JP2013154810A - Misfire determination device of hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent erroneous determination as to misfire of an internal combustion engine even when a torque ripple phenomenon occurs in an electric motor of a hybrid vehicle.SOLUTION: A misfire determination device is applied to a hybrid vehicle including: an internal combustion engine having an output shaft connected to a drive shaft of the hybrid vehicle so as to be able to transmit torque; and an electric motor having a rotor connected to the drive shaft so as to be able to transmit torque and a stator. The misfire determination device performs misfire determination of the internal combustion engine based on fluctuation in the rotational speed of the output shaft of the internal combustion engine. The misfire determination device inhibits, when the rotor is substantially still with respect to the stator while torque is output from the electric motor to the drive shaft and the internal combustion engine is driven, misfire determination when a condition of a torque ripple phenomenon where the torque outputted from the electric motor continuously increases/decreases is established.

Description

  The present invention relates to a misfire determination device for a hybrid vehicle that determines whether or not misfire has occurred in an internal combustion engine provided in the hybrid vehicle.

  As is well known, a hybrid vehicle includes an internal combustion engine and an electric motor as a drive source that generates a drive force for running the vehicle. The hybrid vehicle travels by transmitting torque generated by one or both of the internal combustion engine and the electric motor to a drive shaft connected to the drive wheels.

  In an internal combustion engine provided in a hybrid vehicle, misfire may occur as in an internal combustion engine provided in a general vehicle that is not a hybrid vehicle (hereinafter also referred to as “general vehicle” for convenience). Therefore, a conventional misfire determination device for a hybrid vehicle (hereinafter also referred to as a “conventional device”) pays attention to the fact that misfire affects the engine rotation speed, as well as the rate of change in engine rotation speed and misfire determination. Therefore, it is determined whether or not the internal combustion engine has misfired by comparing with a threshold value. Furthermore, the conventional device increases the accuracy of misfire determination by changing the threshold value depending on whether or not the pressing torque from the electric motor to the gear mechanism is output (for example, Patent Document 1). See). Thus, conventionally, it is desired to perform misfire determination of an internal combustion engine provided in a hybrid vehicle as accurately as possible.

JP 2010-126064 A

  In a hybrid vehicle (hereinafter, also simply referred to as “vehicle” for convenience), unlike an ordinary vehicle, the internal combustion engine and the drive shaft of the vehicle are not only coupled so as to be able to transmit torque, The motor is also connected to be able to transmit torque. Therefore, it is considered that not only the misfire of the internal combustion engine but also the operating state of the electric motor can affect the engine rotational speed of the internal combustion engine.

  For example, when the vehicle is stationary on an uphill road, torque is output from at least one of the electric motor and the internal combustion engine so that a force having the same magnitude as the force due to gravity that tries to reverse the vehicle acts on the drive shaft. Will be. In other words, at this time, the torque that the drive shaft tries to rotate in the direction in which the vehicle goes down the slope (hereinafter also referred to as “reverse direction” for convenience), and at least one of the electric motor and the internal combustion engine The torque to rotate in the direction in which the drive shaft climbs the uphill road (hereinafter also referred to as “forward direction” for convenience) is balanced. Here, since the drive shaft and the rotor (rotor) of the electric motor are connected so as not to rotate relative to each other, the rotor (rotor) of the electric motor also does not rotate with respect to the stator (stator) when the drive shaft does not rotate. become. In other words, a torque that can fix the position of the rotor so that the rotor does not rotate with respect to the stator is output from the electric motor.

  In general, an electric motor outputs torque by sequentially passing current through a circuit (winding) corresponding to each magnetic field so that a magnetic field in a direction in which the rotor rotates with respect to the stator can be sequentially generated ( It is configured to generate a force in the direction of rotating the rotor. Therefore, when the rotor does not rotate while torque is output from the electric motor as described above, current continues to flow through a specific circuit. However, it is not desirable that a current continues to flow in a specific circuit for a long time from the viewpoint of protecting the circuit.

  Therefore, when there is a possibility that a current continues to flow through a specific circuit for a long time, the current may be intermittently and repeatedly supplied to the circuit in order to protect the circuit. In this case, the torque output from the electric motor repeatedly increases and decreases (so-called hunting occurs) intermittently as the current is energized and interrupted. In this case, the length of time that the current is cut off is such that the drive shaft of the vehicle does not substantially rotate in the reverse direction (that is, the current is cut off and the rotor of the motor is slightly rotated from the initial position). Is energized again and the rotor immediately returns to the initial position, so that the rotor can be regarded as substantially not rotating). In the present invention, as described above, the phenomenon in which the output torque of the motor increases or decreases is referred to as “torque ripple phenomenon”.

  Incidentally, as described above, when the vehicle is stationary on the uphill road by the output torque of the electric motor, the internal combustion engine may be driven for the purpose of warming up the internal combustion engine. In this case, when the rotational position of the rotor fluctuates due to the torque ripple phenomenon (when reciprocating around the initial position, hereinafter also referred to as “vibration”), the engine rotational speed of the internal combustion engine is also It is thought that it fluctuates. For example, when the internal combustion engine emits only a torque that can maintain the self-sustained operation (that is, the engine generates a torque that can maintain the engine speed against the frictional resistance between the constituent members, etc. Even when the torque is not substantially output to the drive shaft of the motor), the load of the internal combustion engine increases by an amount corresponding to the torque at which the motor is no longer generated at the moment when the current of the motor is cut off. It is considered that the engine speed of the internal combustion engine may fluctuate (vibrate).

  In the conventional apparatus, it is considered that when the engine rotational speed of the internal combustion engine varies due to the torque ripple phenomenon of the electric motor as described above, the variation may be recognized as being caused by misfire of the internal combustion engine. That is, due to the torque ripple phenomenon of the electric motor, misfire determination of the internal combustion engine may be made erroneously (incorrect determination is made). Such a misjudgment is undesirable from the viewpoint of making the misfire judgment of the internal combustion engine as accurately as possible.

  In view of the above problems, an object of the present invention is to make a hybrid vehicle misfire determination that can prevent erroneous determination in misfire determination of an internal combustion engine even when a torque ripple phenomenon occurs in an electric motor of the hybrid vehicle. To provide an apparatus.

A misfire determination device for a hybrid vehicle according to the present invention for solving the above-described problem is as follows.
An internal combustion engine having an output shaft coupled to a drive shaft of the hybrid vehicle so as to transmit torque;
An electric motor having a rotor connected to the drive shaft so as to be able to transmit torque, and a stator;
And applied to hybrid vehicles with
The misfire determination of the internal combustion engine is performed based on fluctuations in the rotational speed of the output shaft of the internal combustion engine.

Furthermore, the misfire determination device of the present invention having the above-described configuration is
While the torque is output from the electric motor to the drive shaft, the torque output from the electric motor continues when the rotor is substantially stationary with respect to the stator and the internal combustion engine is driven. When the condition for causing the “torque ripple phenomenon” to repeatedly increase and decrease is satisfied, the misfire determination is “prohibited”.

