Hybrid vehicle and hybrid vehicle control method

Abstract

To provide a hybrid vehicle capable of speeding up the starting of an engine, and a method of controlling the hybrid vehicle.SOLUTION: A hybrid vehicle is equipped with an engine that drives driving wheels, an engine starting motor that starts the engine, a driving motor that drives the driving wheels, and a clutch that couples or separates the engine and the driving motor. The hybrid vehicle is further equipped with a control device, which, according to a driving state, transmits driving force of at least one of the engine and the driving motor to the driving wheels, and controls the starting of the engine with the engine starting motor and the driving motor by coupling the engine and the driving motor with the clutch, when starting the engine.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a hybrid vehicle and a method for controlling a hybrid vehicle. [Background technology]

[0002] Patent Document 1 discloses that after the engine is started by an engine start motor, the engine and a drive motor are connected via a clutch, and the driving forces of the engine and the drive motor are transmitted to the drive wheels. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-071815 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the invention described in Patent Document 1, the engine is started only by the engine starting motor, which may result in a delay in starting the engine.

[0005] The present invention has been made in view of the above problems, and has an object to provide a hybrid vehicle and a control method for a hybrid vehicle that can speed up engine start-up. [Means for solving the problem]

[0006] According to one aspect of the present invention, there is provided a hybrid vehicle including an engine that drives drive wheels, an engine start motor that starts the engine, a drive motor that drives the drive wheels, and a clutch that connects or disconnects the engine and the drive motor, and in which driving force of at least one of the engine and the drive motor is transmitted to the drive wheels depending on the driving state, and the hybrid vehicle further includes a control device that, when starting the engine, connects the engine and the drive motor with the clutch, thereby controlling the start of the engine to be performed by the engine start motor and the drive motor. When the magnitude of the acceleration request is equal to or greater than a predetermined threshold, the control device completes the start of the engine with the clutch engaged, and when the magnitude of the acceleration request is less than the predetermined threshold, the control device completes the start of the engine with the clutch released. A hybrid vehicle is provided.

[0007] According to another aspect of the present invention, there is provided a method for controlling a hybrid vehicle that includes an engine that drives drive wheels, an engine start motor that starts the engine, a drive motor that drives the drive wheels, and a clutch that connects or disconnects the engine and the drive motor, and that transmits driving force from at least one of the engine and the drive motor to the drive wheels depending on an operating state, the method including the step of controlling, when starting the engine, to connect the engine and the drive motor by the clutch so that the engine is started by the engine start motor and the drive motor. When the magnitude of the acceleration request is equal to or greater than a predetermined threshold, the engine start is completed with the clutch engaged, and when the magnitude of the acceleration request is less than the predetermined threshold, the engine start is completed with the clutch released. A method for controlling a hybrid vehicle is provided. [Effects of the Invention]

[0008] According to these aspects, the engine can be started more quickly. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a hybrid vehicle. [Figure 2] FIG. 2 is a block diagram showing a controller and main components connected to the controller. [Figure 3] 10 is a flowchart showing the engine motor starting process. [Figure 4]4 is a time chart illustrating engine starting by the engine starting motor and the drive motor. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention (hereinafter referred to as the present embodiment) will be described with reference to the accompanying drawings.

[0011] (Hybrid vehicle configuration) First, a hybrid vehicle 100 according to this embodiment will be described with reference to FIG.

[0012] Fig. 1 is a schematic diagram of a hybrid vehicle 100. As shown in Fig. 1, the hybrid vehicle 100 includes an engine ENG, a rotating electric machine MG1 as an engine start motor, a clutch CL, a rotating electric machine MG2 as a drive motor, a battery BAT as an electricity storage device, a torque converter TC, a transmission TM, drive wheels DW, a mechanical oil pump MP, an electric oil pump EP, a hydraulic control circuit 1, a controller 2 as a control device, and various sensors 3. The hybrid vehicle 100 transmits the driving force of at least one of the engine ENG and the rotating electric machine MG2 to the drive wheels DW depending on the driving conditions.

[0013] The engine ENG is one of the drive sources that drives the drive wheels DW. The drive force of the engine ENG is transmitted to the drive wheels DW via the clutch CL, the torque converter TC, and the transmission TM. In other words, the clutch CL, the torque converter TC, and the transmission TM are provided in a power transmission path that connects the engine ENG and the drive wheels DW.

