Control device for a hybrid vehicle

Abstract

A control device of a hybrid vehicle suppresses an influence of engagement of a clutch at engine restart on switching of coordinated regenerative control and braking in a hybrid vehicle equipped with a P2 module. The control device of the hybrid vehicle includes an engine (4), a motor (5), a K0 clutch (6), a drive shaft (17), a hydraulic friction brake system (3), and a controller (20) capable of performing coordinated regenerative control. The controller performs, in the coordinated regenerative control, a first process of shifting to braking based on only the friction brake system (3) when start of the engine (4) is requested, a second process of starting engagement of the K0 clutch (6) after the shift of braking is completed and rising an output rotational speed of the engine (4), and a third process of restarting operation of the engine (4) at a timing after the engine rotational speed is raised to coincide with a motor rotational speed after the engagement of the K0 clutch (6) is started.

Description

Technical Field

[0001] This application relates to a control device for hybrid vehicles. Background Technology

[0002] For example, Patent Document 1 discloses a control device for a hybrid vehicle. This hybrid vehicle is equipped with a so-called P2 module.

[0003] Specifically, the hybrid vehicle disclosed in Patent Document 1 includes an engine, a first friction engagement element, an electric generator engaged with the engine via the first friction engagement element, a second friction engagement element sandwiched between the electric generator and the drive wheel, and a coordinated regeneration control mechanism.

[0004] The coordinated regenerative control actuator disclosed in Patent Document 1 prohibits the increase of regenerative torque when the mechanical brake is operated and the friction engagement element is in a sliding state (e.g., when the engine is started), from the time the friction engagement element is engaged until a predetermined time has elapsed. According to Patent Document 1, by prohibiting the increase of regenerative torque, it is possible to prevent the occurrence of vibration caused by undesirable slippage.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 2012-091551 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] However, in hybrid vehicles equipped with a P2 module as disclosed in Patent Document 1, coordinated regeneration control is typically performed when the brake pedal is operated while the clutch clamped between the engine and the electric motor is released. This coordinated regeneration control brakes the drive wheels by coordinating the application of braking force based on the braking system with the regenerative action based on the electric motor.

[0010] Furthermore, there are situations where the engine is requested to restart even when the brake pedal is operated, such as when the vehicle is entering a curve or when the air conditioning is running during deceleration (in other words, during coordinated regenerative control).

[0011] In this case, the braking system switches from coordinated regenerative control to braking using only the brake system, and in order to increase the engine's output speed, it is considered to connect the engine and the motor by engaging the aforementioned clutch.

[0012] However, when using a hydraulic braking system, braking cannot be switched instantaneously. Furthermore, the connection between the engine and the electric motor requires a certain amount of time from engaging the clutch to the point where the output speeds of the engine and the electric motor are synchronized.

[0013] Therefore, assuming that the braking switch and clutch engagement begin approximately simultaneously, the two processes occur concurrently. In this case, adjustments to the output speed, such as changing the regenerative operation of the motor, when the engine's output speed does not change smoothly, may affect the coordinated regenerative control and the switching from this coordinated regenerative control to braking.

[0014] For example, if there is a delay in the increase of the engine's output speed, although it is necessary to request the motor in the regenerative operation to operate, or to reduce the regenerative force of the motor (regenerative braking torque), such processing complicates the coordination of regenerative control, which is therefore disadvantageous.

[0015] This application was made in view of the above circumstances, and its purpose is to suppress the impact of clutch engagement during engine restart on coordinated regenerative control and braking switching in a hybrid vehicle equipped with a P2 module.

[0016] Institutions used to solve problems

[0017] This application relates to a control device for a hybrid vehicle, comprising: an engine that generates driving force for the vehicle; an electric motor capable of performing both power operation and regenerative operation; a first clutch sandwiched between the engine and the electric motor, switching between an engaged state of the engine and the electric motor and a disengaged state of the engine and the electric motor; and an axle sandwiched between the electric motor and the drive wheels of the vehicle. The control device further comprises: a hydraulic friction braking system that distributes braking force to the drive wheels based on the driver's operation of the brake pedal; and a control mechanism capable of performing coordinated regenerative control when the first clutch is disengaged. This coordinated regenerative control refers to controlling braking during vehicle deceleration when the brake pedal is operated by coordinating the distribution of braking force by the friction braking system with the regenerative braking torque supplied to the drive wheels by the electric motor performing regenerative operation.

[0018] Furthermore, according to one aspect of this disclosure, when the control mechanism requests engine start-up during the coordinated regenerative control, it performs the following processes: a first process of transitioning from braking based on the coordinated regenerative control to braking based solely on the friction braking system; a second process of, after the transition to braking based solely on the friction braking system is completed, initiating engagement of the first clutch and causing the motor to perform the power operation or the regenerative operation to increase the engine's output speed; and a third process of, after the engagement of the first clutch begins and the engine's output speed increases to match the motor's output speed, restarting the engine at a certain timing.

[0019] According to this configuration, the hybrid vehicle is a hybrid vehicle equipped with a so-called P2 module that is connected in the order of engine, first clutch, electric motor, second clutch, axle and drive wheels to transmit driving force.

[0020] Furthermore, during vehicle deceleration when the friction braking system distributes braking force to the drive wheels, the electric motor performs regenerative braking. This control is based on coordinated regenerative control of the friction braking system and the electric motor. Through coordinated regenerative control, the regenerative energy stored in the battery, etc., increases. The regenerative braking torque based on the electric motor is applied to the drive wheels. The friction braking system takes into account the regenerative braking torque applied to the drive wheels when distributing braking force to them. As a result, braking in the hybrid vehicle becomes braking that corresponds to the driver's brake pedal operation.

[0021] Here, when the control mechanism requests the engine to start during the coordinated regenerative control, it increases the engine's output speed after the transition from braking based on coordinated regenerative control to braking based solely on the friction braking system is completed.

[0022] Therefore, braking is completed when the engine output speed adjustment begins. As a result, the impact of the output speed adjustment on the coordinated regenerative control and the braking switching performed from that control can be suppressed.

[0023] Alternatively, according to one aspect of this application, the control device of the hybrid vehicle may include a second clutch sandwiched between the motor and the axle, switching between a connected state that engages the motor and the axle and a disengaged state that releases the engagement of the motor and the axle. The second clutch is engaged during the execution of the coordinated regeneration control. In the second process, after the engagement of the first clutch begins, the control mechanism causes the second clutch to slip when the output speed of the motor decreases to less than a predetermined speed.

[0024] According to this configuration, the second clutch is allowed to slip under specified conditions. By allowing the second clutch to slip, the rotational resistance of the motor can be reduced. Therefore, it is possible to suppress the decrease in the motor's output speed.

[0025] Here, as in previously known configurations, if there is no correlation between the timing of slipping the second clutch and the timing of switching to braking based solely on the friction braking system (e.g., when both processes start simultaneously), there is a possibility that the second clutch may slip before the braking switch is completed.

[0026] In this situation, since the regenerative action is performed while the power transmission between the motor and the drive wheel is suppressed, the regenerative braking torque supplied by the motor cannot be fully transmitted to the drive wheel, and there is a possibility that the gears will disengage.

[0027] In the aforementioned configuration, the second clutch slips after the braking switch ends. Therefore, the second clutch can begin to slip even after the regenerative braking torque has been applied (e.g., the regenerative braking torque has been reduced to approximately zero). This prevents gear disengagement from occurring.

