JP6484306B2 - Internal combustion engine misfire detection device - Google Patents

Description

  The present invention relates to an internal combustion engine misfire detection device that detects misfire of a 2-stroke or 3-cylinder 4-stroke internal combustion engine, for example.

  In an internal combustion engine, for example, a two-cylinder or three-cylinder four-stroke engine, output is generated by repeating four strokes of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke. The engine control device controls the timing of fuel injection, ignition, and the like by determining each stroke of the engine. At this time, an engine misfire that does not ignite at the ignition timing may occur depending on the operating state of the engine. When such engine misfire occurs, drivability deteriorates or exhaust performance deteriorates. For this reason, conventionally, by detecting engine misfire, the driver is informed based on the detection result, and brought into the maintenance shop, or the operating state of the engine is controlled to deteriorate the drivability or exhaust performance. It is done to reduce.

  Under such circumstances, Patent Document 1 relates to a misfire detection device for an internal combustion engine having a plurality of cylinders, calculates a relative speed parameter using a rotational speed parameter corresponding to the rotational speed of the internal combustion engine, and calculates an integrated value of the relative speed parameter. The structure which detects the presence or absence of misfire of an internal combustion engine based on this is disclosed.

JP 2007-198368 A

  However, according to the study of the present inventor, in the apparatus configuration of Patent Document 1, the integrated section of the integrated value of the relative speed parameter of each cylinder is set to a length obtained by dividing the crank angle 720 by the number of cylinders. Therefore, the integration interval in a single-cylinder engine mounted on a motorcycle or the like is an interval during which the crankshaft rotates 720 degrees, and the integration interval in a 2-cylinder or 3-cylinder engine mounted on a motorcycle or the like is a crankshaft. Is a relatively long section because it rotates 360 degrees or 240 degrees, and there is a possibility that the dispersion of the integrated value may increase due to the influence of inertial force or friction. In this case, misfire The risk of false detection is increased.

  The present invention has been made through the above-described studies. The risk of misdetecting misfire of an internal combustion engine by detecting misfire of a 4-stroke internal combustion engine using an accumulated value accumulated in an appropriate accumulation interval. An object of the present invention is to provide an internal combustion engine misfire detection device capable of reducing the above.

In order to achieve the above object, according to the first aspect of the present invention, in the internal combustion engine misfire detection apparatus that detects misfire of a 4-stroke internal combustion engine, the present invention responds to the rotational speed of the internal combustion engine for each predetermined crank angle. A rotation speed parameter; a reference value for the rotation speed parameter; a deviation between the reference value and the rotation speed parameter; a calculation unit for calculating an integrated value of the deviation; A determination unit that performs misfire determination based on the internal combustion engine , wherein the internal combustion engine includes a plurality of cylinders, and each cylinder is ignited so that expansion strokes of the cylinders do not overlap, and the calculation unit includes the internal combustion engine An integration interval of the integrated value when the engine is equal to or higher than a predetermined number of revolutions is set to be shorter than the length from the time of ignition of the cylinder performing misfire determination to the time of ignition of the next ignition cylinder. Previous Said integrating period when less than a predetermined rotational speed, which is an internal combustion engine misfire detection apparatus set shorter than the integration interval in the case of the above predetermined number of revolutions.

The present invention, in addition to the first aspect, the front Symbol calculating unit, to a setting of individual lengths the integrating period for each cylinder and the second aspect.

The present invention, in addition to the first or second aspect, before Symbol calculating unit, the integrating period when the internal combustion engine is lower than the predetermined rotational speed, the end from the start of the expansion stroke of the internal combustion engine Set to a length up to the time, and the integration interval when the internal combustion engine is equal to or higher than the predetermined rotation speed is a length from the start of the expansion stroke of the internal combustion engine to just before the ignition of the next cylinder to be ignited This is the third aspect.

In addition to any one of the first to third aspects, the present invention includes a filter that removes a high frequency component contained in an electrical signal indicating the rotation speed parameter, and removes the high frequency component by the filter. Calculating the reference value of the rotational speed parameter indicated by the electrical signal, and calculating the deviation between the reference value and the rotational speed parameter indicated by the electrical signal from which a high frequency component has been removed by the filter. Is the fourth aspect.

In the internal combustion engine misfire detection apparatus according to the first aspect of the present invention, in the internal combustion engine misfire detection apparatus for detecting misfire of a 4-stroke internal combustion engine, a rotational speed corresponding to the rotational speed of the internal combustion engine for each predetermined crank angle. A parameter is calculated, a reference value of the rotation speed parameter is calculated, a deviation between the reference value and the rotation speed parameter is calculated, a calculation unit that calculates an integrated value of the deviation, and a determination that performs misfire determination based on the integrated value The internal combustion engine includes a plurality of cylinders, and each cylinder is ignited so that the expansion strokes of the cylinders do not overlap with each other. The integrated interval of the integrated value is set to be shorter than the length from the time of ignition of the cylinder performing misfire determination to the time of ignition of the cylinder to be ignited next, and the integrated interval when the internal combustion engine is less than a predetermined number of revolutions, Predetermined times Because it is intended to set shorter than the integration interval when the number of above, the misfire of the internal combustion engine 4-stroke, are detected by use of an integrated value obtained by integrating with the appropriate integrating period, a misfire of the internal combustion engine The risk of erroneous detection can be reduced.

