JP4935268B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control device including a fastening element between a motor and a drive wheel.

The technique of patent document 1 is disclosed as a hybrid vehicle. This publication includes an engine clutch that connects and disconnects the engine and the motor, and an output clutch that connects and disconnects the motor and the drive wheel, and controls the engagement torque of the output clutch so that the input side rotational speed of the output clutch is substantially constant. is doing.
JP 2001-263383 A

  In the configuration described in Patent Document 1, when the slip control of the output clutch is performed, the fastening torque is controlled so that the input side rotational speed is constant. However, due to this fluctuation, the fastening torque of the output clutch also fluctuates, which may cause the driver to feel uncomfortable.

  The present invention has been made paying attention to the above problem, and is a vehicle control device that can be fastened without giving a driver a sense of incongruity even when a fastening element between a motor and a drive wheel is fastened during traveling. The purpose is to provide.

In order to achieve the above object, in the present invention, a target fastening torque is calculated based on a first fastening element interposed between a power source and a drive wheel, and a required driving force, and the first fastening element is fastened. From the fastening torque control means for controlling the torque to be the target fastening torque, the torque control means for controlling the torque of the power source to be the target torque, and the rotational speed on the drive wheel side of the first fastening element And a rotational speed control means for controlling the rotational speed of the power source so as to increase the rotational speed on the power source side, and a fastening torque estimation for estimating the fastening torque of the first fastening element based on the torque of the power source. And the fastening torque estimated when the fastening torque of the first fastening element is controlled by the fastening torque control means and the rotational speed of the power source is controlled by the rotational speed control means. The target tightening When the difference between the binding torque is below a predetermined value, characterized in that and a switching means for switching to the torque control means from the rotational speed control means.

  Therefore, in the vehicle control apparatus of the present invention, the actual fastening torque of the first fastening element can be accurately estimated from the torque of the power source, and fluctuations in output torque to the drive wheels can be suppressed. .

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

  First, the drive system configuration of the hybrid vehicle will be described. FIG. 1 is an overall system diagram showing a hybrid vehicle driven by rear wheels of the first embodiment. As shown in FIG. 1, the drive system of the hybrid vehicle in the first embodiment includes an engine E, a flywheel FW, a first clutch CL1, a motor generator MG, a second clutch CL2, an automatic transmission AT, It has 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 a gasoline engine or a diesel engine, and the valve opening degree of the throttle valve and the like are controlled based on a control command from an engine controller 1 described later. The engine output shaft is provided with a flywheel FW.

  The first clutch CL1 (corresponding to the second engagement element described in the claims) is a clutch interposed between the engine E and the motor generator MG, and a control command from the first clutch controller 5 described later. On the basis of the above, engagement / release including slip engagement and slip release is controlled by the control hydraulic pressure generated by the first clutch hydraulic unit 6.

  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 “power running”), 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 (corresponding to the first engagement element described in the claims) is a clutch interposed between the motor generator MG and the left and right rear wheels RL, RR. Based on the control command, the engagement / release including slip engagement and slip release is controlled by the control oil pressure generated by the second clutch hydraulic unit 8.

  The automatic transmission AT is a transmission that automatically switches the stepped gear ratio such as 5 forward speeds, 1 reverse speed, etc. according to the vehicle speed, accelerator opening, etc., and the second clutch CL2 is newly added as a dedicated clutch However, some frictional engagement elements are used among a plurality of frictional engagement elements that are engaged at each gear stage of the automatic transmission AT. Details will be described later.

  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. 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 in which the first clutch CL1 is disengaged and travels using only the power of the motor generator MG as a power source. 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.

  The third travel mode is an engine-use slip travel mode (hereinafter referred to as “WSC (Wet Start Clutch) travel mode) in which the first clutch CL1 is engaged and the second clutch CL2 is slip-controlled and the engine E is included in the power source. For short). This mode achieves creep running especially when the battery SOC is low or the engine water temperature is low. Furthermore, in this mode, the driving force can be output while starting the engine when starting from the engine stopped state.