[0028] Alternatively, according to one aspect of this application, after the control mechanism makes the output speed of the engine match the output speed of the motor in the third process, if the output speed of the engine and the motor decreases to less than the specified idle speed, it may release the second clutch or allow it to slip, and control the engine in such a way that the output speed rises above the idle speed.

[0029] According to this configuration, the output speed of both the engine and the electric motor can be maintained above idle speed after the engine restarts. Therefore, when acceleration is requested from the hybrid vehicle, such as when switching from pressing the brake pedal to pressing the accelerator pedal, the vehicle can accelerate smoothly.

[0030] Alternatively, according to one aspect of this application, the control mechanism may determine that the engine has been requested to start when the steering angle exceeds a predetermined value during the coordinated regeneration control.

[0031] According to this configuration, when the steering wheel is operated during deceleration while the brake pedal is depressed (in other words, during the coordinated regenerative control execution period), the control mechanism performs the first, second, and third processes. Therefore, for example, when the brake pedal is depressed and the hybrid vehicle enters a curve, the engine can be smoothly restarted without problems such as gear disengagement. This allows for a smoother "slow in, fast out" operation compared to conventional hybrid vehicles, thereby improving the handling of the hybrid vehicle.

[0032] Alternatively, according to one aspect of this application, the control mechanism may determine that the engine has been requested to start when the air conditioner switch accepts the start-up operation during the coordinated regeneration control period.

[0033] According to this configuration, when the air conditioning switch is operated during deceleration when the brake pedal is depressed (in other words, during the coordinated regeneration control execution period), the control mechanism performs the first, second, and third processes. Therefore, for example, if it is desired to operate the air conditioning while the brake pedal is depressed, the engine can be restarted smoothly without causing problems such as gear disengagement. This suppresses vibration during engine restart. Consequently, the ride comfort of the hybrid vehicle can be improved.

[0034] Invention Effects

[0035] As explained above, according to this application, in a hybrid vehicle equipped with a P2 module, the impact of clutch engagement during engine restart on coordinated regenerative control and braking switching can be suppressed. Attached Figure Description

[0036] Figure 1 A hybrid vehicle is shown.

[0037] Figure 2 The engagement table for the automatic transmission is shown.

[0038] Figure 3A This is a block diagram of the control unit for a hybrid vehicle.

[0039] Figure 3B This is a block diagram of a friction braking system.

[0040] Figure 4 This is a flowchart illustrating the processes involved in engine operation.

[0041] Figure 5 This is a flowchart illustrating the processes involved in the motor and brake.

[0042] Figure 6 This is a flowchart illustrating the processes involved in restart control.

[0043] Figure 7 This is a timing diagram of the first, second, and third processes.

[0044] Explanation of reference numerals in the attached figures

[0045] 1. Automobiles (vehicles, hybrid vehicles)

[0046] 17 Drive Axles (Vehicle Axles)

[0047] 19 Brake Pedal

[0048] 20. Controller (Control Mechanism)

[0049] 2R Rear Wheel (Drive Wheel)

[0050] 3. Friction Braking System

[0051] 4 Engines

[0052] 5 motors

[0053] 6K0 clutch (first clutch)

[0054] 8 automatic transmission

[0055] 8d K1 clutch (second clutch)

[0056] 8e Second hydraulic circuit

[0057] 13 First Hydraulic Circuit

[0058] 52. Steering Angle Sensor

[0059] 55 Engine Rotation Sensor

[0060] 56 Motor Rotation Sensor

[0061] 71A / C switch (air conditioner switch)

[0062] 72 Air Conditioner

[0063] 110 Steering Wheel Detailed Implementation

[0064] The following describes an implementation of the control device for a hybrid vehicle. The following description is illustrative.

[0065] (Hybrid vehicles)

[0066] Figure 1 This application describes a vehicle 1 (an example of a vehicle and a hybrid vehicle). The vehicle 1 is a hybrid vehicle that utilizes electricity and is capable of operation. The vehicle 1 has four wheels: a front wheel 2F and a rear wheel 2R. Friction brakes 31 are installed on the front wheel 2F and the rear wheel 2R respectively to brake their rotation.

[0067] The vehicle 1 is equipped with an engine 4 and an electric motor 5 as drive sources to generate the driving force for the vehicle 1. They work together to drive the rear wheels 2R. Thus, the vehicle 1 moves. The vehicle 1 is a rear-wheel drive vehicle. In addition, the electric motor 5 not only serves as a drive source, but also acts as a generator during regeneration. That is, the electric motor 5 in this embodiment can respectively perform the power operation that generates the driving force for the vehicle 1, and the regeneration operation that supplies regenerative energy to the battery (high-voltage battery 9 described later) when the vehicle 1 decelerates.

[0068] The vehicle 1, as described later, is equipped with a high-voltage battery 9 with a rated voltage of 50V or less. Power is supplied from this high-voltage battery 9, and the motor 5 primarily assists the engine 4 in operation. The vehicle 1 is a so-called mild hybrid vehicle. Alternatively, the vehicle 1 can also be a so-called plug-in hybrid vehicle capable of receiving power from an external power source.

[0069] In addition, the car 1 is a hybrid vehicle equipped with a so-called P2 module that connects the driving force in the order of engine 4, first clutch (K0 clutch 6), electric motor 5, second clutch (K1 clutch 8d), axle (drive shaft 17) and drive wheel (rear wheel 2R).

[0070] In the case of car 1, engine 4 is located on the front side of the vehicle body, and drive wheels are located on the rear side of the vehicle body. That is, car 1 is a so-called FR car.

[0071] In addition to the engine 4 and the electric motor 5, the vehicle 1 also includes a K0 clutch 6, an inverter 7, and an automatic transmission 8 as part of its drive system. The vehicle 1 also includes a controller 20 as part of its control system. Furthermore, the vehicle 1 includes a hydraulic friction braking system 3 containing a friction brake 31 as part of its braking system.

[0072] (Drive system device)

[0073] Engine 4 is, for example, an internal combustion engine that burns fossil fuels. Alternatively, engine 4 is a so-called four-stroke engine that generates rotational power through repeated intake, compression, expansion, and exhaust strokes. Engine 4 is configured as a diesel engine with a compression ignition mechanism, but it can also be a spark-ignition engine, other compression ignition engines, or various other types and forms. Engine 4 operates by injecting fuels such as fossil fuels and burning those fuels inside the cylinder.

[0074] In this automobile 1, the engine 4 is positioned approximately at the center in the width direction of the vehicle, with the crankshaft 4a, which outputs rotational power, facing the front-rear direction of the vehicle body. The automobile 1 is equipped with various devices and mechanisms attached to the engine 4, such as an intake system, an exhaust system, and a fuel supply system.

[0075] Motor 5 is a three-phase AC-driven permanent magnet synchronous motor. Motor 5 is connected in series behind engine 4 via clutch K0 6. Motor 5 is also connected in series in front of automatic transmission 8.

[0076] The K0 clutch 6 is clamped between the engine 4 and the motor 5. Specifically, the K0 clutch 6 is configured to be clamped between the front end of the shaft 5a of the motor 5 and the crankshaft 4a of the engine 4. The K0 clutch 6 switches between a state in which the crankshaft 4a and shaft 5a are connected (connected state) and a state in which the crankshaft 4a and shaft 5a are separated (disconnected state).

