JP6714526B2 - Misfire determination means and control device - Google Patents

Description

The present invention relates to a misfire determination means and a control device.

For example, Patent Document 1 discloses a combustion state detection device that calculates angular acceleration of a crank angle of an engine (internal combustion engine) and determines misfire of each cylinder based on each acceleration. In the combustion state detection device disclosed in Patent Document 1, misfire is determined when the angular acceleration deviation, which is the time deviation of the angular acceleration, is higher than a predetermined threshold for each cylinder, and the angular velocity deviation is less than or equal to the predetermined threshold. Has determined that there is no misfire.

Japanese Patent No. 535043

By the way, in the combustion chamber of the internal combustion engine, in addition to the complete misfire that is determined to be "misfire" in Patent Document 1, there is a possibility that misfire may occur but the determination threshold value is not exceeded, and thus the misfire is not determined. However, various combustion failures are considered, such as when the fuel injection amount is insufficient and the state is close to misfire. However, since the combustion state detection device in Patent Document 1 carries out a binary determination of a "misfiring" state and a "non-misfiring" state, is there a misfire as described above? Difficult to recognize ambiguous semi-misfire conditions.

The present invention has been made in view of the above-mentioned problems, and an object thereof is to appropriately detect a semi-misfire state of an internal combustion engine.

In order to achieve the above object, in the present invention, as the first means related to the misfire determination means, the misfire degree of the internal combustion engine is divided into three or more stages based on a combustion correlation parameter indicating a combustion state of the internal combustion engine. The configuration of judging is adopted.

As a second means related to the misfire determination means, in the first means related to the misfire determination means, a first parameter calculated based on the combustion correlation parameter and a second change amount of the first parameter over time A configuration is adopted in which the degree of misfire is determined based on the parameters.

As a third means related to the misfire determination means, in the first or second means related to the misfire determination means, the combustion correlation parameter is the instantaneous angular velocity of the crank angle of the internal combustion engine.

As a fourth means related to the misfire determination means, in any one of the first to third means related to the misfire determination means, a center point of the combustion correlation parameter in the case of a complete misfire state measured a plurality of times is calculated in advance. A configuration is adopted in which the determination threshold for the degree of misfire is set based on the distance from the center point.

As a first means related to the control device, a misfire determination means of any one of the first to fourth means related to the misfire determination means, a control value calculation means for calculating a control value of the internal combustion engine based on the degree of misfire, and And a control execution unit that performs control based on the control value.

As a second means related to the control device, in the first means related to the control device, the control value calculation means calculates a fuel injection amount as the control value, and the control execution means controls the fuel injection amount. The fuel injection control is performed based on the above.

As a third means related to the control device, in the first or second means related to the control device, the control value calculation means calculates an ignition timing in a combustion chamber of the internal combustion engine as the control value, The control executing means adopts a configuration of performing ignition control based on the ignition timing.

According to the present invention, the misfire determination means determines the combustion state of the internal combustion engine in three or more stages. Therefore, it is possible to determine a state other than the "misfire" and "not misfire" states, and a semi-misfire state that is close to the misfire determination threshold value that was conventionally determined as "not misfire" is determined. can do. That is, the misfire determination means can appropriately detect the semi-misfire state of the internal combustion engine.

It is a block diagram showing a system configuration of ECU in one embodiment of the present invention. It is a graph which shows an example of behavior of each combustion correlation parameter at the time of misfire occurrence in one embodiment of the present invention. It is an example of the two-dimensional mapping data in one embodiment of the present invention. 6 is a flowchart illustrating a misfire determination process of the ECU according to the embodiment of the present invention. 5 is a flowchart illustrating a combustion correction process of the ECU in the embodiment of the present invention.

Hereinafter, an ECU 1 (control device) will be described as an embodiment of a control device according to the present invention with reference to the drawings. In the present embodiment, the ignition control device according to the present invention is incorporated as one function of an ECU (Engine Control Unit) of a motorcycle. FIG. 1 is a block diagram showing the system configuration of the ECU 1 in this embodiment.

