Vehicle control device

Abstract

To suppress hindrance to the traveling of a vehicle when the charging of a power storage device is restricted.SOLUTION: When an engine is in a state of being restricted in output, driving force by an electric motor in assistance control is restricted, irrespective of the amount of charge in a power storage device. As a result, while the charging of the power storage device by the electric motor is restricted due to the output restriction of the engine, power consumption by the electric motor is suppressed due to the restriction in the assistance control, so that a reduction in the amount of charge in the power storage device is suppressed, thereby facilitating the execution of subsequent assistance control. Accordingly, it is possible to suppress hindrance to the traveling of a vehicle when the charging of the power storage device is restricted.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a control device for a vehicle having an engine and an electric motor as driving power sources. [Background technology]

[0002] There are well-known control devices for vehicles that include an engine as a driving force source, an electric motor as the driving force source that is a generator that generates electricity using the power of the engine, and an electricity storage device that supplies and receives electricity to and from the electric motor. For example, there is a motor assist control device for a hybrid vehicle described in Patent Document 1. Patent Document 1 discloses that, when the vehicle accelerates, only when the accelerator opening is large, a decision is made as to whether to permit or prohibit assist control by the electric motor, which applies the motor torque of the electric motor to the drive wheels in addition to the engine torque, based on the discharge power of the electricity storage device, which is based on the charge amount of the electricity storage device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-100473 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when determining whether or not to perform assist control by the electric motor based on the drive demand amount for the vehicle and the charge amount of the power storage device, there is a possibility that the charge amount of the power storage device will decrease to a predetermined charge amount at which assist control becomes impossible by executing assist control. At this time, if the power storage device is in a state where it cannot be charged or where it is difficult to charge, it becomes difficult to return the power storage device from the state where the charge amount has decreased to a state where assist control by the electric motor is possible, and it becomes difficult to implement the assist control thereafter, which may cause an impediment to vehicle driving.

[0005] The present invention has been made against the background of the above circumstances, and its object is to provide a vehicle control device that can suppress interference with vehicle driving when charging of a power storage device is restricted. [Means for solving the problem]

[0006] The gist of a first aspect of the present invention is a control device for a vehicle including: (a) an engine as a driving force source; an electric motor as the driving force source, which is a generator generating electricity using power from the engine; and an electricity storage device that supplies and receives electric power to the electric motor, (b) including an electric motor control unit that performs assist control by the electric motor to apply driving force by the electric motor to driving wheels in addition to driving force by the engine so as to realize a driving request amount for the vehicle when there is a request for acceleration by a driver; and (c) when the engine is in an output-limited state, the electric motor control unit limits the driving force by the electric motor in the assist control regardless of the charge amount of the electricity storage device. (d) the motor control unit terminates the assist control each time the assist control is performed when the energy consumed by the electric motor in the assist control exceeds a predetermined energy for suppressing a decrease in the charge amount of the power storage device or heat generation of the power storage device; (e) the motor control unit limits the driving force of the electric motor in the assist control by setting the predetermined energy to zero or to a value smaller than that when the engine is in a state where the output is not limited; (f) the motor control unit changes the predetermined energy based on at least one of a state of the driver's intention to accelerate and a state of output responsiveness of the engine; and (g) the motor control unit increases the predetermined energy when the driver's intention to accelerate is high compared to when the intention is low, and increases the predetermined energy when the output responsiveness of the engine is low compared to when the output responsiveness is high. The point is...

[0010] Also, 2 The invention The gist of the present invention is that the present invention provides a control device for a vehicle including: (a) an engine as a driving force source; an electric motor as the driving force source, which is a generator that generates electricity using the power of the engine; and an electricity storage device that supplies and receives electric power to the electric motor, (b) including an electric motor control unit that performs assist control by the electric motor to provide driving force by the electric motor to driving wheels in addition to driving force by the engine so as to realize a driving request amount for the vehicle when there is a request for acceleration by a driver; (c) when the engine is in an output-limited state, the electric motor control unit limits the driving force by the electric motor in the assist control regardless of the charge amount of the electricity storage device; and (d) the electric motor control unit terminates the assist control when a duration from a start point of the assist control exceeds a predetermined time for suppressing a decrease in a charge amount of the power storage device or heat generation of the power storage device, each time the assist control is performed, (e) The motor control unit limits the driving force of the electric motor in the assist control by setting the specified time to zero or making it shorter than when the engine is in a state where output is not limited.

[0011] Also, 3 The present invention relates to the 2In the vehicle control device described in the invention, the motor control unit changes the specified time based on at least one of the state of the driver's intention to accelerate and the state of the engine's output responsiveness, and the motor control unit makes the specified time longer when the driver's intention to accelerate is high compared to when it is low, and longer when the engine's output responsiveness is low compared to when it is high. Effect of the Invention