[0077] The K0 clutch 6 is engaged when the engine 4 and the electric motor 5 are connected. The K0 clutch 6 is disengaged when it is released (cut off). The K0 clutch 6 functions as the "first clutch" in this embodiment. The switching between the engagement and disengagement states of the K0 clutch 6, as the first clutch, is achieved by the first hydraulic circuit 13 (only...). Figure 3A (As shown) the hydraulic control is performed.

[0078] The rear end of the shaft 5a of the motor 5 is connected to the input shaft 8a of the automatic transmission 8. Therefore, the engine 4 is connected to the automatic transmission 8 via the K0 clutch 6 and the shaft 5a. By disengaging the K0 clutch 6, the engine 4 is disconnected from the automatic transmission 8.

[0079] During the movement of vehicle 1, clutch 6 (K0) switches between engaged and disengaged states. For example, when vehicle 1 decelerates, there is a possibility that clutch 6 (K0) is disengaged and regeneration occurs while engine 4 is off. For example, in the coordinated regeneration control described later, motor 5 can perform regeneration operation while the first clutch (K0) is disengaged. Furthermore, clutch 8d (K1), which is the second clutch, is engaged during coordinated regeneration control.

[0080] The motor 5 is connected to the high-voltage battery 9, which serves as the drive power source, via the inverter 7 and the high-voltage cable 40. In the case of this vehicle 1, the rated voltage of the high-voltage battery 9 is 50V or less, specifically a 48V DC battery.

[0081] The high-voltage battery 9 supplies high-voltage direct current to the inverter 7. The inverter 7 converts this direct current into three-phase alternating current and powers the motor 5. This drives the motor 5 to rotate. Additionally, the motor 5 supplies regenerative energy to the high-voltage battery 9.

[0082] The high-voltage battery 9 is also connected to the DC-DC converter 10 via the high-voltage cable 40. The DC-DC converter 10 converts the 48V high-voltage DC voltage to a low-voltage 12V DC power and outputs it. The DC-DC converter 10 (its output side) is connected to the low-voltage battery 11 (a so-called lead-acid battery) via the low-voltage cable 41.

[0083] The low-voltage battery 11 is connected to various electrical components via a low-voltage cable 41. The DC-DC converter 10 is also connected to the CAN 12 (Controller Area Network) via the low-voltage cable 41. Thus, the DC-DC converter 10 supplies low-voltage DC power to the CAN 12.

[0084] The automatic transmission 8 is a hydraulically controlled multi-stage automatic transmission (so-called AT). This automatic transmission 8 has an input shaft 8a connected to the engine 4 and an output shaft 8b connected to the drive wheels (rear wheels 2R) of the vehicle 1. This automatic transmission 8 is capable of shifting the rotational speed input to the input shaft 8a and outputting it at a gear ratio corresponding to the gear selected by the occupants.

[0085] In detail, the input shaft 8a is located at the front end of the automatic transmission 8. This input shaft 8a is connected to the shaft 5a of the motor 5 as described above. The output shaft 8b is located at the rear end of the automatic transmission 8. This output shaft 8b rotates independently of the input shaft 8a.

[0086] A transmission mechanism consisting of a torque converter 8c, multiple planetary gear mechanisms, and multiple friction engagement elements is assembled between the input shaft 8a and the output shaft 8b. Each friction engagement element switches between an engaged state and a disengaged state via hydraulic pressure.

[0087] Figure 2 This is an engagement table for the automatic transmission 8. Circles in the table indicate engagement. The automatic transmission 8 is equipped with three clutches—a first clutch CL1, a second clutch CL2, and a third clutch CL3—and two brakes—a first brake BR1 and a second brake BR2—as friction engagement elements. The automatic transmission 8 also has a second hydraulic circuit 8e for switching these friction engagement elements between an engaged state (connected state) and a disengaged state (disengaged state) (only applicable to...). Figure 3A (as shown in the image).

[0088] The automatic transmission 8 selects three elements from the three clutches and two brakes to engage via hydraulic control based on the second hydraulic circuit 8e. This allows the automatic transmission to switch between one of the forward gears (1 to 8 speeds) or the reverse gear (reverse speed).

[0089] Specifically, the engagement of the first clutch CL1, the first brake BR1, and the second brake BR2 creates a 1st speed. The engagement of the second clutch CL2, the first brake BR1, and the second brake BR2 creates a 2nd speed. The engagement of the first clutch CL1, the second clutch CL2, and the second brake BR2 creates a 3rd speed. The engagement of the second clutch CL2, the third clutch CL3, and the second brake BR2 creates a 4th speed. The engagement of the first clutch CL1, the third clutch CL3, and the second brake BR2 creates a 5th speed. The engagement of the first clutch CL1, the second clutch CL2, and the third clutch CL3 creates a 6th speed. The engagement of the first clutch CL1, the third clutch CL3, and the first brake BR1 creates a 7th speed. The engagement of the second clutch CL2, the third clutch CL3, and the first brake BR1 creates an 8th speed. The engagement of the third clutch CL3, the first brake BR1, and the second brake BR2 creates a reverse speed.

[0090] Furthermore, for example, when upshifting from 1st speed, the transmission shifts from 1st to 2nd speed by engaging the second clutch CL2 instead of the first clutch CL1. The transmission shifts from 2nd to 3rd speed by engaging the first clutch CL1 instead of the first brake BR1. The transmission shifts from 3rd to 4th speed by engaging the third clutch CL3 instead of the first clutch CL1.

[0091] Upshifting to 5th gear and beyond is performed in the same manner as described above. Downshifting, however, follows the reverse sequence of gear changes.

[0092] If the elements that should be engaged in each gear shift are not engaged, the input shaft 8a and the output shaft 8b are disconnected (so-called neutral). Even if rotational power is input to the automatic transmission 8 from the drive source, that rotational power is not output from the automatic transmission 8.

[0093] In this embodiment, there is a possibility that the automatic transmission 8 will shift into neutral when the second clutch CL2 or the third clutch CL3 is released during the deceleration of the vehicle 1. Specifically, when the automatic transmission 8 is in 2-speed, 3-speed, or 4-speed mode, the automatic transmission 8 will shift into neutral when the second clutch CL2 is released. Furthermore, when the automatic transmission 8 is in 5-speed, 6-speed, 7-speed, or 8-speed mode, the automatic transmission 8 will shift into neutral when the third clutch CL3 is released.

[0094] In the following description, these second clutches CL2 and third clutches CL3 are sometimes collectively referred to as K1 clutch 8d (see reference). Figure 3ADuring the deceleration of car 1, releasing clutch K1 8d means cutting off the power transmission between the input shaft 8a and the output shaft 8b of automatic transmission 8, thus setting automatic transmission 8 to neutral.

[0095] like Figure 1 As shown, the output shaft 8b of the automatic transmission 8 is connected to the differential gear 16 via a drive shaft 15 extending in the longitudinal direction of the vehicle body. A pair of drive shafts 17, 17 extending in the width direction and connected to the left and right rear wheels 2R, 2R are connected to the differential gear 16. The rotational power output via the drive shaft 15 is distributed by the differential gear 16 and then transmitted to each rear wheel 2R via the pair of drive shafts 17, 17. The pair of drive shafts 17, 17 function as "axles" sandwiched between the motor 5 and the drive wheels (the left and right rear wheels 2R, 2R).

