ENGINE TORQUE CONTROL DEVICE FOR HYBRID VEHICLES

Abstract

A motor torque control device for a hybrid vehicle (1) in which a drive motor (2) and a motor generator (3) are connected to each other via an automatic clutch (7) and the motor generator (3) and a transmission (4) are connected to each other via a manual clutch (8), wherein a control mode of the hybrid vehicle (1) comprises an EV mode in which the automatic clutch (7) is disengaged to cause the hybrid vehicle (1) to drive by power from the motor generator (3), and an HEV mode in which the automatic clutch (7) is engaged to cause the hybrid vehicle (1) to drive by power from the drive motor (2) or by power from the drive motor (2) and the motor generator (3), wherein the engine torque control device has a control unit (10) configured to switch between EV mode and HEV mode based on a driver request torque calculated based on at least one accelerator opening degree, wherein the control unit (10) corrects a torque of the motor generator (3) such that a rate of change of speed of the motor generator (3) in the EV mode and a rate of change of speed of the motor generator (3) in the HEV mode are within a range.

Description

[Technical field]

[0001] The present invention relates to an engine torque control device for a hybrid vehicle. [Technical background]

[0002] JP 2013 - 184 689 A discloses a hybrid vehicle in which an engine / generator and a manual transmission are provided on a power transmission path leading from a drive machine to drive wheels, an automatic clutch is provided between the drive machine and the engine / generator, and a manual clutch is provided between the engine and the manual transmission.

[0003] DE 11 2007 000 564 B4 discloses a vehicle comprising: an internal combustion engine; a mechanism for supplying / distributing electrical / mechanical power, connected to a first axle, which is one of the axles of the vehicle, and to an output shaft of the internal combustion engine, and capable of supplying / distributing power to / from the first axle and the output shaft with a supply / distribution of electrical and mechanical power; a motor capable of supplying / distributing power; a transmission mechanism connected to the first axle or a second axle, which is an axle other than the first axle, and to a rotating shaft of the motor, in order to transmit power between the second axle and the rotating shaft by shifting a plurality of gears;a storage unit capable of exchanging electrical power with the electrical / mechanical power supply / output mechanism and the motor; a unit for adjusting a required motive force to set a motive force necessary for driving; and a control unit for controlling the internal combustion engine, the electrical / mechanical power supply / output mechanism, and the motor such that driving is effected by a motive force starting from the required motive force set as above, with a change within a first rate of change of rotation of the internal combustion engine. [State of the art][Patent literature] [Patent literature 1] JP 2013 - 184 689 A [Patent literature 2] DE 11 2007 000 564 B4 [Summary of the invention][Technical problem]

[0004] In such a hybrid vehicle, during EV mode, where only the engine / generator is used as the power source, only the engine / generator is connected to the drive wheels, and therefore the moment of inertia of the engine / generator is present. In HEV mode, where both the engine and the engine / generator are used as power sources, the engine and the engine / generator are connected to the drive wheels, and thus both the moment of inertia of the engine and the moment of inertia of the engine / generator are present. Comparing the moment of inertia in EV mode with that in HEV mode, the moment of inertia in EV mode is lower, resulting in a relatively higher rate of rotational speed change of the engine / generator in EV mode.

[0005] Due to this difference in moment of inertia, the acceleration / deceleration of the hybrid vehicle tends to increase more in EV mode than in HEV mode. Even if the driver performs the same driving action in both EV and HEV modes, the vehicle's behavior in response to the driver's input differs in each mode, potentially causing the driver to experience an uncomfortable sensation. In particular, synchronizing the engine / generator speed with the transmission input speed is challenging at the time of gear changes, and therefore, the vehicle's behavior may vary between EV and HEV modes.

[0006] The present invention was made in view of the above considerations and it is an object of the present invention to provide an engine torque control device for a hybrid vehicle, wherein the engine torque control device can prevent the situation in which the vehicle behavior differs significantly between different control modes in response to a driving operation performed by the driver. [Solution to the problem]

[0007] To solve the aforementioned problems, the present invention provides an engine torque control device for a hybrid vehicle according to independent claim 1. Advantageous modifications are described in the dependent claims. [Advantageous effect of the invention]

[0008] As described above, the present invention makes it possible to prevent the vehicle's behavior from differing noticeably between different control modes in response to a driving action performed by the driver. [Brief description of the drawings] Fig. Figure 1 is a schematic representation of the configuration of a hybrid vehicle according to an embodiment of the present invention. Fig. Figure 2 is a diagram showing examples of mappings for calculating driver request torques referenced by an ECU attached to the hybrid vehicle according to the embodiment of the present invention. Fig. Figure 3 is a flowchart showing the process of processing an engine torque control carried out by the ECU attached to the hybrid vehicle according to the present invention. Fig. Figure 4 is a time diagram showing changes in torque command values ​​and speed of a motor generator when the gear stage of a manual transmission is shifted from first gear to second gear during acceleration in the processing of the engine torque control of the hybrid vehicle in the embodiment of the present invention. Fig. Figure 5 is a time diagram showing changes in the torque command values ​​and the speed of the motor generator when the gear stage of the manual transmission is shifted from the third gear stage to the second gear stage during the delay in processing the engine torque control of the hybrid vehicle according to the embodiment of the present invention. Fig. Figure 6 is a flowchart showing the process of processing the engine torque control, which is carried out by the ECU attached to a hybrid vehicle according to a first modification of the present embodiment of the present invention. Fig. Figure 7 is a flowchart showing the process of processing the engine torque control, which is carried out by the ECU attached to a hybrid vehicle according to a second modification of the present embodiment of the invention. Fig. Figure 8 is a flowchart showing the process of processing the engine torque control, which is carried out by the ECU attached to a hybrid vehicle according to a third modification of the present embodiment of the invention. [Description of the embodiment]

