JP6484299B2 - Internal combustion engine misfire detection device - Google Patents

Description

  The present invention includes a plurality of cylinders, and each cylinder is ignited so that the expansion strokes of the cylinders do not overlap. For example, an internal combustion engine misfire detection that detects misfire of a 2-stroke or 3-cylinder 4-stroke internal combustion engine Relates to the device.

  In an internal combustion engine, for example, an engine having a plurality of cylinders, output is produced 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. For this reason, for example, in a 2-cylinder or 3-cylinder engine mounted on a motorcycle or the like, the integration section is a section during which the crankshaft rotates 360 degrees or 240 degrees and becomes a relatively long section. Under the influence of inertial force or friction, there is a possibility that the variation of the integrated value becomes large. In this case, the risk of misdetecting misfire increases.

  The present invention has been made through the above-described studies. The misfire of a four-stroke internal combustion engine in which ignition of other cylinders is performed after completion of the expansion stroke of each of a plurality of cylinders is integrated in an appropriate integration interval. It is an object of the present invention to provide an internal combustion engine misfire detection device capable of reducing the risk of erroneously detecting misfire of an internal combustion engine by detecting using the integrated value.

To achieve the above object, according to the first aspect of the present invention, there is provided a two-cylinder or three-cylinder four-stroke, which comprises a plurality of cylinders and in which each cylinder is ignited so that the expansion strokes of the cylinders do not overlap. In the internal combustion engine misfire detection apparatus for detecting misfire of the internal combustion engine, a rotational speed parameter corresponding to the rotational speed of the internal combustion engine is calculated for each predetermined crank angle, a reference value of the rotational speed parameter is calculated, and the reference A calculation unit that calculates a deviation between the value and the rotation speed parameter, and that calculates an integrated value of the deviation, and a determination unit that performs misfire determination based on the integrated value, the calculation unit including a misfire determination An integration interval of the integrated value of the length from the start to the end of the expansion stroke of the cylinder to be performed is set, and the integrated value is calculated between the end of the integration interval and the ignition of the next cylinder. An internal combustion engine misfire detection apparatus for setting a non intervals.

In addition to the first aspect, the present invention includes a filter that removes a high-frequency component included in the electrical signal indicating the rotation speed parameter, and the calculation unit indicates the electrical signal from which the high-frequency component has been removed by the filter. to calculate the reference value of the rotational speed parameter, said reference value, and the rotational speed parameter indicative of electric signal removing high frequency components by the filter, second to calculate the deviation of the phase To do.

The present invention, in addition to the first or second aspect, the internal combustion engine, the third aspect to carry out ignition at different intervals unequal combustion between the cylinders.

The internal combustion engine misfire detection apparatus according to the first aspect of the present invention includes a two-cylinder or three-cylinder four-stroke 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. In the internal combustion engine misfire detection apparatus for detecting misfire of the engine, a rotational speed parameter corresponding to the rotational speed of the internal combustion engine is calculated for each predetermined crank angle, a reference value of the rotational speed parameter is calculated, and the reference value and The calculation unit includes a calculation unit that calculates a deviation from the rotation speed parameter and calculates an integrated value of the deviation, and a determination unit that performs misfire determination based on the integrated value, and the calculation unit performs misfire determination. The integration interval of the integrated value of the length from the start to the end of the expansion stroke of the cylinder is set, and the integrated value is calculated between the end of the integration interval and the ignition of the next cylinder. Because it is intended to set the non interval, the integrated value after the expansion stroke ends of each cylinder ignition other cylinders misfires of the internal combustion engine of 4 strokes performed, and integrated with the appropriate integrating period provided with a plurality of cylinders By using and detecting, the risk of misdetecting misfire of the internal combustion engine can be reduced.

Further, according to the internal combustion engine misfire detection apparatus according to the first aspect of the present invention, the calculation unit sets the integration interval of the length from the start to the end of the expansion stroke of the internal combustion engine. A sufficient difference between the integrated value at normal time and the integrated value at misfire can be obtained sufficiently, and the variation in the integrated value can be reduced.

Further, according to the internal combustion engine misfire detection apparatus according to the second aspect of the present invention, the calculation unit includes the filter that removes the high-frequency component of the rotation speed parameter, and the rotation with the high-frequency component removed by the reference value and the filter. Since the deviation from the speed parameter is calculated, noise included in the electric signal indicating the rotation speed parameter can be removed, and the integrated value can be calculated with high accuracy.

Moreover, according to the internal combustion engine misfire detection apparatus according to the third aspect of the present invention, the internal combustion engine performs unequal interval combustion with different ignition intervals between the cylinders. The risk of false detection of misfire can be reduced.