[0096] While the vehicle 1 is in motion, clutch 8d K1 switches between an engaged state and a disengaged state. Here, the engaged state of clutch 8d is the state in which motor 5 is engaged with a pair of drive shafts 17, 17 that serve as drive wheels. The disengaged state of clutch 8d K1 is the state in which this engagement is released (disengaged).

[0097] Clutch K1 8d functions as the "second clutch" in this embodiment. The switching between the engagement and disengagement states of clutch K1 8d as the second clutch is performed by hydraulic control via the second hydraulic circuit 8e, as described above.

[0098] (Control device for hybrid vehicles)

[0099] Figure 3A This is a block diagram of the control device for a hybrid vehicle. The aforementioned controller 20 is installed in the vehicle 1 to control the engine 4, electric motor 5, K0 clutch 6, automatic transmission 8, friction braking system 3, etc., according to the driver's operation, thereby controlling the movement of the vehicle 1.

[0100] The controller 20 consists of hardware such as a processor, memory, and interfaces, as well as software such as a database and control programs. Additionally, Figure 3A The control device shown includes a controller 20, but the controller can also be divided into a PCM unit that primarily controls the operation of the drive sources (engine 4 and motor 5) and a TCM unit that primarily controls the operation of the K0 clutch 6 and the automatic transmission 8. The PCM and TCM are connected via CAN 12 and configured to communicate with each other electrically. The PCM also functions as the brake ECU for controlling the friction braking system 3. Alternatively, the brake ECU can be separated from the PCM. The controller 20 functions as the "control mechanism" in this embodiment.

[0101] The control unit of a hybrid vehicle includes sensors that measure various parameters related to vehicle operation, as well as switches that detect driver actions. Specifically, the transmission control unit includes a vehicle speed sensor 51, a steering angle sensor 52, a brake pedal sensor 53, an accelerator opening sensor 54, an engine rotation sensor 55, an electric motor rotation sensor 56, and an A / C switch 71.

[0102] Vehicle speed sensor 51 outputs a signal corresponding to the vehicle's speed. Steering angle sensor 52 outputs the steering wheel angle of the steering wheel 110 (reference). Figure 1 The rotation angle of the steering angle, in other words, the output signal corresponding to the steering angle (turning angle).

[0103] Brake pedal sensor 53 outputs the brake pedal 19 operated by the driver (see reference). Figure 1 The accelerator pedal is activated by the driver's input signal (see accelerator pedal 18). The accelerator pedal position sensor 54 outputs a signal corresponding to the driver's input signal. Figure 1 The signal corresponding to stepping on the ground.

[0104] The engine rotation sensor 55 outputs a signal corresponding to the output speed of the engine 4 (engine speed), which is the speed of the crankshaft 4a. The motor rotation sensor 56 outputs a signal corresponding to the output speed of the motor 5 (motor speed), which is the speed of the motor 5's shaft 5a, and also the speed of the automatic transmission 8's input shaft 8a.

[0105] The A / C switch 71 is used to switch only when... Figure 3A The switch shown in the diagram is used to switch the air conditioner 72 between on and off states. When the driver turns on the air conditioner 72, the A / C switch 71 outputs a signal corresponding to that operation.

[0106] The controller 20 receives signals from these sensors and switches via CAN 12. The controller 20 outputs control signals to the engine 4, inverter 7, first hydraulic circuit 13, second hydraulic circuit 8e, air conditioner 72, and friction braking system 3 via CAN 12. Thus, the controller 20 controls the engine 4, motor 5, K0 clutch 6, automatic transmission 8, air conditioner 72, and friction braking system 3.

[0107] For example, when the controller 20 performs an operation to turn on the A / C switch 71 to set the air conditioner 72 to the on state, it uses the driving force of the engine 4 to make the compressor of the air conditioner 72 work.

[0108] In addition, the controller 20 controls the friction braking system 3 for braking the car 1. Figure 3B This is a block diagram of friction braking system 3. Figure 3BThe friction braking system 3 shown distributes braking force to the front wheels 2F and rear wheels 2R of the vehicle 1 according to the operation of the brake pedal 19 in order to achieve braking. This friction braking system 3 is a hydraulically controlled friction braking system.

[0109] like Figure 3B As shown, the friction braking system 3 includes the four friction brakes 31 described above (in... Figure 3B The figure shows only one of the master cylinder 32 and the braking mechanism 33.

[0110] The master cylinder 32 transmits the force applied to the brake pedal 19 to the brake fluid, converting it into hydraulic pressure. The braking mechanism 33 receives an electrical signal from the controller 20 (described later) and switches the hydraulic circuit.

[0111] Furthermore, the braking mechanism 33 controls the hydraulic pressure acting on the front and rear friction brakes 31 by switching the hydraulic circuit. The level of hydraulic pressure corresponds to the level of braking force distributed by the friction brakes 31. That is, when the hydraulic pressure is lower, the braking force is lower compared to when the hydraulic pressure is higher.

[0112] To determine the hydraulic pressure level in the friction braking system 3, the controller 20 in this embodiment is electrically connected to a brake hydraulic pressure sensor 57 (only when...). Figure 3A (See diagram). The brake hydraulic sensor 57 detects the hydraulic pressure in the friction braking system 3 and inputs a signal indicating its detection result to the controller 20.

[0113] Furthermore, during vehicle deceleration when the brake pedal 19 is operated, the controller 20 of this embodiment performs coordinated regenerative control (first regenerative control) to provide a portion of the driver's requested braking force using the regenerative braking torque of the motor 5. In this case, the hydraulic pressure of the friction brake 31 decreases the amount of regenerative braking torque of the motor 5.

[0114] The coordinated regenerative control configuration is such that braking is performed by coordinating the distribution of braking force based on the friction braking system 3 with the regenerative action based on the motor 5 (more specifically, by causing the motor 5 to perform a regenerative action to impart regenerative braking torque to the rear wheel 2).

[0115] Coordinated regeneration control can be performed with the K0 clutch 6 disengaged. By performing coordinated regeneration control with the K0 clutch 6 disengaged, the motor 5 can perform regeneration without being hindered by engine braking. This ensures a greater amount of electricity generated by the motor 5.

[0116] Furthermore, in this embodiment, when the controller 20 requests the restart of the engine 4 during coordinated regeneration control, it can perform restart control consisting of multiple processes. Hereinafter, the overall processing performed by the controller 20, including the processes related to this restart control, will be described.

[0117] (Holistic approach)

[0118] Figure 4 This is a flowchart illustrating the processing of engine 4. Additionally, Figure 5 This is a flowchart illustrating the processing of motor 5 and brake (friction braking system 3). Figure 4 Control process and Figure 5 The control procedures are not performed sequentially, but rather are carried out by both parties roughly simultaneously.

[0119] First of all, Figure 4 In step S11, the controller 20 reads inputs from various sensors and switches. In the next step S12, the controller 20 determines whether the driver has pressed the accelerator pedal 18. This determination is based on the signal from the accelerator opening sensor 54.

[0120] If the determination in step S12 is yes, in other words, if the driver has pressed the accelerator pedal 18, the controller 20 advances the control process to step S13. If the determination in step S12 is no, in other words, if the driver has not pressed the accelerator pedal 18, the controller 20 advances the control process to step S16.

