JP2012153309A - Vehicle start control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle start control device capable of preventing clutch judder upon the start of the vehicle.SOLUTION: In this vehicle start control device shifting a second clutch CL2 interposed between a motor generator MG and right and left rear wheels RL, RR from a slip engagement state to a lockup engagement state upon the start of the vehicle, the shift time from the slip engagement state to the lockup engagement state is shortened when the generation of clutch judder is predicted or detected, as compared with a case where no clutch judder is predicted or detected.

Description

  The present invention relates to a vehicle start control device.

  Patent Document 1 discloses a technology in which a clutch interposed between a motor and a drive wheel is brought into a slip-engaged state when a vehicle starts, and is shifted from a slip-engaged state to a lock-up-fastened state in accordance with an increase in vehicle speed. Has been.

JP2008-323038

If the clutch slip-engaged state continues for a long time, the clutch's μ-V characteristics (characteristics related to the dynamic friction coefficient of the friction material and the relative rotational speed) change due to the temperature rise of the friction material and lubricating oil of the clutch. There is a case where vehicle vibration accompanied by hunting of a slip amount called a clutch judder is generated. When this occurs and continues, it causes factors such as discomfort to the occupant.
An object of the present invention is to provide a vehicle start control device that can suppress clutch judder when the vehicle starts.

  In the present invention, when occurrence of the clutch judder is predicted or detected, the transition time from the slip engagement state to the lockup engagement state is made shorter than when generation of the clutch judder is not predicted or detected.

  Therefore, in the present invention, since the duration of the slip engagement state of the clutch can be shortened, the temperature rise of the friction material and the lubricating oil can be suppressed, and the clutch judder when starting the vehicle can be suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall system diagram showing a rear-wheel drive hybrid vehicle to which a start control device according to a first embodiment is applied. FIG. 3 is a control block diagram of the integrated controller 10 according to the first embodiment. It is a target driving force map. It is a target charge / discharge amount map. It is a mode map. It is the schematic showing the engine operating point setting process in WSC driving mode. It is a map showing the engine target speed in WSC driving mode. FIG. 3 is a control block diagram of an operating point command unit 400 that implements lockup control and judder suppression control according to the first embodiment. 3 is a flowchart illustrating a flow of processing for realizing judder suppression control according to the first exemplary embodiment. 3 is a time chart showing the judder suppressing action of Example 1. FIG. 6 is a control block diagram of an operating point command unit 400 that realizes lockup control and judder suppression control according to a second embodiment. 6 is a time chart showing the judder suppressing action of Example 2. 6 is a time chart showing judder suppression action of Example 3. 12 is a flowchart illustrating a flow of processing for realizing judder suppression control according to a fourth embodiment.

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing the vehicle start control apparatus of this invention is demonstrated based on the Example shown on drawing.
[Example 1]
[Configuration of drive system]
First, the drive system configuration of the hybrid vehicle will be described.
FIG. 1 is an overall system diagram showing a hybrid vehicle by rear wheel drive to which the start control device of Embodiment 1 is applied. As shown in FIG. 1, the drive system of the hybrid vehicle in the first embodiment includes an engine E, a first clutch CL1, a motor generator (motor) MG as a power source, a second clutch CL2, and an automatic transmission AT. 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 E is, for example, a gasoline engine, and the valve opening degree of the throttle valve and the like are controlled based on a control command from the engine controller 1 described later. The engine output shaft is provided with a flywheel FW.
The first clutch CL1 is a clutch interposed between the engine E and the motor generator MG, and the control created by the first clutch hydraulic unit 6 based on a control command from the first clutch controller 5 described later. Actuated by hydraulic pressure, and fastening / release including slip fastening is controlled. Specifically, the first clutch CL1 is a normally closed dry clutch that is completely engaged by the urging force of the leaf spring when not controlled. When a release command for the first clutch CL1 is output, the hydraulic pressure corresponding to the transmission torque capacity command is supplied to the piston to make a stroke, and the transmission torque capacity corresponding to the stroke amount is set. When a stroke exceeding a predetermined value is performed, contact between the clutch plates is cut off and released. Further, in order to reduce friction loss when the clutch is released, the piston is further stroked by a predetermined amount by increasing the hydraulic pressure applied to the piston even after the clutch plate is disconnected.

  On the other hand, when the first clutch CL1 is engaged from the released state, the hydraulic pressure applied to the piston is gradually lowered. Then, the piston starts a stroke, and the clutch plate starts to come into contact when the piston strokes a predetermined amount (corresponding to backlash). Incidentally, whether or not the clutch plate is in contact can be determined by whether or not the engine speed Ne has started increasing. Thereafter, the lower the hydraulic pressure acting on the piston, the higher the transmission torque capacity. In the first embodiment, a normally closed dry clutch is used. However, a normally open type, a wet clutch, a multi-plate or a single plate may be used.

  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 the three-phase AC generated by the inverter 3 is generated based on a control command from a motor controller 2 described later. It is controlled by applying. 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”), or when the rotor is rotated by an external force. Can function as a generator that generates electromotive force at both ends of the stator coil to charge the battery 4 (hereinafter, this operation state is referred to as “regeneration”). The rotor of the motor generator MG is connected to the input shaft of the automatic transmission AT via a damper (not shown).

