JP5853922B2 - vehicle - Google Patents

Description

  The present invention relates to a vehicle equipped with an engine.

  In a vehicle equipped with an engine, it is determined whether or not misfiring has occurred in the engine from engine rotation fluctuations. However, when the vehicle is traveling on a rough road that causes fluctuations in the rotation of the engine, the misfire determination accuracy may deteriorate. For example, Japanese Patent Application Laid-Open No. 2004-11449 (Patent Document 1) addresses such a problem even when it is determined that misfiring has occurred in the engine based on engine rotation fluctuation. A technique for disabling a determination result that a misfire has occurred when it is determined from the pattern that the vehicle is traveling on a rough road is disclosed.

JP 2004-11449 A

  However, Patent Document 1 does not show how the change pattern of the engine rotation fluctuation differs between when traveling on a rough road and when a misfire occurs. May not be properly determined.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to appropriately discriminate between running on a bad road and occurrence of misfire to improve misfire determination accuracy.

  The vehicle according to the present invention includes an engine having a plurality of cylinders and a control device that determines whether or not misfire has occurred in the engine. The control device calculates a fluctuation amount of time required for the rotation axis of the engine to rotate by a predetermined angle as an engine rotation fluctuation amount, and when the rotation fluctuation amount exceeds a positive first predetermined value and the rotation fluctuation amount is If the rotational fluctuation amount during the predetermined period immediately before exceeding the first predetermined value is larger than the second predetermined value equal to or less than zero, it is determined that misfire has occurred.

  Preferably, even when the rotational fluctuation amount exceeds the first predetermined value, the control device causes the vehicle to travel on a rough road when the rotational fluctuation amount during the immediately preceding predetermined period is smaller than the second predetermined value. It is not determined that misfire has occurred.

  Preferably, the control device calculates the rotation fluctuation amount at a predetermined calculation cycle. The rotation fluctuation amount in the immediately preceding predetermined period is the sum or average of a plurality of rotation fluctuation amounts calculated in a plurality of calculation cycles immediately before the rotation fluctuation amount exceeds the first predetermined value.

  Preferably, the plurality of cylinders are ignited in a predetermined order. The control device calculates the rotational fluctuation amount at a calculation cycle corresponding to the ignition timing of the plurality of cylinders, and if the rotational fluctuation amount continuously exceeds the first predetermined value in the same cylinder, the rotational fluctuation during the immediately preceding predetermined period. Regardless of whether or not the amount is greater than the second predetermined value, it is determined that misfiring has occurred in the cylinder whose rotation fluctuation amount has continuously exceeded the first predetermined value.

  ADVANTAGE OF THE INVENTION According to this invention, a bad road driving | running | working and misfire generation can be discriminate | determined appropriately and a misfire determination precision can be improved.

1 is an overall block diagram of a vehicle. It is a figure which shows the structure of an engine. It is a functional block diagram of ECU. It is a figure which shows an example of the calculation timing (calculation cycle) of rotation time T30 and rotation time fluctuation amount (DELTA) T30. It is a figure which shows typically the change pattern of the engine speed Ne during the rough road driving | running | working, rotation time T30, and rotation time fluctuation amount (DELTA) T30. It is a flowchart which shows the process sequence of ECU.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

  FIG. 1 is an overall block diagram of a vehicle 1 according to the present embodiment. The vehicle 1 includes an engine 10, a drive shaft 16, a first motor generator (hereinafter referred to as a first MG) 20, a second motor generator (hereinafter referred to as a second MG) 30, and a power split device 40. , A reduction gear 58, a PCU (Power Control Unit) 60, a battery 70, a drive wheel 80, and an ECU (Electronic Control Unit) 200.

  The vehicle 1 is a hybrid vehicle that travels by driving force output from at least one of the engine 10 and the second MG 30. The vehicle to which the present invention is applicable is not particularly limited to a hybrid vehicle, and may be a vehicle having only an engine as a drive source, for example.

