WO2014171273A1

WO2014171273A1 - Clutch control device for hybrid vehicle

Info

Publication number: WO2014171273A1
Application number: PCT/JP2014/058314
Authority: WO
Inventors: 芦沢　裕之; 裕 ▲高▼村
Original assignee: 日産自動車株式会社
Priority date: 2013-04-18
Filing date: 2014-03-25
Publication date: 2014-10-23
Also published as: JP2016112900A

Abstract

When an engine (2) is started following an accelerator being stepped on, transmission torque capacity of a first clutch (3) is reduced, and transmission torque capacity of a second clutch (4) is increased, in accordance with an increase in engine rotational frequency.

Description

Clutch control device for hybrid vehicle

The present invention relates to a clutch control device for a hybrid vehicle.

Conventionally, a hybrid vehicle having a first clutch that interrupts torque transmission between the engine and the motor generator and a second clutch that interrupts torque transmission between the motor generator and the drive wheels is known.
Patent Document 1 discloses a first clutch torque capacity that is a cranking torque and a second clutch torque capacity that is a driving torque of a vehicle when the engine is started by connecting the first clutch as the driver depresses the accelerator. A technique for preventing the motor torque from exceeding the upper limit torque by distributing within the motor upper limit torque range is disclosed. At this time, the acceleration of the vehicle by the early engine start is achieved by increasing the distribution of the first clutch torque capacity as the driver's accelerator depression speed increases.

JP 2009-227277 JP

However, the above prior art has a problem that since the distribution of both clutch torque capacities is always constant while the engine is started, the acceleration is stagnant and the acceleration performance desired by the driver cannot be obtained.
An object of the present invention is to provide a clutch control device for a hybrid vehicle that can realize acceleration performance desired by a driver.

In the present invention, when starting the engine as the accelerator is depressed, the transmission torque capacity of the first clutch is decreased and the transmission torque capacity of the second clutch is increased in accordance with the increase in the engine speed.

Therefore, in the present invention, the driving torque of the vehicle increases with the increase of the engine speed, so that the stagnation of acceleration can be suppressed and the acceleration performance desired by the driver can be realized.

1 is a system diagram of a hybrid vehicle to which a clutch control device of Embodiment 1 is applied. 4 is a flowchart showing processing contents of an integrated controller 13. It is a drive torque command value calculation map according to a vehicle speed and an accelerator opening. (a) Clutch torque capacity-clutch oil pressure conversion map, (b) Clutch oil pressure-current conversion map. It is a flowchart which shows the 2nd clutch control mode setting method. (a) Second clutch slip rotation speed target value calculation map based on basic second clutch torque capacity command value and second clutch oil temperature, (b) Second clutch slip rotation speed target value calculation based on engine start distribution motor torque It is. It is a block diagram of the feedback control for 2nd clutches. It is a flowchart which shows the torque capacity command value calculation method of each clutch during engine starting. It is an engine start lower limit torque calculation map. It is a motor upper limit torque calculation map. In the conventional clutch control apparatus, it is a time chart when changing from EV running to HEV running as the driver depresses the accelerator. In Example 1, it is a time chart when changing from EV driving | running | working to HEV driving | running | working with a driver | operator's accelerator depression.

1 Motor generator
2 Engine
3 First clutch
4 Second clutch
5 Transmission
6 Second clutch input shaft speed sensor
7 Second clutch output shaft speed sensor
9 High voltage battery
10 Acceleration position sensor
11 Engine speed sensor
12 Clutch oil temperature sensor
13 Integrated controller
14 Transmission controller
15 Clutch controller
16 Engine controller
17 Motor controller
18 Battery controller
19 Final gear
20a, 20b Left and right drive shaft
21a, 21b Left and right drive wheels
22 Communication line

