WO2018078803A1 - Hybrid vehicle control method and control device - Google Patents

Abstract

The purpose of the present invention is to prevent a reduction in driving power transmitted to a drive wheel when there is a demand for acceleration during cranking start of an engine. Provided is an FF hybrid vehicle control method in which cranking start of an engine (1) is initiated using a motor generator (3) as a starter motor when an engine start determination is output while an EV mode is selected. While the EV mode is selected, a predicted motor speed increase amount ΔNm during cranking start is calculated assuming that the vehicle is accelerating. A target motor speed Nmt is calculated by adding the predicted motor speed increase amount ΔNm to a current motor speed Nm. When it is assumed that cranking start is initiated at a current motor operation point A while the EV mode is selected, a predicted arrival driving point B is set to a position at which the motor speed Nm reaches the target motor speed Nmt after being increased without causing motor output to be reduced during cranking start, and using the predicted arrival driving point B as a determination reference position, engine start determination is performed.

Description

Control method and control apparatus for hybrid vehicle

The present disclosure relates to a control method and a control apparatus for a hybrid vehicle that starts cranking of an engine using a motor as a start motor when a start determination is made when an electric vehicle mode is selected.

Conventionally, the EV → HEV switching line is set by subtracting the cranking torque required for engine cranking start from the maximum torque curve characteristic of the motor. When “EV mode” is selected, if the motor operating point due to the motor speed and motor torque crosses the EV → HEV switching line, an engine start request is issued, and the engine is cranked using the motor as the start motor. Is known (see, for example, Patent Document 1).

JP 2013-107539 A

However, in the conventional system, it is assumed that the motor speed does not change during the cranking start from the start to the completion of the engine start according to the engine start request, and the EV → HEV switching is performed by subtracting the cranking torque from the maximum motor torque. A line is set. Therefore, there is an acceleration request by depressing the accelerator during cranking start, and when the motor speed increases, the torque transmitted from the motor to the drive wheel side is EV → HEV so as to secure the cranking torque to the engine side. It decreases along the switching line (motor driving force limit line during startup). At this time, the EV → HEV switching line with the cranking torque as a margin with respect to the maximum torque curve characteristic of the motor is set lower than the equal output line of the motor output. For this reason, when there is an acceleration request during cranking start, there is a problem that the driving force transmitted to the driving wheels is reduced as the motor output decreases.

The present disclosure has been made paying attention to the above-described problem, and an object thereof is to prevent a reduction in driving force transmitted to driving wheels when there is an acceleration request during engine cranking start.

In order to achieve the above object, the present disclosure has an electric vehicle mode and a hybrid vehicle mode as operation modes, and when an engine start determination is issued during selection of the electric vehicle mode, the motor is used as a start motor. Start cranking start.
In this hybrid vehicle control method, when the electric vehicle mode is selected, it is assumed that the vehicle accelerates during cranking start from the start of engine start to the completion of start, and the predicted motor rotation during cranking start accompanying the assumed vehicle acceleration Find the amount of increase.
The target motor rotational speed is obtained by adding the predicted motor rotational speed increase to the current motor rotational speed.
When the cranking start is assumed to start at the current motor operating point while the electric vehicle mode is selected, the target motor speed is reached by increasing the motor speed without decreasing the motor output during cranking start. The engine start determination is performed using the determined position as the predicted reaching operation point and the predicted reaching operation point as the determination reference position.

In this way, the engine start determination is performed based on the assumption that the vehicle accelerates during cranking start, so that when there is an acceleration request during engine cranking start, the driving force transmitted to the drive wheels is reduced. Can be prevented.

1 is an overall system diagram illustrating a drive system and a control system of an FF hybrid vehicle to which a control method and a control device of Example 1 are applied. FIG. 3 is a block configuration diagram illustrating a start determination unit and a target limit torque generation unit included in the engine start control unit of the integrated controller according to the first embodiment. 4 is a flowchart showing a flow of an engine start control process executed by the integrated controller of the first embodiment. It is a map figure which shows the prediction motor rotation increase amount (DELTA) Nm map which searches the motor rotation increase amount map value by vehicle speed and battery output. FIG. 6 is a start determination explanatory diagram showing an outline of a start determination operation during the selection of “EV mode” in the first embodiment by a relational characteristic between the motor speed of the motor generator and the motor torque. Time chart showing characteristics of motor rotational speed, transmission input rotational speed, engine rotational speed, motor maximum torque, target driving force, realizable driving force, and actual motor torque for explaining the engine start control operation of the first embodiment It is. FIG. 10 is a problem explanatory diagram illustrating a problem of engine start control during selection of an “EV mode” in a comparative example, by a relational characteristic between a motor speed of a motor generator and a motor torque. FIG. 7 is an operation explanatory diagram showing an outline of an engine start control operation during selection of an “EV mode” in the first embodiment, using a relational characteristic between the motor speed of the motor generator and the motor torque.

Hereinafter, the best mode for realizing the hybrid vehicle control method and control device of the present disclosure will be described based on Example 1 shown in the drawings.

First, the configuration will be described.
The control method and the control device in the first embodiment are applied to an FF hybrid vehicle having a parallel hybrid drive system called a one-motor / two-clutch and equipped with a belt type continuously variable transmission as a transmission. Hereinafter, the configuration of the first embodiment will be described by being divided into an “overall system configuration”, an “engine start control block configuration”, and an “engine start control processing configuration”.

[Overall system configuration]
FIG. 1 shows a drive system and a control system of an FF hybrid vehicle (an example of a hybrid vehicle) to which the control method and the control device of the first embodiment are applied. Hereinafter, based on FIG. 1, the whole system configuration by the drive system and control system of FF hybrid vehicle is demonstrated.

As shown in FIG. 1, the drive system of the FF hybrid vehicle includes an engine 1, a first clutch 2, a motor generator 3, a second clutch 4, a transmission input shaft 5, and a belt type continuously variable transmission 6. And a transmission output shaft 7, a final gear 8, and left and right drive wheels 9, 9. The operation mode of the parallel hybrid drive system includes an electric vehicle mode (hereinafter referred to as “EV mode”), a hybrid vehicle mode (hereinafter referred to as “HEV mode”), and a drive torque control start mode (hereinafter referred to as “WSC”). Mode ")) and the like.