[0012] According to the first aspect of the present invention, when the engine is in an output-limited state, the driving force of the electric motor in the assist control is limited regardless of the charge amount of the power storage device, so that while the charging of the power storage device by the electric motor is limited due to the engine output being limited, the power consumption by the electric motor is suppressed due to the limitation in the assist control, and the decrease in the charge amount of the power storage device is suppressed, making it easier to implement the subsequent assist control. Therefore, it is possible to suppress interference with vehicle travel when the charging of the power storage device is limited. According to the first aspect of the present invention, the assist control is terminated each time the assist control is performed if the energy consumed by the electric motor exceeds a predetermined energy for suppressing a decrease in the charge amount of the power storage device or heat generation of the power storage device, so that it is possible to suppress a situation in which the assist control is difficult to perform due to a decrease in the charge amount of the power storage device or heat generation of the power storage device caused by the execution of the assist control. In the control in which the assist control is terminated when the energy consumed by the electric motor exceeds the predetermined energy, no limitation is imposed on the assist control immediately after the start of acceleration, so that a secondary effect is obtained in that the assist control can be effectively performed during a period in which the rise of the engine torque is slow immediately after an acceleration operation, for example. In addition, the predetermined energy is set to zero or is smaller than when the engine is in a state in which the output is not limited, so that the driving force of the electric motor in the assist control is limited, and therefore the power consumption by the electric motor is appropriately suppressed and the decrease in the charge amount of the power storage device is appropriately suppressed. According to the first aspect of the present invention, the predetermined energy is set to be larger when the driver's intention to accelerate is high than when it is low, and larger when the engine output responsiveness is low than when it is high, so that when the driver's intention to accelerate is high, i.e., the driver is considered to place more importance on the acceleration feeling, or when the engine output responsiveness is low and a larger driving force from the electric motor is required to improve the acceleration feeling, the implementation time of the assist control is relatively long, making it easier to improve the driving feeling. When the driver's intention to accelerate is low, or when the engine output responsiveness is high, the implementation time of the assist control is relatively short, making it easier to suppress energy consumption.

[0016] According to the second aspect of the present invention, when the engine is in an output-limited state, the driving force of the electric motor in the assist control is limited regardless of the charge amount of the power storage device, so that while the charging of the power storage device by the electric motor is limited due to the engine output being limited, the power consumption by the electric motor is suppressed due to the limitation in the assist control, and the decrease in the charge amount of the power storage device is suppressed, making it easier to implement the subsequent assist control. Therefore, it is possible to suppress interference with vehicle travel when the charging of the power storage device is limited. In addition, 2According to the invention, when the duration from the start of the assist control exceeds a predetermined time for suppressing a decrease in the charge amount of the power storage device or heat generation of the power storage device, the assist control is terminated each time the assist control is performed, so that it is possible to suppress a decrease in the charge amount of the power storage device or heat generation of the power storage device due to the execution of the assist control, which makes it difficult to perform the subsequent assist control. In the control in which the assist control is terminated when the duration from the start of the assist control exceeds a predetermined time, no limitation is imposed on the assist control immediately after the start of acceleration, so that a secondary effect is obtained in that the assist control can be effectively applied during a period in which the rise of the engine torque is slow immediately after an acceleration operation, for example. In addition, by setting the predetermined time to zero or to a shorter time than when the engine is not in a state in which the output is limited, the driving force of the electric motor in the assist control is limited, so that the power consumption by the electric motor is appropriately suppressed and the decrease in the charge amount of the power storage device is appropriately suppressed.

[0017] In addition, 3 According to the invention, the predetermined time is set longer when the driver's intention to accelerate is high than when it is low, and longer when the engine output responsiveness is low than when it is high, so that when the driver's intention to accelerate is high, where the driver is considered to place more importance on the acceleration feeling, or when the engine output responsiveness is low and a larger driving force from the electric motor is required to improve the acceleration feeling, the implementation time of the assist control is relatively long, making it easier to improve the driving feeling. When the driver's intention to accelerate is low, or when the engine output responsiveness is high, the implementation time of the assist control is relatively short, making it easier to suppress energy consumption. [Brief description of the drawings]

[0018] [Figure 1] 1 is a diagram illustrating a schematic configuration of a vehicle to which the present invention is applied, and is also a diagram illustrating main parts of control functions and a control system for various controls in the vehicle. [Diagram 2] FIG. 4 is a diagram illustrating MG assist control. [Diagram 3] 4 is a flowchart illustrating a main part of the control operation of the electronic control device, and is a flowchart illustrating the control operation for suppressing interference with vehicle driving when charging of the battery is restricted. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. EXAMPLES

[0020] Fig. 1 is a diagram illustrating a schematic configuration of a vehicle 10 to which the present invention is applied, and also illustrates the main parts of the control functions and control system for various controls in the vehicle 10. In Fig. 1, the vehicle 10 is a hybrid vehicle equipped with an engine 12 and an electric motor MG, which are driving power sources for traveling. The vehicle 10 also has driving wheels 14 and a power transmission device 16 provided in a power transmission path between the engine 12 and the driving wheels 14.

[0021] The engine 12 is a known internal combustion engine such as a gasoline engine, a diesel engine, etc. An engine control device 50 including a throttle actuator, a fuel injection device, an ignition device, etc., provided in the vehicle 10 is controlled by an electronic control device 90 described later, whereby an engine torque Te, which is an output torque of the engine 12, is controlled.

[0022] The electric motor MG is a rotating electric machine having a function as a motor that generates mechanical power from electric power and a function as a generator that generates electric power from mechanical power, and is a so-called motor generator. The electric motor MG is a driving force source, and is, for example, a generator that generates electric power by the power of the engine 12. The electric motor MG is connected to a battery 54 provided in the vehicle 10 via an inverter 52 provided in the vehicle 10. The battery 54 is an electric storage device that supplies and receives electric power to the electric motor MG. The electric motor MG controls the MG torque Tm, which is the output torque of the electric motor MG, by controlling the inverter 52 by an electronic control device 90 described later. For example, when the rotation direction of the electric motor MG is a positive rotation, which is the same as the rotation direction when the engine 12 is in operation, the MG torque Tm is a power torque when it is a positive torque on the acceleration side, and is a regenerative torque when it is a negative torque on the deceleration side. The electric power also means electric energy when there is no particular distinction. The power also means torque and force when there is no particular distinction.