  The power generated by the engine 10 is divided into two paths by the power split device 40. One of the two routes is a route transmitted to the drive wheel 80 via the speed reducer 58, and the other route is a route transmitted to the first MG 20.

  First MG 20 and second MG 30 are, for example, three-phase AC rotating electric machines. First MG 20 and second MG 30 are driven by PCU 60.

  The first MG 20 has a function as a generator that generates power using the power of the engine 10 divided by the power split device 40 and charges the battery 70 via the PCU 60. Further, first MG 20 receives electric power from battery 70 and rotates a crankshaft that is an output shaft of engine 10. Thus, the first MG 20 has a function as a starter for starting the engine 10.

  Second MG 30 has a function as a driving motor that applies driving force to driving wheels 80 using at least one of the electric power stored in battery 70 and the electric power generated by first MG 20. Second MG 30 also has a function as a generator for charging battery 70 via PCU 60 using electric power generated by regenerative braking.

  FIG. 2 is a diagram illustrating a configuration of the engine 10. The engine 10 is, for example, an internal combustion engine such as a gasoline engine or a diesel engine. The engine 10 includes an air cleaner 102, a throttle valve 104, a plurality of cylinders 106, an injector 108 that supplies fuel to each of the plurality of cylinders 106, a spark plug 110, a three-way catalyst 112, a piston 114, a crank It includes a shaft 116, an intake valve 118, an exhaust valve 120, an intake side cam 122, an exhaust side cam 124, and a VVT (Variable Valve Timing) mechanism 126.

  Air is drawn into the engine 10 from the air cleaner 102. The intake air amount is adjusted by the throttle valve 104. The throttle valve 104 is an electronic throttle valve that is driven by a motor.

  Air is mixed with fuel in the cylinder 106 (combustion chamber). Fuel is directly injected into the cylinder 106 from the injector 108. That is, the injection hole of the injector 108 is provided in the cylinder 106. The fuel is injected from the intake side (the side where air is introduced) of the cylinder 106.

  Fuel is injected during the intake stroke. Note that the timing of fuel injection is not limited to the intake stroke. In the present embodiment, the engine 10 will be described as a direct injection engine in which the injection hole of the injector 108 is provided in the cylinder 106. However, in addition to the direct injection injector 108, a port injection injector is provided. May be. Further, only a port injection injector may be provided.

  The air-fuel mixture in the cylinder 106 is ignited by the spark plug 110 and burned. The air-fuel mixture after combustion, that is, the exhaust gas is purified by the three-way catalyst 112 and then discharged outside the vehicle. The piston 114 is pushed down by the combustion of the air-fuel mixture, and the crankshaft 116 rotates.

  An intake valve 118 and an exhaust valve 120 are provided at the top of the cylinder 106. The amount and timing of air introduced into the cylinder 106 are controlled by the intake valve 118. The amount and timing of exhaust gas discharged from the cylinder 106 is controlled by the exhaust valve 120. The intake valve 118 is driven by the intake side cam 122. The exhaust valve 120 is driven by the exhaust side cam 124.

  The intake valve 118 is changed in opening / closing timing (phase) by the VVT mechanism 126. The opening / closing timing of the exhaust valve 120 may be changed.

  In the present embodiment, the opening / closing timing of the intake valve 118 is controlled by rotating a camshaft (not shown) provided with the intake side cam 122 by the VVT mechanism 126. The method for controlling the opening / closing timing is not limited to this. In the present embodiment, VVT mechanism 126 is operated by hydraulic pressure. The VVT mechanism 126 may be provided on the exhaust side cam 124.

  Engine 10 is controlled based on a control signal from ECU 200. The ECU 200 controls the throttle opening, the ignition timing, the fuel injection timing, the fuel injection amount, and the opening / closing timing of the intake valve 118 so that the engine 10 is in a desired operation state.

