JP2012091620A - Engine start control device of hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform engine start control according to driver's intention of acceleration.SOLUTION: An engine start control device includes an engine 1 and a motor 5 as driving sources, wherein the engine 1 and the motor 5 are connected through a clutch 6 which can change transmission torque capacity, and when starting the engine 1 into operation, cranking of the engine 1 is carried out by fastening the clutch 6 and by the driving force of the motor 5. When starting the engine 1 under stopping into operation by a result of driver's accelerator operation, and when the acceleration intent of the driver is large, the transmission torque capacity of the clutch 6 in cranking the engine 1 is enlarged compared to when the acceleration intent of the driver is small.

Description

  The present invention relates to engine start control of a hybrid vehicle that includes an engine and a motor as drive sources and is provided with a clutch therebetween.

  For example, Patent Document 1 includes an engine and a motor / generator as drive sources, and a first clutch capable of changing a transmission torque capacity is interposed between the engine and the motor / generator, thereby driving the motor / generator and the vehicle. A hybrid vehicle is disclosed in which a second clutch capable of changing a transmission torque capacity is interposed between the vehicle and a wheel.

  And in this patent document 1, the engine is stopped, the engine is started while traveling only by the driving force from the motor / generator, and the operation mode for traveling by the driving force of both the engine and the motor / generator is set. When there is a switch request, the second clutch is engaged by slip engagement by setting the transmission torque capacity of the second clutch to be equal to or less than the engine start motor / generator torque, and the fluctuation at the time of engine start is driven by the progress of the engagement of the first clutch. A technique is disclosed that enables torque to be transmitted to the drive wheel even during engine cranking while preventing transmission to the wheel.

JP2007-126091

  However, in Patent Document 1 described above, since the magnitude of the driver's intention to accelerate is not considered when the engine is started during traveling using only the driving force from the motor / generator, the driver's intention to accelerate When the engine speed is large, it is not always possible to quickly start the engine that satisfies the driver's request, and the driver may feel uncomfortable about the startability of the engine.

  The present invention includes an engine and a motor as drive sources, the engine and the motor are connected via a clutch capable of changing a transmission torque capacity, and the clutch is engaged when the engine is started. The present invention is applied to a hybrid vehicle that performs cranking of the engine by the driving force of the motor / generator. Then, when starting the engine that has been stopped due to the result of the accelerator operation by the driver, when the driver's intention to accelerate is larger, the engine is being cranked than when the driver's intention to accelerate is smaller. The clutch transmission torque capacity is increased.

  According to the present invention, when the driver's intention to accelerate is large, the engine can be started quickly, and the driver's intention to accelerate can be promptly met.

BRIEF DESCRIPTION OF THE DRAWINGS Structure explanatory drawing which shows one Example of the power train of the hybrid vehicle to which this invention is applied. Structure explanatory drawing which shows the modification of the power train of the hybrid vehicle to which this invention is applied. Structure explanatory drawing which shows the further modification of the power train of the hybrid vehicle to which this invention is applied. The block diagram which shows the control system of this power train. The timing chart which shows an example of operation | movement of each part at the time of starting the engine 1 stopped in 1st start mode. The timing chart which shows an example of operation | movement of each part at the time of starting the engine 1 stopped in 2nd start mode. The flowchart which shows the outline of the flow of control at the time of engine starting.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  First, a basic configuration of a hybrid vehicle to which the present invention is applied will be described. FIG. 1 shows a power train of a hybrid vehicle having a front engine / rear wheel drive (FR) type configuration as one embodiment of the present invention, wherein 1 is an engine and 2 is a drive wheel (rear wheel). The present invention is not limited to this FR format, and can be applied to other formats such as FF format or RR format.

  In the power train of the hybrid vehicle shown in FIG. 1, an automatic transmission 3 is arranged in tandem at the rear of the engine 1 in the vehicle front-rear direction in the same manner as a normal rear wheel drive vehicle, and from the engine 1 (crankshaft 1a). A motor / generator 5 is integrally provided on the shaft 4 that transmits the rotation to the input shaft 3 a of the automatic transmission 3.

  The motor / generator 5 is composed of a synchronous motor using a permanent magnet as a rotor, and acts as a motor (so-called “powering”) and also acts as a generator (so-called “regeneration”). As described above, it is located between the engine 1 and the automatic transmission 3. More specifically, a first clutch 6 is interposed between the motor / generator 5 and the engine 1, more specifically between the shaft 4 and the engine crankshaft 1 a, and the first clutch 6 is connected to the engine 1. The motor / generator 5 is detachably coupled.

