JP6465286B2 - Hybrid vehicle failure determination device - Google Patents

Description

  The present invention relates to a failure determination technique for an internal combustion engine of a hybrid vehicle.

In hybrid vehicles that have been developed in recent years, vehicles capable of traveling mode (series mode) in which a motor generator is driven by an internal combustion engine to generate electric power and driving wheels for traveling are driven only by an electric motor have been developed.
Further, in the hybrid vehicle capable of the above-described travel mode, a technology has been developed for determining a failure of the exhaust system detection means (air-fuel ratio sensor, oxygen concentration sensor, catalyst monitor, etc.) of the internal combustion engine in the travel mode. .

  For example, in Patent Document 1, the fuel supply to the internal combustion engine is stopped, so-called motoring is performed in which the internal combustion engine is forcibly driven by the motor generator, and the detection value of the intake / exhaust system detection means when the fuel supply stops is detected. A technique for determining a failure of the detection unit based on a change is disclosed.

Japanese Patent No. 4067001

Since the failure determination means of Patent Document 1 performs motoring for failure determination, the charging rate of the driving battery for the vehicle that supplies power to the motor generator decreases.
By the way, as a travel mode of the hybrid vehicle, an EV mode in which the engine is driven without being driven by an electric motor, a series mode in which the engine is driven to run while generating electric power while being driven, and an engine and an electric motor are both driven. A parallel mode for running and driving is known.

  Further, in a hybrid vehicle that can automatically select a plurality of these travel modes and automatically selects the vehicle, a vehicle having an operation device that changes the switching timing of the travel mode has been developed. For example, a normal mode and a mode selection switch for switching to a charging rate increase mode are provided. In the normal mode, the driving mode is selected based on an accelerator operation or the like while maintaining the charging rate of the driving battery within a predetermined range. In the charge rate increase mode, the travel mode in which the use of the EV mode is suppressed is selected so that the charge rate of the drive battery approaches full charge.

And in the hybrid vehicle provided with the operation device for changing the switching timing of the traveling mode, when the failure determination as described in Patent Document 1 is performed even though the charging rate increase mode is selected, There is a problem that the charging rate of the driving battery is lowered.
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a hybrid vehicle capable of suppressing a decrease in the charging rate of a driving battery due to a failure determination in a hybrid vehicle capable of mode selection. The object is to provide a vehicle failure determination device.

  In order to achieve the above object, the failure determination device for a hybrid vehicle of the present invention is driven by the internal combustion engine and can generate power, while the internal combustion engine is powered by electric power supplied from a drive battery mounted on the vehicle. A motor generator capable of driving the drive wheel, a drive motor for driving the drive wheels with electric power supplied from the drive battery, and a charge state detection means for detecting a charge rate of the drive battery, the motor The first driving mode in which the driving motor is driven by the electric power supplied from the driving battery while generating electricity by the generator and the driving by the electric power supplied from the driving battery after stopping the internal combustion engine A second driving mode in which the motor for driving is switched to maintain the charging rate of the driving battery within a predetermined normal use range. A hybrid vehicle having mode selection means for selecting a mode and a charging rate increase mode for increasing the charging rate of the driving battery to a predetermined charging rate by giving priority to the first traveling mode; Detecting means for detecting an exhaust component of the internal combustion engine; and motoring for temporarily stopping the fuel supply to the internal combustion engine by interrupting the first traveling mode and forcibly driving the internal combustion engine by the motor generator. Motoring execution means to be executed, detection value of the detection means when the motoring is executed and fuel supply to the internal combustion engine is stopped during the first traveling mode, and after the motoring is completed A failure determination means for determining a failure of the detection means based on a detection value of the detection means when the fuel supply is resumed, and whether the internal combustion engine is started Failure determination restricting means for restricting the failure determination by the failure determination means until a predetermined time elapses, and when the charging rate increase mode is selected than when the normal mode is selected Also, the predetermined time in the failure determination regulation means is set longer.