[0014] The rotating electric machine MG1 is a motor for starting the engine ENG. The rotating electric machine MG1 is provided downstream of the engine ENG in the power transmission path. Specifically, the rotating electric machine MG1 is provided between the engine ENG and the clutch CL. When the rotating electric machine MG1 is driven by the engine ENG or when regenerative control is being performed, the rotating electric machine MG1 functions as a generator. The electric energy generated by the rotating electric machine MG1 is charged into the battery BAT. Note that the rotating electric machine MG1 does not necessarily have to be provided in the power transmission path.

[0015] The clutch CL connects or disconnects the engine ENG and the rotating electric machine MG2 to connect or disconnect the transmission of power. The clutch CL is provided downstream of the engine ENG (downstream of the rotating electric machine MG1) in the power transmission path. Specifically, the clutch CL is provided between the engine ENG and the rotating electric machine MG2. When the clutch CL is engaged, that is, when the engine ENG and the rotating electric machine MG2 are connected by the clutch CL, the driving force of the engine ENG is transmitted to the drive wheels DW via the torque converter TC and the transmission TM.

[0016] The clutch CL has a pair of engagement elements PL1, PL2. One engagement element PL1 rotates integrally with the output shaft of the engine ENG and the rotating shaft of the rotating electric machine MG1, while the other engagement element PL2 rotates integrally with the rotating shaft of the rotating electric machine MG2 and the input shaft of the torque converter TC. The clutch CL is frictionally engaged by the engagement elements PL1 and PL2 coming into contact with each other.

[0017] The rotating electric machine MG2 is the other drive source that drives the drive wheels DW. The rotating electric machine MG2 drives the drive wheels DW using at least one of the electric energy generated by the rotating electric machine MG1 and the electric energy charged in the battery BAT. The rotating electric machine MG2 is provided downstream of the engine ENG in the power transmission path. Specifically, the rotating electric machine MG2 is provided between the clutch CL and the torque converter TC. The driving force of the rotating electric machine MG2 is transmitted to the drive wheels DW via the torque converter TC and the transmission TM. The rotating electric machine MG2 functions as a generator when driven by the engine ENG or when regenerative control is being performed. The rotating electric machine MG2 is configured so that its maximum output is greater than the maximum output of the rotating electric machine MG1.

[0018] The battery BAT is formed of, for example, a lithium ion secondary battery. Instead of the battery BAT, a capacitor or the like may be provided as a power storage device. The battery BAT is charged with electrical energy generated when the rotating electric machine MG1 is driven by the engine ENG and electrical energy generated when the rotating electric machines MG1 and MG2 are regeneratively controlled. The battery BAT supplies electrical energy for driving the rotating electric machines MG1 and MG2.

[0019] The torque converter TC is a power transmission device that transmits driving force from the engine ENG or the rotating electric machine MG2 to the transmission TM via oil as a fluid. The torque converter TC is provided downstream of the rotating electric machine MG2 in the power transmission path. Specifically, the torque converter TC is provided between the rotating electric machine MG2 and the transmission TM. The torque converter TC has a lock-up clutch LU.

[0020] When the lockup clutch LU is engaged, it directly connects the rotating electric machine MG2 and the drive wheels DW (specifically, the transmission TM). When the lockup clutch LU is engaged, that is, when the rotating electric machine MG2 and the transmission TM are connected by the lockup clutch LU, it is possible to increase the efficiency of power transmission of the driving force of the engine ENG or the rotating electric machine MG2 to the drive wheels DW.

[0021] The transmission TM changes the speed of the driving force of the engine ENG and the rotating electric machine MG2 transmitted from the torque converter TC and transmits it to the drive wheels DW. The transmission TM is provided downstream of the rotating electric machine MG2 in the power transmission path. Specifically, the transmission TM is provided between the torque converter TC and the drive wheels DW. The transmission TM may be a belt-type continuously variable transmission or a stepped transmission.

[0022] The mechanical oil pump MP pumps (supplies) oil to the hydraulic control circuit 1. The mechanical oil pump MP is driven by the driving force of the engine ENG.