Further, according to the internal combustion engine misfire detection apparatus according to the first aspect of the present invention, it is possible to suppress stroke of another cylinder do not depend on the combustion, the variation of the rotational speed parameter due to the influence of such inertia or friction In addition, misfire can be reliably detected at both low and high engine speeds.

Further, according to the internal combustion engine misfire detection apparatus according to a second aspect of the present invention, calculation output unit for the integrating period is for setting the individual length for each cylinder, internal combustion engine comprising more than two cylinders Even when the cylinders have different combustion conditions, misfire of the internal combustion engine can be accurately detected.

Further, according to the third internal combustion engine misfire detection apparatus according to aspect of the present invention, calculation output unit, the integrating period when the internal combustion engine is lower than a predetermined rotational speed, the end from the start of the expansion stroke of the internal combustion engine The length of time until the hour is set, and the integration interval when the internal combustion engine is equal to or higher than the predetermined number of revolutions is set to the length from the start of the expansion stroke of the internal combustion engine to the time immediately before the ignition of the next cylinder to be ignited Therefore, when the engine is running at a low speed, an integration interval that excludes the exhaust stroke and beyond is set to suppress the variation in the rotational speed parameter due to friction and other factors that do not depend on combustion. By setting an integration interval up to immediately before the ignition of the next cylinder to be ignited and suppressing variations in rotational speed parameters due to the influence of inertial force, etc. that do not depend on combustion, normal ignition and misfire And in It is possible to increase the S / N ratio of the difference.

Further, according to the internal combustion engine misfire detection apparatus according to the fourth aspect of the present invention, the calculation unit includes a filter that removes a high-frequency component included in the electrical signal indicating the rotation speed parameter, and the high-frequency component is removed by the filter. In addition to calculating the reference value of the rotational speed parameter indicated by the electrical signal, the deviation between the reference value and the rotational speed parameter indicated by the electrical signal from which the high frequency component has been removed by the filter is calculated. Therefore, it is possible to remove noise contained in the electrical signal indicating the above, and to calculate the integrated value with high accuracy.

FIG. 1 is a block diagram illustrating a configuration of an internal combustion engine misfire detection apparatus according to an embodiment of the present invention. FIG. 2 is a flowchart showing the flow of determination parameter calculation processing in the embodiment of the present invention. FIG. 3 is a diagram showing a specific transition of each stroke and crank angular velocity for each cylinder when the determination parameter is calculated in the determination parameter calculation processing according to the embodiment of the present invention. FIG. 4 is a flowchart showing the flow of misfire determination processing in the embodiment of the present invention.

  Hereinafter, an internal combustion engine misfire detection apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings as appropriate.

  First, the configuration of the internal combustion engine misfire detection apparatus in the present embodiment will be described in detail with reference to FIG.

  FIG. 1 is a block diagram illustrating a configuration of an internal combustion engine misfire detection apparatus according to an embodiment of the present invention.

  As shown in FIG. 1, the internal combustion engine misfire detection device 1 according to the present embodiment is configured by an electronic control unit such as an ECU (Electronic Control Unit), which includes a plurality of cylinders (not shown) and each cylinder. After completion of the expansion stroke, the other cylinders are ignited (the expansion strokes of the cylinders do not overlap with each other). As a 4-stroke internal combustion engine, typically a motorcycle equipped with a drive wheel, a main clutch and a transmission, etc. It is mounted on a saddle-ride type vehicle. Such an engine is typically an engine having two or three cylinders and performing equal combustion with the same ignition interval between cylinders or non-uniform combustion with different ignition intervals between cylinders. One throttle valve and intake pressure sensor 21 (not shown) are provided on the upstream side of each cylinder.

  The internal combustion engine misfire detection device 1 includes a crank angular velocity calculation unit 2, a determination threshold value search unit 3, a determination parameter calculation unit 4, and a misfire determination unit 5.

  The crank angular speed calculation unit 2 performs cranking as a rotational speed parameter for each predetermined crank angle based on an electrical signal corresponding to an engine crank angle (a rotation angle of a crankshaft not shown) input from the crank sensor 22. The shaft angular velocity (hereinafter referred to as “crank angular velocity”) is calculated. The crank angular velocity calculation unit 2 outputs an electrical signal indicating the crank angular velocity calculated as described above to the determination parameter calculation unit 4.

  The determination threshold value search unit 3 receives an electric signal corresponding to the crank angle of the engine inputted from the crank sensor 22 and an intake air between a throttle valve (not shown) inputted from an intake pressure sensor 21 provided for each cylinder and the engine. Based on the electric signal corresponding to the pressure, a determination threshold value corresponding to the engine load state obtained from the engine speed and the intake pressure is calculated for each cylinder, so that the determination threshold value is set differently for each cylinder. Specifically, the determination threshold value search unit 3 increases the determination threshold value as the engine load state increases. For example, the determination threshold value search unit 3 reads table data stored in a ROM (not shown) in which the relationship between the determination threshold value, the engine speed, and the intake pressure is defined in advance for each cylinder, and stores the table data in the read table data. The determination threshold value is calculated by applying the engine speed and the intake pressure calculated from the angle for each cylinder. The determination threshold value search unit 3 outputs an electrical signal indicating the determination threshold value calculated in this way to the misfire determination unit 5. It should be noted that the engine load state is not limited to the case of obtaining the engine speed and the intake pressure, but may be obtained from the engine speed and the throttle valve opening.