The second clutch CL2 is a clutch interposed between the motor generator MG and the left and right rear wheels RL, RR, and is generated by the second clutch hydraulic unit 8 based on a control command from the AT controller 7 described later. The fastening / release including slip fastening is controlled by the control hydraulic pressure.
The automatic transmission AT is a transmission that automatically switches the stepped gear ratio such as forward 5 speed, reverse 1 speed, etc. according to the vehicle speed VSP, accelerator opening APO, etc., and the second clutch CL2 is a new dedicated clutch In addition to the above, some of the frictional engagement elements among the plurality of frictional engagement elements that are engaged at each gear stage of the automatic transmission AT are used.
The output shaft of the automatic transmission AT is connected 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 as vehicle drive shafts. The first clutch CL1 and the second clutch CL2 are, for example, wet multi-plate clutches that can continuously control the oil flow rate and hydraulic pressure with a proportional solenoid.

This hybrid drive system has three travel modes according to the engaged / released state of the first clutch CL1.
The first travel mode is an electric vehicle travel mode (hereinafter abbreviated as “EV travel mode”) as a motor use travel mode that travels using only the power of the motor generator MG as a power source with the first clutch CL1 opened. It is.
The second travel mode is an engine use travel mode (hereinafter, abbreviated as “HEV travel mode”) in which the first clutch CL1 is engaged and the engine E is included in the power source.
In the third travel mode, the second clutch CL2 is slip-controlled while the first clutch CL1 is engaged, and the engine travel slip travel mode (hereinafter referred to as “WSC travel mode”) is performed while the engine E is included in the power source. ). This mode is a mode in which creep running can be achieved particularly when the battery SOC is low or the engine water temperature is low. When transitioning from the EV travel mode to the HEV travel mode, the first clutch CL1 is engaged and the engine is started using the torque of the motor generator MG.

The “HEV travel mode” has three travel modes of “engine travel mode”, “motor assist travel mode”, and “travel power generation mode”.
In the “engine running mode”, the left and right rear wheels RL and RR are moved using only the engine E as a power source. In the “motor-assisted travel mode”, the left and right rear wheels RL and RR are moved using the engine E and the motor generator MG as power sources. In the “running power generation mode”, the left and right rear wheels RL and RR are moved using the engine E as a power source, and the motor generator MG functions as a generator.
During constant speed operation or acceleration operation, motor generator MG is operated as a generator using the power of engine E. Further, during deceleration operation, braking energy is regenerated and electric power is generated by the motor generator MG and used for charging the battery 4.
Further, as a further mode, there is a power generation mode in which the motor generator MG is operated as a generator using the power of the engine E when the vehicle is stopped.

[Control system configuration]
Next, the control system of the hybrid vehicle will be described.
As shown in FIG. 1, the control system of the 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. The AT controller 7, the second clutch hydraulic unit 8, the brake controller 9, and the integrated controller 10 are configured. 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 an information exchangeable CAN communication line 11. .
The engine controller 1 inputs the engine speed information from the engine speed sensor 12, and controls the engine operating point (Ne: engine speed, Te: engine torque) according to the target engine torque command from the integrated controller 10, etc. For example, to a throttle valve actuator (not shown). Information such as the engine speed Ne is supplied to the integrated controller 10 via the CAN communication line 11.

The motor controller 2 inputs information from the resolver 13 that detects the rotor rotational position of the motor generator MG, and according to a target motor generator torque command from the integrated controller 10, the motor operating point (Nm: motor generator) of the motor generator MG A command for controlling the rotation speed (Tm: motor generator torque) is output to the inverter 3. The motor controller 2 monitors the battery SOC indicating the state of charge of the battery 4, and the battery SOC information is used as control information for the motor generator MG and is supplied to the integrated controller 10 via the CAN communication line 11. Is done.
The first clutch controller 5 inputs sensor information from the first clutch hydraulic pressure sensor 14 and the first clutch stroke sensor 15, and engages / disengages the first clutch CL1 according to the first clutch control command from the integrated controller 10. A control command is output to the first clutch hydraulic unit 6. The information on the first clutch stroke C1S is supplied to the integrated controller 10 via the CAN communication line 11.

The AT controller 7 inputs information of each sensor from an accelerator switch 16, a vehicle speed sensor 17, a second clutch hydraulic pressure sensor 18, and an inhibitor switch that outputs a signal corresponding to the position of the shift lever operated by the driver. In response to the second clutch control command from 10, a command for controlling engagement / disengagement of the second clutch CL2 is output to the second clutch hydraulic unit 8 in the AT hydraulic control valve. Information on the accelerator opening APO, the vehicle speed VSP, and the inhibitor switch is supplied to the integrated controller 10 via the CAN communication line 11.
The brake controller 9 inputs the sensor information from the wheel speed sensor 19 for detecting each wheel speed of the four wheels and the brake stroke sensor 20, and regenerates the required braking force obtained from the brake stroke BS when the brake is depressed, for example. When the braking force alone is insufficient, the regenerative cooperative brake control is performed based on the regenerative cooperative control command from the integrated controller 10 so that the shortage is supplemented by the mechanical braking force (braking force by the friction brake).