Preferably, when the normal mode is selected by the mode selection unit, the predetermined time in the failure determination regulation unit decreases as the charging rate detected by the charging state detection unit decreases. Should be set to be longer.
Preferably, the vehicle includes a plurality of the detection units, and the predetermined time in the failure determination regulation unit decreases as the number of the detection units that perform failure determination by the failure determination unit increases. It is good to set as follows.

Preferably, when the failure determination by the failure determination means does not start even after a predetermined period of time has elapsed since the vehicle was turned on, the predetermined time in the failure determination restriction means is set to be short.

  According to the hybrid vehicle failure determination device of the present invention, when the charging rate increase mode is selected, the motor is started after the internal combustion engine is started in the failure determination restricting means than when the normal mode is selected. Since the predetermined time during which the ring is regulated is set to be long, it is possible to prevent the motoring from being continuously executed after the start of the internal combustion engine or from the end of the motoring, and the charge rate of the drive battery due to the failure determination is reduced. The decrease can be suppressed. Therefore, failure determination can be performed without hindering the charging rate increase when the charging rate increase mode is selected.

1 is a schematic configuration diagram of a plug-in hybrid vehicle according to an embodiment of the present invention. It is a schematic block diagram of the intake / exhaust system of the engine of this embodiment. 7 is a part of a timing chart showing an example of control timing of various control signals in a failure determination method in series mode. It is the remainder of the timing chart which shows one Example of the control timing of the various control signals in the failure determination method in series mode.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a plug-in hybrid vehicle (hereinafter referred to as a vehicle 1) according to an embodiment of the present invention.
The vehicle 1 of the present embodiment can travel by driving the front wheels 3 by the output of the engine 2 (internal combustion engine), and also has an electric front motor 4 (drive motor) that drives the front wheels 3 (drive wheels) and a rear wheel. This is a four-wheel drive vehicle including an electric rear motor 6 (drive motor) that drives the wheels 5 (drive wheels).

The engine 2 can drive the drive shaft 8 of the front wheels 3 via the speed reducer 7 and can drive the motor generator 9 via the speed reducer 7 to generate electric power.
The front motor 4 is driven by being supplied with high-voltage power from the drive battery 11 and the motor generator 9 mounted on the vehicle 1 via the front inverter 10, and the drive shaft 8 of the front wheel 3 via the speed reducer 7. Drive. The speed reducer 7 incorporates a clutch 7 a capable of switching connection / disconnection of power between the output shaft of the engine 2 and the drive shaft 8 of the front wheel 3.

The rear motor 6 is driven by being supplied with high voltage power from the drive battery 11 and the motor generator 9 via the rear inverter 12, and drives the drive shaft 14 of the rear wheel 5 via the speed reducer 13.
The electric power generated by the motor generator 9 can charge the driving battery 11 via the front inverter 10 and can supply electric power to the front motor 4 and the rear motor 6.

The drive battery 11 is composed of a secondary battery such as a lithium ion battery, and has a battery module (not shown) configured by collecting a plurality of battery cells. Further, the battery module charge rate (State Of Charge, Hereinafter, a battery monitoring unit 11a (charging state detecting means) for monitoring SOC) and the like is provided.
The front inverter 10 includes a front motor control unit 10a and a generator control unit 10b. The front motor control unit 10 a controls the output of the front motor 4 based on a control signal from the hybrid control unit 20. The generator control unit 10 b has a function of controlling the power generation amount of the motor generator 9 based on a control signal from the hybrid control unit 20.

The rear inverter 12 has a rear motor control unit 12a. The rear motor control unit 12 a has a function of controlling the output of the rear motor 6 based on a control signal from the hybrid control unit 20.
Further, the motor generator 9 is supplied with electric power from the driving battery 11 based on a control signal from the hybrid control unit 20 and can drive the engine 2, and functions as a starter motor of the engine 2. Have

The vehicle 1 is also provided with a charger 21 that charges the drive battery 11 with an external power source.
The hybrid control unit 20 is a control device for performing comprehensive control of the vehicle 1 and includes an input / output device, a storage device (ROM, RAM, nonvolatile RAM, etc.), a central processing unit (CPU), and the like. Composed.