[0009] An engine torque control device according to an embodiment of the present invention is attached to a hybrid vehicle in which a drive unit and an engine are connected to each other via an automatic clutch and the engine and a transmission are connected to each other via a manual clutch, wherein a control mode of the hybrid vehicle comprises an EV mode in which the automatic clutch is disengaged to cause the hybrid vehicle to drive by the power of the engine, and an HEV mode in which the automatic clutch is engaged to cause the hybrid vehicle to drive by power from the drive unit or by power from the drive unit and the engine, wherein the engine torque control device has a control unit configured to switch between the EV mode and the HEV mode based on a driver request torque.which is calculated based on at least one accelerator opening degree, whereby the control unit corrects a torque of the motor such that a rate of change of a speed of the motor in the EV mode is essentially equal to a rate of change of a speed of the motor in the HEV mode.

[0010] With such a configuration, the engine torque control device for a hybrid vehicle according to an embodiment of the present invention can prevent the situation in which the behavior of the vehicle in response to a driving operation performed by the driver differs remarkably between different control modes. [Version]

[0011] A hybrid vehicle to which an engine torque control device according to an embodiment of the present invention is attached is described in detail below with reference to the drawings.

[0012] In Fig. 1 comprises a hybrid vehicle 1 according to an embodiment of the present invention, comprising a drive machine 2, a motor generator 3 serving as a motor, a manual transmission 4 serving as a transmission, a differential gear 5, drive wheels 6 and an electrical control unit (ECU) 10 serving as a control unit.

[0013] The drive machine 2 has a plurality of cylinders. In this embodiment, the drive machine 2 is configured to perform a series of four strokes for each cylinder, comprising an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke.

[0014] The motor generator 3 has a function as an electric motor, driven by electrical power supplied by a battery 31 via an inverter 30, and a function as a generator, producing power by a driving force input from the manual gearbox 4 or from the drive machine 2.

[0015] Under the control of the ECU 10, the inverter 30 converts DC power supplied by the battery 31 into three-phase AC power to supply the three-phase AC power to the motor generator 3, or converts three-phase AC power generated by the motor generator 3 into DC power to charge the battery 31.

[0016] Battery 31 can be a secondary battery, for example a lithium-ion battery.

[0017] The manual transmission 4 is designed as a manual transmission or gearbox, which modifies and outputs the rotation generated either by the drive motor 2 or the motor-generator 3, or by both, with a gear ratio corresponding to any one of a plurality of gear stages. The manual transmission 4 is connected to the left and right drive wheels 6 via the differential 5.

[0018] The four gear ratios achievable through the manual transmission include driving gears and reverse, with the gear ratios ranging, for example, from first gear (low range) to fifth gear (high range). The number of driving gears varies depending on various elements of the hybrid vehicle and is not limited to the aforementioned first through fifth gears.

[0019] The gear of the manual transmission 4 can be shifted according to the operating position of a shift lever 40 operated by the driver. The operating position of the shift lever 40 is detected by a shift position sensor 41. The shift position sensor 41 is connected to the ECU 10 and is configured to transmit the detection result to the ECU 10.

[0020] The manual gearbox 4 is equipped with a neutral switch 42.

[0021] The neutral switch 42 is connected to the ECU 10. The neutral switch 42 is a switch that detects a state in which none of the gear stages are engaged by the manual transmission 4, i.e., a state in which the manual transmission 4 is in neutral, and which is activated when the manual transmission 4 is in neutral.

[0022] A power transmission path between a drive machine 2 and the motor-generator 3 is equipped with an automatic coupling 7. A friction coupling, for example, can be used for the automatic coupling 7. The drive machine 2 and the motor-generator 3 are connected to each other via the automatic coupling 7.

[0023] The automatic clutch 7 is actuated by a clutch actuator 70 and can switch between an engaged state, in which power is transferred between a drive machine 2 and the motor-generator 3, and a disengaged state, in which no power is transferred between the drive machine 2 and the motor-generator 3. The clutch actuator 70 is connected to the ECU 10 and is configured to be controlled by the ECU 10.

[0024] A power transmission path between the motor-generator 3 and the manual transmission 4 is equipped with a manual clutch 8. The motor-generator 3 and the manual transmission 4 are connected to each other via the manual clutch 8.

[0025] The manual clutch 8 is a mechanical clutch that is actuated depending on the range of action of a clutch pedal 80 operated by the driver. A friction clutch, for example, can be used for the manual clutch 8.

[0026] The range of action of the clutch pedal 80 is detected by a clutch pedal sensor 81.

[0027] The clutch pedal sensor 81 is connected to the ECU 10 and is configured to transmit a signal to the ECU 10 corresponding to the actuation range of the clutch pedal 80.

[0028] If the actuation range of the clutch pedal 80 is less than the predetermined clutch engagement threshold, the ECU 10 determines that the manual clutch 8 is engaged. If the actuation range of the clutch pedal 80 is greater than the predetermined clutch release threshold, the ECU 10 determines that the manual clutch 8 is disengaged.