[Example 1]
[Overall system]
FIG. 1 is a system diagram of a hybrid vehicle to which the clutch control device of the first embodiment is applied.
A motor generator (hereinafter referred to as a motor) 1 is an AC synchronous motor that drives left and

right drive wheels

21a and 21b by drive torque control and recovers vehicle kinetic energy to the high-voltage battery 9 by engine start and regenerative brake control. .
The engine 2 is capable of lean combustion, and the engine torque is controlled to coincide with 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.
The first clutch 3 is a dry clutch, and engages / releases between the engine 2 and the motor 1. When the first clutch 3 is in the fully engaged state, the motor torque + engine torque is transmitted to the second clutch 4, and when the first clutch 3 is in the released state, only the motor torque is transmitted to the second clutch 4.
The second clutch 4 is a wet clutch, and generates transmission torque (clutch torque capacity) according to clutch hydraulic pressure (pressing force). The transmission torque of the second clutch 4 is transmitted to the left and

right drive shafts

20a and 20b via the transmission 5 and the final gear 19 from the motor 1 and the engine 2 (when the first clutch is engaged). The

The transmission 5 is a stepped transmission and includes a plurality of planetary gears. Shifting is performed by changing the force transmission path by engaging / disengaging the clutch and brake inside the transmission.
The second clutch input shaft (motor) speed sensor 6 detects the current input speed of the second clutch 4.
The second clutch output shaft rotational speed sensor 7 detects the current output shaft rotational speed of the second clutch 4.
A high voltage inverter (hereinafter referred to as an inverter) 8 generates a drive current for the motor 1 by performing DC-AC conversion.
A high voltage battery (hereinafter referred to as a battery) 9 stores regenerative energy from the motor 1.
The accelerator position sensor 10 detects the accelerator opening.
The engine speed sensor (engine speed detection means) 11 detects the current engine speed.
The clutch oil temperature sensor 12 detects the oil temperature of the second clutch 4.

The integrated controller 13 calculates a drive torque command value from the battery state, the accelerator opening, and the vehicle speed (a value synchronized with the transmission output shaft speed). Based on the result, command values for the actuators (motor 1, engine 2, first clutch 3, second clutch 4 and transmission 5) are calculated and transmitted to the controllers 14-17. The integrated controller 13 disconnects the first clutch 3 and travels by the torque of the motor generator 1. From the EV (electric vehicle) mode, the integrated controller 13 connects the first clutch 3 and travels by the torque of the engine 2 and the motor generator 1 (hybrid). When switching to (mode), the engine 2 is started using the torque of the motor generator 1 (engine starting means).
The transmission controller 14 performs shift control so as to achieve the shift command from the integrated controller 13.
The clutch controller 15 controls the current of the solenoid valve so as to realize a clutch hydraulic pressure (current) command value for each clutch hydraulic pressure command value from the integrated controller 13.
The engine controller 16 performs engine torque control so as to achieve the engine torque command value from the integrated controller 13.
The motor controller 17 performs motor torque control so that the motor torque command value from the integrated controller 13 is achieved.
The battery controller 18 manages the state of charge of the battery 9 and transmits the information to the integrated controller 13.
Communication between the controllers 13 to 18 is performed via the communication line 22.

[Control of integrated controller]
FIG. 2 is a flowchart showing the processing contents of the integrated controller 13. This processing content is executed at a constant sampling cycle.
In step S1, the battery charge SOC, the shift position of the transmission 5, the input / output shaft rotational speed ω _cl2i , ω _o engine rotational speed ω _{e of} the second clutch 4, the engine operating state E _sts , the vehicle speed Vsp, etc. The vehicle state measured by the controller is received.
In step S2, the accelerator opening Apo is measured from the accelerator position sensor 10.
In step S3 (drive torque command value calculating means), a drive torque command value T _d ^* is calculated from the accelerator opening Apo and the vehicle speed Vsp. In the first embodiment, for example, calculation is performed with reference to a driving torque command value calculation map corresponding to the vehicle speed Vsp and the accelerator opening Apo as shown in FIG. In FIG. 3, the drive torque command value T _d ^* is set so as to increase as the accelerator opening Apo increases, and to decrease as the vehicle speed Vsp increases.

