JP4914806B2 - Rear wheel toe angle control device and rear wheel toe angle control vehicle - Google Patents

Description

  The present invention relates to a rear wheel toe angle control device and a rear wheel toe angle control vehicle, and more particularly to a rear wheel toe angle control device used for a vehicle that performs a regenerative braking operation, such as an electric vehicle and a hybrid vehicle.

  In many cases, an electric vehicle, a hybrid vehicle, and the like are equipped with a motor / generator that selectively performs driving and power generation of the vehicle, and depending on the driving state of the vehicle, for example, a repulsive force in which the accelerator pedal is not depressed. During driving or downhill driving, during braking operation when the brake pedal is depressed or during deceleration operation, the motor generator is driven by rotating the wheel and used as a generator to perform regenerative braking operation to charge the on-vehicle storage battery (for example, Patent Document 1).

  As a front and rear four-wheel vehicle, there is a rear wheel toe angle control vehicle in which an electric actuator is incorporated in a rear wheel suspension mechanism and a rear wheel toe angle can be variably set (increased or decreased) by the actuator. (For example, see Patent Documents 2 and 3).

Rear wheel toe angle control sets the rear wheel toe angle according to parameters indicating the vehicle motion state, such as steering angle given by the steering wheel, traveling speed (vehicle speed), longitudinal acceleration, lateral acceleration, yaw rate, etc. When braking, the rear wheel is usually toe-in.
Japanese Patent No. 3373759 Japanese Patent No. 3476972 Japanese Patent Publication No. 8-25482

  If the above-described rear wheel toe angle control is applied as it is to an electric vehicle or a hybrid vehicle, the regenerative braking operation is performed with the rear wheels set to toe-in during deceleration and braking.

  In the toe-in setting, the tire running resistance is larger than in the zero toe angle state (neutral state in which the left and right rear wheels are parallel to each other), and the braking force always works. For this reason, as shown in FIG. 4 (a), the total braking force of the vehicle body during deceleration / braking in the toe-in electric vehicle and hybrid vehicle is as follows: The total value of the regenerative braking force and the braking force by toe-in is the same. With the same total braking force (required braking force), the regenerative braking force is reduced by the amount of braking force by toe-in, and the energy recovery efficiency by regenerative braking is reduced.

  The problem to be solved by the present invention is to link the regenerative brake control and the rear wheel toe-in control in an electric vehicle, a hybrid vehicle, etc., and to improve the energy recovery efficiency by the regenerative brake.

  A rear wheel toe angle control device according to the present invention includes a motor / generator that selectively performs driving and power generation of a vehicle, and performs a regenerative braking operation using the motor / generator according to the driving state of the vehicle. When the regenerative braking operation is performed when the information about whether or not the regenerative braking operation is performed is input and the regenerative braking operation is performed. Regenerative braking toe angle setting means for performing processing for reducing the rear wheel toe angle or processing for reducing the rear wheel toe angle to zero.

  The rear wheel toe angle control device according to the present invention preferably cancels the setting of the rear wheel toe angle by the toe angle setting means at the time of regenerative braking when the braking force of the vehicle is greater than or equal to a threshold value, and the rear wheel becomes toe-in. Set the rear wheel toe angle.

  A rear wheel toe angle control vehicle according to the present invention is equipped with a motor / generator that selectively performs driving and power generation of the vehicle, and performs a regenerative braking operation using the motor / generator according to the driving state of the vehicle. An actuator for imparting a toe angle to a rear wheel, wherein the actuator receives a toe angle command signal from the rear wheel toe angle control device according to any one of claims 1 to 3, and The toe angle of the rear wheel is increased or decreased according to the value of the toe angle command signal. When the value of the toe angle command signal input by the actuator is zero, the toe angle is automatically reduced to zero by the running resistance received by the rear wheel. This is a rear wheel toe angle control vehicle.

  According to the rear wheel toe angle control device and the rear wheel toe angle control vehicle according to the present invention, when the regenerative brake operation is performed, the rear wheel toe angle is larger than when the regenerative brake operation is not performed. The toe angle setting of the rear wheels approaches a neutral state in which the left and right rear wheels are parallel to each other, or the rear wheels are in a neutral state, and the braking force due to toe-in is reduced or zero. As a result, under the same necessary brake force, the regenerative brake force is increased by the amount of the brake force generated by toe-in, and the energy recovery efficiency by the regenerative brake is improved.

  Hereinafter, an embodiment of a rear wheel toe angle control device and a rear wheel toe angle control vehicle according to the present invention will be described with reference to FIGS.