  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 drive wheels are moved using only the engine E as a power source. In the “motor assist travel mode”, the drive wheels are moved by using the engine E and the motor generator MG as power sources. The “running power generation mode” causes the motor generator MG to function as a generator at the same time as the drive wheels RR and RL are moved using the engine E as a power source.

  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.

  Next, the control system of the hybrid vehicle will be described. As shown in FIG. 1, the hybrid vehicle control system according to 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 a CAN communication line 11 that can exchange information with each other. ing.

  The engine controller 1 inputs the engine water temperature from the engine water temperature sensor 1 a and the engine speed information from the engine speed sensor 12, and according to the target engine torque command from the integrated controller 10, the engine operating point (Ne, Te For example, to a throttle valve actuator (not shown). In the engine controller 1, an engine torque estimation unit 1b that estimates the engine torque Teng based on the fuel injection amount of the engine E, the throttle opening, and the like is provided. Information on the engine speed Ne and the estimated engine torque Teng 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 rotation position of the motor generator MG, and the motor operating point (Nm, Tm) of the motor generator MG in accordance with a target motor generator torque command or the like from the integrated controller 10. Is output to the inverter 3. The motor controller 2 monitors the battery SOC indicating the state of charge of the battery 4. The battery SOC information is used for control information of the motor generator MG and is supplied to the integrated controller 10 via the CAN communication line 11. To do.

  Further, a motor generator torque estimation unit 2b that estimates the motor generator torque Tmg based on the value of the current flowing through the motor generator MG (the driving torque and the regenerative torque are distinguished based on whether the current value is positive or negative) is provided. Information on the estimated motor generator torque Tmg is supplied to the integrated controller 10 via the CAN communication line 11.

  The first clutch controller 5 inputs sensor information from the first clutch hydraulic pressure sensor 14 and the first clutch stroke sensor 15, and according to the first clutch control command from the integrated controller 10, the first clutch CL1 is engaged / released. A command to control is output to the first clutch hydraulic unit 6. 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 sensor information from the accelerator opening sensor 16, the vehicle speed sensor 17, and the second clutch hydraulic pressure sensor 18, and engages / disengages the second clutch CL2 in response to the second clutch control command from the integrated controller 10. A command for controlling opening is output to the second clutch hydraulic unit 8 in the AT hydraulic control valve. Information on the accelerator pedal opening APO and the vehicle speed VSP is supplied to the integrated controller 10 via the CAN communication line 11.

  The brake controller 9 inputs sensor information from a wheel speed sensor 19 and a brake stroke sensor 20 that detect the wheel speeds of the four wheels. For example, when the brake is depressed, braking is performed with respect to the required braking force obtained from the brake stroke BS. When the braking force 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 (hydraulic braking force or motor braking force).

  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 a motor rotation speed Nm (= ωmg), and a second clutch. A second clutch output speed sensor 22 that detects the output speed N2out, a second clutch torque sensor 23 that detects the second clutch torque TCL2, a brake hydraulic pressure sensor 24, and a temperature sensor that detects the temperature of the first clutch CL1. Information from 10a and the temperature sensor 10b that detects the temperature of the second clutch CL2 and information obtained through 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 based on 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.

  Below, the control calculated by the integrated controller 10 of Example 1 is demonstrated using the block diagram shown in FIG. For example, this calculation is performed by the integrated controller 10 every control cycle of 10 msec. The integrated controller 10 includes a target driving force calculation unit 100, a mode selection unit 200, a target charge / discharge calculation unit 300, 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 pedal opening APO and the vehicle speed VSP using the target driving force map shown in FIG.