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 diagram showing a specific transition of the crank angular velocity in the case where misfire occurs when the determination parameter is calculated in the determination parameter calculation processing according to the embodiment of the present invention and in the case where no misfire occurs. FIG. 5 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 that are not shown, Typically mounted in a straddle-type vehicle such as a motorcycle including an engine, a drive wheel, a main clutch, and a transmission as a 4-stroke internal combustion engine in which each cylinder is ignited so that the expansion strokes do not overlap. . Such an engine is typically an engine having two or three cylinders, or an engine that performs non-uniform combustion with different ignition intervals between the 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 is based on the electrical signal corresponding to the crank angle of the engine input from the crank sensor 22 and at the end of the expansion stroke, which is the end of the integration period (hereinafter referred to as “expansion stroke end stage”). Is detected.

  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 held 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 time of detection of the expansion stroke end stage to obtain 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 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. 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 to FIG. 4, a 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. FIG. 4 is a diagram showing a specific transition of the crank angular velocity in the case where misfire occurs when the determination parameter is calculated in the determination parameter calculation processing according to the embodiment of the present invention and in the case where no misfire occurs.

  2 to 4, the determination parameter calculation process is executed for a four-stroke engine having two cylinders # 1 and # 2 and in which other cylinders are ignited after the expansion stroke of each cylinder is completed. A case will be described as an example. 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. 4 shows changes in the crank angular speed during normal operation and misfire in the # 2 cylinder. The # 1 cylinder also has the same tendency as in FIG. 4, but the interval between the crank angle X2 and the crank angle X3 in the # 1 cylinder is shorter than that in FIG. FIG. 4 shows the transition of the crank angular speed when the engine speed is 3,000 rpm and the intake air pressure is 38.4 kPa as an example.

  In the engine according to the present embodiment, as shown in FIG. 3, the # 2 cylinder is ignited after the expansion stroke of the # 1 cylinder is completed, and the expansion stroke, the exhaust stroke, and the intake stroke are respectively performed in the # 1 cylinder and the # 2 cylinder. And 4 cycles of the compression stroke. 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. 4, as the crankshaft rotates from the crank angle X1 when the # 2 cylinder is ignited, 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 X3 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 also shows the same tendency as the # 2 cylinder shown in FIG.

  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 a reference angular velocity 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 S8.

  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. When it is detected that the top dead center has been reached before rotating 360 degrees from the crank angle indicated by, it is determined that the compression TDC stage is the # 1 cylinder. Otherwise, the compression TDC stage of the # 1 cylinder is determined. It is determined that it is not.

  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 S8.

  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. When it is detected that the top dead center has been reached before rotating 360 degrees from the crank angle indicated by, it is determined that it is a # 2 cylinder compression TDC stage, and otherwise, it is a # 2 cylinder compression TDC stage. It is determined that it is not.

  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. Relative crank angular velocity (relative crank angular velocity = current determination angular velocity−reference angular velocity) is calculated by subtracting the reference angular velocity from the crank angular velocity as the current angular velocity for determination. An integrated value (determination parameter = previous determination parameter value + relative crank angular velocity) is calculated as a determination parameter by adding and integrating the relative crank angular velocity calculated this time to the previous parameter 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 high-frequency components with a filter. In addition, 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 it is the expansion stroke end stage of the # 1 cylinder based on the electric signal input from the crank sensor 22. As a result of the determination, in the case of the expansion stroke end stage of the # 1 cylinder, the determination parameter calculation unit 4 advances the determination parameter calculation process to the process of step S5. On the other hand, if it is not the expansion stroke end stage of the # 1 cylinder, the determination parameter calculation unit 4 advances the determination parameter calculation process to the process of step S6.

  Specifically, when the determination parameter calculation unit 4 detects that the engine has rotated 180 degrees from the compression TDC stage of the # 1 cylinder from the crank angle indicated by the electrical signal input from the crank sensor 22, the expansion of the # 1 cylinder is detected. It is determined that it is the stroke end stage, and it is determined that it is not the # 1 cylinder expansion stroke end stage otherwise. The timing at which the # 1 cylinder expansion stroke end stage is determined is when the crankshaft rotates from a crank angle 0 to a crank angle 180, as shown in FIG.

  In the process of step S <b> 5, the determination parameter calculation unit 4 outputs the integrated value as the determination parameter for the # 1 cylinder to the misfire determination unit 5. Thereby, the process of step S5 is completed and the determination parameter calculation process ends.