  The determination parameter calculation unit 4 includes a filter (not shown) that removes a high-frequency component included in the electrical signal indicating the crank angular velocity input from the crank angular velocity calculation unit 2. Such a filter is typically a digital filter such as a moving average filter.

  The determination parameter calculation unit 4 calculates a determination parameter for determining misfire by executing a determination parameter calculation process described later.

  Specifically, the determination parameter calculation unit 4 is input from the crank sensor 22 and an electric signal corresponding to the intake pressure between the throttle valve and the engine input from the intake pressure sensor 21 provided for each cylinder. The end of the compression stroke of each cylinder (hereinafter referred to as “compression TDC stage”) is detected based on an electrical signal corresponding to the crank angle of the engine. The determination parameter calculation unit 4 detects the end of the integration period of each cylinder (hereinafter referred to as “integration end stage”) based on the electrical signal corresponding to the crank angle of the engine input from the crank sensor 22.

  The determination parameter calculation unit 4 holds the crank angular velocity of the compression TDC stage among the crank angular velocities indicated by the electric signal from which the high-frequency component has been removed by the filter as a reference angular velocity as a reference value.

  The determination parameter calculation unit 4 subtracts the stored reference angular velocity from the crank angular velocity indicated by the electrical signal from which the high frequency component has been removed by the filter from the time of detection of the compression TDC stage to the detection of the integration interval end stage, and obtains the crank angular velocity. A relative crank angular speed as a deviation from the reference angular speed is calculated, and the calculated relative crank angular speed is integrated for each integration section to obtain an integrated value as a determination parameter. Such an integration interval is set according to the engine speed determined from the engine crank angle indicated by the electric signal input from the crank sensor 22. The determination parameter calculation unit 4 outputs an electrical signal indicating the calculated integrated value to the misfire determination unit 5.

  The misfire determination unit 5 determines misfire by executing a misfire determination process described later. Specifically, the misfire determination unit 5 includes the integrated value of the relative crank angular speed indicated by the electric signal input from the determination parameter calculation unit 4 and the determination threshold indicated by the electric signal input from the determination threshold value search unit 3. In comparison, it is determined that misfire has occurred when the integrated value is less than or equal to the determination threshold. When the misfire determination unit 5 determines that a misfire has occurred, the misfire determination unit 5 displays the notification on the display device 24 and notifies the user.

  The internal combustion engine misfire detection apparatus 1 having the above-described configuration performs the following determination parameter calculation process and misfire determination process. Hereinafter, each process will be described in detail with reference to FIGS.

<Determination parameter calculation processing>
In the internal combustion engine misfire detection apparatus 1 having the above-described configuration, a determination parameter calculation process for calculating a determination parameter for determining misfire is executed. Hereinafter, with reference to FIG. 2 and FIG. 3, the specific flow of the determination parameter calculation processing in the present embodiment will be described in detail.

  FIG. 2 is a flowchart showing the flow of determination parameter calculation processing in the embodiment of the present invention. FIG. 3 is a diagram showing a specific transition of each stroke and crank angular velocity for each cylinder when the determination parameter is calculated in the determination parameter calculation processing according to the embodiment of the present invention.

  2 and 3, a case where the determination parameter calculation process is executed is described as an example for a four-stroke engine having two cylinders of # 1 cylinder and # 2 cylinder and performing non-uniform combustion. At this time, if the cylinder performing the misfire determination is the # 1 cylinder, the cylinder to be lit next is the # 2 cylinder, and if the cylinder performing the misfire determination is the # 2 cylinder, the cylinder to be lit next is # One cylinder. FIG. 3 shows, as an example, the transition of the crank angular speed when misfire occurs in the # 2 cylinder. In this embodiment, FIGS. 2 and 3 show the case where the determination parameter calculation process is executed in an engine having two cylinders. However, the determination parameter calculation process is performed in a single cylinder engine or an engine having three or more cylinders. May be executed.

  In the engine according to this embodiment, after the expansion strokes of the respective cylinders are finished, the other cylinders are ignited (the expansion strokes of the cylinders do not overlap), and as shown in FIG. In each of these, four cycles of an expansion stroke, an exhaust stroke, an intake stroke, and a compression stroke are repeated. Specifically, as shown in FIG. 3, the interval during which the crankshaft rotates from 0 degrees to 180 degrees is the expansion stroke of the # 1 cylinder, and the interval during which the crankshaft rotates from 180 degrees to 360 degrees is # 1 cylinder exhaust stroke, the interval during which the crankshaft rotates from 360 degrees to 540 degrees is the # 1 cylinder intake stroke, and the interval during which the crankshaft rotates from 540 degrees to 720 degrees is the # 1 cylinder The compression process. Further, the interval during which the crankshaft rotates from X1 degrees to X2 degrees after the end of the expansion stroke of the # 1 cylinder is the expansion stroke of the # 2 cylinder.