  ECU 200 receives signals from crank angle sensor 11, cam angle sensor 204, water temperature sensor 206, and air flow meter 208.

  The crank angle sensor 11 outputs a signal representing the rotation angle of the crankshaft 116 (hereinafter also referred to as “crank angle”). The unit of the crank angle is “° CA (Crank Angle)”. Note that the rotational speed of the crankshaft 116 (hereinafter referred to as “engine rotational speed”) Ne is calculated by the ECU 200 using the detection result of the crank angle sensor 11. The cam angle sensor 204 outputs a signal indicating the position of the intake side cam 122. The water temperature sensor 206 outputs a signal indicating the temperature of the cooling water of the engine 10 (hereinafter also referred to as water temperature). The air flow meter 208 outputs a signal indicating the amount of air taken into the engine 10.

  The ECU 200 controls the engine 10 based on signals input from these sensors, a map and a program stored in a ROM (Read Only Memory) 202.

  Returning to FIG. 1, power split device 40 mechanically connects each of the three elements of drive shaft 16 for rotating drive wheel 80, the output shaft of engine 10, and the rotation shaft of first MG 20. The power split device 40 enables transmission of power between the other two elements by using any one of the three elements described above as a reaction force element. The rotation shaft of second MG 30 is connected to drive shaft 16.

  Power split device 40 is a planetary gear mechanism including a sun gear, a pinion gear, a carrier, and a ring gear. The pinion gear meshes with each of the sun gear and the ring gear. The carrier supports the pinion gear so as to be able to rotate and is coupled to the crankshaft of the engine 10. The sun gear is connected to the rotation shaft of the first MG 20. The ring gear is connected to the rotation shaft of second MG 30 and reduction gear 58 via drive shaft 16.

  Reducer 58 transmits the power from power split device 40 and second MG 30 to drive wheels 80. Reducer 58 transmits the reaction force from the road surface received by drive wheels 80 to power split device 40 and second MG 30.

  PCU 60 converts the DC power stored in battery 70 into AC power for driving first MG 20 and second MG 30. PCU 60 includes a converter and an inverter (both not shown) controlled based on a control signal from ECU 200. The converter boosts the voltage of the DC power received from battery 70 and outputs it to the inverter. The inverter converts the DC power output from the converter into AC power and outputs the AC power to first MG 20 and / or second MG 30. Thus, first MG 20 and / or second MG 30 are driven using the electric power stored in battery 70. The inverter converts AC power generated by the first MG 20 and / or the second MG 30 into DC power and outputs the DC power to the converter. The converter steps down the voltage of the DC power output from the inverter and outputs the voltage to battery 70. Thereby, battery 70 is charged using the electric power generated by first MG 20 and / or second MG 30. The converter may be omitted.

  The battery 70 is, for example, a secondary battery that includes nickel metal hydride, lithium ions, or the like. The voltage of the battery 70 is about 200V, for example. Battery 70 may be charged using electric power supplied from an external power source (not shown) in addition to being charged using electric power generated by first MG 20 and / or second MG 30 as described above. The battery 70 is not limited to a secondary battery, and may be a large-capacity capacitor, for example.

  The ECU 200 controls the entire hybrid system, that is, the charging / discharging state of the battery 70 and the operating states of the engine 10, the first MG 20 and the second MG 30 so that the vehicle 1 can operate most efficiently by controlling the engine 10, the PCU 60, and the like. .

  In the vehicle 1 having the above-described configuration, the ECU 200 calculates the fluctuation amount of the engine rotational speed Ne (hereinafter simply referred to as “rotational fluctuation amount ΔNe”) at a predetermined period using the detection result of the crank angle sensor 11. It is determined whether or not misfire has occurred in the engine 10 according to whether or not the calculated rotation fluctuation amount ΔNe exceeds the misfire determination value.

