time signal, a correction amount calculating means for calculating the correction amount based on the deviation and the detected,
Rotation time correction means for correcting the time signal based on the calculated correction amount; combustion state parameter calculation means for calculating a combustion state parameter using the corrected time signal; and a combustion state from the calculated combustion state parameter. A combustion state determining means for determining, wherein the correction amount calculating means determines that there is a change in the combustion state parameter by the combustion state fluctuation determining means, and permits the calculation of the correction amount by the determining means. In this case, a combustion state detecting device for an internal combustion engine is provided, which calculates the correction amount when the correction is made.

Preferably, the correction amount calculating means performs PID control for calculating a correction amount so as to control the deviation to a predetermined value (zero).

Preferably, the correction amount calculating means retrieves a proportional gain, a differential gain, and an integral gain of the PID control from a rotation speed table or a misfire determination level map of the rotation speed and the engine load.

Preferably, the calculated correction amount includes:
An upper limiter and / or lower limiter are set.

Preferably, the combustion state fluctuation determining means compares the combustion state parameter with a determination level retrieved from a misfire determination level map of the engine speed and the engine load, and the combustion state parameter exceeds the determination level. In this case, it is determined that there is a change, and if it does not exceed, there is no change.

Preferably, the determination level is set for each cylinder.

Preferably, the deviation is a value obtained by averaging a normal combustion value of a combustion state parameter of the first cylinder group;
It is a difference or a ratio from a value obtained by averaging a normal combustion value of the combustion state parameter of the second cylinder group.

Preferably, the combustion state determining means compares the combustion state parameter with a misfire determination level retrieved from a misfire determination level map of the engine speed and the engine load, and determines whether the combustion state parameter exceeds the misfire determination level. If it is, it is determined that the combustion is abnormal, and if it does not exceed the misfire determination level, it is determined that the combustion is normal.

Preferably, the misfire determination level is corrected according to the correction amount.

Preferably, the misfire determination level is a value larger than the determination level.

Further, according to the present invention, in a method for detecting a combustion state of an internal combustion engine by detecting a combustion state by a combustion state parameter calculated from a rotation speed at which a crankshaft rotates a predetermined angle, a reference cylinder is set. And a normal combustion value of a combustion state parameter of a first cylinder group composed of a cylinder opposed to the reference cylinder and a normal combustion value of a combustion state parameter of a second cylinder group other than the first cylinder group. The deviation between the normal combustion value of the combustion state parameter of the first cylinder group and the normal combustion value of the combustion state parameter of the second cylinder group is calculated, and the presence or absence of a change in the combustion state parameter is determined. In this case, calculation of a correction coefficient for correcting the rotation speed is permitted, a correction coefficient for correcting the rotation speed is calculated based on the calculated deviation, and the rotation speed is compensated based on the calculated correction coefficient. And, then, the calculated combustion state parameter by using the rotational speed corrected to provide a combustion state detection method for an internal combustion engine and judging combustion state from the combustion state parameter the calculation.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a combustion state detecting device and a combustion state detecting method for an internal combustion engine according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a functional configuration of a combustion state detecting device for an internal combustion engine according to an embodiment of the present invention. As shown in FIG. 1, the present combustion state detection device includes a rotation time signal detection unit 101 that detects a time signal for rotating a crankshaft by a predetermined angle, a set reference cylinder, and an opposing cylinder facing the reference cylinder. Normal combustion value detecting means 105 for detecting a normal combustion value of the combustion state parameter of the first cylinder group composed of
A second normal combustion value detecting means 10 for detecting a normal combustion value of a combustion state parameter of a second cylinder group other than the first cylinder group.
6, a deviation detecting means 107 for detecting a deviation between a normal combustion value of the combustion state parameter of the first cylinder group and a normal combustion value of the combustion state parameter of the second cylinder group, and judging whether or not the combustion state parameter has changed. Combustion state fluctuation determination means 109
Determining means 110 for determining whether to permit the calculation of a correction amount for correcting the time signal based on the presence or absence of a change in the combustion state parameter, and calculating a correction amount for correcting the time signal based on the detected deviation Correction amount calculating means 108, a rotation time correcting means 102 for correcting a time signal based on the calculated correction amount, and a combustion state parameter calculating means 103 for calculating a combustion state parameter using the corrected time signal.
And a combustion state determining means 104 for determining a combustion state from the calculated combustion state parameter.