[0023] The power transmission device 16 includes a K0 clutch 20, a torque converter 22, an automatic transmission 24, and the like, in a case 18 that is a non-rotating member attached to the vehicle body. The K0 clutch 20 is a clutch provided between the engine 12 and the electric motor MG in a power transmission path between the engine 12 and the drive wheels 14. The torque converter 22 is connected to the engine 12 via the K0 clutch 20. The automatic transmission 24 is connected to the torque converter 22, and is interposed in the power transmission path between the torque converter 22 and the drive wheels 14. The power transmission device 16 also includes a propeller shaft 28 connected to a transmission output shaft 26 that is an output rotating member of the automatic transmission 24, a differential gear 30 connected to the propeller shaft 28, a pair of drive shafts 32 connected to the differential gear 30, and the like. The power transmission device 16 also includes an engine connecting shaft 34 that connects the engine 12 and the K0 clutch 20, an electric motor connecting shaft 36 that connects the K0 clutch 20 and the torque converter 22, and the like.

[0024] The electric motor MG is connected to the electric motor connecting shaft 36 in the case 18 so as to be capable of transmitting power. In other words, the electric motor MG is connected to a power transmission path between the K0 clutch 20 and the torque converter 22 so as to be capable of transmitting power. In other words, the electric motor MG is connected to the torque converter 22 and the automatic transmission 24 so as to be capable of transmitting power without passing through the K0 clutch 20.

[0025] The torque converter 22 includes a pump wheel 22a connected to the motor connecting shaft 36, and a turbine wheel 22b connected to a transmission input shaft 38 that is an input rotating member of the automatic transmission 24. The torque converter 22 is a fluid type power transmission device that transmits driving force from each of the driving force sources (engine 12, electric motor MG) from the motor connecting shaft 36 to the transmission input shaft 38 via fluid. The torque converter 22 includes an LU clutch 40 as a direct clutch that connects the pump wheel 22a and the turbine wheel 22b, that is, that connects the motor connecting shaft 36 and the transmission input shaft 38. The LU clutch 40 is a known lock-up clutch.

[0026] The automatic transmission 24 is a known planetary gear type automatic transmission including, for example, one or more planetary gear devices (not shown) and a plurality of engagement devices CB. The engagement devices CB are, for example, known hydraulic friction engagement devices. The engagement devices CB have their respective torque capacities, or CB torque Tcb, changed by the CB hydraulic pressure PRcb, or regulated hydraulic pressure, supplied from the hydraulic control circuit 56, thereby switching between operating states, such as an engaged state and a released state, i.e., control states.

[0027] The automatic transmission 24 is a stepped transmission in which one of a plurality of gear stages (also called gear stages) with different speed ratios (also called gear ratios) γat (=AT input rotation speed Ni / AT output rotation speed No) is formed by engaging one of the engagement devices CB. The automatic transmission 24 switches between gear stages formed according to the accelerator operation of the driver (=operator) and the vehicle speed V by an electronic control device 90 described later. The AT input rotation speed Ni is the rotation speed of the transmission input shaft 38, and is the input rotation speed of the automatic transmission 24. The AT input rotation speed Ni is the same value as the turbine rotation speed Nt, which is the output rotation speed of the torque converter 22. The AT input rotation speed Ni can be expressed by the turbine rotation speed Nt. The AT output rotation speed No is the rotation speed of the transmission output shaft 26, and is the output rotation speed of the automatic transmission 24.

[0028] The K0 clutch 20 is a hydraulic friction engagement device constituted by, for example, a multi-plate or single-plate clutch. The K0 clutch 20 switches between control states such as an engaged state and a released state by changing the torque capacity of the K0 clutch 20, that is, the K0 torque Tk0, by the K0 oil pressure PRk0, that is, the regulated oil pressure supplied from the hydraulic control circuit 56.

[0029] In the vehicle 10, when the K0 clutch 20 is in an engaged state, the engine 12 and the torque converter 22 are connected to each other so as to transmit power. On the other hand, when the K0 clutch 20 is in a disengaged state, power transmission between the engine 12 and the torque converter 22 is interrupted. Since the electric motor MG is connected to the torque converter 22, the K0 clutch 20 functions as a clutch that connects and disconnects the engine 12 from the electric motor MG.

[0030] In the power transmission device 16, when the K0 clutch 20 is engaged, the power output from the engine 12 is transmitted from the engine connecting shaft 34 to the driving wheels 14 via the K0 clutch 20, the electric motor connecting shaft 36, the torque converter 22, the automatic transmission 24, the propeller shaft 28, the differential gear 30, the drive shaft 32, etc. in this order. Moreover, the power output from the electric motor MG is transmitted from the electric motor connecting shaft 36 to the driving wheels 14 via the torque converter 22, the automatic transmission 24, the propeller shaft 28, the differential gear 30, the drive shaft 32, etc. in this order, regardless of the control state of the K0 clutch 20.

[0031] The vehicle 10 includes the MOP 58, which is a mechanical oil pump, the EOP 60, which is an electric oil pump, and a pump motor 62. The MOP 58 is connected to the pump impeller 22a, and is rotated and driven by a driving force source (the engine 12, the electric motor MG) to discharge hydraulic oil OIL used in the power transmission device 16. The pump motor 62 is a motor dedicated to the EOP 60 for rotating and driving the EOP 60. The EOP 60 is rotated and driven by the pump motor 62 to discharge hydraulic oil OIL. The hydraulic oil OIL discharged by the MOP 58 and the EOP 60 is supplied to a hydraulic control circuit 56. The hydraulic control circuit 56 supplies the CB hydraulic pressure PRcb, the K0 hydraulic pressure PRk0, and the like, which are adjusted based on the hydraulic oil OIL discharged by the MOP 58 and / or the EOP 60.