[0029] The hybrid vehicle 1 includes an accelerator pedal (gas pedal) 90, which is operated by the driver. The actuation range of the accelerator pedal 90 is detected by an accelerator opening sensor 91. The accelerator opening sensor 91 is connected to the ECU 10. The accelerator opening sensor 91 is configured to detect the actuation range of the accelerator pedal 90 as the accelerator opening degree and is configured to transmit a signal corresponding to the accelerator opening degree to the ECU 10.

[0030] The ECU 10 consists of a computer unit that includes a central processing unit (CPU), a random access memory (RAM), a read-only memory (ROM), a flash memory that stores backup data and other data, an input port and an output port.

[0031] The computer unit's ROM contains a program that causes the computer unit to function as ECU 10, along with various constants, assignments, and the like. In other words, in this embodiment, the computer unit functions as ECU 10 when the CPU executes the program stored in the ROM, using RAM as its working area.

[0032] In addition to the sensors mentioned above, a vehicle speed sensor 11 is connected to the ECU 10. The vehicle speed sensor 11 is configured to detect the vehicle speed of the hybrid vehicle 1 and is configured to transmit the detection result to the ECU 10.

[0033] The ECU 10 is configured to control the control mode of the hybrid vehicle 1. In this embodiment, an EV mode and an HEV mode are set as control modes.

[0034] EV mode is the control mode in which the automatic clutch 7 is disengaged and the hybrid vehicle 1 is propelled by power from the motor-generator 3. HEV mode is the control mode in which the automatic clutch 7 is engaged and the hybrid vehicle 1 is propelled by power from the drive motor 2 or by power from the drive motor 2 and the motor-generator 3.

[0035] The ECU 10 is configured to switch between EV mode and HEV mode according to the accelerator opening degree detected by the accelerator opening sensor 91 and the speed of the motor generator 3 (hereinafter referred to as "MG speed").

[0036] The ECU 10 calculates the driver request torque, for example, based on the accelerator opening degree and the engine speed. The ECU 10 calculates the driver request torque using the information in Fig. 2. The assignment shown, in which the driver request torque is determined, for example, by the accelerator opening degree and the MG speed. In Fig. 2 is the value on the right side of each "APS =" which is the accelerator opening degree, and the line on the left side of each "APS =" is the mapping used to calculate the driver request torque for the accelerator opening degree. The ECU 10 can calculate the driver request torque using a mapping where, for example, the driver request torque is determined by the accelerator opening degree.

[0037] For example, the ECU 10 switches between EV mode and HEV mode based on the driver's torque demand.

[0038] In this embodiment, the ECU 10 corrects the torque of the motor generator 3 such that the motor speed change rate, i.e., the amount of change in motor speed per unit of time, is essentially equal to the motor speed change rate in the HEV mode in EV mode. In this embodiment, "essentially equal" means that the motor speed change rate in EV mode and the motor speed change rate in HEV mode, for example, lie within a predetermined range. Furthermore, "essentially equal" means that the motor speed change rates in the modes fall within a range that prevents the vehicle's behavior in response to a driving input from differing noticeably between EV mode and HEV mode.

[0039] In EV mode, for example, the ECU 10 reduces the torque of the motor generator 3 by a larger amount when the MG speed change rate increases.

[0040] In EV mode, for example, the ECU 10 subtracts the MG correction torque, calculated using the following formula (1), from the driver request torque and uses the obtained value as the MG torque command value, which is a torque command value for the motor generator 3. MG correction torque [Nm]=moment of inertia [kgm2] of the drive machine×MG speed change rate [rad / s2]

[0041] The moment of inertia of the drive machine is the sum of the moments of inertia of components located on the side of the drive machine 2 and the automatic clutch 7, and is a fixed value for the hybrid vehicle 1.

[0042] This MG correction torque is a torque that corresponds to the moment of inertia generated due to the moments of inertia on the side of the drive machine 2 when the MG speed changes in a state in which the automatic clutch 7 is engaged.

[0043] A processing of an engine torque control, which is carried out by the engine torque control device according to this embodiment, which has the configuration mentioned above, is described with reference to Fig. 3 described. The processing of the engine torque control described below is started with the start of the action of ECU 10 and is executed at predefined time intervals.

[0044] In step S1, the ECU receives 10 different sensor information from the hybrid vehicle 1. After executing the process in step S1, the ECU 10 executes the process in step S2.

[0045] In step S2, the ECU 10 calculates the driver request torque Tdr by interpolating the data in Fig. The assignment shown in step 2 is based on the accelerator opening degree and the MG speed. After executing the operation in step S2, the ECU 10 executes the operation in step S3.

[0046] In step S3, ECU 10 determines whether the control mode of hybrid vehicle 1 is EV mode or not. If ECU 10 determines that the control mode of hybrid vehicle 1 is EV mode, it performs the processing in step S4. If ECU 10 determines that the control mode of hybrid vehicle 1 is not EV mode, it performs the processing in step S7.

[0047] In step S4, the ECU 10 calculates the MG speed change rate, which is the amount of change in MG speed per unit of time. After executing the processing in step S4, the ECU 10 executes the processing in step S5.

[0048] In step S5, the ECU 10 calculates the MG correction torque, which corresponds to the MG speed change rate, using the formula (1) mentioned above. After executing the processing in step S5, the ECU 10 executes the processing in step S6.

[0049] In step S6, ECU 10 subtracts the MG correction torque from the driver request torque Tdr and uses the resulting value as the MG torque command value. After completing the processing in step S6, ECU 10 terminates the engine torque control processing.

