JP2010111144A - Controller for hybrid vehicle - Google Patents

Abstract

The present invention provides a control device for a hybrid vehicle capable of speeding up engine start when switching from an electric vehicle mode to an engine start mode and reliably preventing G from being lost.
A first clutch CL1 for intermittently connecting an engine Eng and a motor generator MG, and a second clutch CL2 for intermittently connecting a motor generator MG and left and right rear wheels RL, RR. ”And“ engine start mode ”. After switching from “EV mode” to “engine start mode”, the torque capacity command value for the second clutch CL2 is kept constant at a value equal to or greater than the EV drive torque phase immediately before the mode change, and slippage of the second clutch CL2 is detected. Until this time, the motor torque command value to the motor generator MG is gradually increased, and when the slip is detected, the first clutch CL1 is shifted to the engagement side to start the engine Eng (FIG. 2).
[Selection] Figure 1

Description

  The present invention relates to a control device for a hybrid vehicle that starts an engine using a motor generator that is a driving source for traveling in the electric vehicle mode when the mode is changed from the electric vehicle mode to the hybrid vehicle mode.

Conventionally, as a method for starting an engine of a hybrid vehicle having an engine, a first clutch, a motor generator, and a second clutch in a drive system, the engine is started when the driver depresses an accelerator pedal while driving with only the power of the motor generator. Simultaneously with the start request, the torque capacity command value for the second clutch is reduced from the maximum value to the electric vehicle drive torque phase equivalent value immediately before the engine start request, and then further reduced until the second clutch does not slip. . When it is detected that the second clutch is in the slip state, switching to motor rotation speed control is performed to increase the slip rotation speed, and after the slip rotation speed becomes sufficiently large, the first clutch is semi-engaged to crank the engine. To do. As a result, it is known that a second clutch is used to shut off a shock associated with engine start, thereby realizing a smooth engine start (see, for example, Patent Document 1).
JP 2006-306209 A

  However, in the conventional hybrid vehicle control device, when the hydraulic response delay of the torque capacity (engaged hydraulic pressure) of the second clutch is large, the second clutch is in a slip state compared to the case where the hydraulic response delay is small. The timing for detecting this is delayed. As a result, the engine start is delayed and the torque capacity command value for the second clutch is excessively lowered, so that the acceleration immediately before the engine start request cannot be maintained, and so-called G is lost. was there.

  The present invention has been made paying attention to the above-mentioned problem. When switching from the electric vehicle mode to the engine start mode, the engine start can be accelerated and the hybrid vehicle control device can surely prevent the G dropout. The purpose is to provide.

In order to achieve the above object, a control apparatus for a hybrid vehicle of the present invention includes a first clutch that connects and disconnects an engine and a motor generator, and a second clutch that connects and disconnects the motor generator and a drive wheel. A hybrid vehicle mode in which the first clutch is engaged and the engine and the motor generator are driven, an electric vehicle mode in which the first clutch is released and only the motor generator is driven; The vehicle travels while switching between an engine start mode in which engine cranking is performed using the power of the same motor generator while traveling only with power.
Then, after switching from the electric vehicle mode to the engine start mode, the torque capacity command value to the second clutch is made constant at a value equal to or greater than the electric vehicle driving torque phase immediately before the mode switching, and the slip of the second clutch An engine start control means is provided for gradually increasing the motor torque command value to the motor generator until the engine is detected, and when the slip is detected, the first clutch is shifted to the engagement side to start the engine.

Therefore, in the hybrid vehicle control device of the present invention, after switching from the electric vehicle mode to the engine start mode, in the engine start control means, the torque capacity command value to the second clutch is the electric vehicle immediately before the mode switch. It is constant at a value equal to or greater than the driving torque phase. Then, the motor torque command value to the motor generator is gradually increased until the slip of the second clutch is detected. When the slip is detected, the first clutch is shifted to the engagement side and the engine is started.
That is, as compared with the hydraulic control type second clutch, the second clutch is slipped by an increase in the motor torque that can be regarded as having a quick response and almost no response delay. For this reason, the time required from the engine start request to the slip detection is shortened as compared with the case of causing the slip by the lowering control of the second clutch hydraulic pressure. In addition, since the torque capacity command value for the second clutch is not reduced more than necessary, the vehicle acceleration is ensured to be equal to or higher than the acceleration immediately before the engine start request.
As a result, when the electric vehicle mode is switched to the engine start mode, the engine start can be accelerated and the G omission can be reliably prevented.

  Hereinafter, the best mode for realizing a control device for a hybrid vehicle of the present invention will be described based on a first embodiment shown in the drawings.

First, the configuration will be described.
FIG. 1 is an overall system diagram showing a parallel type FR hybrid vehicle (an example of a hybrid vehicle) by rear wheel drive to which the control device of the first embodiment is applied.

  As shown in FIG. 1, the drive system of the FR hybrid vehicle in the first embodiment includes an engine Eng, a flywheel FW, a first clutch CL1, a motor generator MG, a second clutch CL2, and an automatic transmission AT. And a propeller shaft PS, a differential DF, a left drive shaft DSL, a right drive shaft DSR, a left rear wheel RL (drive wheel), and a right rear wheel RR (drive wheel). Note that FL is the left front wheel and FR is the right front wheel.

  The engine Eng is a lean-burnable engine such as a gasoline engine or a diesel engine. Based on an engine control command from the engine controller 1, the engine Eng uses an intake air amount by a throttle actuator, a fuel injection amount by an injector, and a spark plug. By controlling the ignition timing, the engine torque is controlled to coincide with the command value. The engine output shaft is provided with a flywheel FW.

  The first clutch CL1 is a dry clutch that is interposed between the engine Eng and the motor generator MG and engages / releases between the engine Eng and the motor generator MG. The first clutch CL1 is engaged including the half-clutch state (hydraulic OFF) by the first clutch control hydraulic pressure generated by the first clutch hydraulic unit 6 based on the first clutch control command from the first clutch controller 5.・ Opening (hydraulic ON) is controlled. If the first clutch CL1 is completely engaged, only the motor torque + engine torque is transmitted to the second clutch CL2.

  The motor generator MG is a synchronous motor generator in which a permanent magnet is embedded in a rotor and a stator coil is wound around a stator, and a three-phase AC generated by an inverter 3 is applied based on a control command from the motor controller 2. It is controlled by doing. The motor generator MG can operate as an electric motor that is driven to rotate by receiving power supplied from the battery 4 (hereinafter, this state is referred to as “powering”), and the rotor rotates energy from the engine Eng or the drive wheel. , The battery 4 can be charged by functioning as a generator that generates electromotive force at both ends of the stator coil (hereinafter, this operation state is referred to as “regeneration”). The rotor of the motor generator MG is connected to the transmission input shaft of the automatic transmission AT via a damper.

  The second clutch CL2 is interposed between the motor generator MG and the left and right rear wheels RL and RR, and generates transmission torque to the left and right rear wheels RL and RR, which are drive wheels, according to clutch hydraulic pressure (pressing force). A wet multi-plate brake or a wet multi-plate clutch. The second clutch CL2 is controlled to be engaged and disengaged including slip engagement and slip release by the control hydraulic pressure generated by the second clutch hydraulic unit 8 based on the second clutch control command from the AT controller 7. The first clutch hydraulic unit 6 and the second clutch hydraulic unit 8 are built in an AT hydraulic control valve unit CVU attached to the automatic transmission AT.

  The automatic transmission AT is, for example, a stepped transmission that automatically switches stepped gears such as forward 7 speed / reverse 1 speed according to the vehicle speed VSP, the accelerator opening APO, and the like. The second clutch CL2 is not newly added as a dedicated clutch, but is optimally arranged in the torque transmission path among a plurality of frictional engagement elements that are engaged at each gear stage of the automatic transmission AT. A clutch or brake is selected. Note that the output shaft of the automatic transmission AT is coupled to the left and right rear wheels RL and RR via a propeller shaft PS, a differential DF, a left drive shaft DSL, and a right drive shaft DSR.

  The FR hybrid vehicle of the first embodiment is referred to as an electric vehicle travel mode (hereinafter referred to as “EV mode”) and a hybrid vehicle travel mode (hereinafter referred to as “HEV mode”) according to the engagement / release state of the first clutch CL1. ) And two “running modes” and “engine start mode”. The “EV mode” is a mode in which the first clutch CL1 is released and the vehicle runs only with the power of the motor generator MG. The “HEV mode” is a mode in which the first clutch CL1 is engaged and the vehicle is driven by the power of the engine Eng and the motor generator MG. “Engine start mode” is the engine Eng that uses the power of the same motor generator MG while running in “EV mode” with only the power of the motor generator MG at the time of mode transition from “EV mode” to “HEV mode”. This is a mode for performing cranking.