Next, the processing procedure of the combustion state detection operation of the combustion state detection device of FIG. 1 will be described. First, the number of rotations at which the crankshaft rotates a predetermined angle is detected. Next, a reference cylinder is set, a normal combustion value of a combustion state parameter of a first cylinder group including the reference cylinder and an opposite cylinder facing the reference cylinder is detected, and a second cylinder other than the first cylinder group is detected. The normal combustion value of the group combustion state parameter is detected. Then, a deviation between the normal combustion value of the combustion state parameter of the first cylinder group and the normal combustion value of the combustion state parameter of the second cylinder group is calculated. Next, the presence or absence of a change in the combustion state parameter is determined, and if it is determined that there is a change, calculation of a correction coefficient for correcting the rotation speed is permitted, and a correction coefficient for correcting the rotation speed based on the calculated deviation is calculated. The rotation speed is corrected based on the calculated correction coefficient. Then, a combustion state parameter is calculated using the corrected rotation speed, and a combustion state (presence or absence of misfire) is determined from the calculated combustion state parameter.

If it is determined that there is no fluctuation, the calculation of the correction amount for correcting the rotational speed is prohibited.

FIG. 2 shows an example of an internal combustion engine system provided with the combustion state detecting device of FIG. Hereinafter, an internal combustion engine system will be described as an example.

As shown in FIG. 2, the engine comprises an internal combustion engine, an intake system, and an exhaust system. The internal combustion engine is provided with an ignition device 201, a fuel injection device 202, and rotation speed detecting means 203. An air cleaner and a flow rate detecting means 204 are attached to the intake system, and an air-fuel ratio sensor 205 and a three-way catalyst 206 are attached to the exhaust system.

The internal combustion engine control unit 207 takes in the output signal Qa of the flow rate detection unit 204 and the rotation speed Ne of the ring gear or plate 208 by the rotation speed detection unit 203, calculates the fuel injection amount Ti, and calculates the fuel injection amount Ti. Control the injection volume.

The internal combustion engine control unit 207 detects the air-fuel ratio in the internal combustion engine from the air-fuel ratio sensor 205 and sets the fuel injection amount T so that the air-fuel ratio in the internal combustion engine becomes the stoichiometric air-fuel ratio.
The air-fuel ratio feedback control for correcting i is performed. In addition,
In the present embodiment, a four-cylinder engine will be described as an example, but the present invention is not limited to this.

FIG. 3 shows the rotation speed with respect to the crank angle of the engine when a misfire occurs. The solid line is the waveform when the four cylinders misfired, and the broken line is the one when the combustion state is normal.

Referring to FIG. 3, a rotation speed measurement section (hereinafter, referred to as a window) for each cylinder will be described. The TDC (top dead center) of each cylinder is detected based on the reference signal REF.
The first crank angle is obtained from the TDC using the angle signal POS and is set as the window start point Ws. The second crank angle is determined from the window start point Ws using the same angle signal POS, and the window width from the first crank angle to the second crank angle is defined as the window width W.

Now, let TDATA (n) be the window passage time of the cylinder in the ignition cycle, and obtain the combustion state parameter D1A from equation (1).

D1A = {(TDATA (n) −TDATA (n−1)} / TDATA (n) ³ ... (1) where TDATA (n) is the value of the cylinder currently in the ignition cycle. Window W transit time TDATA (n-1): Window W transit time of the cylinder in the previous ignition cycle D1A: Combustion state parameter Equation (1) indicates that when the combustion state of the engine is normal, the window transit time of each cylinder is Since they are equal, the combustion state parameter D1A indicates zero.

