JP2014218115A - Series hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine control device for a series hybrid vehicle which enables fault diagnosis with the same accuracy as that for a conventional gasoline-powered vehicle without deteriorating power generation/charge performance and without reducing the chance of fault diagnosis.SOLUTION: A series hybrid vehicle is provided with engine control means controlling a power generation/charge amount so that an engine drive state is such that the engine generates a power generation/charge amount set as an operation condition for executing a system diagnosis and a power generation/charge amount allowing charging when SOC becomes equal to or less than a prescribed value for the first time during a driving cycle (from a present key switch ON to a next key switch ON), thereby to perform fault diagnosis without deteriorating the power generation/charge performance.

Description

  The present invention relates to a device for performing engine control of a series hybrid vehicle equipped with an engine and a drive motor, particularly a series hybrid vehicle using the engine only for power generation.

  As described in Patent Document 1, a series hybrid vehicle in which a vehicle is driven by a drive motor and an engine is used only for driving a generator is conventionally known. The series hybrid vehicle is configured to forcibly drive the engine to generate electric power when the SOC is low (hereinafter referred to as “forced power generation mode”) according to the amount of stored battery (hereinafter referred to as “SOC”). ) And a mode in which the engine is not stopped to generate power when the SOC is high (hereinafter referred to as “EV travel mode”), and when the SOC is intermediate between the two modes, depending on the accelerator operation amount and the vehicle speed. By switching and controlling the three driving (power generation) modes of driving the engine and adjusting the power generation amount (hereinafter referred to as “vehicle speed interlocking mode”), it is possible to achieve both improved fuel efficiency and drivability. Are known.

JP 2012-144138 A

  Unlike conventional gasoline vehicles, a series hybrid vehicle does not directly use an engine for driving a vehicle, but aims to supply necessary power to a battery or a drive motor according to the SOC and the running state of the vehicle. In other words, in a series hybrid vehicle, the engine is driven separately from the actual driver's operation (vehicle driving situation), and the amount of power generation is determined by the power of the generator, that is, the engine rotational speed. It is possible to keep the driving state of the engine in order to perform good power generation.

On the other hand, failure diagnosis (OBD: On Board Diagnosis) diagnoses failures such as deterioration and electrical failure of various sensors and actuators connected to the engine control device, such as electrical disconnection between the sensor and the engine control device. )is necessary. Among the failure diagnosis items, there is an item for performing failure diagnosis when the engine is in a determined driving state. For example, failure diagnosis of an air-fuel ratio sensor (O ₂ sensor) that measures the air-fuel ratio of exhaust gas can be mentioned.

  Of these air-fuel ratio sensor failure diagnoses, failure diagnosis that detects aging degradation of the sensor increases or decreases the fuel injection amount and alternately switches between rich and lean to vary the oxygen amount of the exhaust gas, thereby changing the air-fuel ratio sensor. The degree of aging deterioration of the sensor is detected by looking at the followability of the oxygen concentration detection amount. In order to accurately diagnose the degree of deterioration of the sensor over time, it is necessary to make the time from when the fuel injection amount is increased or decreased until the actual oxygen amount of the exhaust gas fluctuates to be constant. In other words, it is necessary to detect the aging of the sensor under certain operating conditions such as the intake air amount and the engine rotational speed.

In Patent Document 1, the travel (power generation) mode is switched according to the SOC. In particular, there is a vehicle speed-linked mode that simulates the engine drive of a gasoline vehicle. However, when the SOC increases or decreases, the vehicle speed-linked mode is deviated from the vehicle speed-linked mode. The driving (power generation) mode is switched.
In the EV traveling mode, failure diagnosis is not performed because the engine is stopped. Further, in the forced power generation mode, priority is given to engine control in which power generation efficiency and fuel efficiency are emphasized, and therefore, the engine drive state does not satisfy the condition for performing failure diagnosis for detecting aging deterioration of the sensor.

  For this reason, in the series hybrid vehicle, the chance of failure diagnosis by the engine control device is reduced as compared with the conventional gasoline vehicle. Furthermore, in a state where the series hybrid vehicle is charged to some extent (SOC is high), the engine start start target value (due to the decrease in SOC, the power to drive the drive motor is insufficient, the engine is started, and power generation (charging) is started. The engine is stopped until the SOC target value) is reached, and the vehicle can be driven by the drive motor. This reduces the chance of failure diagnosis of the engine control device.

  In the vehicle speed interlocking mode, the engine is driven according to the accelerator operation amount and the vehicle speed, so that the failure diagnosis can be performed when the driving state of the engine matches the condition for performing the failure diagnosis for detecting the aging deterioration of the sensor. However, if the SOC fluctuates and transitions to another mode such as EV driving mode or forced power generation mode, or the engine driving state fluctuates, the engine rotation speed fluctuates, and the engine driving state is If the condition for failure diagnosis for detecting aging deterioration is not met, the number of failure diagnosis is reduced. In addition, in order to increase the number of failure diagnosis, when the range of conditions for performing the failure diagnosis in which the engine driving state detects aged deterioration of the sensor is expanded (for example, the range of the engine rotation speed for performing the failure diagnosis is expanded), Since the fluctuation of the time from when the fuel injection amount is increased or decreased until the actual amount of oxygen in the exhaust gas fluctuates increases, there is a problem that the failure cannot be detected with the same accuracy as a conventional gasoline vehicle in the degree of deterioration of the sensor. is there.