“EV mode” is a mode in which the first clutch 2 is disengaged and the vehicle is driven only by the power of the motor generator 3. The “HEV mode” is a mode in which the first clutch 2 is engaged and the vehicle travels in any of the motor assist mode, the traveling power generation mode, and the engine mode. The “WSC mode” maintains the slip engagement state of the second clutch 4 by controlling the number of revolutions of the motor generator 3 at the time of P, N → D selection start from the “EV mode” or “HEV mode”. Then, the driving force transmitted to the left and right drive wheels 9, 9 via the belt-type continuously variable transmission 6 or the like as the engagement torque capacity of the second clutch 4 is determined by the accelerator opening APO and the vehicle speed VSP. It is a mode to start while controlling to be equivalent to the driving force. “WSC” is an abbreviation of “Wet Start clutch”.

The engine 1 is capable of lean combustion, and is controlled so that the engine torque matches the command value by controlling the intake air amount by the throttle actuator, the fuel injection amount by the injector, and the ignition timing by the spark plug. As a start mode of the engine 1, “MG start”, in which the motor generator 3 is used as a start motor, the second clutch 4 is in a slip engagement state, and the engine 1 is cranked while increasing the engagement torque of the first clutch 2, is basic. And Note that “starter start” in which the engine 1 is started by the starter motor 10 is also an option, but “starter start” is only performed when a specific condition is satisfied, for example, when a start request is made at an extremely low temperature. Selected as the target state.

The first clutch 2 is interposed at a position between the engine 1 and the motor generator 3, and is set to “EV mode” when released and set to “HEV mode” when engaged. As the first clutch 2, for example, a normally open dry multi-plate clutch or the like is used, and fastening / slip fastening / release is performed by hydraulic control.

The motor generator 3 has an AC synchronous motor structure, and performs torque control and rotation speed control by demonstrating a motor function when starting or running. During braking or deceleration, the generator function is performed to convert vehicle kinetic energy from the left and right drive wheels 9 and 9 into electric energy, and regenerative control is performed to charge the battery 12 via the inverter 11.

The second clutch 4 is a normally open wet multi-plate clutch or wet multi-plate brake provided in the forward / reverse switching mechanism, and generates a clutch transmission torque with the CL2 engagement torque by hydraulic control as an upper limit torque. The second clutch 4 sends torque output from the drive source to the left and right drive wheels 9 and 9 via the transmission input shaft 5, the belt type continuously variable transmission 6, the transmission output shaft 7, and the final gear 8. Communicate. As shown in FIG. 1, the second clutch 2 is set at a position between the motor generator 3 and the belt-type continuously variable transmission 6, and the belt-type continuously variable transmission 6 and the left and right drive wheels 9, 9 are set. You may set to the position between.

The belt type continuously variable transmission 6 is bridged between a primary pulley 61 connected to the transmission input shaft 5, a secondary pulley 62 connected to the transmission output shaft 7, and the primary pulley 61 and the secondary pulley 62. And a pulley belt 63. A stepless transmission ratio is obtained according to the winding diameter of the pulley belt 63 around the primary pulley 61 and the secondary pulley 62. That is, when the belt clamping width of the primary pulley 61 is widened and the belt clamping width of the secondary pulley 62 is narrowed, the gear ratio changes to the low gear ratio side. Further, as the belt clamping width of the primary pulley 61 becomes narrower and the belt clamping width of the secondary pulley 62 becomes wider, the gear ratio changes to the High gear ratio side.

As shown in FIG. 1, the control system of the FF hybrid vehicle includes an integrated controller 14, a transmission controller 15, a clutch controller 16, an engine controller 17, a motor controller 18, and a battery controller 19. . The engine speed sensor 21, the motor speed sensor 22, the transmission input speed sensor 23, the CVT oil temperature sensor 24, the accelerator opening sensor 25, the G sensor 26, the brake sensor 27, and the wheels A speed sensor 28 and an inhibitor switch 29 are provided.

The integrated controller 14 is a controller that manages the parallel hybrid drive system in an integrated manner, and calculates a target driving force, a target state, and the like from the battery SOC state, accelerator opening APO, vehicle speed VSP, hydraulic oil temperature, and the like. Then, based on the calculation result, command values for the actuators (engine 1, first clutch 2, motor generator 3, second clutch 4, belt type continuously variable transmission 6) are calculated, via CAN communication line 20. To each of the controllers 15, 16, 17, 18, and 19.

The transmission controller 15 performs shift control by controlling the pulley hydraulic pressure supplied to the primary pulley 61 and the secondary pulley 62 of the belt-type continuously variable transmission 6 so as to achieve the shift command from the integrated controller 14.

The clutch controller 16 inputs sensor information from the engine speed sensor 21, the motor speed sensor 22, the transmission input speed sensor 23, and the like, and also inputs a command from the integrated controller 14. Then, a CL1 hydraulic pressure command value to the first clutch 2 is output according to the selected operation mode and the like. Further, a CL2 hydraulic pressure command value to the second clutch 4 is output in response to a CL2 slip request or the like.

The engine controller 17 inputs sensor information from the engine speed sensor 21 and performs torque control and speed control of the engine 1 so as to achieve the engine torque command value and the engine speed command value from the integrated controller 14. Do. The engine controller 17 outputs a fuel injection command and an ignition command when the cranking rotational speed reaches a predetermined rotational speed when the engine is started.

The motor controller 18 outputs a control command to the inverter 8 so as to achieve the motor torque command value and the motor rotation speed command value from the integrated controller 14, and performs torque control and rotation speed control of the motor generator 3. The inverter 11 performs DC / AC mutual conversion, and converts the discharge current from the battery 12 into the drive current of the motor generator 3 during power running. Further, during regeneration, the generated current from the motor generator 3 is converted into a charging current for the battery 12.

The battery controller 19 manages the charge capacity (battery SOC) of the battery 9 and the battery temperature, and transmits battery information to the integrated controller 14 and the engine controller 17. The battery output Pout is calculated based on the battery SOC and the battery temperature.

[Engine start control block configuration]
FIG. 2 shows a start determination unit 141 and a target limit torque generation unit 142 included in the engine start control unit 140 of the integrated controller 14 of the first embodiment. Hereinafter, detailed configurations of the start determination unit 141 and the target limit torque generation unit 142 will be described.

The start determination unit 141 includes a predicted motor rotation increase amount calculation unit 141a, a driving force calculation unit 141b, a start determination unit 141c, and a target state calculation unit 141d.

The predicted motor rotation increase calculation unit 141a receives the vehicle speed VSP and the battery output Pout, searches for a motor rotation increase map value ΔNmMAP using a preset motor rotation increase map, and calculates the map value ΔNmMAP using a correction coefficient. The predicted motor rotation increase amount ΔNm is calculated after correction. That is, it is assumed that the vehicle is accelerated by the accelerator depressing operation by the driver during the cranking start from the start of the engine 1 to the completion of the start while the “EV mode” is selected, and the cranking start during the assumed vehicle acceleration is being performed. A predicted motor rotation increase amount ΔNm is calculated.