[0032] The vehicle 10 further includes an electronic control device 90 including a control device for the vehicle 10. The electronic control device 90 includes a so-called microcomputer equipped with, for example, a CPU, RAM, ROM, an input / output interface, and the like, and the CPU executes various controls of the vehicle 10 by performing signal processing according to a program previously stored in the ROM while utilizing the temporary storage function of the RAM. The electronic control device 90 includes computers for engine control, electric motor control, hydraulic control, and the like as necessary.

[0033] The electronic control device 90 is supplied with various signals based on detection values ​​by various sensors provided in the vehicle 10 (e.g., engine rotation speed sensor 70, turbine rotation speed sensor 72, output rotation speed sensor 74, MG rotation speed sensor 76, accelerator opening sensor 78, throttle valve opening sensor 80, brake switch 82, battery sensor 84, oil temperature sensor 86, etc.) (e.g., engine rotation speed Ne, which is the rotation speed of the engine 12, turbine rotation speed Nt, which is the same value as the AT input rotation speed Ni, AT output rotation speed No corresponding to the vehicle speed V, MG rotation speed Nm, which is the rotation speed of the electric motor MG, accelerator opening θacc, which is the amount of accelerator operation by the driver indicating the magnitude of the driver's acceleration operation, throttle valve opening θth, which is the opening of the electronic throttle valve, brake-on signal Bon, which is a signal indicating a state in which the brake pedal for operating the wheel brakes is being operated by the driver, battery temperature THbat, battery charge / discharge current Ibat, and battery voltage Vbat of the battery 54, and hydraulic oil temperature THoil, which is the temperature of the hydraulic oil OIL in the hydraulic control circuit 56).

[0034] The electronic control device 90 outputs various command signals (e.g., an engine control command signal Se for controlling the engine 12, an MG control command signal Sm for controlling the electric motor MG, a CB hydraulic control command signal Sbc for controlling the engagement device CB, a K0 hydraulic control command signal Sk0 for controlling the K0 clutch 20, an LU hydraulic control command signal Slu for controlling the LU clutch 40, an EOP control command signal Seop for controlling the EOP 60, etc.) to each device (e.g., the engine control device 50, the inverter 52, the hydraulic control circuit 56, the pump motor 62, etc.) provided in the vehicle 10.

[0035] The electronic control unit 90 includes a hybrid control means, i.e., a hybrid control unit 92, and a gear shift control means, i.e., a gear shift control unit 94 in order to realize various controls in the vehicle 10.

[0036] The hybrid control unit 92 includes a function as an engine control means, i.e., an engine control unit 92a, that controls the operation of the engine 12, and a function as an electric motor control means, i.e., an electric motor control unit 92b, that controls the operation of the electric motor MG via the inverter 52, and performs hybrid drive control using the engine 12 and the electric motor MG, etc., using these control functions.

[0037] The hybrid control unit 92 calculates the driving demand amount of the vehicle 10 by the driver, for example, by applying the accelerator opening θacc and the vehicle speed V to a driving demand amount map. The driving demand amount map is a relationship that is experimentally or design-wise determined and stored in advance, that is, a predetermined relationship. The driving demand amount is, for example, a required driving torque Trdem at the driving wheels 14. In other words, the required driving torque Trdem [Nm] is the required driving power Prdem [W] at the vehicle speed V at that time. The driving demand amount can also be the required driving force Frdem [N] at the driving wheels 14, the required AT output torque at the transmission output shaft 26, or the like. In calculating the driving demand amount, the AT output rotation speed No, or the like, can be used instead of the vehicle speed V.

[0038] The hybrid control unit 92 outputs an engine control command signal Se for controlling the engine 12 and an MG control command signal Sm for controlling the electric motor MG so as to realize the required driving power Prdem, taking into consideration the transmission loss, the auxiliary load, the gear ratio γat of the automatic transmission 24, the chargeable power Win and the dischargeable power Wout of the battery 54, etc. The engine control command signal Se is, for example, a command value for the engine power Pe, which is the power of the engine 12 that outputs the engine torque Te at the engine rotation speed Ne at that time. The MG control command signal Sm is, for example, a command value for the power consumption Wm of the electric motor MG that outputs the MG torque Tm at the MG rotation speed Nm at that time.

[0039] The chargeable power Win of the battery 54 is the maximum power that can be input, which specifies the limit on the input power of the battery 54, and indicates the input limit of the battery 54. The dischargeable power Wout of the battery 54 is the maximum power that can be output, which specifies the limit on the output power of the battery 54, and indicates the output limit of the battery 54. The chargeable power Win and dischargeable power Wout of the battery 54 are calculated by the electronic control device 90, for example, based on the battery temperature THbat and the battery charge amount SOC. The battery charge amount SOC is a charge state value [%] of the battery 54 that indicates the charge state corresponding to the charge amount of the battery 54, and is calculated by the electronic control device 90, for example, based on the battery charge / discharge current Ibat and the battery voltage Vbat.