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 integrated controller 10 detects the motor rotation speed Nm, and the second clutch output rotation speed N2out. A second clutch output speed sensor (clutch output speed detection means) 22 for detecting the second clutch torque, a second clutch torque sensor 23 for detecting a second clutch transmission torque capacity TCL2 (second clutch torque), and a brake hydraulic pressure sensor 24 A second clutch temperature sensor (clutch temperature detecting means) 10a for detecting the temperature of the second clutch CL2, a G sensor 10b for detecting longitudinal acceleration, a motor temperature sensor 10c for detecting the temperature of the motor generator MG, and a battery 4 Each sensor information from the battery temperature sensor 10d for detecting the temperature of the sensor and information obtained via the CAN communication line 11 are input.
The integrated controller 10 also controls the operation of the engine E according to the control command to the engine controller 1, the operation control of the motor generator MG according to the control command to the motor controller 2, and the first control command to the first clutch controller 5. Engagement / release control of the clutch CL1 and engagement / release control of the second clutch CL2 by a control command to the AT controller 7 are performed.

FIG. 2 is a control block diagram of the integrated controller 10 according to the first embodiment. The integrated controller 10 includes a target driving force calculation unit 100, a mode selection unit 200, a target charge / discharge calculation unit 300, and an operating point command unit 400. And a shift control unit 500.
The target driving force calculation unit 100 calculates a target driving force tFoO from the accelerator opening APO and the vehicle speed VSP using the target driving force map shown in FIG.
The mode selection unit 200 selects a target mode based on the mode map. FIG. 5 shows a mode map. The mode map has an EV travel mode, a WSC travel mode, and an HEV travel mode, and calculates the target mode from the accelerator opening APO and the vehicle speed VSP. However, even if the EV travel mode is selected, if the battery SOC is equal to or lower than the predetermined value, the “HEV travel mode” or the “WSC travel mode” is forcibly set as the target mode.

The target charge / discharge calculation unit 300 calculates the target charge / discharge power tP from the battery SOC using the target charge / discharge amount map shown in FIG. In the target charge / discharge amount map, the EVON line for permitting or prohibiting the EV travel mode is set to SOC = 50%, and the EVOFF line is set to SOC = 35%.
When SOC ≧ 50%, the EV drive mode area appears in the mode map of FIG. Once the EV driving mode area appears in the mode map, this area continues to appear until the SOC drops below 35%.
When SOC <35%, the EV drive mode area disappears in the mode map of FIG. When the EV drive mode area disappears from within the mode map, this area continues to disappear until the SOC reaches 50%.

In the operating point command unit 400, from the accelerator opening APO, the target driving force tFoO, the target mode, the vehicle speed VSP, and the target charging / discharging power tP, the transient target engine torque A target motor generator torque, a target second clutch transmission torque capacity, a target gear position of the automatic transmission AT, and a first clutch solenoid current command which is a transmission torque capacity command of the first clutch CL1 are calculated.
The shift control unit 500 drives and controls the solenoid valve in the automatic transmission AT so as to achieve the target second clutch transmission torque capacity and the target shift speed according to the shift schedule shown in the shift map. The shift map is a map in which a target gear position is set in advance based on the vehicle speed VSP and the accelerator opening APO.

[About WSC driving mode]
Next, details of the WSC travel mode will be described.
The WSC travel mode is characterized in that the engine E is maintained in an operating state, and has high responsiveness to a target driving force change. Specifically, the first clutch CL1 is fully engaged, the second clutch CL2 is slip-controlled as a transmission torque capacity corresponding to the target driving force, and the vehicle travels using one of the engine E and the motor generator MG.
Since the hybrid vehicle of the first embodiment does not have an element that absorbs the rotational speed difference like the torque converter, when both the first clutch CL1 and the second clutch CL2 are completely engaged, the vehicle speed depends on the rotational speed of the engine E. Will be decided. The engine E has a lower limit value based on the idling engine speed for maintaining the self-sustaining rotation. The idling engine speed is further increased when the engine is idling up due to warm-up operation of the engine or the like. In addition, when the target driving force is high, it may not be possible to quickly transition to the HEV traveling mode.

On the other hand, in the EV travel mode, since the first clutch CL1 is released, there is no limit associated with the lower limit value due to the engine speed. However, in cases where it is difficult to travel in the EV travel mode due to restrictions based on the battery SOC, or in a region where the accelerator opening APO is large and the target driving force cannot be achieved only by the motor generator MG, a stable torque is generated by the engine E. There is no means.
Therefore, when the vehicle speed is lower than the vehicle speed corresponding to the lower limit value and it is difficult to travel in the EV travel mode, or when the motor generator MG alone cannot achieve the target driving force, the engine speed Ne is set to a predetermined value. The second clutch CL2 is controlled to slip, and the WSC travel mode for traveling using the engine torque Te is selected.