  At this time, as shown in FIG. 3, as the crankshaft rotates from the crank angle X1 at the time of ignition of the # 2 cylinder, the crank angular speed in a normal state in which no misfire occurs (hereinafter referred to as “normal crank angular speed”). And a crank angular speed (hereinafter referred to as “crank angular speed during misfire”) L2 in a state where misfire has occurred. The normal crank angular speed L1 peaks at the expansion stroke end stage at the end of the expansion stroke of the # 2 cylinder whose crankshaft has rotated to the crank angle X2. The misfire misfire crank angular speed L2 gradually decreases as the crankshaft rotates from the crank angle X1. Thus, in the expansion stroke end stage of the # 2 cylinder, the difference between the normal crank angular speed L1 and the misfire crank angular speed L2 becomes the largest.

  On the other hand, while the crankshaft rotates from the crank angle X2 to the crank angle 720 which is the ignition time of the # 1 cylinder to be ignited next, compared with the crankshaft rotating from the crank angle X1 to the crank angle X2, The variation in the normal crank angular speed L1 increases due to the influence of inertial force, friction or the stroke of the # 1 cylinder. The # 1 cylinder shows the same tendency as the # 2 cylinder.

  In the present embodiment, the integrated section of the relative crank angular speed is set in consideration of the above characteristics of the crank angular speed.

  The flowchart shown in FIG. 2 starts when a vehicle such as a straddle-type vehicle is activated and the internal combustion engine misfire detection device 1 is operated, and the determination parameter calculation process proceeds to step S1. Such determination parameter calculation processing is repeatedly executed while the vehicle is activated and the internal combustion engine misfire detection device 1 is operating.

  Here, the determination parameter calculation unit 4 holds the crank angular velocity of the compression TDC stage as the reference angular velocity L before starting the process of step S1.

  In the process of step S1, the determination parameter calculation unit 4 is input from the crank sensor 22 and the electric signal input from the intake pressure sensor 21 for detecting the intake pressure between the throttle valve of the # 1 cylinder and the engine. It is determined whether or not the compression TDC stage of the # 1 cylinder is based on an electrical signal corresponding to the crank angle of the engine. As a result of the determination, if it is not the compression TDC stage of the # 1 cylinder, the determination parameter calculation unit 4 advances the determination parameter calculation process to the process of step S2. On the other hand, in the case of the # 1 cylinder compression TDC stage, the determination parameter calculation unit 4 advances the determination parameter calculation process to the process of step S14.

  Specifically, the determination parameter calculation unit 4 receives the electric signal input from the crank sensor 22 when the intake pressure indicated by the electric signal input from the intake pressure sensor 21 provided in the # 1 cylinder is negative. Thus, when it is detected that the top dead center has been reached before the crank angle reaches 360 degrees, it is determined that it is the # 1 cylinder compression TDC stage, and otherwise, the # 1 cylinder compression TDC stage is determined. Judge that there is no.

  In the process of step S2, the determination parameter calculation unit 4 receives the electric signal input from the intake pressure sensor 21 for detecting the intake pressure between the throttle valve of the # 2 cylinder and the engine, and the crank sensor 22. Based on the electrical signal corresponding to the crank angle of the engine, it is determined whether or not it is a # 2 cylinder compression TDC stage. As a result of the determination, if it is not the # 2 cylinder compression TDC stage, the determination parameter calculation unit 4 advances the determination parameter calculation process to the process of step S3. On the other hand, in the case of the # 2 cylinder compression TDC stage, the determination parameter calculation unit 4 advances the determination parameter calculation process to the process of step S14.

  Specifically, the determination parameter calculation unit 4 receives the electric signal input from the crank sensor 22 when the intake pressure indicated by the electric signal input from the intake pressure sensor 21 provided in the # 2 cylinder is negative. Therefore, when it is detected that the top dead center has been reached before the crank angle reaches 360 degrees, it is determined that the compression TDC stage is the # 2 cylinder, and otherwise, the # 2 cylinder compression TDC stage is determined. Judge that there is no.

  In the process of step S3, the determination parameter calculation unit 4 removes the high frequency component included in the electric signal indicating the crank angular velocity input from the crank angular velocity calculation unit 2 by the filter, and indicates the electric signal from which the high frequency component has been removed. The relative angular velocity (relative crank angular velocity = current determining angular velocity−reference angular velocity L) is calculated by subtracting the reference angular velocity L from the crank angular velocity as the current determining angular velocity, and the integrated value of the relative crank angular velocity accumulated up to the previous time is calculated. An integrated value as a determination parameter (determination parameter = previous determination parameter value + relative crank angular velocity) is calculated by adding and integrating the relative crank angular velocity calculated this time to a certain determination parameter previous value.

  Here, the electrical signal indicating the crank angular velocity output from the crank angular velocity calculating unit 2 includes random noise due to various vibrations or variations in computation. Such noise can be removed by removing a high-frequency component contained in the electric signal output from the crank angular velocity calculation unit 2 with a filter. As shown in FIG. 3, the relative crank angular speed when no misfire has occurred is a positive value because the normal crank angular speed L1 is greater than the reference angular speed L. On the other hand, the relative crank angular speed when misfire occurs is a negative value because the misfire-time crank angular speed L2 is smaller than the reference angular speed L.