[0023] The electric oil pump EP, together with the mechanical oil pump MP or independently, pressure-feeds (supplies) oil to the hydraulic control circuit 1. If the supply of oil from the mechanical oil pump MP to the hydraulic control circuit 1 is stopped or becomes insufficient, the electric oil pump EP temporarily supplies oil to the hydraulic control circuit 1 based on a drive request to make up for the shortage of oil. The electric oil pump EP is driven by a pump drive motor PM.

[0024] The hydraulic control circuit 1 is composed of multiple flow paths and multiple hydraulic control valves. The hydraulic control circuit 1 adjusts the pressure of oil supplied from the mechanical oil pump MP and the electric oil pump EP and supplies it to each part of the transmission TM. The hydraulic control circuit 1 also controls the hydraulic pressure of the clutch CL, lock-up clutch LU, etc. based on commands from the controller 2.

[0025] The controller 2 is configured by a microcomputer equipped with a central processing unit (CPU), read-only memory (ROM), random access memory (RAM), and input / output interfaces (I / O interfaces) 21, 22 (see FIG. 2). The controller 2 can also be configured by multiple microcomputers. Specifically, the controller 2 can also be configured by an ATCU that controls the transmission TM, an SCU that controls the shift range, an ECU that controls the engine ENG, etc.

[0026] The controller 2 controls the engine ENG, the hydraulic control circuit 1, the rotating electric machine MG1, and the rotating electric machine MG2 based on signals output from various sensors 3, etc. The controller 2 drives the hybrid vehicle 100 by selecting one of the following modes: an electric driving mode in which the engine ENG is stopped and the clutch CL is released so that the vehicle drives using the driving force of the rotating electric machine MG2; a series hybrid driving mode in which the driving force of the engine ENG is used to cause the rotating electric machine MG1 to generate electricity and the clutch CL is released so that the vehicle drives using the driving force of the rotating electric machine MG2; and a parallel hybrid driving mode in which the clutch CL is engaged so that the vehicle drives using the driving force of the engine ENG and the rotating electric machine MG2. Details of the controller 2 will be described later.

[0027] The various sensors 3 are sensors that detect various parameters and include an accelerator opening detection sensor 31 that detects an accelerator opening (i.e., an acceleration request by the driver), a torque detection sensor 32 that detects the output torque of the engine ENG, a first rotation speed detection sensor 33 that detects the rotation speed of the rotating electric machine MG1, a second rotation speed detection sensor 34 that detects the rotation speed of the rotating electric machine MG2, and a capacity detection sensor (oil pressure sensor) 35 that detects the capacity of the lock-up clutch LU.

[0028] (Controller configuration) Next, the controller 2 will be described with reference to FIG.

[0029] FIG. 2 is a block diagram showing the controller 2 and the main components connected to the controller 2. As shown in FIG.

[0030] 2, the controller 2 includes an input interface 21, an output interface 22, a memory unit 23, an engine start motor control unit 24, a drive motor control unit 25, a hydraulic control circuit control unit 26 (hereinafter simply referred to as the circuit control unit 26), a determination unit 27, and an engine control unit 28, which are electrically connected to one another. The engine start motor control unit 24, the drive motor control unit 25, the circuit control unit 26, the determination unit 27, and the engine control unit 28 are virtual units that represent the functions of the controller 2 for controlling the hybrid vehicle 100, and do not represent physical entities.

[0031] The input interface 21 receives output signals from the various sensors 3 .

[0032] The storage unit 23 is a memory for temporarily storing output signals from the various sensors 3. The storage unit 23 also stores processing programs and algorithm programs executed by the engine start motor control unit 24, the drive motor control unit 25, and the circuit control unit 26. The storage unit 23 also stores a first predetermined accelerator opening, a second predetermined accelerator opening as a predetermined threshold, and a predetermined clutch capacity used in the engine / motor start process. Details of the first predetermined accelerator opening, the second predetermined accelerator opening, and the predetermined clutch capacity will be described later in the engine / motor start process. In this embodiment, the storage unit 23 is built into the controller 2, but is not limited to this. For example, the storage unit 23 may be provided separately from the controller 2.

[0033] The engine start motor control command generated by processing of the engine start motor control unit 24, the drive motor control command generated by processing of the drive motor control unit 25, and the circuit control command generated by processing of the circuit control unit 26 are output to the rotating electric machine MG1, the rotating electric machine MG2, and the hydraulic control circuit 1, respectively, via the output interface 22.