  An object of the present invention is to eliminate the above-mentioned problems, and in a series hybrid vehicle, without impairing power generation (charging) performance, and without reducing the chance of failure diagnosis, with the same accuracy as a conventional gasoline vehicle. It aims at providing the hybrid vehicle provided with the engine control apparatus which can implement a failure diagnosis.

  The series hybrid vehicle according to the present invention includes an engine, a generator driven by the engine, a battery charged by the generator, and a drive for driving wheels by the generated power of the generator or the discharged power of the battery. A motor and an engine control device for controlling the engine, wherein the engine control device detects a storage amount of the battery and when the detected storage amount of the battery drops to a preset value. An engine start function for starting the engine, and starting the engine by the engine start function and starting supplying electric power to the battery and the drive motor by the generator, and a storage amount of the battery is preset. Failure diagnosis start determination function for determining failure diagnosis start when the value rises to It has a function to start a fault diagnosis when it is determined that the failure diagnosis starts by a constant function.

It is a figure which shows the drive system of the series hybrid vehicle which concerns on Embodiment 1 of this invention. It is an operation | movement image figure of SOC from the state fully charged by operation | movement of the engine control apparatus which performs the failure diagnosis which concerns on Embodiment 1. FIG. It is a flowchart which shows operation | movement of the engine control apparatus which performs the failure diagnosis which concerns on embodiment. It is a flowchart which shows the process order which starts the engine which concerns on embodiment of this invention. It is a flowchart which shows the process order which starts the failure diagnosis based on embodiment of this invention. It is a flowchart which shows the process order which completes the failure diagnosis based on embodiment of this invention. It is a flowchart which determines the failure diagnosis content according to SOC in the failure diagnosis which concerns on embodiment of this invention. It is an operation | movement image figure when SOC increases during failure diagnosis implementation based on Embodiment 2 of this invention. It is an operation | movement image diagram when SOC reduces during failure diagnosis implementation based on Embodiment 2 of this invention.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a drive system configuration of a series hybrid vehicle of the present invention. The drive system of the series hybrid vehicle includes an engine 1, a generator 3 driven by the engine 1, a battery 4 charged by the generator 3, and a drive motor that rotates by receiving power supply from the generator 3 and the battery 4. 5, a wheel including a left front wheel 6 </ b> L and a right front wheel 6 </ b> R connected to the drive motor 5, an engine control device 2 that controls the engine 1, and a vehicle control device 7 that controls the entire vehicle travel.

  FIG. 3 is a flowchart showing the operation of the engine control apparatus 2 that performs the failure diagnosis according to the embodiment of the present invention. FIG. 2 shows the operation of the SOC when the failure diagnosis is performed, and the vertical axis SOC (%) is shown on the horizontal axis, and time is shown on the horizontal axis. In FIG. 2, α, β, and γ are SOC level determination values. FIG. 4 is a flowchart of the engine control device 2 that determines whether or not to start the engine based on the SOC of the battery 4, and FIG. 5 determines whether or not a failure diagnosis is performed based on the SOC of the battery 4. FIG. 6 is a flowchart of the engine control device 2 that determines whether or not all the failure diagnosis has been completed by performing the failure diagnosis.

  Next, the operation of the engine control apparatus 2 according to the first embodiment of the present invention will be described with reference to the operation of the SOC of FIG. 2 and the flowcharts of FIGS. This operation is executed in the engine control device 2 at a constant time, for example, every 10 msec.

  FIG. 4 is an operation flowchart of the engine control device 2 that determines whether or not to start the engine based on the SOC of the battery 4. In FIG. 4, the engine 1 is started from a state where the engine 1 is stopped (engine stop). The operation of the engine control device 2 will be described. First, it is determined whether or not the engine 1 has been started (step S41). Since the engine is stopped this time (that is, NO), it is determined whether or not the SOC falls below a certain determination value α shown in FIG. 2 (SOC <determination value α) (step S45).

  In step S45, when the SOC falls below a certain determination value α (that is, YES), engine control device 2 starts engine 1 (engine start) (step S46).

  Next, in FIG. 4, the operation of the engine control device 2 when starting from a state where the engine 1 is started (engine start) will be described. First, in step S41, since the engine 1 is started (that is, YES), it is determined whether or not the SOC exceeds the determination value γ (determination value α <determination value γ) shown in FIG. 2 (SOC> γ). judge. (Step S42).

  In step S42, when the SOC exceeds the determination value γ (that is, YES), the engine control device 2 stops the engine (step S43). Next, in step S44, the vehicle travels by supplying power to the drive motor 5 using only the battery 4.

  FIG. 5 is an operation flowchart of the engine control device 2 for determining whether or not to perform failure diagnosis based on the SOC. In FIG. 5, the engine when the engine 1 is started from a state (engine start) is started. The operation of the control device 2 will be described. First, in step S51, since the engine 1 is started (that is, YES), the SOC is equal to or greater than the determination value β (determination value α <determination value β <determination value γ) shown in FIG. 2 (SOC ≧ β). Whether or not (step S52).

  In step S52, when the SOC becomes equal to or higher than the determination value β (that is, YES), the engine control device 2 permits the execution of failure diagnosis (step S53). On the other hand, when the SOC becomes less than the determination value β (that is, NO), the engine control device 2 does nothing and ends the operation.

  Next, referring to FIG. 5, the operation of the engine control device 2 when starting from a state where the engine 1 is stopped (engine stop) will be described. The engine control device 2 prohibits execution of failure diagnosis (step S54) because the engine 1 is stopped in step S51 (that is, NO).