[0040] When the required drive torque Trdem can be satisfied only by the output of the electric motor MG, the hybrid control unit 92 sets the drive mode to the motor drive (=EV drive) mode. In the EV drive mode, the hybrid control unit 92 performs EV drive by outputting drive force only from the electric motor MG among the drive power sources (engine 12, electric motor MG) when the K0 clutch 20 is in the released state. On the other hand, when the required drive torque Trdem cannot be satisfied without using at least the output of the engine 12, the hybrid control unit 92 sets the drive mode to the engine drive mode, i.e., hybrid drive (=HV drive) mode. In the HV drive mode, the hybrid control unit 92 performs engine drive by outputting drive force only from the engine 12 among the drive power sources (engine 12, electric motor MG) when the K0 clutch 20 is in the engaged state, i.e., HV drive. On the other hand, even when the required drive torque Trdem can be satisfied only by the output of the electric motor MG, the hybrid control unit 92 establishes the HV drive mode when the battery charge amount SOC is less than the engine start threshold SOCest or when the engine 12 or the like needs to be warmed up. The engine start threshold SOCest is a predetermined threshold for determining that the battery charge SOC is at a level at which the engine 12 needs to be forcibly started to charge the battery 54.

[0041] In the HV driving mode, when the required drive torque Trdem cannot be satisfied by the drive force from the engine 12 alone, the hybrid control unit 92 performs MG assist control CTmas, which is an assist control by the electric motor MG, in which drive force is output from the electric motor MG in addition to the drive force from the engine 12. Specifically, the hybrid control unit 92 determines whether or not there is an acceleration request from the driver. The hybrid control unit 92 determines whether or not there is an acceleration request from the driver based on a change in the accelerator opening degree θacc, for example, from accelerator off to accelerator on, or further depression of the accelerator pedal. When the hybrid control unit 92 determines that there is an acceleration request from the driver, the electric motor control unit 92b performs MG assist control CTmas, which applies drive force from the electric motor MG to the drive wheels 14 in addition to drive force from the engine 12 so as to realize the required drive torque Trdem.

[0042] The shift control unit 94 judges whether or not to shift the automatic transmission 24 by using, for example, a shift map which is a predetermined relationship, and outputs a CB hydraulic control command signal Sbc to the hydraulic control circuit 56 as necessary to execute shift control of the automatic transmission 24. The shift map is a predetermined relationship having a shift line for judging whether or not to shift the automatic transmission 24 on a two-dimensional coordinate system having, for example, vehicle speed V and required driving torque Trdem as variables. In the shift map, the AT output rotation speed No or the like may be used instead of the vehicle speed V, and the required driving force Frdem, accelerator opening θacc, throttle valve opening θth or the like may be used instead of the required driving torque Trdem.

[0043] FIG. 2 is a diagram for explaining the MG assist control CTmas. In FIG. 2, for example, in the HV driving mode, the presence or absence of an acceleration request by the driver is determined based on the accelerator opening θacc (see [1] in the figure). When it is determined that there is an acceleration request by the driver, the MG assist control CTmas is executed as necessary. Time t1 indicates the time when the MG assist control CTmas is started. In the MG assist control CTmas, for example, a shortage torque Tsa (=Tspt-Te) (see dashed line C), which is a shortage torque of the engine torque Te with respect to the target torque Tspt, which is the difference between the target torque Tspt (see dashed line A) by the driver's operation and the engine torque Te (see solid line B), is output as the MG torque Tm (see solid line D) (see [2] in the figure). The target torque Tspt by the driver's operation is a target value of the torque that needs to be output from the driving force source (engine 12, electric motor MG) to realize the required driving torque Trdem. By executing the MG assist control CTmas, the target torque Tspt operated by the driver is more easily achieved, and the acceleration feeling can be improved.

[0044] In Fig. 2, as described later, the end of the MG assist control CTmas is determined at time t2, but the MG assist control CTmas may be continued after time t2 without determining the end of the MG assist control CTmas. In this case, the shortage torque Tsa is output as the MG torque Tm after time t2, and the target torque Tspt is output as the actual realized torque (=Te+Tm) (see thick solid line E), which is the total torque of the actual value of the engine torque Te and the actual value of the MG torque Tm, after time t2. In other words, the electric motor control unit 92b performs the MG assist control CTmas by compensating for the shortage of the driving force by the engine 12 when realizing the required driving torque Trdem with the driving force by the electric motor MG.

[0045] In FIG. 2, the end of the MG assist control CTmas is determined at time t2. For example, when the MG assist time consumed energy EGm, which is the energy consumed by the electric motor MG in the MG assist control CTmas, exceeds a predetermined energy EGmf (see [3] in the figure), the end of the MG assist control CTmas is determined. The MG assist time consumed energy EGm is, for example, a time integral value of the electric power discharged from the battery 54 to the electric motor MG in the MG assist control CTmas. The MG assist time consumed energy EGm is a value that is highly related to a decrease in the battery charge amount SOC and / or the amount of heat generated by the battery 54. Therefore, by ending the MG assist control CTmas when the MG assist time consumed energy EGm exceeds the predetermined energy EGmf, it is possible to prevent the MG assist control CTmas from being continued until it becomes difficult to execute the subsequent MG assist control CTmas due to a decrease in the battery charge amount SOC or heat generation by the battery 54 caused by the MG assist control CTmas, which would result in a worsening of the acceleration feeling. That is, the motor control unit 92b calculates the MG assist-time consumed energy EGm based on the discharged power of the battery 54 every time the MG assist control CTmas is performed, determines whether the MG assist-time consumed energy EGm exceeds a predetermined energy EGmf, and terminates the MG assist control CTmas if it is determined that the MG assist-time consumed energy EGm exceeds the predetermined energy EGmf. The MG torque Tm may be set to zero and the MG assist control CTmas may be terminated immediately upon determining that the MG assist-time consumed energy EGm exceeds the predetermined energy EGmf, or the MG torque Tm may be gradually reduced and the MG assist control CTmas terminated as shown in FIG. 2 (times t2-t3, see [4] in the figure). The predetermined energy EGmf is, for example, a predetermined threshold value for suppressing a decrease in the battery charge SOC or heat generation of the battery 54.In this control, the MG torque Tm in the MG assist control CTmas is not limited to the torque deficiency Tsa until the energy consumed during MG assist EGm exceeds a predetermined energy EGmf. In other words, no limitation is imposed in the MG assist control CTmas immediately after the start of acceleration. Therefore, the MG assist control CTmas can be made to work effectively during the period when the rise of the engine torque Te is slow immediately after the accelerator operation, i.e., immediately after the acceleration operation.