In step S4, the first clutch control mode is set (setting of the first clutch mode flag fCL1) from the vehicle state such as the battery charge amount SOC, the drive torque command value T _d ^*, and the vehicle speed Vsp. Although the details are omitted here, for example, in a driving scene where the efficiency of the engine 2 is relatively low, such as starting at low acceleration, the motor runs alone (EV mode), so the first clutch 3 is released (fCL1 = 0) If the vehicle is suddenly accelerated or the battery charge SOC is less than the predetermined value SOC _th1 or the vehicle speed Vsp is greater than or equal to the predetermined value Vsp _th1 (the motor rotation speed exceeds the allowable rotation speed), EV driving is difficult. The first clutch 3 is engaged (fCL1 = 1) to travel with the motor 2 and the motor 1 (HEV mode).
In step S5, the second clutch control mode CL2MODE (engaged, released, slip) is set from the vehicle state such as the battery charge amount SOC, the drive torque command value _Td ^* , the first clutch control mode flag fCL1, and the vehicle speed Vsp. The method for setting the second clutch control mode will be described later.

In step S6, the driving torque command value T _d ^* the basic engine torque command value T _{E_base} on the basis of the control mode and the vehicle states of the clutches ^*, allocated to the basic motor torque command value _T m_base ^*. Various methods can be considered for the allocation method, but the details are omitted.
In step S7 (transmission torque capacity distribution means), the torque capacity command value T _{cl1_ENG_START} of each clutch during engine start is determined from the control mode of each clutch, the engine speed ω _e , the drive torque command value T _d ^*, and various vehicle states. T _{cl2_ENG_START} is calculated. A detailed calculation method will be described later.
In step S8, determining a first clutch control mode flag fCL1, the second clutch input rotational speed .omega.c _L2I, and whether or not the engine starting from the engine rotational speed omega _e. Actually, when the first clutch control mode is the engagement mode and the engine speed is lower than the second clutch input speed, it is determined that the engine is starting and the start flag fENG_ST is set. It is judged that there is no and the flag is cleared.
In step S9, it is determined whether or not the slip rotation speed control of the second clutch 4 is to be executed. When the second clutch 4 is set in the slip state in S5 and the absolute value of the actual slip rotation speed (input shaft-output shaft) exceeds a predetermined value, the slip rotation speed control is turned ON and the process proceeds to step S10. If it is set to open or engaged, the rotational speed control is turned OFF and the process proceeds to step S14.

In step S10, a basic second clutch torque capacity command value _{Tcl2_base} ^* is calculated. Here, for example, it is the same value as the drive torque command value T _d ^* .
In step S11, the input shaft rotation is determined from the first clutch control mode flag fCL1, the basic second clutch torque capacity command value T _{cl2_base} ^* , the second clutch oil temperature Temp _cl2 , the battery charge SOC, and the output shaft rotational speed measurement value ω _o. The numerical target value ω _cl2i ^* is calculated. A detailed calculation method will be described later.
In step S12, the rotational speed control motor torque command value _{Tm_FB_ON} is calculated so that the input rotational speed target value _ωcl2i ^* and the input rotational speed measured value _ωcl2i coincide. There are various calculation (control) methods. For example, calculation is performed based on the following formula (PI control). The actual calculation is calculated using a recurrence formula obtained by discretization by Tustin approximation or the like.

However,
K _Pm : Motor control proportional gain K _Im : Motor control integral gain s: Differential operator

In step S13, the basic second clutch torque capacity command value _T cl2_base ^* a second clutch torque capacity command value T _{Cl_FB_ON} rotation speed control from the rotational speed control motor torque command value T _{M_FB_ON} and the engine torque command value _T e_base ^* calculation To do. A detailed calculation method will be described later.
In step S14, an internal state variable for calculating the above-described rotational speed control motor torque command value _{Tm_FB_ON} and the rotational speed control second clutch torque capacity command value _{Tcl_FB_ON} is initialized.
In step S15, a clutch torque capacity command value _{Tcl2_FB_OFF} is calculated when the rotational speed control is not performed, that is, until the second clutch 4 is engaged / disengaged or engaged from the engaged state to the rotational speed control (slip state).
1. When fastening (1) If T _{cl2_zl} ^* <T _d ^* × K _safe T _{cl2_FB_OFF} = T _{cl2_zl} ^* + ΔT _cl2LU … (2)
(2) If T _{cl2_zl} ^* ≧ T _d ^* × K _safe , T _{cl2_FB_OFF} = T _d ^* × K _safe … (3)
2. To open T _{cl2_FB_OFF} = 0 (4)
3. When the second clutch is engaged → slipped T _{cl2_FB_OFF} = T _{cl2_zl} ^* -ΔT _cl2slp … (5)
However,
K _safe : Second clutch safety factor (> 1)
ΔT _cl2LU : Slip (or release) → Torque capacity change rate at the time of fastening transition ΔT _cl2slp : Torque capacity change rate at the time of fastening → slip transition
T _{cl2_zl} ^* : Last value of the last second torque command value