  On the input side of the hybrid control unit 20, a battery monitoring unit 11a of the driving battery 11, a front motor control unit 10a and a generator control unit 10b of the front inverter 10, a rear motor control unit 12a of the rear inverter 12, an engine control unit 22 ( A failure determination unit, a failure determination regulation unit), an accelerator opening sensor 40 for detecting an accelerator operation amount, a mode selection switch 46 (mode selection unit) to be described later, and the like are connected, and detection and operation information from these devices Is entered.

On the other hand, on the output side of the hybrid control unit 20, a front motor control unit 10a and a generator control unit 10b of the front inverter 10, a rear motor control unit 12a of the rear inverter 12, a speed reducer 7 (clutch 7a), and an engine control unit 22 are provided. It is connected.
The hybrid control unit 20 calculates a vehicle request output required for driving the vehicle 1 based on the various detection amounts and various operation information of the accelerator opening sensor 40 and the like, and the engine control unit 22, front motor Control signals are sent to the control unit 10a, the generator control unit 10b, the rear motor control unit 12a, and the speed reducer 7 to switch the running mode ((EV mode: electric vehicle mode), series mode, parallel mode), engine 2 and The outputs of the front motor 4 and the rear motor 6 and the output (generated power) of the motor generator 9 are controlled. Further, the hybrid control unit 20 has a function of performing motoring that is forcibly driven by the motor generator 9 without supplying fuel to the engine 2 (motoring execution means).

In the EV mode (second travel mode), the engine 2 is stopped, and the vehicle 1 is traveled by driving the front motor 4 and the rear motor 6 with electric power supplied from the drive battery 11.
In the series mode (first travel mode), the clutch 7 a of the speed reducer 7 is disconnected and the motor generator 9 is operated by the engine 2. Then, the front motor 4 and the rear motor 6 are driven to run by the electric power generated by the motor generator 9 and the electric power supplied from the driving battery 11. In the series mode, the rotation speed of the engine 2 is set to a predetermined rotation speed, and surplus power is supplied to the drive battery 11 to charge the drive battery 11.

In the parallel mode, the clutch 7 a of the speed reducer 7 is connected, and the power is mechanically transmitted from the engine 2 via the speed reducer 7 to drive the front wheels 3. Further, the front motor 4 and the rear motor 6 are driven to run by the electric power generated by operating the motor generator 9 by the engine 2 and the electric power supplied from the driving battery 11.
The hybrid control unit 20 sets the traveling mode to the parallel mode in an efficient region of the engine 2 such as a high speed region. Further, in the region excluding the parallel mode, that is, the middle / low speed region, the mode is switched between the EV mode and the series mode based on the charging rate SOC of the driving battery 11.

The hybrid control unit 20 further has a function of charging the driving battery 11 by forcibly driving the engine 2 to generate electric power when the charging rate SOC of the driving battery 11 falls below an allowable range.
In addition, the vehicle 1 of the present embodiment includes a mode selection switch 46 that selects the timing for switching the travel mode. The mode selection switch 46 is a switch that can be manually operated by the driver, and can be switched between the normal mode and the charging rate increase mode. As described above, the EV mode and the series mode are automatically switched based on the charging rate of the drive battery 11 or the like, but the mode selection switch 46 may change the timing (threshold) for switching the travel mode. it can. In the normal mode, the EV mode and the series mode are switched so that the charging rate of the drive battery 11 is maintained within a predetermined normal use range. In the charging rate increase mode, the EV mode and the series mode are switched so that the charging rate of the driving battery 11 increases to a predetermined charging rate close to full charge. That is, in the charging rate increase mode, the use of the EV mode that consumes the power of the driving battery 11 is suppressed.

FIG. 2 is a schematic configuration diagram of an intake / exhaust system of the engine 2.
As shown in FIG. 2, the intake passage 25 of the engine 2 of the present embodiment is provided with an air cleaner 26 that removes dust from the introduced intake air and a throttle valve 27 that controls the intake air flow rate.
The throttle valve 27 is controlled by the engine control unit 22 and controls the intake air flow rate by adjusting the flow passage area of the intake passage 25. Specifically, the flow path area is increased as the load (required output torque) of the engine 2 is increased, and the flow path area is decreased as the load is reduced.

