Vehicle control device

Abstract

To provide a control device of a vehicle that can suppress responsiveness of the vehicle to torque required by a driver from deteriorating just after an EV mode is switched to an HEV mode.SOLUTION: An ECU, when predetermined operation in which it is assumed that motor torque cannot satisfy torque required by a driver fully, which is accompanied by at least either of shift operation and clutch operation to a clutch pedal, even during EV mode (time t23), starts to activate an engine. The predetermined operation is the shift operation by which a gear shift stage is down-shifted to a gear shift stage closer by two stages or more to a lower speed side. The ECU, even when the predetermined operation is performed during the EV mode, does not start to activate the engine, when brake operation to a brake pedal is performed.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a vehicle control device. [Background technology]

[0002] In recent years, due to social demands for low fuel consumption and low exhaust emissions, hybrid vehicles equipped with an engine and a motor as a power source for the vehicle have been attracting attention. Patent Document 1 discloses a drive control device for a hybrid vehicle that switches between an EV mode in which the clutch is released and the vehicle runs on power from the motor, and an HV mode in which the clutch is engaged and the vehicle runs on power from at least the engine or the motor. In such vehicles, it is desirable to be able to transition from the EV mode to the HV mode without causing any discomfort to the driver.

[0003] The system described in Patent Document 1 does not engage the clutch immediately after the engine starts, but instead fully engages the clutch after the rotational speed of the motor generator approaches the engine's ideal fuel-efficient rotational speed. This prevents the engine from revving up while preventing the engine's rotational speed from remaining high, and allows the rotational speeds of the engine and motor generator to be smoothly controlled to the engine's ideal fuel-efficient rotational speed without causing any discomfort to the driver. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6070577 Summary of the Invention [Problem to be solved by the invention]

[0005] In a hybrid vehicle, the motor generator and the engine are controlled so that the driver's requested torque is satisfied by the motor torque and the engine torque. The hybrid vehicle described in Patent Document 1 switches to HEV mode (HV mode) when the motor torque is no longer sufficient to satisfy the driver's requested torque in EV mode, in which the vehicle runs on the motor torque. Therefore, it is desirable to make it possible to compensate for the shortage of motor torque relative to the driver's requested torque with engine torque immediately after switching to HEV mode. If the engine torque is insufficient immediately after switching to HEV mode, the vehicle's torque will be insufficient relative to the driver's requested torque, and the vehicle's responsiveness to the driver's requested torque will deteriorate.

[0006] However, the technology described in Patent Document 1 does not consider suppressing deterioration in vehicle responsiveness due to insufficient engine torque immediately after switching to HEV mode.

[0007] Therefore, an object of the present invention is to provide a vehicle control device that can suppress deterioration in the vehicle's responsiveness to the driver's requested torque immediately after switching from EV mode to HEV mode. [Means for solving the problem]

[0008] In order to solve the above problems, the present invention is provided for a vehicle that is equipped with an engine that generates engine torque, a motor that generates motor torque, a manual transmission that is arranged between the engine and the motor and that changes gears by shifting a shift lever, and a clutch that is arranged between the engine and the manual transmission and that is disengaged or engaged by operation of a clutch actuator, and the vehicle is equipped with an EV mode in which the engine is stopped, the clutch is disengaged, and the driver's requested torque is satisfied by the motor torque, and a VE mode in which the engine is operated, the clutch is engaged, and the engine torque and the Motor torque andand an HEV mode in which the vehicle travels while satisfying the driver's requested torque with at least the engine torque, and the vehicle is equipped with a control unit that switches to the HEV mode when the driver's requested torque cannot be satisfied with the motor torque in the EV mode, and the control unit is configured to start the engine when a predetermined operation that involves at least one of the shift operation and the clutch operation on the clutch pedal and that is expected to cause the driver's requested torque to be unable to be satisfied with the motor torque is performed even during the EV mode. The predetermined operation is a shift operation for downshifting to a gear position that is two or more steps lower. It is characterized by: [Effects of the Invention]

[0009] As described above, the present invention can provide a vehicle control device that can suppress deterioration in the vehicle's responsiveness to the driver's requested torque immediately after switching from EV mode to HEV mode. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing the configuration of a vehicle equipped with a vehicle control device according to a first or second embodiment of the present invention. [Figure 2] FIG. 2 is a timing chart showing the transition of the vehicle state when starting the engine in the vehicle control device according to the first embodiment of the present invention. [Figure 3] FIG. 3 is a timing chart showing the transition of the vehicle state when starting the engine in the vehicle control device according to the second embodiment of the present invention. [Figure 4] FIG. 4 is a timing chart showing the transition of the vehicle state when the engine start is not initiated in the vehicle control device according to the second embodiment of the present invention. [Figure 5] FIG. 5 is a diagram showing a method for predicting the accelerator opening in a vehicle control device according to a second embodiment of the present invention. [Figure 6] FIG. 6 is a timing chart showing the transition of the vehicle state of a vehicle control device according to a comparative example. DETAILED DESCRIPTION OF THE INVENTION