  According to the above configuration, if a torque ripple phenomenon occurs when torque is output from the electric motor but the rotor (rotor) is not substantially rotating, the misfire determination of the internal combustion engine is prohibited. Therefore, even if the engine speed of the internal combustion engine fluctuates due to the torque ripple phenomenon of the electric motor, it is not determined that the fluctuation is due to misfire. Thereby, even when a torque ripple phenomenon occurs in the electric motor, it is possible to prevent an erroneous determination in the misfire determination of the internal combustion engine.

  By the way, the “forbidden misfire determination” may be realized by an appropriate method from the viewpoint of preventing erroneous determination in misfire determination, and the specific prohibition method is not particularly limited. For example, as a method of prohibiting misfire determination, the process of performing misfire determination itself is canceled, and the process of performing misfire determination itself ignores the determination result obtained while being executed (not adopted in the subsequent processes). Can be adopted.

  The “internal combustion engine” is not particularly limited as long as it can be applied to a hybrid vehicle. For example, a spark ignition internal combustion engine (so-called gasoline engine) and a compression self-ignition internal combustion engine (so-called diesel engine) can be adopted as the internal combustion engine. The “motor” is not particularly limited as long as it can be applied to a hybrid vehicle.

  The term “substantially stationary” means that the rotor (rotor) is stationary with respect to the stator (stator) and that it is stationary in view of the presence or absence of the torque ripple phenomenon. The rotor is rotating relative to the stator at an appreciable speed (for example, the vehicle speed of the hybrid vehicle related to the rotation of the rotor is less than the resolution of the means for detecting the vehicle speed) Etc.).

  In the misfire determination apparatus of the present invention, a specific method for determining whether or not the torque ripple phenomenon has occurred is not particularly limited.

For example, as an example of a specific configuration, the misfire determination device of the present invention is
The vehicle speed of the hybrid vehicle is below a threshold vehicle speed,
The rate of change of the operating parameter used to determine the torque output from the electric motor is equal to or less than the threshold rate of change, and
When the degree of variation in torque output from the electric motor is equal to or greater than a threshold degree,
It may be configured such that “the condition for causing the torque ripple phenomenon” is satisfied.

  For example, the situation where the vehicle speed of the hybrid vehicle is equal to or lower than the threshold vehicle speed and the change rate of the driving parameter used to determine the torque output from the electric motor is equal to or lower than the threshold change rate is, for example, that the vehicle is on an uphill road May occur when the vehicle is stationary and when the vehicle is climbing up the slope at a low speed.

  By the way, the “operating parameter” is not particularly limited as long as it is an operating parameter employed for determining the torque to be output from the electric motor. For example, the amount of accelerator operation of the vehicle can be adopted as the driving parameter.

  The “degree of fluctuation in torque output from the electric motor” is not particularly limited as long as the fluctuation of the torque can be objectively determined. For example, as the degree of fluctuation of the torque output from the electric motor, the total amount of the absolute value of the change amount of the torque during a predetermined time length and the standard deviation of the torque during the predetermined time length are adopted. Can be done.

  As described above, the misfire determination device for a hybrid vehicle according to the present invention prevents erroneous determination of misfire determination of the internal combustion engine even when a torque ripple phenomenon occurs in the electric motor of the hybrid vehicle. There is an effect that can be done.

  As can be understood from the above description, the torque ripple phenomenon in the present invention is a torque ripple in the sense generally used for the output torque of a motor (the output torque pulsates due to the distribution of magnetic flux density). It is different from (phenomenon).

1 is a schematic diagram of a hybrid vehicle to which a misfire determination device according to a first embodiment of the present invention is applied. It is a schematic flowchart which shows the view of control in the misfire determination apparatus which concerns on 1st Embodiment of this invention. It is a flowchart which shows the basic action | operation of the hybrid vehicle with which the misfire determination apparatus which concerns on 2nd Embodiment of this invention is applied. It is the graph which showed the relationship between the accelerator operation amount and vehicle speed, and a user request | requirement torque relevant to the basic action | operation shown in FIG. FIG. 4 is a graph showing the relationship between the engine rotation speed and the engine output torque and the optimum engine operation line related to the basic operation shown in FIG. 3. FIG. 4 is a collinear diagram of the planetary gear device during traveling of the hybrid vehicle related to the basic operation shown in FIG. 3. It is the flowchart which showed the routine which engine ECU performs in the misfire determination apparatus which concerns on 2nd Embodiment of this invention.

  Hereinafter, each embodiment (1st Embodiment and 2nd Embodiment) of the misfire determination apparatus by this invention is described, referring drawings.

(First embodiment)
<Outline of device>
FIG. 1 shows a schematic configuration of a system in which a misfire determination device (hereinafter also referred to as “first device”) according to a first embodiment of the present invention is applied to a hybrid vehicle 10. Hereinafter, for convenience, the hybrid vehicle 10 is also simply referred to as “vehicle 10”.

  As shown in FIG. 1, the vehicle 10 includes a generator motor MG1, a generator motor MG2, an internal combustion engine 20 (hereinafter also simply referred to as “engine 20”), a power distribution mechanism 30, output shafts 41 and 42, a drive. A force transmission mechanism 50, a first inverter 61, a second inverter 62, a battery 63, a power management ECU 70, a battery ECU 71, a motor ECU 72, an engine ECU 73, and a plurality of sensors 81 to 85 and 91 to 98 are provided. The ECU is an abbreviation for an electric control unit and is an electronic control circuit having a microcomputer including a CPU, a ROM, a RAM, an interface, and the like as main components.

  The generator motor (motor generator) MG1 is a synchronous generator motor that can function as both a generator and a motor. The generator motor MG1 is also referred to as a first generator motor MG1 for convenience. The first generator motor MG1 mainly functions as a generator in this example. The first generator motor MG1 has an output shaft (hereinafter also referred to as “first shaft”) 41.

  The generator motor (motor generator) MG2 is a synchronous generator motor that can function as both the generator and the motor, like the first generator motor MG1. The generator motor MG2 is also referred to as a second generator motor MG2 for convenience. The second generator motor MG2 mainly exhibits a function as a motor in this example. The second generator motor MG <b> 2 has an output shaft (hereinafter also referred to as “second shaft”) 42.

  The second generator motor MG2 includes a rotor (rotor) MG2r connected to the output shaft 42 and a stator (stator) MG2s. Then, the second generator motor MG2 sequentially applies currents to the circuits (windings) corresponding to the respective magnetic fields so that the rotor MG2r can sequentially generate magnetic fields in the direction in which the rotor MG2r rotates with respect to the stator MG2s. The torque is output to the output shaft 42 (a force in the direction of rotating the rotor MG2r is generated). The first generator motor MG1 is configured similarly to the second generator motor MG2 except that torque is output to the output shaft 41.

  The engine 20 is a four-cycle / spark ignition / multi-cylinder internal combustion engine. The engine 20 includes an intake passage 21 including an intake pipe and an intake manifold, a throttle valve 22, a throttle valve actuator 22a, a plurality of fuel injection valves 23, a plurality of ignition devices 24 including an ignition plug, and a crank that is an output shaft of the engine 20 A shaft 25, an exhaust manifold 26, an exhaust pipe 27, and three-way catalysts 28a and 28b are provided. The engine 20 may have a variable intake / exhaust valve control device (VVT) (not shown).