  Here, the first clutch 6 has a configuration in which the transmission torque capacity can be continuously changed. For example, the first clutch 6 is normally closed so that the transmission torque capacity can be changed by continuously controlling the clutch hydraulic pressure with a proportional solenoid valve or the like. It consists of a dry type single plate clutch or a wet multi-plate clutch.

  Further, a second clutch 7 is interposed between the motor / generator 5 and the drive wheel 2, more specifically, between the shaft 4 and the transmission input shaft 3a. The second clutch 7 is connected to the motor. / The generator 5 and the automatic transmission 3 are detachably coupled.

  Similarly to the first clutch 6, the second clutch 7 is configured so that the transmission torque capacity can be continuously changed. For example, the transmission torque capacity can be changed by continuously controlling the clutch hydraulic pressure with a proportional solenoid valve. It consists of possible wet multi-plate clutch or dry single-plate clutch.

  The automatic transmission 3 selectively engages or releases a plurality of friction elements (such as clutches and brakes), and thus, by changing the engagement / release of these friction elements, the forward speed, the reverse speed, the reverse speed, etc. It is realized. That is, the automatic transmission 3 shifts the rotation input from the input shaft 3a at a gear ratio corresponding to the selected shift speed, and outputs it to the output shaft 3b. This output rotation is distributed and transmitted to the left and right drive wheels (rear wheels) 2 via the differential gear device 8. The automatic transmission 3 is not limited to the stepped type as described above, and may be a continuously variable transmission. The automatic transmission 3 has a P (parking) range and N (neutral) range as non-traveling ranges, and a D (drive) range and R (running ranges) as ranges selected by the driver via a select lever or the like. Reverse) range.

  In the power train described above, an electric vehicle traveling mode (EV mode) that travels using only the power of the motor / generator 5 as a power source, and a hybrid traveling mode (HEV) that travels while including the engine 1 together with the motor / generator 5 as a power source. Mode). For example, the EV mode is required at low loads and low vehicle speeds, including when starting from a stopped state. In this EV mode, power from the engine 1 is unnecessary, so that the first clutch is stopped. 6 is released and the second clutch 7 is engaged, and the automatic transmission 3 is set in the power transmission state. In this state, the vehicle is driven only by the motor / generator 5.

  Further, for example, the HEV mode is required during high speed traveling or heavy load traveling. In this HEV mode, the first clutch 6 and the second clutch 7 are both engaged, and the automatic transmission 3 is in a power transmission state. In this state, both the output rotation from the engine 1 and the output rotation from the motor / generator 5 are input to the transmission input shaft 3a, and hybrid traveling by both is performed.

  The motor / generator 5 can recover and recover braking energy when the vehicle decelerates, and can recover surplus energy of the engine 1 as electric power in the HEV mode.

  Here, when transitioning from the EV mode to the HEV mode, the first clutch 6 is engaged, and the engine is started using the torque of the motor / generator 5. At this time, the mode can be smoothly switched by variably controlling the transmission torque capacity of the first clutch 6 and performing the slip engagement. The control at the time of starting the engine will be described in detail later.

  Further, the second clutch 7 functions as a so-called start clutch, and by variably controlling the transmission torque capacity and starting the slip engagement when starting the vehicle, it absorbs torque fluctuations smoothly even in a power train that does not include a torque converter. The start is possible.

  In FIG. 1, the second clutch 7 located between the motor / generator 5 and the drive wheels 2 is interposed between the motor / generator 5 and the automatic transmission 3, but the embodiment shown in FIG. As described above, the second clutch 7 may be interposed between the automatic transmission 3 and the differential gear device 8.

  In the embodiment shown in FIGS. 1 and 2, a dedicated second clutch 7 is provided at the front or rear of the automatic transmission 3, but instead the second clutch 7 is shown in FIG. As shown, an existing forward shift speed selection friction element or reverse shift speed selection friction element in the automatic transmission 3 may be used. In this case, the second clutch 7 is not necessarily one friction element, and an appropriate friction element corresponding to the gear position can be the second clutch 7.

  FIG. 4 shows a control system in the power train of the hybrid vehicle configured as shown in FIGS.

  The control system includes an integrated controller 20 that integrally controls the operating point of the power train. The operating points of this power train are the target engine torque tTe, the target motor / generator torque tTm (or the target motor / generator rotation speed tNm), the target transmission torque capacity tTc1 of the first clutch 6, and the target of the second clutch 7. The transmission torque capacity tTc2.