[0034] The engine starting motor control unit 24 generates an engine starting motor control command based on the output signals output from the various sensors 3, and outputs the generated engine starting motor control command to the rotating electric machine MG1 via the output interface 22.

[0035] The drive motor control unit 25 generates a drive motor control command based on the output signals output from the various sensors 3, and outputs the generated drive motor control command to the rotating electric machine MG2 via the output interface 22.

[0036] The circuit control unit 26 generates a circuit control command based on the output signals output from the various sensors 3, and outputs the generated circuit control command to the hydraulic control circuit 1 via the output interface 22.

[0037] The circuit control unit 26 also has a clutch control module 261, a lockup clutch control module 262, and a transmission control module 263. The clutch control module 261 generates a clutch control command based on output signals output from the various sensors 3, and outputs the generated clutch control command to the hydraulic control circuit 1 via the output interface 22. The lockup clutch control module 262 generates a lockup clutch control command based on output signals output from the various sensors 3, and outputs the generated lockup clutch control command to the hydraulic control circuit 1 via the output interface 22. The transmission control module 263 generates a transmission control command based on output signals output from other various sensors (not shown), and outputs the generated transmission control command to the hydraulic control circuit 1 via the output interface 22.

[0038] The determination unit 27 performs various determinations based on the output signals output from the various sensors 3, and outputs the results of the various determinations to the engine start motor control unit 24, the drive motor control unit 25, or the circuit control unit .

[0039] The engine control unit 28 generates an engine control command based on the output signals output from the various sensors 3, and outputs the generated engine control command to the engine ENG via the output interface 22.

[0040] Details of the engine start motor control unit 24, the drive motor control unit 25, the circuit control unit 26 (specifically, the clutch control module 261 and the lock-up clutch control module 262), the determination unit 27 and the engine control unit 28 will be described later in the engine / motor start processing section.

[0041] (Engine and motor start processing) Next, the engine / motor starting process will be described in detail with reference to FIGS.

[0042] Fig. 3 is a flowchart showing the engine / motor start process, Fig. 4 is a time chart illustrating engine start by the rotary electric machine MG1 and the rotary electric machine MG2.

[0043] Fig. 4(a) shows the change in output torque of each element over time. Specifically, in Fig. 4(a), MG1_TRQ, ENG_TRQ, CL_TRQ, MG2_TRQ, and LU_TRQ respectively show the change in output torque of the rotating electric machine MG1 over time, the change in output torque of the engine ENG over time, the change in clutch capacity transmission torque of the clutch CL over time, the change in output torque of the rotating electric machine MG2 over time, and the change in transmission torque of the lock-up clutch LU over time.

[0044] Fig. 4(b) shows the change in the rotation speed of each element over time. Specifically, in Fig. 4(b), ENG_REV, MG2_REV, and TBN_REV respectively show the change in the rotation speed of the engine ENG over time, the change in the rotation speed of the rotating electrical machine MG2 over time, and the change in the rotation speed of the turbine (not shown) over time.

[0045] When the driver turns the ignition switch (not shown) of the hybrid vehicle 100 from OFF to ON, the engine / motor start process begins.

[0046] 3, first, in step S101, accelerator opening detection sensor 31 detects the accelerator opening, and then outputs the detected accelerator opening as an output signal to determination unit 27 of controller 2 via input interface 21, and the process proceeds to step S102.

[0047] Next, in step S102, determination unit 27 determines whether the detected accelerator opening output from accelerator opening detection sensor 31 is equal to or greater than a first predetermined accelerator opening stored in memory unit 23 (i.e., whether or not there is a request to start the engine). If the detected accelerator opening is equal to or greater than the first predetermined accelerator opening (Yes), that is, if there is a request to start the engine, the process proceeds to step S103. On the other hand, if the detected accelerator opening is less than the first predetermined accelerator opening (No), that is, if there is no request to start the engine, the process proceeds to step S104.

[0048] Next, in step S104, based on the result that there is no request for engine start, the drive motor control unit 25 of the controller 2 controls the drive of the rotary electric machine MG2 so that the rotation speed of the rotary electric machine MG2 corresponds to the accelerator opening, and ends this process. In this case, the motor is started without starting the engine.