  The throttle valve 22 is rotatably supported by the intake passage portion 21. The throttle valve actuator 22a rotates the throttle valve 22 in response to an instruction signal from the engine ECU 73, and can change the passage sectional area of the intake passage portion 21.

  Each of the plurality of fuel injection valves 23 (only one fuel injection valve 23 is shown in FIG. 1) is arranged such that its injection hole is exposed to an intake port communicating with the combustion chamber. Each of the fuel injection valves 23 is configured to inject a predetermined amount of fuel into the intake port in response to an instruction signal from the engine ECU 73.

  Each of the ignition devices 24 generates an ignition spark at a specific ignition timing (ignition timing) in the combustion chamber of each cylinder in response to an instruction signal from the engine ECU 73.

  The crankshaft 25 is connected to the power distribution mechanism 30 so that torque generated by the engine 20 can be input to the power distribution mechanism 30 (details will be described later).

  Three-way catalysts 28 a and 28 b are provided in the exhaust manifold 26 of the exhaust manifold 26 and the exhaust pipe 27 on the downstream side of the exhaust manifold 26. The three-way catalysts 28a, 28b are exhaust purification catalysts, and purify unburned substances (HC, CO, etc.) and nitrogen oxides (NOx) discharged from the engine 20.

  The power distribution mechanism 30 includes a known planetary gear device 31. The planetary gear device 31 includes a sun gear 32, a plurality of planetary gears 33, and a ring gear 34.

  The sun gear 32 is connected to the first shaft 41 of the first generator motor MG1. Therefore, the first generator motor MG <b> 1 can output torque to the sun gear 32. Conversely, the first generator motor MG1 can generate power by being rotationally driven by torque input from the sun gear 32 to the first generator motor MG1 (first shaft 41).

  Each of the plurality of planetary gears 33 meshes with the sun gear 32 and meshes with the ring gear 34. The planetary gear 33 has a rotation shaft (spinning shaft) provided on the planetary carrier 35. The planetary carrier 35 is held so as to be rotatable coaxially with the sun gear 32. Similarly, the ring gear 34 is held so as to be rotatable coaxially with the sun gear 32. Therefore, the planetary gear 33 can revolve while rotating on the outer periphery of the sun gear 32. The planetary carrier 35 is connected to the crankshaft 25 of the engine 20. Therefore, the planetary gear 33 can be rotationally driven by the torque input from the crankshaft 25 to the planetary carrier 35.

  Further, as described above, the planetary gear 33 meshes with the sun gear 32 and the ring gear 34. Therefore, when torque is input from the planetary gear 33 to the sun gear 32, the sun gear 32 is rotationally driven by the torque. When torque is input from the planetary gear 33 to the ring gear 34, the ring gear 34 is rotationally driven by the torque. Conversely, when torque is input from the sun gear 32 to the planetary gear 33, the planetary gear 33 is rotationally driven by the torque. When torque is input from the ring gear 34 to the planetary gear 33, the planetary gear 33 is rotationally driven by the torque.

  The ring gear 34 is connected to the second shaft 42 of the second generator motor MG2 via the ring gear carrier 36. Therefore, the second generator motor MG <b> 2 can output torque to the ring gear 34. On the contrary, the second generator motor MG2 can generate electric power by being rotationally driven by the torque input from the ring gear 34 to the second generator motor MG2 (second shaft 42).

  Further, the ring gear 34 is connected to an output gear 37 via a ring gear carrier 36. Therefore, the output gear 37 can be rotationally driven by the torque input from the ring gear 34 to the output gear 37. Conversely, the ring gear 34 can be driven to rotate by torque input from the output gear 37 to the ring gear 34.

  The driving force transmission mechanism 50 includes a gear train 51, a differential gear 52, and a drive shaft (drive shaft) 53.

  The gear train 51 connects the output gear 37 and the differential gear 52 by a gear mechanism so that power can be transmitted. The differential gear 52 is attached to the drive shaft 53. Drive wheels 54 are attached to both ends of the drive shaft 53. Therefore, torque from the output gear 37 is transmitted to the drive wheel 54 via the gear train 51, the differential gear 52, and the drive shaft 53. The hybrid vehicle 10 can travel by the torque transmitted to the drive wheels 54.

  The first inverter 61 is electrically connected to the first generator motor MG <b> 1 and the battery 63. Therefore, when the first generator motor MG1 is generating power, the electric power generated by the first generator motor MG1 is supplied to the battery 63 via the first inverter 61. Conversely, the first generator motor MG1 is driven to rotate by the electric power supplied from the battery 63 via the first inverter 61.

  The second inverter 62 is electrically connected to the second generator motor MG <b> 2 and the battery 63. Therefore, the second generator motor MG2 is driven to rotate by the electric power supplied from the battery 63 via the second inverter 62. Conversely, when the second generator motor MG <b> 2 is generating power, the electric power generated by the second generator motor MG <b> 2 is supplied to the battery 63 via the second inverter 62.

  The electric power generated by the first generator motor MG1 can be directly supplied to the second generator motor MG2, and the electric power generated by the second generator motor MG2 can be directly supplied to the first generator motor MG1.

  The battery 63 is a lithium ion battery in this example. However, the battery 63 may be a power storage device that can be discharged and charged, and may be a nickel metal hydride battery or another secondary battery.

  The power management ECU 70 (hereinafter also referred to as “PMECU 70”) is connected to the battery ECU 71, the motor ECU 72, and the engine ECU 73 so as to exchange information through communication.

  The PM ECU 70 is connected to a power switch 81, a shift position sensor 82, an accelerator operation amount sensor 83, a brake switch 84, a vehicle speed sensor 85, and the like, and an output signal generated by these sensors is input.

  The power switch 81 is a system activation switch for the hybrid vehicle 10. The PM ECU 70 is configured to start the system (become Ready-On state) when the power switch 81 is operated when a vehicle key (not shown) is inserted into the key slot and the brake pedal is depressed. ing.

  The shift position sensor 82 generates a signal indicating a shift position selected by a shift lever (not shown) provided near the driver's seat of the hybrid vehicle 10 so as to be operable by an operator. The shift positions include P (parking position), R (reverse position), N (neutral position), and D (travel position).

  The accelerator operation amount sensor 83 generates an output signal indicating an operation amount (accelerator operation amount AP) of an accelerator pedal (not shown) provided so as to be operable by an operator.

  The brake switch 84 generates an output signal indicating that the brake pedal is in an operated state when a brake pedal (not shown) that can be operated by an operator is operated.

  The vehicle speed sensor 85 generates an output signal representing the vehicle speed SPD of the hybrid vehicle 10.

  The PM ECU 70 is input with a charge rate SOC (State Of Charge) of the battery 63 calculated by the battery ECU 71. The charging rate SOC is calculated by a known method based on the integrated value of the current flowing into and out of the battery 63.