[0011] A vehicle control device according to one embodiment of the present invention is mounted on a vehicle that includes an engine that generates engine torque, a motor that generates motor torque, a manual transmission that is arranged between the engine and the motor and changes gears by shifting the shift lever, and a clutch that is arranged between the engine and the manual transmission and is disengaged or engaged by operation of a clutch actuator, and has an EV mode in which the engine is stopped, the clutch is disengaged, and the vehicle runs while satisfying the driver's requested torque with the motor torque, and an HEV mode in which the engine is operated, the clutch is engaged, and the vehicle runs while satisfying the driver's requested torque with at least the engine torque and the engine torque, and is a vehicle control device that includes a control unit that switches to HEV mode when the driver's requested torque can no longer be satisfied with the motor torque in EV mode, and is characterized in that the control unit initiates engine start-up when a predetermined operation is performed, even in EV mode, that involves at least one of a shift operation or a clutch operation on the clutch pedal and that is expected to result in the driver's requested torque being unable to be satisfied with the motor torque.

[0012] As a result, the control device for a vehicle according to one embodiment of the present invention can suppress deterioration in the responsiveness of the vehicle to the driver requested torque immediately after switching from the EV mode to the HEV mode. [Example]

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle equipped with a control device according to an embodiment of the present invention will be described in detail below with reference to the drawings. Note that the rotational speed used in the following description indicates the rotational speed (rpm).

[0014] In FIG. 1, a vehicle 1 according to one embodiment of the present invention is configured to include an engine 2, a motor generator 3 for driving as a motor, a manual transmission 4, a differential 5, drive wheels 6, and an ECU (Electronic Control Unit) 10 as a control unit.

[0015] The engine 2 has a plurality of cylinders. In this embodiment, the engine 2 is configured to perform a series of four strokes for each cylinder, including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke. The engine 2 generates engine torque.

[0016] An ISG (Integrated Starter Generator) 20 is connected to the engine 2. The ISG 20 is connected to the crankshaft of the engine 2 via a belt 21 or the like. The ISG 20 functions as an electric motor that rotates when supplied with electric power to drive the engine 2, and also functions as a generator that converts the rotational force input from the crankshaft into electric power.

[0017] The motor generator 3 functions as an electric motor that generates driving force for the vehicle using power supplied from the battery 31 via the inverter 30, and as a generator that performs regenerative power generation using the rotational force (reverse driving force) input from the drive wheels 6 via the differential 5. The motor generator 3 constitutes the motor in the present invention and generates motor torque.

[0018] Under the control of the ECU 10, the inverter 30 converts DC power supplied from the battery 31 into three-phase AC power and supplies it to the motor generator 3, and also converts the three-phase AC power generated by the motor generator 3 into DC power to charge the battery 31. The battery 31 is formed of a secondary battery such as a lithium-ion battery.

[0019] The manual transmission 4 is disposed between the engine 2 and the motor generator 3. The manual transmission 4 is mechanically connected to a shift lever 40. The gear positions of the manual transmission 4 are changed by a shift operation on the shift lever 40.

[0020] The manual transmission 4 changes the speed of the rotation input from the engine 2 to the input shaft 8 via the clutch 7 at a gear ratio corresponding to one of a plurality of gear stages, and outputs the result from the output shaft 9. In this embodiment, the manual transmission 4 is configured as a parallel shaft gear type manual transmission.

[0021] An output shaft 9 of the manual transmission 4 is connected to the motor generator 3. An output shaft 3A of the motor generator 3 is connected to left and right drive wheels 6 via a differential 5. In this way, the vehicle 1 is provided with the motor generator 3 between the manual transmission 4 and the differential 5. The vehicle 1 is configured as a hybrid vehicle that can run using the driving force of at least one of the engine 2 and the motor generator 3.

[0022] The gears that can be established in the manual transmission 4 include, for example, forward gears ranging from a low 1st gear to a high 5th gear, and a reverse gear. The number of driving gears varies depending on the specifications of the vehicle 1, and is not limited to the above-mentioned 1st gear to 5th gear.

[0023] The gears in the manual transmission 4 can be changed according to the operating position of a shift lever 40 operated by the driver. The operating positions of the shift lever 40 include positions corresponding to first to fifth gears, a position corresponding to a reverse gear, and a position corresponding to a neutral state in which no gear is configured, and these positions are arranged to form a so-called H-shaped shift pattern. The gears in the manual transmission 4 are changed when the driver's operation of the shift lever 40 is mechanically transmitted to a transmission mechanism via a transmission mechanism such as a cable.

[0024] The manual transmission 4 is provided with a shift position sensor 41, which detects the gear position (including the neutral position) of the manual transmission 4. The shift position sensor 41 is connected to the ECU 10 and transmits the detection result to the ECU 10.

[0025] In this embodiment, the shift lever 40 is mechanically connected to the manual transmission 4, and no intervention by the ECU 10 occurs, so the operating position of the shift lever 40 matches the gear position of the manual transmission 4. Therefore, a shift position sensor 41 may be provided on the shift lever 40 instead of the manual transmission 4, and the shift position sensor 41 may detect the operating position of the shift lever 40 and send it to the ECU 10.

[0026] A clutch 7 is provided in the power transmission path between the engine 2 and the manual transmission 4. The clutch 7 is a by-wire clutch that is disengaged or engaged by the operation of a clutch actuator 70, which will be described later. The clutch 7 may be, for example, a dry single-plate friction clutch. The engine 2 and the manual transmission 4 are connected via the clutch 7.