[0046] Alternatively, as shown in FIG. 2, instead of judging the end of the MG assist control CTmas when the MG assist consumption energy EGm exceeds a predetermined energy EGmf, the end of the MG assist control CTmas may be judged when the MG assist duration TMmas, which is the duration from the start of the MG assist control CTmas, exceeds a predetermined time TMf (see [5] in the figure). That is, the motor control unit 92b measures the MG assist duration TMmas every time the MG assist control CTmas is performed, judges whether the MG assist duration TMmas exceeds the predetermined time TMf, and terminates the MG assist control CTmas when it is judged that the MG assist duration TMmas exceeds the predetermined time TMf. The predetermined time TMf is, for example, a predetermined threshold value for suppressing a decrease in the battery charge state SOC or heat generation of the battery 54. By using the MG assist duration TMmas, a similar effect can be obtained more simply than by using the MG assist consumption energy EGm. In FIG. 2, for convenience, the time when the MG assist consumption energy EGm exceeds the predetermined energy EGmf and the time when the MG assist duration TMmas exceeds the predetermined time TMf are both set to the same time t2, but the two may be different times.

[0047] By the way, the battery charge amount SOC is reduced by implementing the MG assist control CTmas. At this time, if the battery 54 cannot be charged or is difficult to charge, the battery charge amount SOC remains reduced, making it difficult to implement the subsequent MG assist control CTmas, which may cause a problem in vehicle running. A state in which the battery 54 cannot be charged or is difficult to charge, or in which the charging of the battery 54 is restricted, is, for example, a state in which the output of the engine 12 is restricted and the battery 54 cannot be charged by the electric motor MG using the surplus torque of the engine 12 or is difficult to charge. A state in which the output of the engine 12 is restricted is a state in which the torque output capacity of the engine 12 is reduced.

[0048] Therefore, when the engine 12 is in an output-limited state, the electric motor control unit 92b limits the driving force by the electric motor MG in the MG assist control CTmas regardless of the battery charge amount SOC. When the engine 12 is in an output-limited state, the electric power consumption in the MG assist control CTmas is reduced and the decrease in the battery charge amount SOC is suppressed, so that it is possible to avoid or suppress an event in which the battery charge amount SOC remains in a reduced state and it becomes difficult to execute the subsequent MG assist control CTmas.

[0049] Specifically, when it is determined that there is an acceleration request from the driver, the hybrid control unit 92 determines whether or not the output of the engine 12 is limited. The hybrid control unit 92 determines whether or not the output of the engine 12 is limited based on whether or not there is a malfunction of engine parts such as a throttle actuator, a fuel injection device, or an ignition device provided in the engine control device 50, or a reduction in output due to a difference in fuel.

[0050] When the hybrid control unit 92 determines that the engine 12 is not in an output-limited state, the electric motor control unit 92b permits the normal MG assist control CTmas and implements the normal MG assist control CTmas as necessary. On the other hand, when the hybrid control unit 92 determines that the engine 12 is in an output-limited state, the electric motor control unit 92b limits the normal MG assist control CTmas and implements the limited MG assist control CTmas as necessary. Limiting the normal MG assist control CTmas means, for example, prohibiting the normal MG assist control CTmas or suppressing the normal MG assist control CTmas.

[0051] The normal MG assist control CTmas is, for example, an MG assist control CTmas that uses the driving force of the electric motor MG to make up for the shortage of the driving force of the engine 12 when realizing the required driving torque Trdem. Specifically, the normal MG assist control CTmas is an MG assist control CTmas that outputs the shortage torque Tsa as the MG torque Tm, that is, an MG assist control CTmas in which the assist amount by the electric motor MG is the shortage torque Tsa. Prohibiting the normal MG assist control CTmas means making the assist amount by the electric motor MG in the MG assist control CTmas zero. Suppressing the normal MG assist control CTmas means making the assist amount by the electric motor MG a suppression amount that is smaller than the shortage of the driving force by the engine 12. The suppression amount is, for example, a suppression torque Tsar that is smaller than the shortage torque Tsa. The suppression torque Tsar is, for example, a torque value obtained by multiplying the shortage torque Tsa by a predetermined constant rate (<1). In other words, the electric motor control unit 92b limits the driving force of the electric motor MG in the MG assist control CTmas by setting the driving force of the electric motor MG, which compensates for the shortage of the driving force from the engine 12 when realizing the required driving torque Trdem, to zero or by suppressing it compared to when the engine 12 is in a state where the output is not limited.