  The PM ECU 70, via the motor ECU 72, signals representing the rotational speed of the first generator motor MG1 (hereinafter also referred to as “MG1 rotational speed Nm1”) and the rotational speed of the second generator motor MG2 (hereinafter referred to as “MG2 rotation”). It is also called “speed Nm2”).

  The MG1 rotation speed Nm1 is calculated by the motor ECU 72 based on “the output value of the resolver 97 provided in the first generator motor MG1 and outputting an output value corresponding to the rotation angle of the rotor MG1r of the first generator motor MG1”. Has been. Similarly, the MG2 rotational speed Nm2 is determined by the motor ECU 72 based on “the output value of the resolver 98 that is provided in the second generator motor MG2 and outputs an output value corresponding to the rotational angle of the rotor MG2r of the second generator motor MG2”. It has been calculated.

  The PM ECU 70 is input with various output signals representing the engine state via the engine ECU 73. The output signal representing the engine state includes the engine speed Ne, the throttle valve opening, the engine coolant temperature, and the like.

  The motor ECU 72 is connected to the first inverter 61 and the second inverter 62. The motor ECU 72 sends instruction signals to the first inverter 61 and the second inverter 62 based on commands from the PM ECU 70 (“MG1 command torque Tm1 * and MG2 command torque Tm2 *, which will be described later). Thus, the motor ECU 72 controls the first generator motor MG1 using the first inverter 61, and controls the second generator motor MG2 using the second inverter 62.

  The engine ECU 73 is connected to the throttle valve actuator 22a, the fuel injection valve 23, the ignition device 24, and the like, and sends instruction signals to these. Further, the engine ECU 73 is connected to an air flow meter 91, a throttle valve opening sensor 92, a coolant temperature sensor 93, an engine speed sensor 94, a knocking sensor 95, an air-fuel ratio sensor 96, and the like, and outputs output signals generated by these. To get.

  The air flow meter 91 measures the amount of air per unit time taken into the engine 20 and outputs a signal representing the amount of air (intake air amount).

  The throttle valve opening sensor 92 detects the opening of the throttle valve 22 (throttle valve opening) and outputs a signal representing the detected throttle valve opening.

  The coolant temperature sensor 93 detects the coolant temperature of the engine 20 and outputs a signal representing the detected coolant temperature.

  The engine speed sensor 94 outputs a signal having a narrow pulse every time the crankshaft 25 of the engine 20 rotates 10 °, and outputs a signal having a wide pulse every time the crankshaft 25 rotates 360 °. It is designed to output. The engine ECU 73 acquires the rotational speed (engine rotational speed) Ne of the crankshaft 25 per unit time based on these pulse signals. Further, the engine ECU 73 determines the time length required for the crankshaft 25 to rotate by a desired angle (for example, 30 °) that is a natural number multiple of 10 ° based on the pulse signal output from the engine speed sensor 94. You can also get it.

  The knocking sensor 95 is provided on the surface portion of the engine 20. The knocking sensor 95 detects the vibration of the engine 20 and outputs a signal corresponding to the vibration. The engine ECU 73 acquires the knocking intensity based on this signal.

  The air-fuel ratio sensor 96 is an exhaust collecting portion of the exhaust manifold 26 and is provided at a position upstream of the three-way catalyst 28a. The air fuel ratio sensor 96 is a so-called “limit current type wide area air fuel ratio sensor”. The air-fuel ratio sensor 96 detects the air-fuel ratio of the exhaust gas, and outputs an output value corresponding to the detected air-fuel ratio (detected air-fuel ratio) of the exhaust gas. The engine ECU 73 obtains the detected air-fuel ratio by applying this output value to the lookup table.

The engine ECU 73 instructs the throttle valve actuator 22a, the fuel injection valve 23, the ignition device 24 (further, a variable intake valve control device (not shown)) and the like based on signals acquired from these sensors and the command from the PM ECU 70. Is sent to control the engine 20.
The above is the schematic configuration of the system in which the first device is applied to the hybrid vehicle 10.

<Concept of control>
Next, the concept of control in the first device will be described with reference to FIG. FIG. 2 is a “schematic flowchart” showing an outline of the operation of the first device.

  In step 210 of FIG. 2, the first device determines whether or not the engine 20 is being driven. For example, the first device determines whether or not the engine 20 is being driven based on the rotational speed of the crankshaft 25 of the engine 20 or the like. If the engine 20 is currently being driven, the first device makes a “Yes” determination at step 210 and proceeds to step 220.

  In step 220, the first device is configured such that the rotor (rotor MG2r) of the motor is substantially stationary with respect to the stator (stator MG2s) while torque is output from the motor (second generator motor MG2) at the present time. It is determined whether or not. When torque is output from the electric motor and the rotor of the electric motor is substantially stationary with respect to the stator, the first device determines “Yes” in step 220 and proceeds to step 230.

  In step 230, the first device determines whether a torque ripple phenomenon has occurred at the present time. A specific determination method as to whether or not the torque ripple phenomenon has occurred will be described later.

  When the torque ripple phenomenon has occurred at the present time, the first device determines “Yes” in step 230 and proceeds to step 240 to prohibit misfire determination. Specifically, in this case, the misfire determination is not performed.

  On the other hand, if the torque ripple phenomenon does not occur at the present time, the first device determines “No” in step 230 and proceeds to step 250 to execute misfire determination. That is, in this case, it is determined whether or not misfire has occurred at the present time. A specific misfire determination method will be described later.

By the way, when the engine 20 is not currently driven, or when torque is output from the electric motor and the rotor of the electric motor is not substantially stationary with respect to the stator, the first device performs step 210 or In step 220, “No” is determined. Therefore, misfire determination is not performed in these cases.
The above is the description of the first device.

(Second Embodiment)
Next, an embodiment that more specifically describes the misfire determination method in the present invention will be described. Hereinafter, the misfire determination device in this embodiment is also referred to as a “second device”.

<Concept of control>
In the second device, whether or not the torque is output from the second generator motor MG2 is determined by “whether the command torque to the second generator motor MG2 is not zero”, and the rotor of the second generator motor MG2 is determined. Whether or not MG2r is substantially stationary with respect to stator MG2s is determined by “whether or not the vehicle speed is smaller than a predetermined threshold value”.

  Further, in the second device, whether or not the condition for causing the torque ripple phenomenon is satisfied is “whether or not the vehicle speed is equal to or less than a predetermined threshold value, or whether or not the rate of change in the accelerator operation amount is equal to or less than the predetermined threshold value. And whether or not the total amount of the absolute value of the change amount of the output torque of the second generator motor MG2 during the predetermined time length is equal to or larger than a predetermined threshold value.

  And in 2nd apparatus, when said each conditions are satisfy | filled, misfire determination is prohibited (misfire determination is not performed).

<Basic operation>
Hereinafter, before the actual operation of the second device is described, the basic operation of the hybrid vehicle 10 will be described with reference to FIGS. 3 to 6. The processing described below is executed by “CPU of PM ECU 70 and CPU of engine ECU 73”. Hereinafter, in order to simplify the description, the CPU of the PM ECU 70 is also referred to as “PM”, and the CPU of the engine ECU 73 is also referred to as “EG”.