The exhaust passage 31 of the engine 2 is provided with a main exhaust purification catalyst 32 and a warm-up exhaust purification catalyst 33.
The main exhaust purification catalyst 32 and the warm-up exhaust purification catalyst 33 are catalysts for purifying the exhaust of the engine 2, such as a known three-way catalyst.
The main exhaust purification catalyst 32 is a large-capacity catalyst so as to mainly perform exhaust purification, and is disposed, for example, under the floor of the vehicle 1. The warm-up exhaust purification catalyst 33 is a small-capacity catalyst, and is disposed on the upstream side of the main exhaust purification catalyst 32 and in the vicinity of the engine 2. When the engine temperature of the main exhaust purification catalyst 32 is low, such as when the engine 2 is started at a low temperature, the warm-up exhaust purification catalyst 33 immediately increases the catalyst temperature due to the exhaust of the engine 2 and improves the exhaust purification performance. Can be secured.

The engine 2 is provided with an EGR device 41 (exhaust gas recirculation device). The EGR device 41 includes an EGR passage 42 that recirculates exhaust gas to the intake passage 25, and an EGR valve 43 that is interposed in the EGR passage 42.
The EGR passage 42 communicates the exhaust passage 31 between the engine 2 and the warm-up exhaust purification catalyst 33 and the intake passage 25 between the engine 2 and the throttle valve 27.

The EGR valve 43 is controlled by the engine control unit 22 and controls the flow rate of the exhaust gas recirculated to the intake passage 25 by adjusting the flow area of the EGR passage 42.
The intake passage 25 between the connection portion of the EGR passage 42 and the engine 2 is provided with an intake pressure sensor 44 that detects the intake pressure Pa.

  The exhaust passage 31 between the engine 2 and the warm-up exhaust purification catalyst 33 is provided with a front O2 sensor 34 (detection means) for detecting the oxygen concentration (exhaust component) in the exhaust. The exhaust passage 31 between the warm-up exhaust purification catalyst 33 and the main exhaust purification catalyst 32 is provided with a rear O2 sensor 35 (detection means) for detecting the oxygen concentration in the exhaust. The front O2 sensor 34 and the rear O2 sensor 35 may be air-fuel ratio sensors that detect the air-fuel ratio.

The front O2 sensor 34 and the rear O2 sensor 35 output the detected oxygen concentration to the engine control unit 22 as a voltage value.
Further, the intake pressure sensor 44 outputs the detected intake pressure Pa to the engine control unit 22.
The engine control unit 22 is a control device for controlling the engine 2, and includes an input / output device, a storage device (ROM, RAM, nonvolatile RAM, etc.), a central processing unit (CPU), and the like. . The engine control unit 22 inputs detection values from various sensors such as a front O2 sensor 34, a rear O2 sensor 35, an intake pressure sensor 44, and a vehicle speed sensor 45 that detects the traveling speed of the vehicle 1, and a throttle valve 27, an EGR valve. 43 and a fuel injection valve (not shown) are controlled to perform air-fuel ratio control of the engine 2.

  Further, in the present embodiment, the engine control unit 22 has a failure determination function for the front O 2 sensor 34 and the rear O 2 sensor 35 and a failure determination function for the EGR valve 43. When it is determined by the failure determination function that any one of the front O2 sensor 34, the rear O2 sensor 35, and the EGR valve 43 has failed, the driver lights the warning light 36 provided in the driver's seat of the vehicle 1. Or control the fuel injection valve or the like so that the output of the engine 2 decreases.

