Vehicle control device

Abstract

Vehicle control device (10) comprising an internal combustion engine (11) and an electric motor, wherein the device (10) comprises: a clutch (17) which is arranged in a power transmission path (40) which couples the internal combustion engine (11) and the drive wheels (22); a first driving control device that performs an electric motor drive in which the drive wheels (22) are driven by the electric motor in a state in which the clutch (17) is disengaged to decouple the internal combustion engine (11) from the drive wheels (22) and the internal combustion engine (11) is stopped; a second driving control device that performs a co-rotating drive in which the clutch (17) is engaged, while fuel injection of the internal combustion engine (11) is stopped in a state in which the electric motor drive is performed, and the internal combustion engine (11) is rotated during the drive; an electric motor control device that increases an output torque (Tm1) of the electric motor when the driving mode switches from electric motor driving to pedal-assisted driving; and a transmission mechanism (16) arranged in the power transmission path (40) that couples the internal combustion engine (11) and the drive wheels (22); characterized by a transmission control device (72) that reduces a gear ratio of the transmission mechanism (16) when the driving mode switches from electric motor driving to co-rotating driving, wherein the gear ratio is a ratio of the input shaft speed to the output shaft speed of the transmission mechanism (16).

Description

CROSS-REFERENCE TO RELATED REGISTRATIONS

[0001] The present application claims priority from Japanese patent application No. 2015-122538, filed on June 18, 2015, the entire contents of which are hereby incorporated by reference. BACKGROUND 1. Technical field

[0002] The present invention relates to a vehicle control device comprising an internal combustion engine and an electric motor. 2. Related technology

[0003] To reduce the fuel consumption of an internal combustion engine, a vehicle has been proposed in which a clutch located between the internal combustion engine and the drive wheels is disengaged to stop the internal combustion engine while driving (see WO 2014 / 068 719 A1). The vehicle disclosed in WO 2014 / 068 719 A1 performs a fuel cut-off when the internal combustion engine is stopped, with the fuel supply being cut off while the clutch is engaged.

[0004] Although cylinder deactivation reduces pumping losses in the combustion engine of vehicle WO 2014 / 068 719 A1, the fuel supply to the combustion engine is stopped while the clutch is engaged. If, as described above, only the fuel supply to the combustion engine is stopped for the purpose of reducing its fuel consumption, this leads to excessive deceleration of the vehicle.

[0005] WO 2014 / 068 719 A1 discloses a vehicle driving controller that can both improve the vehicle's fuel economy during coasting and ensure the availability of negative brake pressure when braking is required. The vehicle speed threshold for downshifting from coasting to normal driving is set lower than the threshold for downshifting from coasting to normal driving. Therefore, if the vehicle speed is higher than the former threshold, at which negative brake pressure is more likely to be needed, the vehicle is in neutral, i.e., the engine is running, so that when braking is required, the engine is running and negative brake pressure is available.If the vehicle speed is less than or equal to the vehicle speed threshold and less negative brake pressure is required, the aforementioned coasting driving with the engine off can be performed, which allows for fuel-efficient driving.

[0006] US 2011 / 0 165 992 A1 discloses a hybrid vehicle in which a clutch is arranged between an internal combustion engine and a motor / generator. The hybrid vehicle is controlled to suppress frequent engagement / disengagement of the clutch during idling with the internal combustion engine coasting. A clutch control unit manages the clutch and selects one of the following driving modes: 1) an EV drive mode, in which the vehicle travels solely by the motive power of the motor / generator with the clutch disengaged; 2) an HEV drive mode, in which the vehicle travels by the motive power of the engine and / or the motor / generator with the clutch engaged; and 3) an engine braking drive mode, in which the vehicle travels in neutral or by the motive power of the motor / generator while braking the engine, with the clutch engaging and fuel supply being stopped when the battery charge is greater than or equal to a threshold.

[0007] DE 10 2006 027 387 A1 discloses a braking system for a hybrid motor vehicle in which the crankshaft of the internal combustion engine is temporarily driven during purely electric driving operation by means of at least one electric motor to generate a vacuum in the intake manifold in order to supply the vacuum chamber of its brake booster with vacuum from the additional vacuum reservoir only when, during or after one or more actuations of the brake pedal, the vacuum in the vacuum reservoir of the brake booster falls to a predefinable lower limit or falls below the lower limit.

[0008] US 2011 / 0 174 559 A1 discloses a hybrid vehicle in which a clutch is arranged between an internal combustion engine and a motor / generator, and the disengagement of the clutch during idling while the internal combustion engine is towing is controlled. A drive control unit engages the clutch so that the vehicle coasts to a stop in neutral, while the engine is braked during the deceleration. When the hybrid vehicle's transmission downshifts while in neutral, the clutch is disengaged during the downshift. SUMMARY OF THE INVENTION

[0009] It is desirable to suppress excessive deceleration of a vehicle.

[0010] One aspect of the present invention provides for a A vehicle control device comprising an internal combustion engine and an electric motor, comprising: a clutch arranged in a power transmission path that couples the internal combustion engine and the drive wheels; a first driving control device that performs electric motor driving, wherein the drive wheels are driven by the electric motor in a state in which the clutch is disengaged to decouple the internal combustion engine from the drive wheels, and the internal combustion engine is stopped; a second driving control device that performs a rotary driving mode in which the clutch is engaged, while fuel injection of the internal combustion engine is stopped in a state in which electric motor driving is performed, and the internal combustion engine is rotated during driving; an electric motor control device that increases an output torque of the electric motor when the driving mode switches from electric motor driving to rotary driving;and a transmission mechanism located in the power transmission path that couples the internal combustion engine and the drive wheels; characterized by a transmission control device that reduces a gear ratio of the transmission mechanism when the driving mode switches from electric motor driving to rotary driving, wherein the gear ratio is a ratio of the input shaft speed to the output shaft speed of the transmission mechanism.