  The hybrid vehicle 10 generates a torque equal to the “user requested torque Tu *, which is a torque determined according to the user's accelerator operation amount AP and required for the drive shaft 53 of the vehicle,” and “the efficiency of the engine 20 is By controlling the output torque Te * of the engine 20 and the output torques Tm1 * and Tm2 * of the motor while making the best (that is, operating the engine 20 at the optimum engine operating point described later) It acts on the drive shaft 53.

  Actually, the hybrid vehicle 10 controls the engine 20, the first generator motor MG1, and the second generator motor MG2 in association with each other. This control is performed, for example, in Japanese Patent Application Laid-Open No. 2009-126450 (US Published Patent Number US2010 / 0241297) and Japanese Patent Application Laid-Open No. 9-308012 (US Patent No. 6, March 10, 1997). 131, 680) and the like. These contents are incorporated herein by reference.

  For example, the vehicle 10 stops the operation of the engine 20 when the engine 20 cannot be operated at an efficiency higher than a predetermined efficiency because the user request torque Tu * is small, and only the output torque of the generator motors MG1, MG2 is output. To satisfy the user requested torque Tu *. On the other hand, the vehicle 10 may be operated when the engine 20 can be operated at an efficiency higher than a predetermined efficiency because the user requested torque Tu * is increased while the operation of the engine 20 is stopped. And the user requested torque Tu * is satisfied by both the output torque of the engine 20 and the generator motors MG1, MG2. It should be noted that such an operation involving “stopping and starting the engine” is intermittently executed and is also referred to as “intermittent operation or intermittent engine operation”.

  More specifically, the above control repeatedly executes the “driving force control routine” shown in the flowchart of FIG. 3 every time a predetermined time elapses when the shift position is at the travel position (D). It is like that. Therefore, at a specific timing, the PM starts processing from step 300 in FIG. 3, and proceeds to step 320 after performing steps 305 to 315 described later in this order.

Step 305:
The PM acquires the ring gear request torque Tr * based on the accelerator operation amount AP and the vehicle speed SPD, and determines the user request output Pr *.

  More specifically describing this step, the torque acting on the drive shaft 53 (drive shaft torque) and the torque acting on the rotating shaft of the ring gear 34 are in a proportional relationship. Therefore, the user request torque Tu * (the torque required for the drive shaft 53 determined according to the user's accelerator operation amount AP) and the ring gear request torque Tr * requested by the user for traveling of the hybrid vehicle 10 Are proportional. Therefore, the PM determines that “the relationship between the accelerator operation amount AP and the vehicle speed SPD and the user request torque Tu *” shown in FIG. 4 is “the accelerator operation amount AP and the vehicle speed SPD, and the ring gear request torque Tr *”. The table having the data converted into “relationship between” and “torque map MapTr * (AP, SPD)” is stored in the ROM. Then, the PM acquires the ring gear required torque Tr * by applying the current “accelerator operation amount AP and vehicle speed SPD” to the torque map MapTr * (AP, SPD).

  On the other hand, the output required for the drive shaft 53 is equal to the product (Tu * · SPD) of the user requested torque Tu * and the actual vehicle speed SPD. This product (Tu * · SPD) is equal to the product (Tr * · Nr) of the ring gear required torque Tr * and the rotational speed Nr of the ring gear 34. Therefore, hereinafter, the product (Tr * · Nr) is referred to as “user request output Pr *”. That is, the user request output Pr * is determined by the user request torque Tu *. Furthermore, in this example, the ring gear 34 is connected to the second shaft 42 of the second generator motor MG2 without passing through a reduction gear. Therefore, the rotational speed Nr of the ring gear 34 is equal to the second MG rotational speed Nm2. Therefore, the user request output Pr * is equal to the product (Tr * · Nm2) of the ring gear request torque Tr * and the second MG rotation speed Nm2.

  If the ring gear 34 is connected to the second shaft 42 via a reduction gear, the rotation speed Nr of the ring gear 34 is a value obtained by dividing the second MG rotation speed Nm2 by the gear ratio Gr of the reduction gear. Equal to (Nm2 / Gr). Therefore, in this case, the user request output Pr * is calculated as a value (Tr * · Nm2 / Gr).

Step 310:
PM acquires battery charge request output Pb * based on the charge rate SOC. The battery charge request output Pb * is a value corresponding to the power to be supplied to the battery 63 in order to charge the battery 63. The battery charge request output Pb * is calculated to be zero when the charging rate SOC is equal to or greater than the predetermined value SOCLOth, and increases as the charging rate SOC decreases when the charging rate SOC is smaller than the predetermined value SOCLOth. Calculated.

Step 315:
The PM acquires a value (Pr * + Pb * + Ploss) obtained by adding the loss Ploss to the sum of the user request output Pr * and the battery charge request output Pb * as the engine request output Pe *. The engine required output Pe * is an output required for the engine 20.

  After performing the processing in steps 305 to 315, the PM proceeds to step 320 and determines whether or not the engine request output Pe * is equal to or greater than the threshold request output Peth. This threshold required output Peth is set to a value such that when the output of the engine 20 is operated less than the threshold required output Peth, the operating efficiency (that is, fuel consumption) of the engine 20 is less than the allowable limit. In other words, the threshold required output Peth is set to such a value that “the efficiency” when the engine 20 outputs the output equal to the threshold required output Peth at the highest efficiency is below the allowable limit.

  Here, when the engine required output Pe * is equal to or greater than the threshold required output Peth, the PM determines “Yes” in step 320 and proceeds to step 325, and the engine 20 is currently stopped (stopped). It is determined whether or not there is.

  If the engine 20 is currently stopped, the PM determines “Yes” in step 325 and proceeds to step 330 to transmit an instruction (start instruction) to start operation of the engine 20 to the EG. Based on this instruction, the EG drives the starter and / or the first generator motor MG1 (not shown) and operates the fuel injection valve 23 and the ignition device 24 to start the engine 20. Thereafter, PM proceeds to step 335. On the other hand, if the engine 20 is currently operating, the PM determines “No” in step 325 and proceeds directly to step 335.

  Thereafter, the PM performs the processing of Step 335 to Step 360 described later in this order.

Step 335:
In order to operate the engine 20 so that the output equal to the engine required output Pe * is output from the engine 20 and the operating efficiency of the engine 20 is the best, PM is the optimum engine corresponding to the engine required output Pe * in this step. Based on the operating point (see FIG. 5), the target engine output torque Te * and the target engine speed Ne * are determined.

  More specifically, in this step, the engine operating point at which the operating efficiency (fuel consumption) of the engine 20 is the best when a certain output is output from the crankshaft 25 is determined as the optimum engine operating point by experiment or the like for each output. It is requested in advance. These optimum engine operating points are plotted on a graph defined by the engine output torque Te and the engine rotational speed Ne, and a line formed by connecting these plots is obtained as the optimum engine operating line. The optimum engine operating line thus obtained is indicated by a solid line Lopt in FIG. In FIG. 5, each of a plurality of lines C0 to C5 indicated by broken lines is a line (equal output line) connecting engine operating points at which the same output can be output from the crankshaft 25.