  The control system also includes at least an engine rotation sensor 11 that detects the engine rotation speed Ne, a motor / generator rotation sensor 12 that detects the motor / generator rotation speed Nm, and an input rotation that detects the transmission input rotation speed Ni. A sensor 13, an output rotation sensor 14 for detecting a transmission output speed No, an accelerator opening sensor 15 for detecting an accelerator pedal depression amount (accelerator opening APO) indicating a required load state of the engine 1, and a motor / generator And a storage state sensor 16 that detects a storage state SOC of the battery 9 that stores the power for 5, and these detection signals are input to the integrated controller 20 to determine the operating point. Has been. Detection signals from various sensors such as a water temperature sensor 17 that detects the coolant temperature of the engine 1 and an oil temperature sensor 18 that detects the oil temperature of the automatic transmission 3 are also input to the integrated controller 20.

  The engine rotation sensor 11, the motor / generator rotation sensor 12, the input rotation sensor 13, and the output rotation sensor 14 are arranged, for example, as shown in FIGS.

  The integrated controller 20 determines the vehicle driving force requested by the driver from the accelerator opening APO, the battery storage state SOC, and the transmission output speed No (vehicle speed VSP) in the input information. Is selected, a target engine torque tTe, a target motor / generator torque tTm (or target motor / generator rotation speed tNm), a target first clutch transmission torque capacity tTc1, and A target second clutch transmission torque capacity tTc2 is calculated.

  The target engine torque tTe is supplied to the engine controller 21, and the engine controller 21 controls the engine 1 so that the actual engine torque Te becomes the target engine torque tTe. For example, the engine 1 is a gasoline engine, and the engine torque Te is controlled via the throttle valve.

  On the other hand, the target motor / generator torque tTm (or the target motor / generator rotation speed tNm) is supplied to the motor / generator controller 22, and the motor / generator controller 22 receives the torque Tm (or rotation speed Nm) of the motor / generator 5. The motor / generator 5 is controlled via the inverter 10 so that becomes the target motor / generator torque tTm (or the target motor / generator rotational speed tNm).

  Further, the integrated controller 20 applies solenoid currents respectively corresponding to the target first clutch transmission torque capacity tTc1 and the target second clutch transmission torque capacity tTc2 to the engagement control solenoid valves (not shown) of the first clutch 6 and the second clutch 7. ) So that the transmission torque capacity Tc1 of the first clutch 6 matches the target transmission torque capacity tTc1, and the transmission torque capacity Tc2 of the second clutch 7 matches the target second clutch transmission torque capacity tTc2. In addition, the engaged state of the first clutch 6 and the second clutch 7 is individually controlled.

  The integrated controller 20 is also connected to an AT controller 31 that controls the automatic transmission 3. The AT controller 31 determines the optimum gear position from the range position selected by the above-mentioned select lever or the like, the vehicle speed VSP (transmission output speed No), and the accelerator opening APO. Shift control is performed by changing the friction elements. Information indicating various states of the automatic transmission 3 is input to the integrated controller 20. As shown in FIG. 3, when the second clutch 7 is substantially constituted by the friction element of the automatic transmission 3, the second clutch 7 is actually controlled via the AT controller 31.

  The hybrid vehicle of the present embodiment starts the stopped engine 1 when the EV mode is changed to the HEV mode due to the driver's intention to accelerate. In starting the engine, in this embodiment, the engine 1 is started in different start modes depending on whether the driver's intention to accelerate is large or not.

  That is, in the hybrid vehicle of the present embodiment, for example, when the change speed ΔAPO of the accelerator opening APO is equal to or less than a predetermined value set in advance, it is determined that the driver's intention to accelerate is not large, and the first start mode When the engine 1 is started and the change rate ΔAPO of the accelerator opening APO is larger than a predetermined value set in advance, it is determined that the driver intends to accelerate, and the engine 1 is compared with the first start mode. The engine 1 is started in the second start mode that takes a long time to start. The change rate ΔAPO of the accelerator opening APO is obtained, for example, by the difference between the accelerator opening APO one calculation before and the current accelerator opening APO.

  Here, in the first start mode, when the engine 1 is started, the transmission torque capacity of the second clutch 7 (target second clutch transmission torque capacity tTc2) is set to be, for example, an engine start motor / generator torque or less. During the cranking of 1, the second clutch 7 is slip-engaged. And while the fluctuation | variation at the time of the engine start by the progress of fastening of the 1st clutch 6 is prevented from being transmitted to the driving wheel 2, it prevents that the output torque to the driving wheel 2 becomes zero during the cranking of the engine 1. To do.