[0049] Meanwhile, in step S103, the engine start motor control unit 24 of the controller 2 controls the rotating electric machine MG1 to be driven, and the process proceeds to step S105. Specifically, in step S103, the engine start motor control unit 24 generates an engine start motor control command that maximizes the output torque MG1_TRQ of the rotating electric machine MG1 based on the result that there is a request to start the engine. Then, the engine start motor control unit 24 outputs the generated engine start motor control command to the rotating electric machine MG1 via the output interface 22.

[0050] 4(a), before the engine ENG is started, the rotating electric machine MG1 is driven so that its output torque MG1_TRQ becomes maximum based on an engine start motor control command output from the engine start motor control unit 24. The output torque MG1_TRQ of the rotating electric machine MG1 is used to start the engine ENG.

[0051] Next, in step S105, determination unit 27 determines whether the detected accelerator opening is equal to or greater than the second predetermined accelerator opening stored in memory unit 23 (i.e., whether engine start assistance by the rotating electric machine MG2 is required). If the detected accelerator opening is equal to or greater than the second predetermined accelerator opening (Yes), that is, if engine start assistance by the rotating electric machine MG2 is required, the process proceeds to step S106. On the other hand, if the detected accelerator opening is less than the second predetermined accelerator opening (No), that is, if engine start assistance by the rotating electric machine MG2 is not required, the process skips step S106 to step S110 and proceeds to step S111.

[0052] Next, in step S106, capacity detection sensor 35 detects the capacity of lock-up clutch LU based on the result that engine start assistance by rotating electric machine MG2 is necessary. Capacity detection sensor 35 then outputs the detected lock-up clutch capacity as an output signal to determination unit 27 via input interface 21, and the process proceeds to step S107.

[0053] Next, in step S107, determination unit 27 determines whether the output detected lockup clutch capacity is the lockup clutch capacity when lockup clutch LU is in a slip state (i.e., whether lockup clutch LU is in a slip state). If the detected lockup clutch capacity is the lockup clutch capacity when lockup clutch LU is in a slip state (if Yes), that is, if lockup clutch LU is in a slip state, the process proceeds to step S108.

[0054] In this way, when the lock-up clutch LU is in a slip state, each step (specifically, step S108 and step S110) for assisting engine start by the rotating electric machine MG2 is executed, so that when assisting engine start by the rotating electric machine MG2, the output torque MG2_TRQ of the rotating electric machine MG2 can be prevented from being transmitted to the drive wheels DW via the transmission TM.

[0055] On the other hand, if the detected lockup clutch capacity is not the lockup clutch capacity when the lockup clutch LU is in a slip state (No), that is, if the lockup clutch LU is not in a slip state, the process proceeds to step S109.

[0056] Next, in step S108, the circuit control unit 26 and the hydraulic control circuit 1 control the capacity of the clutch CL, and the process proceeds to step S110. Specifically, in step S108, the clutch control module 261 generates a clutch capacity control command for changing the capacity of the clutch CL to a predetermined clutch capacity stored in the storage unit 23, based on the result that the lock-up clutch LU is in a slip state. Then, the clutch control module 261 outputs the generated clutch capacity control command to the hydraulic control circuit 1 via the output interface 22.

[0057] The hydraulic control circuit 1 then adjusts the pressure of oil and supplies it to the clutch CL so that the capacity of the clutch CL becomes a predetermined clutch capacity, based on the clutch capacity control command output from the clutch control module 261. This allows the engine ENG and the rotating electrical machine MG2 to be connected by the clutch CL with a given capacity.

[0058] Next, in step S110, the drive motor control unit 25 of the controller 2 controls the rotating electric machine MG2 to be driven, and the process proceeds to step S111. Specifically, in step S110, the drive motor control unit 25 generates a drive motor control command that maximizes the output torque MG2_TRQ of the rotating electric machine MG2. The drive motor control unit 25 then outputs the generated drive motor control command to the rotating electric machine MG2 via the output interface 22.

[0059] As shown in FIG. 4(a), the rotary electric machine MG2 is driven based on a drive motor control command output from the drive motor control unit 25 so that its output torque MG2_TRQ becomes maximum.