[0011] In one embodiment, the electric motor control unit can calculate a target torque of the electric motor based on the output torque of the electric motor and a torque capacity of the clutch, and The second drive control device can allow the lateral movement if the target torque falls below a predetermined value, and can prevent the lateral movement if the target torque exceeds the predetermined value.

[0012] In one embodiment, the vehicle control device may further include a vacuum amplifier that is coupled to an intake manifold of the internal combustion engine.

[0013] In one embodiment, the vehicle control device may further include a compressor that is coupled to a crankshaft of the internal combustion engine. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a schematic diagram representing a vehicle control device according to an example of the present invention; Fig. 2A to 2C are schematic diagrams that represent an example of driving modes provided in the vehicle control device; Fig. Figure 3 is a schematic diagram representing peripheral equipment coupled to an internal combustion engine; Fig. Figure 4 is a flowchart that illustrates an example of an internal combustion engine rotation process; Fig. Figure 5 is a flowchart that illustrates an example of an internal combustion engine rotation determination to be carried out in the internal combustion engine rotation process; Fig. Figure 6 is a flowchart that illustrates an example of a limit torque determination to be carried out in the internal combustion engine rotation process; Fig. Figure 7 is a flowchart that illustrates an example of a driving status determination to be performed in the internal combustion engine rotation process; and Fig. Figure 8 is a time diagram that illustrates an example of a switching procedure from engine driving to co-rotating driving. DETAILED DESCRIPTION

[0014] An example of the present invention is described in detail below with reference to the accompanying drawings. Fig. Figure 1 is a schematic diagram representing a vehicle control device 10 according to an example of the present invention. As shown in Fig. As shown in Figure 1, the vehicle control device 10 includes a drive unit 13 equipped with an internal combustion engine 11 and a motor-generator (electric motor) 12. The drive unit 13 includes a continuously variable transmission (gearbox mechanism) 16 with a primary pulley 14 and a secondary pulley 15. One side of the primary pulley 14 is coupled to the internal combustion engine 11 by an internal combustion engine clutch 17 and a torque converter 18. The other side of the primary pulley 14 is coupled to a rotor 19 of the motor-generator 12. The secondary pulley 15 is coupled to drive wheels 22 by a drive wheel output shaft 20 and a differential mechanism 21. [Torque converter]

[0015] The torque converter 18 includes a pump impeller 32, which is coupled to a crankshaft 30 by a front cover 31, and a turbine rotor 34, which faces the pump impeller 32 and is coupled to a turbine shaft 33. The torque converter 18 includes a lock-up clutch 36 with a clutch plate 35. The interior of the torque converter 18 is divided, with the clutch plate 35 as the boundary, into a working chamber 37 and a separation chamber 38. Increasing the hydraulic pressure in the working chamber 37 reduces the hydraulic pressure in the separation chamber 38, thereby pressing the clutch plate 35 against the front cover 31 and switching the lock-up clutch 36 to the engaged state.On the other hand, the hydraulic pressure in the working chamber 37 is reduced by increasing the hydraulic pressure in the separating chamber 38, which separates the clutch plate 35 from the front cover 31 and switches the bypass clutch 36 into a disengaged state. [Continuously variable transmission]

[0016] The continuously variable transmission 16 is arranged in a power transmission path 40, which couples the internal combustion engine 11 to the drive wheels 22. The continuously variable transmission 16 includes the primary pulley 14, which is provided on a primary shaft 41, and the secondary pulley 15, which is provided on a secondary shaft 42. A drive chain 43 wraps around the primary pulley 14 and the secondary pulley 15 and transmits the power between the pulleys 14 and 15. A primary chamber 44 is provided in the primary pulley 14 and adjusts the pulley groove width. A secondary chamber 45 is provided in the secondary pulley 15 and adjusts the pulley groove width. The hydraulic pressure supplied to the secondary chamber 45 is controlled such that a clamping force of the drive chain 43 by the secondary pulley 15 is set, and a torque capacity of the continuously variable transmission is set.Furthermore, the hydraulic pressures supplied to the primary chamber 44 and the secondary chamber 45 are controlled to change the wrap diameter of the drive chain 43 while the pulley groove width is changed. The power transmission path 40, which couples the internal combustion engine 11 to the drive wheels 22, includes the torque converter 18, the turbine shaft 33, the primary shaft 41, the secondary shaft 42, the drive wheel output shaft 20, and the differential mechanism 21. [Internal combustion engine clutch]

[0017] The internal combustion engine clutch (clutch) 17 is located between the torque converter 18 and the primary pulley 14. In other words, the internal combustion engine clutch 17, for switching between the engaged and disengaged states, is located in the power transmission path 40, which couples the internal combustion engine 11 to the drive wheels 22. The internal combustion engine clutch 17 includes a clutch plate 50, which is coupled to the turbine shaft 33, and a clutch plate 51, which is coupled to the primary shaft 41. The internal combustion engine clutch 17 includes a hydraulic actuator 52, to which hydraulic oil is supplied. As the hydraulic pressure in the hydraulic actuator 52 increases, the clutch plates 50 and 51 engage, and the internal combustion engine clutch 17 is switched to the engaged state.On the other hand, as the hydraulic pressure in the hydraulic actuator 52 decreases, the engaged state of the clutch plates 50 and 51 is released, and the internal combustion engine clutch 17 is switched to the disengaged state. [Safety coupling]