  The rear wheel toe angle control vehicle of this embodiment is a hybrid vehicle with a rear wheel toe angle control device, and as shown in FIG. 1, as an in-vehicle prime mover driving left and right front wheels 10R, 10L, an internal combustion engine ( (Hereinafter referred to as an engine) 20 and a motor generator (hereinafter referred to as MG) 30. The MG 30 is electrically connected to a battery power source (storage battery) 32 via an inverter 31.

  The MG 30 is supplied with electric power from the battery power source 32 by the switching operation of the inverter 31 and functions as a motor that rotationally drives the front wheels 10R, 10L, and is rotated by the rotation of the front wheels 10R, 10L by running the vehicle. The state of functioning as a generator for charging 32 is selectively performed, that is, the vehicle is driven and generated. An operation mode in which the MG 30 functions as a generator and charges the battery power source 32 is referred to as a regenerative brake mode.

  The rear wheel toe angle control vehicle includes an engine electronic control unit (hereinafter referred to as “engine ECU”) 41 that controls the engine 20, and a motor / generator electronic control unit (hereinafter referred to as “MG ECU”) 42 that controls the MG 30 by the inverter 31. And an upper hybrid electronic control unit (hereinafter referred to as a hybrid ECU) 40 that is connected to both the engine ECU 41 and the MG ECU 42 so as to be capable of bidirectional communication and generally controls these ECUs.

  The hybrid ECU 40 is based on a microcomputer system, and receives sensor signals (indicated by reference numeral 43) from various sensors such as a vehicle speed sensor, an accelerator opening sensor, and a brake sensor, and from the input sensor signal 43 and the engine ECU 41. The driving state of the vehicle is detected by arithmetic processing based on the driving state of the engine 20 obtained. The hybrid ECU 40 transmits an operation command signal to the engine ECU 41 and the MG ECU 42 according to the driving state of the vehicle obtained by the arithmetic processing, and sends sensor signals necessary for the respective control to the engine ECU 41 and the MG. It transmits to ECU42.

  The hybrid ECU 40 has a regenerative brake determination unit 44. The regenerative brake determination unit 44 determines whether or not to set the regenerative brake mode from the driving state of the vehicle obtained by the calculation process, and outputs a regenerative brake command signal to the MG ECU 42. For example, the regenerative brake determination unit 44 is configured to generate a regenerative brake command signal for setting a regenerative brake mode during repulsive driving or downhill driving when the accelerator pedal is not depressed, or during braking operation or deceleration operation when the brake pedal is depressed. Is transmitted to the MG ECU 42.

  The regenerative brake determination unit 44 periodically transmits information regarding whether or not the regenerative brake mode is set, for example, a flag indicating whether or not the regenerative brake operation is being performed, to the rear wheel toe angle ECU 60 described later.

  The engine ECU 41 is based on a microcomputer system, and receives an operation command signal and a sensor signal from the hybrid ECU 40, and also includes an intake air flow rate sensor, an intake pipe pressure sensor, a throttle opening sensor, a crank angle sensor, an engine cooling water. Sensor signals (indicated by reference numeral 45) are input from various sensors such as a temperature sensor, and command values for fuel injection amount / injection timing control, ignition timing control, etc. are calculated by arithmetic processing according to these information signals. Is output to the fuel injection amount / injection timing control unit and the ignition timing control unit of the engine 20.

  Thus, the fuel injection amount / injection timing and ignition timing of the engine 20 are controlled.

  The MG ECU 42 is based on a microcomputer system, and receives operation command signals and sensor signals from the hybrid ECU 40 and sensor signals (indicated by reference numeral 46) from various sensors such as a battery voltage sensor and a current sensor. A command value such as a switching operation of the inverter 31 is calculated by an arithmetic process corresponding to these information signals, and the command signal is output to the inverter 31.

  As a result, the operation mode and operation state of the MG 30 are controlled.

  Electric linear actuators 50R and 50L are incorporated in the suspension portions 12R and 12L of the left and right rear wheels 11R and 11L. The linear actuators 50R and 50L are individually controlled by a rear wheel toe angle electronic control unit (hereinafter referred to as a rear wheel toe angle ECU) 60, and the toe angles of the left and right rear wheels 11R and 11L are individually variably set by linear operation. (Increase / decrease setting).

  The linear actuators 50R and 50L receive a toe angle command signal from the rear wheel toe angle ECU 60, and individually increase or decrease the toe angles of the rear wheels 11R and 11L according to the value of the toe angle command signal.

