JP6477177B2 - Control device for hybrid vehicle - Google Patents

Description

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

  Patent Document 1 describes a hybrid vehicle having a first clutch that connects and disconnects torque transmission between an engine and a motor, and a second clutch that connects and disconnects torque transmission between a motor and drive wheels. In this hybrid vehicle, when there is an engine start request, the target second clutch torque capacity is set lower than the target drive torque of the vehicle, and when slip-in (slip state of the second clutch) is detected, the first clutch is engaged. Has started cranking the engine. When the cranking is started, the second clutch torque capacity is corrected to the target drive torque.

JP 2010-030486 A

In the above prior art, the second clutch torque capacity is corrected during cranking in which the control accuracy of the second clutch torque capacity is lowered. For this reason, the acceleration of the vehicle varies as the second clutch torque capacity varies during cranking. The driver's unexpected acceleration fluctuation gives the driver a sense of incongruity.
An object of the present invention is to provide a control device for a hybrid vehicle that can suppress acceleration fluctuations at the time of engine startup unexpected by the driver.

In the present invention, when it is determined that the responsiveness to the engine start request is unnecessary, the decrease gradient of the target second clutch torque capacity when the second clutch is slipped is smaller than when the responsiveness is determined to be necessary. At the same time, when the slip of the second clutch is detected , the torque capacity of the second clutch is corrected up to the target drive torque of the vehicle, and cranking is started after the correction is completed.

  Therefore, since the second clutch torque capacity does not fluctuate during cranking, it is possible to suppress acceleration fluctuations at the time of engine start unexpected by the driver.

1 is a diagram showing a configuration diagram of a power train of a hybrid vehicle of Example 1. FIG. It is a block diagram of each controller of a power train. 3 is a control block diagram of an integrated controller 21. FIG. 4 is a flowchart showing a flow of control in the integrated controller 21 when shifting from the EV mode to the HEV mode. It is a figure which shows the responsiveness necessity determination method based on a driver | operator's acceleration intention. It is a figure which shows the responsiveness necessity determination method based on the parameter of the vehicle which determines the necessity for engine starting irrespective of a driver | operator's acceleration intention. It is a figure which shows the responsiveness necessity determination method at the time of automatic driving | operation. It is a control transition diagram at the time of shifting from the EV mode to the HEV mode. It is a figure which shows the correction completion determination method of 2nd clutch torque capacity. It is a time chart which shows the operation | movement at the time of transfer from EV mode to HEV mode without accel increase in the conventional control. 6 is a time chart showing an operation at the time of transition from the EV mode to the HEV mode without an accelerator increase in the first embodiment. It is a time chart which shows the operation | movement at the time of the shift from EV mode to HEV mode without the accelerator increase in Example 2. FIG.

[Example 1]
[Power train]
FIG. 1 is a diagram illustrating a configuration diagram of a power train of the hybrid vehicle according to the first embodiment.
The hybrid vehicle includes an engine 1 that is a driving force source of an internal combustion engine, and a motor generator (hereinafter referred to as a motor) 2 that is a driving force source that generates a driving force by electric power. The engine 1 and the motor 2 are arranged in series in the traveling direction of the vehicle. The outputs of the engine 1 and the motor 2 are shifted by an automatic transmission (hereinafter referred to as “AT”) 3 and output to a rear wheel 5 that is a driving wheel via a differential gear 4. The motor 2 is configured by a synchronous motor using a permanent magnet for the rotor, for example. The motor 2 is power-running or regeneratively driven according to the driving scene.

A first clutch 8 is interposed between the engine output shaft 6 and the motor input shaft 7. The first clutch 8 enables connection / disconnection of power between the engine 1 and the motor 2. The first clutch 8 is constituted by, for example, a dry single plate clutch or a wet multi-plate clutch capable of changing the torque capacity by continuously controlling the clutch operating oil pressure with a proportional solenoid valve or the like.
A second clutch 9 is provided in the AT 3. The second clutch 9 can connect / disconnect power transmission between the engine 1 and the motor 2 and the rear wheel 5. The second clutch 9 uses either an existing forward speed selection friction element or a reverse speed selection friction element in the AT 3. The second clutch 9 is not necessarily one friction element, and any friction element corresponding to the gear position can be the second clutch 9. Similar to the first clutch 8, the second clutch 9 can continuously change the torque capacity. The second clutch 9 is composed of a wet multi-plate clutch or a dry single-plate clutch that can change the torque capacity by continuously controlling the clutch hydraulic pressure with a proportional solenoid valve, for example.