[0018] A safety clutch 55 is provided between the secondary pulley 15 and the drive wheels 22 and can set a holding force, in other words, a torque capacity. The safety clutch 55 includes a clutch plate 56, which is coupled to the secondary shaft 42, and a clutch plate 57, which is coupled to the drive wheel output shaft 20. The safety clutch 55 includes a hydraulic actuator 58, to which hydraulic oil is supplied. As the hydraulic pressure in the hydraulic actuator 58 increases, the clutch plates 56 and 57 engage with each other, and the safety clutch 55 is switched to the engaged state. Conversely, as the hydraulic pressure in the hydraulic actuator 58 decreases, the clutch plates 56 and 57 disengage, and the safety clutch 55 switches to the disengaged state.The torque capacity of the safety clutch 55 is controlled to be lower than the torque capacity of the continuously variable transmission 16. In this configuration, if a large torque is applied to the continuously variable transmission 16, the safety clutch 55 can slip in front of the continuously variable transmission 16, thereby protecting the continuously variable transmission 16. [Hydraulic control system]

[0019] To supply the hydraulic oil to the torque converter 18, the continuously variable transmission 16, the combustion engine clutch 17, and the safety clutch 55, an oil pump 60 is provided in the drive unit 13 and is driven by the combustion engine 16 or the primary shaft 41. The oil pump 60 is coupled to a pump housing 63 of the torque converter 18 by a chain mechanism 62, which has a one-way clutch 61. The oil pump 60 is coupled to the primary shaft 61 by a chain mechanism 65, which has a one-way clutch 64.

[0020] When the pump housing 63 rotates faster than the primary shaft 41, a driving force is transmitted from the pump housing 63 to the oil pump 60 via the chain mechanism 62. In other words, when the internal combustion engine 11 is running, the oil pump 60 is driven by the power of the internal combustion engine 11. Conversely, when the pump housing 63 rotates slower than the primary shaft 41, the driving force is transmitted from the primary shaft 41 to the oil pump 60 via the chain mechanism 65. In other words, even when the internal combustion engine 11 is stopped, as in the electric motor operation described later, the oil pump 60 is driven by the primary shaft 41 during forward motion.

[0021] Furthermore, to control the hydraulic oil supplied by the oil pump 60, a valve body 66 is provided in the drive unit 13, containing several solenoid valves and oil channels. The hydraulic oil supplied by the oil pump 60 is fed through the valve body 66 to the torque converter 18, the continuously variable transmission 16, the combustion engine clutch 17, and the safety clutch 55. Incidentally, to ensure control hydraulic pressure even during slow-speed driving with the combustion engine stopped or during reverse driving with the combustion engine stopped, an electric oil pump (not shown) is provided in the drive unit 13, in addition to the oil pump 60. [Electronic control system]

[0022] To control the operating state of the drive unit 13, the vehicle control device 10 includes several control units 70 to 72. Among these control units, the internal combustion engine control unit 70 is provided for controlling the internal combustion engine 11, and the hybrid control unit 71 is provided for controlling the motor-generator 12. Additionally, the transmission control unit 72 is provided for controlling the continuously variable transmission 60, the engine clutch 17, the lock-up clutch 36, and the safety clutch 55. The internal combustion engine control unit 70 outputs control signals to a throttle valve and an injector and controls the operating state of the internal combustion engine 11. The hybrid control unit 71 outputs control signals to an inverter 73 and a converter 74 and controls the operating state of the motor-generator 12.Furthermore, the transmission control unit 72 outputs a control signal to the valve body 66 and controls operating states of the continuously variable transmission 16, the internal combustion engine clutch 17, the lock-up clutch 36 and the safety clutch 55.

[0023] Each of these control units 70 to 72 contains a microcomputer with a CPU, ROM, and RAM, as well as a driver circuit unit that generates control currents for various actuators. The respective control units 70 to 72 are interconnected via a vehicle-specific network 75, such as CAN. The vehicle-specific network 75 is connected to an accelerator pedal sensor 76, which detects the operating state of the accelerator pedal; a brake sensor 77, which detects the operating state of the brake pedal; a vehicle speed sensor 78, which detects the vehicle speed; and a camera unit 79, which images the vehicle's surroundings. As described above, various pieces of information indicating the vehicle's driving status and driving environment are transmitted via the vehicle-specific network 75. [Driving mode]

[0024] The Fig. Figures 2A to 2C are schematic diagrams illustrating examples of driving modes provided in the vehicle control device 10. In each of the Fig. 2A to 2C is an example of a power transmission status in each driving mode, indicated by hollow arrows. As in the Fig. As shown in Figures 2A to 2C, the vehicle control device 10 includes the following driving modes: an electric motor driving mode, a parallel driving mode, and a co-rotating driving mode. The electric motor driving mode is a driving mode for performing electric motor driving in which the drive wheels 22 are driven by the motor-generator 12, and the parallel mode is a driving mode for performing parallel driving in which the drive wheels 22 are driven by the internal combustion engine 11 and the motor-generator 12. The co-rotating driving mode is a driving mode for performing co-rotating driving in which the internal combustion engine clutch 17 is engaged to rotate the internal combustion engine 11 while maintaining a fuel lock or fuel cut-off of the internal combustion engine 11.