[0060] In this case, as shown in Fig. 4(a), at time T1, the engine ENG and the rotating electric machine MG2 are connected by the clutch CL, and of the output torque MG2_TRQ of the rotating electric machine MG2, only the transmission torque CL_TRQ corresponding to the clutch capacity of the clutch CL is used as an assist torque to start the engine ENG. As a result, in addition to the output torque MG1_TRQ of the rotating electric machine MG1, part of the output torque MG2_TRQ of the rotating electric machine MG2 (i.e., the transmission torque CL_TRQ of the clutch CL) is used to start the engine ENG, so the time T1 required to start the engine can be shortened. As a result, the engine ENG can be started more quickly.

[0061] On the other hand, in step S109, circuit control unit 26 and hydraulic control circuit 1 control lockup clutch LU to reduce its capacity, and then return to step S106. Specifically, lockup clutch control module 262 of circuit control unit 26 generates a lockup clutch control command to reduce the capacity of lockup clutch LU based on the result that lockup clutch LU is not in a slip state. Then, lockup clutch control module 262 outputs the generated lockup clutch control command to hydraulic control circuit 1 via output interface 22.

[0062] Based on a lock-up clutch control command output from the lock-up clutch control module 262, the hydraulic control circuit 1 adjusts the pressure of oil and supplies it to the lock-up clutch LU so that the capacity of the lock-up clutch LU decreases.

[0063] Next, in step S111, the torque detection sensor 32 detects the output torque ENG_TRQ of the engine ENG. Then, the torque detection sensor 32 outputs the detected output torque ENG_TRQ of the engine ENG as an output signal to the determination unit 27 via the input interface 21, and the process proceeds to step S112.

[0064] Next, in step S112, the determination unit 27 determines whether the output torque ENG_TRQ of the engine ENG output from the torque detection sensor 32 exceeds zero (i.e., whether the starting of the engine ENG has been completed). If the output torque ENG_TRQ of the engine ENG exceeds zero (if Yes) in a time period after the timing t1 shown in FIG. 4(a), that is, if the starting of the engine ENG has been completed, the process proceeds to step S113. On the other hand, if the output torque ENG_TRQ of the engine ENG is zero (if No) at the time T1 shown in FIG. 4(a), that is, if the starting of the engine ENG has not been completed, the process returns to step S103.

[0065] Next, in step S113, the first rotation speed detection sensor 33 and the second rotation speed detection sensor 34 respectively detect the rotation speed of the rotating electric machine MG1 (i.e., the rotation speed ENG_REV of the engine ENG) and the rotation speed MG2_REV of the rotating electric machine MG2. Then, the first rotation speed detection sensor 33 and the second rotation speed detection sensor 34 output the detected rotation speed ENG_REV of the engine ENG and the rotation speed MG2_REV of the rotating electric machine MG2 to the determination unit 27 via the input interface 21, and the process proceeds to step S114.

[0066] Next, in step S114, the judgment unit 27 judges whether the rotation speed ENG_REV of the engine ENG and the rotation speed MG2_REV of the rotating electric machine MG2 output from the first rotation speed detection sensor 33 and the second rotation speed detection sensor 34, respectively, match (i.e., whether the rotation of the engine ENG and the rotation of the rotating electric machine MG2 are synchronized).

[0067] Then, if the rotation speed ENG_REV of the engine ENG and the rotation speed MG2_REV of the rotating electric machine MG2 match (Yes) in the time period after timing t2 shown in Figure 4(b), that is, if the rotation of the engine ENG and the rotation of the rotating electric machine MG2 are synchronized, proceed to step S115.

[0068] On the other hand, if the rotation speed ENG_REV of the engine ENG and the rotation speed MG2_REV of the rotating electric machine MG2 do not match (No) during the time period before timing t2 shown in Figure 4(b), that is, if the rotation of the engine ENG and the rotation of the rotating electric machine MG2 are not synchronized, proceed to step S116.

[0069] Next, in step S116, the engine control unit 28 of the controller 2 drives and controls the engine ENG so that its rotation speed matches the rotation speed of the rotating electric machine MG2, and then returns to step S113. Specifically, in step S116, the engine control unit 28 generates an engine control command such that the rotation speed ENG_REV of the engine ENG matches the rotation speed MG2_REV of the rotating electric machine MG2, based on the result that the rotation of the engine ENG and the rotation of the rotating electric machine MG2 are not synchronized. Then, the engine control unit 28 outputs the generated engine control command to the engine ENG via the output interface 22.