The driving force calculation unit 141b inputs the predicted motor rotation increase amount ΔNm and the like, assumes that cranking start is started at the current motor operation point, and adds the predicted motor rotation increase amount ΔNm to the current motor rotation number Nm. The target motor speed Nmt is calculated. Then, the motor driving torque that can be realized at the predicted reaching operation point at which the motor operation point has reached the target motor rotation speed Nmt is subtracted from the maximum motor torque by the battery output Pout from the cranking torque necessary for cranking start of the engine 1. Calculate by Further, the motor torque to the drive wheels 9 and 9 that can be realized at the predicted reaching operation point that has reached the target motor rotation speed Nmt is considered in consideration of the gear ratio of the belt-type continuously variable transmission 6, the gear ratio of the final gear 8, and the like. The driving force (1 sec rating) that can be realized is calculated by converting the driving force to the driving wheels 9 and 9.

The start determination unit 141c performs engine start determination for starting cranking start of the engine 1 by comparing the drive force that can be realized from the drive force calculation unit 141b with the target drive force. That is, the “EV mode” is maintained while it is determined that the realizable driving force> the target driving force. However, if it is determined that the realizable driving force ≦ the target driving force, an engine start determination flag is output. The target driving force is determined by the accelerator opening APO and the vehicle speed VSP at the present time using a preset target driving force map.

The target state calculation unit 141d receives the output from the start determination unit 141c, the starter start request, and the MG start request, and calculates the target state (“MG start”, “starter start”). That is, when an engine start determination flag is output from the start determination unit 141c with insufficient driving force and an MG start request is input, “MG start” is calculated as the target state.

The target limit torque generator 142 includes an upper limit motor torque calculator 142a, a driving force calculator 142b, an upper limit limiter 142c, and a change rate limit 142d.

The upper limit motor torque calculation unit 142a receives the predicted motor rotation increase ΔNm during cranking start calculated by the predicted motor rotation increase calculation unit 141a, and the predicted reaching operation in which the motor operating point has reached the target motor rotation number Nmt. The upper limit motor torque that can be realized in terms of points is calculated. Then, the upper limit motor torque and the battery output Pout are input and converted into a driving force that can realize the upper limit motor torque.

The driving force calculation unit 142b inputs a driving force equivalent to the upper limit motor torque calculated by the upper limit motor torque calculation unit 142a, limits the rate of change based on the cranking torque, etc., and is realized during cranking start. The driving force that can be calculated is calculated. That is, the rate of increase in motor torque during cranking start is limited so as to ensure cranking torque when the motor operating point reaches the target motor rotation speed Nmt.

The upper limit limiting unit 142c inputs the driving force that can be realized during cranking start from the driving force calculation unit 142b and the target transmission input torque, and limits the upper limit of the driving force that can be realized.

The change rate limit 142 d is a drive force that can be transmitted to the drive wheels 9 and 9 by limiting the change rate of the drive force that can be realized with the upper limit limited by the upper limit limiting unit 142 c. The target force output from the motor generator 3 is converted by converting the driving force that can be transmitted to the drive wheels 9 and 9 in consideration of the gear ratio of the belt-type continuously variable transmission 6, the gear ratio of the final gear 8, and the like. Torque (= target CL2IN torque) is generated.

The generated target limit torque is realized by outputting an engagement torque command corresponding to the target limit torque to the second clutch 4 during cranking start in which the second clutch 4 is in the slip engagement state. That is, of the torque that can be output from the motor generator 3 by the rotational speed control, the upper limit torque is managed by the engagement torque of the second clutch 4 for the shared torque output to the left and right drive wheels 9 and 9 side.

[Engine start control processing configuration]
FIG. 3 shows an engine start control process flow executed by the integrated controller 14 of the first embodiment. Hereinafter, each step of FIG. 3 representing the engine start control processing configuration will be described.

In step S1, it is determined whether or not “EV mode” is being selected. If YES (while selecting “EV mode”), the process proceeds to step S3. If NO (other than selecting “EV mode”), the process proceeds to step S2.

In step S2, following the determination that “EV mode” is not being selected in step S1, other control is executed, and the process proceeds to the end.
Here, “other control” refers to HEV mode control performed during selection of “HEV mode”, mode transition control from “HEV mode” to “EV mode”, and the like.

In step S3, following the determination that “EV mode” is being selected in step S1, the motor rotation increase map value ΔNmMAP is retrieved, and the motor rotation increase map value ΔNmMAP is multiplied by the correction coefficient to predict the motor rotation. The increase amount ΔNm is corrected and calculated, and the process proceeds to step S4.
Here, when calculating the “predicted motor rotation increase amount ΔNm”, it is assumed that the accelerator pedal is depressed during cranking start, and further, the gear ratio of the belt type continuously variable transmission 6 is Suppose that it is the lowest gear ratio.

The search for the motor rotation increase map value ΔNmMAP is performed using the battery output Pout, the vehicle speed VSP, and the motor rotation increase map (FIG. 4). That is, the amount of motor rotation increase due to acceleration for each battery output Pout and each vehicle speed VSP is estimated, and the motor rotation increase amount during cranking start is defined as the motor rotation increase amount map shown in FIG. In this motor rotation increase amount map, the motor rotation increase amount map value ΔNmMAP is increased as the battery output Pout increases and the vehicle speed VSP decreases. The reason for obtaining the predicted motor rotation increase amount ΔNm for each battery output Pout is that the smaller the battery output Pout, the smaller the motor maximum torque that can be output at that rotation speed, so the vehicle acceleration decreases (= the motor rotation increase amount decreases). Because it will be less).