  When the value of the toe angle command signal input by the linear actuators 50R and 50L is zero, in other words, when the linear actuators 50R and 50L correspond to power interruption, the rear wheels 11R and 11L Naturally, the toe angle is zero. The zero toe angle state is a neutral state in which the left and right rear wheels 11R and 11L are parallel to each other and neither toe-in nor toe-out.

  The rear wheel toe angle ECU 60 is based on a microcomputer system, and receives sensor signals (indicated by reference numeral 61) from various sensors such as a vehicle speed sensor, a steering angle sensor, a longitudinal acceleration sensor, a lateral acceleration sensor, a yaw rate sensor, By a calculation process according to the input sensor signal, a normal rear wheel toe angle command value equivalent to the conventional one is calculated, and the toe angle command signal is output to the linear actuators 50R and 50L.

  As a result, the linear actuators 50R and 50L are controlled, and rear wheel toe angle control is performed.

  The rear wheel toe angle ECU 60 includes a regenerative braking toe angle setting unit 62 as one of event control means. The rear wheel toe angle ECU 60 periodically receives a flag indicating whether or not a regenerative brake operation is being performed from the regenerative brake determination unit 44 of the hybrid ECU 40 through communication with the hybrid ECU 40. When the rear wheel toe angle ECU 60 receives a flag indicating that the regenerative braking operation is being performed, the rear wheel toe angle ECU 60 surpasses the above-mentioned normal rear wheel toe angle command value, and under the same toe angle setting conditions, Compared to when the regenerative braking operation is not performed, the rear wheel toe angle is reduced, that is, the rear wheel toe angle is brought close to zero, or the toe angle command signal for making the rear wheel toe angle zero is given to the linear actuators 50R and 50L. Output.

  Thereby, at the time of regenerative braking operation, the rear wheel toe angle is reduced or becomes zero, and the rear wheels 11R and 11L approach or become in a neutral state. By this control, the braking force due to toe-in is reduced or zero, and as shown in FIGS. 4 (a) and 4 (b), the braking force due to toe-in is equal to the regenerative braking force under the same necessary braking force. The energy recovery efficiency by regenerative braking is increased.

  When the value of the toe angle command signal input by the linear actuators 50R and 50L is zero, the linear actuators 50R and 50L are equivalent to power interruption, and the rear wheels 11R and 11L are naturally caused by the running resistance received by the rear wheels 11R and 11L. Since the toe angle is in a zero state, the left and right rear wheels 11R and 11L are in a neutral state parallel to each other only by setting the value of the toe angle command signal to the linear actuators 50R and 50L to zero.

  Further, the rear wheel toe angle ECU 60 sets the rear wheel toe angle by the regenerative braking toe angle setting unit 62 when the braking force of the vehicle, for example, deceleration, or the brake fluid pressure is large braking with a threshold value or more. Cancel and control to set the rear wheel toe angle at which the rear wheels 11R and 11L become a predetermined toe-in.

  As a result, during large braking, the rear wheels 11R and 11L are in a predetermined toe-in, and braking stability is improved.

  It should be noted that the toe angle of the rear wheels 11R and 11L gives a predetermined time constant to the change in the toe angle command value in order to avoid a sudden change in the rear wheel toe angle state in both cases of reduction and increase. In this case, it is preferable to carry out gradually. The degree of gradual change of the toe angle may be set to an optimum value in consideration of the required toe angle control response.

  Next, the procedure of hybrid control by the hybrid ECU 40 and rear wheel toe angle control by the rear wheel toe angle ECU 60 will be described with reference to the flowcharts shown in FIGS.

  The hybrid control routine shown in FIG. 2 is a time interruption routine that is repeatedly executed at predetermined time intervals. First, sensor signals are input from various sensors (step S11), and predetermined values corresponding to the input values of the sensor signals are input. By this calculation process, the motor / generator control process for determining the operation mode and the operation state of the MG 30 is performed (step S12).

  Next, it is determined whether or not the determined operation mode of the MG 30 is the regenerative brake mode (step S13). If it is in the regenerative brake mode, the regenerative brake operation command signal is output (transmitted) to the MG ECU 42 (step S14), and then the rear wheel toe angle ECU 60 is notified that the regenerative brake mode is set ( Step S15).

  On the other hand, when the determined operation mode of the MG 30 is not the regenerative braking mode, that is, when it is the traveling drive mode, the motor / generator operation command signal based on the operation state determined in step S12 is output to the MG ECU 42. (Send) (Step S16).