  The failure determination of the exhaust system sensors (the front O2 sensor 34 and the rear O2 sensor 35) is performed in a state where the rotational speed of the drive shaft of the engine 2 is equal to or higher than a predetermined value and the fuel supply to the engine 2 is stopped. A failure determination is made based on the detection values of the O2 sensors 34 and 35 accompanying the stop of the fuel supply. In the parallel mode, the failure determination is performed when the fuel supply is stopped when the vehicle is decelerated. Furthermore, it is possible to determine the failure of each of the O2 sensors 34 and 35 even in the series mode.

  The failure determination of each of the O2 sensors 34 and 35 in the series mode is performed by stopping the fuel supply to the engine 2 while performing motoring for forcibly driving the engine 2 by the motor generator 9. These failure determinations can be made during engine stop motoring that is performed when shifting from the series mode to the EV mode in which the engine 2 is stopped, and during in-series motoring that is performed by interrupting the series mode.

3 and 4 are timing charts showing an embodiment of control timing of various control signals in the failure determination method in the series mode.
In this embodiment shown in FIGS. 3 and 4, motoring, engine low load operation, and fuel supply stop when the running mode is switched from the series mode to the EV mode, the series mode, the parallel mode, and the series mode in this order. The respective request timings are shown.

As shown in FIGS. 3 and 4, motoring is performed when the engine is stopped before switching from the series mode to the EV mode. In addition, during the series mode, the series mode is temporarily interrupted to perform motoring during the series. Further, in the present embodiment, during the series mode, a low load operation is performed and the failure determination of the EGR device 41 is performed.
In the present embodiment, one type of failure determination method for the front O2 sensor 34 and three types of failure determination methods for the rear O2 sensor 35 are executed at two timings: motoring during series and motoring when the engine is stopped. Specifically, the front O2 sensor response determination is executed for the front O2 sensor 34. For the rear O2 sensor 35, rear O2 sensor adhesion determination, rear O2 sensor slope determination, and rear O2 sensor response determination are performed. The failure determination of the exhaust system sensors 34 and 35 that perform motoring when the engine is stopped or motoring during the series by the engine control unit 22 corresponds to the failure determination means of the present invention.

The low load motoring request for failure determination shown in FIG. 3 represents the request timing and time of motoring and low load operation required in the failure determination of each exhaust system sensor 34, 35 and EGR valve 43. ON in 3 indicates that motoring or low load operation is requested.
Of the four types of failure determination methods of the exhaust system sensors 34 and 35, the front O2 sensor response determination is performed both when the air-fuel ratio in the exhaust gas changes from rich to lean and when the air fuel ratio changes from lean to rich. The time during which the detection value of the front O2 sensor 34 changes by a predetermined amount is measured, and it is determined whether or not the measurement time is equal to or greater than the threshold value T1. Is determined to be abnormal.

The rear O2 sensor sticking determination is performed to determine a state where the detection value of the rear O2 sensor 35 is stuck, that is, not changed at all, and an operation is performed in which the air-fuel ratio in the exhaust gas changes from rich to lean and from lean to rich. When the detected value of the rear O2 sensor 35 does not change at this time, it is determined that the rear O2 sensor 35 is in a fixed state and is in failure.
The rear O2 sensor slope determination is to determine the rate of change of the detection value of the rear O2 sensor 35. This determination is made when the air-fuel ratio in the exhaust gas changes from rich to lean. In this determination, the time when the detection value of the rear O2 sensor 35 changes the predetermined change amount in the intermediate region is measured, and it is determined whether or not the measurement time is equal to or greater than the threshold value T3. Is determined that the change rate of the rear O2 sensor 35 is abnormal.

  The rear O2 sensor response determination is to determine the rate of change of the detected value including the initial response of the rear O2 sensor 35. This determination is also made when the air-fuel ratio in the exhaust gas changes from rich to lean. . In this determination, the time when the detection value of the rear O2 sensor 35 changes from the fuel supply stop to a predetermined value is measured, and it is determined whether or not the measurement time is within the threshold value T4. The response of the rear O2 sensor 35 is determined to be abnormal.