The reason why the predicted motor rotation increase ΔNm is calculated by (correction coefficient × motor rotation increase map value ΔNmMAP) is not simply to reduce the selection area of “EV mode” in response to the acceleration request during cranking start. This is so that only the problem scene is effective. Therefore, for the following (a) and (b), the motor rotation increase map value ΔNmMAP is corrected.
(a) In particular, when the vehicle speed VSP is equal to or higher than a predetermined vehicle speed (for example, 15 km / h), the gear ratio becomes high, and thus the passenger sensitivity of the G pulling shock is small. Therefore, a correction coefficient corresponding to the vehicle speed VSP is applied so as to reduce the influence of the motor rotation increase map value ΔNmMAP determined by the motor rotation increase map. For example, the drivability evaluation is performed, and the motor rotation increase map value ΔNmMAP may be ignored for a high vehicle speed region without the influence of the G pulling shock. In this case, the predicted motor rotation increase ΔNm is set to zero. .
(b) The road gradient is estimated based on the longitudinal G information and the like, and the motor rotation increase map value ΔNmMAP due to the road gradient is corrected. For example, when the road surface gradient is climbing, the vehicle acceleration is lower than that on a flat road. Therefore, correction is performed to decrease the motor rotation increase map value ΔNmMAP using a correction coefficient corresponding to the climbing gradient.
The reason for this is that when calculating the “predicted motor rotation rise amount ΔNm” by calculation,
Predicted motor rotation increase [rpm] = acceleration [m / s ^ 2] x gear ratio ÷ tire diameter [m] x start time ... (1)
Acceleration [m / s ^ 2] = {input motor torque [Nm] x gear ratio ÷ tire diameter [m]-(rolling + air resistance) [N]-inertia [N]-gradient resistance [N]} ÷ vehicle weight [kg]… (2)
The following formula is used. The input motor torque is calculated on the assumption that the drive maximum torque (= maximum motor torque−cranking torque) that can be output at the vehicle speed (converted to the motor rotation speed in consideration of the gear ratio) lasts for the start time. That is, as is clear from the above equation (2), the “predicted motor rotation increase amount ΔNm” is influenced by the gradient resistance.

In step S4, following the calculation of the predicted motor rotation increase amount ΔNm in step S3, the current motor rotation speed Nm and the predicted motor rotation increase amount ΔNm are added together, and it is assumed that there is acceleration during cranking start. The target motor rotation speed Nmt predicted to be reached is calculated, and the process proceeds to step S5.

In step S5, following the calculation of the target motor rotation speed Nmt in step S4, the “realizable driving force” is calculated from the target motor rotation speed Nmt, the battery output Pout, and the start margin, and the process proceeds to step S6.
Here, the maximum motor torque at the target motor rotation speed Nmt is obtained from “battery output Pout”. “Starting margin” refers to “cranking torque” necessary for cranking the engine 1 using the motor generator 3. “Achievable driving force” is the target motor speed Nmt by increasing the motor speed Nm while maintaining the motor torque Tm at the current motor operating point out of the current motor operating point (Nm, Tm). It is assumed that the predicted reaching operation point by is reached. This is a value obtained by converting the motor torque obtained by subtracting the cranking torque from the maximum motor torque at the predicted reaching operation point into the driving force transmitted to the drive wheels 9 and 9.

In step S6, following the calculation of “realizable driving force” in step S5, it is determined whether or not the realizable driving force is equal to or less than the target driving force. If YES (realizable driving force ≦ target driving force), the process proceeds to step S7. If NO (realizable driving force> target driving force), the process returns to step S3 to maintain the “EV mode”.
Here, the “target driving force” is determined by the current accelerator opening APO and the vehicle speed VSP using a preset target driving force map (not shown).

In step S7, following the start of engine start based on the determination that the driving force that can be realized in step S6 ≦ the target driving force, a target limit torque is generated using the predicted motor rotation increase amount ΔNm, and the process proceeds to step S8.
Here, the “target limit torque” is the motor operating point (Nm, Tm) during cranking start that increases until the motor speed Nm reaches the predicted operating point by the target motor speed Nmt from the start of starting. This means the motor torque Tm that is subject to an upper limit and a change rate limit. In the first embodiment, the “target limit torque” is set to a value that maintains the motor torque Tm at the start determination.

In step S8, following the generation of the target limiting torque in step S7 or the determination that the CL2 slip engagement state is not established in step S9, CL2 slip control is performed, and the process proceeds to step S9.
Here, the “CL2 slip control” is performed by setting the target engagement torque of the second clutch 4 to be equivalent to the target limit torque, and controlling the rotation speed of the motor generator 3. In the rotation speed control of the motor generator 3, the value obtained by adding the target slip rotation speed to the transmission input rotation speed INPREV to the belt type continuously variable transmission 6 is set as the motor rotation speed target value, and the actual motor rotation speed is set as the motor rotation speed target. Control to match the value.

In step S9, following the CL2 slip control in step S8, it is determined whether or not the second clutch 4 is in the slip engagement state. If YES (CL2 slip engagement state), the process proceeds to step S10, and if NO (not CL2 slip engagement state), the process returns to step S8.
Here, in the “slip engagement state of the second clutch 4”, when the engagement torque of the second clutch 4 becomes the target engagement torque (= target limit torque) and the differential rotation of the second clutch 4 becomes the target slip rotation speed, It is judged that it is in a slip fastening state.

In step S10, following the determination that the CL2 slip engagement state is set in step S9 or the determination that the engine start is not completed in step S11, the engine 1 is cranked and the process proceeds to step S11.
Here, “the cranking start of the engine 1” starts the engagement of the first clutch 2 released in the “EV mode”, and the cranking torque portion of the motor torque from the motor generator 3 is set to the first. This is done by transmitting to the engine 1 via the clutch 2.

In step S11, following the cranking start of the engine 1 in step S10, it is determined whether the engine start is completed. If YES (engine start is complete), the process proceeds to step S12. If NO (engine start is not complete), the process returns to step S10.
Here, the determination of “engine start complete” is made when the first clutch 2 is completely engaged (motor rotation speed≈engine rotation speed) after the first explosion determination of the engine 1 is made.

In step S12, following the determination that the engine start is complete in step S11, the operation mode is changed from "EV mode" to "HEV mode", and the process proceeds to the end.

Next, the operation will be described.
The operation of the first embodiment will be described separately for “engine start control processing operation”, “engine start control operation”, “engine start control contrast operation”, and “engine start control characteristic operation”.

[Engine start control processing action]
The engine start control processing operation will be described below based on the flowchart shown in FIG. 3 and the maximum torque curve characteristic of the motor shown in FIG.

When the “EV mode” is being selected, the process proceeds to step S1, step S2, step S3, step S4, step S5, and step S6 in the flowchart of FIG. Then, the driving force that can be realized in step S6> target driving force, and while the start determination condition is not satisfied, the flow of step S3 → step S4 → step S5 → step S6 is repeated, and the “EV mode” Is maintained.

In step S3, a predicted motor rotation increase amount ΔNm is calculated. In step S4, the current motor rotation speed Nmo and the predicted motor rotation increase amount ΔNm are added, and reached when it is assumed that acceleration is occurring during cranking start. Then, the predicted target motor speed Nmt is calculated. In step S5, the driving force that can be realized by the target motor rotation speed Nmt, the battery output Pout, and the start margin is calculated. In step S6, it is determined whether or not the driving force that can be realized is equal to or less than the target driving force.