[0070] The engine ENG is driven based on an engine control command output from the engine control unit 28 so that the rotation speed ENG_REV thereof becomes the rotation speed MG2_REV of the rotary electric machine MG2.

[0071] On the other hand, in step S115, the circuit control unit 26 and the hydraulic control circuit 1 control the capacity of the clutch CL to be maximum (i.e., the clutch CL is in an engaged state), and then proceed to step S117. Specifically, in step S115, the clutch control module 261 generates a clutch capacity control command to maximize the capacity of the clutch CL based on the result that the rotation of the engine ENG and the rotation of the rotating electric machine MG2 are synchronized. Then, the clutch control module 261 outputs the generated clutch capacity control command to the hydraulic control circuit 1 via the output interface 22.

[0072] Then, based on the clutch capacity control command output from the clutch control module 261, the hydraulic control circuit 1 adjusts the pressure of oil and supplies it to the clutch CL so that the capacity of the clutch CL is maximized. As a result, the engine ENG and the rotating electric machine MG2 are coupled together by the clutch CL. Therefore, after the engine ENG and the rotating electric machine MG2 are coupled together by the clutch CL (i.e., during the time period after timing t3 shown in FIG. 4(a)), the output torque ENG_TRQ of the engine ENG can be transmitted to the rotating electric machine MG2 as the transmission torque CL_TRQ of the clutch CL.

[0073] Next, in step S117, the engine start motor control unit 24 controls the rotating electric machine MG1 to stop driving, and proceeds to step S118. Specifically, in step S117, the engine start motor control unit 24 generates an engine start motor control command such that the output torque MG1_TRQ of the rotating electric machine MG1 becomes zero. Then, the engine start motor control unit 24 outputs the generated engine start motor control command to the rotating electric machine MG1 via the output interface 22.

[0074] Then, based on the engine start motor control command output from the engine start motor control unit 24, the rotary electric machine MG1 is stopped so that the output torque MG1_TRQ becomes zero.

[0075] Next, in step S118, the circuit control unit 26 and the hydraulic control circuit 1 control the capacity of the lockup clutch LU to be maximum (i.e., the lockup clutch LU is in an engaged state), and then end this process. Specifically, in step S118, the lockup clutch control module 262 generates a lockup clutch capacity control command that maximizes the capacity of the lockup clutch LU. The lockup clutch control module 262 then outputs the generated lockup clutch capacity control command to the hydraulic control circuit 1 via the output interface 22.

[0076] Then, based on the lockup clutch capacity control command output from the lockup clutch control module 262, the hydraulic control circuit 1 adjusts the pressure of oil and supplies it to the lockup clutch LU so that the capacity of the lockup clutch LU is maximized. As a result, the rotating electric machine MG2 and the transmission TM are connected by the lockup clutch LU. Also, as described above, the engine ENG and the rotating electric machine MG2 are connected by the clutch CL. Therefore, after the rotating electric machine MG2 and the transmission TM are connected by the lockup clutch LU (i.e., during the time period after timing t4 shown in FIG. 4(a)), the sum of the output torque ENG_TRQ of the engine ENG and the output torque MG2_TRQ of the rotating electric machine MG2 can be transmitted to the drive wheels DW via the transmission TM as the transmission torque LU_TRQ of the lockup clutch LU.

[0077] Furthermore, after the rotating electric machine MG2 and the transmission TM are connected by the lock-up clutch LU (i.e., the time period after timing t4 shown in Figure 4(b)), the rotation speed ENG_REV of the engine ENG, the rotation speed MG2_REV of the rotating electric machine MG2, and the rotation speed of the turbine TBN_REV are the same.

[0078] (Action and effect) Next, the main effects of this embodiment will be described.

[0079] (1) The hybrid vehicle 100 according to this embodiment is equipped with an engine ENG that drives the drive wheels DW, a rotating electric machine MG1 that starts the engine ENG, a rotating electric machine MG2 that drives the drive wheels DW, and a clutch CL that connects or disconnects the engine ENG and the rotating electric machine MG2, and transmits the driving force of at least one of the engine ENG and the rotating electric machine MG2 to the drive wheels DW depending on the driving state. When starting the engine ENG, the hybrid vehicle 100 further includes a controller 2 (control device) that controls the starting of the engine ENG to be performed by the rotating electric machine MG1 and the rotating electric machine MG2 by connecting the engine ENG and the rotating electric machine MG2 with the clutch CL.