[0052] Alternatively, the normal MG assist control CTmas is, for example, an MG assist control CTmas in which a predetermined energy EGmf used for comparison with the MG assist energy consumption EGm when determining the end of the MG assist control CTmas is set to normal energy EGmfu. The normal energy EGmfu is, for example, a predetermined upper limit value for suppressing a decrease in the battery charge state SOC or heat generation of the battery 54. Prohibiting the normal MG assist control CTmas means setting the predetermined energy EGmf to zero. Suppressing the normal MG assist control CTmas means setting the predetermined energy EGmf to suppressed energy EGmfr that is smaller than the normal energy EGmfu. In other words, the electric motor control unit 92b limits the driving force by the electric motor MG in the MG assist control CTmas by setting the predetermined energy EGmf to zero or smaller than when the engine 12 is in a state in which the output is not limited.

[0053] Alternatively, the normal MG assist control CTmas is, for example, an MG assist control CTmas in which a predetermined time TMf used for comparison with the MG assist duration TMmas when determining the end of the MG assist control CTmas is set to a normal time TMfu. The normal time TMfu is, for example, a predetermined upper limit value for suppressing a decrease in the battery charge state SOC or heat generation of the battery 54. Prohibiting the normal MG assist control CTmas means setting the predetermined time TMf to zero. Suppressing the normal MG assist control CTmas means setting the predetermined time TMf to a suppression time TMfr that is shorter than the normal time TMfu. In other words, the electric motor control unit 92b limits the driving force by the electric motor MG in the MG assist control CTmas by setting the predetermined time TMf to zero or making it shorter than when the engine 12 is in a state in which the output is not limited.

[0054] When the driver has a strong intention to accelerate, it is considered that the driver attaches more importance to the acceleration feeling. In addition, when the output responsiveness of the engine 12 is low in response to an acceleration request, the difference between the target torque Tspt and the engine torque Te, i.e., the torque deficiency Tsa, tends to be large, so that a larger driving force by the electric motor MG, i.e., the MG-assisted consumption energy EGm, is required to improve the acceleration feeling. Therefore, the electric motor control unit 92b may change the predetermined energy EGmf or the predetermined time TMf based on at least one of the state of the driver's intention to accelerate and the state of the output responsiveness of the engine 12.

[0055] Specifically, the motor control unit 92b sets the predetermined energy EGmf to be larger when the driver's intention to accelerate is high than when it is low, and sets the predetermined energy EGmf to be larger when the output responsiveness of the engine 12 is low than when it is high. Alternatively, the motor control unit 92b sets the predetermined time TMf to be longer when the driver's intention to accelerate is high than when it is low, and sets the predetermined time TMf to be longer when the output responsiveness of the engine 12 is low than when it is high.

[0056] The state of the driver's intention to accelerate is indicated, for example, by the state of accelerator operation, the state of a shift lever operation provided in the vehicle 10, the state of a driving mode switch, etc. The motor control unit 92b determines that the driver has a strong intention to accelerate when the accelerator opening θacc is larger than a predetermined opening, when the rate of change of the accelerator opening θacc is larger than a predetermined rate of change, when the shift lever is operated to select a gear position on the lower vehicle speed side of the automatic transmission 24, or when the driver has selected a driving mode that prioritizes driving performance, such as a sports driving mode, with the driving mode switch.

[0057] The state of the output responsiveness of the engine 12 is represented by, for example, the engine rotation speed Ne, the gear of the automatic transmission 24, and if the engine 12 is a supercharged engine, the supercharging pressure of the supercharger. The electric motor control unit 92b determines that the output responsiveness of the engine 12 is low when the engine rotation speed Ne is lower than a predetermined rotation speed, when the gear of the automatic transmission 24 is a gear on the higher vehicle speed side than the predetermined gear, or when the supercharging pressure is lower than the predetermined supercharging pressure.

[0058] FIG. 3 is a flowchart illustrating the main control operations of the electronic control device 90, which are executed, for example, repeatedly, to suppress interference with vehicle driving when charging of the battery 54 is restricted.

[0059] In FIG. 3, first, in step S10 (hereinafter, step will be omitted) corresponding to the function of the hybrid control unit 92, it is determined whether or not there is an acceleration request by the driver. If the determination in S10 is negative, this routine is terminated. If the determination in S10 is positive, it is determined in S20 corresponding to the function of the hybrid control unit 92 whether or not the engine 12 is in an output-limited state. If the determination in S20 is negative, in S30 corresponding to the function of the electric motor control unit 92b, the normal MG assist control CTmas is permitted, and the normal MG assist control CTmas is performed as necessary. If the determination in S20 is positive, in S40 corresponding to the function of the electric motor control unit 92b, the normal MG assist control CTmas is limited, and the limited MG assist control CTmas is performed as necessary.

[0060] As described above, according to this embodiment, when the engine 12 is in an output-limited state, the driving force by the electric motor MG in the MG assist control CTmas is limited regardless of the battery charge SOC, so that while the charging of the battery 54 by the electric motor MG is limited due to the output of the engine 12 being limited, the power consumption by the electric motor MG is suppressed due to the limitation in the MG assist control CTmas, and the decrease in the battery charge SOC is suppressed, making it easier to execute the subsequent MG assist control CTmas. Therefore, it is possible to suppress interference with vehicle travel when the battery charge SOC is limited.

[0061] Furthermore, according to this embodiment, the driving force of the electric motor MG that compensates for the insufficiency of the driving force from the engine 12 in the MG assist control CTmas is set to zero or is suppressed compared to when the engine 12 is in a state where the output of the engine 12 is not limited, so that the driving force of the electric motor MG in the MG assist control CTmas is limited, and therefore the power consumption by the electric motor MG is appropriately suppressed and the decrease in the battery charge state SOC is appropriately suppressed.