  Thereby, the process of step S3 is completed, and the determination parameter calculation process proceeds to the process of step S4.

  In the process of step S4, the determination parameter calculation unit 4 determines whether or not the engine speed is equal to or higher than the # 1 cylinder high rotation determination value. As a result of the determination, if the engine speed is equal to or higher than the # 1 cylinder high rotation determination value, the determination parameter calculation unit 4 advances the determination parameter calculation process to the process of step S5. On the other hand, when the engine speed is less than the # 1 cylinder high rotation determination value, the determination parameter calculation unit 4 advances the determination parameter calculation process to the process of step S6. As the high rotation determination value, for example, a rotation speed of 8000 rpm at the maximum torque is set in advance.

  In the process of step S5, the determination parameter calculation unit 4 sets a high-rotation stage when the integration of # 1 cylinder ends (hereinafter referred to as “# 1 cylinder integration completion stage”). Such a high rotation stage is immediately before ignition of the # 2 cylinder that is ignited next to the # 1 cylinder. In the case of FIG. 3, the high rotation stage is immediately before the crank angle X. Thereby, the process of step S5 is completed, and the determination parameter calculation process proceeds to the process of step S7.

  In the process of step S6, the determination parameter calculation unit 4 sets the low / medium rotation stage as the # 1 cylinder integration end stage. Such a stage for low / medium rotation is at the end of the expansion stroke of the # 1 cylinder. In the case of FIG. 3, the low / medium rotation stage has a crank angle 180 at the end of the expansion stroke of the # 1 cylinder. Thereby, the process of step S6 is completed, and the determination parameter calculation process proceeds to the process of step S7.

  In the process of step S7, the determination parameter calculation unit 4 determines whether or not the engine speed is equal to or higher than the # 2 cylinder high rotation determination value. As a result of the determination, if the engine speed is equal to or greater than the # 2 cylinder high rotation determination value, the determination parameter calculation unit 4 advances the determination parameter calculation process to the process of step S8. On the other hand, if the engine speed is less than the # 2 cylinder high rotation determination value, the determination parameter calculation unit 4 advances the determination parameter calculation process to step S9.

  In the process of step S8, the determination parameter calculation unit 4 ignites the # 1 cylinder that ignites next to the # 2 cylinder at the end of the integration of the # 2 cylinder (hereinafter referred to as “# 2 cylinder integration end stage”). Set the stage for high rotation just before the hour. In the case of FIG. 3, the high rotation stage is immediately before the crank angle 720. Thereby, the process of step S8 is completed, and the determination parameter calculation process proceeds to the process of step S10.

  In the process of step S9, the determination parameter calculation unit 4 sets a low / medium rotation stage at the end of the expansion stroke of the # 2 cylinder as the # 2 cylinder integration end stage. In the case of FIG. 3, the low / medium rotation stage is at the crank angle X2 at the end of the expansion stroke of the # 2 cylinder. Thereby, the process of step S9 is completed, and the determination parameter calculation process proceeds to the process of step S10.

  In the process of step S10, the determination parameter calculation unit 4 determines whether it is the # 1 cylinder integration end stage. As a result of the determination, in the case of the # 1 cylinder integration end stage, the determination parameter calculation unit 4 advances the determination parameter calculation process to the process of step S11. On the other hand, if it is not the # 1 cylinder integration end stage, the determination parameter calculation unit 4 advances the determination parameter calculation process to the process of step S12.

  Specifically, when the determination parameter calculation unit 4 detects that the crank angle has reached X1 degrees from the electric signal input from the crank sensor 22 when the high rotation stage is set in step S5. Is determined to be the # 1 cylinder integration end stage, and otherwise it is determined not to be the # 1 cylinder integration end stage. In addition, when the determination parameter calculation unit 4 detects that the crank angle has reached 180 degrees from the electrical signal input from the crank sensor 22 when the low / medium rotation stage is set in step S6, It is determined that it is the # 1 cylinder integration end stage, and it is determined that it is not the # 1 cylinder integration end stage.

  In the process of step S <b> 11, the determination parameter calculation unit 4 outputs the integrated value as the determination parameter for the # 1 cylinder to the misfire determination unit 5.

  Specifically, when the high rotation stage is set in step S5, the determination parameter calculation unit 4 is the # 1 cylinder compression TDC stage (# 1 cylinder expansion) at the crank angle 0 when the # 1 cylinder is ignited. The integrated value of the relative crank angular velocity integrated in the integration interval from the start of the stroke) to the # 1 cylinder integration end stage of the crank angle X1 is output to the misfire determination unit 5. In addition, when the low / medium rotation stage is set in step S6, the determination parameter calculation unit 4 uses the # 1 cylinder compression TDC stage (the expansion stroke of the # 1 cylinder) at the crank angle 0 when the # 1 cylinder is ignited. The integrated value of the relative crank angular speed integrated in the integration section from the start) to the # 1 cylinder integration end stage of the crank angle 180 is output to the misfire determination unit 5.

  Thereby, the process of step S11 is completed and the determination parameter calculation process ends.

  In the process of step S12, the determination parameter calculation unit 4 determines whether it is the # 2 cylinder integration end stage. As a result of the determination, in the case of the # 2 cylinder integration end stage, the determination parameter calculation unit 4 advances the determination parameter calculation process to the process of step S13. On the other hand, if it is not the # 2 cylinder integration end stage, the determination parameter calculation unit 4 ends the determination parameter calculation process.