[0121] In addition, the content of step S11 is the same as Figure 5 Step S31 is the same. The content of step S12 is the same. Figure 5 The same applies to step S32. For ease of explanation, steps S11 and S31, as well as steps S12 and S32, are represented on separate flowcharts. However, these steps are not performed as independent processes, but rather as a common process within the engine 4, motor 5, and friction braking system 3.

[0122] For example, if the determination in step S32 is yes, in other words, if the driver has pressed the accelerator pedal 18, the controller 20 advances the control process to step S33. If the determination in step S32 is no, in other words, if the driver has not pressed the accelerator pedal 18, the controller 20 advances the control process to step S36.

[0123] (Accelerating request processing)

[0124] Figure 4 Steps S13 to S15, and Figure 5The processing in steps S31 to S33 mainly occurs when the vehicle 1 requests acceleration. That is, when the process proceeds to steps S13 and S23, the controller 20 determines that the vehicle 1 should be accelerated and executes the control corresponding to its determination.

[0125] Specifically, in Figure 4 In step S13, the controller 20 engages both clutches K0 6 and K1 8d. This engagement is performed by the controller 20 controlling the first hydraulic circuit 13 and the second hydraulic circuit 8e. Furthermore, once both clutches K0 6 and K1 8d are engaged, the controller 20 maintains their engagement.

[0126] In step S14, the controller 20 determines the driving force required to activate the engine 4 and the motor 5 as a whole, based on the amount of pressure applied to the accelerator pedal 18 and the current vehicle speed. This determination is based on signals from the accelerator opening sensor 54 and the vehicle speed sensor 51. Furthermore, the controller 20 determines the driving force that should be applied to the engine 4 based on the driving force determined as described above.

[0127] Subsequently, in step S15, the controller 20 determines the amount of fuel injection, etc., in a manner that achieves the driving force determined in step S14, and controls the engine 4 based on the various parameters determined in this way.

[0128] In contrast, Figure 5 The content of step S33 is the same as that of step S13 described above. For ease of explanation, steps S33 and S13 are shown on separate flowcharts, but each step is not performed as an independent process, but rather as a common process in engine 4, motor 5, and friction braking system 3.

[0129] Subsequently, in step S34 following step S33, the controller 20 determines the driving force required to activate the engine 4 and motor 5 based on the amount of pressure applied to the accelerator pedal 18 and the current vehicle speed. This process is the same as that described in step S14. Furthermore, the controller 20 determines the driving force that should be applied to the motor 5 based on the driving force determined as described above.

[0130] Subsequently, in step S35, the controller 20 determines the control parameters of the motor 5 in a manner that achieves the driving force determined in step S34, and causes the motor 5 to perform power operation based on the various parameters thus determined.

[0131] (Handling when there is no acceleration request and the brake pedal is not in operation)

[0132] Figure 4 Steps S16 to S24, and Figure 5The processing in steps S36 to S45 is mainly performed when there is no acceleration request from the vehicle 1 (especially when the vehicle is decelerating). When proceeding to steps S16 and S36, the controller 20 performs processing corresponding to the operating status of the brake pedal 19, etc. Hereinafter, the processing performed when there is no acceleration request without pressing the accelerator pedal 18 (when the accelerator pedal 18 is not operated) will be described in detail.

[0133] First, the control procedures related to engine 4 proceed to the point where, in the absence of a non-acceleration request and accelerator pedal 18 is not depressed. Figure 4 Step S16. In step S16, the controller 20 determines whether the air conditioner 72 is in the off state. This determination is based on the signal from the A / C switch 71.

[0134] If the determination in step S16 is yes, in other words, if the air conditioner 72 is in the off state (if the air conditioner 72 is not activated), the controller 20 advances the control process to step S17. If the determination in step S16 is no, in other words, if the air conditioner 72 is in the on state, the controller 20 advances the control process to step S18.

[0135] Furthermore, in step S17 following step S16, the controller 20 determines whether the driver has pressed the brake pedal 19. This determination is based on the signal from the brake pedal sensor 53. If the determination in step S17 is yes, in other words, if the driver has pressed the brake pedal 19, the process proceeds to step S22. If the determination in step S17 is no, in other words, if the driver has not pressed the brake pedal 19, the process proceeds to step S18.

[0136] Upon proceeding to step S22, fuel injection is stopped on the engine 4 side, while coordinated regeneration control is performed on the motor 5 and friction braking system 3 sides according to vehicle speed. This control is performed with the K0 clutch 6 released, depending on the operating status of the A / C switch 71.

[0137] On the other hand, if the process proceeds to step S18 instead of step S22, the car 1 decelerates more slowly compared to when the brake pedal 19 is operated. In this case, the controller 20 performs processing that takes into account factors such as suppressing engine shutdown.

[0138] Specifically, in step S18, the controller 20 determines whether the engine speed (Ne) is greater than a predetermined first threshold (N1) (Ne > N1?). This determination is based on the signal from the engine rotation sensor 55.

[0139] Here, if the determination in step S18 is yes, in other words, if the engine speed is greater than the first threshold, the controller 20 advances the control process to step S19. If the process advances to step S19, the controller 20, after stopping the fuel injection of the engine 4, advances the control process to step S20.

[0140] On the other hand, if the determination in step S18 is negative, in other words, if the engine speed is below the first threshold, the controller 20 skips step S19 and proceeds to step S20. In this case, the controller 20 continues fuel injection into the engine 4. This suppresses engine stalling that occurs during deceleration.

[0141] In step S20, the controller 20 determines whether the motor speed (Nm) is less than a predetermined second threshold (N2) (Nm < N2?). This determination is based on the signal from the motor rotation sensor 56.

[0142] Here, if the determination in step S20 is yes, in other words, if the motor speed is less than the second threshold, the controller 20 advances the control process to step S21. Upon advancing to step S21, if fuel injection was stopped in step S19 above, the controller 20 restarts fuel injection. Figure 5 As also shown in step S40, the controller 20, together with the restart of fuel injection, causes the K1 clutch 8d to slip. This control prevents engine stalling.

[0143] On the other hand, if the determination in step S20 is negative, in other words, if the motor speed is above the second threshold, the controller 20 skips step S21 and returns to the control process.

[0144] In contrast, the control procedures related to motor 5 and friction braking system 3 proceed to [the next step] when there is no acceleration request. Figure 5 Step S36. In step S36, the controller 20 determines whether the vehicle speed (Vv) of the car 1 is greater than a predetermined first speed (V1) (Vv>V1?). This determination is based on the signal from the vehicle speed sensor 51.

[0145] If the determination in step S36 is yes, in other words, if the vehicle speed is greater than the first speed, controller 2 advances the control process to the latter part of step S35. In this case, the control process returns without any special processing.

[0146] On the other hand, if the determination in step S36 is negative, in other words, if the driver has not pressed the brake pedal 19, the process proceeds to step S37. In step S37, the controller 20 determines whether the driver has pressed the brake pedal 19. This determination is based on the signal from the brake pedal sensor 53.

[0147] If the determination in step S37 is yes, in other words, if the driver has pressed the brake pedal 19, the process proceeds to step S41. If the determination in step S37 is no, in other words, if the driver has not pressed the brake pedal 19, the process proceeds to step S38.