Next, the control system of the hybrid vehicle will be described.
As shown in FIG. 1, the control system of the FR hybrid vehicle in the first embodiment includes an engine controller 1, a motor controller 2, an inverter 3, a battery 4, a first clutch controller 5, and a first clutch hydraulic unit 6. And an AT controller 7, a second clutch hydraulic unit 8, a brake controller 9, and an integrated controller 10. The engine controller 1, the motor controller 2, the first clutch controller 5, the AT controller 7, the brake controller 9, and the integrated controller 10 are connected via a CAN communication line 11 that can mutually exchange information. ing.

  The engine controller 1 inputs engine speed information from the engine speed sensor 12, a target engine torque command from the integrated controller 10, and other necessary information. Then, a command for controlling the engine operating point (Ne, Te) is output to the throttle valve actuator or the like of the engine Eng.

  The motor controller 2 inputs information from the resolver 13 that detects the rotor rotational position of the motor generator MG, the target MG torque command and target MG rotation speed command from the integrated controller 10, and other necessary information. Then, a command for controlling the motor operating point (Nm, Tm) of motor generator MG is output to inverter 3 (high voltage inverter). The battery 4 (high voltage battery) connected to the inverter 3 is monitored by a battery controller (not shown) for the battery charge SOC indicating the charge capacity of the battery 4. The information is used for control information of the motor generator MG and is supplied to the integrated controller 10 via the CAN communication line 11.

  The first clutch controller 5 inputs sensor information from the first clutch stroke sensor 15 that detects the stroke position of the piston 14a of the hydraulic actuator 14, a target CL1 torque command from the integrated controller 10, and other necessary information. . Then, a command for controlling engagement / disengagement of the first clutch CL1 is output to the first clutch hydraulic unit 6 in the AT hydraulic control valve unit CVU.

  The AT controller 7 includes an accelerator opening sensor 16 (accelerator opening detecting means), a vehicle speed sensor 17, and other sensors 18 (transmission input rotation speed sensor, inhibitor switch, second clutch output rotation speed sensor, etc.). Enter information from. Then, when driving with the D range selected, a control command for obtaining the searched gear position is searched for the optimum gear position based on the position where the operating point determined by the accelerator opening APO and the vehicle speed VSP exists on the shift map. Output to AT hydraulic control valve unit CVU. The shift map is a map in which an upshift line and a downshift line are written according to the accelerator opening and the vehicle speed. In addition to the above automatic shift control, when a target CL2 torque command is input from the integrated controller 10, a command for controlling the engagement / release of the second clutch CL2 is sent to the second clutch hydraulic unit 8 in the AT hydraulic control valve unit CVU. The second clutch control to output is performed.

  The brake controller 9 inputs a wheel speed sensor 19 for detecting the wheel speeds of the four wheels, sensor information from the brake switch sensor 20, a regenerative cooperative control command from the integrated controller 10, and other necessary information. And, for example, at the time of brake depression, if the regenerative braking force is insufficient with respect to the required braking force required from the brake stroke BS, the shortage is compensated with mechanical braking force (hydraulic braking force or motor braking force) Regenerative cooperative brake control is performed.

  The integrated controller 10 manages the energy consumption of the entire vehicle and has a function for running the vehicle with the highest efficiency. The motor rotation number sensor 21 for detecting the motor rotation number Nm and other sensors and switches 22 Necessary information and information via the CAN communication line 11 are input. The target engine torque command to the engine controller 1, the target MG torque command and the target MG speed command to the motor controller 2, the target CL1 torque command to the first clutch controller 5, the target CL2 torque command to the AT controller 7, and the brake controller 9 Regenerative cooperative control command is output.

  FIG. 2 is a flowchart showing an engine start control process executed by the integrated controller 10 of the FR hybrid vehicle to which the control device of the first embodiment is applied (engine start control means). Note that the processing content shown in FIG. 2 is executed with constant sampling. Hereinafter, each step will be described.

In step S1, the battery charge amount SOC, input RPM omega _Cl2i of the second clutch CL2, an output rotational speed omega _Cl2o of the second clutch CL2 receive, engine speed omega _e, the vehicle condition other controllers such vehicle speed VSP is measured Then, the process proceeds to step S2.

In step S2, the accelerator opening APO is measured from the accelerator opening sensor 16, the first clutch stroke x _Scl1 is _measured from the first clutch stroke sensor 15, and the brake SW signal Bsw is measured from the brake switch sensor 20, and the process proceeds to step S3. .

In step S3, the target drive torque Td ^* is calculated from the accelerator opening APO and the vehicle speed VSP, and the process proceeds to step S4.
Here, the target drive torque Td ^* is calculated based on, for example, a target drive torque calculation map using the accelerator opening APO and the vehicle speed VSP as parameters as shown in FIG.

In step S4, the target control mode CL1MODE (0: released, 1: slip, 2: engaged) of the first clutch CL1 and the second clutch CL2 are determined from the vehicle state such as the battery charge SOC, the target drive torque Td ^*, and the vehicle speed VSP. Target control mode CL2MODE (0: release, 1: slip, 2: engagement) is set, and the process proceeds to step S5.
Detailed calculation processing of the target control modes CL1MODE and CL2MODE of the respective clutches CL1 and CL2 is performed according to a flowchart described later shown in FIG.

In step S5, the engine torque command value Te ^* is calculated as follows based on the target control mode CL1MODE of the first clutch CL1 and the target drive torque Td ^*, and the process proceeds to step S6. The arithmetic expression is
1) When CL1MODE = 0 or CL1MODE = 1
Te ^* = 0 (1)
2) When CL1MODE = 2
Te ^* = Td ^* −T _{m_max} (2)
It becomes.
However,
T _{m_max} : Maximum output possible motor torque (negative value if SOC decreases)
It is.
Here, various calculation methods can be considered for the engine torque command value Te ^{* in} the case of CL1MODE = 2 (HEV mode). In this embodiment, the motor torque is utilized as much as possible to the target drive torque Td ^*. The shortage will be supplemented with engine torque.

In step S6, the first clutch torque capacity command value _Tcl1 ^* is calculated as follows, and the process proceeds to step S7. The arithmetic expression is
1) When CL1MODE = 0
T _cl1 ^* = 0 (3)
2) When CL1MODE = 1
T _cl1 ^* = T _crank (4)
3) When CL1MODE = 2
^{_{T cl1 * = T cl1_max (5}} )
It becomes.
However,
T _crank : cranking torque
T _{cl1_max} : The first clutch maximum torque capacity.

In step S7, it is determined whether or not the second clutch CL2 is in a slip state. Slip rotation number omega _Cl2slp of the second clutch CL2 - if the absolute value of the (second clutch input rotational speed omega _Cl2i second clutch output rotational speed _ω cl2o) becomes a predetermined value omega _{Cl2slp_th2} above steps it is determined that the slip state Proceed to S8, otherwise proceed to Step S12.

In step S8, following the determination that the second clutch CL2 is in the slip state in step S7, the basic second clutch torque capacity command value _{Tcl2_base} ^* is calculated as follows, and the process proceeds to step S9. The arithmetic expression is
1) When CL1MODE = 0 or CL1MODE = 1
T _{cl2_base} ^* = min (T _{d_evmax} , Td ^* ) (6)
2) When CL1MODE = 2
T _{cl2_base} ^* = Td ^* (7)
It becomes.
However,
min (A, B): Outputs the smaller value of A and B
T _{d_evmax} is the maximum drive torque during EV travel.

In step S9, the target control mode CL1MODE and second clutch output rotational speed measurement value omega _o of the first clutch CL1, from accelerator opening APO, and calculates a second clutch input rotational speed target value _ω cl2i ^*, the process proceeds to step S10 .
First, the second clutch slip rotation speed target value ω _{cl2_slp} ^* is calculated based on the following. Note that CL1MODE = 2 will be described for ease of explanation.
1) When CL1MODE = 2, the formula is
ω _{cl2_slp} ^* = f _{cl2_slp_cl1OP} (ω _o , APO) (8)
It becomes.
Here, f _{cl2_slp_cl1OP} (ω _o , APO) is a function having the second clutch output rotational speed measurement value ω _o and the accelerator opening APO as inputs. Actually, for example, it is set by an example of a map for calculating the target slip rotation speed in the “HEV mode” as shown in FIG. In this way, a desired lockup rotation speed (output rotation speed at which slip becomes 0) can be set according to the accelerator opening APO.
2) When CL1MODE = 0 or CL1MODE = 1, the formula is
ω _{cl2_slp} ^* = f _{cl2_slp_cl1OP} (ω _o , APO) + f _{cl2_Δωslp} (T _{eng_start} ) (9)
It becomes.
Here, f _{cl2_Δωslp} (T _{eng_start} ) is a function for calculating the amount of increase in slip rotation speed at the time of engine start, and engine start distribution motor torque T _{eng_start} (maximum output possible motor torque T _{m_max} and second clutch torque capacity command Value T _{cl2_base} ^* )). Actually, for example, when the engine start distribution motor torque T _{eng_start} decreases by using an example of a map for calculating the target slip rotation speed (increase) in the engine start mode as shown in FIG. 2. Increase the clutch slip rotation speed target value ω _{cl2_slp} ^* to a higher value (increase the increase amount). As a result, the disturbance from the first clutch CL1 cannot be completely canceled, and sudden engagement can be prevented even if the rotational speed decreases, and as a result, the engine Eng can be started without causing acceleration fluctuations.