In step S16, the final second clutch torque capacity command value _Tcl2 ^* is determined based on the following conditions.
1. During slip rotation speed control,
(1) When the engine is starting (fENG_ST = 1) T _cl2 ^* = T _{cl2_ENG_START} … (6)
(2) Other than above T _cl2 ^* = T _{cl2_FB_ON} … (7)
2. When slip speed control is stopped T _cl2 ^* = T _{cl2_FB_OFF} … (8)

In step S17, it determines a first clutch torque capacity command value T _CL1 ^* on the basis of the first clutch control mode flag fCL1.
1. When the first clutch control mode is the engagement mode,
(1) When the engine is starting (fENG_ST = 1) T _CL1 ^* = T _{cl1_ENG_START} … (9)
(2) Other than above T _CL1 ^* = T _{cl1_max} … (10)
However,
T _{cl1_max} : Maximum torque capacity of the first clutch 2. When the first clutch control mode is the disengagement mode T _CL1 ^* = 0 (11)

In step S18, current command values I _CL1 ^* and I _CL2 ^* are calculated from the clutch torque capacity command values T _CL1 ^* and T _CL2 ^* . Actually, it is calculated with reference to the clutch torque capacity-clutch oil pressure conversion map shown in FIG. 4A and the clutch oil pressure-current conversion map shown in FIG. Thereby, even when the clutch torque capacity has a non-linear characteristic with respect to the hydraulic pressure or current, the control target can be regarded as linear, and thus the linear control theory as described above can be applied.
In step S19, a final motor torque command value T _m ^* is determined based on the following conditions.
1. When slip rotation speed control is in progress T _m ^* = T _{m_FB_ON} (12)
2. When slip speed control is stopped T _m ^* = T _{m_base} (13)
In step S20, the calculated command value is transmitted to each control controller.

[Second clutch control mode setting process]
FIG. 5 is a flowchart showing a second clutch control mode setting method. The control mode CL2MODE of the second clutch 4 is set from the vehicle state such as the battery charge amount SOC, the drive torque command value T _d ^* , the first clutch control mode flag fCL1 and the vehicle speed Vsp.
In step S51, the first clutch control mode is determined. When the first clutch control mode is engaged (engine start) (fCL1 = 1), the process proceeds to step S55. When the first clutch control mode is the release mode (engine stop) (fCL1 = 0), the process proceeds to step S52.
In step S52, it is determined whether or not the vehicle speed Vsp is zero (stop). If it is stopped, the process proceeds to step S53, and otherwise, the process proceeds to step S54.
In step S53, the second clutch control mode is set to the engagement mode (CL2MODE = 1).
In step S54, the second clutch control mode is set to the slip mode (CL2MODE = 2).
In step S55, it is determined whether or not the vehicle speed Vsp is higher than a predetermined value Vth1 (for example, the lowest vehicle speed at which the engine can be started). When it is low, the process proceeds to step S56, and when it is high, the process proceeds to step S58.

In step S56, the sign of the drive torque command value T _d ^* is determined. If the value is positive, the process proceeds to step S54. If the value is negative, the process proceeds to step S57.
In step S57, the second clutch control mode is set to the release mode (CL2MODE = 0).
In step S58, it is determined whether or not the previous second clutch control mode is the engagement mode. In the case of the fastening mode, the process proceeds to step S53, and in other cases, the process proceeds to step S59.
In step S59, it is determined from the engine speed measurement value ω _e , the second clutch slip rotation speed measurement value ω _cl2slp , and the slip rotation speed threshold value ω _cl2slpth whether or not the slip continuation condition is satisfied. When the slip continuation condition is satisfied, the process proceeds to step S54 to start or continue the slip, and when not satisfied, the process proceeds to step S53 to end the slip and shift to the fastening mode. The slip continuation conditions are as follows.
ω _e ≠ ω _cl2i (1st clutch disengagement or slip), or ω _cl2slp > ω _cl2slpth