[0080] (4) The control method for the hybrid vehicle 100 according to this embodiment is a control method for the hybrid vehicle 100, which is equipped with an engine ENG that drives the drive wheels DW, a rotating electric machine MG1 that starts the engine ENG, a rotating electric machine MG2 that drives the drive wheels DW, and a clutch CL that connects or disconnects the engine ENG and the rotating electric machine MG2, and transmits the driving force of at least one of the engine ENG and the rotating electric machine MG2 to the drive wheels DW depending on the driving state. When starting the engine ENG, the method includes a step of controlling the starting of the engine ENG to be performed by the rotating electric machine MG1 and the rotating electric machine MG2 by connecting the engine ENG and the rotating electric machine MG2 by the clutch CL.

[0081] According to these configurations, the engine ENG is started using the output torque of the rotary electric machine MG2 in addition to the output torque of the rotary electric machine MG1, so that the time T1 required to start the engine can be shortened, and as a result, the engine ENG can be started more quickly.

[0082] (2) The hybrid vehicle 100 further includes a torque converter TC having a lock-up clutch UL, which is provided between the rotating electric machine MG2 and the drive wheels DW, and the controller 2 (control device) controls the lock-up clutch LU to be in a slip state when the engine ENG is started by the rotating electric machine MG1 and the rotating electric machine MG2.

[0083] According to this configuration, when the rotary electric machine MG2 assists in starting the engine, the output torque of the rotary electric machine MG2 can be prevented from being transmitted to the drive wheels DW via the transmission TM, thereby preventing unintended movement of the drive wheels DW.

[0084] (3) When the detected accelerator opening (magnitude of acceleration request) is equal to or greater than a second predetermined accelerator opening (predetermined threshold), the controller 2 (control device) controls the clutch CL to connect the engine ENG and the rotating electric machine MG2 by the clutch CL.

[0085] According to this configuration, by connecting the engine ENG and the rotary electric machine MG2 by the clutch CL as needed, the engine ENG can be started by the rotary electric machines MG1 and MG2.

[0086] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above embodiments.

[0087] (Variation) In the above-described embodiment, the processing of the hybrid vehicle 100 has been described as an example of when the hybrid vehicle 100 starts moving, but this is not limited to this and may be applied, for example, when the engine ENG accelerates from a stopped state. [Explanation of symbols]

[0088] 2 Controller (control device) 100 Hybrid Vehicles CL Clutch DW drive wheel LU lock-up clutch TC torque converter ENG Engine MG1 Engine Start Motor MG2 drive motor

Claims

1. An engine that drives the drive wheels; an engine starting motor that starts the engine; a drive motor that drives the drive wheels; a clutch that connects or disconnects the engine and the drive motor, A hybrid vehicle that transmits driving force of at least one of the engine and the drive motor to the drive wheels depending on a driving state, a control device that controls the engine to be started by the engine start motor and the drive motor by connecting the engine and the drive motor by the clutch when starting the engine, When the magnitude of the acceleration request is equal to or greater than a predetermined threshold, the control device completes the start of the engine with the clutch engaged, When the magnitude of the acceleration request is less than the predetermined threshold, the control device completes the start of the engine with the clutch released. Hybrid vehicle.

2. 2. The hybrid vehicle according to claim 1, a torque converter provided between the drive motor and the drive wheels and having a lock-up clutch; the control device controls the lock-up clutch to be in a slip state when starting the engine by the engine start motor and the drive motor. Hybrid vehicle.

3. An engine that drives the drive wheels; an engine starting motor that starts the engine; a drive motor that drives the drive wheels; a clutch that connects or disconnects the engine and the drive motor, A control method for a hybrid vehicle that transmits driving force of at least one of the engine and the drive motor to the drive wheels depending on a driving state, comprising: a step of controlling, when starting the engine, the engine and the drive motor to be connected by the clutch so that the engine is started by the engine start motor and the drive motor; When the magnitude of the acceleration request is equal to or greater than a predetermined threshold, the engine start is completed with the clutch engaged; When the magnitude of the acceleration request is less than the predetermined threshold, the engine start is completed with the clutch released. A method for controlling a hybrid vehicle.

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