FIG. 6 is a schematic diagram showing the engine operating point setting process in the WSC running mode, and FIG. 7 is a map showing the engine target speed in the WSC running mode.
When the driver operates the accelerator pedal in the WSC travel mode, the target engine speed characteristic corresponding to the accelerator opening APO is selected based on FIG. 7, and the target engine speed corresponding to the vehicle speed VSP is set based on this characteristic. Is done. Then, the target engine torque corresponding to the target engine speed is calculated by the engine operating point setting process shown in FIG.
Here, the operating point of the engine E is defined as a point defined by the engine speed Ne and the engine torque Te. As shown in FIG. 6, it is desirable that the engine operating point is operated on a line (hereinafter referred to as “α line”) connecting operating points with high output efficiency of engine E.
However, when the engine speed Ne is set as described above, an operating point away from the α line is selected depending on the driver's accelerator pedal operation amount. Therefore, in order to bring the engine operating point closer to the α line, the target engine torque is feedforward controlled to a value that takes the α line into consideration.

On the other hand, the motor generator MG executes the rotational speed feedback control using the set engine rotational speed as the target rotational speed. Since the engine E and the motor generator MG are now in a direct connection state, the motor generator MG is controlled so as to maintain the target rotational speed, and the rotational speed of the engine E is also automatically feedback-controlled. It becomes.
At this time, the torque output from motor generator MG is automatically controlled so as to fill in the deviation between the target engine torque and the target driving force determined in consideration of the α ray. In motor generator MG, a basic torque control amount (regeneration / power running) is given so as to fill the deviation, and feedback control is performed so as to coincide with the target engine speed.

When the target driving force is smaller than the driving force on the α line at a certain engine speed, the engine output efficiency increases as the engine output torque is increased. At this time, the motor generator MG recovers the energy corresponding to the increased output, so that efficient power generation is possible while the torque itself input to the second clutch CL2 is set to the torque required by the driver.
However, since the upper limit of torque that can be generated is determined according to the state of the battery SOC, the required power generation output (SOC required power generation power) from the battery SOC and the deviation between the torque at the current operating point and the torque on the α line (α It is necessary to consider the magnitude relationship with the (line generated power).

FIG. 6A is a schematic diagram when the α-ray generated power is larger than the SOC required generated power. Since the engine output torque cannot be increased above the SOC required power generation, the operating point cannot be moved on the α line. However, fuel efficiency is improved by moving to a more efficient point.
FIG. 6B is a schematic diagram when the α-ray generated power is smaller than the SOC required generated power. Since the engine operating point can be moved on the α line within the SOC required power generation range, in this case, it is possible to generate power while maintaining the operating point with the highest fuel efficiency.
FIG. 6C is a schematic diagram when the engine operating point is higher than the α line. When the operating point corresponding to the target driving force is higher than the α line, the engine torque Te is reduced on the condition that the battery SOC has a margin, and the shortage is compensated by the power running of the motor generator MG. Thereby, the target driving force can be achieved while improving the fuel efficiency.

[When starting in WSC mode]
Next, the start time in the WSC travel mode will be described.
When starting from WSC drive mode, lock-up control is performed to gradually reduce the slip amount of the second clutch CL2 as the vehicle speed increases and shift from the slip-engaged state to the lock-up engaged state (fully engaged state). To do.
Here, if the slip engagement state of the second clutch CL2 continues for a long time due to the continuation of the WSC driving mode including the above-described lock-up control, μ− due to the temperature rise of the friction material and the lubricating oil of the second clutch CL2. The V characteristic (the relational characteristic between the dynamic friction coefficient characteristic of the friction material and the relative rotational speed) changes, and there is a case where a vehicle vibration accompanying a hunting of a slip amount called a clutch judder occurs.

  Therefore, in the first embodiment, when the temperature of the second clutch CL2 detected by the second clutch temperature sensor 10a is equal to or higher than a predetermined temperature, the aim is to suppress the generation of clutch judder when starting from the WSC traveling mode. Predicts that clutch judder will occur and causes the second clutch CL2 to shift to the lock-up engagement state earlier than when the temperature of the second clutch CL2 is lower than a predetermined temperature (referred to as normal control). Implement suppression control.

FIG. 8 is a control block diagram of an operating point command unit (judder suppression control means) 400 for realizing the lockup control and judder suppression control.
The target slip rotation speed setting unit 401 sets the target slip rotation speed of the second clutch CL2 for normal control. The target slip rotation speed for normal control is set so as to decrease as the vehicle speed VSP increases. For example, the target slip rotation speed is decreased at a constant change rate with respect to the increase in the vehicle speed VSP.
The adder 402 adds the target slip rotational speed for normal control and the second clutch output rotational speed N2out detected by the second clutch output rotational speed sensor 22 to add the target input rotational speed for normal control (motor generator MG). Output the target rotation speed).

  The target slip rotation speed setting unit 403 sets the target slip rotation speed of the second clutch CL2 for judder suppression control. The target slip rotation speed for judder suppression control is set to be lower as the vehicle speed VSP is higher, similar to the target slip rotation speed for normal control, but at the same vehicle speed as the target slip rotation speed for normal control. The target slip rotational speed is set to a smaller value. Further, the target slip rotation speed is set in consideration of the deterioration degree of the second clutch CL2, the temperature history, and the like.