[Input rotation speed target value calculation]
Next, details of a method of calculating the input rotation speed target value ω _cl2i ^* will be described.
First, the second clutch slip rotation speed target value ω _{cl2_slp} ^* is calculated based on the following.
1.In EV mode (fCL1 = 0)
ω _{cl2_slp} ^* = f _{cl2_slp_cl1OP} (T _{cl2_base} ^* , Temp _cl2 )… (14)
Here, f _{cl2_slp_cl1OP} () is a function having the basic second clutch torque capacity command value T _{cl2_base} ^* and the second clutch oil temperature Temp _cl2 as inputs. Actually, for example, the second clutch slip rotational speed target value calculation map based on the basic second clutch torque capacity command value T _{cl2_base} ^* and the second clutch oil temperature Temp _cl2 as shown in FIG. . As shown in FIG. 6 (a), the second clutch slip rotational speed target value ω _{cl2_slp} ^* in the EV mode is set so as to decrease as the second clutch oil temperature Temp _cl2 increases, and the basic second clutch torque capacity command is set. _{Set the} value T _{cl2_base} ^* to be smaller as it is larger. When the oil temperature of the second clutch 4 is “high” or “the clutch capacity command value is large”, the second clutch slip rotation speed target value ω _{cl2_slp} ^* is reduced to prevent the clutch oil temperature from rising. it can.

2. When engine torque is starting ω _{cl2_slp} ^* = f _{cl2_slp_cl1OP} (T _{cl2_base} ^* , Temp _cl2 ) + f _{cl2_Δωslp} (T _{eng_start} )… (15)
Here, f _{cl2_slp_cl1OP} () is a function for calculating the amount of increase in slip rotation speed at the time of engine start, and the engine start distribution motor torque T _{eng_start} is input. Actually, for example, a second clutch slip rotation speed target value calculation map based on the engine start distribution motor torque _{Teng_start} as shown in FIG. 6B is used. As shown in FIG. 6 (b), the second clutch slip rotational speed target value _{ωcl2_slp} ^* during engine torque start is set to increase as the engine start distribution motor torque _{Teng_start} decreases. As a result, the disturbance from the first clutch 3 cannot be completely cancelled, and even if the rotational speed decreases, sudden engagement can be prevented, and as a result, the engine 2 can be operated without any acceleration fluctuation. Can start.
If slip control is to be continued even after the engine is started, the slip rotation speed is the same as during EV travel (the increment is not added).

Next, the input rotational speed target value ω _cl2i ^* is calculated from the slip rotational speed target value ω _{cl2_slp} ^* and the output shaft rotational speed measured value ω _o based on the following equation.
ω _cl2i ^* = ω _{cl2_slp} ^* + ω _o … (16)
Finally, the upper and lower limits are applied to the input rotational speed target value ω _cl2i ^* calculated from the above equation to _obtain the final input shaft rotational speed target value. The upper and lower limit values are the upper and lower limit values of the engine speed.

[Second clutch torque capacity command value calculation for speed control]
Next, the details of the calculation method of the second clutch torque capacity command value T _{cl_FB_ON} for rotation speed control will be described.
FIG. 7 is a block diagram of feedback control for the second clutch. This control system is designed with a two-degree-of-freedom control method consisting of feedforward (F / F) compensation and feedback (F / B) compensation. Various design methods can be considered for the F / B compensator, but this time PI control is an example. Hereinafter, the calculation method will be described.
First, phase compensation is applied to the basic second clutch torque capacity command value T _{cl2_base} ^* based on the phase compensation filter G _FF (s) shown in the following formula, and the F / F second clutch torque capacity command value T _{cl2_base} ^* is obtained. Calculate. The actual calculation is calculated using a recurrence formula obtained by discretization by Tustin approximation or the like.