  The PM searches for an optimal engine operating point at which an output equal to the engine required output Pe * is obtained, and the “engine output torque Te and engine rotational speed Ne” corresponding to the searched optimal engine operating point is set to “target engine output torque”. Te * and target engine speed Ne * ". For example, when the engine required output Pe * is equal to the output corresponding to the line C2 in FIG. 5, the engine output torque Te1 for the intersection P1 between the line C2 and the solid line Lopt is determined as the target engine output torque Te *, and the engine for the intersection P1. The rotational speed Ne1 is determined as the target engine rotational speed Ne *. Note that the output corresponding to the threshold request output Peth corresponds to the output indicated by the line C4 in this example.

Step 340:
PM substitutes “the second MG rotational speed Nm2 equal to the rotational speed Nr” as the rotational speed Nr of the ring gear 34 and substitutes the target engine rotational speed Ne * as the engine rotational speed Ne in the following equation (1). Thus, “MG1 target rotational speed Nm1 * equal to the target rotational speed Ns * of the sun gear 32” is calculated.

  Nm1 = Ns = Nr− (Nr−Ne) · (1 + ρ) / ρ (1)

  In the above equation (1), “ρ” is a value defined by the following equation (2). That is, “ρ” is the ratio of the number of teeth of the sun gear 32 to the number of teeth of the ring gear 34.

  ρ = (number of teeth of sun gear 32 / number of teeth of ring gear 34) (2)

  Here, the basis of the above equation (1) will be described. The relationship between the rotational speeds of the respective gears in the planetary gear unit 31 is represented by a well-known collinear chart shown in FIG. The straight line shown in the nomograph is referred to as an operation collinear L. As can be understood from this alignment chart, the difference (Ne) between the engine rotational speed Ne and the rotational speed Ns of the sun gear 32 with respect to the difference (Nr−Ns) between the rotational speed Nr of the ring gear 34 and the rotational speed Ns of the sun gear 32. -Ns) ratio (= (Ne-Ns) / (Nr-Ns)) is equal to the ratio of 1 to the value (1 + ρ) (= 1 / (1 + ρ)). Based on this proportional relationship, the above equation (1) is derived.

  Further, PM calculates MG1 command torque Tm1 *, which is the torque to be output to first generator motor MG1, according to the following equation (3) in this step (step 340). In the equation (3), the value PID (Nm1 * −Nm1) is a feedback amount corresponding to the difference between “MG1 target rotational speed Nm1 * and actual rotational speed Nm1 of the first generator motor MG1”. That is, the value PID (Nm1 * −Nm1) is a feedback amount for making the actual rotational speed Nm1 of the first generator motor MG1 coincide with the MG1 target rotational speed Nm1 *.

  Tm1 * = Te * · (ρ / (1 + ρ)) + PID (Nm1 * −Nm1) (3)

  Here, the basis of the above equation (3) will be described. When a torque equal to the target engine output torque Te * is generated on the crankshaft 25 (that is, when the engine output torque is Te *), the engine output torque Te * is torque-converted by the planetary gear unit 31. . As a result, the torque Tes expressed by the following equation (4) acts on the rotating shaft of the sun gear 32, and the torque Ter expressed by the following equation (5) acts on the rotating shaft of the ring gear 34.

Tes = Te * · (ρ / (1 + ρ)) (4)
Ter = Te * · (1 / (1 + ρ)) (5)

  In order for the operation collinearity to be stable, the force of the operation collinearity should be balanced. Therefore, as shown in FIG. 6, a torque Tm1 having the same magnitude and the opposite direction as the torque Tes obtained by the above equation (4) is applied to the rotating shaft of the sun gear 32, and the ring gear 34 is rotated. A torque Tm2 expressed by the following equation (6) may be applied to the shaft. That is, the torque Tm2 is equal to the shortage of the torque Ter with respect to the ring gear required torque Tr *. This torque Tm2 is adopted as the MG2 command torque Tm2 *.

  Tm2 = Tr * −Ter (6)

  On the other hand, if the sun gear 32 rotates at the target rotational speed Ns * (that is, if the actual rotational speed Nm1 of the first generator motor MG1 coincides with the MG1 target rotational speed Nm1 *), the engine rotational speed Ne becomes the target engine rotational speed. Matches speed Ne *. From the above, the MG1 command torque Tm1 * is obtained by the above equation (3).

Step 345:
PM calculates the MG2 command torque Tm2 *, which is the torque to be output to the second generator motor MG2, according to the above equations (5) and (6). PM may determine the MG2 command torque Tm2 * based on the following equation (7).

  Tm2 * = Tr * −Tm1 * / ρ (7)

Step 350:
The PM sends a command signal to the EG so that the engine 20 is operated at the optimum engine operating point (in other words, the engine output torque becomes the target engine output torque Te *). Thereby, the EG changes the opening degree of the throttle valve 22 by the throttle valve actuator 22a and also changes the fuel injection amount Fi to control the engine 20 so that the engine output torque Te becomes the target engine output torque Te *. .

Step 355:
PM transmits MG1 command torque Tm1 * to motor ECU 72. The motor ECU 72 controls the first inverter 61 so that the output torque of the first generator motor MG1 coincides with the MG1 command torque Tm1 *.

Step 360:
PM transmits MG2 command torque Tm2 * to motor ECU 72. The motor ECU 72 controls the second inverter 62 so that the output torque of the second generator motor MG2 matches the MG2 command torque Tm2 *.

  After performing the processing in step 335 to step 360, the PM proceeds to step 395 to end the present routine tentatively.

  Through the above-described processing, a torque equal to the ring gear required torque Tr * is applied to the ring gear 34 by the engine 20 and the second generator motor MG2. Further, when the charging rate SOC is smaller than the predetermined value SOCLOth, the output generated by the engine 20 is increased by the battery charge request output Pb *. Therefore, since the torque Ter acting on the rotating shaft of the ring gear 34 is increased, the MG2 command torque Tm2 * is decreased as understood from the above equation (6). As a result, the electric power consumed by the second generator motor MG2 out of the electric power generated by the first generator motor MG1 is reduced, so surplus power generated by the first generator motor MG1 (consumed by the second generator motor MG2). The battery 63 is charged by the electric power).

  The processing performed when the engine request output Pe * is equal to or greater than the threshold request output Peth has been described above. On the other hand, if the engine required output Pe * is smaller than the threshold required output Peth “less than”, the PM determines “No” in step 320 and proceeds to step 365 to check whether the engine 20 is currently operating. Determine whether or not.

  If the engine 20 is in operation, the PM determines “Yes” at step 365 and proceeds to step 370. In step 370, the PM determines whether intermittent operation is prohibited at this time. It should be noted that the engine 20 should not be driven from the viewpoint of the operating condition in which the engine required output Pe * is smaller than the threshold required output Peth (as described above, the optimum engine operating point of the engine 20 (FIG. 5)). (There is no operating condition. Accordingly, it is determined as “No” in step 320), the engine 20 may be operated as necessary (for example, a warm-up operation described later is performed). Case).