As shown in FIG. 4, when the engine misfires, no torque is generated in the misfiring cylinder and the number of revolutions decreases, so that the value of TDATA increases and the combustion state parameter D1A has a certain positive value. Therefore, the presence or absence of a misfiring cylinder can be detected by comparing the combustion state parameter D1A with a preset value.

The method of detecting the presence or absence of a misfired cylinder is effective in a relatively low rotational speed region, but in a high rotational speed region, as shown in FIG. , So that detection becomes impossible. In the high rotation region, vibration occurs because TDATA contains a measurement angle error due to a manufacturing error of the plate or the ring gear. Therefore, the combustion state parameter D1A calculated by the equation (1) also vibrates because the equation (1) is a difference equation. The combustion state parameter D1A at the time of misfire is buried in this vibration width, and the misfire cannot be detected.

Therefore, when the TDATA of FIG. 5 is carefully observed, the TDATA between the 1 and 4 cylinders (opposite cylinders) gradually decreases due to the inertia of the crankshaft.
There is no difference. In addition, the T of two and three cylinders (competent cylinders)
The same applies to DATA.

However, there is a clear deviation between TDATA of the non-opposite cylinders of 1 and 3 cylinders or 1 and 2 cylinders (4 and 2 cylinders, 4 and 3 cylinders). This is a measurement error caused by a manufacturing error of the ring gear.

Therefore, a reference cylinder is set, and a correction coefficient for adjusting the TDATA level of the cylinder group consisting of the reference cylinder and the cylinder opposite thereto to the TDATA of the other cylinder group is applied. In the present embodiment, the reference cylinder is # 2 cylinder, the opposite cylinder is # 3 cylinder, and the other cylinder groups are # 1 and # 4 cylinders. This correction coefficient is hereinafter referred to as a pitch error correction coefficient PE
Multiplying the pitch error correction coefficient PEC by TDATA is referred to as pitch error correction.

FIG. 6 shows the combustion state parameter D1A when the pitch error correction coefficient PEC is set to 0.999. From FIG. 6, by performing pitch error correction,
Even in a high rotation region, a misfire can be detected by setting an appropriate determination level.

Next, means for calculating the pitch error correction coefficient will be described. Normally, the pitch error correction coefficient PEC is changed so that the misfire S / N ratio (the ratio of the peak of D1A at the time of misfire and the peak of D1A at the time of no misfire) is sequentially calculated so that the maximum value is obtained. A method is conceivable.

However, it is impossible to forcibly misfire in order to obtain the S / N ratio. Therefore, a parameter that is proportional (or inversely proportional) to the S / N ratio is introduced. As a candidate for this parameter, there is a deviation (inversely proportional to the S / N ratio) of the combustion state parameter D1A between the non-opposed cylinders. This deviation is obtained by comparing the level 1 and level 2 of the combustion state parameters shown in FIG.
Controlling this deviation to a predetermined value (preferably zero) will ensure the maximum S / N ratio.

Therefore, PID control, which is widely used in control engineering, is used as means for making the above-mentioned deviation zero. In general, when controlling a control amount of a plant to a target value, PID control adds all the proportional components of the deviation, the derivative of the deviation, and the integral of the deviation to the deviation between the control amount and the target value. Is a control method for calculating the operation amount and controlling the control amount to the target value. This PID control is
Used for calculating the pitch error correction coefficient PEC.

In this correction method, an operation region to be corrected is determined in advance, and when the operation enters this region, the correction is performed. One of the conditions for determining this correction region is that the plate pitch manufacturing error is within a tolerance (the tolerance is that when the plate pitch manufacturing error actually occurs in a misfire in the entire operation region). Must be smaller than the minimum value of the decrease in the rotational angular velocity of the motor). In a vehicle equipped with a plate within this tolerance, the correction region is determined so that correction is prohibited in a low rotation region where the influence of the pitch production error does not appear, and correction is performed in a high rotation region where the influence is produced.

However, it is assumed that, due to variations in mass production of the plate, the pitch manufacturing error of the plate cannot always be suppressed to within the tolerance, and an erroneous diagnosis occurs outside the correction region (low rotation region).