  FIG. 6 is a flowchart of the engine control apparatus 2 that determines whether or not all the fault diagnosis has been completed by performing the fault diagnosis. In FIG. 6, a fault diagnosis (hereinafter referred to as “system system fault”) for detecting aged deterioration of various sensors. The operation of the engine control apparatus 2 when starting from a state in which all of the “diagnosis” is not completed will be described. First, in step S61, since the entire system failure diagnosis has not been completed (that is, NO), the engine control device 2 performs a system failure diagnosis of each sensor (step S63).

  Next, the operation of the engine control apparatus 2 when starting from the state where all system system failure diagnosis of various sensors has been completed will be described. First, in step S61, since the entire system failure diagnosis has been completed (that is, YES), the engine control apparatus 2 sets the initial system failure diagnosis to be completed (step S62).

  Next, the operation of the engine control device 2 according to the embodiment of the present invention will be described with reference to the contents obtained in FIGS. 4 to 6 and the operation of the SOC shown in FIG. 2 and the flowchart of FIG. To do.

  In FIG. 2, the operation of the engine control device 2 when starting from a state where the SOC of the battery 4 is high (fully charged), that is, starting from the EV traveling mode will be described. First, in step S31 of FIG. 3, since the SOC is in a high state, the engine 1 is in the engine stop state (that is, NO), so the engine control device 2 performs normal power generation control (step S35). carry out. This time, the EV running mode in which no power is generated is continued.

  Next, when time elapses and the SOC decreases, and time elapses until the timing of T21, the SOC becomes equal to or less than the determination value α (that is, YES in step S45) and the engine starts (step S46). In step S31, since the engine is started (that is, YES), the engine control device 2 determines whether or not failure diagnosis execution is permitted in the next step (step S32).

  Next, when the engine is started and the generator 3 is driven, the battery 4 is charged by the generator 3, so that the SOC increases. When the time elapses until the timing of T22, the SOC becomes equal to or greater than the determination value β (YES in step S52), and failure diagnosis execution permission (step S53) is permitted, in step S32, failure diagnosis permission (that is, YES) Therefore, the engine control device 2 determines whether or not the next initial failure diagnosis has not been completed (step S33).

  In step S33, immediately after the failure diagnosis execution permission, the initial failure diagnosis is not completed (step S63) (that is, YES), so the engine control device 2 performs the failure diagnosis. On the other hand, in step S33, when the initial failure diagnosis is completed (YES in step S61) with the passage of time, the initial failure diagnosis is completed (step S62) (that is, NO), and the engine control apparatus 2 is in a normal state. The power generation control (step S35) is performed (the forced power generation mode or the vehicle speed interlocking mode is performed depending on the SOC state), and the failure diagnosis is performed when the conditions for performing the failure diagnosis are met.

  Next, adjustment of the power generation (charging) amount of the generator 3 at the time of failure diagnosis will be described with reference to FIG. The operation after the timing when the elapsed time is T22 is the operation of the SOC when the failure diagnosis is performed. The vehicle control device 7 calculates a power generation amount that can be charged in the battery 4 from the power (hereinafter referred to as “discharge amount”) necessary for driving the drive motor 5 and the SOC, and calculates the power generation amount as information on the required power generation amount. Is sent to the engine control device 2 by a bus compliant with a standard such as CAN (Controller Area Network) (not shown).

  The engine control apparatus 2 calculates | requires the discharge amount as a vehicle from the request | requirement electric power generation (charge) amount and the state transition of SOC from the timing T21 to the timing T22. When this amount of discharge and the amount of power generation (charging) output by the engine 1 (hereinafter referred to as “engine required power generation amount”) are set to the same value, there is no fluctuation in the SOC.

  The engine control device 2 calculates the power generation amount that is the same or close to the power generation amount (charge) (hereinafter referred to as the engine power generation amount) (hereinafter referred to as the engine power generation amount) from the engine required power generation amount and the system system failure diagnosis of each sensor. , Referred to as “engine target power generation amount”), the intake air amount of the engine 1 is adjusted by a throttle valve (not shown) or the like, and the power generation amount of the generator 3 is controlled to become the engine target power generation amount.

  Next, after timing T22, the engine control device 2 estimates the amount of discharge of the vehicle according to the change in the SOC, and sets the engine required power generation amount from the estimated value. The engine target power generation amount is calculated from the engine required power generation amount as described in the previous paragraph, and the engine 1 is controlled.

  Since the engine control device 2 controls the engine 1 based on the engine target power generation amount, the SOC fluctuates in the vicinity of the determination value β after the timing T22, and the system failure diagnosis is performed without decreasing the SOC. It will be possible.

  According to the first embodiment, the system system failure diagnosis is performed in the process of generating (charging) by starting the engine, thereby reducing the chance of performing the failure diagnosis. In addition, by determining the amount of discharge as a vehicle and performing a fault diagnosis in the engine driving state where the amount of power generation (charging) is equivalent to the amount of discharging, power generation (charging) performance is not impaired, and conventional gasoline Fault diagnosis can be performed with the same accuracy as the vehicle.

Embodiment 2. FIG.
The vehicle system configuration of the second embodiment is the same as that in FIG. The operation of the engine control device 2 is different from that of the first embodiment. In the first embodiment, the SOC changes due to a large change in the amount of discharge of the vehicle due to an accelerator operation or the like during the execution of the system system fault diagnosis, so that control cannot be performed in the vicinity of the determination value β, and SOC <determination value α, Alternatively, SOC> determination value γ, and power generation (charging) performance may be impaired. The second embodiment relates to the operation of the engine control device 2 at this time. Hereinafter, FIGS. 7 to 9 will be described.