Thereafter, when the driving force that can be realized in step S6 ≦ target driving force and the start determination condition is satisfied, the cranking start of the engine 1 is started, and the process proceeds from step S6 to step S7 → step S8 → step S9. While it is determined in step S9 that the CL2 slip engagement state does not come out, the flow from step S8 to step S9 is repeated.

In step S7, the target limit torque is generated using the predicted motor rotation increase amount ΔNm. In step S8, CL2 slip control is performed. In step S9, it is determined whether or not the second clutch 4 is in the slip engagement state. Is done.

If it is determined in step S9 that the second clutch 4 is in the slip engagement state, the process proceeds from step S9 to step S10 to step S11. While it is determined in step S11 that the engine has not been started yet, the flow from step S10 to step S11 is repeated.

In step S10, the motor generator 3 is used as a starter motor, and the engine 1 is cranked and started by engaging the first clutch 2. In step S11, it is determined whether the engine start is completed. If it is determined in step S11 that the engine has been started, the process proceeds from step S11 to step S12 → end, and the operation mode is changed from “EV mode” to “HEV mode”.

In the start determination in step S6, it is assumed that the motor operation point (Nm, Tm) at the current time is the motor operation point A while the “EV mode” is selected, as shown in FIG. Among the motor operating points A, the motor operating point B in which the motor rotational speed Nm increases to the target motor rotational speed Nmt obtained by adding the predicted motor rotational speed increase ΔNm to the current motor rotational speed Nmo while maintaining the motor torque Tm. It is assumed that the vehicle has moved to (predicted reaching operation point). At this motor operating point B, the motor torque obtained by subtracting the margin torque from the maximum motor torque is the motor torque that can be transmitted to the left and right drive wheels 9 and 9 side (realizable motor torque). Therefore, for example, as shown in FIG. 5, when the motor operating point moves from A ′ to A and the motor torque that can be realized at the motor operating point B (predicted reaching operating point) becomes equal to or less than the target driving torque, the engine starts. A decision is issued.

When the cranking start is started at the motor operating point A, the motor torque Tm is maintained at a constant torque by the control of the slip engagement torque of the second clutch 4, and the motor operating point is almost completed when the cranking start is completed. Move to position B. At this motor operating point B, the motor torque obtained by subtracting the motor torque that can be realized from the maximum motor torque becomes the cranking torque, and the start of the engine 1 using the cranking torque is ensured.

Thus, first, assuming that there is acceleration of the vehicle during cranking start, a predicted motor rotation increase amount ΔNm during cranking start accompanying acceleration is calculated. The start determination in the engine start control process is performed using the target motor rotation speed Nmt obtained by adding the predicted motor rotation increase amount ΔNm to the current motor rotation speed Nmo as a determination reference position. Further, for the motor torque during cranking start, the target motor rotation speed Nmt obtained by adding the predicted motor rotation increase amount ΔNm to the current motor rotation speed Nmo is used as a determination reference position, and the motor operation point B (predicted reaching operation point) is set. When it reaches, the target limit torque is generated so as to leave the cranking torque.

[Engine start control action]
FIG. 6 is a time chart illustrating an example of an engine start control action by the engine start control process of the first embodiment. Hereinafter, the engine start control operation will be described with reference to FIG.

When the accelerator is depressed at time t1, the motor torque starts to increase. Then, the target motor rotation speed Nmt obtained by adding the predicted motor rotation speed increase ΔNm to the current motor rotation speed Nmo is used as the determination reference position, and the realizable driving force and the target driving force are determined. The “EV mode” is maintained until the time t2 is reached from the time t1 as the power. Then, when the time t2 is reached and the realizable driving force = target driving force is reached, the engine start is started, and the time period from the time t2 to the time t7 when the engine start is completed becomes the cranking start interval.

When the engine start is started at time t2, as shown in the motor torque characteristic surrounded by the arrow C in FIG. 6, based on the generation of the target limit torque until the time t6 when the first explosion of the engine 1 is determined. The motor torque at the time when the engine 1 is determined to start is maintained. Then, CL2 slip engagement control is started from time t2, and when it is determined that the slip engagement state is at time t3, after time t2, the difference rotation speed between the motor rotation speed and the transmission input rotation speed INPREV is The target slip rotational speed is maintained. Then, the driving force and the maximum motor torque (motor upper limit) that can be realized immediately after time t3 start to decrease.

When the generation of the engagement torque of the first clutch 2 is started at time t5, the cranking for increasing the engine speed is started by the motor generator 3, and the initial explosion determination is made at time t6. When the first explosion is determined at time t6, the engine torque is added to the motor torque as the driving force that can be realized, and the driving force that can be realized until time t7 increases. When the first clutch 2 is completely engaged at time t7 and the motor rotational speed and the engine rotational speed become the same rotational speed, the engine start is completed and the mode transitions to the “HEV mode”. In the “HEV mode”, the driving force that can be realized by the sum of the engine 1 and the motor generator 3 is increased, and the driving force that can be realized reaches the target driving force at time t8.

On the other hand, in the case of the comparative example in which the engine start is determined using the EV → HEV switching line, the engine start is started at the time t4 when the driving force at which the motor torque can be realized is reached, as shown by the broken line characteristics in FIG. Is done. After time t4, the motor torque decreases along with the characteristics of the driving force that can be realized so as to ensure the cranking torque.

[Contrast effect of engine start control]
First, a problem in a comparative example in which engine start is determined using an EV → HEV switching line and engine start control is performed will be described with reference to FIG.

In the case of the comparative example, as shown in FIG. 7, the EV → HEV switching line is set by subtracting the cranking torque necessary for engine cranking start from the maximum torque curve characteristic of the motor. When “EV mode” is selected, the motor operating point D ′ based on the motor speed Nm and motor torque Tm moves to the motor operating point D. When the EV → HEV switching line is crossed, an engine start determination is issued and the motor is started. Start cranking the engine as a motor.

That is, the EV → HEV switching line is set on the assumption that the motor speed does not change by maintaining the vehicle running at a constant speed during the cranking start from the start to the completion of the engine start by the start determination. During cranking start, the torque obtained by subtracting the cranking torque from the motor torque to the engine side is used as the driving force that can be transmitted to the driving wheel side. Therefore, there is an acceleration request by depressing the accelerator during cranking start, and when the motor speed increases, the motor drive torque transmitted to the drive wheel side is EV → HEV so as to secure the cranking torque to the engine side. Along the switching line (driving force limit line during start-up), it decreases to the motor operating point D ″. At this time, the EV → HEV switching line with a margin of cranking torque for the maximum torque curve characteristic of the motor Therefore, when there is an acceleration request during cranking start, there is a decrease in motor torque indicated by arrow E in FIG. The driving force transmitted to the wheel is reduced.