The AT 3 selectively engages and disengages a plurality of friction elements (such as a clutch and a brake), and selects a transmission path by a combination of these friction elements to determine a gear position. Accordingly, the AT 3 shifts the rotation input from the AT input shaft 10 to a gear ratio corresponding to the selected gear and outputs it to the AT output shaft 11. The AT 3 may be composed of a stepped transmission such as a forward seventh speed and a reverse first speed, or may be a continuously variable transmission.
In the vicinity of the engine output shaft 6, an engine rotation sensor 12 for detecting the engine speed is provided. In the vicinity of the motor input shaft 7, a motor rotation sensor 13 for detecting the motor rotation speed is provided.
In the vicinity of the AT input shaft 10, an AT input rotation sensor 14 for detecting the AT input rotation speed is provided. In the vicinity of the AT output shaft 11, an AT output rotation sensor 15 for detecting the AT output rotation speed (vehicle speed) is provided.
A stroke sensor 16 that detects the stroke of the first clutch 8 is provided in the vicinity of the first clutch 8.

FIG. 2 is a block diagram of each controller of the power train. The hybrid vehicle has an integrated controller (engine start control means) 21, an engine controller 22, and a motor controller 23.
The integrated controller 21 determines the engine speed, motor speed, AT input speed, AT output speed, the voltage of the battery 17 (battery voltage) detected by the voltage sensor 20, the accelerator opening detected by the APO sensor 18, etc. Input each sensor value. The integrated controller 21 determines the operating point of the power train in accordance with each sensor value and the SOC of the battery 17, and selects a traveling mode that can realize the driving force desired by the driver. The battery SOC can be obtained from the integrated value of current when the vehicle is traveling. When the vehicle is stopped, it can be obtained from a map showing the relationship between current and voltage according to the battery SOC. The integrated controller 21 outputs the target motor torque or the target motor rotation speed to the motor controller 23. The integrated controller 21 outputs the target engine torque to the engine controller 22. The integrated controller 21 outputs drive signals to the solenoid valve 24 that controls the hydraulic pressure of the first clutch 8 and the solenoid valve 25 that controls the hydraulic pressure of the second clutch 9.

  The engine controller 22 controls the engine 1 so that the engine torque becomes the target engine torque. When performing torque control of the motor 2, the motor controller 23 controls the motor 2 so that the torque output from the motor 2 becomes the target motor torque. When performing the rotational speed control of the motor 2, the motor controller 23 controls the motor 2 so that the rotational speed of the motor 2 becomes the target motor rotational speed. The motor controller 23 controls the motor 2 so that the torque output from the motor 2 becomes the target power generation torque in cooperation with the engine controller 22 during regeneration of the motor 2. The inverter 19 converts the direct current from the battery 17 into an alternating current during power running operation of the motor 2 and supplies the alternating current to the motor 2, and converts the alternating current generated by the motor 2 into direct current during the regenerative operation. Charge.

[Driving mode]
The power train of the hybrid vehicle has three travel modes according to the engaged state of the first clutch 8.
(EV mode)
The first traveling mode is an electric traveling mode (hereinafter referred to as “EV mode”) in which traveling is performed using only the motor 2 as a power source. For example, the EV mode is required at low loads and low vehicle speeds including when starting from a stopped state. In the EV mode, since the power from the engine 1 is unnecessary, the fuel injection is stopped (fuel cut) and stopped, and the first clutch 8 is released. In the EV mode, the motor 2 is torque controlled so that the motor torque becomes the target drive torque. Further, the second clutch 9 is engaged and the AT 3 is set in the power transmission state. The torque capacity of the second clutch 9 is set to a capacity obtained by adding a predetermined margin torque to the target driving torque in consideration of variations in the torque capacity. In this state, the vehicle is driven only by the motor 2.

(HEV mode)
The second travel mode is a hybrid travel mode (hereinafter referred to as “HEV mode”) that travels as a power source for both the engine 1 and the motor 2. For example, the HEV mode is required when the accelerator opening is high or when it is difficult to continue the EV mode from the viewpoint of system protection. In the HEV mode, the first clutch 8 and the second clutch 9 are engaged and the AT 3 is in a power transmission state. In this state, both the output rotation from the engine 1 and the output rotation from the motor 2 are input to the input shaft 3a of the transmission, and hybrid traveling by both is performed. When shifting from the EV mode to the HEV mode, the first clutch 8 is engaged, and the engine 1 is cranked using the torque of the motor 2 to start the engine 1. At this time, smooth mode switching can be realized by variably controlling the torque capacity of the first clutch 8 to perform slip engagement.

(WSC mode)
The third travel mode is a slip travel mode (hereinafter referred to as “WSC mode”) in which the first clutch 8 is engaged and the second clutch 9 is slip-controlled to travel with the power of the engine 1 and the motor 2. In the WSC mode, even when the load is low and the vehicle speed is low, especially when the battery SOC is low or the engine water temperature is low, the engine 1 is also started and creep running is realized. The WSC mode is a mode that can output driving force while starting the engine 1 when the engine 1 starts from a stopped state. The second clutch 9 can also function as a so-called starting clutch. When the vehicle is started, the torque capacity of the second clutch 9 is variably controlled and slip-engaged to absorb torque fluctuations and start smoothly even in a power train that does not include a torque converter.