  The EGR failure determination is to determine whether the EGR valve 43 is normally operated and exhaust gas recirculation is performed. The EGR valve 43 is opened and closed, and the intake pressure Pa changes with the opening and closing operation. It is determined by whether or not. If the intake pressure Pa changes by a predetermined value P1 or more with the opening / closing operation of the EGR valve 43, it is determined to be normal, and if there is no change or a change less than the predetermined value P1, it is determined to be abnormal.

  The stoichiometric F / B continuation timer is a timer that measures whether the stoichiometric operation state continues for a predetermined time Ta in the engine 2 and the air-fuel ratio in the exhaust is stable. From the start of series mode or the end of motoring during series By starting the timer and prohibiting the motoring operation until the predetermined time Ta elapses and restricting the failure determination, it is possible to determine the failure with high accuracy.

  The motoring request time is a motoring request time required according to the motoring request of each of the failure determination methods. The rear O2 sensor response determination threshold value T4 is longer than the other determination threshold values T1 and T3. Therefore, when the rear O2 sensor response determination is performed, the motoring request time is set to Tm1, and the rear O2 sensor response determination is performed. When a failure determination method other than the above is performed, the required motoring time is short and set to Tm2.

The motoring execution timer is a timer for setting a motoring execution time, starts measurement from the start of motoring, and ends motoring when the above motoring request time (Tm1 or Tm2) has elapsed.
The vehicle speed is the traveling speed of the vehicle 1 detected by the vehicle speed sensor 45. When the vehicle speed is equal to or less than the predetermined speed V1, failure determination of the exhaust system sensors 34 and 35 and the EGR valve 43 is restricted.

The in-series motoring prohibition timer shown in FIG. 4 is a timer for prohibiting the next motoring until a predetermined time T6 or T7 is measured after the completion of motoring.
The series medium / low load operation prohibition timer is a timer for prohibiting the low load operation from the start of the series operation until the predetermined time T8 is measured. The series medium and low load operation prohibition timer is also a timer for prohibiting the next low load operation from the time when the low load operation is completed and repaired until the measurement is performed for a predetermined time T9. The low load operation is prohibited until the measurement is started from the start of the series operation until the predetermined time T8 is measured, or until the measurement is started from the time when the low load operation is completed and the measurement is performed for the predetermined time T9.

The failure judgment operation request includes motoring when the engine is stopped, motoring during series, on condition that the restriction is released by the stoichiometric F / B continuation timer, series motoring prohibition timer, and series medium / low load operation prohibition timer. Indicates an operation request for low-load operation.
The fuel determination request fuel cut is turned on from the motoring request start timing input from the hybrid control unit 20 until the motoring execution timer reaches the motoring request time (Tm1 or Tm2), and the fuel supply is stopped. To do.

The HEV required combustion torque is an output torque of the engine 2 required from the hybrid control unit 20.
The EGR monitor completion determination indicates whether or not the failure determination of the EGR valve 43 has been completed, and is turned on when the failure determination ends, and is turned off when the vehicle power is turned off or when the engine 2 is stopped.
In the engine stall mode, the state where the drive shaft of the engine 2 is stopped is turned on, and the state where the drive shaft is rotating is turned off.

  In this embodiment, when the failure determination of the front O2 sensor 34 and the rear O2 sensor 35 is performed in the series mode, when the engine is stopped at the time of switching from the series mode to the EV mode, and during the motoring in the series The failure determination is possible in both cases, and among these motoring, the failure determination is performed at the time of motoring suitable for each failure determination method.

  The failure determination at the time of motoring in the series is based on the fact that the motor generator 9 forcibly drives the engine 2 while stopping the fuel supply to the engine 2 and the richness of the oxygen concentration (or air-fuel ratio) in the exhaust. When a change to lean is detected to determine whether the front O2 sensor 34 and the rear O2 sensor 35 have failed, and when the fuel supply to the engine 2 is resumed when returning from motoring to series operation, A change in the oxygen concentration (or air-fuel ratio) from lean to rich is detected, and failure determination of the front O2 sensor 34 and the rear O2 sensor 35 is performed. Thereby, in the failure determination at the time of motoring during the series, if the motoring time can be secured, all the failure determination methods described above can be executed.