The adder 404 adds the second clutch output rotational speed N2out detected by the second clutch output rotational speed sensor 22 and the target slip rotational speed for judder suppression control, and outputs the target input rotational speed for judder suppression control. To do.
The switch 405 outputs the target input rotation speed for normal control as the target input rotation speed when the judder suppression control permission condition described later is not satisfied, and when the judder suppression control permission condition is satisfied, the judder suppression control is performed. The target input rotation speed is output as the target input rotation speed. That is, during normal control, the target input rotational speed for normal control is set as the target rotational speed of motor generator MG, and during judder suppression control, the target rotational speed for judder suppression control is set as the target rotational speed of motor generator MG.

FIG. 9 is a flowchart illustrating a flow of processing for realizing judder suppression control according to the first embodiment. Each step will be described below. The following processing is repeatedly executed at a predetermined calculation cycle from the start to the end of the lockup control.
In step S1, it is determined whether the temperature of the second clutch CL2 is equal to or higher than a predetermined temperature. If YES, the process proceeds to step S2, and if NO, the process proceeds to return. Here, the predetermined temperature is a temperature at which it can be predicted that clutch judder will occur in the second clutch CL2. Step S1 corresponds to judder determination means for predicting the occurrence of clutch judder.
In step S2, it is determined whether or not the accelerator opening APO is equal to or smaller than a predetermined opening. If YES, the process proceeds to step S3, and if NO, the process proceeds to return. Here, the predetermined opening is an accelerator opening at which the shock generated in the drive system when the second clutch CL2 is in the lockup engagement state is suppressed to a level that does not give the driver a sense of incongruity. That is, when the accelerator opening APO is larger than the predetermined opening, the judder suppression control is disallowed, so that it is possible to prevent the driver from feeling a sense of incongruity by generating a large shock in the vehicle.

In step S3, it is determined whether or not the vehicle speed VSP is equal to or higher than a predetermined vehicle speed. If YES, the process proceeds to step S4, and if NO, the process proceeds to return. Here, the predetermined vehicle speed is a speed at which it can be predicted that no engine stall will occur when the second clutch CL2 is in the lock-up engaged state. In other words, when the vehicle speed VSP is less than the predetermined vehicle speed, the occurrence of engine stall can be suppressed by disabling judder suppression control.
It is assumed that the judder suppression control permission condition is satisfied when it is determined YES in all of steps S1 to S3.
In step S4, judder suppression control is started, and the process proceeds to step S5. In this step, the target rotational speed of the motor generator MG is switched from normal control to judder suppression control.
In step S5, it is determined whether or not the lockup control has ended, that is, whether or not the second clutch CL2 is in the lockup engagement state. If YES, this control is ended and the HEV traveling mode is set. The process proceeds to control. If NO, the process proceeds to step S6.

In step S6, it is determined whether or not the vehicle speed VSP is equal to or higher than a value obtained by removing the hysteresis value from the predetermined vehicle speed. If YES, the process proceeds to step S4, and if NO, the process proceeds to step S7. The predetermined vehicle speed is the same value as the predetermined vehicle speed in step S3. The processing in this step is for preventing hunting between normal control and judder suppression control when the temperature of the second clutch CL2 is near a predetermined temperature.
In step S7, the judder suppression control is terminated and the process proceeds to return. In this step, the target rotational speed of the motor generator MG is returned from the judder suppression control to the normal control.

Next, the operation will be described.
[Judder suppression action]
FIG. 10 is a time chart showing the judder suppression effect of the first embodiment. At a time point before the time point t1, the accelerator opening degree APO is not more than the predetermined opening degree, but the temperature of the second clutch CL2 is less than the predetermined temperature. And since the vehicle speed VSP is less than the predetermined vehicle speed, the judder suppression control permission condition is not satisfied. Therefore, the target slip rotation speed becomes the target slip rotation speed for normal control.
At time t1, since the temperature of the second clutch CL2 reaches a predetermined temperature and the vehicle speed VSP becomes equal to or higher than the predetermined vehicle speed, the judder suppression control permission condition is satisfied, and the process proceeds to judder suppression control. In judder suppression control, the target rotational speed of motor generator MG is switched from normal control to judder suppression control, so the target slip rotational speed becomes the target slip rotational speed for judder suppression control.

During the period from time t1 to t2, the target slip rotation speed decreases with a larger gradient than during normal control, so the difference between the input rotation speed and the output rotation speed of the second clutch CL2, that is, the slip of the second clutch CL2 The amount is small compared to that during normal control.
At time t2, since the target slip rotational speed has become equal to or less than the predetermined rotational speed, the WSC traveling mode is changed to the HEV traveling mode, the control method of the motor generator MG is switched from the rotational speed control to the torque control, and the second clutch CL2 The target clutch hydraulic pressure (hydraulic pressure for obtaining the target second clutch transmission torque capacity) starts to rise from the value corresponding to the target driving force toward the lockup hydraulic pressure (hydraulic pressure in the lockup engagement state).
At time t3, the slip rotation speed of the second clutch CL2 converges to zero.