[Control system]
FIG. 3 is a control block diagram of the integrated controller 21.
The accelerator opening speed calculating unit 31 calculates the accelerator opening speed by differentiating the accelerator opening. The second clutch slip rotation speed calculation unit 32 calculates the second clutch slip rotation speed from the AT input rotation speed and the AT output rotation speed. The target drive torque calculation unit 33 calculates the target drive torque of the vehicle using the target drive torque map from the accelerator opening and the vehicle speed. The engine start request determination unit 34 determines whether or not there is an engine start / stop request based on the accelerator opening, the accelerator opening speed, the battery SOC, the vehicle speed, the engine water temperature, the vehicle speed, and the like.

  The engine start method switching unit 35 is configured to start the engine in response to an engine start request based on the accelerator opening, the accelerator opening speed, the battery SOC, the vehicle speed, the engine water temperature, the vehicle speed, the target drive torque, the control state of the motor 2 and the second clutch 9. The necessity of the responsiveness is determined, and the engine starting method is switched according to the determination result. The target travel mode calculation unit 36 selects a target travel mode from the EV mode, the HEV mode, and the WSC mode based on the target drive torque, the presence / absence of an engine start / stop request, and the engine start method. The transient travel mode management unit 37 manages a transient state for switching the travel mode from the current travel mode toward the target travel mode based on the engine start method, the target travel mode, and the second clutch slip rotation speed.

  The second clutch slip control management unit 38 is a motor related to the second clutch slip control when the travel mode is not switched in the EV mode and the WSC mode based on the engine start method, the second clutch slip rotation speed, and the target travel mode. 2 and the control state of the second clutch 9 are managed. The motor control mode selection unit 39 selects the control mode (rotational speed control, torque control) of the motor 2 based on the control state of the motor 2. The motor torque determination unit 40 determines a target motor torque based on the control state of the motor 2. The motor rotation speed control unit 41 determines a target motor rotation speed based on the control state of the motor 2 and the motor rotation speed. The second clutch torque capacity correction unit 42 corrects the second clutch torque capacity to match the target drive torque based on the control state of the second clutch 9, the engine start method, the motor speed, and the like. Here, “match” means a state in which the deviation between the second clutch torque capacity and the target drive torque is equal to or less than a predetermined value.

  The first clutch torque capacity determination unit 43 determines a target first clutch torque capacity based on the control state of the first clutch 8. The first clutch stroke control unit 44 calculates a first clutch stroke for obtaining a target first clutch torque capacity based on the control state of the first clutch 8 and the first clutch stroke. The engine torque control unit 45 calculates a target engine torque based on the control state of the engine 1, the engine start method, and the target travel mode. The second clutch torque capacity control unit 46 generates a command signal for the solenoid valve 25 that obtains the target second clutch torque capacity based on the target second clutch torque capacity, the engine starting method, and the target drive torque. The first clutch hydraulic control unit 47 generates a command signal to the solenoid valve 24 that obtains the first clutch stroke.

[EV → HEV mode engine start control]
FIG. 4 is a flowchart showing a control flow in the integrated controller 21 when shifting from the EV mode to the HEV mode.
In step S01, data is received from each controller.
In step S02, each sensor value is read. The received data and the input sensor values are used as appropriate in the following steps.
In step S03, the target drive torque calculation unit 33 calculates the target drive torque.
In step S04, the engine start request determination unit 34 determines whether there is an engine start request. If there is no engine start request, this control is terminated.
In step S05, the engine start method switching unit 35 determines whether or not the engine start response to the engine start request is necessary.

In step S06, the target travel mode calculation unit 36 selects a target travel mode.
In step S07, the transient travel mode management unit 37 manages a transient state for switching the travel mode.
In step S08, the second clutch slip control management unit 38 manages the control states of the motor 2 and the second clutch 9 related to the second clutch slip control when the travel mode is not switched.
In step S09, the motor torque determination unit 40 determines the target motor torque.
In step S10, the second clutch torque capacity correction unit 42 calculates the target input rotational speed of the second clutch 9 based on the target driving torque and the AT output rotational speed.
In step S11, the engine torque control unit 45 calculates a target engine torque.

In step S12, the first clutch torque capacity determination unit 43 calculates a target first clutch torque capacity.
In step S13, the second clutch torque capacity correction unit 42 calculates a target second clutch torque capacity based on the target motor torque and the target input rotational speed.
In step S14, the first clutch stroke control unit 44 calculates the first clutch stroke.
In step S15, the second clutch torque capacity correction unit (second clutch torque capacity estimating means) 42 estimates the second clutch torque capacity, and the second clutch torque capacity correcting unit 42 eliminates the deviation between the target drive torque and the estimated second clutch torque capacity. 2 Correct the clutch torque capacity.
In step S16, each calculated data is transmitted to each controller.