  The mode selection unit 200 calculates a target mode from the accelerator pedal opening APO and the vehicle speed VSP using the EV-HEV selection map shown in FIG. However, if the battery SOC is equal to or less than the predetermined value, the “HEV travel mode” is forcibly set as the target mode. In the EV-HEV selection map, the WSC mode is set in order to output a large driving force when the accelerator pedal opening APO is large in the low vehicle speed range. The HEV → WSC switching line or EV → WSC switching line is set in a region lower than the vehicle speed VSP1 at which the rotational speed is smaller than the idle rotational speed of the engine E when the automatic transmission AT is in the first gear. A hatched area in FIG. 4 is an area where the HEV traveling mode is switched to the WSC traveling mode, and a shaded area in FIG. 4 is an area where the WSC traveling mode is switched to the EV traveling 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.

  The operating point command unit 400 uses the accelerator pedal opening APO, the target driving force tFoO, the target mode, the vehicle speed VSP, and the target charging / discharging power tP as a target for reaching the operating point, as a transient target engine torque. And target motor generator torque, target second clutch engagement torque, target automatic shift shift, and first clutch solenoid current command. The operating point command unit 400 is provided with an unillustrated engine start control unit that starts the engine E when the EV travel mode is changed to the HEV travel mode.

  The shift control unit 500 drives and controls the solenoid valve in the automatic transmission AT so as to achieve each clutch engagement torque and the target shift stage according to a preset shift schedule. In this shift schedule, a target gear stage is set in advance based on the vehicle speed VSP and the accelerator pedal opening APO, and an upshift line, a downshift line, and the like are set.

  Further, in the operating point command unit 400, a target engagement torque calculation unit 401 that calculates a target engagement torque based on the target driving force tFoO, and an engagement that controls the engagement torque of the second clutch CL2 to be the target engagement torque. A torque control unit 402 and a motor rotation speed control unit 403 that controls the rotation speed of the motor generator MG so that the rotation speed on the motor generator MG side is higher than the rotation speed on the drive wheel side of the second clutch CL2. Yes.

  Further, a motor torque control unit 404 that controls the motor generator torque Tmg based on the target driving force tFoO, and the engagement torque of the second clutch CL2 based on the estimated motor generator torque Tmg, engine torque Teng, and motor generator rotational speed ωmg. And a switching unit 406 for switching between control by the motor rotation speed control unit 403 and control by the motor torque control unit 404 based on the second clutch engagement torque estimated as the target engagement torque. ing.

(Reason for motor speed control and motor torque control)
Here, the reason for switching between the motor rotation speed control unit 403 and the motor torque control unit 404 will be described.

(Necessity 1): [Necessity to perform slip control of second clutch CL2]
When traveling at a certain vehicle speed, it is most efficient to fully engage the second clutch CL2, control the torque of the motor generator MG and the engine E, and control the torque of the drive wheels.

  On the other hand, when the vehicle starts, the motor generator rotational speed gradually increases from the state where the drive wheels are stopped. At this time, if the engine E is stopped and the first clutch CL1 is released, it is possible to start only by the driving force of the motor generator MG with the second clutch CL2 fully engaged.

  However, when the vehicle starts as described above, the motor generator MG becomes less efficient because it outputs extremely low rotation and high torque, which is not preferable. In addition, when the engine E start request is made and torque is required for engine cranking, the upper limit of the motor generator torque Tmg needs to be allowed to some extent, and when starting as described above There are times when sufficient starting performance cannot be ensured. Further, when the engine E is being driven, it is necessary to ensure the idling speed of the engine E, and if the second clutch CL2 is completely engaged, there is a possibility of causing an engine stall.

  Furthermore, when starting with only the motor generator MG, a greater driving force may be required during the start and an engine start request may be made. In order to meet this request, the first clutch CL1 is engaged and the engine clutch is engaged. Ranking will be executed. At this time, a large load is suddenly applied to the motor generator MG, and the motor generator rotational speed may be reduced at a stretch, which may cause fluctuations in driving wheel speed and driving torque.

  Therefore, at the time of start, the second clutch CL2 controls the fastening torque so as to achieve the target driving force, and maintains the slip state (slip control). At this time, the motor generator MG can cope with various start scenes by independently controlling control such as engine start while achieving the target driving force.