  However, when the vehicle 1 travels on a road surface (hereinafter simply referred to as “bad road”) where convex or concave resistance continues, such as a road surface on which a plurality of speed breakers are installed, a Belgian road surface, or the like, A disturbance from the tire is input to the engine 10 every time it comes into contact with the resistance. Due to this influence, the rotational fluctuation amount ΔNe increases momentarily, and there is a possibility that it is erroneously determined that misfire has occurred.

  Therefore, in the present embodiment, when the rotational fluctuation amount ΔNe exceeds the misfire determination value, the ECU 200 does not immediately determine that misfiring has occurred, but the rotational fluctuation amount ΔNe uses the misfire determination value. It is determined whether or not the vehicle is traveling on a rough road by using the rotation fluctuation amount ΔNe calculated during the predetermined period immediately before exceeding. The ECU 200 determines that misfire has occurred when the rotational fluctuation amount ΔNe exceeds the misfire determination value and the vehicle is not traveling on a rough road.

  Hereinafter, the engine 10 is an in-line four-cylinder engine, and ignition is repeated in the order of the first cylinder (# 1), the second cylinder (# 2), the third cylinder (# 3), and the fourth cylinder (# 4). An example will be described.

  FIG. 3 is a functional block diagram of ECU 200. Each functional block shown in FIG. 3 may be realized by hardware or software.

  ECU 200 includes a fluctuation amount calculation unit 210, a temporary misfire determination unit 220, a first misfire determination unit 230, and a second misfire determination unit 240.

  The fluctuation amount calculation unit 210 calculates a rotation fluctuation amount ΔNe (more specifically, “rotation time fluctuation amount ΔT30” described later) using the detection result of the crank angle sensor 11. The fluctuation amount calculation unit 210 measures, for example, the time required for the crankshaft 116 to rotate by a predetermined angle using the detection result of the crank angle sensor 11. In the present embodiment, the predetermined angle is 30 ° CA, and the time required for the crankshaft 116 to rotate 30 ° CA is described as “rotation time T30”.

  FIG. 4 is a diagram illustrating an example of the calculation timing (calculation cycle) of the rotation time T30 and the rotation time fluctuation amount ΔT30. Note that the calculation timing shown in FIG. 4 is merely an example, and the present invention is not limited to this.

  As shown in FIG. 4, the fluctuation amount calculation unit 210 ignites each cylinder for a rotation time T30 required for the crankshaft 116 to rotate by 30 ° CA starting from the TDC (Top Dead Center) of each cylinder. Measure (calculate) every time.

  Further, each time the rotation time T30 is measured, the fluctuation amount calculation unit 210 calculates a value obtained by subtracting the rotation time T30 one ignition before (previous cycle) from the latest (current cycle) rotation time T30. Calculated as an amount ΔT30.

  In the following description, the latest (current cycle) rotation time T30 is “T30 (0)”, and the rotation time T30 before n ignition (n cycles before, n = 1, 2, 3,...) Is “T30 (n)”. Is also described. The latest (current cycle) rotation time variation ΔT30 is also described as “ΔT30 (0)”, and the rotation time variation ΔT30 before n ignition (before n cycles) is also described as “ΔT30 (n)”.

  For example, when the rotation time T30 of the third cylinder is measured in the current cycle, the fluctuation amount calculation unit 210 sets the rotation time T30 of the third cylinder measured in the current cycle to “T30 (0)” and before one ignition. The rotation time T30 of the second cylinder as the cylinder is set to “T30 (1)”, and the rotation time fluctuation amount ΔT30 (0) of the current cycle is set to ΔT30 (0) = T30 (0) −T30 (1).

  The rotation time fluctuation amount ΔT30 calculated in this way is a value that changes according to the fluctuation of the engine rotation speed Ne.

  That is, when the engine rotation speed Ne is lower than before one ignition, the rotation time T30 becomes longer than before one ignition, so the rotation time variation ΔT30 becomes a positive value. Further, as the amount of decrease in the engine rotation speed Ne is larger, the rotation time T30 becomes longer, so the value of the rotation time fluctuation amount ΔT30 becomes larger.