[Determining whether engine responsiveness is required]
Next, engine start response determination in the engine start method switching unit 35 will be described.
FIG. 5 is a diagram showing a responsiveness necessity determination method based on the driver's intention to accelerate. As shown in the map of FIG. 5, basically, when the accelerator opening (APO) is high, responsiveness is required, and when the accelerator opening is low, it is determined that responsiveness is unnecessary. If the accelerator opening speed (ΔAPO) is large on the negative side even if the acceleration is high, it is determined that the responsiveness is unnecessary, and if the accelerator opening speed is large on the positive side even if the accelerator opening is low, the responsiveness is necessary. Is determined. That is, when the driver has an intention to accelerate, it is determined that responsiveness is necessary, and when there is no intention to accelerate, it is determined that responsiveness is unnecessary. In the map of FIG. 5, a hysteresis for suppressing hunting is set at the boundary between the two regions. Further, the position of the boundary is changed according to the vehicle speed so that the region where it is determined that the responsiveness is unnecessary is enlarged as the vehicle speed is lower. Instead of the vehicle speed or in addition to the vehicle speed, the current speed ratio of AT3 may be used, and the region where the responsiveness is determined to be unnecessary may be increased as the speed ratio is larger.

  FIG. 6 is a diagram showing a responsiveness necessity determination method based on vehicle parameters that determine whether or not the engine needs to be started regardless of the driver's intention to accelerate. First, when the battery SOC is less than the threshold, it is determined that responsiveness is necessary, and when the battery SOC is equal to or greater than the threshold, it is determined that responsiveness is unnecessary. Further, when the battery voltage is less than the threshold, it is determined that responsiveness is necessary, and when the battery voltage is equal to or higher than the threshold, it is determined that responsiveness is unnecessary. Further, when the engine water temperature is lower than the low temperature threshold and higher than the high temperature threshold, it is determined as necessary, and when the engine water temperature is higher than the low temperature threshold and lower than the high temperature threshold, it is determined as unnecessary.

  The engine start method switching unit 35 determines that the necessity of the final engine start responsiveness based on the vehicle parameter that determines the necessity of engine start is necessary when at least one of the above three determination results is necessary. However, when all are unnecessary, it is determined as unnecessary. In other words, when starting the engine not for the driver's request but for the purpose of system protection, vehicle parameters (battery SOC, battery voltage, engine water temperature, etc.) that determine whether or not the engine needs to be started are promptly determined from the viewpoint of system protection. It is determined whether the engine needs to be started. Each of the above threshold values is changed according to the vehicle speed so that the region where it is determined that the responsiveness is unnecessary is increased as the vehicle speed is lower. Instead of the vehicle speed or in addition to the vehicle speed, the current speed ratio of AT3 may be used, and each threshold value may be changed so that the region where it is determined that the responsiveness is unnecessary is increased as the speed ratio is larger. Here, as the battery SOC, the battery voltage, and the engine water temperature, a look-ahead value predicted from the current value may be used.

  FIG. 7 is a diagram illustrating a method for determining whether or not responsiveness is required during automatic driving. When vehicle speed control is performed as automatic driving, the necessity of responsiveness is determined based on the target vehicle speed and the vehicle speed deviation (vehicle speed-target vehicle speed). Basically, if the vehicle speed deviation is positive, it is determined that responsiveness is not required, and if the vehicle speed deviation is negative, it is determined that responsiveness is required, but the absolute value is small even if the vehicle speed deviation is negative. In this case, it is determined that responsiveness is unnecessary. Hysteresis is set at the boundary between the two regions. Further, when inter-vehicle distance control is performed as automatic driving, the necessity of responsiveness is determined based on the inter-vehicle distance from the preceding vehicle and the vehicle speed of the host vehicle. When the inter-vehicle distance is long, it is determined that responsiveness is necessary, and when the inter-vehicle distance is short, it is determined that responsiveness is unnecessary. Hysteresis is set at the boundary between the two regions. The engine start method switching unit 35 determines whether or not the final engine start responsiveness based on the automatic operation is necessary when at least one of the above two determination results is necessary, and when both are not necessary Is determined to be unnecessary.

[Transient running mode management and second clutch slip control management]
Next, the transient travel mode management and the second clutch slip control management at the time of engine start request in the transient travel mode management unit 37 and the second clutch slip control management unit 38 will be described.
FIG. 8 is a control transition diagram when shifting from the EV mode to the HEV mode.
(Slip-in control at start-up)
If it is determined that there is an engine start request during EV mode and engine start responsiveness is required, or if it is determined that engine responsiveness is required during EV slip-in control described later, slip-in Transition to slip-in control at start-up for early start-up. In the start-in slip-in control, the motor 2 controls the torque and increases the target motor torque with a constant gradient. The target second clutch torque capacity is reduced stepwise to a capacity obtained by subtracting a predetermined margin torque from the target drive torque in consideration of variations in torque capacity. The first clutch 8 is released and the engine 1 is fuel cut.