(Necessity 2): [Necessity to execute motor speed control during slip control]
As described above, when the torque of the motor generator MG is controlled during the slip control of the second clutch CL2, the engine generator MG achieves at least the target driving force, and if an engine start request is further made, It is necessary to drive by adding the torque required for ranking. The torque required for engine cranking and the torque transmitted to the engine via the first clutch CL1 are determined by the state of the engine, such as the engine water temperature, and the speed of the required engine start. Since the torque varies greatly depending on the fastening torque, it is necessary to add a torque that can reliably crank the engine to the motor generator torque when an engine start request is made.

  When the actual torque required for engine cranking is small, the load acting on motor generator MG becomes very small, and the rotational speed of motor generator MG increases at a stretch. At this time, since the second clutch CL2 only outputs a torque corresponding to the engagement torque to the drive wheels, the rotational speed of the drive wheels does not change suddenly. Therefore, the slip amount in the second clutch CL2 becomes excessive. This leads to a deterioration in durability of the second clutch CL2, which is not preferable.

  Therefore, when the second clutch CL2 is slip-controlled, motor rotation speed control is performed to control the rotation speed of the motor generator MG to maintain a predetermined rotation speed slightly higher than the rotation speed of the drive wheels. did. In order for motor generator MG to maintain a slightly higher rotational speed, a torque larger than the engagement torque of second clutch CL2 is required. Therefore, if the rotational speed control is performed, motor generator torque Tmg is inevitably higher than target driving force tFoO. Should be set higher.

  In addition, since a target rotational speed is set for motor generator MG, even if a large torque is generated in motor generator MG as a torque for achieving this target rotational speed, this target rotational speed will be greatly exceeded. There is no.

  Thereby, motor generator MG does not rotate excessively, and a decrease in durability of second clutch CL2 can be suppressed.

(Necessity 3): [Necessity of torque control after complete fastening]
Next, when a predetermined condition is satisfied, it is desirable to completely engage the second clutch CL2 from the viewpoint of durability of the second clutch CL2. However, if the second clutch CL2 is completely engaged while the motor generator MG is under motor speed control, there are the following problems.

  In general, the vehicle controls the torque of the drive wheels based on the driver's intention, that is, the accelerator pedal opening. In other words, the driver does not control the vehicle speed with the accelerator pedal, but controls the torque. When the motor generator MG is controlled at the rotational speed as described above with the second clutch CL2 fully engaged, torque corresponding to the deviation from the target rotational speed is output, and torque that does not match the driver's intention is generated. It is given to the driving wheel and gives a sense of incongruity.

  Also, from the viewpoint of durability, it is difficult to slip the second clutch CL2 steadily. After the start control processing and the like are completed, the second clutch CL2 is completely engaged, and the engine E and the motor generator MG It is desirable to switch to torque control.

  In the first embodiment, therefore, the slip control is shifted to the complete fastening when the predetermined condition is satisfied due to the necessity 1 and 2, and the motor rotation speed control is switched to the motor torque control according to the necessity 3. is there.

  Next, the starting clutch control process according to the first embodiment will be described. FIG. 6 is a flowchart showing the engagement control process of the second clutch CL2 at the start.

  In step S1, it is determined whether the second clutch CL2 is released and there is a start request. When this condition is satisfied, the process proceeds to step S2, and otherwise, the present control flow ends.

  In step S2, the target engagement torque is calculated based on the target driving force tFoO, and the engagement torque control is executed so that the engagement torque of the second clutch CL2 becomes the target engagement torque. Here, the actual engagement torque TCL estimated in any one of steps S5, S6, and S7 described later is used for detection of the actual engagement torque when executing the engagement torque control.

  The reason for executing the engagement torque control of the second clutch CL2 at the time of starting is that, as explained in the necessity 1, if the engagement torque of the second clutch CL2 is controlled, the input side (engine E or motor generator MG) This is because no more torque than the engagement torque of the second clutch CL2 is output to the drive wheel side, and a stable vehicle start can be achieved no matter how much the torque fluctuates.