[0050] In step S7, the ECU 10 calculates the MG torque command value according to the control settings in HEV mode. In HEV mode, the moment of inertia on the power source side, i.e., on the side of the drive motor 2 and the manual clutch 8, corresponds to the moment of inertia of a normal internal combustion engine, so no moment of inertia correction control is performed. After completing the processing in step S7, the ECU 10 terminates the engine torque control processing.

[0051] Processes in such a processing of the engine torque control are described with reference to Fig. 4 and Fig. 5 described. Fig. Figure 4 shows the case where the gear of the manual transmission 4 is shifted from first gear to second gear during acceleration.

[0052] During a period from t0 to t1, the hybrid vehicle 1 travels in first gear with the accelerator pedal depressed to 90°. The driver request torque Tdr is derived from the in Fig. The assignment shown in 2 is calculated according to the accelerator opening degree and the MG rotational speed.

[0053] At time t1, the clutch pedal 80 begins to be depressed simultaneously with the start of the return stroke of the accelerator pedal 90. Then, at time t3, the manual clutch 8 is disengaged. The accelerator pedal 90 is fully returned to its resting position at time t3, so that the driver request torque Tdr assumes a negative value. Therefore, the engine speed at the power source begins to decrease.

[0054] In HEV mode, the moment of inertia at the power source is the sum of the moment of inertia of the drive machine 2 and the moment of inertia of the motor-generator 3. The moment of inertia of the motor-generator 3 is smaller than that of the drive machine 2, and therefore the rotational speed at the power source decreases with a reduction ratio close to that of a normal vehicle. Consequently, the gears of the manual transmission 4 are disengaged at time t4, and engagement occurs at time t6. Around time t7, when the manual clutch 8 begins to engage, the speed of the input shaft of the manual transmission 4 and the motor-generator speed are essentially synchronized, allowing the manual clutch 8 to achieve smooth engagement.

[0055] In contrast, the moment of inertia on the power source side in EV mode only includes the moment of inertia of the motor generator 3. Therefore, in the usual procedure, the rate of reduction of the rotational speed on the power source side increases, and at time t5 the rotational speed is reduced to a level corresponding to an idle speed, which is lower than a synchronized speed, where the rotational speed is synchronized with the speed of the input shaft of the manual transmission 4.

[0056] When the engine speed drops below idle speed, the driver request torque Tdr assumes a positive value, so the MG speed is maintained at the level corresponding to idle speed. When the manual clutch 8 begins to engage at time t7, the MG speed is increased to the speed of the input shaft of the manual transmission 4, resulting in a pulling jolt.

[0057] In this embodiment, the MG torque command value is corrected according to the MG speed change rate when EV mode is present. In the example in Fig. 4. Rotational synchronization is achieved by reducing the MG speed through the release of the accelerator, thus causing the MG speed change rate to assume a negative value. This value is multiplied by a value corresponding to the moment of inertia of the drive motor, and the resulting value is subtracted from the driver-requested torque Tdr to correct for this, thereby increasing the MG command value for torque and assuming a negative value close to zero. Therefore, the reduction rate of the MG speed decreases and thus becomes essentially the same as in HEV mode. Consequently, even if the engagement point of the manual clutch 8 in EV mode is essentially the same as in HEV mode, the MG speed can be effectively synchronized with the speed of the input shaft of the manual transmission 4, thus achieving smooth clutch engagement.

[0058] Fig. Figure 5 shows the case where the gear stage of the manual transmission 4 is switched from the third gear stage to the second gear stage during deceleration.

[0059] During a period from t10 to t11, the hybrid vehicle 1 travels in third gear with the accelerator pedal released at 90°. The driver request torque Tdr is derived from the in Fig. The assignment shown in Figure 2 is calculated according to the accelerator opening degree and the MG speed. In this case, the driver request torque Tdr assumes a negative value.

[0060] At time t11, in order to shift gears, the clutch pedal 80 begins to be depressed in a state in which the accelerator pedal 90 remains released. Subsequently, at time t13, the manual clutch 8 is moved into the disengaged state, so that the engine speed at the power source begins to decrease.

[0061] In HEV mode, the moment of inertia at the power source is the sum of the moment of inertia of drive machine 2 and the moment of inertia of motor-generator 3. Since the moment of inertia of motor-generator 3 is smaller than that of drive machine 2, the rotational speed at the power source decreases at a rate close to that of a normal vehicle. Therefore, the gears of manual transmission 4 are disengaged at time t14, the accelerator pedal 90 is depressed for rotational synchronization until time t15, and the clutch engages at time t16. Around time t17, when the manual clutch 8 is engaged, the speed of the input shaft of manual transmission 4 and the motor-generator speed are essentially synchronized, allowing the manual clutch 8 to achieve smooth engagement.

[0062] In contrast, the moment of inertia on the side of the power source in EV mode only includes the moment of inertia of the motor generator 3. Therefore, as shown by a line for a first typical EV mode in Fig. As shown in Figure 5, in the usual procedure, the rate of change of the rotational speed at the side of the power source increases, and at time t15 the rotational speed rises to a speed higher than the synchronized speed, at which the rotational speed is synchronized with the speed of the input shaft of the manual transmission 4. Since the accelerator pedal 90 is released, the MG rotational speed subsequently decreases but does not reach the synchronized speed. When the manual clutch 8 begins to engage at time t17, the MG rotational speed decreases to the speed of the input shaft of the manual transmission 4, and a shock occurs.

[0063] For example, how to add a line for a second usual EV mode in Fig. As shown in Figure 5, when the driver releases the accelerator pedal 90 at time t15' to effect rotational synchronization, by reducing the time interval while the accelerator pedal 90 is depressed, the MG speed is reduced to a level lower than the synchronized speed at time t17 when the manual clutch 8 begins to engage.