  Conversely, when the engine rotation speed Ne increases from before the first ignition, the rotation time T30 becomes shorter than before the first ignition, so the rotation time variation ΔT30 becomes a negative value. Further, the larger the increase amount of the engine rotation speed Ne, the shorter the rotation time T30, so the value of the rotation time fluctuation amount ΔT30 becomes smaller (the absolute value becomes larger).

  Thus, the rotation time fluctuation amount ΔT30 is a value that changes according to the fluctuation of the engine rotation speed Ne. In the present embodiment, a case where this rotation time variation ΔT30 is used as the rotation variation ΔNe will be described as an example. Note that the value that can be used as the rotation fluctuation amount ΔNe is not limited to the rotation time fluctuation amount ΔT30 as long as it is a value that changes according to the fluctuation of the engine rotation speed Ne.

  The temporary misfire determination unit 220 determines whether or not the latest rotation time fluctuation amount ΔT30 (0) exceeds the misfire determination value α. Here, the misfire determination value α is set to a positive predetermined value. The misfire determination value α may be a fixed value or a fluctuation value that varies depending on the engine rotational speed Ne or the like.

  The temporary misfire determination unit 220 determines “normal (no misfire has occurred)” when the latest rotation time variation ΔT30 (0) does not exceed the misfire determination value α. On the other hand, the temporary misfire determination unit 220, when the latest rotation time fluctuation amount ΔT30 (0) exceeds the misfire determination value α (that is, when the engine speed Ne decreases from the previous cycle to the current cycle by a predetermined speed or more), Judged as “temporary misfire”.

  The first misfire determination unit 230 determines whether the misfire provisional abnormality is continuously determined in the same cylinder when the provisional misfire determination unit 220 determines that the misfire provisional abnormality is present. Specifically, the first misfire determination unit 230 determines whether or not there is a history of a temporary misfire abnormality determined 4 cycles before the current cycle (before 4 ignition) (that is, the rotational time fluctuation amount before 4 ignition). It is determined whether or not ΔT30 (4) has exceeded the misfire determination value α. 4 When the rotational time fluctuation amount ΔT30 (4) before ignition exceeds the misfire determination value α, the misfire is continuously generated in the cylinder determined to be a misfire temporary abnormality in the current cycle. Is determined. Otherwise, it is determined that there is no one-cylinder continuous misfire abnormality.

  When it is determined by the first misfire determination unit 230 that there is no one-cylinder continuous misfire abnormality, the second misfire determination unit 240 uses the rotation time variation ΔT30 during a predetermined period immediately before the current cycle to make the vehicle 1 take a rough road. It is determined whether or not the vehicle is running.

  FIG. 5 is a diagram schematically showing a change pattern of the engine rotation speed Ne, the rotation time T30, and the rotation time fluctuation amount ΔT30 during traveling on a rough road.

  When driving on rough roads, tires come into contact with road resistance regularly. The engine rotation speed Ne temporarily decreases immediately after the tire comes into contact with the resistance, then gradually returns (increases) to a normal value, and then temporarily decreases again when the tire comes into contact with the next resistance. While traveling on a rough road, such a change in the engine rotational speed Ne is repeated.

  When the tire comes into contact with the resistance, the engine rotation speed Ne temporarily decreases (decelerates) and the rotation time T30 increases, so the rotation time fluctuation amount ΔT30 becomes a positive value. Therefore, during traveling on a rough road, although the misfire does not occur, the rotation time fluctuation amount ΔT30 may exceed the misfire determination value α periodically (that is, every time the tire contacts the resistance).

  On the other hand, when the engine speed Ne, which has been temporarily reduced, returns to a normal value, the engine speed Ne is increased and the rotation time T30 is reduced. Therefore, the rotation time fluctuation amount ΔT30 becomes a negative value. Accordingly, during traveling on a rough road, it is assumed that the total or average of the rotation time fluctuation amounts ΔT30 of several cycles immediately before the rotation time fluctuation amount ΔT30 exceeds the misfire determination value α becomes a negative value.