[0027] In this way, the manual transmission 4 is configured so that power is transmitted from the engine 2 to the input shaft 8 via the clutch 7, and the gear position can be changed by a shift operation. The clutch 7 is equipped with a clutch disc, and the clutch disc and the input shaft 8 of the manual transmission 4 are interconnected and rotate integrally. Therefore, the rotation speed of the clutch disc is equal to the rotation speed of the input shaft 8 of the manual transmission 4.

[0028] The clutch 7 is operated by a clutch actuator 70 and can be switched between an engaged state in which power is transmitted between the engine 2 and the manual transmission 4, a disengaged state in which power is not transmitted, and a half-clutch state in which torque is transmitted with a rotational difference. The clutch actuator 70 is connected to and controlled by the ECU 10.

[0029] The clutch 7 is provided with a clutch rotation speed sensor 43. The clutch rotation speed sensor 43 detects the rotation speed of the clutch disc of the clutch 7 (hereinafter also referred to as clutch rotation speed). The clutch rotation speed sensor 43 is connected to the ECU 10 and transmits the detection result to the ECU 10.

[0030] The ECU 10 controls the clutch actuator 70 in accordance with the depression amount of the clutch pedal 71 operated by the driver, and controls the clutch 7 so that it operates in the same manner as a manual clutch. The ECU 10 also controls the clutch actuator 70 regardless of the operation of the clutch pedal 71 by the driver, and can change the state of the clutch 7.

[0031] More specifically, in an HEV mode (to be described later), the ECU 10 controls the clutch actuator 70 in accordance with the depression amount of the clutch pedal 71, and in an EV mode (to be described later), the ECU 10 controls the clutch actuator 70 so as to maintain the clutch 7 in an released state regardless of the operation of the clutch pedal 71. In this way, the clutch 7 is released or engaged by driving the clutch actuator 70 in accordance with the clutch operation on the clutch pedal 71 or a control command from the ECU 10. Therefore, the clutch 7 is not mechanically connected to the clutch pedal 71, but is a by-wire clutch that is driven via an electrical signal.

[0032] The depression amount of the clutch pedal 71 is detected by a clutch pedal sensor 72. The clutch pedal sensor 72 is connected to the ECU 10, detects the depression amount of the clutch pedal 71 as a clutch pedal stroke amount, and transmits a signal corresponding to the clutch pedal stroke amount to the ECU 10.

[0033] In this embodiment, the load from the clutch 7 (the restoring force of a diaphragm spring, not shown) does not act on the clutch pedal 71, and therefore the driver cannot feel the operation (response) of the clutch pedal 71. Therefore, the clutch pedal 71 is provided with a pseudo-load device 71A, which applies a pseudo-load to the clutch pedal 71 that simulates the load when the clutch pedal 71 is operated.

[0034] The vehicle 1 is equipped with an accelerator pedal 90 that is operated by the driver. The amount of depression of the accelerator pedal 90 is detected by an accelerator opening sensor 91. The accelerator opening sensor 91 is connected to the ECU 10, detects the amount of depression of the accelerator pedal 90 as an accelerator opening, and transmits a signal corresponding to the accelerator opening to the ECU 10.

[0035] The vehicle 1 is equipped with a brake pedal 92 that is operated by the driver. The amount of depression of the brake pedal 92 is detected by a brake pedal sensor 93. The brake pedal sensor 93 is connected to the ECU 10 and transmits a signal corresponding to the amount of depression of the brake pedal 92 to the ECU 10.

[0036] The ECU 10 is composed of a computer unit having a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), flash memory for storing backup data, etc., input ports, and output ports.

[0037] The ROM of the computer unit stores various constants, various maps, and the like, as well as a program for causing the computer unit to function as the ECU 10. That is, the CPU executes the program stored in the ROM using the RAM as a work area, causing the computer unit to function as the ECU 10 in this embodiment.

[0038] In addition to the above-mentioned sensors, a vehicle speed sensor 11 is connected to the ECU 10. The vehicle speed sensor 11 detects the speed of the vehicle 1 and transmits the detection result to the ECU 10.

[0039] The ECU 10 switches the driving mode of the vehicle 1. The ECU 10 has an EV mode and an HEV mode as driving modes, and switches between the EV mode and the HEV mode.

[0040] The EV mode is a driving mode in which the engine 2 is stopped, the clutch 7 is disengaged, and the motor torque of the motor generator 3 satisfies the driver's requested torque to drive the vehicle 1. In the EV mode, the engine 2 is not operating, so the engine speed is maintained at zero. Also, in the EV mode, the clutch 7 is disengaged, so the engine 2 is prevented from rotating together with the motor generator 3.

[0041] In detail, in the EV mode, regardless of whether the driver operates the clutch pedal 71, the actual clutch position of the clutch 7 (the actual position of the clutch 7) is maintained in the open position, and power transmission between the engine 2 and the manual transmission 4 is cut off.

[0042] The HEV mode is a driving mode in which the engine 2 is operated, the clutch 7 is engaged, and the driver's requested torque is satisfied by at least the engine torque of the engine 2 and the motor torque of the motor generator 3, causing the vehicle 1 to travel. In other words, in the HEV mode, the vehicle travels using only the engine torque, or using both the engine torque and the motor torque.