[0148] Upon proceeding to step S41, coordinated regeneration control is performed on the side of motor 5 and friction braking system 3, while on the other hand, fuel injection is stopped on the engine 4 side depending on the operating status of A / C switch 71. These controls can be performed with clutch 6 released.

[0149] On the other hand, if the process proceeds to step S38 instead of step S42, the car 1 decelerates more slowly compared to when the brake pedal 19 is operated. In this case, the controller 20 performs processing that takes into account factors such as suppressing engine stall.

[0150] Specifically, in step S38, which is entered when the driver does not decelerate by pressing the brake pedal 19, the controller 20 begins a second regenerative control that is equivalent to engine braking.

[0151] The second regenerative control is a regenerative control performed during the deceleration of the vehicle 1 when the friction braking system 3 does not apply braking force to the front wheels 2F and the rear wheels 2R. It is called "motor regeneration" by causing the motor 5 to perform a regenerative action to apply regenerative braking torque to the rear wheels 2R.

[0152] After initiating the second regenerative control in step S38, controller 20 monitors the motor speed. Specifically, in step S39 following step S38, controller 20 determines whether the motor speed (Nm) is less than a predetermined second threshold (N2) (Nm < N2?). This determination is based on the signal from motor rotation sensor 56.

[0153] Here, if the determination in step S39 is yes, in other words, if the motor speed is less than the second threshold, the controller 20 advances the control process to step S40. Upon advancing to step S40, the controller 20 causes the K1 clutch 8d to slip (K1 slip). Furthermore, the controller 20 terminates the second regeneration control (motor regeneration) that began in step S38 above. Through this control, engine stalling is prevented.

[0154] On the other hand, if the determination in step S39 is negative, in other words, if the motor speed is above the second threshold, the controller 20 skips step S40 and returns to the control process.

[0155] (Handling when there is no acceleration request and when the brake pedal is operated)

[0156] When a non-acceleration request is made while the brake pedal 19 is depressed (during operation of the brake pedal 19), the control process sends... Figure 4 Step S22, and Figure 5 Proceed to step S41. The handling of these cases will be explained below.

[0157] First, in step S22, corresponding to the control process of engine 4, controller 20 stops fuel injection into engine 4. As a result, the engine speed reaches zero. In parallel with the cessation of fuel injection, controller 20, as needed, performs the aforementioned coordinated regenerative control via motor 5 and friction braking system 3 while clutch K0 is released.

[0158] Afterwards, the controller 20 stops the fuel injection of the engine 4 and continues the coordinated regenerative control by the motor 5 and the friction braking system 3.

[0159] Then, in step S23 after step S22, the controller 20 determines in the coordinated regeneration control whether the engine 4 has been requested to start.

[0160] Specifically, in this embodiment, the controller 20 determines that the engine 4 has been requested to start when the steering angle exceeds a predetermined value (α) during coordinated regeneration control, or when the A / C switch (air conditioning switch) 71 is turned on during coordinated regeneration control. The former determination is based on the signal from the steering angle sensor 52.

[0161] Here, if the determination in step S23 is yes, the controller 20 advances the control process to step S24. In this case, the control processes on the motor 5 and friction braking system 3 sides also advance to the steps corresponding to step S24. Figure 5 Step S45.

[0162] In step S24, controller 20 performs coordinated restart control of engine 4, motor 5, and friction braking system 3. Once the restart control is completed, controller 20 returns the control process to normal.

[0163] In contrast, if the determination in step S23 is negative, the control process skips step S24 and returns. In this case, restart control is not performed.

[0164] On the other hand, in step S41, corresponding to the control process of the motor 5 and the friction braking system 3, the controller 20 determines whether the air conditioner 72 is in the off state. This determination is based on whether the A / C switch 71 has accepted the opening operation and the signal from the A / C switch 71.

[0165] If the determination in step S41 is yes, in other words, if the air conditioner 72 is in the off state (the air conditioner 72 is not driven), the controller 20 advances the control process to step S42. In step S42, the controller 20 releases the K0 clutch 6. This disconnects the power transmission between the engine 4 and the motor 5. If the processing in step S42 is complete, the controller 20 advances the control process to step S43 and begins coordinated regeneration control.

[0166] On the other hand, if the determination in step S41 is negative, in other words, if the air conditioner 72 is in the on state (when the A / C switch 71 accepts the on operation), the control process skips step S42 and proceeds to step S43. In other words, when the brake pedal 19 is pressed and the A / C switch 71 accepts the on operation, the controller 20 does not release the K0 clutch 6 and begins to coordinate regenerative control.

[0167] In step S43, the controller 20 performs coordinated regenerative control to provide a portion of the driver's requested braking force using the regenerative braking torque of the motor 5. Additionally, the hydraulic pressure of the friction brake 31 decreases by the amount of regenerative braking torque from the motor 5. The braking force generated by the friction braking system 3 reduces the amount of hydraulic pressure decrease in the friction brake 31.

[0168] Then, in step S44 after step S43, the controller 20 determines whether the engine 4 has been requested to start in the coordinated regeneration control.

[0169] In addition, the content of step S44 is the same as Figure 4 Step S23 is the same. For ease of explanation, steps S44 and S23 are shown in separate flowcharts, but these steps are not performed as independent processes, but as a common process in the engine 4, motor 5, and friction braking system 3.

[0170] Here, if the determination in step S44 is yes, the controller 20 advances the control process to step S45 and executes restart control. Once the restart control is completed, the controller 20 returns the control process.

[0171] In contrast, if the determination in step S44 is negative, the control process skips step S45 and returns. In this case, restart control is not performed.

[0172] (Restart control)

[0173] Figure 6 This is a flowchart illustrating the processes related to restart control. First, in... Figure 6 In step S51, the controller 20 performs a first process of switching from braking based on coordinated regenerative control to braking based solely on the friction braking system 3. The controller 20 replaces braking based on coordinated regenerative control with braking based solely on the friction brake 31. With this replacement, the requested braking force, including the amount currently provided by the regenerative braking torque of the motor 5, will be entirely provided by the friction braking system 3.

[0174] Specifically, in step S51, the controller 20 increases the braking force of the friction brake 31 in a manner that compensates for the amount provided by the regenerative braking torque of the motor 5. The controller 20 increases the hydraulic pressure of the friction brake 31 by the amount of the regenerative braking torque of the motor 5. The braking force caused by the friction braking system 3 increases by the amount of hydraulic pressure increase in the friction brake 31.

[0175] However, the hydraulic pressure of the friction brake 31 is not adjusted instantaneously. Therefore, in step S52 following step S51, the controller 20 determines whether the transition to braking based solely on the friction braking system 3 has been completed. This determination is based on the signal from the brake hydraulic pressure sensor 57.

[0176] In subsequent steps S53 to S55, after the transition to braking based solely on the friction braking system 3 is completed, the controller 20 begins to engage the K0 clutch 6 and causes the motor 5 to perform a power operation or a regeneration operation, thereby executing a second process that increases the engine speed.

[0177] Specifically, in step S53, the controller 20 determines whether the K0 clutch 6 is in the process of being released. If the determination is yes, the controller 20 proceeds the control process to step S55 via step S54. On the other hand, if the determination in step S53 is no, the controller 20 skips step S54 and proceeds to step S55.

[0178] In step S54, the controller 20 initiates engagement of the K0 clutch 6 via the first hydraulic circuit 13. The K0 clutch 6 is engaged while sliding.