Next, the basic input rotation speed target value ω _cl2i ^* is calculated from the slip rotation speed target value ω _{cl2_slp} ^* and the output rotation speed measurement value ω _{o according} to the following equation. The arithmetic expression is
ω _cl2i ^* = ω _{cl2_slp} ^* + ω _o (10)
It becomes.
Finally subjected to upper and lower limits to the second clutch input rotational speed target value omega _Cl2i calculated from the above equation ^*, the final second clutch input rotational speed target value _ω cl2i ^*. The upper and lower limit values are the upper and lower limit values of the engine speed.

In step S10, the motor torque command value Tm ^* for slip control is calculated so that the second clutch input rotational speed target value ω _cl2i ^* and the second clutch input rotational speed measured value ω _cl2i match, and the process proceeds to step S11.
There are various calculation (control) methods. For example, calculation is performed based on the following expression using PI control. The actual calculation is calculated using a recurrence formula obtained by discretization by Tustin approximation or the like. The arithmetic expression is
Tm ^* = {(K _Pm · s + K _Im ) / s)} · (ω _cl2i ^* −ω _cl2i ) (11)
It becomes.
However,
K _Pm : Proportional gain for motor control
K _Im : Motor control integral gain s: Differential operator.

In step S11, the basic second clutch torque capacity command value _T cl2_base ^* and a slip control of the motor torque command value Tm ^*, the engine torque command value T _e ^*, the first clutch torque capacity command value T _cl1 ^*, first clutch CL1 target control mode CL1MODE, he calculates a second clutch torque capacity command value T _cl2 ^* for slip control and the like, the process proceeds to step S18. Hereinafter, description will be made with reference to the block diagram of the rotation speed control system of the second clutch CL2 shown in FIG.

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.
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 torque capacity command value T _{cl2_FF} of the second clutch CL2 is calculated. To do. The actual calculation is calculated using a recurrence formula obtained by discretization by Tustin approximation or the like. The arithmetic expression is
(T _{cl2_FF} ) / (T _{cl2_base} ^* ) = G _FF (s) = (τ _cl2 · s + 1) / (τ _{cl2_ref} · s + 1) (12)
It becomes.
However,
tau _cl2: when the second clutch model constants _τ cl2_ref: a second clutch control nominal response time constant.

Next, according to the target control mode CL1MODE of the first clutch CL1, and calculates a second clutch torque capacity target value T _{Cl2_t} as follows. Since it is unlikely that CL1MODE = 0 in this calculation unit (when CL2MODE = 1) from step S4, the case where CL1MODE = 0 is omitted. The arithmetic expression is
1) When CL1MODE = 1
^{_{T cl2_t = T cl1 * + T}} cl2_base * (13)
2) When CL1MODE = 2
T _{cl2_t} = T _{cl2_base} ^* −Te ^* (14)
It becomes.
Here, as a supplementary explanation, the second clutch torque capacity target value _{Tcl2_t} represents the torque that the motor torque during slip control is output in an ideal state. In the steady state, the F / B compensator _compares the torque capacity of the second clutch CL2 so that the second clutch torque capacity target value _{Tcl2_t matches} the motor torque command value during slip control (almost the same value as the actual motor torque). Correct.

Next, the second clutch torque capacity reference value T _{cl2_ref} is calculated based on the second clutch _reference model G _{cl2_REF} (s) shown in the following equation. The arithmetic expression is
(T _{cl2_ref} ) / (T _{cl2_t} ) = G _{cl2_REF} (s) = 1 / (τ _{cl2_ref} · s + 1) (15)
It becomes.

Next, the F / B torque capacity command value T _{cl2_FB} of the second clutch CL2 is calculated from the second clutch torque capacity reference value T _{cl2_ref} and the motor torque command value Tm ^* for rotational speed control described above based on the following equation. The arithmetic expression is
T _{cl2_FB} = {(K _Pcl2 s + K _Iccl2 ) / s} x (T _{cl2_ref} −Tm ^* ) (16)
It becomes.
However,
K _Pcl2 : Proportional gain for second clutch control
K _Iccl2 : Second 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. The arithmetic expression is
_{T cl2_FB = {(K Pcl2 s} + K Iccl2) / s} × (T cl2_ref -Tm * -T Icl2_est) (17)
It becomes.
Here, T _{Icl2_est} is an inertia torque estimated value, and is obtained, for example, by multiplying the input rotational speed change amount (differential value) by the moment of inertia around the input shaft.
Then, the F / F torque capacity command value T _{cl2_FF of} the second clutch CL2 and the F / B torque capacity command value T _{cl2_FB} are added to calculate a second clutch capacity command value T _cl2 ^* for final slip control.

In step S12, following the determination that the slip detection of the second clutch CL2 is not performed in step S7, the above-described motor torque command value Tm ^* for slip control and the second clutch torque capacity command value _Tcl2 ^* are calculated. Internal state variables are initialized (the integral term is reset so that the command value switches smoothly), and the process proceeds to step S13.

  In step S13, it is determined whether or not the target control mode of the second clutch CL2 is CL2MODE = 2 (engagement mode). If CL2MODE = 2, the process proceeds to step S14, otherwise the process proceeds to step S16.

In step S14, following the determination that the second clutch CL2 is in the engagement mode in step S13, the second clutch torque capacity command value _Tcl2 ^* for engagement control is calculated as follows, and the process proceeds to step S15. The arithmetic expression is
1) When T _{cl2_z1} ^* <T _{cl2_max}
T _cl2 ^* = T _{cl2_z1} ^* + ΔT _{cl2_LU} (18)
2) When T _{cl2_z1} ^* ≧ T _{cl2_max}
T _cl2 ^* = T _{cl2_max} (19)
It becomes.
However,
_T cl2_max: second clutch maximum torque capacity _ΔT cl2_LU: torque capacity change rate at the time the slip → engagement Migration
T _{cl2_z1} ^* : Second torque capacity command value previous value.

In step S15, based on the first clutch control mode CL1MODE and the target drive torque Td ^* , a motor torque command value Tm ^* for engagement control is calculated as follows, and the process proceeds to step S18.
Since it is unlikely that CL1MODE = 1 in this operation unit (when CL2MODE = 2) from step S4, the case where CL1MODE = 1 is omitted. The arithmetic expression is
1) When CL1MODE = 0
Tm ^* = Td ^* (20)
2) When CL1MODE = 2
^{Tm * = Td * -Te * (} 21)
It becomes.

In step S16, following the determination that the second clutch CL2 is not in the engagement mode in step S13, the second clutch torque capacity command value T _cl2 ^* for slip transition control is calculated as follows, and the process proceeds to step S17.
1) When CL1MODE = 0 or CL1MODE = 1
i) T _{cl2_z1} ^* ≧ T _{m_z1} ^*
The arithmetic expression is
T _cl2 ^* = f (APO) (22)
It becomes.
The equation (22), when the second torque capacity command value previous value _T cl2_z1 ^* is the motor torque command value previous value _T m_z1 ^* above, the second clutch torque capacity command value ^{_{T cl2 *, T cl2 * =}} ( In the range of T _{m_ev} ^{* to} T _{d_evmax} ), the equation is set such that the smaller the accelerator opening APO is, the smaller the value is calculated (fifth operation).

ii) T _{cl2_z1} ^* <T _{m_z1} ^*
The arithmetic expression is
T _cl2 ^* = T _{cl2_z1} ^* −ΔT _cl2slp (23)
It becomes.
This equation (23) shows that when the second clutch CL2 does not slip even if the motor torque command value previous value T _{m_z1} ^* exceeds the second torque capacity command value previous value T _{cl2_z1} ^* , the torque capacity command to the second clutch CL2 The value indicates that the second clutch torque capacity command value _Tcl2 ^* , which is a value, is decreased at a gentler gradient than the increase gradient of the motor torque command value Tm ^* to the motor generator MG (sixth operation).
Further, when the switching condition was T _{D_evmax} instead of _T cl2_z1 ^*, this formula (23), the motor torque command value previous value _T m_z1 ^* is the second even exceed the maximum driving torque T _{D_evmax} during EV traveling When the clutch CL2 does not slip, the second clutch torque capacity command value _Tcl2 ^* , which is the torque capacity command value for the second clutch CL2, is set to a gentler slope than the increasing slope of the motor torque command value Tm ^* to the motor generator MG. (7th operation).
2) When CL1MODE = 2, the formula is
i) When CL2MODE = 0
T _cl2 ^* = 0 (24)
ii) When CL2MODE = 1
T _cl2 ^* = T _{cl2_z1} ^* −ΔT _{cl2_slp} (25)
It becomes.
However,
T _{m_ev} ^* : EV motor torque command value immediately before mode switching
T _{m_z1} ^* : Previous value of motor torque command value
T _{cl2_z1} ^* : Second clutch torque capacity command value previous value ΔT _{cl2_slp} : Torque capacity change rate at the time of engagement → slip transition.