  On the other hand, in the second start mode, when the engine 1 is started, the transmission torque capacity of the first clutch 6 (target first clutch transmission torque capacity tTc1) is transmitted to the first clutch 6 when the engine is started in the first start mode. By making it larger than the torque capacity (target first clutch transmission torque capacity tTc1), the time until the rotation of the engine crankshaft 1a and the rotation of the shaft 4 are synchronized is shortened compared to the first start mode, and the first The transmission torque capacity of the second clutch 7 (target second clutch transmission torque capacity tTc2) is made smaller than the transmission torque capacity of the second clutch 7 (target second clutch transmission torque capacity tTc2) when the engine is started in the first start mode. Thus, the transmission torque capacity of the first clutch 6 (target first clutch transmission torque capacity tTc1) is Mitigating torque fluctuation at the time of synchronizing the rotation of the rotation and the shaft 4 of the engine crankshaft 1a due to the hear.

  The first start mode and the second start mode will be described in detail with reference to FIGS. 5 and 6. FIG. 5 shows an example of the operation of each part when the engine 1 stopped in the first start mode is started, and FIG. 6 shows the operation of each part when the engine 1 stopped in the second start mode is started. An example is shown. 5 and 6 show a situation in which the start timing of the engine 1 and the shift timing of the automatic transmission 3 overlap. This is a situation in which, for example, the accelerator pedal is depressed in the EV travel mode, and the shift stage of the automatic transmission 3 needs to be downshifted. 5 and 6, the driving conditions other than the driver's intention to accelerate are the same.

  For example, when the accelerator pedal is depressed from a coast state where the accelerator pedal is not depressed and the engine is started in the first start mode, first the target transmission torque capacity of the second clutch 7 (target second clutch transmission torque capacity tTc2) is set. The command hydraulic pressure CL2_PRS for the corresponding second clutch 7 is decreased (time t1). The command hydraulic pressure CL2_PRS for the second clutch 7 is a command hydraulic pressure for realizing the target second clutch transmission torque capacity tTc2 of the second clutch 7, and the magnitude of the command hydraulic pressure CL2_PRS is the target second clutch transmission torque capacity tTc2. Therefore, CL2_PRS in FIGS. 5 and 6 will be described as the target second clutch transmission torque capacity tTc2 for convenience of explanation.

  At time t2, in order to downshift the shift stage of the automatic transmission 3, the change of the friction element accompanying the downshift of the shift stage is started. That is, when changing the friction element, the target transmission torque capacity (Release_PRS) of the release side friction element is decreased and the target transmission torque capacity (Apply_PRS) of the engagement side friction element is increased from time t2.

  When the slip of the second clutch 7 is detected, the target first clutch transmission torque capacity tTc1 (CL1_TRQ) is increased toward a predetermined cranking target value to start cranking of the engine 1, and the motor / generator The number of revolutions of the motor / generator 5 is increased so that a maximum motor torque of 5 is obtained (time t3).

  That is, the target first clutch transmission torque capacity tTc2 is decreased and the target first clutch transmission torque capacity tTc1 of the first clutch 6 is increased at the timing of time t3 when the second clutch 7 is slipping. Thus, the torque fluctuation at the time of starting the engine is suppressed from being transmitted to the drive wheel 2 side.

  During cranking of the engine 1 (from time t3 to time t4), the target second clutch transmission torque capacity tTc2 is set to be smaller than the target transmission torque capacity (Release_PRS) of the disengagement side friction element. The driving force transmitted to the driving wheel 2 side by the two clutch 7 is managed.

  Further, during the cranking of the engine 1, the progress of the shift control of the automatic transmission 3 is stopped. That is, the transmission torque capacity (Release_PRS) of the release side friction element and the transmission torque capacity (Apply_PRS) of the engagement side friction element are held so as not to change.

  During cranking of the engine 1, the sum of the target first clutch transmission torque capacity tTc1 and the target second clutch transmission torque capacity tTc2 is set to be equal to or less than the maximum motor torque obtained by the motor / generator 5. .

  Here, until the time t3, the motor / generator 5 is torque-controlled, and is switched to the rotational speed control in the section from the time t3 to the time t5 (described later). Specifically, the rotational speed control is to control the rotational speed Nm (Motor_REV) of the motor / generator 5 to be the target motor / generator rotational speed tNm (Target_REV) indicated by a broken line in FIG. The torque control is to control the torque Tm of the motor / generator 5 to be the target motor / generator torque tTm.