Therefore, except for the concept of the correction region, the combustion state parameter is not a fluctuation that can be regarded as misfire, but if the combustion state parameter has fluctuated to some extent, the correction is performed even in the low rotation speed region. In other words, if the plate is within tolerance,
The low rotation region is not corrected, but if the plate is out of tolerance, the low rotation region is corrected. As a result, fluctuations are suppressed and erroneous diagnosis is prevented.

As another alternative, a method of using the gain of the PID control as a table of the number of revolutions is also conceivable. In this case, a small correction gain is set in the low rotation region, and a large correction gain is set in the high rotation region. However, at this time, even in the low rotation region, since the correction is made with a small correction gain, it is effective when the plate pitch manufacturing error is large, but is stable when the plate pitch manufacturing error is small. It becomes unstable by control.

Therefore, as a countermeasure, the misfire determination level is corrected (corrected downward) by the pitch error correction coefficient calculated by the PID control so that the misfire can be reliably detected at the time of misfire. In the low rotation region, the absolute value of the deviation of the pitch error correction coefficient from 1.0 is a measure of the decrease in the S / N ratio.

FIG. 7 shows a detailed block diagram of misfire diagnosis performed by the combustion state detecting device of FIG. The window transit time TDATA is detected (block 701).
Then, the TDATA of the one and four cylinders is multiplied by the pitch error correction coefficient PEC to correct the TDATA (block 70).
2). Then, the TDATA corrected in block 702
, The combustion state parameter D1A is calculated from the above-described equation (1) (block 703).

Next, the calculated combustion state parameter D1
If A is larger than the misfire judgment level retrieved from the misfire judgment level map (block 712) of the detected rotation speed (block 710) and the engine load (block 711), it is counted as a misfire (block 704).

The average value of the combustion state parameter D1A of the reference cylinder and the opposed cylinders (2, 3 cylinders) is calculated (block 705), and the average value of the combustion state parameter D1A of the other cylinder groups (1, 4 cylinders) is calculated. A calculation is made (block 706). Then, a deviation ε of the average value is obtained, and a pitch error correction coefficient PEC is calculated by PID control (block 70).
7).

Then, the TDA of the first and fourth cylinders detected next time is
TA is multiplied by the calculated pitch error correction coefficient PEC.

At this time, the variation of the combustion state parameter D1A is detected (block 708), and the combustion state parameter D1 is detected.
If 1A is within the predetermined range, it is determined that the correction has to be performed if the combustion state parameter D1A is not within the predetermined range. Then, the correction is continued (block 709).
Next, the misfire diagnosis logic of FIG. 7 will be described with reference to the PAD diagram of FIG. Hereinafter, each step will be described. The process is performed for each ignition. The window transit time TDATA is measured (step 801), and step 8 is performed by the ignition cylinder.
The processes of 03 to 806 are performed (step 802). That is, the TDATA of one and four cylinders is multiplied by the pitch error correction coefficient. TDATA of a few cylinders is not multiplied by the pitch error correction coefficient.

Then, the combustion state parameter D1A is obtained from equation (1) (step 807). If it is determined that the vehicle is within the diagnosis area (eg, running on a bad road) (step 808), if the combustion state parameter D1A is equal to or higher than the misfire determination level L1, it is determined that a misfire has occurred (step 809), and misfire count processing is performed (block 810). ). If it is not determined that a misfire has occurred, the combustion state parameter falls within a predetermined range (from L2 to L2).
3), the pitch error correction coefficient is not updated, and if it is not within the predetermined range (between L2 and L3),
In order to suppress the fluctuation, a calculation of a pitch error correction coefficient is performed (step 811).

The calculation of the pitch error correction coefficient is performed in step 8
If the ignition cylinder is one or four cylinders (step 812), an average value D1AM1 of the combustion state parameters D1A of the one and four cylinders is obtained (step 81).
3). If the ignition cylinder is a few cylinders, an average value D1AM2 of the combustion state parameters D1A of the two or three cylinders is obtained (step 814).