However,
τ _cl2 : Clutch model time constant τ _{cl2_ref} : _Reference response time constant for clutch control

Next, the second clutch torque capacity target value _{Tcl2_t} is calculated based on the following.
1. In EV mode T _{cl2_t} = T _{cl2_base} ^* … (18)
2. In HEV mode (1st clutch is engaged) T _{cl2_t} = T _{cl2_base} ^* -T _{e_est} (19)
Note that the second clutch torque capacity target value in the HEV mode means the capacity of the motor with respect to the torque capacity of the whole (engine 2 and motor 1).
_{Te_est} is an estimated engine torque value, and is calculated based on the following equation, for example.

However,
τ _e : Engine primary delay time constant
L _e : Engine dead time

Next, the second clutch torque capacity reference value _{Tcl2_ref} is calculated based on the following equation.

Next, the F / B second clutch capacity command value _{Tcl2_FB} is calculated from the second clutch torque capacity reference value _{Tcl2_ref} and the above-described rotation speed control motor torque command value _{Tm_FB_ON} based on the following equation.

However,
K _Pcl2 : Proportional gain for second clutch control
K _Icl2 : 2nd clutch control integral gain

Further, by considering the torque (inert torque) generated by the change in the input rotational speed as in the following equation, the torque capacity can be accurately controlled even when the input rotational speed is changing.

Here, T _{Icl2_eST} is an inertia torque estimated value, and is obtained, for example, by multiplying the input rotation speed change amount (differential value) by the moment of inertia around the input shaft.
Then, the F / F second clutch torque capacity command value T _{cl2_FF} and the F / B second clutch capacity command value T _{cl2_FB} are added to calculate the final second clutch capacity command value T _{cl2_FB_ON} for rotational speed control.

[Torque capacity command value calculation]
Next, details of a calculation method of the torque capacity command values T _{cl1_ENG_START} and T _{cl2_ENG_START} of each clutch during engine start will be described. FIG. 8 is a flowchart showing a torque capacity command value calculation method for each clutch during engine start.
In step S71, it is determined whether or not the first clutch control mode is the disengagement mode. If it is not the release mode (if it is the fastening mode), the process proceeds to step S72, and if it is the release mode, the process is terminated.
In step S72 (engine start lower limit torque calculating means), the engine start lower limit torque T required for cranking at the current engine speed from the engine speed ω _e and the engine operating state E _sts (whether or not after the first explosion) is determined. _{Calculate ENG_START} . Actually, before the first explosion, an engine start lower limit torque calculation map (see FIG. 9) created with a value obtained by adding an amount necessary for increasing the engine rotation to the engine friction torque for each rotation speed obtained in advance through experiments or the like. Use to calculate. Further, after the first explosion, the value is obtained by subtracting the torque output by the engine itself from the torque required for the engine start to be completed within a predetermined time (up to the second clutch input rotational speed).

In step S73 (motor upper limit torque calculating means), the motor upper limit torque T _{m_HLMT} is calculated from the battery charge SOC (or terminal voltage V _B ) and the input shaft speed ω _cl2i . Actually, for example, calculation is performed using a motor upper limit torque calculation map as shown in FIG.
In step S74 (second clutch torque capacity upper limit calculating means), the second clutch torque capacity upper limit T _{cl2_ENG_START_HLMT} is calculated from the engine start lower limit torque T _{ENG_START} and the motor upper limit torque T _{m_HLMT} using the following equation.
T _{cl2_ENG_START_HLMT} = T _{m_HLMT} -T _{ENG_START} … (24)
In step S75, the second clutch torque capacity command value for engine starting T _{cl2_ENG_START} is determined based on the following from the second clutch torque capacity upper limit value T _{cl2_ENG_START_HLMT} and the drive torque command value T _d ^* .
1. When T _d ^* > T _{cl2_ENG_START_HLMT} T _{cl2_ENG_START} = T _{cl2_ENG_START_HLMT}
2.When T _d ^* ≤ T _{cl2_ENG_START_HLMT} T _{cl2_ENG_START} = T _d ^*
In step S76, the engine starting first clutch torque capacity command value _{Tcl1_ENG_START} is calculated from the motor upper limit torque _{Tm_HLMT} and the engine starting second clutch torque capacity command value _{Tcl2_ENG_START} based on the following equation.
T _{cl1_ENG_START} = T _{m_HLMT} -T _{cl2_ENG_START} … (25)