On the other hand, in the case of the first embodiment, it is assumed that the motor operation point reaches the motor operation point F due to the movement from the motor operation point F ′ as shown in FIG. 8 while the “EV mode” is selected. When reaching this motor operating point F, it is assumed that cranking start is started, and the target motor rotational speed Nmt is calculated by adding the predicted motor rotational speed increase ΔNm to the current motor rotational speed Nmo. Then, at the motor operating point F ″ (predicted reaching operating point) that reaches the target motor rotational speed Nmt, if the motor torque can be maintained during cranking start and a torque margin equivalent to the cranking torque remains, the engine start determination I try to put out.

Therefore, when the engine start determination is made at the motor operating point F and the cranking start of the engine 1 is started, there is an acceleration request by the accelerator depressing operation during the cranking start, and even if the motor speed increases, the drive wheel side The motor torque transmitted to the motor is maintained at the motor operating point F as shown from the motor operating point F to the motor operating point F ″ in FIG. 8. At this time, cranking start of the engine 1 is started. The equal output line of the motor output at the motor operating point F is set at a torque position lower than the motor operating point F ″. For this reason, when there is an acceleration request during cranking start, there is an increase in motor output during cranking start, as indicated by arrow G in FIG. 8, and as a result, the drive transmitted to the left and right drive wheels 9, 9. Power rises.

[Characteristics of engine start control]
In the first embodiment, while the “EV mode” is selected, it is assumed that the vehicle accelerates during cranking start from the start of engine 1 to the completion of start, and the predicted motor rotation increase during cranking start accompanying the assumed vehicle acceleration Determine the quantity ΔNm. The target motor rotation speed Nmt is obtained by adding the predicted motor rotation increase amount ΔNm to the current motor rotation speed Nmo. When the crank mode start is assumed to start at the current motor operating point A during EV mode selection, the target motor speed Nmt is increased by increasing the motor speed Nm without lowering the motor output during cranking start. The position that has reached is assumed to be the predicted reaching operation point B. Then, the engine start determination is performed with the predicted reaching operation point B as the determination reference position.

That is, when the engine start determination is performed with the predicted reaching operation point B as the determination reference position, when there is an acceleration request during cranking start, the engine start determination is issued and cranking start of the engine 1 is started. To do. At this time, during cranking start, the target motor speed Nmt is reached by the increase in the motor speed Nm without reducing the motor output. Therefore, when there is an acceleration request during cranking start of the engine 1, it is possible to prevent a reduction in the driving force transmitted to the left and right drive wheels 9, 9.

In the first embodiment, when the engine start determination is performed, the position at which the target motor speed Nmt is reached by increasing the motor speed Nm while maintaining the motor torque Tm at the start of the cranking start is predicted arrival driving. Let it be point B.

That is, when the engine start determination is issued, the motor output increases when the predicted reaching operation point B is reached by keeping the motor torque Tm at the start of the start during cranking start. Therefore, when there is an acceleration request during cranking start of the engine 1, the driving force transmitted to the left and right drive wheels 9, 9 can be increased.

In the first embodiment, the motor torque obtained by subtracting the cranking torque necessary for cranking start of the engine 1 from the motor maximum torque at the predicted reaching operation point B is converted into the driving force of the left and right drive wheels 9 and 9 to achieve the predicted arrival. The driving force that can be realized at the operating point B is obtained. When the engine start determination is performed, the “EV mode” is maintained as long as the realizable driving force is greater than the target driving force, and when the realizable driving force is equal to or less than the target driving force, the engine start determination is issued.

In other words, by determining whether or not the engine has been started based on the driving force, the EV mode is maintained while the target driving force can be achieved with a margin, and when the target driving force can be achieved at the last minute, the engine A start determination is issued. Therefore, the target driving force at the start of starting can be secured as the driving force transmitted to the left and right drive wheels 9 and 9 during cranking start while securing the selection area of “EV mode”.

In Example 1, when the predicted motor rotation increase amount ΔNm is obtained, it is assumed that the vehicle accelerates when the driver depresses the accelerator and performs an operation while starting the engine.

That is, it is possible to prevent a decrease in the driving force transmitted to the left and right drive wheels 9 and 9 when starting and when there is a request for acceleration by depressing the accelerator during the cranking start.

In Example 1, when the predicted motor rotation increase amount ΔNm is obtained, the rotation increase map value ΔNmMAP is predicted based on the current vehicle speed VSP and the battery output Pout from the battery 12 connected to the motor generator 3.

That is, with respect to the vehicle speed VSP, when an operation is performed with the same accelerator depression amount, the motor rotation increase amount increases as the vehicle speed decreases, and the motor rotation increase decreases as the vehicle speed increases. On the other hand, regarding the battery output Pout, the motor rotation increase amount increases as the battery output Pout increases, and the motor rotation increase amount decreases as the battery output Pout decreases. Therefore, when determining the predicted motor rotation increase amount ΔNm, by determining the predicted motor rotation increase amount ΔNm based on the vehicle speed VSP and the battery output Pout, an appropriate predicted motor rotation increase amount ΔNm corresponding to the level of the vehicle speed VSP and the battery output Pout is set. Can do.

In the first embodiment, when the predicted motor rotation increase amount ΔNm is obtained, the predicted motor rotation increase amount ΔNm is higher as the vehicle speed VSP at the current time is lower, and the predicted motor rotation increase is higher when the current vehicle speed VSP is higher. The amount ΔNm is predicted to be low.

That is, with respect to the vehicle speed VSP, in the high vehicle speed range where the gear ratio of the belt type continuously variable transmission 6 is high, the drivability sensitivity of the pulling shock caused by the decrease in the driving force due to the decrease in the motor output is reduced. . For this reason, the EV range in the high vehicle speed range can be expanded by predicting the predicted motor rotation increase amount ΔNm to be lower as the vehicle speed VSP is higher. Therefore, when obtaining the predicted motor rotation increase amount ΔNm, the EV motor rotation increase amount ΔNm is predicted according to the vehicle speed VSP, thereby ensuring the widest possible EV range while minimizing the drivability sensitivity to pulling shocks. Can do.

In Example 1, when the predicted motor rotation increase amount ΔNm is obtained, the predicted motor rotation increase amount ΔNm is predicted to be lower as the road surface gradient of the traveling road surface is an uphill gradient.