Then, the deviation ε between D1AM1 and D1AM2 is obtained (step 815). Then, the deviation ε is multiplied by Kp to obtain a proportional component P (step 816). Further, the difference between the deviation ε and the deviation εold at the time of the previous calculation is multiplied by Kd to obtain a differential D (step 817). Further, the deviation ε is integrated, and the integrated value IE is multiplied by Ki to obtain an integral I (steps 818 and 819).

Next, the pitch error correction coefficient PEC is calculated by adding P, I and D, and subtracting the value obtained by multiplying the coefficient K from 1.0 (step 820). Lastly, upper and lower limiters of the pitch error correction coefficient are checked (step 821).
d, Deviation integration IE is IEold, D1AM1 is D1AM1ol
d, D1AM2 is D1AM2old. At step 823, TDATAF is set to TDATAFold (step 822).

FIG. 9 shows an example of the effect of this embodiment. FIG.
In the embodiment of FIG. 9B, the pitch error correction is performed in the low rotation speed region as compared with the comparative example of FIG. 9A, and misfire can be detected without erroneous diagnosis.

FIG. 10 shows another example of a detailed block diagram of misfire diagnosis performed by the combustion state detecting device of FIG. Window transit time TDAT from block 1001
A is detected (block 1001). Then, the TDATA of the one and four cylinders is multiplied by the pitch error correction coefficient PEC to correct the TDATA (block 1002). afterwards,
A combustion state parameter D1A is calculated from the corrected TDATA from equation (1) (block 1003).

Next, the presence or absence of a misfire is determined by comparing the combustion state parameter D1A with a misfire determination level (block 1).
004). However, the misfire determination level is based on the detected rotation speed (block 1009) and the engine load (block 101).
A value obtained by multiplying the value retrieved from the misfire determination level map (block 1011) with the value retrieved from a pitch error correction coefficient table (block 1008), which will be described later, as the misfire determination level.

Next, an average value of the combustion state parameters D1A of the reference cylinder and the opposed cylinders (2, 3 cylinders) is calculated (block 1005), and the average value of the combustion state parameters D1A of the other cylinder groups (1, 4 cylinders) is calculated. Calculate the average (block 10)
06). Then, a deviation ε of the average value is obtained, and a pitch error correction coefficient PEC is calculated by PID control (block 1007). At this time, control is performed by using the gain of the PID control as a function of the rotation speed (when the rotation speed is high, the gain is increased,
If it is small, decrease the gain).

Then, the TDA of the first and fourth cylinders detected next time is
TA is multiplied by the calculated pitch error correction coefficient.

Here, the misfire determination level is corrected based on the obtained pitch error correction coefficient (block 10).
08). This is because in the low rotation region, the absolute value of the deviation of the pitch error correction coefficient from 1.0 can be considered as a measure for reducing the S / N.

Next, the misfire diagnosis logic of FIG.
This will be described with reference to the PAD diagram of FIG. Hereinafter, each step will be described. The process is performed for each ignition. Window transit time T
DATA is measured (step 1101), and the processing of steps 1103 to 1106 is performed by the ignition cylinder (step 1102). That is, the TDATA of one and four cylinders is multiplied by the pitch error correction coefficient. Two or three cylinder TDATA
Is not multiplied by the pitch error correction coefficient.

Then, the combustion state parameter D1A is obtained from equation (1) (step 1107). When it is determined that the vehicle is within the diagnosis area (such as running on a bad road) (step 110)
8) The correction value KTH retrieved from the table of the pitch error correction coefficient PEC is obtained (step 1109), and the correction value KTH is multiplied by the determination value LTH retrieved from the map of the engine speed and the engine load to obtain the misfire determination level. L1 is obtained (step 1110).

If the combustion state parameter D1A is equal to or higher than the misfire determination level L1, misfire is determined (step 1111), and misfire count processing is performed (block 11).
12). If it is not determined that a misfire has occurred, a pitch error correction coefficient is calculated.

The calculation of the pitch error correction coefficient is performed in step 1
If the ignition cylinder is one or four cylinders (step 1113), an average value D1AM1 of the combustion state parameters D1A of the one and four cylinders is obtained (step 1114). If the ignition cylinder is two or three cylinders, an average value D1AM2 of the combustion state parameters D1A of two or three cylinders is obtained in step 1115 (in step 1115).