[0025] If, as in Fig. As shown in Figure 2A, when the electric motor driving mode is executed, the combustion engine clutch 17 is controlled to remain in the disengaged state, and the combustion engine 11 is decoupled from the drive wheels 22. With this configuration, the drive wheels 22 can be driven by the motor generator 12 in a state where the combustion engine 11 is stopped. If, as shown in Figure 2A, the electric motor driving mode is executed, the combustion engine clutch 17 is controlled to remain in the disengaged state, and the combustion engine 11 is decoupled from the drive wheels 22. Fig. As shown in Figure 2B, when parallel driving mode is executed, the combustion engine clutch 17 is controlled so that it remains engaged, and the combustion engine 11 is coupled to the drive wheels 22. With this configuration, the drive wheels 22 are not only driven by the motor-generator 12, but can also be driven by the combustion engine 11. Furthermore, if, as in Fig. As shown in Figure 2C, when the co-rotating drive mode is executed, the combustion engine clutch 17 is switched from the disengaged state to the engaged state, while the fuel lock of the combustion engine 11 is maintained during electric motor operation. With this configuration, the combustion engine 11 can be rotated during driving while fuel injection from the combustion engine 11 remains stopped; in other words, fuel injection from an injector (not shown) remains stopped.

[0026] Each of the electric motor driving modes – parallel driving mode and rotary driving mode, as described above – is set based on a vehicle status, such as vehicle speed or accelerator pedal position. For example, at low speeds or with a low accelerator pedal position, the electric motor driving mode is set as the driving mode, whereas at high speeds or with a high accelerator pedal position, the parallel driving mode is set as the driving mode. If, in electric motor driving mode with the combustion engine stopped, rotation of the combustion engine is required due to a lack of vacuum from a vacuum booster 83 (to be described later), the rotary driving mode is set by engaging the combustion engine clutch 17 while the fuel supply to the combustion engine 11 remains stopped, and rotating the combustion engine 11.By executing the co-rotating driving mode, the internal combustion engine 11 can be rotated while the fuel injection remains stopped, and the fuel consumption of the internal combustion engine 11 can be reduced.

[0027] The switching of the driving mode is controlled by the various control units 70 to 72 described above. In other words, in one embodiment, the combustion engine control unit 70, the hybrid control unit 71, and the transmission control unit 72 function as the first driving control unit, which executes the electric motor drive, and also function as the second driving control unit, which executes the co-rotating drive. In one embodiment, the hybrid control unit 71 functions as the electric motor control unit, which controls the motor generator 12. In another embodiment, the transmission control unit 72 functions as the transmission control unit, which controls the continuously variable transmission 16. [Internal combustion engine peripheral equipment]

[0028] As described above, the co-rotating driving mode is executed based on the lack of vacuum in the vacuum booster 83. Fig. Figure 3 is a schematic diagram representing peripheral equipment coupled to the internal combustion engine 11. As shown in Fig. As shown in Figure 3, the vacuum booster 83 is located between a brake pedal 11 and a master cylinder 82, which configure a brake device 18, and increases the brake actuation force. The vacuum booster 83 is divided into a vacuum chamber 85 and an atmospheric pressure chamber 86, with a drive piston 84 as the boundary. The vacuum chamber 85 of the vacuum booster 83 is coupled to an intake pipe 88 of the internal combustion engine 11 by a vacuum pipe 87. The atmospheric pressure chamber 86 of the vacuum booster 83 is coupled to a supply and discharge pipe 89, and the supply and discharge pipe 89 is coupled to an open pipe 91 and the vacuum pipe 87 by a control valve 90.

[0029] When the driver presses the brake pedal 81, atmospheric pressure is introduced from the open tube 91 and the supply and discharge tube 89 into the atmospheric pressure chamber 86 of the vacuum booster 83 because the open tube 91 and the supply and discharge tube 89 are connected via the control valve 90. Because the drive piston 84 is biased due to a pressure differential between the vacuum chamber 85 and the atmospheric pressure chamber 86, the driver's brake application is assisted by the drive piston 84. Conversely, when the driver releases the pressure on the brake pedal 81, the pressure differential between the vacuum chamber 85 and the atmospheric pressure chamber 86 is eliminated because the vacuum tube 87 and the supply and discharge tube 89 are connected via the control valve 90. In this configuration, the piston 84 is pushed back by a return spring 92.

[0030] As described above, each time the pressure of the brake pedal 81 is released, air flows from the atmospheric pressure chamber 86 into the vacuum chamber 85 of the vacuum booster 83. Therefore, during electric motor operation, in which the internal combustion engine 11 is stopped, the booster vacuum in the vacuum chamber 85 decreases each time the brake is applied. In other words, during electric motor operation, the pressure in the vacuum chamber 85 increases each time the brake is applied. Since the decrease in the booster vacuum in the vacuum chamber 83, as described above, results in a decrease in the braking force, it is necessary to rotate the internal combustion engine 11 during the regenerative driving process to maintain the booster vacuum in the vacuum booster 83.