[0179] The K0 clutch 6 is gradually engaged via step S54, or, if step S54 is skipped, the K0 clutch 6 is already engaged, thereby driving the crankshaft 4a to rotate via the motor 5. At this time, the engine speed can be increased either by transmitting the regenerative action of the motor 5 to the crankshaft 4a or by transmitting the power operation action of the motor 5 to the crankshaft 4a.

[0180] Furthermore, engagement with engine 4 creates rotational resistance for motor 5. Therefore, if clutch 6 is engaged and engine speed begins to increase, motor speed, and consequently vehicle speed, gradually decreases. Thus, motor 5 can also operate with increasing engine speed, thereby gradually increasing the output torque of motor 5.

[0181] Therefore, as shown in step S55 following step S54, engine starting (increase in engine speed) begins by transmitting the rotation of motor 5 to engine 4. Furthermore, in step S55, motor 5 is not used for drive force control to output the driving force of vehicle 1, but rather for start-up control to increase engine speed.

[0182] Afterwards, once the K0 clutch 6 has engaged, the controller 20 executes a third process to restart the engine 4 at a timed interval after the engine speed has risen to match the motor speed.

[0183] Specifically, in step S56 following step S55, the controller 20 determines whether the engine speed is consistent with the motor speed (Ne = Nm?). This determination is based on the signals from the engine rotation sensor 55 and the motor rotation sensor 56.

[0184] If the determination in step S56 is yes, the controller 20 advances the control process to step S59. In step S59, the controller 20 determines that the engine 4 has been started.

[0185] On the other hand, if the determination in step S56 is negative, the controller 20 advances the control process to step S57. In step S57, the controller 20 determines whether the motor speed is lower than a predetermined second threshold (N2) (Nm < N2?). This determination is based on the signal from the motor rotation sensor 56.

[0186] If the determination in step S57 is negative, the controller 20 skips the subsequent step S58 and returns to the process described in step S56. In other words, the determination in step S57 is repeated until the engine speed matches the motor speed.

[0187] On the other hand, if the determination in step S57 is yes, the controller 20 advances the control process to step S58. In step S58, the controller 20 causes the K1 clutch 8d to slip (K1 slip) in order to cut off or ease the power transmission between the axle and the motor 5.

[0188] Thus, the controller 20 is configured such that, after the engagement of the K0 clutch 6 begins in the second process, the K1 clutch 8d slips when the output speed of the motor 5 decreases to less than a second threshold value which is a predetermined speed.

[0189] If the determination in step S56 is yes, then in the subsequent step S59, it is determined that the engine 4 has been started successfully, as described above. Therefore, in the subsequent step S60, the controller 20 restarts fuel injection into the engine 4. Thus, the engine 4 restarts operation.

[0190] In step S60, the engine 4 and the electric motor 5 coordinate with each other to output the driving force for the vehicle 1. At this time, the controller 20 controls the engine 4 and the electric motor 5 to achieve a deceleration corresponding to the amount of braking of the brake pedal 19. However, excessive or prolonged deceleration may cause the engine to stall.

[0191] Therefore, in step S61 following step S60, controller 20 performs idle speed control of vehicle 1. Specifically, in step S61, controller 20 determines whether the engine speed and motor speed are lower than the specified idle speed (e.g., the aforementioned second threshold) (Ne < N2? or Nm < N2?). If the determination is yes, controller 20 releases clutch K1 8d or causes it to slip.

[0192] In addition to releasing or slipping the K1 clutch 8d, the controller 20 further maintains the engine speed or motor speed above the aforementioned specified speed by adjusting the output torque of the engine 4 and the motor 5. At this time, the controller 20 can also increase the fuel injection quantity of the engine 4. Furthermore, besides increasing the fuel injection quantity, idle speed control can be assisted by enhancing the power operation of the motor 5 or weakening the regenerative operation of the motor 5.

[0193] Thus, in the third process, after the output speed of the engine 4 is made to match the output speed of the motor 5 (for example, after the engine 4 is restarted), when the output speed of the engine 4 and the motor 5 decreases to a speed lower than the specified idle speed, the controller 20 releases the K1 clutch 8d or allows it to slip, and performs idle speed control on the engine 4 in such a way that the output speed of the engine 4 and the motor 5 rises to a speed higher than the idle speed.

[0194] (Control Example)

[0195] Next, refer to Figure 7 The timing diagram illustrates the first, second, and third processes. This timing diagram includes the coordinated regeneration indicator, steering angle indicator, restart indicator, operation status of accelerator pedal 18, operation status of brake pedal 19, changes in vehicle speed, changes in motor speed, and changes in engine speed.

[0196] Here, the coordinated regeneration indicator becomes 1 when it is determined that coordinated regeneration control should be executed. The steering angle indicator becomes 1 when a signal from the steering angle sensor is detected (when the steering wheel 110 is operated). The restart indicator becomes 1 when it is determined that restart control should be executed. The accelerator pedal 18 is ON when the accelerator pedal 18 is operated and OFF when it is not operated. The brake pedal 19 is ON when the brake pedal 19 is operated and OFF when it is not operated.

[0197] First, when the accelerator pedal 18 is not in operation (in other words, when the car 1 is decelerating), at time t0, let's say the brake pedal 19 is depressed. In this case, before time t0, since the engine 4 has stopped (fuel injection has stopped), the engine speed is zero.

[0198] Furthermore, with engine 4 stopped and brake pedal 19 depressed, the vehicle speed decreases relatively rapidly. In this situation, the coordinated regeneration flag becomes 1, initiating coordinated regeneration control. Full braking force is achieved through coordination between motor 5 and friction braking system 3, while motor 5 generates electricity simultaneously.

[0199] Subsequently, at time t1, suppose the driver operates the steering wheel 110. Due to this operation, it is determined that a request to restart the engine 4 has been made. Based on this determination, the steering angle flag becomes 1, and the braking system switches from coordinated braking based on the motor 5 and the friction braking system 3 to braking based solely on the friction braking system 3 (first process).

[0200] Afterwards, the braking switch is completed at time t2. Due to this, the restart flag becomes 1. With the restart flag set to 1, the engagement of clutch 6 (K0) begins, power is received from motor 5, and the engine speed begins to increase (second process). As the engine speed increases, the motor speed continuously decreases.

[0201] Subsequently, when the motor speed is lower than the second threshold at time t3, the K1 clutch 8d is engaged. By engaging the K1 clutch 8d, the motor speed increases and remains above the second threshold.

[0202] Here, from the relationship between time t2 and time t3, it can be seen that in this embodiment, the sliding of clutch 8d of K1 occurs after the switch to braking based solely on friction braking system 3 is completed.

[0203] As with conventional configurations, if the timing for slipping the K1 clutch 8d is not correlated with the timing for switching the brake, there is a possibility that the K1 clutch 8d may slip before the brake switching is completed. In this case, since the regenerative operation is performed while the power transmission between the motor 5 and the rear wheel 2R is suppressed, the output torque of the motor 5 (regenerative braking torque) cannot be sufficiently transmitted to the rear wheel 2R, and there is a possibility that gear disengagement (out of gear) may occur.

[0204] In this embodiment, the K1 clutch 8d is allowed to slip after the braking switch is completed. Therefore, when the regenerative braking torque is no longer applied (for example, when the regenerative braking torque is reduced to approximately zero), the K1 clutch 8d begins to slip. This prevents gear disengagement from occurring.