[0064] As described above, the motor generator 3 exhibits a large change in rotational speed, and therefore it is extremely difficult to generate rotational synchronization by actuating the accelerator.

[0065] In this embodiment, in the case of EV mode, the MG torque command value is corrected according to the MG speed change rate. In the example in Fig. 5. Rotational synchronization is performed by increasing the MG speed from time t14 to time t15 by actuating the accelerator, thus giving the MG speed change rate a positive value. This value is multiplied by a value corresponding to the moment of inertia of the drive motor, and the resulting value is subtracted from the driver request torque Tdr to correct for this, thereby decreasing the MG command value and giving it a positive value close to zero.

[0066] Therefore, the rate of increase of the MG speed decreases and thus becomes essentially the same as in HEV mode. Consequently, even if the engagement point of the manual clutch 8 in EV mode is essentially the same as in HEV mode, the MG speed can be synchronized essentially with the speed of the input shaft of the manual transmission 4, and thus a smooth clutch engagement can be achieved.

[0067] The description refers to the actions performed at the time of the gear shift. However, the rotational speed at the power source also changes at times other than gear shifting, such as when the hybrid vehicle accelerates or decelerates, and therefore the moment of inertia at the power source has an influence.

[0068] In particular, the moment of inertia on the side of the power source in EV mode is smaller than the moment of inertia on the side of the power source in HEV mode. Therefore, even if both EV and HEV modes are in the same gear of the 4-speed manual transmission and have the same accelerator pedal opening, EV mode will have greater acceleration and deceleration.

[0069] In this embodiment, in EV mode, a torque corresponding to a moment of inertia generated by the moment of inertia of the drive motor 2 is subtracted from the driver-requested torque for correction purposes. Therefore, acceleration / deceleration can also be achieved in EV mode that is essentially equivalent to the acceleration / deceleration in HEV mode.

[0070] As described above, in this embodiment the ECU 10 corrects the torque of the motor generator 3 such that the MG speed change rate, i.e. the amount of change in MG speed per unit of time, in EV mode is essentially equal to the MG speed change rate in HEV mode.

[0071] With such a correction, the torque of motor-generator 3 is adjusted so that the motor speed change rate in EV mode is essentially the same as the motor speed change rate in HEV mode. Therefore, there is no possibility that EV mode and HEV mode will exhibit significantly different degrees of acceleration / deceleration in response to the driver's input, thus preventing a situation where the vehicle's behavior differs noticeably due to the difference in control mode.

[0072] In addition to the above, if the driver performs the same actions for both EV and HEV modes, at the moment of gear shifting in manual transmission 4, both modes will have essentially the same rotational speed output by motor generator 3 to the input shaft of manual transmission 4. Therefore, there is no possibility of the EV and HEV modes exhibiting significantly different vehicle behavior, and thus smooth gear changes can be achieved even if the driver does not understand the characteristics of the control mode.

[0073] Furthermore, even at times other than gear changes, the driver can experience the same degree of acceleration / deceleration in relation to the driver's actions (clutch pedal 80, accelerator pedal 90, gearshift operation, etc.) in both EV and HEV modes. This also prevents the driver from experiencing any unpleasant sensations caused by differences in vehicle behavior between different control modes.

[0074] In this embodiment, the ECU 10 reduces the torque of the motor generator 3 by a larger amount in EV mode as the MG speed change rate increases.

[0075] With such a reduction, the torque of the motor generator 3 is reduced by a larger amount when the MG speed change rate increases in the EV mode, so that the EV mode and the HEV mode have essentially the same degree of acceleration / deceleration, thereby achieving smooth gear shifting.

[0076] Furthermore, the EV and HEV modes exhibit essentially the same degree of acceleration / deceleration at times other than gear changes, so the driver does not need to adjust the amount of accelerator input depending on the driving mode. For example, if the driver applies a certain amount of accelerator input, they will experience the same sensation of acceleration in both EV and HEV modes.

[0077] In a first modification of this embodiment, when the control mode is EV mode and when the manual clutch 8 is in the disengaged state or the manual transmission 4 is in neutral, the Fig. 1 ECU 10 shown the torque of the motor generator 3 based on the ratio of the moment of inertia on the side of the power source in HEV mode to the moment of inertia on the side of the power source in EV mode.

[0078] For example, the ECU 10 corrects the driver request torque by multiplying the driver request torque by the ratio of the moment of inertia on the side of the power source in EV mode (i.e., the moment of inertia of the motor generator 3) to the moment of inertia on the side of the power source in HEV mode (i.e., the moment of inertia of the motor generator 3 + the moment of inertia of the drive machine 2) and using the obtained value as the torque command value for the motor generator 3.

[0079] With this correction, when the manual clutch 8 is disengaged for gear changes in EV mode, the torque of the motor-generator 3 is corrected to a value corresponding to the moment of inertia, which is less than the torque generated by the main drive motor in response to the driver's request. Therefore, EV mode and HEV mode are caused to have essentially identical rates of change in the rotational speed of the motor-generator 3.

[0080] The processing of the motor torque control, which is carried out by a motor torque control device according to the first modification of this embodiment with the configuration mentioned above, is described with reference to Fig. 6 described. The processing for engine torque control described below is started with the start of the action of ECU 10 and is executed at predefined time intervals.

[0081] In step S11, the ECU receives 10 different sensor information from the hybrid vehicle 1. After executing the processing in step S11, the ECU 10 executes the processing in step S12.