[0043] When the motor torque is no longer able to satisfy the driver's requested torque while the vehicle is running in the EV mode, the ECU 10 switches from the EV mode to the HEV mode. Specifically, the ECU 10 switches to the HEV mode when the motor outputtable torque, which is the maximum motor torque that can be generated by the motor generator 3 and is determined based on the state of charge of the battery 31, is no longer able to satisfy the driver's requested torque (when the driver's requested torque increases and exceeds the motor outputtable torque).

[0044] When switching from EV mode to HEV mode based on an increase in driver requested torque, immediately after switching to HEV mode, ECU 10 controls motor generator 3 and engine 2 so that the shortage of motor torque relative to driver requested torque is compensated for by engine torque.

[0045] In this embodiment, the torque acting on the output shaft 3A of the motor generator 3 is referred to as the axle torque. In addition, in the vehicle 1 equipped with the manual transmission 4 and the clutch 7, the driver-requested torque is determined based on not only the accelerator opening but also the depression amount of the clutch pedal 71.

[0046] For example, when clutch pedal 71 is not depressed (depression amount is 0%), the magnitude of the accelerator opening degree indicates the magnitude of the driver-requested torque, but when clutch pedal 71 is depressed by 50% (assuming that the engagement degree and transmission torque of clutch 7 are 50%), the driver-requested torque becomes 50% of the value when clutch pedal 71 is not depressed. Therefore, in this specification, the driver-requested torque determined from the accelerator opening degree and the depression amount of clutch pedal 71 is referred to as the post-clutch-limited axle-requested torque.

[0047] If the engine 2 has not yet completed starting (is in the process of starting) immediately after switching to the HEV mode, the engine torque cannot be used as a driving source for driving, and the shortage of motor torque relative to the driver-requested torque cannot be fully compensated for by the engine torque. In this case, the responsiveness of the vehicle 1 to the driver-requested torque may deteriorate. This state is called "hesitation" because the driver feels that the vehicle 1 is hesitant to accelerate. The occurrence of hesitation impairs drivability, so it is desirable to suppress this.

[0048] The period from the start of engine 2 (cranking by a starter, not shown) until engine torque can be used as a driving source for traveling includes a period from the start of engine 2 starting until starting is completed (starting period) and a period during which the engine speed is increased to match the clutch speed and rotation matching is performed (rotation matching period). Furthermore, rotation matching of the engine speed to the clutch rotation speed is started on the condition that starting of engine 2 is completed.

[0049] The comparative example shown in Fig. 6 is a timing chart illustrating a case where the vehicle's responsiveness to the driver's requested torque deteriorates immediately after switching to the HEV mode. Fig. 6 shows the transition of the vehicle state when the driver downshifts the gear and presses the accelerator pedal 90 hard to accelerate the vehicle while in the EV mode, causing the vehicle to switch to the HEV mode.

[0050] 6, the vertical axis represents, from top to bottom, the gear position (referred to as "gear position" in the figure), clutch rotation speed, engine rotation speed, clutch pedal 71 depression state (referred to as "clutch pedal" in the figure), actual clutch position, accelerator opening, axle torque demand after clutch limit, motor torque (referred to as "motor output torque" in the figure), axle torque, and driving mode, while the horizontal axis represents time. Note that the axle torque demand after clutch limit is represented by a solid line, the motor torque by a dashed line, and the axle torque by a dashed line.

[0051] In an initial state before time t11, the vehicle 1 is traveling in EV mode. In this EV mode, the clutch pedal 71 is in a released position (denoted as "released" in the figure) where it is not depressed, but the actual clutch position is maintained in a disengaged position (denoted as "open" in the figure) by the drive of the clutch actuator 70. Furthermore, because the engine 2 is not operating, the engine speed is maintained at zero. Furthermore, the gear position is set to fifth gear, and the accelerator opening is maintained at a constant opening (for example, 50%). Furthermore, the axle request torque after clutch limiting, which is the driver request torque, is satisfied by the motor torque, and the value of the axle torque is the same as the motor torque.

[0052] Thereafter, the driver performs a downshift operation to accelerate the vehicle 1 by depressing the clutch pedal 71 to the press position (denoted as press in the figure), which is the position where it is depressed to the maximum, at time t11, shifting the gear to neutral at time t12, shifting the gear to third gear (or fourth gear) at time t13, and beginning to return the clutch pedal 71 to the release position, and finishing returning the clutch pedal 71 to the release position at time t15.

[0053] Then, at time t14 while the clutch pedal 71 is being released, the motor torque reaches the motor output torque, and the axle torque requirement after clutch limiting cannot be met by the motor torque alone. Therefore, at time t14, the EV mode is switched to the HEV mode, and the engine 2 begins to start (crank).

[0054] Then, at time t15, starting of engine 2 is completed. After starting of engine 2 is completed, the engine speed is increased to match the clutch speed. Then, at time t16, the engine speed matches the clutch speed, and the speed matching is completed.

[0055] Then, at time t17, the clutch 7 is engaged by driving the clutch actuator 70, and the actual clutch position is set to the engaged position (denoted as closed in the figure). As a result, at time t17, the shortage of motor torque relative to the axle request torque after clutch limiting can be compensated for by engine torque.