  In consideration of such a change pattern of the rotation time fluctuation amount ΔT30 during traveling on a rough road, the second misfire determination unit 240 calculates the total value of the rotation time fluctuation amounts ΔT30 of the three cycles immediately before the current cycle (= ΔT30 (1)). It is determined whether or not + ΔT30 (2) + ΔT30 (3)) is smaller than a predetermined rough road determination value β. Here, the rough road determination value β is set to a predetermined value equal to or less than zero. An “average value” may be used instead of the “total value” of the rotation time fluctuation amount ΔT30.

  And even if it is a case where it is determined that the temporary misfire is abnormal in the current cycle, the second misfire determination unit 240 has a total value of the rotational time fluctuation amount ΔT30 of the three cycles immediately before the current cycle smaller than the rough road determination value β. In this case, it is determined that the vehicle 1 is traveling on a rough road, and it is not determined that a misfire has occurred. In other words, the second misfire determination unit 240 has accelerated the engine rotational speed Ne by a predetermined speed or more during a predetermined period immediately before the current cycle even when the engine rotational speed Ne has decreased by a predetermined speed or more in the current cycle. In this case, it is determined that the vehicle 1 is traveling on a rough road, and it is not determined that a misfire has occurred. As a result, it is possible to suppress erroneous determination that rotation fluctuation due to running on a rough road is misfired.

  For example, if it is determined that the rotation time variation ΔT30 of the fourth cylinder exceeds the misfire determination value α in the current cycle, the rotation time variation ΔT30 (1) of the third cylinder before one ignition and the second before the second ignition. When the total value of the cylinder rotation time fluctuation amount ΔT30 (2) and the rotation time fluctuation amount ΔT30 (3) of the first cylinder 3 before ignition is smaller than the rough road determination value β, the vehicle 1 is in a rough road. It is determined that the vehicle is traveling, and it is not determined that a misfire has occurred.

  On the other hand, the second misfire determination unit 240 is a value when the temporary misfire abnormality is determined in the current cycle and the total value of the rotation time fluctuation amounts ΔT30 of the three cycles immediately before the current cycle is larger than the rough road determination value β. In some cases, it is determined as “random misfire abnormality” in which misfire has occurred in the cylinder that is determined to be provisional misfire abnormality in the current cycle. In other words, the second misfire determination unit 240 is a case where the engine rotational speed Ne has decreased by a predetermined speed or more in the current cycle and the engine rotational speed Ne has not accelerated by a predetermined speed or more during the predetermined period immediately before the current cycle. Then, it is determined that a misfire has occurred in the cylinder determined to be a temporary misfire abnormality in the current cycle.

  FIG. 6 is a flowchart showing a processing procedure of the ECU 200 for realizing the above-described functions. This flowchart is repeatedly executed every time the rotation time fluctuation amount ΔT30 is calculated.

  In step (hereinafter, step is abbreviated as “S”) 10, ECU 200 determines whether or not rotation time variation amount ΔT30 (0) of the current cycle exceeds misfire determination value α (α> 0).

  If rotation time variation ΔT30 (0) of the current cycle does not exceed misfire determination value α (NO in S10), ECU 200 moves the process to S11, and the combustion state of engine 10 is normal (misfire has occurred). Not).

  If rotation time variation ΔT30 (0) of the current cycle exceeds misfire determination value α (YES in S10), ECU 200 determines that the temporary misfire is abnormal, moves the process to S12, and performs rotation before four ignitions. It is determined whether the time fluctuation amount ΔT30 (4) has exceeded the misfire determination value α.

  If rotational time fluctuation amount ΔT30 (4) before ignition 4 exceeds misfire determination value α (YES in S12), ECU 200 moves the process to S13, and the cylinders that are determined to be misfire temporary abnormality in the current cycle are detected. It is determined that the “one-cylinder continuous misfire abnormality” is occurring.