[0031] Without limiting ourselves to the vacuum booster 83 described above, a compressor 94 of an air conditioning system 93, for example, is considered peripheral equipment that requires the rotation of the internal combustion engine. As in Fig. As shown in Figure 3, the crankshaft 30 of the internal combustion engine 11 is coupled to the compressor 94 by a pulley mechanism 95. The compressor 94 is driven to compress refrigerant gas, allowing a coolant to circulate in a cooling circuit (not shown) and cool the vehicle interior using the air conditioning system 93. In other words, during electric motor operation, when the internal combustion engine 11 is stopped (because the compressor 94 driven by the internal combustion engine 11 is also stopped), it is assumed that the vehicle interior temperature rises relative to the set temperature of the air conditioning system 93. If the vehicle interior temperature rises relative to the set temperature, as described above, it is necessary to rotate the internal combustion engine 11 by driving the compressor 94 and thus lowering the vehicle interior temperature. [Excerpt of the flowchart]

[0032] Now a procedure is described for when the combustion engine is to rotate due to a decrease in the booster vacuum, in other words, a process for carrying out a combustion engine rotation process during electric motor operation. Fig. Figure 4 is a flowchart that illustrates an example of the internal combustion engine rotation process; Fig. Figure 5 is a flowchart that illustrates an example of an internal combustion engine rotation determination to be carried out in the internal combustion engine rotation process; Fig. Figure 6 is a flowchart that illustrates an example of a limit torque determination to be carried out in the internal combustion engine rotation process; Fig. Figure 7 is a flowchart illustrating an example of a driving status determination to be performed during the internal combustion engine rotation process. The following description details the internal combustion engine rotation process during electric motor operation, following descriptions of an internal combustion engine rotation determination, a limit torque determination, and a driving status determination. The internal combustion engine rotation process, the internal combustion engine rotation determination, the limit torque determination, and the driving status determination are performed by the internal combustion engine control unit 70, the hybrid control unit 71, and the transmission control unit 72. [Internal combustion engine rotation determination]

[0033] As in Fig. As shown in Figure 5, in step S101 an amplifier vacuum P1 is detected in the vacuum amplifier 83. In the subsequent step S102, it is determined whether the amplifier vacuum P1 falls below a predetermined value Px or not. If in step S102 it is determined that the amplifier vacuum P1 falls below the predetermined value Px, in other words, if it is determined that the amplifier vacuum P1 is insufficient, the process proceeds to step S103, because the amplifier vacuum P1 must be ensured, and it is determined that the rotation of the internal combustion engine 11 is required. The amplifier vacuum P1 is a value obtained by subtracting the pressure in the vacuum chamber 85 from atmospheric pressure. The amplifier vacuum P1 decreases as the pressure in the vacuum chamber 85 increases and approaches atmospheric pressure.The amplifier vacuum P1 increases when the pressure in the vacuum chamber 85 decreases and moves away from atmospheric pressure.

[0034] If step S102 determines that the booster vacuum P1 exceeds the predetermined value Px—in other words, if it is determined that the booster vacuum P1 is ensured—the process proceeds to step S104, which determines whether the air conditioning system 93 is operational (i.e., switched on). If step S104 determines that the air conditioning system 93 is operational, the process proceeds to step S105, where a cooling temperature difference T1 is calculated by subtracting the set temperature from the current vehicle interior temperature. The process then proceeds to step S106, which determines whether the cooling temperature difference T1 exceeds a predetermined value Tx. If step S106 determines that the cooling temperature difference T1 exceeds the predetermined value Tx,, if it is determined that the vehicle interior temperature is rising, because compressor 94 needs to be driven and the vehicle interior temperature needs to be lowered, the process continues to step S103, and it is determined that the rotation of the internal combustion engine 11 is required.

[0035] If in step S104 it is determined that the air conditioning 93 is in the stopped state, i.e., the air conditioning is switched off, or if in step S106 it is determined that the cooling temperature difference T1 is equal to or less than the predetermined value Tx, the process continues to step S107, and a driver-requested deceleration G1 is calculated based on the pressure of the brake pedal 81. For example, the requested deceleration G1 is set higher if the pressure on the brake pedal 81 is greater, whereas the requested deceleration G1 is set lower if the pressure on the brake pedal 81 is less. Furthermore, the process continues to step S108, and an electric motor deceleration Gx, obtained through regenerative braking of the motor-generator 12, is calculated based on the state of charge (SOC) of a battery 96.For example, if the state of charge (SOC) decreases, the electric motor deceleration Gx is increased because sufficient regenerative braking can be performed. Conversely, if the state of charge (SOC) is higher, the electric motor deceleration Gx is decreased because sufficient regenerative braking becomes difficult. The process then proceeds to step S109, where it is determined whether the requested deceleration G1 exceeds the electric motor deceleration Gx. If step S109 determines that the requested deceleration G1 exceeds the electric motor deceleration Gx, achieving sufficient deceleration becomes challenging. Therefore, to facilitate the combined use of the combustion engine braking, the process continues to step S103, where it is determined that rotation of the combustion engine 11 is required.If, on the other hand, it is determined in step S109 that the requested delay G1 falls below the electric motor delay Gx, the process continues to step S110, and it is determined that the rotation of the internal combustion engine 11 is not required. [Limit torque determination]

[0036] As in Fig. As shown in Figure 6, in step S101 an output torque Tm1 is calculated, which is currently being output by the motor-generator 12, and in the subsequent step S202 a synchronized torque Tc1, which is generated during synchronized operation, is estimated. In this description, the synchronized torque Tc1 represents a load torque of the internal combustion engine 11 acting on the motor-generator 12 and the drive wheels 12 when the internal combustion engine clutch 17 is engaged to rotate the internal combustion engine 11. Because the synchronized torque Tc1 is not transmitted beyond the torque capacity of the internal combustion engine clutch 17, the torque capacity of the internal combustion engine clutch 17 is used as the synchronized torque Tc1.Although the torque capacity of the combustion engine clutch 17 is stored in the transmission control unit 72, the torque capacity can also be calculated based on the hydraulic pressure of the combustion engine clutch 17 without using data from the stored torque capacity. If, in step S201 described above, the output torque Tm1 is output to the drive side, the output torque Tm1 is calculated as a positive value, and if the output torque Tm1 is output to the regenerative side, the output torque Tm1 is calculated as a negative value.