The ECU 1 is a control device that controls the internal combustion engine and each engine related to the internal combustion engine, and as shown in FIG. 1, the combustion state calculation unit 2, the misfire determination unit 3 (misfire determination means), and the advance value calculation. The unit 4 (control value calculation unit), the ignition control unit 5 (control execution unit), the fuel injection amount calculation unit 6 (control value calculation unit), and the fuel injection control unit 7 (control execution unit) are provided. There is. The combustion state calculation unit 2 acquires a crank angle from a rotation angle sensor of an internal combustion engine (not shown) and calculates an instantaneous angular velocity (combustion correlation parameter) of the crank angle. Further, the combustion state calculation unit 2 obtains the operating state from each of the internal combustion engine rotational speed sensor, the throttle opening sensor, and the intake pressure sensor, which are stored as operating state data.

The misfire determination unit 3 acquires the instantaneous angular velocity of the crank angle from the combustion state calculation unit 2 and applies a comb filter to the instantaneous angular velocity to calculate the parameter A (first parameter). Further, the misfire determination unit 3 calculates the amount of change over time of the parameter A as the parameter B (second parameter), thereby determining the misfire on the two-dimensional mapping with the parameter A as the first axis and the parameter B as the second axis. I do. Further, the misfire determination unit 3 displays the misfire on the display device of the vehicle when it is determined that the misfire is complete.

FIG. 2 is a graph showing an example of the behavior of each combustion correlation parameter when a misfire occurs in this embodiment. The upper part of FIG. 2 shows the instantaneous angular velocity data, the middle part shows the data of parameter A, and the lower part shows the data of parameter B. As shown in FIG. 2, by applying a comb filter to the instantaneous angular velocity of the crank angle, the parameter A attenuates components other than the change in the numerical value due to the occurrence of misfire. The parameter B is the time change amount of the parameter A, and it is possible to attenuate the noise caused by the swinging back of the numerical value generated in the parameter A immediately after the occurrence of misfire.

FIG. 3 is an example of the two-dimensional mapping data in this embodiment. In this embodiment, as shown in FIG. 3, two-dimensional mapping is created with the parameter A as the horizontal axis and the parameter B as the vertical axis. The misfire determination unit 3 includes a central point P (A1, B1) that is a determination standard that is previously obtained by an experiment, and a first threshold value X and a second threshold value that are determination threshold values for a two-dimensional distance from the central point P. It stores Y (X<Y). Further, in the mapping data shown in FIG. 3, an area where the parameter A is a predetermined value A2 (A1<A2) or more and an area where the parameter B is a predetermined value B2 (B1<B2) or more are not measured. When measuring data included in such a non-measurement area, the ECU 1 determines that the measurement error has occurred and skips the process.

The misfire determination unit 3 determines a complete misfire when the calculated parameters A and B are less than or equal to the first threshold X, and when the calculated parameters A and B are greater than the first threshold X and less than or equal to the second threshold Y, half misfire. To determine. Further, the misfire determination unit 3 determines that the calculated parameters A and B are normal when the calculated parameters A and B are larger than the second threshold value. In addition, the misfire determination unit 3 sets the second threshold value to 0 and the first threshold value to 1, and calculates the semi-misfire as a semi-misfire score according to the two-dimensional distance from the center point P, for example. The half-misfire score is stored each time the half-misfire determination is performed, and when the half-misfire score exceeds the score threshold, the combustion correction process is performed.

The advance value calculator 4 calculates the ignition advance value (ignition timing) of the internal combustion engine in accordance with the operating condition acquired from the combustion state calculator 2. Further, when the misfire determination unit 3 determines that the semi-misfire score exceeds the score threshold value, the advance angle calculation unit 4 performs a correction to advance or retard the ignition advance value. As the combustion correction process, the ignition control unit 5 executes ignition control of an ignition device (not shown) provided in the internal combustion engine based on the advance value (control value) calculated by the advance value calculation unit 4.