  Specifically, in step 370, for example, the PM determines whether or not the warm-up operation of the engine 20 is being performed, and whether or not the engine 20 needs to be operated in order to maintain the temperature of the catalysts 28a and 28b. No, whether the diagnosis (determination) of whether or not the fuel injection valve 24 is normally injecting fuel is executed, and the engine 20 needs to be operated in order to perform control different from this routine It is determined whether or not intermittent operation is prohibited based on whether or not there is (for example, learning of various operation parameters).

  If intermittent operation is prohibited at this time, the PM determines “Yes” in step 370 and proceeds to step 335. And PM performs the process of step 335-step 360 similarly to the above, and controls the output torque of the engine 20, the output torque of 1st generator motor MG1, and the output torque of 2nd generator motor MG2.

  On the other hand, if intermittent operation is not prohibited at this time, the PM determines “No” in step 370 and proceeds to step 375. In step 375, the PM transmits an instruction to stop the operation of the engine 20 to the EG. The EG stops the engine 20 by setting the fuel injection amount to zero based on this instruction (that is, by stopping the fuel injection). Thereafter, PM proceeds to step 380.

  On the other hand, if the engine 20 is stopped when the process of step 365 is performed, the PM determines “No” in step 365 and proceeds directly to step 380.

  In step 380, PM sets MG1 command torque Tm1 * to zero. Next, the PM proceeds to step 385 and sets the ring gear required torque Tr * to the MG2 command torque Tm2 *. Thereafter, the PM executes the processing of Step 355 and Step 360 described above. As a result, the ring gear required torque Tr * (and hence the user required torque Tu *) is satisfied only by the torque generated by the second generator motor MG2. Thereafter, the PM proceeds to step 395 to end this routine once.

  The above is the basic operation of the hybrid vehicle 10.

  By the way, in the hybrid vehicle 10, an overcurrent (for example, a specific circuit is long) is generated in a circuit for sequentially generating a magnetic field for rotating the rotor MG2r of the second generator motor MG2 with respect to the stator MG2s by a routine (not shown). When it is determined that current will continue to flow over time), current supply and interruption to the circuit is intermittently repeated in order to protect the circuit. As a result, the MG2 command torque Tm2 * may repeatedly increase and decrease intermittently (torque ripple phenomenon occurs).

  Therefore, when the misfire determination of the engine 20 is to be performed, the second device determines whether or not to actually perform the misfire determination depending on whether or not a condition for causing the torque ripple phenomenon is satisfied. ing. Details of the misfire determination performed by the second device will be described later.

<Actual operation>
Hereinafter, the actual operation of the second device will be described.

  In the second device, the EG repeatedly executes the routine shown in FIG. 7 for misfire determination at predetermined timings. Hereinafter, processing performed in this routine will be described.

  The EG repeatedly executes the “misfire determination routine” shown by the flowchart in FIG. 7 at every predetermined timing (for example, every time the crankshaft 25 rotates 30 °). By this routine, the EG determines whether or not the misfire determination is actually performed when the misfire determination is to be performed, and executes or prohibits the misfire determination according to the result of the determination.

  Specifically, when the EG starts processing from step 700 in FIG. 7 at a predetermined timing, the EG proceeds to step 705. In step 705, the EG determines whether or not the engine 20 is currently operating.

  If the engine 20 is currently operating, the EG makes a “Yes” determination at step 705 and proceeds to step 710. In step 710, the EG determines whether misfire determination should be performed at the present time. For example, the EG determines whether or not the engine 20 is currently warming up and whether or not the engine 20 needs to be operated in order to perform control different from this routine. Consider whether or not to make a misfire determination.

  If the EG determines that the misfire determination should be performed at the current time, the EG determines “Yes” in step 710 and proceeds to step 715. In step 715, the EG determines whether or not the MG2 command torque Tm2 * is not zero (Tm2 * ≠ zero).

  Here, when the current MG2 command torque Tm2 * is not zero (Tm2 * ≠ zero), the EG determines “Yes” in step 715, and determines whether the “condition for generating the torque ripple phenomenon” is satisfied. Determine whether. On the other hand, when the current MG2 command torque Tm2 * is zero (Tm2 * = zero), the EG makes a “No” determination at step 715 and appropriately executes the processing of steps 720 to 730 to determine whether or not there is a misfire. Check.

  More specifically, the EG is such that the vehicle speed SPD is equal to or lower than a predetermined threshold vehicle speed SPDth, the change rate ΔAP of the accelerator operation amount AP is equal to or lower than a predetermined threshold change rate ΔAP, and When the total amount STm2 * of the absolute value of the change amount of the MG2 command torque Tm2 * during the predetermined time length is equal to or greater than the threshold total amount STm2 * th, it is determined that the condition for causing the torque ripple phenomenon is satisfied. It is like that. This determination is performed by sequentially executing the processes in steps 735 to 745.

  If the engine 20 is not currently operating, and if the misfire determination should not be performed even if the engine 20 is currently operating, the EG determines “No” in step 705 or step 710. And the routine proceeds to step 795 to end the present routine tentatively. That is, in these cases, neither the confirmation of the torque ripple phenomenon nor the misfire determination is performed.

  Hereinafter, a case where “Yes” is determined in Step 715 (when the engine 20 is driven) will be described. If the EG determines “Yes” in step 715, the EG proceeds to step 735 and determines whether or not the current vehicle speed SPD is equal to or less than a predetermined threshold vehicle speed SPDth. When the magnitude of the vehicle speed SPD is equal to or less than the threshold vehicle speed SPDth, the threshold vehicle speed SPDth is “the rotor MG2r of the second generator motor MG2 is substantially stationary relative to the stator MG2s (or It is set to an appropriate value that can be determined as “moving at a speed equal to or lower than the minimum vehicle speed that can be measured by the vehicle speed sensor 85”. In other words, the threshold vehicle speed SPDth is set to an appropriate value (for example, 1 km / hour, etc.) that can determine that a torque ripple phenomenon may occur when the vehicle speed SPD is equal to or less than the threshold vehicle speed SPDth.

  If the current vehicle speed SPD is equal to or lower than the threshold vehicle speed SPDth, the EG makes a “Yes” determination at step 735 and proceeds to step 740. In step 740, the EG determines whether or not the change amount (change rate) ΔAP per unit time of the accelerator operation amount AP is equal to or less than a predetermined threshold change rate ΔAP. When the change rate ΔAP of the accelerator operation amount AP is equal to or less than the threshold change rate ΔAP, the threshold change rate ΔAP is “changes in the user requested torque Tu * (as described above, such as the target engine speed Ne * of the engine 20). The influence on the engine speed Ne is small enough to be ignored from the viewpoint of examining the presence or absence of the torque ripple phenomenon.

  When the change rate ΔAP of the accelerator operation amount AP is equal to or less than the threshold change rate ΔAP, the EG makes a “Yes” determination at step 740 and proceeds to step 745. In step 745, the EG determines whether or not the total amount STm2 * of the absolute value of the change amount of the MG2 command torque Tm2 * during a predetermined time length is equal to or greater than the threshold total amount STm2 * th. The threshold total amount STm2 * th is an appropriate value that can be determined that “the MG2 command torque Tm2 * varies due to the torque ripple phenomenon” when the total amount STm2 * is equal to or greater than the threshold total amount STm2 * th. Is set to

  If the total amount STm2 * is equal to or greater than the threshold total amount STm2 * th, the EG determines that the torque ripple phenomenon is occurring at the present time, determines “Yes” in step 745, and then proceeds to step 795. Proceed to end this routine once.