(EV slip-in control)
When it is determined that there is an engine start request during the EV mode and the responsiveness of the engine start is not required, the ECU shifts to EV slip-in control aiming to suppress acceleration fluctuation of the vehicle. In the EV slip-in control, the motor 2 is torque-controlled, and the target motor torque is gradually increased with a constant gradient. The target second clutch torque capacity is gradually decreased with a constant gradient. The first clutch 8 is released and the engine 1 is fuel cut.

(EV slip control)
When slip-in (slip state of the second clutch 9) is detected during EV slip-in control, the process shifts to EV slip control in which the second clutch torque capacity is corrected to match the target drive torque. In the EV slip control, the motor 2 controls the rotation speed, and the target motor rotation speed is set to a rotation speed obtained by adding a predetermined EV target slip rotation speed to the AT input rotation speed. The target slip rotational speed at the time of EV is a rotational speed at which the second clutch 9 can maintain a μ slip state with a slight slip amount. The target second clutch torque capacity is a value obtained by adding the correction torque to the target drive torque. The correction torque is a value proportional to the deviation between the target drive torque and the estimated second clutch torque capacity. The first clutch 8 is released and the engine 1 is fuel cut.

(Cranking control)
When slip-in is detected during start-up slip-in control, when it is determined that engine responsiveness is required during EV slip control, or when correction of the second clutch torque capacity is completed during EV slip control If it is determined, the process proceeds to cranking control. In the cranking control, the motor 2 controls the rotation speed, and the target motor rotation speed is set to a rotation speed obtained by adding a predetermined engine start target slip rotation speed (> EV target slip rotation speed) to the AT input rotation speed. The target slip rotation speed at engine start is set to a rotation speed at which the engine 1 can be cranked. Note that the target motor speed is set to the lower limit of the engine 1 idle speed. The second clutch torque capacity is gradually increased with a constant gradient using the target drive torque as a target value, except when the correction of the second clutch torque capacity is completed. On the other hand, when the correction of the second clutch torque capacity is completed, the target second clutch torque capacity calculated last in the EV slip control is held. The first clutch 8 is engaged, and the engine 1 resumes fuel injection.
It should be noted that an appropriate initial value is set immediately after the control switching so that the target second clutch torque capacity does not become discontinuous at the time of switching each control described above.

[Second clutch torque capacity correction completion determination]
Next, the correction completion determination of the second clutch torque capacity in the second clutch torque capacity correction unit 42 will be described.
FIG. 9 is a diagram illustrating a correction completion determination method for the second clutch torque capacity. The second clutch torque capacity correction unit 42 determines that the correction of the second clutch torque capacity is completed when the state where the deviation between the target drive torque and the estimated second clutch torque capacity is equal to or less than the predetermined value continues for the first predetermined time. judge. The estimated second clutch torque capacity is calculated using a disturbance observer using a deviation between the motor reference response and the motor rotational speed, a fluctuation in the motor rotational speed, and the motor torque. An example is shown below.
T _CL2 ^ = -H (s) * {T _m ^* -(ω _{m_ref} -ω _m ) / G _comp (s)} + H (s) * s / G _p (s) * ω _m
T _CL2 ^ is the estimated second clutch torque capacity, H (s) is the disturbance observer filter, ω _{m_ref} is the motor reference response, ω _m is the motor speed, G _comp (s) is the compensator for motor speed control, G _p (s) is a motor plant.

[Acceleration fluctuation at engine start]
FIG. 10 is a time chart showing an operation at the time of transition from the EV mode to the HEV mode without accel increase in the conventional control.
At time t1, since it is determined that there is an engine start request, the target second clutch torque capacity is decreased stepwise. At this time, in order to surely and quickly slip the second clutch in, the second clutch torque capacity is set to a torque capacity lower than the AT input torque (motor torque) (target drive torque−margin 2) in consideration of variations in torque capacity. ). Here, in order to prevent the second clutch from slipping until just before time t1, the second clutch is operated with a torque capacity (target drive torque + margin 1) higher than the AT input torque (motor torque) in consideration of variations in torque capacity. It is concluded. Therefore, a difference of margin 1 + margin 2 appears in the target second clutch torque capacity before and after time t1. As a result, the driving force of the vehicle is reduced due to the torque step between the target driving torque and the second clutch torque capacity, and the vehicle is decelerating.