The fuel injection amount calculation unit 6 calculates the fuel injection amount from the combustion state calculation unit 2 to the combustion chamber of the internal combustion engine in accordance with the operating condition. Further, the fuel injection amount calculation unit 6 corrects the fuel injection amount with the increase or decrease of the fuel injection amount when the combustion correction process by the ignition control unit 5 is completed and the semi-misfire is not improved. As the combustion correction process, the fuel injection control unit 7 controls the fuel injection of a fuel injection device (not shown) provided in the internal combustion engine based on the fuel injection amount (control value) calculated by the fuel injection amount calculation unit 6. carry out.

The operation of the ECU 1 as the misfire determination device in this embodiment will be described with reference to FIG. FIG. 4 is a flowchart illustrating the misfire determination process of the ECU 1 according to this embodiment.
First, the combustion state calculation unit 2 calculates the combustion state (step S1). In step S1, the combustion state calculation unit 2 acquires the crank angle from the crank angle sensor and calculates the instantaneous angular velocity of the crank angle. Next, the misfire determination unit 3 calculates the parameters A and B (step S2). In step S2, the misfire determination unit 3 calculates and stores the parameter A by applying the comb filter to the instantaneous angular velocity. Further, the misfire determination unit 3 calculates the time change amount of the parameter A by differentiation and stores it.

Then, the misfire determination unit 3 calculates the distance L from the center point P (step S3). In step S3, the misfire determination unit 3 calculates the distance L between the parameter A and the parameter B obtained in step S2 and the center point P(A1, B1). Further, the misfire determination unit 3 determines whether the distance L is larger than the first threshold value X (step S4).

When the distance L is larger than the first threshold value X in step S4, that is, when the determination is YES, the misfire determination unit 3 determines whether the distance L is larger than the second threshold value Y (step S5). .. In step S5, when the distance L is larger than the second threshold value Y, that is, when the determination is YES, the misfire determination unit 3 determines that the combustion state is "normal" (step S6).

If the distance L is equal to or less than the first threshold value in step S4, that is, if the determination is NO, the misfire determination unit 3 determines "complete misfire" (step S7). Further, the misfire determination unit 3 displays on the display device a notification indicating complete misfire (step S8), and the process is completed.

If the distance L is equal to or less than the second threshold value in step S5, that is, if the determination is NO, the misfire determination unit 3 determines "semi-misfire" (step S9). Further, the misfire determination unit 3 calculates a score according to the size of the distance L (step S10). In step S10, the misfire determination unit 3 calculates the score by weighting the score such that the smaller the distance L, the higher the score, based on the calculation method stored in advance. The score is determined according to the distance L such that the score is 1.0 when the distance L is equal to the first threshold and the score is 0.0 when the magnitude is equal to the second threshold Y. Is set.

Next, the misfire determination unit 3 determines whether the score is equal to or greater than the score threshold (step S11). In step S11, the misfire determination unit 3 determines whether or not the score is equal to or greater than the score threshold stored in advance. A numerical value between 0.0 and 1.0 is set as the score threshold. If the score is equal to or greater than the score threshold in step S11, that is, if the determination is YES, the misfire determination unit 3 instructs the combustion correction process (step S12), and the process is completed. In step S12, the misfire determination unit 3 instructs the advance angle value calculation unit 4 to correct the advance angle value.

Next, the operation of the combustion correction process of the ECU 1 will be described with reference to FIG. FIG. 5 is a flowchart illustrating the combustion correction process of the ECU 1 in this embodiment.
First, the advance value calculator 4 corrects the advance value in the advance direction (step S21). In step S21, the advance angle value calculation unit 4 calculates the corrected advance angle value so that the current advance angle value is in a more advanced direction. The advance angle value calculation unit 4 determines the correction amount in step S21 depending on the calculated value of the distance L. Next, the ignition control unit 5 performs ignition control (step S22). In step S22, the ignition control unit 5 controls an ignition device (not shown) provided in the internal combustion engine based on the corrected advance value calculated by the advance value calculation unit 4.