In step S17, the motor torque command value Tm ^* for slip transition control is calculated as follows, and the process proceeds to step S18. Since it is unlikely that CL1MODE = 0 in this operation unit (when CL2MODE = 0 or CL2MODE = 1) from step S4, the case where CL1MODE = 0 is omitted.
1) When CL1MODE = 1 In order to determine whether the torque capacity of the second clutch CL2 has become constant, the second clutch torque capacity estimation model G _{cl2_est} (s) is _{added to} the second clutch torque capacity command value T _cl2 ^* . alms, calculates a second clutch torque capacity estimation value _T cl2_est. The arithmetic expression is
(T _{cl2_est} ) / (T _cl2 ^* ) = G _{cl2_est} (s) = 1 / (τ _{cl2_ref} · s + 1) (26)
It becomes.
Hereinafter, if the absolute value of the deviation between the second clutch torque capacity command value T _cl2 ^* for slip transition control and the second clutch torque capacity estimated value T _{cl2_est} is less than or equal to a predetermined value, the difference is not constant. Judge.

i) If the torque capacity of the second clutch CL2 is not constant:
Tm ^* = T _cl2 ^* (27)
It becomes.
When the torque capacity of the second clutch CL2 is not constant after switching from the “EV mode” to the “engine start mode”, the equation (27) is obtained by calculating the motor torque command value Tm ^* to the motor generator MG as the second clutch. This represents a stepwise increase to the second clutch torque capacity command value _Tcl2 ^* to CL2 (third operation).
ii) When the torque capacity of the second clutch CL2 is constant:
Tm ^* = T _{m_z1} ^* + ΔT _{m_slp} (28)
It becomes.
This equation (28) is obtained by _setting the second clutch torque capacity command value _Tcl2 ^* to a constant value equal to or greater than the EV drive torque phase immediately before the mode change, after switching from the “EV mode” to the “engine start mode”. 2 is gradually increased motor torque command value Tm ^* to the motor-generator MG to detect a slip of the clutch CL2, it represents possible to slip by the motor torque (the first operation). Alternatively, after the torque capacity of the second clutch CL2 becomes substantially constant, the motor torque command value Tm ^* to the motor generator MG is gradually increased to delay the increase timing by the hydraulic response delay (second operation) ).
However,
ΔT _{m_slp} : Torque capacity change rate at the time of fastening → slip transition. The torque capacity change rate ΔT _{m_slp} at the time of transition from the engagement to the slip is set so that the amount of increase (increase rate) per unit time of the motor torque command value Tm ^* to the motor generator MG increases as the accelerator opening APO increases. (Fourth operation).
2) When CL1MODE = 2, the formula is
Tm ^* = Td ^* −Te ^* (29)
It becomes.

In step S18, a current command value I _cl2 ^* to the solenoid valve for controlling the hydraulic pressure applied to the second clutch CL2 is _calculated from the second clutch torque capacity command value T _cl2 ^*, and the process proceeds to step S19.
Actually, the calculation is performed using the second clutch torque capacity-hydraulic pressure conversion map shown in FIG. 7 and the second clutch torque hydraulic 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 current command value I _cl1 ^* to the solenoid valve for controlling the hydraulic pressure applied to the first clutch CL1 is calculated from the first clutch torque capacity command value T _cl1 ^*, and the process proceeds to step S20.
Note that the process of calculating the current command value I _cl1 ^* from the first clutch torque capacity command value T _cl1 ^* is performed according to a later-described flowchart shown in FIG.

In step S20, the calculated engine torque command value Te ^* is transmitted to the engine controller 1, the calculated motor torque command value Tm ^* is transmitted to the motor controller 2, and the calculated first clutch current command value I _cl1 ^*. _Is transmitted to the first clutch controller 5, the calculated second clutch current command value I _cl2 ^* is transmitted to the AT controller 7, and the process proceeds to the end.

  FIG. 9 is a flowchart showing target control mode calculation processing (step S4 in FIG. 2) of each clutch executed by the integrated controller 10 of the FR hybrid vehicle to which the control device of the first embodiment is applied. Hereinafter, each step will be described.

In step S401, it is determined whether it is necessary to start engine Eng (or prohibit engine stop) from battery charge SOC and target drive torque Td ^* . EV driving is difficult when the battery charge SOC is equal to or less than the predetermined value SOCth1, or the target driving torque Td ^* is the maximum driving torque T _{d_evmax} (maximum motor torque T _{m_max} and cranking torque T during EV driving) _If the difference is equal to or greater than the _crank difference), it is difficult to run the EV. Therefore, it is determined that the engine Eng needs to be started, and the process proceeds to step S403. Otherwise, the process proceeds to step S402.

  In step S402, following the determination that there is no engine start request in step S401, the engine start completion flag fENGFINISH and the cranking start permission flag fCRANKOK are each reset to 0, and the process proceeds to step S409.

In step S403, following the determination that there is an engine start request in step S401, the engine start completion flag fENGFINISH is set as follows. The first clutch stroke x _scl1 is less than or equal to a predetermined value x _{scl1_th1} (the first clutch stroke x _scl1 has a smaller clutch torque capacity as the value is smaller. See FIG. 10 as an example of characteristics), and the first clutch If the absolute value of the slip rotational speed ω _{cl1slp of} CL1 (second clutch input rotational speed ω _{cl2i −engine} rotational speed ω _e ) is less than the predetermined value ω _{cl1slp_th1} , set fENGFINISH to 1 (engine start complete), otherwise Set to 0 (engine start incomplete).

  In step S404, it is determined based on the engine start completion flag fENGFINISH described above whether engine start is completed. If fENGFINISH is 1, it is determined that the engine has been started, and the process proceeds to step S407. Otherwise, the process proceeds to step S405.

In step S405, the cranking start permission flag fCRANKOK is set as follows. When the slip rotational speed ω _cl2slp (second clutch input rotational speed ω _{cl2i −second} clutch output rotational speed ω _cl2o ) of the second clutch CL2 exceeds the predetermined value ω _{cl2slp_th1, fCRANKOK} is set to 1 (cranking start permission) Otherwise, set to 0 (no cranking start allowed).

  In step S406, based on the cranking start permission flag fCRANKOK described above, it is determined whether or not cranking start is permitted. If fCRANKOK is 1, it is determined that cranking start is permitted, and the process proceeds to step S411. Otherwise, the process proceeds to step S410.

  In step S407, it is determined whether or not the lockup of the second clutch CL2 is permitted. If the vehicle speed VSP is greater than or equal to the predetermined value VSP_th1, the lockup permission is determined and the process proceeds to step S414, and otherwise the process proceeds to step S408.

  In step S408, it is determined from the brake SW signal Bsw whether the brake is being applied. If Bsw is 1 (brake ON), the process proceeds to step S413. Otherwise, the process proceeds to step S412.

  In step S409, CL1MODE is set to 0 (released) and CL2MODE is set to 2 (engaged) (EV mode) following the flag reset in step S402 based on the determination that there is no engine start request.

  In step S410, following the determination that engine start has not been completed and cranking start is not permitted, CL1MODE is set to 0 (release) and CL2MODE is set to 1 (slip) (in engine start mode). Before cranking).

  In step S411, following the determination that engine start has not been completed and that cranking start is permitted, CL1MODE is set to 1 (slip), and CL2MODE is set to 1 (slip). Ranking)

  In step S412, the engine start is complete, but lock-up is not permitted and it is determined that the brake is not being applied. Then, CL1MODE is set to 2 (engaged) and CL2MODE is set to 1 (slip) (engine start) WSC drive mode after completion).

  In step S413, the engine start is completed, but lockup is not permitted, and after determining that braking is in progress, CL1MODE is set to 2 (engaged) and CL2MODE is set to 0 (released) (engine) Neutral deceleration mode after start-up).

  In step S414, CL1MODE is set to 2 (engaged) and CL2MODE is set to 2 (engaged), respectively, following the determination that engine start is complete and lock-up is permitted (HEV mode).

  FIG. 11 is a flowchart showing a first clutch current command value calculation process (step S19 in FIG. 2) executed by the integrated controller 10 of the FR hybrid vehicle to which the control device of the first embodiment is applied. Hereinafter, each step will be described.

In step S191, the first clutch torque capacity command value T _cl1 ^*, previously acquired first clutch torque capacity - using the map created (FIG. 10) by the stroke characteristic, calculates a first clutch stroke command value x _SCL1 ^* To do.

In step S192, from the first clutch stroke command value x _SCL1 ^* and the stroke measurement value is calculated based on the following a hydraulic pressure command value P _cl1 ^*. In the first embodiment, a two-degree-of-freedom control method is adopted as in step S11 of FIG. 2 (FIG. 12).