Then, the deviation ε between D1AM1 and D1AM2 is obtained (step 1116). And the deviation ε
Is multiplied by Kp to obtain a proportional component P (step 1117).
Further, the difference between the deviation ε and the deviation εold at the time of the previous calculation is multiplied by Kd to obtain a differential D (step 1118). Further, the deviation ε is integrated, and the integrated value IE is multiplied by Ki to obtain an integral I (steps 1119 and 1120).

Next, the PID control gain K is searched from the rotation speed table (step 1121), P, I and D are added, and the value obtained by multiplying the gain K is subtracted from 1.0 to obtain the pitch. An error correction coefficient PEC is calculated (step 1122). Finally, the upper and lower limiters of the pitch error correction coefficient are checked (step 1123). For the next calculation, the deviation ε is set to εold, and the deviation integration IE is set to IEol.
d, D1AM1 is D1AM1old, D1AM2 is D1AM
2 old Also, in step 1125, TDATAF
Is set to TDATAFold (step 1124).

In the methods shown in FIGS. 10 and 11, FIG.
As shown in (b), the pitch error correction is performed in the low rotation region, so that even if the plate pitch manufacturing error is large, it is possible to diagnose that misfire is detected without erroneous diagnosis.

[0068]

According to the present invention, even if the pitch production error of the rotation angle detecting member attached to the crankshaft is out of the allowable range, the misfire state can be accurately detected without erroneous diagnosis. The reliability of the combustion state detection device for the internal combustion engine can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a functional configuration of a combustion state detection device for an internal combustion engine according to an embodiment of the present invention.

FIG. 2 is a diagram showing an example of an internal combustion engine system including the combustion state detecting device of FIG.

FIG. 3 is a diagram showing a rotation speed with respect to a crank angle of an engine when a misfire occurs.

FIG. 4 is a diagram showing a relationship between a window passage time TDATA at the time of misfire and a combustion state parameter D1A.

FIG. 5 is a window transit time T when a pitch error occurs.
It is a figure showing the relation between DATA and combustion state parameter D1A.

FIG. 6 shows a window transit time T after pitch error correction.
It is a figure showing the relation between DATAF and combustion state parameter D1A.

FIG. 7 is a detailed block diagram of a misfire diagnosis performed by the combustion state detection device of FIG. 1;

FIG. 8 is an explanatory diagram for explaining the misfire diagnosis logic of FIG. 7 using a PAD diagram.

FIG. 9 is a diagram showing an example of an effect of the embodiment.

FIG. 10 is a diagram showing another example of a detailed block diagram of misfire diagnosis performed by the combustion state detection device of FIG. 1;

FIG. 11 is an explanatory diagram illustrating the misfire diagnosis logic of FIG. 10 using a PAD diagram.

[Explanation of symbols]

101: rotation time signal detection means, 102: rotation time correction means, 103: combustion state parameter calculation means, 104:
Combustion state determining means, 105: first normal combustion value detecting means, 106: second normal combustion value detecting means, 107: deviation detecting means, 108: correction amount calculating means, 109: combustion state fluctuation determining means, 201 ... Ignition device, 202: fuel injection device, 203: rotation speed detection device, 204: flow rate detection device,
205: air-fuel ratio detection device, 206: catalyst, 207: internal combustion engine control device, 208: plate or ring gear

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Akito Numata 2477 Takaba, Hitachinaka-shi, Ibaraki F-term in Hitachi Car Engineering Co., Ltd. 3G084 DA27 EA11 EB08 EB14 EB15 EB25 FA18 FA24 FA33 FA38 FA39

Claims (11)