Then, the misfire determination unit 3 determines whether the distance L is larger than the second threshold value Y (step S23). In step S23, the combustion state calculation part 2 and the misfire determination part 3 calculate the distance L after step S22 is performed based on steps S1 to S3 of the flowchart shown in FIG. 2 Comparison with the threshold value Y is performed. In step S23, when it is determined that the distance L is smaller than the second threshold value Y, that is, when the determination is YES, the semi-misfire state has not been improved, and therefore the advance angle value calculation unit 4 advances the advance angle. The value is corrected in the retard direction (step S24). In step S24, based on the instruction from the misfire determination unit 3, the advance angle value calculation unit 4 calculates the corrected advance angle value so as to be in the retard direction with respect to the current advance value. The advance value calculator 4 determines the correction amount in step S24 depending on the value of the distance L calculated in step S23. Next, the ignition control unit 5 performs ignition control (step S25).

Subsequently, the misfire determination unit 3 determines whether the distance L is larger than the second threshold value Y (step S26). In step S26, the misfire determination unit 3 calculates the distance L as in step S23, and compares the distance L with the second threshold value Y. When it is determined in step S26 that the distance L is smaller than the second threshold value Y, that is, when the determination is YES, the semi-misfire state has not been improved, and therefore the fuel injection amount calculation unit 6 determines the fuel injection amount. Correction is performed (step S27). In step S27, based on the instruction from the misfire determination unit 3, the fuel injection amount calculation unit 6 calculates the corrected fuel injection amount increased with respect to the current fuel injection amount. The fuel injection amount calculation unit 6 determines the correction amount in step S27 depending on the value of the distance L calculated in step S26. Further, the fuel injection control unit 7 executes fuel injection control (step S28). In step S28, the fuel injection control unit 7 controls the fuel injection device based on the corrected fuel injection amount.

Then, the misfire determination unit 3 determines whether the distance L is larger than the second threshold Y (step S29). In step S29, the misfire determination unit 3 calculates the distance L and compares it with the second threshold value Y, as in step S23. If it is determined in step S29 that the distance L is smaller than the second threshold value Y, that is, if the determination is YES, the semi-misfire state has not been improved, and therefore the fuel injection amount calculation unit 6 calculates the fuel injection amount. The weight reduction correction is performed (step S30). The fuel injection amount calculation unit 6 determines the correction amount in step S30 depending on the value of the distance L calculated in step S29. Further, the fuel injection control unit 7 executes fuel injection control (step S31). In step S31, the fuel injection control unit 7 controls the fuel injection device based on the corrected fuel injection amount. Finally, the fuel injection amount calculation unit 6 stores the fuel injection amount, and the process is completed.

If it is determined in step S23 that the distance L is equal to or greater than the second threshold value Y, that is, if the determination is NO, the advance angle calculation unit 4 corrects the advance angle because the semi-misfire state has been improved. The value is stored (step S33), and the process is completed. Further, if it is determined in step S26 that the distance L is equal to or greater than the second threshold value Y, that is, if the determination is NO, step S33 is similarly performed. Further, if it is determined in step S29 that the distance L is not less than the second threshold value Y, that is, if the determination is NO, step S32 is performed.

According to the ECU 1 in this embodiment, the misfire determination unit 3 evaluates the degree of misfire in three levels of "normal", "semi-misfire" and "complete misfire". By carrying out such an evaluation, the ECU 1 can grasp the case where there is an abnormality in the combustion state even in the combustion state which has been conventionally determined to be “no misfire”. That is, the ECU 1 in the present embodiment can appropriately detect the semi-misfire state of the internal combustion engine.

According to the ECU 1 in the present embodiment, the misfire determination unit 3 determines the degree of misfire based on the two-dimensional mapping of the parameter A based on the instantaneous angular velocity of the crank angle and the parameter B that is the time variation of the parameter A. ing. The parameter A is obtained by applying a comb filter to the measured instantaneous angular velocity data, and can attenuate the component due to misfire and extract the component due to misfire from the instantaneous angular velocity data. In addition, the parameter B can attenuate the component for swinging back the change due to the misfire from the data of the parameter A, and can remove the noise component in the determination of the degree of misfire. Therefore, the misfire determination can be performed more accurately by using such two parameters.

Further, according to the ECU 1 in the present embodiment, the center point P of the region indicating the complete misfire state is calculated, and the degree of misfire is determined based on the distance L from the center point. Thereby, for example, even when the numerical values in the parameter A or the parameter B have variations, it is possible to detect a complete misfire and a semi-misfire on the two-dimensional mapping.