  FIG. 7 is a flowchart of the engine control apparatus 2 that determines an item to be subjected to failure diagnosis based on a change in the SOC. FIG. 8 is a diagram of the SOC when the discharge amount is decreased (the engine target power generation amount is decreased) by the accelerator operation. FIG. 9 shows the operation of the SOC when the discharge amount increases (the engine target power generation amount increases) by the accelerator operation. 8 and 9, the vertical axis indicates SOC (%), and the horizontal axis indicates time. Further, α, ε, β, δ, and γ are SOC determination values. The variation of the SOC will be described with reference to the operation of the SOC of FIGS. 8 and 9 and the flowchart of FIG.

  When the vehicle discharge amount decreases (engine target power generation amount decreases) at the timing of time T81 in FIG. 8, the SOC increases as shown after the timing of T81. In addition, when the discharge amount of the vehicle increases (the engine target power generation amount increases) at the timing of T91 in FIG. 9, the SOC decreases as shown after the timing of T91.

  Next, referring to FIG. 7, a flowchart of the engine control apparatus 2 that performs switching of failure diagnosis items when the SOC fluctuates as shown in FIGS. 8 and 9 will be described. This operation is executed in the engine control device 2 at a constant time, for example, every 10 msec.

  In FIG. 7, the operation of the engine control apparatus 2 when starting from the state of failure diagnosis execution permission (step S53) will be described. First, in step S71, since the failure diagnosis execution permission state is set (ie, YES), the process proceeds to the next step S72.

  Next, at the timing of time T81 in FIG. 8 with the passage of time, step S72 is a state where SOC is higher than determination value ε (determination value α <determination value ε <determination value β) (SOC> determination value ε) (that is, NO), and in the next step S74, when the SOC is lower than the determination value δ (determination value β <determination value δ <determination value γ) (SOC <determination value δ) (ie, NO), the SOC is Since it is stable and does not fluctuate, the failure diagnosis is performed as usual, that is, according to a predetermined order (step S76).

  Next, at the timing of time T82 in FIG. 8, in step S72, the SOC is higher than the determination value ε (SOC> determination value ε) (that is, NO), and in the next step S74, the SOC is determined to be the determination value δ. When the state is higher (SOC> determination value δ) (that is, YES), it is determined that the SOC has increased, and after the currently performed failure diagnosis is completed, the diagnosis item to be performed next is consumption. The diagnostic item (step S75) with high power is preferentially executed. As a diagnostic item with large power consumption, for example, there is an air-fuel ratio sensor (not shown). Since the air-fuel ratio sensor needs to be activated by raising the temperature of the sensor itself before diagnosis, an oil control valve (for driving a heater or changing a valve timing of a valve timing variable mechanism (not shown)) It is necessary to consume power to perform fault diagnosis such as driving a solenoid such as a purge valve (not shown) for supplying evaporated fuel gas generated in the fuel tank to the engine. There is.

  In step S75, the power consumption increases, and the SOC decreases as after the timing of time T83. At this time, when the SOC is lower than the determination value δ (SOC <determination value δ) (step S74 is NO), the failure diagnosis to be performed next is normal after the currently performed failure diagnosis is completed. As described above, that is, diagnosis is performed in accordance with a predetermined order (step S76).

  Next, at the timing of time T92 in FIG. 9, step S72 is in a state where SOC is lower than determination value ε (determination value α <determination value ε <determination value β) (SOC <determination value ε) (that is, YES). After determining that the SOC is decreasing and completing the currently performed failure diagnosis, the failure diagnosis item to be executed next is a diagnosis item with low power consumption (step S73), for example, the engine cooling water temperature (see FIG. Not shown). Since the engine cooling water temperature is only input and is a diagnostic item with low power consumption, it is preferentially executed.

  In step S73, the power consumption decreases, and the SOC increases as after the timing of time T93. At this time, when the SOC is higher than the determination value ε (SOC> determination value ε) (step S72 is NO), the failure diagnosis to be performed next time is normally performed after the currently performed failure diagnosis is completed. As described above, that is, diagnosis is performed in accordance with a predetermined order (step S76).

  According to the second embodiment, even when the amount of discharge of the vehicle changes greatly due to an accelerator operation or the like during failure diagnosis, and the SOC fluctuates greatly, SOC ≧ determination value α, SOC ≦ determination value γ Therefore, the failure diagnosis can be performed with the same accuracy as that of a conventional gasoline vehicle without impairing the power generation (charging) performance.

  Although the present invention has been described above with reference to the embodiments, the present invention can be combined with each other within the scope of the invention, and the embodiments can be appropriately modified or omitted.

DESCRIPTION OF SYMBOLS 1 engine, 2 engine control apparatus, 3 generator, 4 battery, 5 drive motor, 6L left front wheel, 6R right front wheel, 7 vehicle control apparatus.

  The present invention relates to a device for performing engine control of a series hybrid vehicle equipped with an engine and a drive motor, particularly a series hybrid vehicle using the engine only for power generation.

As described in Patent Document 1, a series hybrid vehicle in which a vehicle is driven by a drive motor and an engine is used only for driving a generator is conventionally known. The series hybrid vehicle is configured to forcibly drive the engine to generate electric power when the SOC is low (hereinafter referred to as “forced power generation mode”) according to the amount of stored battery (hereinafter referred to as “SOC”). ) And a mode in which the engine is not stopped to generate power when the SOC is high (hereinafter referred to as “EV travel mode”), and when the SOC is intermediate between the two modes, depending on the accelerator operation amount and the vehicle speed. By switching and controlling the three driving (power generation) modes of driving the engine and adjusting the power generation amount (hereinafter referred to as “vehicle speed interlocking mode”), it is possible to achieve both improved fuel efficiency and drivability. Are known.