[0056] 6, engine torque cannot be used as a driving source for traveling during the period from when the mode is switched to HEV mode at time t14 until the clutch 7 is fully engaged at time t17, resulting in a shortage of axle torque relative to the axle request torque after the clutch is limited, and the responsiveness of the vehicle 1 to the driver request torque deteriorates. In other words, a hedging occurs immediately after switching to HEV mode.

[0057] Therefore, in this embodiment, in order to suppress deterioration in the vehicle's responsiveness to the driver's requested torque immediately after switching from the EV mode to the HEV mode, when the driver performs an operation that is expected to switch to the HEV mode, the engine 2 is started in advance prior to switching to the HEV mode. An operation that is expected to switch to the HEV mode is a predetermined operation that is expected to make it impossible to satisfy the driver's requested torque with the motor torque.

[0058] Here, a predetermined operation that is expected to cause the motor torque to be unable to satisfy the driver's requested torque is a driving operation that requires large acceleration, such as for overtaking a preceding vehicle. An example of a driving operation that requires large acceleration is an operation of downshifting the gear position by two or more steps to a lower gear position (for example, a jump shift from fifth gear to third gear) and depressing the accelerator pedal 90. In this embodiment, the operation of the ECU 10 when this operation is performed will be described. Note that another driving operation that requires large acceleration is an operation of downshifting the gear position by one step to a lower gear position (for example, a jump shift from fifth gear to fourth gear) and depressing the accelerator pedal 90 more deeply, and the operation of the ECU 10 when this operation is performed will be described in a second embodiment.

[0059] In this embodiment, even in the EV mode, the ECU 10 starts the engine 2 when a predetermined operation is performed that involves at least one of a shift operation and a clutch operation on the clutch pedal 71, and that is expected to cause the motor torque to be unable to satisfy the driver's requested torque. The predetermined operation is a shift operation to downshift to a gear that is two or more steps lower. For example, the predetermined operation is a shift operation to downshift from fifth gear to third gear.

[0060] However, even if a specified operation involving at least one of a shift operation or a clutch operation on the clutch pedal 71 is being performed, if a brake operation is also being performed, the driver is performing an operation to decelerate the vehicle 1, and it is not an operation that is expected to result in the motor torque being unable to satisfy the driver's required torque.

[0061] Therefore, even if a predetermined operation is performed during the EV mode, the ECU 10 does not start the engine 2 if the brake pedal 92 is also being operated to brake.

[0062] The transition of the vehicle state during operation of the vehicle control device according to this embodiment configured as described above will be described with reference to the timing chart of FIG. 2. FIG. 2 shows the transition of the vehicle state when, in EV mode, the driver downshifts the gear by two or more steps to a lower gear in order to accelerate the vehicle rapidly and depresses the accelerator pedal 90, causing the engine 2 to start prior to switching to HEV mode. The vertical axis of FIG. 2 represents, from top to bottom, the gear, clutch rotation speed, engine rotation speed, clutch pedal 71 depression state (referred to as "clutch pedal" in the figure), actual clutch position, accelerator opening, axle torque demand after clutch limit, motor torque (referred to as "motor output torque" in the figure), axle torque, and driving mode, while the horizontal axis represents the transition of time. The axle torque demand after clutch limit is represented by a solid line, the motor torque by a dashed line, and the axle torque by a dashed line.

[0063] In the initial state before time t21, the vehicle 1 is running in EV mode. In this EV mode, the clutch pedal 71 is not depressed and is in the release position (denoted as "released" in the figure), but the actual clutch position is maintained in the open position (denoted as "open" in the figure) by the drive of the clutch actuator 70. In addition, because the engine 2 is not operating, the engine speed is maintained at zero. In addition, the gear position is set to fifth gear, and the accelerator opening is maintained at a constant opening (for example, 50%). In addition, the axle request torque after clutch limiting, which is the driver request torque, is satisfied by the motor torque, and the value of the axle torque is the same as the motor torque.

[0064] Thereafter, the driver depresses the clutch pedal 71 to the press position (denoted as press in the figure), which is the position where it is depressed to the maximum, at time t21 as a downshift operation to accelerate the vehicle 1, shifts the gear from 5th gear to neutral at time t22, shifts the gear from neutral to 3rd gear at time t23, and begins to return the clutch pedal 71 to the release position, and finishes returning the clutch pedal 71 to the release position at time t25.

[0065] Then, at time t24 while the clutch pedal 71 is being released, the motor torque reaches the motor output torque, and the axle request torque after clutch limiting cannot be satisfied by the motor torque alone. Therefore, at time t24, the ECU 10 switches from the EV mode to the HEV mode.

[0066] At time t23, which is the timing before switching to HEV mode, ECU 10 starts starting engine 2 (referred to as cranking in the figure) in response to the gear shift from neutral to third gear.

[0067] Then, at time t24, starting of engine 2 is completed. Then, since starting of engine 2 is completed, ECU 10 increases the engine speed to match the clutch speed. Then, at time t25, the engine speed matches the clutch speed, and the speed matching is completed.