  In step S3, motor rotation speed control is executed so that the rotation speed on the motor generator MG side is higher than the rotation speed on the drive wheel side of the second clutch CL2. The reason for executing the motor rotation speed control is as described in the necessity 2 above. Here, the motor rotation speed control refers to a value obtained by reading the rotation speed on the driving wheel side of the second clutch CL2 and adding a predetermined slip amount γ to the rotation speed on the driving wheel side on the motor generator side of the second clutch CL2. Set as target speed. Then, a target motor generator rotational speed is set in consideration of a predetermined gear ratio so that the target rotational speed can be achieved, and the motor generator MG is controlled so as to maintain this rotational speed. Therefore, a command value to motor generator MG is output based on a deviation between the target rotational speed and the actual rotational speed.

  At this time, how much torque is generated in motor generator MG is not a final control target. Therefore, the motor generator torque estimation unit 2b provided in the motor controller 2 estimates the motor generator torque based on the current value flowing through the motor generator MG, and transmits the estimated motor generator torque Tmg to the integrated controller 10.

  In this way, by using the motor generator MG as the rotational speed control and the second clutch CL2 as the engagement torque control, it is possible to ensure that the value corresponding to the engagement torque of the second clutch CL2 is reliably output to the drive wheels. This is because the motor generator MG needs to maintain its own rotational speed that is higher by a predetermined rotational speed γ than the rotational speed on the drive wheel side of the second clutch CL2, and the torque for maintaining this rotational speed is the second clutch. This is because it cannot be achieved unless it is higher than the fastening torque.

  In step S4, the engaged state of the first clutch CL1 is detected. When the clutch is disengaged, the process proceeds to step S5. When the clutch is engaged, the process proceeds to step S6. When the slip control is being performed, the process proceeds to step S7. Note that the engagement state of the first clutch CL1 is determined based on other control logic. When the engine is required to start (request for transition to the HEV travel mode), the slip control is performed and the engine E When the engine is starting and outputting torque (HEV travel mode), it is in the engaged state, and when it does not require the driving force of the engine E (EV travel mode), it is in the released state.

In step S5, the actual engagement torque TCL of the second clutch CL2 is estimated by the estimation model (1). Here, the estimation model (1) is expressed by the following equation.
Tmg + Img × dωmg / dt = TCL
Here, Img × dωmg / dt is an inertia torque of the motor generator MG.

In step S6, the actual engagement torque TCL of the second clutch CL2 is estimated by the estimation model (2). Here, the estimation model (2) is represented by the following equation.
Tmg + (Teng + α) + Iin × dωin / dt = TCL
Here, Iin × dωin / dt is an inertia torque of the engine E and the motor generator MG, and α is a variation of the engine torque Teng.

In step S7, the actual engagement torque TCL of the second clutch CL2 is estimated by the estimation model (3).
Here, the estimation model (3) is expressed by the following equation.
Tmg + Img × dωmg / dt−Teng-mg = TCL
Here, Teng-mg is an engagement torque of the first clutch CL1 provided between the engine E and the motor generator MG.

  In step S8, it is determined whether or not the estimated engagement torque TCL of the second clutch CL2 is within a predetermined range in consideration of the error a with respect to the target driving force tFoO. If it is within the predetermined range, the process proceeds to step S9. In other cases, Steps S2 to S9 are repeated until the fastening torque TCL falls within a predetermined range.

  In step S9, the control is performed so that the predetermined slip amount becomes zero from the control for securing the predetermined slip amount γ as the motor rotation speed control. That is, motor generator MG outputs a higher torque to ensure a predetermined slip amount γ, and naturally the rotational speed is higher than the rotational speed transmitted to the drive wheel side. If the second clutch CL2 is completely engaged in this state, the inertia torque on the input side of the second clutch CL2 is output to the drive wheel side, resulting in fluctuations in output torque, which may cause the driver to feel uncomfortable. is there.

  Further, if the engagement torque TCL of the second clutch CL2 is simply increased while the motor rotation speed control is being performed, the motor generator MG outputs a large drive torque to ensure the slip amount γ.