JP 2012-144138 A

  Unlike conventional gasoline vehicles, a series hybrid vehicle does not directly use an engine for driving a vehicle, but aims to supply necessary power to a battery or a drive motor according to the SOC and the running state of the vehicle. In other words, in a series hybrid vehicle, the engine is driven separately from the actual driver's operation (vehicle driving situation), and the amount of power generation is determined by the power of the generator, that is, the engine rotational speed. It is possible to keep the driving state of the engine in order to perform good power generation.

On the other hand, failure diagnosis (OBD: On Board Diagnosis) diagnoses failures such as deterioration and electrical failure of various sensors and actuators connected to the engine control device, such as electrical disconnection between the sensor and the engine control device. )is necessary. Among the failure diagnosis items, there is an item for performing failure diagnosis when the engine is in a determined driving state. For example, failure diagnosis of an air-fuel ratio sensor (O ₂ sensor) that measures the air-fuel ratio of exhaust gas can be mentioned.

  Of these air-fuel ratio sensor failure diagnoses, failure diagnosis that detects aging degradation of the sensor increases or decreases the fuel injection amount and alternately switches between rich and lean to vary the oxygen amount of the exhaust gas, thereby changing the air-fuel ratio sensor. The degree of aging deterioration of the sensor is detected by looking at the followability of the oxygen concentration detection amount. In order to accurately diagnose the degree of deterioration of the sensor over time, it is necessary to make the time from when the fuel injection amount is increased or decreased until the actual oxygen amount of the exhaust gas fluctuates to be constant. In other words, it is necessary to detect the aging of the sensor under certain operating conditions such as the intake air amount and the engine rotational speed.

  In Patent Document 1, the travel (power generation) mode is switched according to the SOC. In particular, there is a vehicle speed-linked mode that simulates the engine drive of a gasoline vehicle. However, when the SOC increases or decreases, the vehicle speed-linked mode is deviated from the vehicle speed-linked mode. The driving (power generation) mode is switched. In the EV traveling mode, failure diagnosis is not performed because the engine is stopped. Further, in the forced power generation mode, priority is given to engine control in which power generation efficiency and fuel efficiency are emphasized, and therefore, the engine drive state does not satisfy the condition for performing failure diagnosis for detecting aging deterioration of the sensor.

  For this reason, in the series hybrid vehicle, the chance of failure diagnosis by the engine control device is reduced as compared with the conventional gasoline vehicle. Furthermore, in a state where the series hybrid vehicle is charged to some extent (SOC is high), the engine start start target value (due to the decrease in SOC, the power to drive the drive motor is insufficient, the engine is started, and power generation (charging) is started. The engine is stopped until the SOC target value) is reached, and the vehicle can be driven by the drive motor. This reduces the chance of failure diagnosis of the engine control device.

In the vehicle speed interlocking mode, the engine is driven according to the accelerator operation amount and the vehicle speed, so that the failure diagnosis can be performed when the driving state of the engine matches the condition for performing the failure diagnosis for detecting the aging deterioration of the sensor. However, if the SOC fluctuates and transitions to another mode such as EV driving mode or forced power generation mode, or the engine driving state fluctuates, the engine rotation speed fluctuates, and the engine driving state is If the condition for failure diagnosis for detecting aging deterioration is not met, the number of failure diagnosis is reduced. In addition, in order to increase the number of failure diagnosis, when the range of conditions for performing the failure diagnosis in which the engine driving state detects aged deterioration of the sensor is expanded (for example, the range of the engine rotation speed for performing the failure diagnosis is expanded), Since the fluctuation of the time from when the fuel injection amount is increased or decreased until the actual amount of oxygen in the exhaust gas fluctuates increases, there is a problem that the failure cannot be detected with the same accuracy as a conventional gasoline vehicle in the degree of deterioration of the sensor. is there.

  An object of the present invention is to eliminate the above-mentioned problems, and in a series hybrid vehicle, without impairing power generation (charging) performance, and without reducing the chance of failure diagnosis, with the same accuracy as a conventional gasoline vehicle. It aims at providing the hybrid vehicle provided with the engine control apparatus which can implement a failure diagnosis.

The series hybrid vehicle according to the present invention includes an engine, a generator driven by the engine, a battery charged by the generator, and a drive for driving wheels by the generated power of the generator or the discharged power of the battery. A motor and an engine control device for controlling the engine, wherein the engine control device detects a storage amount of the battery and when the detected storage amount of the battery drops to a preset value. An engine start function for starting the engine, and starting the engine by the engine start function and starting supplying electric power to the battery and the drive motor by the generator, and a storage amount of the battery is preset. Failure diagnosis start determination function for determining failure diagnosis start when the value rises to All SANYO having a function to start a fault diagnosis when it is determined that the failure diagnosis starts the constant function, the engine control device, battery charge levels γ and forced engine driving state battery charge levels of the engine stop state α Failure diagnosis is performed within the range of .