  Specifically, when the determination parameter calculation unit 4 detects that the crank angle has reached 720 degrees from the electrical signal input from the crank sensor 22 when the stage for high rotation is set in step S8. It is determined that it is the # 2 cylinder integration end stage, and the other is determined not to be the # 2 cylinder integration end stage. When the determination parameter calculation unit 4 detects that the crank angle has reached X2 degrees from the electric signal input from the crank sensor 22 when the low / medium rotation stage is set in step S9. It is determined that it is the # 2 cylinder integration end stage, and it is determined that it is not the # 2 cylinder integration end stage.

  In the process of step S <b> 13, the determination parameter calculation unit 4 outputs the integrated value as the determination parameter for the # 2 cylinder to the misfire determination unit 5.

  Specifically, the determination parameter calculation unit 4 sets the # 2 cylinder compression TDC stage (expansion of the # 2 cylinder) at the crank angle X1 at the time of ignition of the # 2 cylinder when the high rotation stage is set in step S8. The integrated value of the relative crank angular velocity accumulated in the accumulation interval from the start of the stroke) to the crank angle 720 is output to the misfire determination unit 5. In addition, when the low / medium rotation stage is set in step S9, the determination parameter calculation unit 4 uses the # 2 cylinder compression TDC stage (the expansion stroke of the # 2 cylinder) at the crank angle X1 when the # 2 cylinder is ignited. The integrated value of the relative crank angular velocity accumulated in the accumulation interval from the start) to the crank angle X2 is output to the misfire determination unit 5.

  Thereby, the process of step S13 is completed and the determination parameter calculation process ends.

  In the process of step S14, the determination parameter calculation unit 4 resets the integrated value as the determination parameter to “0”. Thereby, the process of step S14 is completed and the determination parameter calculation process ends.

  In this way, when the engine performing non-uniform combustion, in which each cylinder is affected in a different manner by the influence of the other cylinders, is set to a separate length for the # 1 and # 2 cylinders. By doing this, it is possible to suppress the influence of the strokes of other cylinders when obtaining the integrated value of the relative crank angular velocity, and to reduce the variation of the integrated value.

  In addition, at the time of high rotation, not only when setting the integration interval from the time of ignition of the cylinder that performs misfire determination to the time immediately before the ignition of the cylinder to be fired next, but from the time of ignition of the cylinder that performs misfire determination to the next time of ignition If it is shorter than the length of the cylinder to be ignited, an arbitrary integration interval can be set. Moreover, not only when setting the integration interval from the compression TDC stage of the cylinder that performs misfire determination to the end of the expansion stroke during low-speed rotation, but any integration interval shorter than the integration interval set during high rotation Can be set.

<Misfire detection process>
In the internal combustion engine misfire detection apparatus 1 having the above-described configuration, misfire determination processing for determining misfire of the internal combustion engine is executed. Hereinafter, the specific flow of the misfire determination process in the present embodiment will be described in detail with reference to FIG.

  FIG. 4 is a flowchart showing the flow of misfire determination processing in the embodiment of the present invention.

  In FIG. 4, a case where the misfire determination process is executed is described as an example for an engine having two cylinders, # 1 cylinder and # 2 cylinder. In this embodiment, FIG. 4 shows a case where the misfire determination process is executed in an engine having two cylinders, but the misfire determination process may be executed in a single cylinder engine or an engine having three or more cylinders. .

  The flowchart shown in FIG. 4 starts when a vehicle such as a straddle-type vehicle is activated and the internal combustion engine misfire detection apparatus 1 is operated, and the misfire determination process proceeds to a process of step S21. Such misfire determination processing is repeatedly executed while the vehicle is activated and the internal combustion engine misfire detection device 1 is operating.

  In the process of step S21, the misfire determination unit 5 determines whether or not it is the expansion stroke end stage of the # 1 cylinder. Specifically, the misfire determination unit 5 determines whether or not the integrated value as the determination parameter for the # 1 cylinder is input from the determination parameter calculation unit 4. As a result of the determination, if it is the expansion stroke end stage of the # 1 cylinder, the misfire determination unit 5 advances the misfire determination process to the process of step S22. On the other hand, if it is not the expansion stroke end stage of the # 1 cylinder, the misfire determination unit 5 advances the misfire determination process to the process of step S24.

  In the processing of step S22, the misfire determination unit 5 indicates that the integrated value as the determination parameter of the # 1 cylinder indicated by the electric signal input from the determination parameter calculation unit 4 is indicated by the electric signal input from the determination threshold value search unit 3 # It is determined whether or not it is equal to or less than a determination threshold value for one cylinder. At this time, the determination threshold value of the # 1 cylinder is set to a larger value as the engine load state is higher. As a result, when the engine load is high, the generated torque by the engine is relatively larger than that during normal combustion, and the integrated value as a determination parameter correlated with the generated torque by the engine also increases. By setting the determination threshold of the # 1 cylinder to be larger as the load state is higher, misfire can be detected with higher accuracy.