  In the process of step S <b> 6, the determination parameter calculation unit 4 determines whether or not it is the expansion stroke end stage of the # 2 cylinder based on the electrical signal input from the crank sensor 22. As a result of the determination, in the case of the expansion stroke end stage of the # 2 cylinder, the determination parameter calculation unit 4 advances the determination parameter calculation process to the process of step S7. On the other hand, when it is not the expansion stroke end stage of the # 2 cylinder, the determination parameter calculation unit 4 ends the determination parameter calculation process.

  Specifically, when the determination parameter calculation unit 4 detects that the engine has rotated 180 degrees from the compression TDC stage of the # 2 cylinder from the crank angle indicated by the electrical signal input from the crank sensor 22, the expansion of the # 2 cylinder is detected. It is determined that it is the stroke end stage, and it is determined that it is not the expansion stroke end stage of the # 2 cylinder other than that. The timing at which the # 2 cylinder expansion stroke end stage is determined is when the crankshaft rotates from the crank angle X1 to the crank angle X2, as shown in FIGS.

  In the process of step S <b> 7, the determination parameter calculation unit 4 outputs the # 2 cylinder determination parameter to the misfire determination unit 5. Thereby, the process of step S7 is completed and the determination parameter calculation process ends.

  In this way, in the # 1 cylinder, by integrating the relative crank angular speed in the integration section shown in FIG. 3 from the start of the expansion stroke at the crank angle 0 (during ignition) to the end of the expansion stroke at the crank angle 180, The difference between the normal crank angular speed L1 and the misfiring crank angular speed L2 can be sufficiently obtained, and variations in the normal crank angular speed L1 and misfire crank angular speed L2 can be reduced. Can reduce the risk. Further, in the # 2 cylinder, normal time is obtained by integrating the relative crank angular velocity in the integration section shown in FIG. 3 from the start of the expansion stroke at the crank angle X1 (during ignition) to the end of the expansion stroke at the crank angle X2. The difference between the crank angular speed L1 and the crank angular speed L2 at the time of misfire can be sufficiently obtained, and the variation of the crank angular speed L1 at the normal time and the crank angular speed L2 at the time of misfire can be reduced. Can be reduced.

  In the # 1 cylinder, inertial force, friction or # 2 cylinder is obtained by integrating in the integration interval shown in FIG. 3 from the start of the expansion stroke at the crank angle 0 (during ignition) to the end of the expansion stroke at the crank angle 180. The interval from the crank angle 180 to the crank angle X3, which is an unnecessary integration section that varies due to the influence of the stroke or the like, can be excluded from the integration section, and the variation in the integrated value can be reduced. Further, in the # 2 cylinder, by integrating in the integration interval shown in FIG. 3 from the start of the expansion stroke at the crank angle X1 (at the time of ignition) to the end of the expansion stroke at the crank angle X2, the inertial force, friction or # 1 The interval from the crank angle X2 to the next compression TDC stage of the # 2 cylinder, which is an unnecessary integration section that varies due to the influence of the cylinder stroke, etc., can be excluded from the integration section, and the variation in the integrated value can be reduced. Can do.

  Each cylinder is not limited to setting an integration interval from the time of ignition to the exhaust stroke end stage, but is # 2 cylinder that is the next cylinder to be ignited from the time of ignition of the # 1 cylinder or # 2 cylinder that performs misfire determination Alternatively, if it is before ignition of the # 1 cylinder, an integration interval from before or after the exhaust stroke end stage may be set. Further, in each cylinder, when the variation in the normal crank angular speed L1 is small, or when the difference between the normal crank angular speed and the misfire crank angular speed can be sufficiently obtained, the # 1 cylinder or the # 1 that performs misfire determination An arbitrary integration section shorter than the length from the time of ignition of the two cylinders to the time of ignition of the # 2 cylinder or the # 1 cylinder that is the next cylinder to be ignited may be set.

  In the process of step S8, the determination parameter calculation unit 4 resets the integrated value as the determination parameter to “0”. Thereby, the process of step S8 is completed and the determination parameter calculation process ends.

<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, a specific flow of the misfire determination process in the present embodiment will be described in detail with reference to FIG.

  FIG. 5 is a flowchart showing the flow of misfire determination processing in the embodiment of the present invention.

  In FIG. 5, an example in which a misfire determination process is executed for an engine having two cylinders, # 1 cylinder and # 2 cylinder, will be described.

  The flowchart shown in FIG. 5 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 S11. 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 S11, 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 S12. 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 S14.

  In the process of step S12, the misfire determination unit 5 indicates that the integrated value as the determination parameter of # 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 S13. 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 S17.