Next, the operation will be described.
[Torque capacity command value calculation]
FIG. 11 is a time chart when the conventional clutch control device shifts from EV traveling to HEV traveling as the driver depresses the accelerator.
In the prior art, since the torque capacity command value of each clutch during engine start is constant, the second clutch torque capacity, which is the vehicle drive torque, remains unchanged during engine start, resulting in a deviation from the drive torque command value. Yes. As a result, the acceleration is stagnated and the acceleration performance desired by the driver cannot be obtained.
On the other hand, in the first embodiment, all of the remaining values (the second clutch torque capacity upper limit value T) _obtained by removing the engine start lower limit torque T _{ENG_START} required for engine start from the motor upper limit torque T _{m_HLMT} that is the torque that can be output by the motor 1. the _{Cl2_ENG_START_HLMT)} a second clutch torque capacity command value T _{Cl2_ENG_START} for starting the engine, the first clutch torque capacity command value for a value obtained by subtracting the second clutch torque capacity command value T _{Cl2_ENG_START} for starting the engine from the motor upper limit torque T _{M_HLMT} engine start T _{cl1_ENG_START} .

Here, as shown in FIG. 9, the engine start lower limit torque T _{ENG_START decreases} as the engine speed ω _e increases. In particular, since the engine itself generates combustion torque after the first engine explosion, the cranking torque required for starting the engine is smaller than that before the first explosion. On the other hand, the motor upper limit torque T _{M_HLMT,} as shown in FIG. 10, the engine speed omega _e regions of high, although the smaller the engine rotational speed omega _e becomes higher, the engine rotational speed such as during engine start omega _e It is constant in the low region. That is, the second clutch torque capacity upper limit value _{Tcl2_ENG_START_HLMT increases} as the engine speed ω _e increases. That is, in Example 1, when starting the engine 2 with the accelerator pedal depression, depending on the increase in the engine rotational speed omega _e while decreasing the first clutch torque capacity command value T _{Cl1_ENG_START} for starting the engine, the second engine starting The clutch torque capacity command value _{Tcl2_ENG_START} is increased.

As a result, it is possible to increase the drive torque of the vehicle immediately after depressing by making the maximum use of the motor torque while limiting the sum of the first clutch torque capacity and the second clutch torque capacity to the motor upper limit torque _{Tm_HLMT.} . FIG. 12 is a time chart when the vehicle travels from EV traveling to HEV traveling as the driver depresses the accelerator in the first embodiment. In the first embodiment, as shown in FIG. It is possible to make the driving torque coincide with the driving torque command value T _d ^* before the completion of engine start. Therefore, the acceleration stagnation can be significantly improved with respect to the above-described conventional technology, and the acceleration performance desired by the driver can be realized.
At this time, in Example 1, since the lower limit of the first clutch torque capacity is limited by the engine start lower limit torque T _{ENG_START} , the first clutch torque capacity decreases as the engine speed ω _e increases. Since the minimum cranking torque necessary for starting can be ensured, the engine 2 can be reliably started within a predetermined time.

As described above, Example 1 has the following effects.
(1) Engine 2, motor generator 1, first clutch 3 for intermittent torque transmission between engine 2 and motor generator 1, and second clutch for intermittent torque transmission between motor generator 1 and drive

wheels

21a, 21b 4 and the electric vehicle mode in which the first clutch 3 is disconnected and travels with the torque of the motor generator 1 to the hybrid mode in which the first clutch 3 is connected and the engine 2 and the motor generator 1 travel with the torque. An integrated controller 13 for starting the engine 2 using the torque of the generator 1, an engine speed sensor 11 for detecting the engine speed ω _e , and a motor upper limit torque calculating means for calculating the motor upper limit torque T _{m_HLMT} (step S73) If, when starting the engine 2 with the accelerator depression, the within the motor upper limit torque _T m_HLMT 1 It includes a transmission torque capacity allocation means for allocating a latch torque capacity and the second clutch torque capacity (step S7), and the transmission torque capacity allocation means, when starting the engine 2 with the accelerator depression, engine speed omega _e As the engine speed increases, the first clutch torque capacity is decreased and the second clutch torque capacity is increased.
Therefore, since the driving torque of the vehicle increases as the engine speed ω _e increases, acceleration stagnation can be suppressed and the acceleration performance desired by the driver can be realized.