  If rotation time fluctuation amount ΔT30 (4) before 4 ignition does not exceed misfire determination value α (NO in S12), ECU 200 moves the process to S14, and the rotation time fluctuation amount for the three cycles immediately before the current cycle. It is determined whether or not the total value of ΔT30 (= ΔT30 (1) + ΔT30 (2) + ΔT30 (3)) is smaller than the rough road determination value β (β ≦ 0).

  If the total value of the rotation time fluctuation amount ΔT30 of the three cycles immediately before the current cycle is not smaller than the rough road determination value β (NO in S14), the ECU 200 moves the process to S15 and determines that a temporary misfire is abnormal in the current cycle. It is determined that “random misfire abnormality” in which misfire has occurred in the selected cylinder.

  On the other hand, when the total value of the rotation time fluctuation amount ΔT30 of the three cycles immediately before the current cycle is smaller than rough road determination value β (YES in S14), ECU 200 moves the process to S16, and is traveling on a rough road. judge.

  As described above, in the present embodiment, the rough road running and the misfire occurrence are detected using the total value of the rotation time fluctuation amount ΔT30 (0) of the current cycle and the rotation time fluctuation amount ΔT30 of several cycles immediately before the current cycle. Appropriately discriminates and does not determine that a misfire has occurred when traveling on a rough road. Therefore, misfire determination accuracy can be improved.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1 vehicle, 10 engine, 11 crank angle sensor, 16 drive shaft, 20 1st MG, 30 2nd MG, 40 power split device, 58 speed reducer, 70 battery, 80 drive wheel, 102 air cleaner, 104 throttle valve, 106 cylinder, 108 Injector, 110 Spark plug, 112 Three-way catalyst, 114 Piston, 116 Crankshaft, 118 Intake valve, 120 Exhaust valve, 122 Intake side cam, 124 Exhaust side cam, 126 Mechanism, 200 ECU, 204 Cam angle sensor, 206 Water temperature sensor , 208 Air flow meter, 210 Fluctuation amount calculation unit, 220 Temporary misfire determination unit, 230 First misfire determination unit, 240 Second misfire determination unit.

Claims (3)

An engine having a plurality of cylinders;
A controller for determining whether or not misfire has occurred in the engine,
The control device calculates a fluctuation amount of a time required for the rotation shaft of the engine to rotate by a predetermined angle as a rotation fluctuation amount of the engine, and the rotation fluctuation amount exceeds a positive first predetermined value and If the rotational fluctuation amount during a predetermined period immediately before the rotational fluctuation amount exceeds the first predetermined value is greater than a second predetermined value equal to or less than zero, it is determined that the misfire has occurred ;
Even if the rotational fluctuation amount exceeds the first predetermined value, if the rotational fluctuation amount during the immediately preceding predetermined period is smaller than the second predetermined value, the vehicle is traveling on a rough road. A vehicle that determines that the misfire has occurred and determines that the misfire has occurred . The control device calculates the rotation fluctuation amount at a predetermined calculation cycle,
The rotation fluctuation amount during the immediately preceding predetermined period is a sum or average of a plurality of rotation fluctuation amounts calculated in a plurality of calculation cycles immediately before the rotation fluctuation amount exceeds the first predetermined value. The vehicle according to 1 . The plurality of cylinders are ignited in a predetermined order,
The control device calculates the rotation fluctuation amount at a calculation cycle according to the ignition timing of the plurality of cylinders, and when the rotation fluctuation amount continuously exceeds the first predetermined value in the same cylinder, the immediately preceding Regardless of whether or not the rotational fluctuation amount during a predetermined period is greater than the second predetermined value, the misfire occurs in a cylinder in which the rotational fluctuation amount exceeds the first predetermined value continuously. determining vehicle according to claim 1 or 2.

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