It is a figure which shows the drive system of the series hybrid vehicle which concerns on Embodiment 1 of this invention. It is an operation | movement image figure of SOC from the state fully charged by operation | movement of the engine control apparatus which performs the failure diagnosis which concerns on Embodiment 1. FIG. It is a flowchart which shows operation | movement of the engine control apparatus which performs the failure diagnosis which concerns on embodiment. It is a flowchart which shows the process order which starts the engine which concerns on embodiment of this invention. It is a flowchart which shows the process order which starts the failure diagnosis based on embodiment of this invention. It is a flowchart which shows the process order which completes the failure diagnosis based on embodiment of this invention. It is a flowchart which determines the failure diagnosis content according to SOC in the failure diagnosis which concerns on embodiment of this invention. It is an operation | movement image figure when SOC increases during failure diagnosis implementation based on Embodiment 2 of this invention. It is an operation | movement image diagram when SOC reduces during failure diagnosis implementation based on Embodiment 2 of this invention.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a drive system configuration of a series hybrid vehicle of the present invention. The drive system of the series hybrid vehicle includes an engine 1, a generator 3 driven by the engine 1, a battery 4 charged by the generator 3, and a drive motor that rotates by receiving power supply from the generator 3 and the battery 4. 5, a wheel including a left front wheel 6 </ b> L and a right front wheel 6 </ b> R connected to the drive motor 5, an engine control device 2 that controls the engine 1, and a vehicle control device 7 that controls the entire vehicle travel.

FIG. 3 is a flowchart showing the operation of the engine control apparatus 2 that performs the failure diagnosis according to the embodiment of the present invention. FIG. 2 shows the operation of the SOC when the failure diagnosis is performed, and the vertical axis SOC (%) is shown on the horizontal axis, and time is shown on the horizontal axis. In FIG. 2, α, β, and γ are SOC levels (battery storage amount levels) . FIG. 4 is a flowchart of the engine control device 2 that determines whether or not to start the engine based on the SOC of the battery 4, and FIG. 5 determines whether or not a failure diagnosis is performed based on the SOC of the battery 4. FIG. 6 is a flowchart of the engine control device 2 that determines whether or not all the failure diagnosis has been completed by performing the failure diagnosis.

  Next, the operation of the engine control apparatus 2 according to the first embodiment of the present invention will be described with reference to the operation of the SOC of FIG. 2 and the flowcharts of FIGS. This operation is executed in the engine control device 2 at a constant time, for example, every 10 msec.

FIG. 4 is an operation flowchart of the engine control device 2 that determines whether or not to start the engine based on the SOC of the battery 4. In FIG. 4, the engine 1 is started from a state where the engine 1 is stopped (engine stop). The operation of the engine control device 2 will be described. First, it is determined whether or not the engine 1 has been started (step S41). Since the engine is stopped (that is, NO) this time, it is determined whether or not the SOC is below a certain level α shown in FIG. 2 (SOC < level α) (step S45).

In step S45, when the SOC falls below a certain level α (that is, YES), engine control device 2 starts engine 1 (engine start) (step S46).

Next, in FIG. 4, the operation of the engine control device 2 when starting from a state where the engine 1 is started (engine start) will be described. First, in step S41, since the engine 1 is started (that is, YES), it is determined whether or not the SOC exceeds the level γ ( level α < level γ) shown in FIG. 2 (SOC> γ). (Step S42).

In step S42, when the SOC exceeds the level γ (that is, YES), the engine control device 2 stops the engine (step S43). Next, in step S44, the vehicle travels by supplying power to the drive motor 5 using only the battery 4.

FIG. 5 is an operation flowchart of the engine control device 2 for determining whether or not to perform failure diagnosis based on the SOC. In FIG. 5, the engine when the engine 1 is started from a state (engine start) is started. The operation of the control device 2 will be described. First, in step S51, since the engine 1 is started (that is, YES), it is determined whether or not the SOC is equal to or higher than the level β ( level α < level β < level γ) shown in FIG. 2 (SOC ≧ β). Determination is made (step S52).

In step S52, when the SOC becomes equal to or higher than the level β (that is, YES), the engine control device 2 permits the execution of failure diagnosis (step S53). On the other hand, when the SOC becomes lower than the level β (that is, NO), the engine control device 2 does nothing and ends the operation.

  Next, referring to FIG. 5, the operation of the engine control device 2 when starting from a state where the engine 1 is stopped (engine stop) will be described. The engine control device 2 prohibits execution of failure diagnosis (step S54) because the engine 1 is stopped in step S51 (that is, NO).

  FIG. 6 is a flowchart of the engine control apparatus 2 that determines whether or not all the fault diagnosis has been completed by performing the fault diagnosis. In FIG. 6, a fault diagnosis (hereinafter referred to as “system system fault”) for detecting aged deterioration of various sensors. The operation of the engine control apparatus 2 when starting from a state in which all of the “diagnosis” is not completed will be described. First, in step S61, since the entire system failure diagnosis has not been completed (that is, NO), the engine control device 2 performs a system failure diagnosis of each sensor (step S63).

  Next, the operation of the engine control apparatus 2 when starting from the state where all system system failure diagnosis of various sensors has been completed will be described. First, in step S61, since the entire system failure diagnosis has been completed (that is, YES), the engine control apparatus 2 sets the initial system failure diagnosis to be completed (step S62).

  Next, the operation of the engine control device 2 according to the embodiment of the present invention will be described with reference to the contents obtained in FIGS. 4 to 6 and the operation of the SOC shown in FIG. 2 and the flowchart of FIG. To do.

  In FIG. 2, the operation of the engine control device 2 when starting from a state where the SOC of the battery 4 is high (fully charged), that is, starting from the EV traveling mode will be described. First, in step S31 of FIG. 3, since the SOC is in a high state, the engine 1 is in the engine stop state (that is, NO), so the engine control device 2 performs normal power generation control (step S35). carry out. This time, the EV running mode in which no power is generated is continued.