  In the process of step S13, the misfire determination unit 5 determines that a misfire has occurred in the # 1 cylinder. Thereby, the process of step S13 is completed and the misfire determination process proceeds to the process of step S17.

  In the process of step S14, 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 expansion stroke end stage of the # 2 cylinder, the misfire determination unit 5 advances the misfire determination process to the process of step S15. 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 S17.

  In the process of step S15, the misfire determination unit 5 indicates that the integrated value as the determination parameter of the # 2 cylinder indicated by the electric signal input from the determination parameter calculation unit 4 is the # 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 S16. 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 S17. 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 S16, the misfire determination unit 5 determines that a misfire has occurred in the # 2 cylinder. Thereby, the process of step S16 is completed and the misfire determination process proceeds to the process of step S17.

  In step S17, 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 S17 is completed and the misfire determination process proceeds to the process of step S18.

  In step S18, 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 S19. 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 S20. 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 S19, the misfire determination unit 5 turns on the display device 24 to notify the occurrence of misfire. Thereby, the process of step S19 is completed and a misfire determination process is complete | finished.

  In the process of step S20, the misfire determination unit 5 keeps the display device 24 OFF and does not notify the occurrence of misfire. Thereby, the process of step S20 is completed and a misfire determination process is complete | finished.

  In the internal combustion engine misfire detection apparatus in the present embodiment described above, the integration interval of the integrated value of the relative crank angular speed 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. Therefore, a misfire of a 4-stroke internal combustion engine having a plurality of cylinders and igniting other cylinders after completion of the expansion stroke of each cylinder is detected using an integrated value integrated in an appropriate integration interval. As a result, the risk of erroneously detecting misfire of the internal combustion engine can be reduced.

  Further, in the internal combustion engine misfire detection apparatus according to the present embodiment, an integration interval from the time of ignition of the cylinder that performs the misfire determination to the time before the ignition of the cylinder that is ignited next is set. It is possible to reduce the variation in the integrated value by excluding the integration of the latter half of the deviation that increases due to the influence of inertial force, friction, etc. from the time of ignition to the time of the ignition of the next cylinder.

  Further, in the internal combustion engine misfire detection device according to the present embodiment, since the integration interval of the length from the start to the end of the expansion stroke of the internal combustion engine is set, the integrated value at the normal time and the integrated value at the misfire time Can be sufficiently obtained, and variation in the integrated value can be reduced.

  In addition, the internal combustion engine misfire detection apparatus according to the present embodiment includes a filter that removes the high-frequency component of the rotational speed parameter, and calculates a deviation between the reference value and the rotational speed parameter from which the high-frequency component has been removed by the filter. Therefore, noise included in the electrical signal indicating the rotation speed parameter can be removed, and the integrated value can be calculated with high accuracy.

  Further, in the internal combustion engine misfire detection apparatus according to the present embodiment, the internal combustion engine performs non-uniform combustion with different ignition intervals between cylinders, and therefore a risk of misdetecting misfire of the internal combustion engine performing non-uniform combustion. Can be reduced.

  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.

  In the above embodiment, the integration is started from the time of ignition of each cylinder. However, the integration may be started after the time of ignition of each cylinder.

  As described above, according to the present invention, an integrated value obtained by integrating the misfire of a 4-stroke internal combustion engine having a plurality of cylinders and igniting the other cylinders after completion of the expansion stroke of each cylinder in an appropriate integration interval. By using it, it is possible to provide an internal combustion engine misfire detection device that can reduce the risk of misdetection of an internal combustion engine misfire, and because of its universal character, the internal combustion engine misfire of a vehicle such as a motorcycle It is expected that it can be widely applied to detection devices.

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 (3)

In an internal combustion engine misfire detection device that includes a plurality of cylinders and detects misfire of a two-cylinder or three-cylinder four-stroke internal combustion engine in which each cylinder is ignited so that the expansion strokes of the cylinders do not overlap with each other,
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 calculation unit includes:
Set the integration interval of the integrated value of the length from the start to the end of the expansion stroke of the cylinder that performs misfire determination, and the integrated value between the end of the integration interval and the ignition of the next cylinder Set the interval not to calculate,
Engine misfire detection apparatus characterized by. 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;
Engine misfire detecting device according to claim 1 Symbol mounting, characterized in that. The internal combustion engine
Performing non-uniform combustion with different ignition intervals between cylinders,
The internal combustion engine misfire detection apparatus according to claim 1 or 2 , wherein the internal combustion engine misfire detection apparatus is provided.

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