In addition, the ECU 1 in the present embodiment executes the combustion correction process when it is determined that the state is the semi-misfire state. As a result, the ECU 1 can improve the semi-misfire state in which combustion is unstable. Therefore, it is possible to improve the running property and the fuel consumption.

Further, according to the ECU 1 in the present embodiment, the data for which "half-misfire" has been determined is further scored from 0 to 1.0, and the score stored in a predetermined period is added and evaluated. Thus, it is possible to detect the case where the semi-misfire state is frequently generated. Therefore, the behavior when the combustion state is unstable and the measurement noise can be separated.

The preferred embodiments of the present invention have been described above with reference to the drawings, but the present invention is not limited to the above embodiments. The shapes, combinations, and the like of the constituent members shown in the above-described embodiments are merely examples, and various changes can be made based on design requirements and the like without departing from the spirit of the present invention.

(1) In the above embodiment, the instantaneous angular velocity of the crank angle is used as the combustion correlation parameter, but the present invention is not limited to this. As the combustion correlation parameter, it is possible to apply the instantaneous engine speed or the time between pulses.

(2) Further, in the above-described embodiment, as the combustion correction processing, a configuration is adopted in which the fuel injection amount is corrected when the combustion state is not improved after the advance value is corrected. The invention is not limited to this. In the combustion correction process, it is also possible to correct the advance value after correcting the fuel injection amount.

(3) In addition, in the above-described embodiment, the degree of misfire is evaluated in three levels of "normal", "half-misfire", and "complete misfire". However, the present invention is not limited to this, and the misfire determination unit 3 may make a four-stage determination such as "normal", "possibly slightly misfired", "possibly misfired", or "completely misfired". It is possible. In this case, for example, the combustion correction process may be applied to a state where there is a possibility of misfire.

(4) In addition, when the ECU 1 determines “semi-misfire”, the combustion state calculation unit 2 records the load state of the internal combustion engine (internal combustion engine speed, throttle opening, etc.), and the misfire determination unit 3 It is also possible to adopt a configuration in which the above-mentioned combustion correction processing is executed when it is determined that the "half-misfire" has occurred a predetermined number of times in the load state in which is recorded.

(5) In addition, the misfire determination unit 3 may store the calculated score and perform the combustion correction process when the cumulative value of the half misfire scores recorded over a predetermined period exceeds the score threshold. It is possible.

(6) Further, the ECU 1 stores the judgment record of the half-misfire together with the data of the engine speed, the valve suction pressure, etc., so that it can be read out at the time of maintenance such as vehicle inspection, so that it can be used for detecting the cause of the defect. Is.

1...ECU
2... Combustion state calculation unit 3... Misfire determination unit 4... Advancement angle calculation unit 5... Ignition control unit 6... Fuel injection amount calculation unit 7... Fuel injection control unit

Claims (6)

The degree of misfire of the internal combustion engine is divided into three or more stages based on a first parameter calculated based on a combustion correlation parameter indicating a combustion state of the internal combustion engine and a second parameter which is a time change amount of the first parameter. Misfire determination means characterized by making the above determination. The misfire determination means according to claim 1 , wherein the combustion correlation parameter is an instantaneous angular velocity of a crank angle of the internal combustion engine . The center point of the combustion correlation parameter in the case of a complete misfire state measured a plurality of times is calculated in advance, and the determination threshold of the degree of misfire is set based on the distance from the center point. Or the misfire determination means described in 2. The misfire determination means according to any one of claims 1 to 3, a control value calculation means for calculating a control value of the internal combustion engine based on the degree of misfire determined by the misfire determination means, and based on the control value. A control device comprising: a control execution unit that performs control. The control value calculation means calculates a fuel injection amount as the control value,
The control execution means performs fuel injection control based on the fuel injection amount.
The control device according to claim 4, wherein: The control value calculation means calculates the ignition timing in the combustion chamber of the internal combustion engine as the control value,
The control execution means performs ignition control based on the ignition timing.
The control device according to claim 4 or 5, wherein:

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