[0068] Then, at time t26, the ECU 10 drives the clutch actuator 70 to engage the clutch 7. As a result, the actual clutch position is set to the engaged position (denoted as closed in the figure). Since the clutch position is set to the engaged position, at time t26, the shortage of motor torque relative to the axle request torque after clutch limiting can be compensated for by engine torque.

[0069] Therefore, in this embodiment, the period in which the hedging occurs immediately after switching to the HEV mode does not include the period from the start (time t23) to the completion (time t24) of starting the engine 2, but only the period from the start (time t24) to the completion (time t25) of rotation matching of the engine 2. This makes it possible to suppress deterioration in the responsiveness of the vehicle 1 to the driver's requested torque immediately after switching from the EV mode to the HEV mode.

[0070] As described above, in this embodiment, even during EV mode, the ECU 10 initiates starting of the engine 2 when a predetermined operation is performed that involves at least one of a shift operation or a clutch operation on the clutch pedal 71, and that is expected to result in the motor torque being unable to satisfy the driver's required torque.

[0071] As a result, if the driver performs a predetermined operation that is expected to cause the motor torque to be unable to satisfy the driver requested torque, the engine 2 is started in advance before switching to the EV mode.

[0072] Therefore, the engine 2 can be started up before switching to the EV mode, and the shortage of motor torque relative to the driver's requested torque can be compensated for by the engine torque immediately after switching to the EV mode. As a result, the shortage of engine torque and the period of shortage can be reduced immediately after switching to the EV mode, and the occurrence of so-called hedging can be suppressed.

[0073] As a result, it is possible to suppress deterioration in the responsiveness of the vehicle to the driver's requested torque immediately after switching from the EV mode to the HEV mode.

[0074] In this embodiment, the predetermined operation is a downshift operation to a gear position that is two or more steps lower.

[0075] As a result, if the driver desires greater acceleration of the vehicle 1, disengages the clutch 7, downshifts the gear from fifth gear to third gear, and engages the clutch while depressing the accelerator pedal 90, the engine 2 starts to start at the timing when the downshift to third gear is performed. Therefore, the engine 2 can be started up by the time the mode is switched to the HEV mode based on the engagement of the clutch 7.

[0076] Therefore, it is possible to suppress deterioration in the responsiveness of the vehicle to the driver's requested torque immediately after switching from the EV mode to the HEV mode.

[0077] Furthermore, in this embodiment, even if a predetermined operation is performed during the EV mode, the ECU 10 does not start the engine 2 if the brake pedal 92 is also being operated to brake.

[0078] In this way, downshifting accompanied by braking is not an operation for accelerating the vehicle, but an operation for transitioning to a stop, and since it is not expected that the vehicle will transition to HEV mode due to an increase in driver-requested torque, deterioration in fuel efficiency can be avoided by not starting engine 2 unnecessarily. [Example]

[0079] Next, a vehicle control device according to a second embodiment will be described. In this embodiment, the operation of the ECU 10 in the vehicle 1 having the configuration shown in Fig. 1 is partially different. The following describes the differences from the first embodiment.

[0080] One driving operation that may result in switching to HEV mode is when, while driving in EV mode, the driver performs a driving operation that requires high acceleration, such as to overtake a preceding vehicle.Driving operations that require high acceleration include downshifting the gear by one gear to a lower gear (for example, from 5th gear to 4th gear) and depressing the accelerator pedal 90 more firmly.

[0081] In this embodiment, the predetermined operation is defined as a clutch operation and an accelerator operation of the accelerator pedal 90 that is equal to or greater than a predetermined threshold value, performed simultaneously.

[0082] Here, the driver may operate the accelerator pedal 90 by an amount equal to or greater than a predetermined threshold, not for the purpose of accelerating the vehicle 1 but for the purpose of matching the engine rotation speed during a downshift. For example, during a downshift operation, the driver may perform an operation (blipping) of depressing the accelerator pedal 90 for a short period of time in order to match the engine rotation speed to the clutch rotation speed. This blipping is an operation intended to smoothly shift gears in the manual transmission 4, and is not an operation intended to accelerate the vehicle 1. Furthermore, in the vehicle 1 of this embodiment, operation of the engine 2 is stopped during the EV mode, making blipping unnecessary, but unnecessary blipping may be performed out of the driver's habit.

[0083] Therefore, even if a predetermined operation is performed during EV mode, the ECU 10 is configured not to start the engine 2 if the time during which the amount of accelerator operation is equal to or greater than a predetermined threshold is less than a predetermined time.

[0084] The transition of the vehicle state during operation of the vehicle control device according to this embodiment configured as described above will be described with reference to the timing chart of FIG. 3. FIG. 3 shows the transition of the vehicle state when, in EV mode, the driver downshifts the gear to a gear one step lower in order to accelerate the vehicle more rapidly and also deeply depresses the accelerator pedal 90, causing the engine 2 to start prior to switching to HEV mode. The vertical axis of FIG. 3 represents, from top to bottom, the gear, clutch rotation speed, engine rotation speed, clutch pedal 71 depression state (referred to as "clutch pedal" in the figure), actual clutch position, accelerator opening, axle torque demand after clutch limit, motor torque (referred to as "motor output torque" in the figure), axle torque, and driving mode, while the horizontal axis represents the transition of time. The axle torque demand after clutch limit is represented by a solid line, the motor torque by a dashed line, and the axle torque by a dashed line.