Next, when time elapses and the SOC decreases, time elapses until the timing of T21, and the SOC becomes equal to or lower than the level α (that is, YES in step S45) and the engine starts (step S46). In step S31, since the engine is started (that is, YES), the engine control device 2 determines whether or not failure diagnosis execution is permitted in the next step (step S32).

Next, when the engine is started and the generator 3 is driven, the battery 4 is charged by the generator 3, so that the SOC increases. If the time elapses until the timing of T22 and the SOC becomes level β or more (YES in step S52) and the failure diagnosis execution permission is permitted (step S53), the failure diagnosis is permitted (that is, YES) in step S32. Therefore, the engine control device 2 determines whether or not the next initial failure diagnosis has not been completed (step S33).

  In step S33, immediately after the failure diagnosis execution permission, the initial failure diagnosis is not completed (step S63) (that is, YES), so the engine control device 2 performs the failure diagnosis. On the other hand, in step S33, when the initial failure diagnosis is completed (YES in step S61) with the passage of time, the initial failure diagnosis is completed (step S62) (that is, NO), and the engine control apparatus 2 is in a normal state. The power generation control (step S35) is performed (the forced power generation mode or the vehicle speed interlocking mode is performed depending on the SOC state), and the failure diagnosis is performed when the conditions for performing the failure diagnosis are met.

  Next, adjustment of the power generation (charging) amount of the generator 3 at the time of failure diagnosis will be described with reference to FIG. The operation after the timing when the elapsed time is T22 is the operation of the SOC when the failure diagnosis is performed. The vehicle control device 7 calculates a power generation amount that can be charged in the battery 4 from the power (hereinafter referred to as “discharge amount”) necessary for driving the drive motor 5 and the SOC, and calculates the power generation amount as information on the required power generation amount. Is sent to the engine control device 2 by a bus compliant with a standard such as CAN (Controller Area Network) (not shown).

  The engine control apparatus 2 calculates | requires the discharge amount as a vehicle from the request | requirement electric power generation (charge) amount and the state transition of SOC from the timing T21 to the timing T22. When this amount of discharge and the amount of power generation (charging) output by the engine 1 (hereinafter referred to as “engine required power generation amount”) are set to the same value, there is no fluctuation in the SOC.

  The engine control device 2 calculates the power generation amount that is the same or close to the power generation amount (charge) (hereinafter referred to as the engine power generation amount) (hereinafter referred to as the engine power generation amount) from the engine required power generation amount and the system system failure diagnosis of each sensor. , Referred to as “engine target power generation amount”), the intake air amount of the engine 1 is adjusted by a throttle valve (not shown) or the like, and the power generation amount of the generator 3 is controlled to become the engine target power generation amount.

  Next, after timing T22, the engine control device 2 estimates the amount of discharge of the vehicle according to the change in the SOC, and sets the engine required power generation amount from the estimated value. The engine target power generation amount is calculated from the engine required power generation amount as described in the previous paragraph, and the engine 1 is controlled.

Since the engine control device 2 controls the engine 1 based on the engine target power generation amount, the SOC fluctuates in the vicinity of the level β after the timing T22, and the system fault diagnosis can be performed without reducing the SOC. It becomes.

  According to the first embodiment, the system system failure diagnosis is performed in the process of generating (charging) by starting the engine, thereby reducing the chance of performing the failure diagnosis. In addition, by determining the amount of discharge as a vehicle and performing a fault diagnosis in the engine driving state where the amount of power generation (charging) is equivalent to the amount of discharging, power generation (charging) performance is not impaired, and conventional gasoline Fault diagnosis can be performed with the same accuracy as the vehicle.

Embodiment 2. FIG.
The vehicle system configuration of the second embodiment is the same as that in FIG. The operation of the engine control device 2 is different from that of the first embodiment. In the first embodiment, the SOC changes due to a large change in the amount of discharge of the vehicle due to an accelerator operation or the like during the execution of the system system failure diagnosis, and the control cannot be performed in the vicinity of the level β, and SOC < level α or SOC > Level γ, which may impair power generation (charging) performance. The second embodiment relates to the operation of the engine control device 2 at this time. Hereinafter, FIGS. 7 to 9 will be described.

FIG. 7 is a flowchart of the engine control apparatus 2 that determines an item to be subjected to failure diagnosis based on a change in the SOC. FIG. 8 is a diagram of the SOC when the discharge amount is decreased (the engine target power generation amount is decreased) by the accelerator operation. FIG. 9 shows the operation of the SOC when the discharge amount increases (the engine target power generation amount increases) by the accelerator operation. 8 and 9, the vertical axis indicates SOC (%), and the horizontal axis indicates time. Further, α, ε, β, δ, and γ are SOC levels (battery charge level) . The variation of the SOC will be described with reference to the operation of the SOC of FIGS. 8 and 9 and the flowchart of FIG.

  When the vehicle discharge amount decreases (engine target power generation amount decreases) at the timing of time T81 in FIG. 8, the SOC increases as shown after the timing of T81. In addition, when the discharge amount of the vehicle increases (the engine target power generation amount increases) at the timing of T91 in FIG. 9, the SOC decreases as shown after the timing of T91.

  Next, referring to FIG. 7, a flowchart of the engine control apparatus 2 that performs switching of failure diagnosis items when the SOC fluctuates as shown in FIGS. 8 and 9 will be described. This operation is executed in the engine control device 2 at a constant time, for example, every 10 msec.