[0082] In step S12, the ECU 10 calculates the driver request torque Tdr by interpolating the data in Fig. The mapping shown in step 2 is based on the accelerator opening degree and the MG speed. After processing in step S12, the ECU performs processing in step S13.

[0083] In step S13, ECU 10 determines whether the control mode of hybrid vehicle 1 is EV mode or not. If ECU 10 determines that the control mode of hybrid vehicle 1 is EV mode, it performs the processing in step S14. If ECU 10 determines that the control mode of hybrid vehicle 1 is not EV mode, it performs the processing in step S19.

[0084] In step S14, ECU 10 determines whether the manual clutch 8 is in the disengaged state or not. If ECU 10 determines that the manual clutch 8 is in the disengaged state, it performs the processing in step S16. If ECU 10 determines that the manual clutch 8 is not in the disengaged state, it performs the processing in step S15.

[0085] In step S15, ECU 10 determines whether manual transmission 4 is in neutral or not. If ECU 10 determines that manual transmission 4 is in neutral, it executes the operation in step S16. If ECU 10 determines that manual transmission 4 is not in neutral, it executes the processing in step S18.

[0086] In step S16, the ECU calculates the following as the MG torque correction coefficient: the moment of inertia of the motor generator 3 / (the moment of inertia of the motor generator 3 + the moment of inertia of the drive machine 2)

[0087] After the operation in step S16 has been carried out, the ECU 10 performs the processing in step S17.

[0088] In step S17, ECU 10 obtains the value by multiplying the driver request torque Tdr by the MG torque correction coefficient and uses the resulting value as the MG torque command value. After executing the processing in step S17, ECU 10 terminates the engine torque control processing.

[0089] In step S18, ECU 10 uses the driver request torque Tdr as the MG torque command value. After executing the processing in step S18, ECU 10 terminates the engine torque control processing.

[0090] In step S19, the ECU 10 calculates the MG torque command value according to the control in HEV mode. In HEV mode, the moment of inertia on the power source side, i.e., on the side of drive motor 2 of the manual clutch 8, corresponds to the moment of inertia of a normal internal combustion engine, so no control to correct the moment of inertia is executed. After executing the processing in step S19, the ECU 10 terminates the processing of the engine torque control.

[0091] As described above, in the first modification of this embodiment, the ECU 10 reduces the torque of the motor generator 3 based on the ratio of the moment of inertia on the side of the power source in HEV mode to the moment of inertia on the side of the power source in EV mode, when the control mode is EV mode and when the manual clutch 8 is in the disengaged state or the manual transmission 4 is in neutral.

[0092] Such a reduction means that the EV mode and the HEV mode essentially have the same MG speed change rate at the time of gear changes, and therefore the need for the driver to change the actuation of gear changes depending on the control mode can be eliminated.

[0093] Furthermore, the correction can be carried out without determining the actual action (speed) of the motor generator 3 immediately after the start of the gear change, thus enabling rapid correction.

[0094] In a second modification of this embodiment, when the control mode is HEV mode, the [missing information] increases Fig. ECU 10, as shown, controls the torque of the motor generator 3 based on a motor speed change rate. When the control mode is EV mode, the torque is reduced. Fig. 1 ECU 10 shown the torque of the motor generator 3 based on the MG speed change rate.

[0095] Due to the moment of inertia of the drive motor 2, the HEV mode exhibits moderate responsiveness in vehicle behavior. Therefore, when the motor speed change rate is moderate, the correction to increase responsiveness using the motor generator 3 is employed to enhance the vehicle's responsiveness to driver input.

[0096] The EV mode has a lower moment of inertia than the HEV mode and thus tends to have a more sensitive vehicle response. Therefore, the torque of motor generator 3 is adjusted to achieve a moderate response sensitivity.

[0097] Overall, the correction is implemented in such a way that the HEV mode and the EV mode essentially exhibit the same sensitivity in vehicle behavior.

[0098] In EV mode, for example, the ECU 10 subtracts the MG correction torque calculated using the following formula (2) from the driver request torque and uses the resulting value as the MG torque command value. MG correction torque=α×moment of inertia [kgm2] of the drive machine 2×MG speed change rate [rad / s2]

[0099] In HEV mode, for example, the ECU 10 adds the MG correction torque calculated using the following formula (3) to the MG torque command value for HEV mode and uses the resulting value as the torque command value for the motor generator 3. MG−correction torque=(1−α)×moment of inertia [kgm2] of the drive machine 2×MG−speed change rate [rad / s2]

[0100] In this formula, α denotes a numerical fit value between 0 and 1, obtained through experimentation or similar methods. A decrease in the value of α can cause an apparent decrease in the inertia of the drive motor.

[0101] A processing of an engine torque control, which is carried out by the engine torque control device according to the second modification of this embodiment with the configuration mentioned above, is described with reference to Fig. 7 described. The processing of the engine torque control described below is started with the beginning of the action of the ECU 10 and is executed at predefined time intervals.

[0102] In step S21, the ECU receives 10 different sensor information from the hybrid vehicle 1. After executing the processing in step S21, the ECU 10 executes the processing in step S22.

[0103] In step S22, the ECU 10 calculates the driver request torque Tdr by interpolating the data in Fig. The mapping shown in step 2 is based on the accelerator opening degree and the MG speed. After processing in step S22, the ECU performs processing in step S23.

[0104] In step S23, ECU 10 calculates the MG speed change rate, which is the amount of change in MG speed per unit of time. After executing the processing in step S23, ECU 10 executes the processing in step S24.