In addition, failure determination during motoring when the engine is stopped is a failure determination method that is possible when the air-fuel ratio in the exhaust gas changes from rich to lean, and the slope determination and response determination of the rear O2 sensor 35 are possible. Become.
In the present embodiment, during the series motoring, the front O2 sensor response determination that cannot be determined when the engine is stopped is performed, and when the engine is stopped when switching to the EV mode, any motoring is performed. A rear O2 sensor slope determination and a rear O2 sensor response determination that can determine a failure are performed.

  The EGR failure determination is performed during low load operation in which the power generation load of the motor generator 9 is reduced during the series mode. Specifically, when the EGR failure determination is performed, the generated power of the motor generator 9 is reduced, and the HEV required combustion torque is set to a second predetermined torque N2 lower than the first predetermined torque N1 that is normally set during series operation. Set. At this time, the engine rotational speed becomes a second predetermined rotational speed R2 lower than the first rotational speed R1 normally set in the series mode. Note that, during the series motoring and the motoring when the engine is stopped, the engine rotation speed is set to a third rotation speed R lower than the second rotation speed R2.

As shown in FIG. 4, when the EV mode is switched to the series mode, the series medium / low load operation prohibition timer counts down from the predetermined value T8, and when it becomes 0, the vehicle speed is equal to or higher than the predetermined speed V1. A failure determination of the EGR valve 43 is performed.
The failure determination of the EGR valve 43 is performed by opening / closing the EGR valve 43 as described above, and determining whether or not the intake pressure Pa changes with the opening / closing operation. For example, three times), and it is determined that only when all change by a predetermined value P1 or more, it is normal. The EGR monitor completion determination counts the number of times that the intake pressure Pa has changed by a predetermined value P1 or more. If it is performed a predetermined number of times, it is turned on, and the EGR failure determination is completed.

Furthermore, in the present embodiment, the predetermined time Ta, which is a threshold value for restriction determination in the stoichiometric F / B continuation timer, is changed based on the operation of the mode selection switch 46. When the charging rate increase mode is selected by the mode selection switch 46, the predetermined time Ta of the stoichiometric F / B continuation timer is set longer than when the normal mode is selected.
Thus, in this embodiment, the predetermined time Ta of the stoichiometric F / B continuation timer, which is the time during which motoring is restricted from engine startup, is set longer when the charging rate increase mode is selected. It is possible to suppress the motoring from being performed immediately after the start, and to suppress a decrease in the charging rate of the driving battery 11. On the other hand, in the normal mode, by setting the predetermined time Ta of the stoichiometric F / B continuation timer to be short, motoring is executed immediately after the engine is started, and the failure determination of the exhaust system sensors 34 and 35 can be quickly performed. it can.

  Furthermore, the predetermined time Ta of the stoichiometric F / B continuation timer may be set based on the charging rate of the driving battery 11. Specifically, when the engine control unit 22 sets the predetermined time Ta of the stoichiometric F / B continuation timer when starting the engine, the engine control unit 22 inputs the charging rate of the driving battery 11 immediately after starting the engine from the battery monitoring unit 11a. The predetermined time Ta is set longer as the rate decreases.

Thus, by setting the predetermined time Ta of the stoichiometric F / B continuation timer based on the charging rate of the driving battery 11, when the charging rate is lowered, the predetermined time Ta is lengthened and motoring is performed. The charging rate can be reliably prevented from lowering due to the failure determination.
Further, in this embodiment, as a failure determination for performing the motoring, a failure determination of two detection means of the front O2 sensor 34 and the rear O2 sensor 35 is performed, a front O2 sensor response determination, a rear O2 sensor slope determination, and a rear O2 sensor. Although there are a plurality of failure determinations such as response determination, the predetermined time Ta of the stoichiometric F / B continuation timer is shortened as the number of detection means for determining these failures or the number of failure determination requests increases at the same time. It is good to set as follows.