  In FIG. 7, the operation of the engine control apparatus 2 when starting from the state of failure diagnosis execution permission (step S53) will be described. First, in step S71, since the failure diagnosis execution permission state is set (ie, YES), the process proceeds to the next step S72.

Next, at the timing of time T81 in FIG. 8 with the passage of time, step S72 is in a state where SOC is higher than level ε ( level α < level ε < level β) (SOC> level ε) (that is, NO), In the next step S74, when the SOC is lower than the level δ ( level β < level δ < level γ) (SOC < level δ) (that is, NO), the SOC does not change and is stable. Diagnosis is performed as usual, that is, failure diagnosis is performed according to a predetermined order (step S76).

Next, at the timing of time T82 in FIG. 8, in step S72, the SOC is higher than level ε (SOC> level ε) (ie, NO), and in the next step S74, SOC is higher than level δ ( When SOC> level [ delta]) state (that is, YES), it is determined that the SOC has increased, and after the currently executed failure diagnosis is completed, the diagnosis item to be executed next is a diagnosis with large power consumption. The item (step S75) is preferentially executed. As a diagnostic item with large power consumption, for example, there is an air-fuel ratio sensor (not shown). Since the air-fuel ratio sensor needs to be activated by raising the temperature of the sensor itself before diagnosis, an oil control valve (for driving a heater or changing a valve timing of a valve timing variable mechanism (not shown)) It is necessary to consume power to perform fault diagnosis such as driving a solenoid such as a purge valve (not shown) for supplying evaporated fuel gas generated in the fuel tank to the engine. There is.

In step S75, the power consumption increases, and the SOC decreases as after the timing of time T83. At this time, when the SOC is lower than the level δ (SOC < level δ) (step S74 is NO), the failure diagnosis to be performed next time is performed as usual after the currently performed failure diagnosis is completed. That is, diagnosis is performed according to a predetermined order (step S76).

Next, at the timing of time T92 in FIG. 9, in step S72, the SOC becomes lower (SOC < level ε) than the level ε ( level α < level ε < level β) (that is, YES), and the SOC decreases. After the completion of the currently executed failure diagnosis, the next failure diagnosis item to be executed is a diagnosis item with low power consumption (step S73), for example, engine coolant temperature (not shown) . Since the engine cooling water temperature is only input and is a diagnostic item with low power consumption, it is preferentially executed.

In step S73, the power consumption decreases, and the SOC increases as after the timing of time T93. At this time, when the SOC is higher than the level ε (SOC> level ε) (step S72 is NO), after the currently performed failure diagnosis is completed, the failure diagnosis to be performed next time is normal, That is, diagnosis is performed according to a predetermined order (step S76).

According to the second embodiment, even when the amount of discharge of the vehicle changes greatly due to an accelerator operation or the like during failure diagnosis and the SOC greatly changes, SOC ≧ level α and SOC ≦ level γ are satisfied. Therefore, it is possible to perform fault diagnosis with the same accuracy as that of a conventional gasoline vehicle without impairing the power generation (charging) performance.

  Although the present invention has been described above with reference to the embodiments, the present invention can be combined with each other within the scope of the invention, and the embodiments can be appropriately modified or omitted.

DESCRIPTION OF SYMBOLS 1 engine, 2 engine control apparatus, 3 generator, 4 battery, 5 drive motor, 6L left front wheel, 6R right front wheel, 7 vehicle control apparatus.

Claims (5)

  An engine, a generator driven by the engine, a battery charged by the generator, a drive motor for driving wheels by the generated power of the generator or the discharged power of the battery, and an engine for controlling the engine A control device, wherein the engine control device detects a storage amount of the battery and an engine start function that starts the engine when the detected storage amount of the battery drops to a preset value. When the engine is started by the engine starting function and the power supply to the battery and the drive motor is started by the generator, and when the storage amount of the battery rises to a preset value, failure diagnosis When the failure diagnosis start determination function for determining start and the failure diagnosis start determination function determines that failure diagnosis starts Series hybrid vehicle, characterized in that has a function to start the disabled diagnosis.   2. The series hybrid vehicle according to claim 1, wherein the engine control device performs a failure diagnosis within a range of a battery storage amount level γ in an engine stop state and a battery storage amount level α in an engine forced drive state.   In the engine control device, the battery charge level exceeds δ (where α <β <δ <γ) within the range of the battery charge level γ when the engine is stopped and the battery charge level α when the engine is forcibly driven. Priority is given to failure diagnosis that requires a large amount of power when the battery is in a state of failure, and failure diagnosis that requires only a small amount of power when the judgment level of the battery charge is lower than ε (where α <ε <β <δ). 2. The series according to claim 1, wherein it is determined that the fault diagnosis is possible in a predetermined order when the battery storage amount level is higher than ε and lower than δ. Hybrid vehicle.   The engine control device has a failure diagnosis control function for calculating an engine power generation request amount calculated by the vehicle control device and an engine target power generation amount that is an engine driving state necessary for the vehicle failure diagnosis, When adjusting the power generation amount calculated by the diagnostic control function and the power generation amount calculated by the power generation amount calculation function, the target engine rotation speed is obtained by calculation, and when the failure diagnosis start determination function determines the failure diagnosis start, The series hybrid vehicle according to claim 1, wherein a failure diagnosis is performed at an engine speed calculated by the engine control device.   A failure diagnosis item determination function for determining a failure diagnosis item according to a change amount of the battery storage amount calculated by the vehicle control device after starting the failure diagnosis by the failure diagnosis start determination function is provided. The series hybrid vehicle according to claim 4.

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