  As a result of the determination, if the integrated value as the determination parameter for the # 1 cylinder is equal to or less than the determination threshold value for the # 1 cylinder, the misfire determination unit 5 advances the misfire determination process to the process of step S23. On the other hand, if the integrated value as the determination parameter for the # 1 cylinder is larger than the determination threshold value for the # 1 cylinder, the misfire determination unit 5 advances the misfire determination process to the process of step S27.

  In the process of step S23, the misfire determination unit 5 determines that a misfire has occurred in the # 1 cylinder. Thereby, the process of step S23 is completed and the misfire determination process proceeds to the process of step S27.

  In the process of step S24, the misfire determination unit 5 determines whether or not it is the expansion stroke end stage of the # 2 cylinder. Specifically, the misfire determination unit 5 determines whether or not the integrated value as the determination parameter for the # 2 cylinder is input from the determination parameter calculation unit 4. As a result of the determination, if it is the # 2 cylinder expansion stroke end stage, the misfire determination unit 5 advances the misfire determination process to the process of step S25. On the other hand, if it is not the expansion stroke end stage of the # 2 cylinder, the misfire determination unit 5 advances the misfire determination process to the process of step S27.

  In the process of step S25, the misfire determination unit 5 indicates the integrated value as the # 2 cylinder determination parameter indicated by the electric signal input from the determination parameter calculation unit 4 as indicated by the electric signal input from the determination threshold value search unit 3. It is determined whether or not it is equal to or less than the determination threshold value for two cylinders. At this time, the determination threshold value of the # 2 cylinder is set to a larger value as the engine load state is higher. As a result, when the engine load is high, the generated torque by the engine is relatively larger than that during normal combustion, and the integrated value as a determination parameter correlated with the generated torque by the engine also increases. The misfire can be detected with high accuracy by setting the determination threshold of the # 2 cylinder to be larger as the load state is higher.

  As a result of the determination, if the integrated value as the determination parameter for the # 2 cylinder is equal to or less than the determination threshold value for the # 2 cylinder, the misfire determination unit 5 advances the misfire determination process to the process of step S26. On the other hand, if the integrated value as the determination parameter for the # 2 cylinder is larger than the determination threshold value for the # 2 cylinder, the misfire determination unit 5 advances the misfire determination process to the process of step S27. Thus, by making the determination threshold value compared with the integrated value of # 1 cylinder different from the determination threshold value compared with the integrated value of # 2 cylinder, it is possible to prevent misdetection of misfire of each cylinder having different combustion conditions. Can do.

  In the process of step S26, the misfire determination unit 5 determines that a misfire has occurred in the # 2 cylinder. Thereby, the process of step S26 is completed and the misfire determination process proceeds to the process of step S27.

  In step S27, the misfire determination unit 5 performs count processing for incrementing or decrementing the count value of a counter (not shown). Thereby, the process of step S27 is completed, and the misfire determination process proceeds to the process of step S28.

  In the process of step S28, the misfire determination unit 5 determines whether or not failure notification is necessary based on the count value. As a result of the determination, if a failure notification is necessary, the misfire determination unit 5 advances the misfire determination process to the process of step S29. Specifically, the misfire determination unit 5 determines that the failure notification is necessary when the count value reaches a predetermined value. On the other hand, when the failure notification is unnecessary, the misfire determination unit 5 advances the misfire determination process to the process of step S30. Specifically, the misfire determination unit 5 determines that the failure notification is unnecessary when the count value does not reach a predetermined value.

  In the process of step S29, the misfire determination unit 5 turns on the display device 24 to notify the occurrence of misfire. Thereby, the process of step S29 is completed and a misfire determination process is complete | finished.

  In the process of step S30, the misfire determination unit 5 keeps the display device 24 OFF and does not notify the occurrence of misfire. Thereby, the process of step S30 is completed and a misfire determination process is complete | finished.

  In the internal combustion engine misfire detection apparatus in the present embodiment as described above, the integrated section of the integrated value of the deviation between the reference value of the rotational speed parameter corresponding to the rotational speed of the internal combustion engine and the rotational speed parameter is set to the rotational speed of the internal combustion engine. Therefore, the risk of misdetecting misfire of the internal combustion engine can be reduced by detecting the misfire of the four-stroke internal combustion engine using the integrated value accumulated in an appropriate integration interval. .

  Further, in the internal combustion engine misfire detection apparatus according to the present embodiment, in the internal combustion engine that includes a plurality of cylinders and in which each cylinder is ignited so that the expansion strokes of the cylinders do not overlap with each other, the internal combustion engine has a predetermined rotation speed or higher. Is set to be shorter than the length from the time of ignition of the cylinder performing the misfire determination to the time of ignition of the next cylinder to be ignited, and the integration interval when the internal combustion engine is less than the predetermined rotational speed is set to a predetermined value. Because it is set to be shorter than the integration interval when the number of revolutions is greater than or equal to the number of revolutions, it is possible to suppress variations in rotational speed parameters due to the effects of the stroke, inertial force, friction, etc. of other cylinders that do not depend on combustion. In addition, misfire can be reliably detected at both low and high engine speeds.