  Thus, when it is determined as “Yes” in all of Steps 735 to 745, the EG determines that a torque ripple phenomenon has occurred and does not perform misfire determination (the processing of Steps 720 to 730). .

  On the other hand, if “No” is determined in Step 715 and if “No” is determined in any of Steps 735 to 745, the EG proceeds to Step 720 and performs misfire determination.

  Specifically, in step 720, the EG determines whether or not the fluctuation amount ΔNe per unit time of the engine rotation speed Ne of the engine 20 is greater than or equal to the threshold fluctuation amount ΔNeth. The threshold fluctuation amount ΔNeth is set to an appropriate value at which it can be determined that a misfire has occurred in the engine 20 when the fluctuation amount ΔNe is equal to or greater than the threshold fluctuation amount ΔNeth. The method for obtaining the fluctuation amount ΔNe is not particularly limited, and a known method that takes into account the accuracy of misfire determination and the like can be employed.

  If the fluctuation amount ΔNe is equal to or greater than the threshold fluctuation amount ΔNeth at the present time, the EG determines “Yes” in step 720 and proceeds to step 725 to determine that a misfire has occurred. Thereafter, the EG proceeds to step 795 to end the present routine tentatively.

On the other hand, when the fluctuation amount ΔNe is smaller than the threshold fluctuation amount ΔNeth at the present time, the EG makes a “No” determination at step 720 to proceed to step 730 and determines that no misfire has occurred. Thereafter, the EG proceeds to step 795 to end the present routine tentatively.

As described above, in the second device, when it is determined that the torque ripple phenomenon has occurred in the second generator motor MG2 when the engine 20 is being driven, the misfire determination of the engine 20 is performed. Do not make misfire judgment even when it should be.
The above is the description of the second device.

<Summary of Embodiment>
As described with reference to FIGS. 1 to 7, the misfire determination device according to the embodiment of the present invention (the first device and the second device) is:
The internal combustion engine 20 having an output shaft 25 connected to the drive shaft 53 of the hybrid vehicle 10 so as to transmit torque, a rotor (rotor MG2r) connected to the drive shaft 53 so as to transmit torque, and a stator (stator MG2s) Is applied to the hybrid vehicle 10 including the electric motor MG2 including the motor MG2 and the misfire determination of the internal combustion engine 20 is performed based on the fluctuation ΔNe of the rotation speed of the output shaft 25 of the internal combustion engine 20.

Furthermore, the misfire determination device according to the embodiment of the present invention,
While the torque Tm2 * is output from the electric motor MG2 to the drive shaft 53, the rotor is substantially stationary with respect to the stator (the vehicle speed SPD is equal to or less than a threshold vehicle speed SPDth) and the internal combustion engine 20 is In the case of being driven, when a condition that causes a torque ripple phenomenon in which the torque output from the electric motor MG2 continuously increases and decreases is satisfied (determined as “Yes” in all of Steps 735 to 745 in FIG. 7). The misfire determination is prohibited (the processing in steps 720 to 730 in FIG. 7 is not performed).

In the misfire determination device according to the embodiment of the present invention,
The vehicle speed SPD of the hybrid vehicle 10 is equal to or lower than the threshold vehicle speed SPDth (determined as “Yes” in step 735 of FIG. 7), and the driving parameter (accelerator operation amount) used for determining the torque output from the electric motor MG2 AP) change rate ΔAP is equal to or less than the threshold change rate ΔAPth (determined as “Yes” in step 740 of FIG. 7), and the degree of variation STm2 * of the torque Tm2 * output from the electric motor MG2 is the threshold value. When the degree is not less than STm2 * th (when “Yes” is determined in step 745), a condition for causing the torque ripple phenomenon is satisfied.

  The present invention is not limited to the above embodiments, and various modifications can be adopted within the scope of the present invention.

  For example, in each of the above embodiments, when it is determined that the torque ripple phenomenon has occurred, the misfire determination itself is not performed. However, the misfire determination apparatus of the present invention is configured to perform the process for performing the misfire determination (steps 720 to 730 in FIG. 7) when the torque ripple phenomenon occurs, but ignore the result of the determination. obtain.

  Further, in each of the above embodiments, it is determined whether or not the torque ripple phenomenon has occurred in the second generator motor MG2. However, the misfire determination device of the present invention may be configured to determine whether or not the torque ripple phenomenon has occurred in the first generator motor MG1, and in both the first generator motor MG1 and the second generator motor MG2. It may be configured to determine whether or not a torque ripple phenomenon has occurred.

  In addition, the misfire determination device of the present invention may be configured to notify the operator of the engine 20 of the determination result when it is determined that a misfire has occurred in the engine 20, and measures against the misfire are provided. (For example, stopping the supply of fuel to the cylinder determined to have misfired).

  Furthermore, in the above embodiment, a spark ignition internal combustion engine is employed as the internal combustion engine 20 mounted on the hybrid vehicle 10. However, a compression ignition type internal combustion engine (diesel engine) can be adopted as an internal combustion engine mounted on a hybrid vehicle to which the misfire determination device of the present invention is applied.

  As described above, the present invention can be used as a misfire determination device in a hybrid vehicle including an internal combustion engine and an electric motor.

DESCRIPTION OF SYMBOLS 10 ... Hybrid vehicle, 20 ... Internal combustion engine, MG1 ... 1st generator motor, MG2 ... 2nd generator motor, MG2r ... Rotor (rotor), MG2s ... Stator (stator), 30 ... Power distribution mechanism, 50 ... Power Transmission mechanism, 53 ... drive shaft, 94 ... engine rotational speed sensor

Claims (2)

An internal combustion engine having an output shaft coupled to a drive shaft of the hybrid vehicle so as to transmit torque;
An electric motor having a rotor connected to the drive shaft so as to be able to transmit torque, and a stator;
And applied to hybrid vehicles with
A misfire determination apparatus that performs misfire determination of the internal combustion engine based on a change in rotational speed of the output shaft of the internal combustion engine,
While the torque is output from the electric motor to the drive shaft, the torque output from the electric motor continues when the rotor is substantially stationary with respect to the stator and the internal combustion engine is driven. A misfire determination device for a hybrid vehicle that prohibits the misfire determination when a condition that causes a torque ripple phenomenon that repeatedly increases and decreases is established. In the misfire determination apparatus of Claim 1,
The vehicle speed of the hybrid vehicle is less than or equal to a threshold vehicle speed, the change rate of the operating parameter used to determine the torque output from the electric motor is less than or equal to the threshold change rate, and the fluctuation of the torque output from the electric motor A hybrid vehicle misfire determination apparatus in which a condition for causing the torque ripple phenomenon is satisfied when the degree is equal to or greater than a threshold degree.

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