First, from the first clutch stroke command value x _scl1 ^* , an F / F using a phase compensation filter consisting of the inverse system of the reference response transmission characteristic as shown in the following equation and the control target transmission characteristic after hydraulic pressure correction described later is used. _Calculate hydraulic pressure command value _{Pcl1_FF} . The arithmetic expression is
(P _{cl1_FF} ) / (x _scl1 ^* ) = G _{cl1_FF} (s) = {(Ms ² + Cs + K _{cl1_ref} ) ω ² _{cl1_ref} } / {s ² + 2ζ _{cl1_ref} ω _{cl1_ref} s + ω ² _{cl1_ref} } (30)
It becomes.
However,
C: First clutch mechanism viscosity coefficient
K _{cl1_ref} : spring constant to be controlled after hydraulic pressure correction ζ _{cl1_ref} : first clutch reference response damping coefficient ω _{cl1_ref} : first clutch reference response natural frequency
M: clutch mass.
Next, the stroke reference value x _{scl1_ref} is calculated from the first clutch stroke command value x _scl1 ^* using a filter representing the reference response transmission characteristic as shown in the following equation. The arithmetic expression is
(x _{scl1_ref} ) / (x _scl1 ^* ) = G _{cl1_ref} (s) = (ω ² _{cl1_ref} ) / (s ² + 2ζ _{cl1_ref} ω _{cl1_ref} s + ω ² _{cl1_ref} ) (31)
It becomes.

Then, from the deviation x _{Scl1_err} stroke reference value x _{Scl1_ref} and the stroke measured value x _SCL1, it calculates the F / B pressure command value P _{Cl1_FB} based on the following equation. The arithmetic expression is
(P _{cl1_FB} ) / (x _{scl1_err} ) = G _{cl1_FB} (s) = (K _{Pgain_cl1} s + K _{Igain_cl1} + K _{Dgain_cl1} s ² ) / s (32)
It becomes.
However,
K _{Pgain_cl1} : Proportional gain
K _{Igain_cl1:} integral gain
K _{Dgain_cl1} : Differential gain. Finally, by adding the F / F hydraulic pressure command value P _{Cl1_FF} and F / B pressure command value P _{Cl1_FB,} and oil pressure command value P _cl1 ^*.

In step S193, the hydraulic pressure command value is corrected so that the slope of the reaction force (hydraulic pressure) -stroke characteristic of the clutch mechanism (the spring characteristic of the diaphragm spring) becomes a characteristic desired by the designer. Hereinafter, a detailed method will be described.
From the difference between the first clutch hydraulic pressure estimated value P _{cl1_est} calculated using the map created based on the characteristics shown in FIG. 10 and the reaction force reference value P _{cl1_ref} calculated using the reference spring characteristics from the stroke measurement value, the hydraulic pressure correction is performed. Calculate the value P _{cl1_hosei} . The arithmetic expression is
P _{cl1_hosei} = P _{cl1_ref} −P _{cl1_est} = K _ref · x _scl1 −f _xscl1-p (x _scl1 ) (33)
It becomes.
However,
_{f xscl1-p (x scl1)} : Hydraulic - is a function showing a stroke characteristic.
From the hydraulic correction value P _{Cl1_hosei} and the hydraulic command value P _cl1 ^* calculated above, to calculate the final hydraulic pressure command value P _{Cl1_com} based on the following equation. The arithmetic expression is
^{_{P cl1_com = P cl1 * -P cl1_hosei}} (34)
It becomes.

In step S194, the current command value I _cl1 ^* is calculated from the final hydraulic pressure command value P _{cl1_com} using a map (see FIG. 8) created based on previously acquired characteristics, as with the second clutch CL2.

Next, the operation will be described.
First, the “problem of the engine start control comparative example” will be described, and then the actions in the control apparatus for the FR hybrid vehicle of the first embodiment will be described as “engine start control action by the first action” to “engine by the seventh action”. The description will be divided into “starting control action”.

[Problems of engine start control comparison example]
FIG. 13 is a time chart showing characteristics of the accelerator opening, the motor rotation speed, the second clutch output rotation speed, the engine rotation speed, the second clutch torque capacity, the motor torque, and the motor control state in the engine start control comparative example. . FIG. 14 is a time chart showing characteristics of the accelerator opening, the second clutch torque capacity, the motor torque, the rotational speed, the slip rotational speed, and the acceleration that represent problems in the engine start control comparative example.

  “EV mode” using only the power of the motor generator in a hybrid vehicle having a drive system in which an engine, a first clutch for starting the engine, a motor, and a transmission having a second clutch capable of driving force control are arranged in order. An engine start control comparison example in which the engine is started in order to shift to the “HEV mode” when the driver depresses the accelerator pedal during traveling in FIG. 13 will be described.

From the engine start request (time t1) to the slip detection of the second clutch (time t2), the torque capacity command value for the second clutch, which is the start clutch, is set from the maximum value to the EV immediately before the engine start request. If the second clutch is not slipped, it is further lowered until it slips until the driving torque phase equivalent value is reached.
From slip detection (time t2) of the second clutch to complete explosion (time t3), the motor control is switched from torque control to rotation speed control, the slip rotation speed of the second clutch is increased, and the slip rotation speed is sufficiently large. Then, the first clutch is semi-engaged and cranked. When the slip rotation speed becomes sufficiently large, the torque capacity of the second clutch is maintained.
From the complete engine explosion (time t3) to the completion of engine start control (time t4), the first clutch is completely engaged, and the engine speed is increased to the self-sustaining rotation range.
In the engine start control of this comparative example, the second clutch torque capacity is kept low during the period from the engine start request (time t1) to the completion of the engine start control (time t4), so that the shock associated with the engine start is caused by the second clutch. It shuts off and realizes a smooth engine start.

  Thus, in the engine start method for the hybrid vehicle in the comparative example, the control for slipping the second clutch prior to the cranking is performed depending on the torque capacity control of the second clutch. However, the hydraulic clutch has a hydraulic response delay, and the hydraulic response delay of the clutch torque capacity (hydraulic pressure) increases with respect to the clutch torque command (the solid line characteristic of the measured value in FIG. 14).

  Therefore, when the clutch hydraulic response delay is substantially ignored, the case 1 (dotted line characteristic in FIG. 14) is used, and when the clutch hydraulic response delay is large, the case 2 (solid line characteristic in FIG. 14) is used. As is apparent from the comparison between the dotted line characteristic and the solid line characteristic of the rotational speed, in the case 2 where the hydraulic response delay of the second clutch is large, the rise of the slip rotational speed is delayed and the case 2 Slip detection timing is delayed. As a result, engine start by cranking performed by detecting that the second clutch is in the slip state is delayed.

  In addition, if the timing for detecting the slip state of the second clutch is delayed, the torque capacity command value that is gradually decreased until the slip state is detected is excessively reduced. For this reason, as indicated by the solid line characteristic of acceleration in FIG. 14, the vehicle acceleration immediately before the engine start request cannot be maintained, and G is lost.

[Engine start control action by first operation]
FIG. 15 shows the accelerator opening, the motor speed, the second clutch output speed, the engine speed, the second clutch torque capacity, the motor torque, and the motor control in the engine start control in the FR hybrid vehicle control apparatus of the first embodiment. It is a time chart which shows each characteristic of a state. FIG. 16 is an A part enlarged time chart of FIG. 15 showing characteristics of the second clutch torque capacity / motor torque from the engine start request (time t1) to the slip detection (time t2) due to the first operation. FIG. 17 is a time chart showing characteristics of accelerator opening, second clutch torque capacity, motor torque, rotation speed, slip rotation speed, and acceleration in engine start control of the FR hybrid vehicle of the first embodiment. Hereinafter, the engine start control action by the first operation will be described with reference to FIGS.

While traveling in the “EV mode”, in the flowchart of FIG. 2, step S1 → step S2 → step S3 → step S4 → step S5 → step S6 → step S7 → step S12 → step S13 → step S14 → step S15 → The flow from step S18 to step S19 to step S20 is repeated.
That is, before the engine start request (time t1), the second clutch torque capacity command value T _cl2 ^* for engagement control is calculated in step S14, and in step S15, the first clutch control mode CL1MODE and the target drive torque Td are calculated. Based on ^* , the motor torque command value Tm ^* for fastening control is calculated.

While driving in this "EV mode", the driver depresses the accelerator pedal, and CL1MODE is 0 (released) and CL2MODE is 1 (slip) according to the calculation process of the target control mode of each clutch CL1, CL2 (Fig. 9). 2), the flow from step S1 to step S13 to step S16 → step S17 → step S18 → step S19 → step S20 is repeated in the flowchart of FIG.
That is, from the engine start request (time t1) to the slip detection (time t2), in step S16, the second clutch torque capacity command value T _cl2 for slip transition control with a constant value equal to or greater than the EV drive torque phase immediately before the mode change or the like. ^* Is calculated, and in step S17, a motor torque command value Tm ^* for slip transition control that is gradually increased until a slip of the second clutch CL2 is detected is calculated.