  When the rotation speed (ENGREV) of the engine 1 and the rotation speed (Motor_REV) of the motor / generator 5 are synchronized (time t4), the target first clutch transmission torque capacity tTc1 of the first clutch 6 is set to a predetermined target value after engine start. And the target second clutch transmission torque capacity tTc2 of the second clutch 7 is increased. Further, the shift control of the automatic transmission 3 is resumed, the transmission torque capacity (Release_PRS) of the release side friction element is reduced, and the transmission torque capacity (Apply_PRS) of the engagement side friction element is increased. In the period from time t4 to time t5, the transmission torque capacity of the engagement-side friction element is set to be larger than the target second clutch transmission torque capacity tTc2 of the second clutch 7.

  When it is determined that the slip of the second clutch 7 has converged (time t5), the control of the motor / generator 5 is switched from the rotational speed control to the torque control. In the shift of the automatic transmission 3, after time t5, the transmission torque capacity (Release_PRS) of the release side friction element is completely released, and the transmission torque capacity (Apply_PRS) of the engagement side friction element is completely engaged.

  On the other hand, in the second start mode in which the driver intends to accelerate, when the accelerator pedal is depressed from a coast state in which the accelerator pedal is not depressed, at the time t1 when it is determined to start the engine in the second start mode, Command 2 clutch 7 to be fully released immediately. That is, in the second start mode, at the time t1, the command hydraulic pressure CL2_PRS for the second clutch 7 corresponding to the target transmission torque capacity of the second clutch 7 (target second clutch transmission torque capacity tTc2) decreases toward zero. Let

  Then, in order to quickly downshift the shift stage of the automatic transmission 3, when starting the change of the friction element accompanying the downshift of the shift stage (time t2), the target transmission torque with respect to the disengagement side friction element Command to release the capacity (Release_PRS) at once. Note that the target transmission torque capacity (Apply_PRS) of the engagement-side friction element is increased as in the first start mode.

  When the slip of the second clutch 7 is detected, the target first clutch transmission torque capacity tTc1 (CL1_TRQ) of the first clutch 6 is increased toward a predetermined target value after engine start. That is, at the timing of time t3, the first clutch 6 is instructed to be immediately fully engaged. The motor / generator 5 increases its rotational speed from the timing of time t3 so that the maximum motor torque can be obtained.

  In this way, by instructing the second clutch 7 to be completely released at a time at the timing of time t1, the time until the second clutch 7 starts to slip can be shortened compared to the first start mode. it can. That is, the period (time) from time t1 to time t3 in the second start mode is shorter than the period (time) from time t1 to time t3 in the first start mode.

  Then, at the timing of time t3, the target first clutch transmission torque capacity tTc1 (CL1_TRQ) of the first clutch 6 is increased toward a predetermined target value after starting the engine, so that the engine speed (ENGREV) and the motor / The time until the rotation speed (Motor_REV) of the generator 5 is synchronized can be shortened compared to the first start mode. That is, the period (time) from time t3 to time t4 in the second start mode is shorter than the period (time) from time t3 to time t4 in the first start mode.

  Further, when the target first clutch transmission torque capacity tTc1 (CL1_TRQ) of the first clutch 6 is increased toward a predetermined target value after engine start, the target second clutch transmission torque capacity tTc2 of the second clutch 7 is zero. Therefore, the torque fluctuation accompanying the engagement of the first clutch 6 can be reduced.

  Further, in the second start mode, the target first clutch transmission torque capacity tTc1 during cranking is increased compared to the first start mode, but the release side friction element of the automatic transmission 3 during cranking is increased. Since the target transmission torque capacity (Release_PRS) is reduced, when the start timing of the engine 1 and the shift timing of the automatic transmission 3 overlap, the torque associated with the engagement of the first clutch 6 while shortening the start time of the engine 1 This is suitable for mitigating fluctuations from being transmitted to the drive wheel 2 side.

  Even in the second start mode, the motor / generator 5 is torque-controlled until time t3, and is switched to the rotational speed control in the section from time t3 to time t5 (described later).

  Then, when the rotational speed of engine 1 (ENGREV) and the rotational speed of motor / generator 5 are synchronized (time t4), target second clutch transmission torque capacity tTc2 of second clutch 7 is increased. Further, the shift control of the automatic transmission 3 is resumed, and the transmission torque capacity (Apply_PRS) of the engagement side friction element is increased.