[Claims] 1. A combustion state detection device for an internal combustion engine for detecting a combustion state by a combustion state parameter calculated from a time signal for a crankshaft to rotate a predetermined angle, wherein a rotation time signal detection means for detecting the rotation time signal. A first normal combustion value detecting means for detecting a normal combustion value of a combustion state parameter of a first cylinder group including a set reference cylinder and an opposite cylinder facing the reference cylinder;
A second normal combustion value detection means for detecting a normal combustion value of a combustion state parameter of a second cylinder group other than the cylinder group;
Deviation detecting means for detecting a deviation between a normal combustion value of the combustion state parameter of the cylinder group and a normal combustion value of the combustion state parameter of the second cylinder group; and a combustion state fluctuation judgment for judging whether or not the combustion state parameter has changed. Means, determining means for determining whether to permit calculation of a correction amount for correcting the time signal based on the presence or absence of the fluctuation, and correction amount calculating means for calculating the correction amount based on the detected deviation. A rotation time correction unit that corrects the time signal based on the calculated correction amount, and a combustion state parameter calculation unit that calculates a combustion state parameter using the corrected time signal.
Combustion state determination means for determining a combustion state from the calculated combustion state parameter, wherein the correction amount calculation means determines that there is a change in the combustion state parameter by the combustion state change determination means, and A means for calculating the correction amount when the calculation of the correction amount is permitted by the means. 2. A combustion state detection system according to claim 1, wherein said correction amount calculating means performs PID control for calculating a correction amount so as to control said deviation to a predetermined value (zero). apparatus. 3. The correction amount calculating means according to claim 2, wherein said proportional gain, differential gain and integral gain of said PID control are stored in a table of rotation speed or a misfire determination level map of rotation speed and engine load. A combustion state detection device for an internal combustion engine, characterized in that a search is performed from a search. 4. The combustion state detecting device for an internal combustion engine according to claim 2, wherein an upper limiter and / or a lower limiter are set as the calculated correction amount. 5. The combustion state variation determining means according to claim 1, wherein the combustion state parameter is compared with a determination level retrieved from a misfire determination level map of engine speed and engine load, and the combustion state parameter is determined by the determination level. A combustion state detection device for an internal combustion engine, characterized in that it determines that there is a change if it exceeds the limit, and that there is no change if it does not exceed the limit. 6. A combustion state detecting device for an internal combustion engine according to claim 5, wherein said determination level is set for each cylinder. 7. The method according to claim 1, wherein the deviation is equal to the first value.
An internal combustion engine characterized by a difference or a ratio between a value obtained by averaging the normal combustion value of the combustion state parameter of the cylinder group and a value obtained by averaging the normal combustion value of the combustion state parameter of the second cylinder group. Combustion state detection device. 8. The combustion state determination means according to claim 1, wherein said combustion state determination means compares said combustion state parameter with a misfire determination level retrieved from a misfire determination level map of engine speed and engine load. A combustion state detection device for an internal combustion engine, characterized by determining that combustion is abnormal when the level exceeds the level, and determining that combustion is normal when the level does not exceed the misfire determination level. 9. The apparatus according to claim 8, wherein the misfire determination level is corrected in accordance with the correction amount. 10. A combustion state detecting device for an internal combustion engine according to claim 5, wherein said misfire determination level is a value larger than said determination level. 11. A method for detecting a combustion state of an internal combustion engine in which a combustion state is detected by a combustion state parameter calculated from a rotation speed at which a crankshaft rotates a predetermined angle, wherein a reference cylinder is set, and the reference cylinder and the reference cylinder are set. A normal combustion value of a combustion state parameter of a first cylinder group composed of an opposed cylinder facing the first cylinder group and a normal combustion value of a combustion state parameter of a second cylinder group other than the first cylinder group. The deviation between the normal combustion value of the combustion state parameter of the second combustion engine and the normal combustion value of the combustion state parameter of the second cylinder group is calculated in advance.
On the other hand, it is determined whether there is a change in the combustion state parameter, and when it is determined that there is a change, calculation of a correction coefficient for correcting the rotation speed is permitted, and a correction coefficient for correcting the rotation speed based on the calculated deviation is calculated. An internal combustion engine that corrects a rotation speed based on the calculated correction coefficient, calculates a combustion state parameter using the corrected rotation speed, and determines a combustion state from the calculated combustion state parameter. Combustion state detection method.