As a result, when there are a large number of failure determination detection means or failure determination requests, the predetermined time Ta of the stoichiometric F / B continuation timer is shortened to enable motoring immediately after the engine is started. Therefore, the failure determination is started early from the start of the engine, and a plurality of failure determinations can be completed early.
Further, the engine control unit 22 measures a time Tb from READY-ON (power on) of the vehicle 1 and the failure determination is not executed even when the measurement time Tb has passed the predetermined time T10 (predetermined period). For this, the predetermined time Ta of the stoichiometric F / B continuation timer may be further shortened.

As a result, when failure determination is not made even after a predetermined time T10 from READY-ON has elapsed, the predetermined time Ta of the stoichiometric F / B continuation timer is shortened to enable motoring more quickly and ensure failure determination. Can be started.
In addition, this invention is not limited to the said embodiment. For example, the hybrid control unit 20 may perform various types of failure determination, failure determination regulation, and various types of control associated with failure determination. Further, in the present embodiment, the present invention is applied to a plug-in hybrid vehicle that can be switched between the EV mode, the series mode, and the parallel mode. However, as in the series mode, a driving mode in which a motor generator is driven by the engine to generate electric power. In addition, a travel mode in which driving wheels are driven by an electric motor as in the EV mode is possible, and the present invention can be widely applied to hybrid vehicles that can change the travel mode switching timing.

1 Vehicle (hybrid vehicle)
2 Engine (Internal combustion engine)
4 Front motor (drive motor)
6 Rear motor (drive motor)
9 motor generator 11 drive battery 11a battery monitoring unit (charge state detection means)
20 Hybrid control unit (Motoring execution means)
22 Engine control unit (failure judgment means, failure judgment regulation means)
34 Front O2 sensor 34 (detection means)
35 Rear O2 sensor 35 (detection means)
46 Mode selection switch (Mode selection means)

Claims (4)

An internal combustion engine mounted on a vehicle, a motor generator driven by the internal combustion engine and capable of generating electric power while driving the internal combustion engine with electric power supplied from a driving battery mounted on the vehicle, and the drive A drive motor for driving the drive wheels with electric power supplied from the battery for battery, and a charge state detection means for detecting a charge rate of the drive battery,
A first traveling mode in which the motor is driven by the electric power supplied from the driving battery while generating electricity with the motor generator, and the electric power supplied from the driving battery after stopping the internal combustion engine. Priority is given to the normal mode in which the charge rate of the drive battery is maintained within a predetermined normal use range by switching between the second travel mode in which the drive motor is driven to travel and the first travel mode. A charge rate increasing mode for increasing the charging rate of the driving battery to a predetermined charging rate is provided in a hybrid vehicle including mode selection means for selecting,
Detecting means for detecting an exhaust component of the internal combustion engine;
Motoring execution means for interrupting the first traveling mode to temporarily stop fuel supply to the internal combustion engine and for executing motoring for forcibly driving the internal combustion engine by the motor generator;
The detection value when the motoring is executed during the first traveling mode to stop the fuel supply to the internal combustion engine, and when the fuel supply is restarted after the motoring is completed A failure determination unit that determines a failure of the detection unit based on a detection value of the detection unit;
Failure determination restriction means for restricting the failure determination by the failure determination means until a predetermined time has elapsed since the start of the internal combustion engine,
The failure determination device for a hybrid vehicle, wherein the predetermined time in the failure determination restriction means is set longer when the charging rate increase mode is selected than when the normal mode is selected. . When the normal mode is selected by the mode selection unit, the predetermined time in the failure determination regulation unit becomes longer as the charging rate detected by the charging state detection unit decreases. The failure determination device for a hybrid vehicle according to claim 1, wherein the failure determination device is set. The vehicle includes a plurality of the detecting means,
3. The predetermined time in the failure determination regulation unit is set to be shortened as the number of the detection units that perform failure determination by the failure determination unit increases. Hybrid vehicle failure determination device. When the failure determination by the failure determination unit does not start even after a predetermined period of time has elapsed since the vehicle was turned on, the predetermined time in the failure determination regulation unit is set to be shortened. Item 4. The hybrid vehicle failure determination device according to any one of Items 1 to 3.

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