  Even in the second start mode, the shift control of the automatic transmission 3 is not advanced during the cranking of the engine 1, and the transmission torque capacity (Release_PRS) of the release side friction element and the engagement side friction are The transmission torque capacity (Apply_PRS) of the element is held so as not to change.

  When it is determined that the slip of the second clutch 7 has converged (time t5), the control of the motor / generator 5 is switched from the rotational speed control to the torque control. As for the shift of the automatic transmission 3, the transmission torque capacity (Apply_PRS) of the engagement side friction element is completely engaged after time t5.

  FIG. 7 is a flowchart showing an outline of a control flow when the engine is started.

  In S1, it is determined whether or not there is a request for starting the engine 1, and if there is a request for starting the engine 1, the process proceeds to S2.

  In S2, it is determined whether or not the driver's intention to accelerate is large. If the driver's intention to accelerate is large, the process proceeds to S4. Otherwise, the process proceeds to S3.

  In S3, the engine start mode is determined to be the first start mode, and the engine 1 is started in the first start mode.

  In S4, the engine start mode is determined to be the second start mode, and the process proceeds to S5. In S5, compared to the first start mode, the transmission torque capacity of the first clutch 6 at the time of starting the engine is set larger, the transmission torque capacity of the second clutch 7 is set smaller, and the engine 1 is operated in the second start mode. Start.

  The present invention is not limited to the above-described embodiment. For example, in the above-described embodiment, the transmission torque capacity of the first clutch 6 and the second clutch 7 during the cranking of the engine 1 are further increased. The transmission torque capacity may be continuously changed according to the driver's intention to accelerate. In this case, the transmission torque capacities of the first clutch 6 and the second clutch 7 are continuously varied depending on the driving conditions, so that the first clutch 6 can be engaged due to the difference in the driver's intention of acceleration. The accompanying torque fluctuation can be averaged.

  In the above-described embodiments, two start modes are set according to the driver's intention to accelerate. However, three or more start modes may be set according to the driver's intention to accelerate. .

  The driver's intention to accelerate may be determined using only the change rate ΔAPO of the accelerator opening APO, but may be determined using both the change rate ΔAPO of the accelerator opening APO and the accelerator opening APO. Is possible. In this case, for example, the acceleration intention of the driver is large when the change rate ΔAPO of the accelerator opening APO is larger than a predetermined value and the accelerator opening APO is larger than a predetermined value. Otherwise, it is determined that the intention to accelerate is small.

DESCRIPTION OF SYMBOLS 1 ... Engine 3 ... Automatic transmission 5 ... Motor / generator 6 ... 1st clutch 7 ... 2nd clutch 9 ... Battery 10 ... Inverter 20 ... Integrated controller 21 ... Engine controller 22 ... Motor / generator controller

Claims (4)

An engine and a motor are provided as drive sources, and the engine and the motor are connected via a clutch capable of changing a transmission torque capacity, and when the engine is started, the clutch is engaged to drive the motor. In the engine start control device for a hybrid vehicle that performs cranking of the engine by
When starting the engine that is stopped due to the result of the driver's accelerator operation, when the driver's intention to accelerate is large, the engine during cranking of the engine is larger than when the driver's acceleration intention is small. An engine start control device for a hybrid vehicle, wherein a transmission torque capacity of a clutch is increased. A second clutch capable of changing a transmission torque capacity between the motor and a drive wheel of the vehicle;
When the driver's intention to accelerate is large, the transmission torque capacity of the second clutch during cranking of the engine is made smaller than when the driver's intention to accelerate is small. Engine start control device. An automatic transmission that achieves a plurality of shift speeds by switching friction elements between the motor and the drive wheel;
In a situation where the timing of starting the engine that is stopped due to the result of the accelerator operation of the driver overlaps with the timing of shifting of the automatic transmission,
3. The transmission torque capacity of the disengagement friction element of the automatic transmission at the time of shifting is lowered when the driver's intention to accelerate is larger than when the driver's intention to accelerate is small. 2. An engine start control device for a hybrid vehicle according to 1.   When starting the engine that is stopped due to the result of the driver's accelerator operation, the transmission torque capacity of the clutch and the transmission torque capacity of the second clutch during cranking of the engine are determined according to the acceleration intention of the driver. The engine start control device for a hybrid vehicle according to claim 2 or 3, wherein the engine start control device is continuously changed according to the degree.

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