When the slip of the second clutch CL2 is detected, the process proceeds from step S1 to step S7 to step S8 → step S9 → step S10 → step S11 → step S18 → step S19 → step S20 in the flowchart of FIG. The flow is repeated.
That is, when slip is detected (time t2), the first clutch torque capacity command value T _cl1 ^* based on the cranking torque T _crank is calculated in step S6, and the second clutch input rotation speed target value ω _cl2i is calculated in step S10. The motor torque command value Tm ^* for slip control is calculated so that ^* and the second clutch input rotational speed measurement value ω _cl2i match, and in step S11, the basic second clutch torque capacity command value T _{cl2_base} ^* and slip control the motor torque command value Tm ^*, the engine torque command value T _e ^*, the first clutch torque capacity command value T _cl1 ^*, the target control mode CL1MODE, the second clutch torque capacity command value for the slip control and the like of the first clutch CL1 T _cl2 ^* is calculated.

  While driving in the “EV mode” using only the power of the motor generator MG in the FR hybrid vehicle of the first embodiment, when the driver depresses the accelerator pedal, the engine Eng is started to shift to the “HEV mode”. One operation of the engine start control action will be described with reference to FIGS. 15 and 16.

The engine start request (time t1) until the slip detection of the second clutch CL2 (time t2), the second second clutch torque capacity command value for the clutch CL2 T _cl2 ^* at the same time starting clutch and engine start request, the maximum The value is immediately reduced to the EV drive torque equivalent value immediately before the engine start request, and then the second clutch torque capacity command value _Tcl2 ^* is kept constant. On the other hand, the motor torque command value Tm ^* for the motor generator MG is gradually increased until the second clutch CL2 enters the slip state from the same timing as the engine start request.
From the slip detection (time t2) of the second clutch CL2 to the complete engine explosion (time t3), the motor control is switched from torque control to rotation speed control, the slip rotation speed of the second clutch CL2 is increased, and the slip rotation speed is increased. After becoming sufficiently large, the first clutch CL1 is semi-engaged and cranked.
From the engine explosion (time t3) to the engine start control completion (time t4), the first clutch CL1 is completely engaged, and the engine speed is increased to match the motor speed.

In this first operation, in the engine start control, the second clutch torque capacity command value T _cl2 ^* is kept low between the engine start request (time t1) and the engine start control completion (time t4). Similarly, the shock associated with engine start is shut off by the second clutch CL2, thereby realizing a smooth engine start.

Further, as shown in the second clutch torque capacity characteristic of FIG. 17, while the second clutch torque capacity command value _Tcl2 ^* is kept constant by the EV drive torque phase equal value, the motor torque command value Tm ^* is changed by the second clutch CL2. Gradually increase until slipping occurs. As described above, the control for slipping the second clutch CL2 prior to the cranking is performed by the motor torque with no hydraulic response delay. For this reason, as shown in the slip rotation speed characteristic of FIG. 17, the time from the engine start request until the slip state of the second clutch CL2 is detected is compared with the case 2 of the comparative example in which the hydraulic response delay of the clutch is large. , About 30% time savings. Along with this, the engine start time is also shortened by about 20% compared to the case 2 of the comparative example in which the hydraulic pressure response delay of the clutch is large.

Moreover, not only is the timing for detecting the slip state of the second clutch CL2 early, but the second clutch torque capacity command value _Tcl2 ^* is kept constant until the slip state is detected. For this reason, as shown by the solid line characteristics of acceleration in FIG. 17, the vehicle acceleration immediately before the engine start request is secured, and G loss is prevented 100%.

  As described above, in the engine start control by the first operation, after switching from the “EV mode” to the “engine start mode”, the second clutch torque capacity command value is a value equal to or greater than the EV drive torque phase etc. immediately before the mode change. The motor torque command value is gradually increased until slip is detected, in other words, the second clutch CL2 is slipped by the motor torque.

  In this way, the slip is detected by the motor start request (time t1) as compared with the comparative example because the slip is caused by the motor torque having a quick response (can be regarded as almost no delay compared to the hydraulic second clutch CL2). The time required until (time t2) can be shortened, and the engine start can be accelerated accordingly. In addition, since the torque capacity command value is not lowered more than necessary, it is possible to ensure the acceleration equal to or higher than that immediately before the engine start request, and to prevent G loss.

[Engine start control action by second operation]
FIG. 18 is an A part enlarged time chart of FIG. 15 showing characteristics of the second clutch torque capacity / motor torque from the engine start request (time t1) to the slip detection (time t2) due to the second operation. Hereinafter, the engine start control action by the second operation will be described with reference to FIG.

  As shown in FIG. 18, in the second operation, the actual capacity of the second clutch torque decreases due to the hydraulic response delay from the second clutch torque capacity command value, and the second clutch torque capacity command value and the second clutch torque capacity match. The motor torque command value is gradually increased from the timing at which the second clutch torque capacity becomes substantially constant. In other words, it differs from the first operation (FIG. 16) in that the timing for gradually increasing the motor torque command value is delayed by the hydraulic response delay.

  Therefore, in the engine start control by the second operation, after the “EV mode” is switched to the “engine start mode”, the second clutch torque capacity command value is made constant at a value equal to or higher than the EV drive torque phase immediately before the mode change. The motor torque command value is gradually increased until the slip is detected after the actual value of the second clutch torque capacity becomes constant.

  By this second operation, the motor torque is gradually increased after confirming that the actual second clutch torque capacity is in a stable state. For this reason, it is suppressed that the second clutch torque capacity fluctuates after transition to the slip state, and the vehicle acceleration is prevented from decreasing between the slip detection and the completion of the engine start control.

[Engine start control action by third action]
FIG. 19 is an A part enlarged time chart of FIG. 15 showing characteristics of the second clutch torque capacity / motor torque from the engine start request (time t1) to the slip detection (time t2) according to the third operation. Hereinafter, the engine start control action by the third operation will be described with reference to FIG.

  When the third operation is switched from the “EV mode” to the “engine start mode” and an engine start request (time t1) is issued, as shown in FIG. 19, the motor torque command value is set to the torque to the second clutch CL2. The operation is to increase stepwise up to a predetermined value below the capacity command value. That is, this is different from the second operation (FIG. 18) in which the motor torque command value in the “EV mode” is maintained as it is from the engine start request (time t1) to the timing when the second clutch torque capacity becomes substantially constant.

  Therefore, in the engine start control by the third operation, after switching from the “EV mode” to the “engine start mode”, the second clutch torque capacity command value is made constant at a value equal to or higher than the EV drive torque phase immediately before the mode change. When the engine start request (time t1) is issued, the motor torque command value is kept constant at a value stepwise increased to a predetermined value equal to or less than the second clutch torque capacity command value, and the second clutch torque capacity The motor torque command value is gradually increased until the slip is detected after the actual value becomes constant.

  By this third operation, the motor torque command value can be quickly brought close to the second clutch torque capacity command value from the timing of the engine start request. For this reason, it becomes easier for the second clutch CL2 to start the slip, and the time until the slip detection is further shortened compared to the operation 2.

[Engine start control action by fourth operation]
FIG. 20 is an A part enlarged time chart of FIG. 15 showing characteristics of the second clutch torque capacity / motor torque from the engine start request (time t1) to the slip detection (time t2) according to the fourth operation. Hereinafter, the engine start control action by the fourth operation will be described with reference to FIG.

  When the fourth operation is switched from the “EV mode” to the “engine start mode” and an engine start request (time t1) is issued, the motor torque command value is increased as the accelerator opening APO increases as shown in FIG. This is an operation for increasing the increase amount (increase rate) per unit time of the motor torque command value. As in the second and third operations, the acceleration torque of the motor torque command value that gradually increases to make the second clutch CL2 slip after the CL2 torque becomes substantially constant is similarly applied to the accelerator. The increase rate of the motor torque command value may be increased as the opening degree APO is increased. That is, it differs from the first operation in which the increasing gradient is not particularly defined in that the increasing gradient of the motor torque command value that is gradually increased to bring the second clutch CL2 into the slip state is defined by the accelerator opening APO.

  Therefore, in the engine start control by the fourth operation, after switching from the “EV mode” to the “engine start mode”, the second clutch torque capacity command value is kept constant at a value equal to or greater than the EV drive torque phase immediately before the mode change. When the engine start request (time t1) is issued, the motor torque command value is gradually increased by increasing the increase amount (increase rate) per unit time as the accelerator opening APO is larger.

  By this fourth operation, the increasing gradient of the motor torque command value is determined by the accelerator opening APO representing the driver's intention to increase the driving force or the acceleration intention. For this reason, for example, if the accelerator opening APO is large and the driver wants to start the engine immediately, the motor torque will be increased quickly and slipped quickly, and the early timing will depend on the driver's intention to increase driving force and acceleration. Thus, the engine start is achieved.

[Engine start control action by fifth operation]
FIG. 21 is an A part enlarged time chart of FIG. 15 showing characteristics of the second clutch torque capacity / motor torque from the engine start request (time t1) to the slip detection (time t2) according to the fifth operation. Hereinafter, the engine start control action by the fifth operation will be described with reference to FIG.