  Therefore, the slip amount of the second clutch CL2 is gradually decreased by controlling the motor rotation speed control so that the slip amount becomes zero and gradually decreasing the torque of the motor generator.

  In step S10, it is determined whether or not the slip amount of the second clutch CL2 is less than a predetermined value β representing an allowable range in which torque fluctuation when fully engaged is considered to be small. When the slip amount is less than the predetermined value β, the process proceeds to step S11. In other cases, the process returns to step S9 to control the slip amount to be small.

  In step S11, the motor speed control is switched to the motor torque control, and in step S12, the second clutch CL2 is completely engaged.

  Next, the operation based on the control process will be described. In describing the operation of the first embodiment, a comparative example will be used to clarify the features. FIG. 7 is a time chart when the engagement control of the second clutch CL2 in the comparative example is performed.

  For the sake of explanation, the notation on the time chart is defined as follows. The input torque is the input side of the second clutch CL2, and is a value that takes into account the engine torque Teng, the motor generator torque Tmg, and the engaged state of the first clutch CL1. The clutch torque is an engagement torque of the second clutch CL2. The slip rotation speed is the slip amount of the second clutch CL2. The output torque is torque transmitted to the drive wheels. The comparative example represents a case where the engagement torque of the second clutch CL2 is controlled while the input torque is constant.

  As shown in FIG. 7, the input torque is constant, and the second clutch CL2 generates a predetermined slip amount by the slip control. Note that the input side of the second clutch CL2 rotates at a higher speed than the output side. At this time, when the second clutch CL2 is completely engaged from the slip control, since the input torque is controlled to be constant, the engagement torque of the second clutch CL2 is increased to suppress the input side rotational speed of the second clutch CL2. (See (i) in FIG. 7).

  At this time, the load on the input side increases and the rotational speed starts to decrease, but the input torque itself is not changed by the constant input torque control. At this time, the inertia torque on the input side is output to the output side due to the change in the rotational speed on the input side, and the output torque varies. As a result, the driver may feel uncomfortable.

  FIG. 8 is a time chart when the engagement control of the second clutch CL2 in the first embodiment is performed. In the description of the action based on the comparison with the comparative example, the solid line in FIG. 8 represents the action of the first embodiment.

  As shown in FIG. 8, the input torque is shown to be constant, but this torque is merely the torque required to secure the slip amount of the second clutch CL2, and in particular, the input torque constant control. Is not performed (see (ii) in FIG. 8).

  In this state, when the estimated engagement torque TCL of the second clutch CL2 falls within a predetermined range in consideration of the error a with respect to the target driving force tFoO, the motor rotation speed control is executed so that the slip amount becomes zero ( (See (iii) in FIG. 8). Therefore, in order for the slip amount to become zero, the inertia torque is absorbed by lowering the input torque, so the output torque does not vary.

  When the slip amount becomes substantially zero, the motor speed control is switched to the motor torque control, and the second clutch CL2 is completely engaged. Therefore, since the motor torque control is executed in a state where the second clutch CL2 is completely engaged, a value corresponding to the target driving force is output as the output torque. As described above, in the configuration according to the first embodiment, the second clutch CL2 can be completely engaged without causing fluctuation in the output torque.

  Next, functions and effects based on other viewpoints in the control configuration of the first embodiment will be described. The engagement torque of the second clutch CL2 can be roughly estimated from the amount of hydraulic pressure supplied to the second clutch CL2, and the like. However, the second clutch CL2 has a secular change of the clutch plate and individual variations, and a characteristic change due to the oil temperature is also large. Therefore, accurate estimation is not always possible with hydraulic control-based estimation.

  Here, it is assumed that the actual engagement torque of the second clutch CL2 has been estimated to be low. A dotted line in FIG. 8 is a time chart in a case where the estimation is made lower. In this case, since a fastening torque higher than the target driving force tFoO is generated as the command value, the driving torque higher than the higher fastening torque is generated to secure the slip amount γ.