[0037] Then, in step S203, a target torque Tm2 of the motor-generator 12 is calculated by adding the output torque Tm1 and the synchronous torque Tc1. In other words, the target torque Tm2 of the motor-generator 12 is calculated by adding the output torque Tm1 of the motor-generator 12 and the torque capacity of the internal combustion engine clutch 17. The process then proceeds to step S204, where it is calculated whether the target torque Tm2 falls below a predetermined value Tmx. If step S204 determines that the target torque Tm2 falls below the predetermined value Tmx, and because the target torque Tm2 can be output by the motor-generator 12, the process continues to step S205, where it is determined that the output torque for performing the synchronous driving, i.e., the electric motor torque, has a limit.On the other hand, if in step S204 it is determined that the target torque Tm2 is equal to or greater than the predetermined value Tmx, because it is difficult to output the target torque Tm2 from the motor generator 12, the process continues to step S206, and it is determined that the output torque for carrying out the co-rotating drive, i.e. the electric motor torque, has no limit. [Driving status determination]

[0038] As in Fig. As shown in Figure 7, in step S301, based on a detection signal from a longitudinal acceleration sensor, it is determined whether a predetermined downward slope continues for a predetermined time or not. If step S301 determines that the downward slope continues, the process proceeds to step S302, and it is determined that the vehicle's driving state is in a non-acceleration state, where the vehicle does not suddenly accelerate. Conversely, if step S301 determines that the downward slope does not continue, the process proceeds to step S303, and it is determined, based on a detection signal from brake sensor 77, whether a predetermined braking action continues for a predetermined time or not. If step S303 determines that the braking action continues, the process proceeds to step S302, and it is determined that the vehicle's driving state is the non-acceleration state.

[0039] If step S303 determines that the braking action is not continuing, the process proceeds to step S304, where, based on a detection signal from the vehicle speed sensor 78, it is determined whether a predetermined deceleration state persists for a predetermined time. If step S304 determines that the deceleration state persists, the process proceeds to step S302, where it is determined that the vehicle's driving state is the non-acceleration state. Conversely, if step S304 determines that the deceleration state is not persisting, the process proceeds to step S305, where, based on image information in front of the vehicle and map information at a driving position, it is determined whether the predetermined downhill gradient persists for the predetermined time.If step S305 determines that the downward slope continues, the process proceeds to step S303, and it is determined that the vehicle's driving state is the non-acceleration state.

[0040] If step S305 determines that the downhill slope does not continue, the process proceeds to step S306, where, based on the image information in front of the vehicle, it is determined whether the vehicle should decelerate due to the driving environment. For example, if there is a vehicle ahead, a stop signal, or an intermediate stop line within a predetermined distance of the vehicle, it is determined that the vehicle should decelerate due to the driving environment. If step S306 determines that the vehicle should decelerate in the driving environment, the process proceeds to step S302, where the vehicle's driving status is determined to be non-accelerating. Conversely, if step S306 determines that the vehicle should not decelerate in the driving environment, the process exits the routine without determining the non-acceleration status. [Internal combustion engine rotation process during electric motor operation]

[0041] The following describes a combustion engine rotation process during electric motor operation. As in Fig. As shown in Figure 4, step S10 determines whether the current driving mode is the electric motor driving mode or not. If step S10 determines that the current driving mode is the electric motor driving mode, the process proceeds to step S11, and the combustion engine rotation determination described above is performed, since the internal combustion engine 11 is in the stop state. If, in the subsequent step S12, it is determined that the internal combustion engine rotation is required—in other words, if it is determined that the internal combustion engine rotation is required to ensure booster vacuum, compressor drive, or internal combustion engine braking operation—the process proceeds to step S13, and the aforementioned limit torque determination of the motor-generator 12 is performed.If, in the subsequent step S14, it is determined that the output torque has a limit, in other words, if it is determined that the co-rotating drive can be carried out by increasing the output torque, as described later, the process continues to step S15, and the aforementioned drive status determination is performed.

[0042] If, in the subsequent step S16, it is determined that the vehicle's driving mode is non-acceleration, then, because the switch from electric motor driving mode to co-rotating driving mode is being performed, in step S17 the continuously variable transmission 16 is controlled to shift up towards the acceleration side, i.e., towards the higher gear. In step S18, the combustion engine clutch 17 and the lock-up clutch 36 are engaged. The process then continues to step S19, where the output torque of the motor-generator 12 is applied. As described above, the continuously variable transmission 16 is controlled to shift up, the combustion engine clutch 17 and the lock-up clutch 36 are engaged, and the output torque of the motor-generator 12 is increased, thereby switching the driving mode from electric motor driving mode to co-rotating driving mode.As described above, when the co-rotating drive mode is executed, the internal combustion engine 11 can be rotated while maintaining the fuel lock, and the booster vacuum, compressor drive or internal combustion engine braking operation can be ensured while reducing fuel consumption.