[0105] In step S24, ECU 10 determines whether the control mode of hybrid vehicle 1 is EV mode or not. If ECU 10 determines that the control mode of hybrid vehicle 1 is EV mode, it performs the processing in step S25. If ECU 10 determines that the control mode of hybrid vehicle 1 is not EV mode, it performs the processing in step S27.

[0106] In step S25, the ECU 10 calculates the MG correction torque in EV mode, which corresponds to the MG speed change rate, using the formula (2) mentioned above. After executing the processing in step S25, the ECU 10 executes the processing in step S26.

[0107] In step S26, ECU 10 subtracts the MG correction torque from the driver request torque Tdr and uses the resulting value as the MG torque command value. After completing the processing in step S26, ECU 10 terminates the engine torque control processing.

[0108] In step S27, the ECU 10 calculates the MG correction torque in HEV mode, which corresponds to the MG speed change rate, using the formula (3) mentioned above. After executing the processing in step S27, the ECU 10 executes the processing in step S28.

[0109] In step S28, the ECU 10 calculates the MG torque command value according to the control in HEV mode, adds the MG correction torque to the MG torque command value for HEV mode, and uses the resulting value as the MG torque command value. After executing the processing in step S28, the ECU 10 terminates the processing of the engine torque control.

[0110] As described above, in the second modification of this embodiment, when the control mode is HEV mode, the ECU 10 increases the torque of the motor generator 3 based on the MG speed change rate. When the control mode is EV mode, the ECU 10 reduces the torque of the motor generator 3 based on the MG speed change rate.

[0111] In such operation, the responsiveness of the hybrid vehicle 1 to the driver's input in HEV mode can be increased compared to conventional techniques, and the EV and HEV modes have essentially the same rate of change in engine speed. Therefore, it is unnecessary for the driver to change the extent of input between EV and HEV modes, and thus any discomfort experienced by the driver due to the vehicle's behavior can be prevented.

[0112] In a third modification of this embodiment, the Fig. 1 ECU 10 shown, when the manual clutch 8 is disengaged or the manual transmission 4 is in neutral and when the control mode is HEV mode, the torque of the motor generator 3 is based on the ratio of the moment of inertia on the side of the power source in HEV mode to the moment of inertia on the side of the power source in EV mode. When the manual clutch 8 is disengaged or the manual transmission 4 is in neutral and when the control mode is EV mode, the in Fig. 1 ECU 10 shown the torque of the motor generator 3 based on the ratio of the moment of inertia on the side of the power source in HEV mode to the moment of inertia on the side of the power source in EV mode.

[0113] In EV mode, for example, the ECU 10 obtains the value by multiplying the driver request torque by the MG torque correction coefficient calculated according to the following formula (4) and uses the obtained value as the MG torque command value. MG−Torque correction coefficient=Moment of inertia of the motor generator 3 / {(Moment of inertia of the motor generator 3+Moment of inertia of the drive machine 2)×α}

[0114] In HEV mode, for example, the ECU 10 obtains the value by multiplying the driver request torque by the MG torque correction coefficient calculated using the following formula (5) and uses the obtained value as the MG torque command value. MG−Torque correction coefficient={(moment of inertia of the motor generator 3+moment of inertia of the drive machine2)×(1−α)} / (moment of inertia of the motor generator 3−1)

[0115] In this formula, α denotes a numerical adjustment value between 0 and 1, obtained through experiments or similar methods. A reduction in the value of α can lead to an apparent reduction in the moment of inertia of the drive motor.

[0116] In HEV mode, when the manual clutch 8 is in the disengaged state or the manual transmission 4 is in the neutral state, a torque command value for the drive motor 2 is controlled by the driver request torque.

[0117] A processing of the motor torque control, which is carried out by the motor torque control device according to the third modification of this embodiment with the configuration mentioned above, is described with reference to Fig. 8 described. The processing described below for engine torque control is started with the start of the action of the ECU 10 and is executed at predefined time intervals.

[0118] In step S31, the ECU receives 10 different sensor information from the hybrid vehicle 1. After executing the processing in step S31, the ECU 10 executes the processing in step S32.

[0119] In step S32, the ECU 10 calculates the driver request torque Tdr by interpolating the data in Fig. The mapping shown in step 2 is based on the accelerator opening degree and the MG speed. After processing in step S32, the ECU performs processing in step S33.

[0120] In step S33, ECU 10 determines whether the manual clutch 8 is in the disengaged state or not. If ECU 10 determines that the manual clutch 8 is in the disengaged state, it performs the processing in step S35. If ECU 10 determines that the manual clutch 8 is not in the disengaged state, it performs the processing in step S34.

[0121] In step S34, ECU 10 determines whether manual transmission 4 is in neutral or not. If ECU 10 determines that manual transmission 4 is in neutral, it executes the operation in step S35. If ECU 10 determines that manual transmission 4 is not in neutral, it executes the operation in step S39.

[0122] In step S35, ECU 10 determines whether the control mode of hybrid vehicle 1 is EV mode or not. If ECU 10 determines that the control mode of hybrid vehicle 1 is EV mode, it performs the processing in step S36. If ECU 10 determines that the control mode of hybrid vehicle 1 is not EV mode, it performs the processing in step S37.

[0123] In step S36, the ECU 10 calculates the MG torque correction coefficient in EV mode using the aforementioned formula (4) based on the ratio of the moment of inertia on the side of the power source in HEV mode to the moment of inertia on the side of the power source in EV mode. After completing the processing in step S36, the ECU 10 performs the processing in step S38.