  As shown in FIG. 21, in the fifth operation, when an engine start request (time t1) is issued, the torque capacity command value for the second clutch CL2 is decreased as the accelerator opening APO is increased. is there. However, the torque capacity command value for the second clutch CL2 has a lower limit value that is equal to or greater than the EV drive torque phase immediately before mode switching. That is, when an engine start request (time t1) is issued, the second operation is different from the first operation to the fourth operation in which the second clutch torque capacity command value is made constant at a value equal to or higher than the EV drive torque phase immediately before mode switching.

  Therefore, in the engine start control by the fifth operation, when the engine start request (time t1) is issued after switching from the “EV mode” to the “engine start mode”, the second clutch torque capacity command value becomes the accelerator opening degree. The larger the APO, the smaller the value.

  By this fifth operation, the second clutch torque capacity command value is determined by the accelerator opening APO representing the driver's intention to increase the driving force or the acceleration intention. For this reason, for example, when the accelerator opening APO is large and the driver wants to start the engine immediately, the second clutch torque capacity command value is decreased, the second clutch torque capacity is decreased, and the driver quickly slips. The engine is started at an early timing according to the intention of increasing the driving force and the intention of acceleration.

[Engine start control action by sixth operation]
FIG. 22 is an A part enlarged time chart of FIG. 15 showing characteristics of the second clutch torque capacity / motor torque from the engine start request (time t1) to the slip detection (time t2) according to the sixth operation. Hereinafter, the engine start control action by the sixth operation will be described with reference to FIG.

  In the sixth operation, as shown in FIG. 22, if the second clutch CL2 does not slip even if the motor torque command value is equal to or greater than the second clutch torque capacity command value, the second clutch torque capacity command value is set to the motor torque command. An operation of decreasing the value more slowly than the increasing rate of the value (so that the decreasing rate becomes smaller) is performed.

  Therefore, in the engine start control by the sixth operation, when the engine start request (time t1) is issued after switching from the “EV mode” to the “engine start mode”, the motor torque command value and the second clutch torque capacity command value are set. Until the value becomes the same value, the second clutch torque capacity command value is maintained at a constant value equal to or higher than the EV drive torque phase immediately before the mode change. If the second clutch CL2 does not slip when both command values become the same value, the second clutch torque capacity command value is decreased at a gentler gradient than the increase rate of the motor torque command value.

  By this sixth operation, the presence or absence of slip is determined when the motor torque command value and the second clutch torque capacity command value become the same value, and if there is no slip, the second clutch torque capacity command value is decreased. The slip is urged. That is, when the characteristic fluctuation (variation) of the second clutch torque capacity is ignored, the point at which the motor torque command value becomes equal to the second clutch torque capacity command value is set as the slip start point, and the motor torque command value increases. Depending on the situation, the slip proceeds. Therefore, the operation for prompting the occurrence of slip can be referred to as a correction operation for characteristic variation of the second clutch torque capacity. As a result, regardless of the characteristic fluctuation of the second clutch torque capacity, the vehicle acceleration closer to the target after the slip transition is realized by the characteristic fluctuation correcting operation.

[Engine start control action by seventh operation]
FIG. 23 is an A part enlarged time chart of FIG. 15 showing characteristics of the second clutch torque capacity / motor torque from the engine start request (time t1) to the slip detection (time t2) according to the seventh operation. Hereinafter, the engine start control action by the seventh operation will be described with reference to FIG.

  As shown in FIG. 23, the seventh operation pays attention to the motor torque command value that can ensure engine start, and is equal to or greater than the difference value (= maximum drive torque) between the maximum motor torque and the cranking torque that can be output. If slip does not occur even when the value becomes, the operation of gradually decreasing the second clutch torque capacity command value from the increasing rate of the motor torque command value is performed. That is, the conditions for starting to decrease the second clutch torque capacity command value are different from the sixth operation focusing on the intersection timing of the motor torque command value at which the occurrence of slip is predicted to start and the second clutch torque capacity command value.

  Therefore, in the engine start control by the seventh operation, when the engine start request (time t1) is issued after switching from the “EV mode” to the “engine start mode”, the maximum motor torque that can be output as the motor torque command value is Until the cranking torque difference value is reached, the second clutch torque capacity command value is maintained at a constant value equal to or greater than the EV drive torque phase immediately before the mode change. When the second clutch CL2 does not slip when the motor torque command value becomes the difference value, the second clutch torque capacity command value is decreased with a gentler gradient than the increase rate of the motor torque command value.

  By this seventh operation, the presence or absence of slip is determined when the motor torque command value reaches the difference value. If there is no slip, the second clutch torque capacity command value is decreased to generate slip. . In other words, if the characteristic fluctuation (variation) of the second clutch torque capacity is ignored, the maximum motor torque is already detected when the slip is already detected when the motor torque command value becomes the difference value and the slip cannot be detected early. Even if is output, cranking torque cannot be secured. Therefore, the operation for prompting the occurrence of slip can be referred to as a correction operation for characteristic variation of the second clutch torque capacity. As a result, regardless of the characteristic variation of the second clutch torque capacity, the subsequent engine start is performed more smoothly by the characteristic variation correcting operation.

Next, the effect will be described.
In the control device for the FR hybrid vehicle of the first embodiment, the effects listed below can be obtained.

  (1) The first clutch CL1 that intermittently connects the engine Eng and the motor generator MG, and the second clutch CL2 that intermittently connects the motor generator MG and the driving wheels (left and right rear wheels RL, RR). A hybrid vehicle mode (HEV mode) that travels with the power of the engine Eng and the motor generator MG with the CL1 engaged, and an electric vehicle mode that travels only with the power of the motor generator MG with the first clutch CL1 open ( In the control device for an FR hybrid vehicle that travels by switching between an EV mode) and an engine start mode in which engine cranking is performed using the power of the same motor generator MG while traveling only with the power of the motor generator MG, Torque capacity command value to the second clutch CL2 after switching from the electric vehicle mode to the engine start mode The motor torque command value to the motor generator MG is gradually increased until a slip of the second clutch CL2 is detected until the slip of the second clutch CL2 is detected. Engine start control means (FIG. 2) for starting the engine Eng by shifting the one clutch CL1 to the engagement side is provided. For this reason, when switching from the electric vehicle mode to the engine start mode, the engine start can be accelerated and the G omission can be reliably prevented.

  (2) The engine start control means (FIG. 2) gradually increases the motor torque command value to the motor generator MG after the torque capacity of the second clutch CL2 becomes substantially constant. For this reason, it is possible to prevent the second clutch torque capacity from fluctuating after shifting to the slip state, and to prevent the vehicle acceleration from decreasing between the slip detection and the completion of the engine start control.

  (3) The engine start control means (FIG. 2), after switching from the electric vehicle mode to the engine start mode, outputs a motor torque command value to the motor generator MG to a torque capacity command to the second clutch CL2. Stepwise increase to a predetermined value below the value. For this reason, the second clutch CL2 can easily start slipping, and the time until slip detection can be shortened.

  (4) An accelerator opening detecting means (accelerator opening sensor 16) for detecting the accelerator opening APO is provided, and the engine start control means (FIG. 2) increases the detected motor opening APO as the detected accelerator opening APO increases. Increase the motor torque command value to MG per unit time. For this reason, if the accelerator opening APO is large and the driver wants to start the engine immediately, the motor torque is quickly increased and slipped quickly, and the engine is driven at an early timing according to the driver's intention to increase driving force or acceleration. Startup can be achieved.

  (5) An accelerator opening detecting means (accelerator opening sensor 16) for detecting the accelerator opening APO is provided, and the engine start control means (FIG. 2) increases the second accelerator opening APO as the detected accelerator opening APO increases. Decrease the torque capacity command value to the clutch CL2. For this reason, when the accelerator opening APO is large and the driver wants to start the engine immediately, the second clutch torque capacity command value is decreased, the second clutch torque capacity is decreased, and the driver slips quickly. The engine can be started at an early timing according to the intention of increasing the power or the intention of acceleration.

  (6) The engine start control means (FIG. 2) is configured such that the second clutch CL2 does not slip even if the motor torque command value to the motor generator MG exceeds the torque capacity command value to the second clutch CL2. The torque capacity command value for the second clutch CL2 is decreased at a gentler gradient than the increasing gradient of the motor torque command value for the motor generator MG. For this reason, regardless of the characteristic variation of the second clutch torque capacity, the vehicle acceleration closer to the target after the slip transition can be realized by the correction operation of the characteristic variation.

  (7) The engine start control means (FIG. 2) is configured such that the motor torque command value to the motor generator MG is a maximum drive torque based on a difference value between the maximum motor torque that can be output in the electric vehicle mode and the cranking torque. If the second clutch CL2 does not slip even if it exceeds, the torque capacity command value for the second clutch CL2 is decreased at a gentler gradient than the increase gradient of the motor torque command value for the motor generator MG. For this reason, regardless of the characteristic variation of the second clutch torque capacity, the subsequent engine start can be smoothly performed by the characteristic variation correction operation.