[0062] Furthermore, according to this embodiment, each time the MG assist control CTmas is performed, the MG assist control CTmas is terminated when the energy consumed during MG assist EGm exceeds a predetermined energy EGmf, or the assist control is terminated when the MG assist duration TMmas exceeds a predetermined time TMf, so it is possible to prevent a decrease in the battery charge SOC due to the performance of the MG assist control CTmas or heat generation by the battery 54 making it difficult to perform the subsequent MG assist control CTmas.

[0063] Furthermore, according to this embodiment, the predetermined energy EGmf is set to zero or made smaller than when the engine 12 is in a state where the output is not limited, or the predetermined time TMf is set to zero or made shorter than when the engine 12 is in a state where the output is not limited, thereby limiting the driving force by the electric motor MG in the MG assist control CTmas, thereby appropriately suppressing the power consumption by the electric motor MG and appropriately suppressing the decrease in the battery charge state SOC.

[0064] According to this embodiment, the predetermined energy EGmf is set larger when the driver's intention to accelerate is high than when it is low, and larger when the output responsiveness of the engine 12 is low than when it is high, or the predetermined time TMf is set longer when the driver's intention to accelerate is high than when it is low, and longer when the output responsiveness of the engine 12 is low than when it is high, so that when the driver's intention to accelerate is high or the output responsiveness of the engine 12 is low, the implementation time of the MG assist control CTmas is relatively long, which makes it easier to improve the driving feeling. When the driver's intention to accelerate is low or the output responsiveness of the engine 12 is high, the implementation time of the MG assist control CTmas is relatively short, which makes it easier to suppress energy consumption.

[0065] Although the embodiment of the present invention has been described in detail above with reference to the drawings, the present invention can be applied to other embodiments.

[0066] For example, in the above embodiment, a planetary gear type automatic transmission is exemplified as the automatic transmission 24, but the present invention is not limited to this. The automatic transmission 24 may be a synchronous mesh type parallel two-shaft automatic transmission including a known DCT (Dual Clutch Transmission), a known belt type continuously variable transmission, or the like. Alternatively, the automatic transmission 24 does not necessarily have to be provided. In short, the present invention can be applied to any vehicle that includes an engine as a driving force source, an electric motor as a generator that generates electricity using the power of the engine as the driving force source, and an electricity storage device that supplies and receives electricity to and from the electric motor.

[0067] In the above embodiment, the torque converter 22 is used as the fluid transmission device, but the present invention is not limited to this. For example, instead of the torque converter 22, another fluid transmission device that does not amplify torque, such as a fluid coupling, may be used as the fluid transmission device. Alternatively, the fluid transmission device does not necessarily have to be provided, and may be replaced with, for example, a starting clutch.

[0068] It should be noted that the above is merely one embodiment, and the present invention can be embodied in various modified and improved forms based on the knowledge of those skilled in the art. [Explanation of symbols]

[0069] 10: Vehicle 12: Engine 14: Drive wheel 54: Battery (energy storage device) 90: Electronic control device (control device) 92b: Motor control unit MG: Electric motor

Claims

1. A control device for a vehicle including an engine as a driving force source, an electric motor as the driving force source and a generator that generates electricity by the power of the engine, and an electric storage device that supplies and receives electric power to the electric motor, an electric motor control unit that performs an assist control by the electric motor to apply a driving force by the electric motor to a driving wheel in addition to a driving force by the engine so as to realize a driving demand amount for the vehicle when there is an acceleration demand by a driver, the electric motor control unit limits a driving force by the electric motor in the assist control when the engine is in an output-limited state, regardless of a charge amount of the power storage device, the electric motor control unit terminates the assist control when the energy consumed by the electric motor in the assist control exceeds a predetermined energy for suppressing a decrease in a charge amount of the power storage device or heat generation of the power storage device, each time the assist control is performed; the electric motor control unit limits the driving force of the electric motor in the assist control by setting the predetermined energy to zero or to a value smaller than that in a state in which the engine is not output-limited, the electric motor control unit changes the predetermined energy based on at least one of a state of an intention of the driver to accelerate and a state of an output responsiveness of the engine, A vehicle control device characterized in that the motor control unit sets the specified energy to be larger when the driver's intention to accelerate is high compared to when it is low, and sets the specified energy to be larger when the output responsiveness of the engine is low compared to when it is high.

2. A control device for a vehicle including an engine as a driving force source, an electric motor as the driving force source and a generator that generates electricity using the power of the engine, and an electric storage device that supplies and receives electric power to the electric motor, an electric motor control unit that performs an assist control by the electric motor to apply a driving force by the electric motor to a driving wheel in addition to a driving force by the engine so as to realize a driving demand amount for the vehicle when there is an acceleration demand by a driver, the electric motor control unit limits a driving force by the electric motor in the assist control when the engine is in an output-limited state, regardless of a charge amount of the power storage device, the electric motor control unit terminates the assist control when a duration from a start point of the assist control exceeds a predetermined time for suppressing a decrease in a charge amount of the power storage device or heat generation of the power storage device, each time the assist control is performed, A vehicle control device characterized in that the motor control unit limits the driving force of the electric motor in the assist control by setting the specified time to zero or making it shorter than when the engine is in a state where its output is not restricted.

3. the motor control unit changes the predetermined time based on at least one of a state of an intention of the driver to accelerate and a state of an output responsiveness of the engine, The vehicle control device according to claim 2, characterized in that the motor control unit makes the predetermined time longer when the driver's intention to accelerate is high compared to when it is low, and makes the predetermined time longer when the output responsiveness of the engine is low compared to when it is high.

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