That is, as for the road surface gradient, when the operation is performed with the same accelerator depression amount, the amount of increase in the motor rotation is lower as the slope is higher than the flat road. For this reason, by predicting the predicted motor rotation increase ΔNm to be lower as the road surface gradient is higher, the EV region during traveling on the uphill road can be expanded. Therefore, when the predicted motor rotation increase amount ΔNm is obtained, it is possible to expand the selection area of “EV mode” while traveling on the uphill road by predicting the predicted motor rotation increase amount ΔNm lower as the road surface gradient is higher. it can.

Next, the effect will be described.
In the control method and control apparatus for the FF hybrid vehicle in the first embodiment, the effects listed below can be obtained.

(1) An engine 1 and a motor (motor generator 3) are mounted as a drive source in a drive system from the drive source to the drive wheels 9 and 9. The operation mode includes an electric vehicle mode (EV mode) using a motor (motor generator 3) as a drive source, and a hybrid vehicle mode (HEV mode) using the engine 1 and the motor (motor generator 3) as drive sources.
When engine start determination is issued during the selection of the electric vehicle mode (EV mode), cranking start of the engine 1 is started using the motor (motor generator 3) as a start motor.
In this hybrid vehicle (FF hybrid vehicle) control method, it is assumed that the vehicle accelerates during cranking start from start of engine 1 to completion of start while selecting electric vehicle mode (EV mode), and assumed vehicle acceleration A predicted motor rotation increase amount ΔNm during cranking start associated with is obtained.
The target motor rotation speed Nmt is obtained by adding the predicted motor rotation increase amount ΔNm to the current motor rotation speed Nmo.
It is assumed that cranking start is started at the current motor operation point A during the selection of the electric vehicle mode (EV mode). At this time, the position at which the target motor speed Nmt is reached by increasing the motor speed Nm without lowering the motor output during cranking start is set as the predicted attainment operating point B, and the predicted attainment operating point B is set as the determination reference position. As shown in FIG.
Therefore, a control method for a hybrid vehicle (FF hybrid vehicle) is provided that prevents a reduction in driving force transmitted to the drive wheels (left and right drive wheels 9, 9) when there is an acceleration request during cranking start of the engine 1. can do.

(2) When engine start determination is performed, the position at which the target motor speed Nmt is reached by increasing the motor speed Nm while maintaining the motor torque Tm at the start of cranking is determined as the predicted reaching operation point B (FIG. 5).
For this reason, in addition to the effect of (1), when there is an acceleration request during cranking start of the engine 1, the driving force transmitted to the left and right drive wheels 9, 9 can be increased.

(3) By converting the motor torque obtained by subtracting the cranking torque necessary for cranking start of the engine 1 from the maximum motor torque at the predicted reaching operation point B into the driving force of the driving wheels (left and right driving wheels 9, 9). The driving force that can be realized at the predicted reaching operation point B is obtained.
When the engine start determination is performed, the electric vehicle mode (EV mode) is maintained as long as the realizable driving force is larger than the target driving force, and when the realizable driving force falls below the target driving force, the engine start determination is issued (FIG. 6). ).
Therefore, in addition to the effect of (2), when there is an acceleration request during cranking start, it is ensured that the driving force transmitted to the driving wheels (left and right driving wheels 9, 9) is increased in accordance with the acceleration request. Can do.

(4) When the predicted motor rotation increase amount ΔNm is obtained, it is assumed that the vehicle accelerates when the driver depresses the accelerator and performs an operation while the engine is started (FIG. 3).
For this reason, in addition to the effects of (1) to (3), when there is a request for acceleration by stepping on the accelerator while cranking is started, the driving force transmitted to the driving wheels (left and right driving wheels 9, 9) is reduced. Can be prevented.

(5) When obtaining the predicted motor rotation increase amount ΔNm, based on the current vehicle speed VSP and the battery output Pout from the battery 12 connected to the motor (motor generator 3), the predicted motor rotation increase amount ΔNm (rotation increase amount) Map value ΔNmMAP) is predicted (FIG. 4).
For this reason, in addition to the effect of (4), when the predicted motor rotation increase amount ΔNm is obtained, it can be set to an appropriate predicted rotation increase amount ΔNm according to the level of the vehicle speed VSP and the battery output Pout.

(6) When calculating the predicted motor rotation increase amount ΔNm, the lower the current vehicle speed VSP, the higher the predicted motor rotation increase amount ΔNm, and the higher the current vehicle speed VSP, the higher the predicted motor rotation increase amount ΔNm. Is predicted to be low (FIG. 3).
For this reason, in addition to the effect of (5), when determining the predicted motor rotation increase amount ΔNm, by predicting the predicted motor rotation increase amount ΔNm according to the vehicle speed VSP, EV The area can be secured as wide as possible.

(7) When the predicted motor rotation increase amount ΔNm is obtained, the predicted motor rotation increase amount ΔNm is predicted to be lower as the road surface gradient of the traveling road surface is an uphill gradient (FIG. 3).
For this reason, in addition to the effect of (5) or (6), when calculating the predicted motor rotation increase amount ΔNm, the predicted motor rotation increase amount ΔNm is predicted to be lower as the road surface gradient is higher, and the vehicle is traveling on an uphill road. The area for selecting the “EV mode” can be expanded.

(8) An engine 1 and a motor (motor generator 3) are mounted as a drive source in a drive system from the drive source to the drive wheels 9 and 9. The operation mode includes an electric vehicle mode (EV mode) using a motor (motor generator 3) as a drive source, and a hybrid vehicle mode (HEV mode) using the engine 1 and the motor (motor generator 3) as drive sources.
When engine start determination is issued during the selection of the electric vehicle mode (EV mode), a controller (integrated controller 14) for starting cranking start of the engine 1 using the motor (motor generator 3) as a start motor is provided.
In this hybrid vehicle (FF hybrid vehicle) control apparatus, the controller (integrated controller 14) accelerates the vehicle during the cranking start from the start of the engine 1 to the start completion while the electric vehicle mode (EV mode) is selected. Assuming that, a predicted motor rotation increase amount ΔNm during cranking start accompanying the assumed vehicle acceleration is obtained.
Assuming that cranking start is started at the current motor operating point A, the target motor rotational speed Nmt is obtained by adding the predicted motor rotational speed increase ΔNm to the current motor rotational speed Nm.
It is assumed that cranking start is started at the current motor operation point A during the selection of the electric vehicle mode (EV mode). At this time, the position at which the target motor speed Nmt is reached by increasing the motor speed Nm without lowering the motor output during cranking start is set as the predicted attainment operating point B, and the predicted attainment operating point B is set as the determination reference position. As shown in FIG.
Therefore, there is provided a control device for a hybrid vehicle (FF hybrid vehicle) that prevents a reduction in driving force transmitted to the driving wheels (left and right driving wheels 9, 9) when there is an acceleration request during cranking start of the engine 1. can do.