  As mentioned above, although the control apparatus of the hybrid vehicle of this invention was demonstrated based on Example 1, it is not restricted to this Example 1 about a concrete structure, The invention which concerns on each claim of a claim Design changes and additions are permitted without departing from the gist of the present invention.

  In the first embodiment, the motor torque command value is gradually increased from the engine start request time (first operation), and the motor torque command value is gradually increased from the time when the second clutch torque capacity becomes substantially constant (second operation). Operation), the motor torque command value is raised from the time when the engine start is requested until the CL2 torque capacity is substantially constant (third operation), and the increasing gradient of the motor torque command value is determined by the accelerator opening (fourth operation). The second clutch torque capacity command value is determined by the accelerator opening (fifth operation), and the second clutch torque capacity command value is decreased from the time when both command values become the same value (sixth operation). Each operation example of decreasing the second clutch torque capacity command value (seventh operation) from the time when becomes the difference value is shown. However, the specific operation examples are not limited to these, and other information may be used, the motor torque command value may be increased by a stepwise characteristic, or the motor torque command value may be increased by a curve characteristic. good. In short, after switching from the “EV mode” to the “engine start mode”, the torque capacity command value of the second clutch CL2 is made constant at a value equal to or greater than the EV drive torque phase immediately before the mode change, and the slip of the second clutch CL2 is reduced. An example in which the motor torque command value to the motor generator MG is gradually increased until detection is included in the present invention.

  In the first embodiment, an example of application to an FR hybrid vehicle equipped with one motor generator MG has been shown. However, the control device for an FR hybrid vehicle or FF hybrid vehicle equipped with two or more motor generators MG is also used. Can be applied. In the first embodiment, an example in which the frictional engagement element built in the automatic transmission is used as the second clutch is shown. However, the hybrid drive system is provided with an independent second clutch at the upstream position or the downstream position of the transmission. It can also be applied to vehicles.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall system diagram illustrating a parallel-type FR hybrid vehicle (an example of a hybrid vehicle) by rear wheel drive to which a control device according to a first embodiment is applied. It is a flowchart which shows the engine starting control process performed in the integrated controller 10 of FR hybrid vehicle to which the control apparatus of Example 1 was applied. It is a figure which shows an example of the target drive torque calculation map which calculates a target drive torque by using the accelerator opening APO and the vehicle speed VSP as parameters. It is a figure which shows an example of the map which calculates the target slip rotation speed in HEV mode. It is a figure which shows an example of the map which calculates the target slip rotation speed (increment) in engine starting mode. It is a control block diagram which shows a 2nd clutch rotational speed control system. It is a figure which shows an example of a 2nd clutch torque capacity-hydraulic pressure conversion map. It is a figure which shows an example of a 2nd clutch torque oil pressure-current conversion map. It is a flowchart which shows the target control mode calculation process (step S4 of FIG. 2) of each clutch performed with the integrated controller 10 of FR hybrid vehicle to which the control apparatus of Example 1 was applied. It is a figure which shows an example of the relationship characteristic of the clutch torque capacity | capacitance of a 1st clutch, a clutch stroke, and a diaphragm spring reaction force. It is a flowchart which shows the 1st clutch electric current command value calculation process (step S19 of FIG. 2) performed in the integrated controller 10 of FR hybrid vehicle to which the control apparatus of Example 1 was applied. It is a control block diagram which shows a 1st clutch stroke control system. It is a time chart which shows each characteristic of accelerator opening degree, motor rotation speed, 2nd clutch output rotation speed, engine rotation speed, 2nd clutch torque capacity, motor torque, and motor control state in an engine start control comparative example. 6 is a time chart showing characteristics of an accelerator opening, a second clutch torque capacity, a motor torque, a rotation speed, a slip rotation speed, and an acceleration representing problems in a comparative example of engine start control. Characteristics of accelerator opening, motor rotation speed, second clutch output rotation speed, engine rotation speed, second clutch torque capacity, motor torque, and motor control state in engine start control in the control apparatus for the FR hybrid vehicle of the first embodiment It is a time chart which shows. FIG. 16 is an A part enlarged time chart of FIG. 15 showing characteristics of the second clutch torque capacity and motor torque from the engine start request (time t1) to the slip detection (time t2) according to the first operation. 3 is a time chart showing characteristics of accelerator opening, second clutch torque capacity, motor torque, rotation speed, slip rotation speed, and acceleration in engine start control of the FR hybrid vehicle of the first embodiment. FIG. 16 is an A part enlarged time chart of FIG. 15 showing characteristics of the second clutch torque capacity and motor torque from the engine start request (time t1) to the slip detection (time t2) due to the second operation. FIG. 16 is an A part enlarged time chart of FIG. 15 illustrating characteristics of the second clutch torque capacity and motor torque from the engine start request (time t1) to the slip detection (time t2) according to the third operation. FIG. 16 is an enlarged time chart of a portion A in FIG. 15 showing characteristics of the second clutch torque capacity and motor torque from the engine start request (time t1) to the slip detection (time t2) according to the fourth operation. FIG. 16 is an enlarged time chart of part A of FIG. 15 showing characteristics of the second clutch torque capacity and motor torque from the engine start request (time t1) to the slip detection (time t2) according to the fifth operation. FIG. 16 is an A part enlarged time chart of FIG. 15 showing characteristics of the second clutch torque capacity and motor torque from the engine start request (time t1) to the slip detection (time t2) according to the sixth operation. FIG. 16 is an A part enlarged time chart of FIG. 15 illustrating characteristics of the second clutch torque capacity and motor torque from the engine start request (time t1) to the slip detection (time t2) according to the seventh operation.

Explanation of symbols

Eng engine
FW flywheel
CL1 1st clutch
MG motor generator
CL2 2nd clutch
AT automatic transmission
PS propeller shaft
DF differential
DSL left drive shaft
DSR right drive shaft
RL Left rear wheel (drive wheel)
RR Right rear wheel (drive wheel)
DESCRIPTION OF SYMBOLS 1 Engine controller 2 Motor controller 3 Inverter 4 Battery 5 1st clutch controller 6 1st clutch hydraulic unit 7 AT controller 8 2nd clutch hydraulic unit 9 Brake controller 10 Integrated controller 11 CAN communication line 12 Engine speed sensor 13 Resolver 14 Hydraulic actuator 14a piston 15 first clutch stroke sensor 16 accelerator opening sensor (accelerator opening detecting means)
17 Vehicle speed sensor

Claims (7)

A first clutch for intermittently connecting the engine and the motor generator, and a second clutch for intermittently connecting the motor generator and the drive wheel,
A hybrid vehicle mode in which the first clutch is engaged and the engine and the motor generator are driven, an electric vehicle mode in which the first clutch is released and only the motor generator is driven; In a hybrid vehicle control device that travels by switching between an engine start mode in which engine cranking is performed using the power of the same motor generator while traveling only with power,
After switching from the electric vehicle mode to the engine start mode, the torque capacity command value to the second clutch is made constant at a value equal to or greater than the electric vehicle driving torque phase immediately before the mode switching, and the slip of the second clutch is detected. The engine is provided with engine start control means for gradually increasing the motor torque command value to the motor generator until a slip is detected and shifting the first clutch to the engaged side when the slip is detected. Vehicle control device. In the hybrid vehicle control device according to claim 1,
The hybrid vehicle control apparatus, wherein the engine start control means gradually increases a motor torque command value to the motor generator after the torque capacity of the second clutch becomes substantially constant. In the hybrid vehicle control device according to claim 2,
After the engine start control unit switches from the electric vehicle mode to the engine start mode, the engine start control means steps the motor torque command value to the motor generator to a predetermined value not more than the torque capacity command value to the second clutch. A control apparatus for a hybrid vehicle, characterized in that the controller is increased. In the control apparatus of the hybrid vehicle described in any one of Claim 1- Claim 3,
Accelerator opening detection means for detecting the accelerator opening is provided,
The control device for a hybrid vehicle, wherein the engine start control means increases an increase amount per unit time of a motor torque command value to the motor generator as the detected accelerator opening is larger. In the hybrid vehicle control device according to any one of claims 1 to 4,
Accelerator opening detection means for detecting the accelerator opening is provided,
The engine start control means reduces the torque capacity command value to the second clutch as the detected accelerator opening is larger, the control apparatus for a hybrid vehicle. In the control apparatus of the hybrid vehicle described in any one of Claim 1- Claim 5,
If the motor torque command value to the motor generator exceeds the torque capacity command value to the second clutch and the second clutch does not slip, the engine start control means has a torque capacity command to the second clutch. A control apparatus for a hybrid vehicle, wherein a value is decreased at a gentler slope than an increase slope of a motor torque command value to the motor generator. In the control apparatus of the hybrid vehicle described in any one of Claim 1- Claim 5,
The engine start control means is configured so that the second clutch is engaged even when a motor torque command value to the motor generator exceeds a maximum drive torque based on a difference value between a maximum motor torque and a cranking torque that can be output during driving in the electric vehicle mode. When the vehicle does not slip, the torque capacity command value for the second clutch is decreased at a gentler gradient than the increase gradient of the motor torque command value for the motor generator.

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