(2) Engine start lower limit torque calculation means (step S72) that calculates the engine start lower limit torque T _{ENG_START} required for engine start based on the engine speed ω _e and whether or not the engine is after the first _explosion. The distribution means limits the lower limit of the first clutch torque capacity with the engine start lower limit torque T _{ENG_START} .
Therefore, the engine 2 can be reliably started while suppressing the stagnation of acceleration.

(3) and the drive torque command value calculating means for calculating a driving torque command value T _d ^* based on the accelerator opening degree (step S3), and the motor upper limit torque T _{M_HLMT} by subtracting the engine starting limit torque T _{ENG_START,} during engine start 2nd clutch torque capacity upper limit value calculating means (step S74) for calculating a second clutch torque capacity upper limit value _{Tcl2_ENG_START_HLMT} that can be distributed to the second clutch 4, and the transmission torque capacity distributing means is a drive torque command value. The value _obtained by limiting the upper limit of T _d ^* with the second clutch torque capacity upper limit value T _{cl2_ENG_START_HLMT} is defined as the second clutch torque capacity, and the value obtained by subtracting the second clutch torque capacity from the motor upper limit torque T _{m_HLMT is} defined as the first clutch torque capacity. To do.
Therefore, since the driving torque desired by the driver can be realized while the engine 2 is reliably started within the range of the motor upper limit torque _{Tm_HLMT} , the motor torque can be utilized to the maximum and the acceleration performance is improved.

(Other examples)
As mentioned above, although the form for implementing this invention was demonstrated based on the Example, the concrete structure of this invention is not limited to an Example, The design change of the range which does not deviate from the summary of invention And the like are included in the present invention.

Claims

Engine,
A motor generator;
A first clutch for intermittently transmitting torque between the engine and the motor generator;
A second clutch for intermittently transmitting torque between the motor generator and the drive wheel;
When switching from the electric vehicle mode in which the first clutch is disengaged and traveling by the torque of the motor generator to the hybrid mode in which the first clutch is engaged and the engine and the motor generator are traveled, the torque of the motor generator Engine starting means for starting the engine using
An engine speed detecting means for detecting the engine speed;
Motor upper torque calculating means for calculating the motor upper torque;
Transmission torque capacity distribution means for distributing the transmission torque capacity of the first clutch and the transmission torque capacity of the second clutch within the range of the motor upper limit torque when the engine is started as the accelerator is depressed;
With
The transmission torque capacity distribution means reduces the transmission torque capacity of the first clutch according to an increase in the engine speed and reduces the transmission torque capacity of the second clutch when the engine is started as the accelerator is depressed. A clutch control device for a hybrid vehicle, characterized by being increased.
The clutch control apparatus for a hybrid vehicle according to claim 1,
Engine starting lower limit torque calculating means for calculating an engine starting lower limit torque required for starting the engine based on whether the engine speed and the engine are after the first explosion,
The clutch control device for a hybrid vehicle, wherein the transmission torque capacity distribution means limits a lower limit of the transmission torque capacity of the first clutch with the engine start lower limit torque.
The clutch control device for a hybrid vehicle according to claim 2,
Driving torque command value calculating means for calculating a driving torque command value based on the accelerator opening;
Second clutch torque capacity upper limit calculating means for subtracting the engine start lower limit torque from the motor upper limit torque and calculating a second clutch torque capacity upper limit value that can be distributed to the second clutch during engine startup;
With
The transmission torque capacity distribution means sets a value obtained by limiting an upper limit of the drive torque command value with the second clutch torque capacity upper limit value as a transfer torque capacity of the second clutch, and transmits the second clutch from the motor upper limit torque. A clutch control device for a hybrid vehicle, wherein a value obtained by subtracting the torque capacity is set as a transmission torque capacity of the first clutch.