Here, even if the temperature of the second clutch CL2 reaches a predetermined temperature, if the judder suppression control is not performed and the normal control is continued, the target slip rotation speed becomes equal to or less than the predetermined rotation speed at time t4, and at time t5 The slip rotation speed of the 2-clutch CL2 becomes zero. That is, until the time point t5, the slip amount of the second clutch CL2 does not converge to zero, and the slip engagement state continues, so that the possibility of occurrence of clutch judder increases due to temperature rise.
In contrast, in the first embodiment, the judder suppression control is performed when the temperature of the second clutch CL2 is equal to or higher than the predetermined temperature, so that the slip rotation speed of the second clutch CL2 is converged to zero at an earlier time point. be able to. That is, since the duration of the slip engagement state of the second clutch CL2 can be shortened, the temperature rise of the friction material and the lubricating oil can be suppressed, and the clutch judder when starting the vehicle can be suppressed.

  In the first embodiment, occurrence of clutch judder is predicted based on the temperature of the second clutch CL2, and judder suppression control is performed when occurrence of the clutch judder is predicted. The clutch judder is generated by the change in the μ-V characteristic of the second clutch CL2, and the change in the μ-V characteristic is caused by the temperature rise of the friction material and the lubricating oil of the second clutch CL2. The occurrence of clutch judder can be predicted by monitoring the temperature. Therefore, by predicting the occurrence of clutch judder based on the temperature of the second clutch CL2, and executing the judder suppression control when the occurrence of the clutch judder is predicted, it is possible to prevent the occurrence of clutch judder in advance. Can be increased.

Next, the effect will be described.
The vehicle start control device according to the first embodiment has the following effects.
(1) In a vehicle start control device for shifting a second clutch CL2 interposed between a motor generator MG and left and right rear wheels RL, RR from a slip engagement state to a lockup engagement state when the vehicle starts Judder determination means (step S1) that predicts the occurrence of judder and judder suppression control that shortens the transition time from the slip engagement state to the lockup engagement state when the occurrence of clutch judder is predicted, compared to when it is not predicted And an operating point command unit 400 for executing
Thereby, since the duration of the slip engagement state of the second clutch CL2 can be shortened, the temperature increase of the friction material and the lubricating oil can be suppressed, the clutch judder at the start of the vehicle can be suppressed, and the robustness of drivability can be ensured.

  (2) During the judder suppression control, the operating point command unit 400 shortens the time for the slip rotation speed of the second clutch CL2 to converge to zero compared to the normal control, so that the duration of the slip engagement state of the second clutch CL2 Can be shortened.

  (3) A second clutch temperature sensor 10a for detecting the temperature of the second clutch CL2 is provided, and the judder judging means is a clutch judder for predicting the occurrence of judder when the temperature of the second clutch CL2 is equal to or higher than a predetermined temperature. It is possible to increase the possibility of preventing the occurrence of this.

[Example 2]
The second embodiment is different from the first embodiment only in a configuration that realizes lockup control and judder suppression control. The illustration and description of the configuration common to the first embodiment is omitted.
FIG. 11 is a control block diagram of the operating point command unit 400 that realizes the lock-up control and the judder suppression control of the second embodiment.
The safety factor multiplier 411 outputs the lockup hydraulic pressure obtained by multiplying the estimated input torque of the second clutch CL2 (the estimated output torque of the motor generator MG) by a predetermined safety factor.

The slip amount large table 412 refers to a table of a hydraulic gradient [KPa / sec] with respect to a preset estimated input torque, and outputs a hydraulic gradient according to the estimated input torque. This table has characteristics that become steeper as the estimated input torque increases.
The small slip amount table 413 refers to a hydraulic gradient table with respect to a preset estimated input torque, and outputs a hydraulic gradient according to the estimated input torque. This table has a characteristic that becomes steeper as the estimated input torque increases, and has a gentler slope than the slip amount large table 412.

The switch 414 inputs the slip rotation speed of the second clutch CL2 as a condition, and when the slip rotation speed is equal to or higher than a predetermined rotation speed, outputs the output of the slip amount large table 412 as a hydraulic gradient for normal control. When the rotational speed is less than the predetermined rotational speed, the output of the slip amount small table 413 is output as a hydraulic gradient for normal control.
The judder table 415 refers to a preset hydraulic gradient table with respect to the temperature of the second clutch CL2, and outputs a hydraulic gradient according to the estimated input torque. This table has a characteristic that becomes steeper as the temperature of the second clutch CL2 becomes higher. Further, the hydraulic pressure gradient is set in consideration of the degree of deterioration of the second clutch CL2, the temperature history, and the like.

The switch 416 outputs the output of the switch 414 as a hydraulic gradient for normal control when the judder suppression control permission condition is not satisfied, and outputs the judder table 415 when the judder suppression control permission condition is satisfied. Is output as a hydraulic gradient for judder suppression control.
The lockup transition target clutch hydraulic pressure calculation unit 417 outputs the hydraulic pressure of the second clutch CL2 from the switcher 416 from the control start hydraulic pressure (the hydraulic pressure of the second clutch CL2 at the start of WSC control) to the lockup hydraulic pressure. The target clutch hydraulic pressure that changes with the hydraulic gradient is calculated. That is, the target clutch hydraulic pressure is calculated based on the hydraulic gradient for normal control during normal control, and the target clutch hydraulic pressure is calculated based on the hydraulic gradient for judder suppression control during judder suppression control.