[0043] Furthermore, when the co-rotating drive mode is activated, the combustion engine load can be absorbed by the motor-generator 12 during co-rotating driving because the output torque can be increased further than in the electric motor driving mode. Since the continuously variable transmission 16 shifts up towards the acceleration side when the co-rotating drive mode is activated, the load torque that must be transmitted from the combustion engine 11 to the drive wheels 12 can be reduced. As described above, the output torque is increased or the continuously variable transmission 16 shifts up, which is why, even when the combustion engine clutch 17 is engaged in co-rotating drive mode, excessive deceleration by the combustion engine clutch can be reduced and discomfort for the occupants can be avoided.This means that the continuously variable transmission 16 is shifted up towards the acceleration side by reducing a gear ratio of the continuously variable transmission 16. The gear ratio is the ratio of the input shaft speed to the output shaft speed of the continuously variable transmission 16.

[0044] When the internal combustion engine 11 is rotated by the spin cycle described above, the process proceeds to step S20, and the aforementioned internal combustion engine rotation determination is performed again. If, in the subsequent step S21, it is determined that the internal combustion engine rotation is required—in other words, if it is determined that the internal combustion engine rotation is necessary to ensure booster vacuum, compressor drive, or internal combustion engine braking operation—the process proceeds to step S18, and the spin cycle continues.If, on the other hand, it is determined in step S21 that the combustion engine rotation is unnecessary, in other words, if it is determined that the combustion engine rotation is not required with regard to ensuring booster vacuum, compressor drive or combustion engine braking operation, the process proceeds to step S22, the combustion engine clutch 17 and the bypass clutch 36 are disengaged, and the driving mode switches from the co-rotating driving mode to the electric motor driving mode.

[0045] If, on the other hand, in the subsequent step S14 it is determined that the output torque has no limit, in other words, if it is determined that coasting is difficult due to an increase in output torque, the process continues to step S23, and fuel is injected by the injector to start the internal combustion engine 11. If, in step S16, it is determined that the vehicle's driving state is no longer non-acceleration, in other words, if it is determined that there is a high probability that the accelerator pedal will be pressed by the driver, the process continues to step S23, and fuel is injected by the injector to start the internal combustion engine 11.If a torque deficiency is assumed in the co-rotating driving mode based on the usage status of the motor generator 12 or the driving status of the vehicle, as described above, the internal combustion engine 11 is started while the internal combustion engine clutch 17 is disengaged, without switching the driving mode to the co-rotating driving mode.

[0046] If, as described above, the internal combustion engine 11 is set in motion by fuel injection, the process proceeds to step S24, and the aforementioned determination of the internal combustion engine's rotation is performed again. If, in the subsequent step S25, it is determined that the internal combustion engine's rotation is required—in other words, if it is determined that the internal combustion engine's rotation is necessary to ensure booster vacuum, compressor drive, or internal combustion engine braking operation—the process proceeds to step S23, and the internal combustion engine's rotation is continued by fuel injection.If, on the other hand, it is determined in the subsequent step S25 that the rotation of the internal combustion engine is not required, in other words, if it is determined that the rotation of the internal combustion engine is not required with regard to ensuring booster vacuum, compressor drive or internal combustion engine braking operation, the process proceeds to step S26 and the internal combustion engine 11 is stopped by fuel supply cut-off. [Switching from electric motor to rotary drive]

[0047] The following describes a process for switching from electric motor driving to rotary driving with reference to a time diagram. Fig. Figure 8 is a timing diagram illustrating an example of a process for switching from electric motor drive to wheel-assisted drive. In the Fig. In the driving status shown in section 8, the driving mode switches from electric motor driving mode to traction driving mode while the vehicle is traveling downhill in electric motor driving mode. In the Fig. In Figure 8, the speed shown is denoted by “Ne” as an internal combustion engine speed. Furthermore, “Ni” is an input speed of the internal combustion engine clutch 17, in other words, a speed of the turbine shaft 33, and “No” is an output speed of the internal combustion engine clutch 17, in other words, a speed of the primary shaft 41. To facilitate understanding of the drawings, even though the respective speeds Ne, Ni, and No are identical, these speeds are shown with a slight deviation. Fig. 8 the internal combustion engine clutch 17 is referred to as E / G clutch, and the bridging clutch 36 is referred to as L / U clutch.

[0048] As in Fig. As shown in Figure 8, the booster vacuum P1 decreases when the brake is applied, and when the booster vacuum P1 falls below the predetermined value Px (symbol Xa), it is determined that the combustion engine rotation is required to ensure the booster vacuum P1 (symbol Xb). To determine whether the rotating drive is enabled or not, the limit torque determination of the motor generator 12 is performed. As in the output torque of Fig.As shown in Figure 8, the target torque Tm2 of the motor-generator 12 during synchronous operation is calculated by adding the synchronous torque Tc1 to the output torque Tm1. If the target torque Tm2 falls below the predetermined value Tmx, it is determined that the output torque has a limit (symbol Xc), and switching to synchronous operation is permitted (symbol Xd). If the target torque Tm2 exceeds the predetermined value Tmx, it is determined that the output torque has no limit, and switching to synchronous operation is prevented.

[0049] If, as described above, switching to the side-shift mode is permitted, the continuously variable transmission 16 is activated to shift up to the acceleration side (symbol Xe), the internal combustion engine clutch 17 is activated to engage (symbol Xf), and the lock-up clutch 36 is activated to engage (symbol Xg). In this situation, to suppress excessive acceleration changes of the vehicle, the output torque Tm1 of the motor-generator 12 is increased based on the shift state of the continuously variable transmission, the engagement state of the internal combustion engine clutch 17, and the engagement state of the lock-up clutch 36 (symbol Xh).When the respective engagement of the combustion engine clutch 17 and the bridging clutch 36 is completed, and the input speed Ni and the combustion engine speed Ne have converged to the output speed No (symbol Xi), the switching from electric motor driving mode to co-rotating driving mode is completed.