[0085] In an initial state before time t31, the vehicle 1 is running in EV mode. In this EV mode, the clutch pedal 71 is not depressed and is in a released position (denoted as "released" in the figure), but the actual clutch position is maintained in a disengaged position (denoted as "open" in the figure) by the drive of the clutch actuator 70. Furthermore, because the engine 2 is not operating, the engine speed is maintained at zero. Furthermore, the gear position is set to fifth gear, and the accelerator opening is maintained at a constant opening (for example, 50%). Furthermore, the axle request torque after clutch limiting, which is the driver request torque, is satisfied by the motor torque, and the value of the axle torque is the same as the motor torque.

[0086] Thereafter, the driver depresses the clutch pedal 71 to the press position (denoted as press in the figure), which is the position where it is depressed to the maximum, at time t31 as a downshift operation to accelerate the vehicle 1, shifts the gear from 5th gear to neutral at time t32, shifts the gear from neutral to 4th gear at time t34, and begins to return the clutch pedal 71 to the release position, and finishes returning the clutch pedal 71 to the release position at time t37.

[0087] Then, at time t35 while the clutch pedal 71 is being released, the motor torque reaches the motor output torque, and the axle request torque after clutch limiting cannot be satisfied by the motor torque alone. Therefore, at time t35, the ECU 10 switches from the EV mode to the HEV mode.

[0088] At time t33, which is the timing before switching to the HEV mode, the accelerator opening has increased to or above the accelerator opening threshold, which is a predetermined threshold. Therefore, because the clutch operation and the accelerator operation on the accelerator pedal 90 that is equal to or greater than the predetermined threshold have been performed simultaneously, the ECU 10 starts the engine 2 (referred to as cranking in the drawing) at time t33.

[0089] Thereafter, the start of the engine 2 is completed, and at time t36, the engine rotation speed matches the clutch rotation speed, completing rotation speed matching.

[0090] Then, at time t37, the ECU 10 drives the clutch actuator 70 to engage the clutch 7. This causes the actual clutch position to be the engaged position (denoted as closed in the figure). Therefore, at time t37, the shortage of motor torque relative to the axle request torque after clutch limiting can be compensated for by engine torque.

[0091] Therefore, in this embodiment, the period in which the hedging occurs immediately after switching to the HEV mode does not include the period from the start of starting the engine 2 (time t33) to the timing of switching to the HEV mode (time t35), but only the period from the timing of switching to the HEV mode (time t35) to the completion of rotation matching (time t37) of the engine 2. This makes it possible to suppress deterioration in the responsiveness of the vehicle 1 to the driver's requested torque immediately after switching from the EV mode to the HEV mode.

[0092] Figure 4 shows the transition of the vehicle state when the driver downshifts to a gear one step lower and blips the accelerator pedal 90 to decelerate the vehicle while coasting in EV mode. The vertical axis of Figure 4, from top to bottom, represents the gear, clutch rotation speed, engine rotation speed, clutch pedal 71 depression state (referred to as clutch pedal in the figure), actual clutch position, accelerator opening, axle torque demand after clutch limit, motor torque (referred to as motor output torque in the figure), axle torque, and driving mode, while the horizontal axis represents the transition of time. The axle torque demand after clutch limit is represented by a solid line, the motor torque by a dashed line, and the axle torque by a dashed line.

[0093] In an initial state before time t41, the vehicle 1 is running in EV mode. In this EV mode, the clutch pedal 71 is not depressed and is in a released position (denoted as "released" in the figure), but the actual clutch position is maintained in a disengaged position (denoted as "open" in the figure) by the drive of the clutch actuator 70. In addition, because the engine 2 is stopped, the engine speed is maintained at zero. In addition, the gear position is set to fifth gear, and the accelerator opening is maintained at a constant opening (for example, 0%). In addition, the axle request torque after clutch limiting, which is the driver request torque, is satisfied by the motor torque, and the value of the axle torque is the same as the motor torque.

[0094] Thereafter, in order to decelerate the vehicle 1, the driver begins to depress the clutch pedal 71 to the press position (denoted as press in the figure) at time t41, finishes depressing the clutch pedal 71 at time t42, shifts the gear from 5th gear to neutral at time t43, shifts the gear from neutral to 4th gear at time t44, and begins to return the clutch pedal 71 to the release position, and finishes returning the clutch pedal 71 to the release position at time t46.

[0095] At time t44 when the gear is still in neutral, the driver's blipping causes the accelerator opening to exceed the accelerator opening threshold for a short period of time. The accelerator opening remains above the accelerator opening threshold from time t44 for a period T1 that is shorter than the predetermined time.

[0096] 4, the predetermined operations during the EV mode are a clutch operation and an accelerator operation of the accelerator pedal 90 equal to or greater than a predetermined threshold. However, because the time during which the accelerator operation amount is equal to or greater than the predetermined threshold is shorter than the predetermined time, the engine 2 does not start.

[0097] Here, the accelerator opening (depression amount of accelerator pedal 90) is detected by a "look-ahead" method that estimates the accelerator opening after a desired look-ahead period, and the "look-ahead value" obtained by this look-ahead method can be used as the value of the accelerator opening after the look-ahead period from the present time. A known method can be used to estimate the look-ahead value of the accelerator opening.