  The flow of processing for realizing the judder suppression control of the second embodiment is the same as the flowchart shown in FIG. 9, but in the second embodiment, the target clutch hydraulic pressure is changed from that for normal control at the start of the judder suppression control in step S5. Switching to judder suppression control, and at the end of judder suppression control in step S7, the target clutch hydraulic pressure is switched from judder suppression control to normal control.

Next, the operation will be described.
[Judder suppression action]
FIG. 12 is a time chart showing the judder suppressing action of the second embodiment. The time point before the time point t1 is the same as the time chart shown in FIG.
At time t1, since the temperature of the second clutch CL2 reaches a predetermined temperature and the vehicle speed VSP becomes equal to or higher than the predetermined vehicle speed, the judder suppression control permission condition is satisfied, and the process proceeds to judder suppression control. In judder suppression control, the target clutch hydraulic pressure of the second clutch CL2 is switched from normal control to judder suppression control.
During the period from time t1 to t2, the target clutch hydraulic pressure rises with a larger gradient than during normal control, so the difference between the input rotational speed and the output rotational speed of the second clutch CL2, that is, the slip amount of the second clutch CL2 is Less compared to normal control.
At time t2, the slip amount of the second clutch CL2 converges to zero, and at time t3, the target clutch hydraulic pressure reaches the lockup hydraulic pressure.

Here, even if the temperature of the second clutch CL2 reaches a predetermined temperature, if the normal control is continued without executing the judder suppression control, it is obtained with reference to the slip amount large table 412 or the slip amount small table 413. Since the target clutch hydraulic pressure is set according to the hydraulic gradient, the slip amount does not converge to zero until time t4. In other words, the slip engagement state of the second clutch CL2 continues until the time point t4, so that the possibility of occurrence of clutch judder increases due to the temperature rise.
On the other hand, in the second embodiment, the judder suppression control is performed when the temperature of the second clutch CL2 becomes equal to or higher than the predetermined temperature, so that the hydraulic pressure of the second clutch CL2 is increased to the lockup hydraulic pressure earlier. Can do. That is, since the duration of the slip engagement state of the second clutch CL2 can be shortened, the temperature rise of the friction material and the lubricating oil can be suppressed, and the clutch judder when starting the vehicle can be suppressed.

Next, the effect will be described.
The vehicle start control device according to the second embodiment has the following effects in addition to the effects (1) and (3) of the first embodiment.
(4) Since the operating point command unit 400 increases the increase gradient of the transmission torque capacity of the second clutch CL2 during judder suppression control, the duration of the slip engagement state of the second clutch CL2 can be shortened.

Example 3
The third embodiment is different from the first embodiment only in a configuration that realizes lockup control and judder suppression control. The illustration and description of the configuration common to the first embodiment is omitted.
In the third embodiment, when the temperature of the second clutch CL2 becomes equal to or higher than a predetermined value, the target motor generator torque is reduced below the value that fills the deviation between the target engine torque and the target driving force, and the input torque of the second clutch CL2 is reached. Suppress. At this time, the amount of decrease in the input torque is increased as the temperature of the second clutch CL2 is higher. The time for reducing the input torque may be a fixed time or until the slip amount of the second clutch CL2 becomes a predetermined amount or less.

  The flow of processing for realizing the judder suppression control of the third embodiment is the same as the flowchart shown in FIG. 9, but in the third embodiment, the input torque is reduced at the start of the judder suppression control in step S5, and step S7 is performed. At the end of the judder suppression control, the input torque is restored.

Next, the operation will be described.
[Judder suppression action]
FIG. 13 is a time chart showing the judder suppressing action of the third embodiment, and the time point before the time point t1 is the same as the time chart shown in FIG.
At time t1, since the temperature of the second clutch CL2 reaches a predetermined temperature and the vehicle speed VSP becomes equal to or higher than the predetermined vehicle speed, the judder suppression control permission condition is satisfied, and the process proceeds to judder suppression control. In the judder suppression control, the target motor generator torque is reduced according to the temperature of the second clutch CL2.

In the period from time t1 to t2, the input torque decreases as the target motor generator torque decreases. Therefore, the difference between the input rotation speed and the output rotation speed of the second clutch CL2, that is, the slip amount of the second clutch CL2. Is less than in normal control.
At time t2, the target motor generator torque is returned because a certain time has elapsed from time t1 or the slip amount of the second clutch CL2 has become equal to or less than a predetermined amount. Further, the target clutch hydraulic pressure of the second clutch CL2 starts to rise from the value corresponding to the target driving force toward the lockup hydraulic pressure.
At time t3, the slip rotation speed of the second clutch CL2 converges to zero.

Here, even if the temperature of the second clutch CL2 reaches a predetermined temperature, the judder suppression control is not performed, and if normal control is continued, the input torque of the second clutch CL2 is constant, so the slip amount until time t4. Does not converge to zero. In other words, the slip engagement state of the second clutch CL2 continues until the time point t4, so that the possibility of occurrence of clutch judder increases due to the temperature rise.
In contrast, in the third embodiment, when the temperature of the second clutch CL2 becomes equal to or higher than the predetermined temperature, the slip amount of the second clutch CL2 is suppressed and the slip amount is reduced at an earlier time by performing the judder suppression control. Can converge to zero. That is, since the duration of the slip engagement state of the second clutch CL2 can be shortened, the temperature rise of the friction material and the lubricating oil can be suppressed, and the clutch judder when starting the vehicle can be suppressed.