[0050] When the driving mode switches from electric motor drive to co-rotation drive, as described above, the output torque of the motor-generator 12 is increased (symbol Xh). Consequently, even if the internal combustion engine clutch 17 is disengaged in conjunction with the driving mode change, the internal combustion engine load can be absorbed by the motor-generator 12, thus preventing excessive vehicle deceleration. When the driving mode switches from electric motor drive to co-rotation drive, the gear ratio of the continuously variable transmission 16 is adjusted for acceleration (symbol Xe). Even if the internal combustion engine clutch 17 is engaged in conjunction with the driving mode change, the load torque transmission from the internal combustion engine 11 to the drive wheels 22 can be reduced, thus preventing excessive vehicle deceleration.

[0051] Furthermore, because the gear ratio of the continuously variable transmission 16 is controlled for acceleration in order to reduce the output speed No of the combustion engine clutch 17 (symbol Xj), the speed difference before and after the clutch can be reduced. As a result, the engagement time of the combustion engine clutch 17 can be reduced, and the amount of heat generated in the combustion engine clutch 17 can be decreased. In addition, the gear ratio of the continuously variable transmission 16 is controlled for acceleration in order to reduce the speed of the motor-generator 12 and increase its maximum torque. Because the output torque can be limited with this configuration, the opportunity for spin-start driving can be extended, and fuel consumption can be reduced.

[0052] The present invention is not limited to the example above, but can be modified in various ways without departing from the idea of ​​the present invention. In the description above, the engine control unit 70, the hybrid control unit 71, and the transmission control unit 72 function as the first and second driving control units, respectively, but are not limited to this configuration, and other control units can also function as the first and second driving control units. Alternatively, the first and second driving control units can be configured by a single control unit without using multiple control units.

[0053] In the description above, the combustion engine clutch 17 and the safety clutch 55 are hydraulically actuated, but this configuration is not limited to them. For example, the combustion engine clutch 17 and the safety clutch 55 can each also be configured as an electromagnetic clutch that switches between an engaged and disengaged state by electromagnetic force. Furthermore, the continuously variable transmission 16 is used as the transmission in the description above, but this configuration is not limited to it. A parallel shaft transmission or a planetary gear transmission can also be used as the transmission. In addition, the combustion engine clutch 17 is arranged on the side of the combustion engine 11 with respect to the continuously variable transmission 16 in the description above, but this configuration is not limited to it.The combustion engine clutch 17 can also be arranged on the side of the drive wheels 22 in relation to the continuously variable transmission 16.

[0054] According to the invention, the output torque of the electric motor is increased when the driving mode switches from electric motor driving to co-rotating driving, therefore excessive deceleration of the vehicle can be avoided.

[0055] A vehicle control device comprising an internal combustion engine and an electric motor includes a clutch, a first drive control unit, a second drive control unit, and an electric motor control unit. The clutch is arranged in a power transmission path that couples the internal combustion engine to the drive wheels. The first drive control unit performs an electric motor drive, in which the drive wheels are driven by the electric motor in a state where the clutch is disengaged to decouple the internal combustion engine from the drive wheels, and the internal combustion engine is stopped. The second drive control unit performs a rotating drive, in which the clutch is engaged, while fuel injection from the internal combustion engine is stopped in a state where the electric motor drive is performed, and the internal combustion engine is rotated during the drive.The electric motor control unit increases the output torque of the electric motor when the driving mode switches from electric motor driving to co-rotating driving.

Claims

[1] Vehicle control device (10) comprising an internal combustion engine (11) and an electric motor, wherein the device (10) comprises: a clutch (17) which is arranged in a power transmission path (40) which couples the internal combustion engine (11) and the drive wheels (22); a first driving control device that performs an electric motor drive in which the drive wheels (22) are driven by the electric motor in a state in which the clutch (17) is disengaged to decouple the internal combustion engine (11) from the drive wheels (22) and the internal combustion engine (11) is stopped; a second driving control device that performs a co-rotating drive in which the clutch (17) is engaged, while fuel injection of the internal combustion engine (11) is stopped in a state in which the electric motor drive is performed, and the internal combustion engine (11) is rotated during the drive; an electric motor control device that increases an output torque (Tm1) of the electric motor when the driving mode switches from electric motor driving to pedal-assisted driving; and a transmission mechanism (16) arranged in the power transmission path (40) that couples the internal combustion engine (11) and the drive wheels (22); characterized by a transmission control device (72) that reduces a gear ratio of the transmission mechanism (16) when the driving mode switches from electric motor driving to co-rotating driving, wherein the gear ratio is a ratio of the input shaft speed to the output shaft speed of the transmission mechanism (16). [2] Vehicle control device (10) according to claim 1, wherein the electric motor control device calculates a target torque (Tm2) of the electric motor on the basis of the output torque (Tm1) of the electric motor and a torque capacity of the clutch (17), and the second vehicle control device allows the lateral movement when the target torque (Tm2) falls below a predetermined value, and prevents the lateral movement when the target torque (Tm2) exceeds the predetermined value. [3] Vehicle control device (10) according to claim 1 or 2, which further comprises a vacuum booster (83) coupled to an intake manifold (88) of the internal combustion engine (11). [4] Vehicle control device (10) according to one of claims 1 to 3, which further comprises a compressor (94) coupled to a crankshaft (30) of the internal combustion engine (11).

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