  Next, an engine control process for determining the operating state of the engine 10 is performed by a predetermined calculation process (step S17), and an operation command signal is output (transmitted) to the engine ECU 41 (step S18).

  The rear wheel toe angle control routine shown in FIG. 3 is a time interruption routine that is repeatedly executed every predetermined time. First, sensor signals are input from various sensors (step S21).

  Next, it is determined whether or not the regenerative brake mode is set with reference to the notification from the hybrid ECU 40 (step S22). If it is in the regenerative braking mode, it is determined whether or not the current braking force of the vehicle is greater than or equal to a predetermined threshold (step S23). If the current braking force of the vehicle is not equal to or greater than a predetermined threshold value, processing for reducing the rear wheel toe angle is performed (step S24).

  The rear wheel toe angle reduction process is a process of gradually reducing the rear wheel toe angle to a predetermined ratio of the current rear wheel toe angle, for example, 50% or 90%, or the rear wheel toe angle is gradually reduced to zero. It is processing to do.

  Even in the regenerative braking mode, if the braking force of the current vehicle is equal to or greater than a predetermined threshold, the rear wheel toe angle reduction process is not performed, and the toe angle setting process in which the rear wheels 11R and 11L are toe-in is performed (step S25). .

  When not in the regenerative braking mode, a normal rear wheel toe angle control process for determining a normal rear wheel toe angle is performed by a predetermined calculation process according to the input value of the sensor signal (step S26).

  Then, the rear wheel toe angle command signal is output to the linear actuators 50R and 50L (step S27).

  By the above-described series of controls, the regenerative braking force is increased under the same necessary braking force, and the energy recovery efficiency by the regenerative braking is improved.

  In the above-described embodiment, the hybrid vehicle has been described. However, the rear wheel toe angle control device according to the present invention is not limited to this, and can be similarly applied to an electric vehicle that performs a regenerative braking operation.

1 is a block diagram showing one embodiment of a hybrid vehicle with a rear wheel toe angle control device to which a rear wheel toe angle control device according to the present invention is applied. FIG. It is a flowchart which shows the hybrid control routine of the hybrid vehicle with a rear-wheel toe angle control apparatus by this embodiment. It is a flowchart which shows the rear-wheel toe angle control routine of the hybrid vehicle with a rear-wheel toe angle control apparatus by this embodiment. (A), (b) is a graph which shows the brake component ratio of a hybrid vehicle with a rear-wheel toe angle control apparatus.

Explanation of symbols

10R, 10L Front wheel 11R, 11L Rear wheel 12R, 12L Suspension part 20 Internal combustion engine (engine)
30 Motor generator (MG)
31 Inverter 32 Battery power supply 40 Electronic control unit for hybrid (ECU for hybrid)
41 Electronic control unit for engine (ECU for engine)
42 Electronic control unit for motor / generator (ECU for MG)
44 Regenerative brake determination unit 50R, 50L Linear actuator 60 Electronic control unit for rear wheel toe angle (ECU for rear wheel toe angle)
62 Toe angle setting section during regenerative braking

Claims (4)

A motor / generator that selectively performs driving and power generation of the vehicle is installed, regenerative braking is performed using the motor / generator according to the driving state of the vehicle , and the rear wheel A rear wheel toe angle control device used in a vehicle for setting a corner and controlling a rear wheel toe angle,
When information on whether or not regenerative braking operation is being performed is input and regenerative braking operation is being performed, the regenerative braking operation is performed using the rear wheel toe angle under the same rear wheel toe angle setting conditions. rear wheel toe angle control system having a regenerative brake when the toe angle setting means for processing the low reduced compared with the case where no cracking. The rear wheel toe angle control device according to claim 1, wherein the rear wheel toe angle is set based on a sensor signal including at least a snake angle sensor.   3. The rear wheel toe angle at which the rear wheel is toe-in is set by canceling the setting of the rear wheel toe angle by the regenerative braking toe angle setting means when the braking force of the vehicle is greater than a threshold value. Rear wheel toe angle control device described.   A motor / generator that selectively drives the vehicle for driving and power generation is installed, and a regenerative braking operation is performed using the motor / generator according to the driving state of the vehicle, and a toe angle is given to the rear wheels. The actuator receives a toe angle command signal from the rear wheel toe angle control device according to any one of claims 1 to 3, and the rear wheel according to a value of the toe angle command signal. A rear wheel toe angle control vehicle that automatically increases or decreases the toe angle, and when the value of the toe angle command signal input by the actuator is zero, the toe angle is automatically reduced to zero by the running resistance received by the rear wheel.

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