[0205] Subsequently, if the engine speed and the motor speed are the same at time t4, the controller 20 restarts the engine 4. Then, the controller 20 restarts the engine 4 by resuming fuel injection (third process).

[0206] (Regarding the coordination between brake switching and engine restart)

[0207] As explained above, according to this embodiment, during the deceleration of the vehicle 1 in which the friction braking system 3 distributes braking force to the rear wheels 2R, the motor 5 performs a regenerative operation. This control is based on coordinated regenerative control between the friction braking system 3 and the motor 5. Through coordinated regenerative control, the regenerative energy stored in the high-voltage battery 9 increases. The regenerative braking torque based on the motor 5 is applied to the rear wheels 2R, which serve as drive wheels. The friction braking system 3 takes into account the regenerative braking torque applied to the rear wheels 2R and distributes braking force to them. As a result, the braking applied to the vehicle 1 becomes braking corresponding to the driver's operation of the brake pedal 19. The controller 20 controls the distribution of braking force in a manner that achieves the desired braking (braking corresponding to the operation of the brake pedal 19) through regenerative braking torque and braking force.

[0208] Here, as Figure 6 As illustrated in the example of the relationship between steps S52 and S55, when the start of engine 4 is requested in the coordinated regenerative control, the controller 20 increases the output speed of engine 4 after the transition from braking based on coordinated regenerative control to braking based solely on friction braking system 3 is completed.

[0209] Therefore, as Figure 7As illustrated at time t2, the braking switch is completed when the engine speed adjustment begins. As a result, the impact of the output speed adjustment on the coordinated regenerative control and the braking switch that begins from the coordinated regenerative control can be suppressed.

[0210] In addition, such as Figure 6 As illustrated in step S61, there is a possibility that the engine speed may continue to be controlled through idle speed control and the like even after it has been adjusted. Therefore, by starting the engine 4 after the braking switch, it is possible to separate the processing related to output speed, such as idle speed control, from the processing related to braking switch. As a result, it is possible to suppress the influence of the idling speed control and other processing on the braking switch.

[0211] In addition, such as Figure 6 As illustrated in steps S57 and S58, the controller 20 causes the K1 clutch 8d to slip when predetermined conditions are met. By causing the K1 clutch 8d to slip, the rotational resistance of the motor 5 can be reduced. Therefore, the decrease in the output speed of the motor 5 can be suppressed.

[0212] Here, as is known in the past, if there is no correlation between the timing of slipping the K1 clutch 8d and the timing of switching to braking based solely on the friction braking system 3 (for example, if both processes start simultaneously), there is a possibility that the K1 clutch 8d may slip before the braking switch is completed.

[0213] In this situation, since the regenerative action is performed while the power transmission between the motor 5 and the rear wheel 2R is suppressed, the regenerative braking torque supplied by the motor 5 cannot be fully transmitted to the rear wheel 2R, and there is a possibility that the gears will disengage.

[0214] In this embodiment, such as Figure 6 The relationship between steps S52 and S58, and Figure 7 As illustrated by the relationship between time t2 and time t3, after the braking switch ends, clutch 8d of K1 is allowed to slip. Therefore, clutch 8d of K1 can begin to slip even when the regenerative braking torque has been applied (e.g., when the regenerative braking torque has been reduced to approximately zero). Thus, it is possible to suppress the occurrence of gear disengagement.

[0215] In addition, by conducting Figure 6 The idle speed control illustrated in step S61 can maintain the output speed of the engine 4 and the electric motor 5 at or above the idle speed after the engine 4 is restarted. Therefore, when an acceleration request is made to the car 1, such as when the brake pedal 19 is pressed and the accelerator pedal 18 is pressed, the car 1 can accelerate smoothly.

[0216] In addition, such as Figure 4 Step S23 and Figure 5 As illustrated in step S44, when the steering wheel 110 is operated during deceleration while the brake pedal 19 is depressed (in other words, during coordinated regeneration control), the controller 20 performs the first, second, and third processes described above. Therefore, for example, when the brake pedal 19 is depressed and the car 1 enters a curve, the engine 4 can be smoothly restarted without problems such as gear disengagement. Thus, compared to conventional hybrid vehicles, the so-called "slow in, fast out" can be achieved more smoothly. This improves the maneuverability of the hybrid vehicle.

[0217] In addition, such as Figure 4 Step S23 and Figure 5 As illustrated in step S44, when the controller 20 operates the A / C switch 71 during deceleration when the brake pedal 19 is depressed (in other words, during coordinated regeneration control execution), it performs the first, second, and third processes described above. Therefore, for example, if it is desired to drive the air conditioner 72 when the brake pedal 19 is depressed, the engine 4 can be restarted smoothly without causing problems such as gear disengagement. This suppresses engine restart shock. Consequently, the ride comfort of the hybrid vehicle can be improved.

Claims

1. A control device for a hybrid vehicle, the hybrid vehicle comprising: The engine generates the driving force for the vehicle; An electric motor can perform both power-driven and regenerative actions. The first clutch is clamped between the engine and the motor, and switches between a connected state that engages the engine and the motor and a disengaged state that releases the engagement of the engine and the motor. as well as The axle is sandwiched between the motor and the drive wheel of the vehicle. The control device for the hybrid vehicle is characterized by having: The second clutch is located between the motor and the axle, and switches between a connected state that engages the motor and the axle and a disengaged state that releases the engagement between the motor and the axle. A hydraulic friction braking system distributes braking force to the drive wheels according to the driver's operation of the brake pedal; as well as The control mechanism is capable of performing coordinated regenerative control when the first clutch is disengaged. This coordinated regenerative control refers to controlling braking during vehicle deceleration when the brake pedal is operated, by coordinating the distribution of braking force by the friction braking system with the regenerative braking torque supplied to the drive wheels through the regenerative action of the motor. When the control mechanism requests engine start-up during the coordinated regeneration control, it performs the following process: The first process involves transitioning from braking based on the coordinated regenerative control to braking based solely on the friction braking system; After the transition to braking based solely on the friction braking system is completed, a second process begins, initiating the engagement of the first clutch and causing the motor to perform either the power operation or the regenerative operation, thereby increasing the output speed of the engine. as well as After the first clutch engages, and the engine's output speed rises to match the motor's output speed, a third process restarts the engine. The second clutch is engaged when the coordinated regeneration control is executed. In the second process, after the engagement of the first clutch begins, the control mechanism causes the second clutch to slip when the output speed of the motor decreases to less than a predetermined speed.

2. The control device for a hybrid vehicle as described in claim 1, characterized in that, In the third process, after aligning the output speed of the engine with the output speed of the motor, the control mechanism releases the second clutch or causes the second clutch to slip when the output speeds of the engine and the motor decrease to a level lower than the specified idle speed, and controls the engine in such a manner that the output speed rises above the idle speed.

3. The control device for a hybrid vehicle as described in claim 1, characterized in that, When the steering angle exceeds a predetermined value during the coordinated regeneration control, the control mechanism determines that it has requested the engine to start.

4. The control device for a hybrid vehicle as described in claim 1, characterized in that, When the air conditioning switch accepts an on operation during the coordinated regeneration control, the control mechanism determines that it has requested the engine to start.

Images