  Since slip-in is detected at time t2, the first clutch is engaged and engine cranking is started. Even when the second clutch torque capacity is corrected to the target drive torque, the driving force of the vehicle increases due to a torque step between the target drive torque and the second clutch torque capacity, and acceleration is generated in the vehicle. Further, in the conventional control, the second clutch torque capacity is corrected during cranking. Here, the second clutch torque capacity is corrected by estimating the second clutch torque capacity using the motor torque and the motor rotation speed so that the deviation between the estimated second clutch torque capacity and the target drive torque becomes zero. The second clutch torque capacity is feedback controlled. However, since a part of the motor torque is used for cranking, the estimation accuracy of the second clutch torque capacity is lowered. That is, during cranking, the control accuracy of the second clutch torque capacity is lowered, so that the second clutch torque capacity is fluctuated to cause acceleration fluctuations in the vehicle. At time t3, since the motor speed and the engine speed are synchronized, the cranking is finished and the mode is shifted to the HEV mode.

  As described above, in the conventional control, when the second clutch is slipped in, and when the second clutch torque capacity is corrected during cranking, acceleration fluctuation is accompanied. Here, in the travel scene of FIG. 10, the accelerator opening is constant, and the vehicle is constantly traveling at a constant speed. Acceleration fluctuations that occur during steady running are easily noticed by the driver. Moreover, the acceleration fluctuation | variation which arises when a driver | operator's driver | operator has no intention of acceleration is an unexpected thing, and gives a driver uncomfortable feeling.

[Suppression of driver's unexpected acceleration fluctuation]
FIG. 11 is a time chart showing an operation at the time of transition from the EV mode to the HEV mode without the accelerator increase in the first embodiment.
At time t1, since it is determined that there is an engine start request and the responsiveness of engine start is unnecessary, the process shifts to EV slip-in control. In the EV slip-in control, priority is given to smoothness, and the motor torque and the target second clutch torque capacity are gradually changed. For this reason, the level | step difference with target drive torque 2nd clutch torque capacity can be suppressed. Thereby, the acceleration fluctuation | variation at the time of slipping in a 2nd clutch can be suppressed, and the discomfort given to a driver | operator can be reduced. Note that when shifting to EV slip-in control, the time from the engine start request to the slip-in becomes longer, but the driver does not intend to accelerate, so there is no sense of incongruity.

At time t2, since slip-in is detected, the EV slip-in control is shifted to EV slip control. In the EV slip control, the second clutch torque capacity is corrected to coincide with the target drive torque. In the EV slip control, since the motor rotation speed is controlled to be constant and cranking is not performed, the second clutch torque capacity can be accurately estimated from the motor rotation speed and the motor torque. That is, since the control accuracy of the second clutch torque capacity is high, the acceleration fluctuation due to the excessive fluctuation of the second clutch torque capacity does not occur.
At time t3, since the correction of the second clutch torque capacity is completed, the EV slip control is shifted to the cranking control. In the cranking control, the second clutch torque capacity is kept constant. Thereby, since the second clutch torque capacity does not fluctuate during cranking, it is possible to suppress the acceleration fluctuation accompanying the correction of the second clutch torque capacity.
At time t4, since the motor speed and the engine speed are synchronized, the cranking is finished and the mode is shifted to the HEV mode.

Example 1 has the following effects.
(1) When there is a request for starting the engine, a first clutch 8 that connects and disconnects torque transmission between the engine 1 and the motor 2, a second clutch 9 that connects and disconnects torque transmission between the motor 2 and the rear wheel 5, and An integrated controller 21 that slips the second clutch 9 and engages the first clutch 8 to crank the engine 1; and an engine start method switching unit 35 that determines the necessity of engine start responsiveness to the engine start request; The integrated controller 21 corrects the second clutch torque capacity up to the vehicle target drive torque when the slip of the second clutch 9 is detected when it is determined that the responsiveness is unnecessary. Start cranking after completion.
Therefore, since the second clutch torque capacity does not fluctuate during cranking, it is possible to suppress acceleration fluctuations at the time of engine start unexpected by the driver.

(2) When it is determined that the responsiveness is not required, the integrated controller 21 reduces the decrease gradient of the second clutch torque capacity when the second clutch 9 is slipped compared to the case where the responsiveness is determined to be required. To do.
Therefore, the step difference between the target drive torque and the second clutch torque capacity when the second clutch 9 is slipped in can be reduced, and the acceleration fluctuation unexpected by the driver can be suppressed. On the other hand, when it is determined that responsiveness is necessary, the engine start time can be shortened by early slip-in by reducing the second clutch torque capacity earlier.

(3) When it is determined that the responsiveness is necessary, the integrated controller 21 starts cranking as soon as the slip of the second clutch 9 is detected.
Therefore, when it is determined that responsiveness is necessary, the engine start time can be shortened.

(4) The engine start method switching unit 35 determines whether or not responsiveness is necessary based on whether the driver intends to accelerate.
That is, when the driver has an intention to accelerate, priority is given to shortening the engine start time, and when the driver has no intention to accelerate, priority is given to suppression of acceleration fluctuations. As a result, it is possible to achieve both the driving performance corresponding to the driver's acceleration request and the suppression of the driver's unexpected acceleration fluctuation.