Next, the effect will be described.
The vehicle start control device according to the third embodiment has the following effects in addition to the effects (1) and (3) of the first embodiment.
(5) Since the operating point command unit 400 reduces the input torque of the second clutch CL2 during judder suppression control, the duration of the slip engagement state of the second clutch CL2 can be shortened.

Example 4
The fourth embodiment is different from the first embodiment only in the judder suppression control permission condition. The illustration and description of the configuration common to the first embodiment is omitted.
FIG. 14 is a flowchart showing a flow of processing for realizing judder suppression control according to the fourth embodiment. Each step will be described below. Note that steps that perform the same processing as in the flowchart shown in FIG. 9 are denoted by the same step numbers and description thereof is omitted.
In step S11, it is determined whether judder has occurred. If YES, the process proceeds to step S4, and if NO, the process proceeds to return. Here, the second clutch output rotational speed N2out detected by the second clutch output rotational speed sensor 22 is read, and judder occurs when the second clutch output rotational speed N2out fluctuates with respect to the motor generator rotational speed Nm. It is determined that Step S11 corresponds to judder determination means for detecting the occurrence of judder.

Next, the operation will be described.
[Judder suppression action]
In the fourth embodiment, the occurrence of clutch judder is detected by the fluctuation in the second clutch output rotational speed N2out, and judder suppression control is performed when the occurrence of the clutch judder is detected. When clutch judder occurs, the second clutch output speed N2out changes with respect to the motor generator speed Nm due to slip hunting. Therefore, the occurrence of clutch judder is detected by monitoring the second clutch output speed N2out. it can. Therefore, the occurrence of clutch judder is detected from the fluctuation of the second clutch output rotational speed N2out, and when the occurrence of the clutch judder is detected, the judder suppression control is immediately performed to suppress the clutch judder from continuing. It can reduce the uncomfortable feeling given to the driver.

Next, the effect will be described.
The vehicle start control device according to the fourth embodiment has the following effects in addition to the effects (1) and (2) of the first embodiment.
(6) The second clutch output rotational speed sensor 22 for detecting the second clutch output rotational speed N2out is provided, and the judder determination means (S11) generates judder when the second clutch output rotational speed N2out is fluctuating. Therefore, it is possible to reduce discomfort given to the driver by suppressing the clutch judder from continuing.

(Other examples)
As described above, the vehicle start control device according to the present invention has been described based on each embodiment. However, the present invention is not limited to the above-described configuration, and other configurations can be adopted without departing from the scope of the present invention. For example, although an FR type hybrid vehicle has been described, an FF type hybrid vehicle may be used.
In the embodiment, the example in which the temperature of the second clutch CL2 is actually measured using the second clutch temperature sensor 10a has been shown, but the temperature may be estimated based on the slip rotational speed or the like.
In the fourth embodiment, the judder suppression control of the second or third embodiment may be executed instead of the judder suppression control of the first embodiment.

10a Clutch temperature sensor (clutch temperature detection means)
22 Clutch output speed sensor (Clutch output speed detector)
400 Operating point command section (judder suppression control means)
CL2 Second clutch (clutch)
E engine (power source)
MG motor generator
RL Left rear wheel (drive wheel)
RR Right rear wheel (drive wheel)
S1 Judder judgment means
S11 Judder judgment means

Claims (6)

In a vehicle start control device that shifts a clutch interposed between a power source and a drive wheel from a slip engagement state to a lock-up engagement state when the vehicle starts,
Judder determination means for predicting or detecting the occurrence of clutch judder;
A judder suppression control means for executing judder suppression control for shortening a transition time from the slip engagement state to the lockup engagement state when the occurrence of the clutch judder is predicted or detected, compared to a case where the occurrence of the clutch judder is not predicted or detected; ,
A vehicle start control device comprising: In the vehicle start control device according to claim 1,
The vehicle start control device characterized in that the judder suppression control means shortens the convergence time of the slip rotational speed of the clutch during the judder suppression control. In the vehicle start control device according to claim 1,
The vehicle start control device characterized in that the judder suppression control means increases an increasing gradient of the transmission torque capacity of the clutch during the judder suppression control. In the vehicle start control device according to claim 1,
The vehicle start control device, wherein the judder suppression control means reduces an input torque of the clutch during the judder suppression control. The vehicle start control device according to any one of claims 1 to 4,
Clutch temperature detecting means for detecting the temperature of the clutch;
The vehicle start control device, wherein the judder determination means predicts the occurrence of the judder when a temperature of the clutch is equal to or higher than a predetermined temperature. The vehicle start control device according to any one of claims 1 to 4,
Clutch output rotation speed detecting means for detecting the output rotation speed of the clutch;
The vehicle start control device, wherein the judder determination means determines that the judder is generated when the output rotational speed of the clutch is fluctuating.

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