[0098] A method for estimating the accelerator opening read-ahead value can be as shown in FIG. 5. In FIG. 5, the vertical axis represents the accelerator opening, and the horizontal axis represents the transition of time. As shown in FIG. 5, the estimated value of the accelerator opening at time P5 after a desired look-ahead period from current time P4 can be calculated by multiplying the average value of the change in accelerator opening (% / ms) between points P1, P2, and P3 during a predetermined time period (30 ms in FIG. 5) prior to current time P4 by the look-ahead period, and adding this multiplied value to the accelerator opening at current point P4. By determining whether to start engine 2 based on the look-ahead value of the accelerator opening instead of the actual accelerator opening, the driver's intention can be detected at an earlier timing, and engine 2 can be started at an earlier timing, thereby further reducing the occurrence of hesitation.

[0099] As described above, in this embodiment, the predetermined operation is the simultaneous clutch operation and accelerator operation of the accelerator pedal 90 by an amount equal to or greater than a predetermined threshold.

[0100] As a result, when the driver desires to accelerate the vehicle 1, performs an operation to release the clutch, downshifts the gear from fifth gear to fourth gear, and engages the clutch 7 while depressing the accelerator pedal 90 to a level equal to or greater than a predetermined threshold, starting of the engine 2 is initiated at the timing when the accelerator pedal 90 is depressed to a level equal to or greater than the predetermined threshold. Therefore, when switching to the HEV mode is performed based on the engagement of the clutch 7, starting of the engine 2 can be completed.

[0101] In addition, in this embodiment, even if a predetermined operation is performed during EV mode, the ECU 10 will not initiate starting of the engine 2 if the time during which the amount of accelerator operation is greater than or equal to a predetermined threshold is less than a predetermined time.

[0102] As a result, blipping, which is an operation of depressing the accelerator pedal 90 for a short period of time during a downshift operation, is not an operation for accelerating the vehicle 1, but an operation for smoothly changing the gear ratio, and since it is not expected that the vehicle will transition to HEV mode due to an increase in driver-requested torque, it is possible to avoid a deterioration in fuel efficiency due to unnecessary starting of the engine 2.

[0103] While an embodiment of the present invention has been disclosed, it will be apparent to one skilled in the art that modifications may be made thereto without departing from the scope of the present invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0104] 1 vehicle 2 engines 3 Motor generator (motor) 4 Manual Transmission 7. Clutch 10 ECU (control unit) 40 Shift lever 70 Clutch actuator 71 Clutch pedal 90 Accelerator pedal 92 Brake pedal

Claims

1. an engine that generates engine torque; a motor that generates a motor torque; a manual transmission disposed between the engine and the motor, the manual transmission being adapted to change gear positions by a shift operation on a shift lever; a clutch disposed between the engine and the manual transmission, the clutch being disengaged or engaged by operation of a clutch actuator; an EV mode in which the engine is stopped, the clutch is released, and the vehicle travels while satisfying the driver's requested torque with the motor torque; an HEV mode in which the engine is operated, the clutch is engaged, and the driver requested torque is satisfied by at least the engine torque of the engine torque and the motor torque; A control device for a vehicle including a control unit that switches to the HEV mode when the driver requested torque cannot be satisfied by the motor torque in the EV mode, The control unit Even during the EV mode, when a predetermined operation is performed that involves at least one of the shift operation and the clutch operation on the clutch pedal and that is expected to cause the motor torque to be unable to satisfy the driver's requested torque, the engine is started, 10. A vehicle control device, wherein the predetermined operation is a shift operation for downshifting to a gear position that is two or more steps lower.

2. The control unit 2. The vehicle control device according to claim 1, wherein even if the predetermined operation is performed during the EV mode, if a brake pedal operation is also being performed, the engine start is not initiated.

3. An engine that generates engine torque; a motor that generates a motor torque; a manual transmission disposed between the engine and the motor, the manual transmission being adapted to change gear positions by a shift operation on a shift lever; a clutch disposed between the engine and the manual transmission, the clutch being disengaged or engaged by operation of a clutch actuator; an EV mode in which the engine is stopped, the clutch is released, and the vehicle travels while satisfying the driver's requested torque with the motor torque; an HEV mode in which the engine is operated, the clutch is engaged, and the driver requested torque is satisfied by at least the engine torque of the engine torque and the motor torque; A control device for a vehicle including a control unit that switches to the HEV mode when the driver requested torque cannot be satisfied by the motor torque in the EV mode, The control unit Even during the EV mode, when a predetermined operation is performed that involves at least one of the shift operation and the clutch operation on the clutch pedal and that is expected to cause the motor torque to be unable to satisfy the driver's requested torque, the engine is started, The vehicle control device is characterized in that the predetermined operation is the clutch operation and an accelerator pedal operation of an amount equal to or greater than a predetermined threshold value performed simultaneously.

4. The control unit 4. The vehicle control device according to claim 3, wherein even if the predetermined operation is performed during the EV mode, if the time during which the amount of accelerator operation is equal to or greater than the predetermined threshold is less than a predetermined time, the engine is not started.

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