(5) The engine start method switching unit 35 determines the necessity of responsiveness based on vehicle parameters (battery SOC, battery voltage, engine water temperature, etc.) that determine whether the engine needs to be started regardless of the driver's intention to accelerate. To do.
That is, when starting the engine for the purpose of system protection, priority is given to shortening the engine starting time if the engine starting delay is not allowed, and priority is given to suppressing acceleration fluctuations if the engine starting delay is allowed. . As a result, it is possible to achieve both avoidance of system failure (for example, battery overdischarge) and suppression of acceleration fluctuations unexpected by the driver. Moreover, early system protection is realizable by using the prefetch value estimated from the present value as a vehicle parameter.

(6) The engine start method switching unit 35 determines the necessity of responsiveness based on the vehicle speed.
Since AT3 has a higher gear ratio in the low vehicle speed range than in the high vehicle speed range, the acceleration fluctuation that occurs when the engine is started becomes larger. Therefore, by giving priority to suppression of acceleration fluctuation in the low vehicle speed range, it is possible to suppress acceleration fluctuation at the time of engine start unexpected by the driver. The same applies to the determination of whether or not the response is possible based on the transmission ratio of AT3 instead of the vehicle speed or in addition to the vehicle speed. When the gear ratio is large, priority is given to suppression of acceleration fluctuations, so that the acceleration fluctuations at the time of engine start unexpected by the driver can be suppressed.

(7) While the vehicle speed control is being performed, the engine start method switching unit 35 determines whether or not responsiveness is necessary based on the target vehicle speed of the vehicle speed control and the deviation between the target vehicle speed and the vehicle speed.
During vehicle speed control by automatic driving, when there is no driver's interrupt request such as a tap operation, acceleration fluctuation at the time of engine start unexpected by the driver can be suppressed by giving priority to acceleration fluctuation wired.

(8) The engine start method switching unit 35 determines the necessity of responsiveness based on the inter-vehicle distance and the vehicle speed during the inter-vehicle distance control.
During inter-vehicle distance control by automatic driving, in a state where the inter-vehicle distance from the preceding vehicle is clogged, priority can be given to suppression of acceleration fluctuations, thereby suppressing acceleration fluctuations at the time of unexpected engine start by the driver.

(9) A second clutch torque capacity correction unit 42 for estimating the second clutch torque capacity is provided, and the integrated controller 21 is in a state where the deviation between the estimated second clutch torque capacity and the target drive torque is equal to or less than a predetermined value. It is determined that the correction is completed when the first predetermined time is continued.
Therefore, it can be accurately determined that the second clutch torque capacity is equivalent to the target drive torque.

[Example 2]
Next, Example 2 will be described. Since the basic configuration is the same as that of the first embodiment, only different points will be described.
[Second clutch torque capacity correction completion determination]
The second clutch torque capacity correction unit 42 determines that the correction of the second clutch torque capacity is completed when the second predetermined time has elapsed from the start of EV slip control, that is, the correction start of the second clutch torque capacity. The second predetermined time is set based on the assumed variation in the second clutch torque capacity and the responsiveness of the control system.
(Cranking control)
In the second embodiment, when it is determined that the responsiveness for starting the engine is not necessary, the timing for raising the engine speed to the motor speed is delayed as compared with the case where it is determined that the responsiveness is necessary. When it is determined that responsiveness is not required, the first clutch torque capacity during cranking is made smaller than when it is determined that responsiveness is required.

[Improved sound vibration performance and reduced battery load]
FIG. 12 is a time chart showing an operation at the time of transition from the EV mode to the HEV mode without the accelerator increase in the second embodiment.
The section from time t1 to t3 is the same as that of the first embodiment shown in FIG. At time t3, since the correction of the second clutch torque capacity is completed, the EV slip control is shifted to the cranking control. In the second embodiment, since the timing for synchronizing the engine speed with the motor speed is delayed, the engine is started in a state where the negative pressure of the engine 1 is developed more than when it is determined that responsiveness is necessary. Thereby, compared with the case of Example 1, the initial explosion torque of the engine 1 can be suppressed. Therefore, a steep change in engine speed can be suppressed, and sound vibration performance can be improved. Also, the first clutch torque capacity during cranking is reduced. Thereby, the peak torque of the motor 2 can be reduced as compared with the case of the first embodiment. Therefore, the load on the battery 17 can be reduced and the durability can be improved. Although the engine start time is extended by the above-described operation, the driver does not feel uncomfortable because the response of the engine start is not required.

The second embodiment has the following effects.
(10) The integrated controller 21 determines that the correction has been completed when the second predetermined time has elapsed since the start of the correction.
Therefore, it can be determined by a simple method that the second clutch torque capacity is equivalent to the target drive torque.