  In this state, when the target driving force tFoO and the lower estimated engagement torque substantially coincide with each other, the input torque is reduced, the second clutch CL2 is completely engaged, and the motor rotational speed control is switched to the motor torque control. . At this time, after the second clutch CL2 is completely engaged, the torque controlled by the engine E and the motor generator MG is output as the output torque.

  Since the torque control of the engine E and the motor generator MG is very accurate, a value substantially coincident with the target driving force tFoO can be output. At this time, the output torque becomes smaller than the output torque at the time of motor rotation speed control, which may give the driver a feeling of strangeness.

  That is, assuming the control configuration of the first embodiment, the estimation accuracy of the engagement torque of the second clutch CL2 is very important. Also, even if there is some estimation error, it is very important that the estimated values before and after the control switching are the same.

  Therefore, as described above, the estimated torque of the engine E and the motor generator MG is very accurate, and the estimated values match before and after the control switching (the basis of the estimation is the same: for example, the motor generator current, etc.) The engagement torque of the second clutch CL2 is estimated using the values of the engine torque Teng and the motor generator torque Tmg, and the clutch control is executed based on the estimated engagement torque.

  As a result, even if the motor rotation speed control is switched to the motor torque control, the torque can be controlled without causing a torque step, and stable running can be realized without causing fluctuations in the output torque. .

  As described above, in the configuration of the first embodiment, the following effects can be obtained.

  (1) The second clutch CL2 interposed between the power source (the engine E and the motor generator MG) and the driving wheel, and the target engagement torque is calculated based on the target driving force tFoO, and the second clutch CL2 is engaged. The engagement torque control unit 402 that controls the torque to be the target engagement torque, and the rotational speed of the power source is controlled so that the rotational speed on the power source side is higher than the rotational speed on the drive wheel side of the second clutch CL2. A motor rotation speed control unit 403 serving as a rotation speed control unit and an engagement torque estimation unit 405 that estimates the engagement torque of the second clutch CL2 based on the torque of the power source are provided.

  Therefore, the actual engagement torque of the second clutch CL2 can be accurately estimated from the torque of the power source, and fluctuations in output torque to the drive wheels can be suppressed.

  (2) The engagement torque estimation unit 405 estimates the engagement torque of the second clutch CL2 based on the estimation models (1) to (3) corresponding to the engagement state of the engine torque Teng, the motor generator torque Tmg, and the first clutch CL1. It was decided to.

  Therefore, it is possible to accurately estimate the engagement torque by accurately reflecting the state on the input side of the second clutch CL2. In addition, since the engagement torque can be accurately estimated, no matter how the input side of the second clutch CL2 is controlled, the output torque to the drive wheels when the second clutch CL2 transitions from the slip state to the complete engagement state. Variations can be suppressed.

  (3) A motor torque control unit 404 that controls the torque of the motor generator MG to be a target torque, and a switching unit 406 that switches from the motor rotation speed control unit 403 to the motor torque control unit 404 when a predetermined condition is satisfied. And with.

  Therefore, torque control according to the driver's intention can be realized at the time of complete engagement while avoiding deterioration of clutch durability due to excessive rotation of motor generator MG during slip control of second clutch CL2. In addition, since the torque estimated before control switching and the torque estimated after control switching have the same estimation accuracy, fluctuations in estimated values due to control switching can be eliminated, and torque steps are further suppressed. can do.

  (4) The predetermined condition is that the difference between the estimated fastening torque TCL and the target driving force tFoO (target fastening torque) is not more than a predetermined value. Therefore, the torque step at the time of control switching can be suppressed.

  (5) When the difference between the estimated fastening torque TCL and the target driving force tFoO (target fastening torque) is equal to or less than a predetermined value, the motor rotational speed control unit 403 rotates the driving wheel side rotational speed and the power source side rotational speed. The number of revolutions of the power source was controlled so that the number matched. Therefore, even if complete fastening is performed at the time of control switching, the torque step can be suppressed.