  Further, in the internal combustion engine misfire detection apparatus according to the present embodiment, in the internal combustion engine that includes a plurality of cylinders and in which each cylinder is ignited so that the expansion strokes of the cylinders do not overlap with each other, the integration interval is set for each cylinder individually. Therefore, even if the combustion state of each cylinder of the internal combustion engine having two or more cylinders is different, misfire of the internal combustion engine can be accurately detected.

  Further, in the internal combustion engine misfire detection apparatus according to the present embodiment, in the internal combustion engine that includes a plurality of cylinders and in which each cylinder is ignited so that the expansion strokes of the cylinders do not overlap, the internal combustion engine is less than a predetermined number of revolutions. Is set to the length from the start to the end of the expansion stroke of the internal combustion engine, and the integration interval when the internal combustion engine is equal to or higher than the predetermined number of rotations is determined from the start of the expansion stroke of the internal combustion engine to the next. This is set to the length of the cylinder that ignites immediately before ignition, so when the engine is running at a low speed, an integration interval that excludes the exhaust stroke and beyond is set, and the rotational speed parameter is influenced by friction and other factors that do not depend on combustion. In the case of high engine rotation, an accumulation interval is set up to the cylinder immediately before ignition after the expansion stroke and immediately before ignition. By suppressing the causing variations in the meter, it is possible to increase the normal S / N ratio of the deviation in the time of misfire and ignition.

  In the internal combustion engine misfire detection apparatus according to the present embodiment, a high-frequency component included in the electrical signal indicating the rotation speed parameter is removed by a filter to calculate a reference value for the rotation speed parameter, and the reference value and the filter are used to calculate the high-frequency component. Therefore, the noise included in the electrical signal indicating the rotational speed parameter can be removed, and the integrated value can be calculated accurately. it can.

  In the present invention, the type, shape, arrangement, number, etc. of the members are not limited to the above-described embodiments, and the constituent elements thereof are appropriately replaced with those having the same operational effects, etc. Of course, it can be appropriately changed within the range.

  Specifically, in the above-described embodiment, the determination threshold value corresponding to the engine load state is set, but a determination threshold value as a fixed value may be set in advance regardless of the engine load state.

  Further, in the above embodiment, when misfire is detected, it is displayed and notified on the display device. However, misfire may be notified by voice, sound, or light, and in addition to or instead of notifying misfire, When misfire is detected, control for changing the operating state of the engine may be performed.

  In the above embodiment, the crank angular velocity is used when calculating the integrated value to be compared with the determination threshold. However, the present invention is not limited to this, and any parameter having a correlation with the crank angular velocity can be used.

  As described above, in the present invention, the risk of misdetecting misfire of the internal combustion engine can be reduced by detecting the misfire of the 4-stroke internal combustion engine using the accumulated value obtained by accumulating in an appropriate accumulation interval. The internal combustion engine misfire detection device can be provided, and it is expected that it can be widely applied to the internal combustion engine misfire detection device of a vehicle such as a motorcycle because of its universality.

1 ... ECU
DESCRIPTION OF SYMBOLS 2 ... Crank angular velocity calculation part 3 ... Determination threshold value search part 4 ... Determination parameter calculation part 5 ... Misfire determination part 21 ... Intake pressure sensor 22 ... Crank sensor 24 ... Display apparatus

Claims (4)

In an internal combustion engine misfire detection apparatus for detecting misfire of a 4-stroke internal combustion engine,
A rotation speed parameter corresponding to the rotation speed of the internal combustion engine is calculated for each predetermined crank angle, a reference value of the rotation speed parameter is calculated, a deviation between the reference value and the rotation speed parameter is calculated, and A calculation unit for calculating an integrated value of the deviation;
A determination unit that performs misfire determination based on the integrated value;
With
The internal combustion engine
With multiple cylinders, each cylinder is ignited so that the expansion strokes of each cylinder do not overlap,
The calculation unit includes:
An integration interval of the integrated value when the internal combustion engine is equal to or higher than a predetermined number of revolutions is set to be shorter than a length from the time of ignition of a cylinder performing misfire determination to the time of ignition of a cylinder to be ignited next; Setting the integration interval when the engine is less than the predetermined rotation speed to be shorter than the integration interval when the engine is greater than or equal to the predetermined rotation speed;
An internal combustion engine misfire detection device characterized by the above. Before Symbol calculating unit,
Setting the integration interval to an individual length for each cylinder;
The internal combustion engine misfire detection apparatus according to claim 1 . Before Symbol calculating unit,
Wherein said integrating period when the internal combustion engine is lower than the predetermined rotational speed, the set to the length of from the start to the end of the expansion stroke of the internal combustion engine, wherein when the internal combustion engine is of the more than a predetermined rotational speed Is set to a length from the start of the expansion stroke of the internal combustion engine to just before the ignition of the next cylinder to be ignited,
The internal combustion engine misfire detection apparatus according to claim 1 or 2 , wherein the internal combustion engine misfire detection apparatus is provided. The calculation unit includes:
A filter that removes a high-frequency component included in the electrical signal indicating the rotational speed parameter; and calculating the reference value of the rotational speed parameter indicated by the electrical signal from which the high-frequency component has been removed by the filter, and the reference value Calculating the deviation of the rotational speed parameter indicated by the electrical signal from which the high frequency component has been removed by the filter;
The internal combustion engine misfire detection device according to any one of claims 1 to 3 .

Images