(11) When it is determined that the responsiveness is not required, the integrated controller 21 reduces the engine speed to the motor speed after the negative pressure of the engine 1 is further developed than when the responsiveness is determined to be required. Pull up.
Therefore, the initial explosion torque when starting the engine can be suppressed, and the sound vibration performance can be improved.

(12) When it is determined that responsiveness is not required, the integrated controller 21 makes the first clutch torque capacity during cranking smaller than when it is determined that responsiveness is required.
Therefore, the motor torque at the time of starting the engine can be suppressed, and the instantaneous maximum power of the battery 17 can be reduced. As a result, the load on the battery 17 can be reduced and the durability can be 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.
For example, a motor voltage, an inverter voltage, an engine catalyst temperature, a transmission temperature, an air conditioner state, or the like may be used as a vehicle parameter that determines whether or not to start the engine regardless of the driver's intention to accelerate.

1 engine
2 Motor generator
5 Rear wheel (drive wheel)
8 First clutch
9 Second clutch
21 Integrated controller (engine start control means)
35 Engine start method switching part (responsiveness judging means)
42 Second clutch torque capacity correction unit (second clutch torque capacity estimating means)

Claims (11)

A first clutch for connecting and disconnecting torque transmission between the engine and the motor;
A second clutch for connecting and disconnecting torque transmission between the motor and the drive wheel;
If there is an engine start request, by slipping the second clutch by setting lower than the target second clutch torque capacity corresponding target driving torque of the vehicle is a target value of the torque capacity of the second clutch, the second Engine start control means for engaging the first clutch and cranking the engine when clutch slip is detected ;
Responsiveness determining means for determining the necessity of engine responsiveness to the engine start request;
With
When it is determined that the responsiveness is not required, the engine start control means lowers the target second clutch torque capacity when the second clutch is slipped than when it is determined that the responsiveness is required. with decreasing the gradient, the slip of the second clutch is detected, corrects the torque capacity of the second clutch to the target drive torque equivalent, and wherein the initiating the cranking after the correction completion Control device for hybrid vehicle. In the hybrid vehicle control device according to claim 1,
When it is determined that the responsiveness is necessary, the engine start control unit starts the cranking immediately after detecting the slip of the second clutch. In the hybrid vehicle control device according to claim 1 or 2,
The control device for a hybrid vehicle, wherein the responsiveness determining means determines whether or not the responsiveness is necessary based on whether the driver intends to accelerate. In the hybrid vehicle control device according to any one of claims 1 to 3,
The control device for a hybrid vehicle, wherein the responsiveness determining means determines whether or not the responsiveness is necessary based on a parameter state that determines whether or not to start the engine regardless of a driver's intention to accelerate. In the hybrid vehicle control device according to any one of claims 1 to 4,
The control apparatus for a hybrid vehicle, wherein the responsiveness determining means determines whether or not the responsiveness is necessary based on at least one of a vehicle speed and a gear ratio from the motor to the drive wheel. In the hybrid vehicle control device according to any one of claims 1 to 5,
The response determination unit, when during the performance of the vehicle speed control vehicle speed of the vehicle is automatically driven the vehicle to approach the target vehicle speed, vehicle speed deviation obtained by subtracting the target vehicle speed from the vehicle speed is a positive value the A control apparatus for a hybrid vehicle, which determines that responsiveness is unnecessary and determines that the responsiveness is required when the vehicle speed deviation is a negative value . The hybrid vehicle control device according to any one of claims 1 to 6,
The response determination means, during the implementation of the inter-vehicle distance control vehicle distance between the vehicle and the preceding vehicle is automatically driven the vehicle so as to approach the target following distance, when the inter-vehicle distance is longer than a predetermined following distance A control apparatus for a hybrid vehicle, which determines that the responsiveness is necessary and determines that the responsiveness is unnecessary when the inter-vehicle distance is shorter than the predetermined inter-vehicle distance . In the hybrid vehicle control device according to any one of claims 1 to 7,
A second clutch torque capacity estimation means for estimating the torque capacity of the second clutch,
The engine starting control means, determining that the deviation between the estimated second torque capacity and the target driving torque of the clutch state is below a predetermined value said compensation is completed when the continuous first predetermined time A hybrid vehicle control device. In the hybrid vehicle control device according to any one of claims 1 to 7,
The control apparatus for a hybrid vehicle, wherein the engine start control means determines that the correction is completed when a second predetermined time has elapsed from the start of the correction. In the hybrid vehicle control device according to any one of claims 1 to 9,
When it is determined that the responsiveness is not required, the engine start control means sets the engine speed after the negative pressure of the engine is further developed than when the responsiveness is determined to be required. A control apparatus for a hybrid vehicle, wherein the control apparatus is pulled up to a number. In the hybrid vehicle control device according to any one of claims 1 to 10,
When it is determined that the responsiveness is not required, the engine start control means makes the first clutch torque capacity at the time of cranking smaller than when it is determined that the responsiveness is required. Control device for hybrid vehicle.

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