  (6) The predetermined condition is that the difference between the rotational speed on the power source side and the rotational speed on the drive wheel side is less than or equal to a predetermined value. Therefore, it becomes possible to reduce the change of the inertia torque at the time of complete fastening, and it is possible to suppress the torque step at the time of control switching.

  (7) The switching unit 406 switches from the motor rotation number control unit 403 to the motor torque control unit 404 and then fully engages the second clutch CL2. Therefore, torque control according to the driver's intention can be achieved.

  As described above, the first embodiment has been described. However, the present invention is not limited to the above-described embodiment, and other embodiments in which the invention can be carried out are allowed. In the first embodiment, only the configuration for switching from the motor rotation speed control to the motor torque control is shown. However, the operation state of the power source may be switched, and the engine or the like may be similarly switched as control. In short, any configuration may be used as long as the estimated values of torque output to the drive wheels before and after the switching match.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall system diagram illustrating a rear-wheel drive hybrid vehicle to which an overheat-response mode transition control according to a first embodiment is applied. FIG. 3 is a control block diagram illustrating an arithmetic processing program in the integrated controller according to the first embodiment. It is a figure which shows an example of the target driving force map used for target driving force calculation in the target driving force calculating part of FIG. It is a figure which shows the EV-HEV selection map used for selection of the target mode in the mode selection part of FIG. It is a figure which shows an example of the target charging / discharging amount map used for the calculation of target charging / discharging electric power in the target charging / discharging calculating part of FIG. 6 is a flowchart showing a second clutch engagement control process at the time of start of the first embodiment. It is a time chart at the time of performing fastening control of the 2nd clutch in a comparative example. 6 is a time chart when performing engagement control of a second clutch in the first embodiment.

Explanation of symbols

E engine
FW flywheel
CL1 1st clutch
MG motor generator
CL2 2nd clutch
AT automatic transmission
PS propeller shaft
DF differential
DSL left drive shaft
DSR right drive shaft
RL Left rear wheel (drive wheel)
RR Right rear wheel (drive wheel)
FL Left front wheel
FR Right front wheel 1 Engine controller 2 Motor controller 3 Inverter 4 Battery 5 First clutch controller 6 First clutch hydraulic unit 7 AT controller 8 Second clutch hydraulic unit 9 Brake controller 10 Integrated controller 24 Brake hydraulic sensor
100 Target driving force calculator
200 Mode selection section
300 Target charge / discharge calculator
400 Operating point command section
500 Shift control

Claims (4)

A first fastening element interposed between the power source and the drive wheel;
A fastening torque control means for calculating a target fastening torque based on a required driving force and controlling the fastening torque of the first fastening element to be a target fastening torque;
Torque control means for controlling the torque of the power source to be a target torque;
A rotational speed control means for controlling the rotational speed of the power source so that the rotational speed on the power source side is higher than the rotational speed on the drive wheel side of the first fastening element;
A fastening torque estimating means for estimating a fastening torque of the first fastening element based on a torque of the power source;
When the fastening torque of the first fastening element is controlled by the fastening torque control means and the rotational speed of the power source is controlled by the rotational speed control means, the estimated fastening torque and the target fastening Switching means for switching from the rotational speed control means to the torque control means when the difference from the torque is less than or equal to a predetermined value ;
Control device for a vehicle characterized by comprising a. The vehicle control device according to claim 1,
The rotational speed control means controls the rotational speed of the power source so that the rotational speed on the drive wheel side coincides with the rotational speed on the power source side when the difference is equal to or less than a predetermined value. A vehicle control device that switches to a torque control means. The vehicle control device according to claim 1 or 2,
The power source is composed of an engine, a motor, and a second fastening element interposed between the engine and the motor,
The vehicle control apparatus, wherein the fastening torque estimating means estimates a fastening torque of the first fastening element based on an estimation model corresponding to a torque of the power source and a fastening state of the second fastening element. The vehicle control device according to any one of claims 1 to 3,
The control device for a vehicle, wherein the switching means completely fastens the first fastening element after switching from the rotation speed control means to the torque control means.

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