The hybrid vehicle control method and control device of the present disclosure have been described based on the first embodiment. However, the specific configuration is not limited to the first embodiment, and design changes and additions are permitted without departing from the gist of the invention according to each claim of the claims.

In the first embodiment, when the engine start determination is performed, the position at which the target motor speed Nmt is reached by increasing the motor speed Nm while maintaining the motor torque Tm at the start of the cranking start is predicted arrival driving. An example of point B is shown. However, when the engine start determination is performed, an example of determining the predicted reaching operation point by increasing the motor rotation speed along the motor output line during cranking start may be used. Further, when the engine start determination is performed, an example of determining the predicted attainment operation point by increasing the motor rotation speed with a rising slope from the motor torque at the start of the start during cranking start may be used. In short, any engine start determination may be made as long as the motor rotation speed Nm is increased without decreasing the motor output during cranking start.

In the first embodiment, the motor torque obtained by subtracting the cranking torque necessary for cranking start of the engine 1 from the motor maximum torque at the predicted reaching operation point B is converted into the driving force of the left and right drive wheels 9 and 9 to achieve the predicted arrival. The driving force that can be realized at the operating point B is obtained. And when performing engine start determination, while the drive force that can be realized is larger than the target drive force, the “EV mode” is maintained, and when the drive force that can be realized is less than or equal to the target drive force, the engine start determination is shown. . However, the engine start determination may be made when the motor torque margin that can be realized at the predicted reaching operation point is equal to or less than the cranking torque. The motor torque margin for the maximum torque curve characteristic of the motor is the value obtained by adding the engine torque to the cranking torque and the motor torque required to obtain the predicted motor rotation increase amount, and the EV → HEV switching line characteristic is set. It is good also as an example which performs engine starting determination. Further, a large number of EV → HEV switching line characteristics corresponding to acceleration during cranking start may be set according to vehicle speed, road surface gradient, battery output, and the like. When the EV → HEV switching line characteristic is set, the engine start determination is issued when the motor operating point crosses the EV → HEV switching line characteristic while the “EV mode” is selected.

In the first embodiment, an example in which the control method and the control device of the present disclosure are applied to an FF hybrid vehicle having a parallel hybrid drive system called a one-motor / two-clutch and having a belt type continuously variable transmission as a transmission. Indicated. However, the control method and control device of the present disclosure can be applied to various hybrid vehicles as long as the hybrid vehicle has “EV mode” and “HEV mode” and starts the engine using a motor as a driving source for traveling as a starter motor. Can be applied.

Claims (8)

1. In the drive system from the drive source to the drive wheel, an engine and a motor are mounted as the drive source,
   As an operation mode, an electric vehicle mode using the motor as a drive source, and a hybrid vehicle mode using the engine and the motor as a drive source,
   In the hybrid vehicle control method for starting cranking start of the engine using the motor as a start motor when engine start determination is issued during the selection of the electric vehicle mode,
   During the selection of the electric vehicle mode, assuming that the vehicle accelerates during cranking start from the start of the engine to the completion of start, obtain the predicted motor rotation increase amount during cranking start accompanying the assumed vehicle acceleration,
   By adding the predicted motor rotation increase amount to the current motor rotation number, a target motor rotation number is obtained,
   When the cranking start is assumed to start at the current motor operation point during the selection of the electric vehicle mode, the target motor rotation speed is increased by increasing the motor rotation speed without decreasing the motor output during cranking start. A control method for a hybrid vehicle, characterized in that an engine start determination is performed using a position that has reached the predicted arrival operating point as a predicted arrival operating point and the predicted reaching operating point as a determination reference position.
2. The hybrid vehicle control method according to claim 1, wherein:
   When performing the engine start determination, a position that has reached the target motor rotation number by increasing the motor rotation speed while maintaining the motor torque at the start of cranking start is set as a predicted reaching operation point. A control method for a hybrid vehicle.
3. In the control method of the hybrid vehicle described in Claim 2,
   Driving that can be realized at the predicted reaching operation point by converting the motor torque obtained by subtracting the cranking torque necessary for cranking start of the engine from the maximum motor torque at the predicted reaching operation point into the driving force of the driving wheel. Seeking power,
   When the engine start determination is performed, the electric vehicle mode is maintained as long as the realizable driving force is larger than the target driving force, and the engine start determination is issued when the realizable driving force is equal to or less than the target driving force. A control method of a hybrid vehicle characterized by the above.
4. In the control method of the hybrid vehicle as described in any one of Claim 1- Claim 3,
   The hybrid vehicle control method according to claim 1, wherein when the predicted motor rotation increase amount is obtained, it is assumed that the vehicle accelerates when a driver depresses an accelerator and performs an operation while the engine is started.
5. In the control method of the hybrid vehicle described in Claim 4,
   The method for controlling a hybrid vehicle, wherein when the predicted motor rotation increase amount is obtained, the predicted motor rotation increase amount is predicted based on a current vehicle speed and a battery output from a battery connected to the motor.
6. In the control method of the hybrid vehicle described in Claim 5,
   When calculating the predicted motor rotation increase amount, the predicted motor rotation increase amount is increased as the vehicle speed at the current time is lower, and the predicted motor rotation increase amount is predicted as the vehicle speed at the current time is higher. A control method of a hybrid vehicle characterized by the above.
7. In the hybrid vehicle control method according to claim 5 or 6,
   The method for controlling a hybrid vehicle, wherein when the predicted motor rotation increase amount is obtained, the predicted motor rotation increase amount is predicted to be lower as the road surface gradient of the traveling road surface is an uphill gradient.
8. In the drive system from the drive source to the drive wheel, an engine and a motor are mounted as the drive source,
   As an operation mode, an electric vehicle mode using the motor as a drive source, and a hybrid vehicle mode using the engine and the motor as a drive source,
   When an engine start determination is issued during the selection of the electric vehicle mode, a control device for a hybrid vehicle including a controller that starts cranking start of the engine using the motor as a start motor.
   The controller is
   During the selection of the electric vehicle mode, assuming that the vehicle accelerates during cranking start from the start of the engine to the completion of start, obtain the predicted motor rotation increase amount during cranking start accompanying the assumed vehicle acceleration,
   By adding the predicted motor rotation increase amount to the current motor rotation number, a target motor rotation number is obtained,
   Assuming that cranking start is started from the current motor operating point, when reaching the target motor rotational speed is predicted by increasing the motor rotational speed without decreasing the motor output during cranking starting, A control apparatus for a hybrid vehicle, wherein a control process for determining whether to start the engine is executed when the motor torque margin at the predicted reaching operation point corresponds to cranking torque.

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