[0124] In step S37, the ECU 10 calculates the MG torque correction coefficient in HEV mode using the aforementioned formula (5) based on the ratio of the moment of inertia on the side of the power source in HEV mode to the moment of inertia on the side of the power source in EV mode. After completing the processing in step S37, the ECU 10 performs the processing in step S38.

[0125] In step S38, ECU 10 obtains the value by multiplying the driver request torque Tdr by the MG torque correction coefficient and uses the resulting value as the MG torque command value. After executing the processing in step S38, ECU 10 terminates the engine torque control processing.

[0126] In step S39, ECU 10 determines whether the control mode of hybrid vehicle 1 is EV mode or not. If ECU 10 determines that the control mode of hybrid vehicle 1 is EV mode, it performs the processing in step S40. If ECU 10 determines that the control mode of hybrid vehicle 1 is not EV mode, it performs the processing in step S41.

[0127] In step S40, ECU 10 uses the driver request torque Tdr as the MG torque command value. After executing the operation in step S40, ECU 10 terminates the engine torque control processing.

[0128] In step S41, the ECU 10 calculates the MG torque command value according to the control in HEV mode. After executing the processing in step S41, the ECU 10 terminates the processing of the engine torque control.

[0129] As described above, in the third modification of this embodiment, the ECU 10 increases the torque of the motor-generator 3 based on the ratio of the moment of inertia on the side of the power source in HEV mode to the moment of inertia on the side of the power source in EV mode, when the manual clutch 8 is disengaged or the manual transmission 4 is in neutral, and when the control mode is HEV mode. When the manual clutch 8 is disengaged or the manual transmission 4 is in neutral, and when the control mode is EV mode, the ECU 10 reduces the torque of the motor-generator 3 based on the ratio of the moment of inertia on the side of the power source in HEV mode to the moment of inertia on the side of the power source in EV mode.

[0130] Such a reduction means that the EV mode and the HEV mode essentially have the same MG speed change rate at the time of gear changes, and therefore the need for the driver to change the actuation of gear changes depending on the control mode can be eliminated.

[0131] Furthermore, the correction can be performed without determining the actual action (speed) of the motor generator 3 immediately after the start of the gear change, and thus a rapid correction can be achieved.

[0132] In this embodiment, an example has been described in which the ECU 10 performs various determinations or calculations based on different sensor information. However, the configuration is not limited to the example mentioned above. It can be configured such that the hybrid vehicle 1 includes a communication unit that can communicate with an external device, for example, an external server; various determinations or calculations are performed by the external device based on information acquired from different sensors and transmitted by the communication unit; the communication unit receives the determination or calculation result; and various control actions are performed using the received determination or calculation result.

[0133] Although the embodiment of the present invention has been disclosed above, it is obvious that modifications can be applied by those skilled in the art without departing from the scope of the present invention. It is intended that all such modifications and equivalents are included in the claims. [List of reference symbols] 1 hybrid vehicle 2 Drive machine 3 Motor generator 4 manual transmission (gearbox) 7 automatic clutch 8 manual clutch 10 ECU (control unit) 42 Neutral switch 81 Clutch pedal sensor 91 Accelerator Opening Sensor

Claims

[1] An engine torque control device for a hybrid vehicle (1) in which a drive machine (2) and a motor generator (3) are connected to each other via an automatic clutch (7) and the motor generator (3) and a transmission (4) are connected to each other via a manual clutch (8), wherein a control mode of the hybrid vehicle (1) comprises an EV mode in which the automatic clutch (7) is disengaged to cause the hybrid vehicle (1) to be driven by power from the motor generator (3) and an HEV mode in which the automatic clutch (7) is engaged to cause the hybrid vehicle (1) to be driven by power from the drive machine (2) or by power from the drive machine (2) and the motor generator (3), wherein the engine torque control device has a control unit (10) configured to switch between EV mode and HEV mode based on a driver request torque calculated based on at least one accelerator opening degree, wherein the control unit (10) corrects a torque of the motor generator (3) such that a rate of change of speed of the motor generator (3) in the EV mode and a rate of change of speed of the motor generator (3) in the HEV mode are within a range. [2] The motor torque control device for a hybrid vehicle (1) according to claim 1, wherein the control unit (10) reduces the torque of the motor generator (3) in EV mode by a larger amount when the rate of change of the rotational speed of the motor generator (3) increases. [3] The engine torque control device for a hybrid vehicle (1) according to claim 1 or claim 2, wherein the control unit (10) reduces the torque of the motor generator (3) based on a ratio of a moment of inertia on one side of a power source in the HEV mode to a moment of inertia on one side of a power source in the EV mode, when the hybrid vehicle (1) is in EV mode and when the manual clutch (8) is in a disengaged state or the transmission (4) is in a neutral state. [4] The engine torque control device for a hybrid vehicle (1) according to any one of claims 1 to 3, wherein the control unit (10) increases the torque of the motor generator (3) based on a ratio of a moment of inertia on one side of a power source in the HEV mode to a moment of inertia on one side of a power source in the EV mode, when the hybrid vehicle (1) is in the HEV mode and when the manual clutch (8) is in a disengaged state or the transmission (4) is in a neutral state. [5] The engine torque control device for a hybrid vehicle (1) according to any one of claims 1 to 4, wherein the control unit (10) increases the torque of the motor generator (3) in HEV mode based on the rate of change of the speed of the motor generator (3), and the control unit (10) reduces the torque of the motor generator (3) in EV mode based on the rate of change of the speed of the motor generator (3).

Images