JP2017081242A - Vehicular control apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a smooth transition of a vehicular travel state to a state corresponding to a post-switch shift position while suppressing the generation of tooth-clattering noise in a gear mechanism or the discomfort of a driver, when a shift position is switched between a forward travel position and a reverse travel position.SOLUTION: A main ECU and a brake ECU of an electric automobile performs: gradually changing an output torque of a motor so as to gradually approach a target value in accordance with an accelerator opening degree, when an accelerator is operated, and controlling a hydraulic brake device so as to apply braking torque to a drive wheel when a vehicle travels in a direction corresponding to a pre-switching shift position as a result of an accelerator operation after a shift position is switched between a forward travel position and a reverse position (S100-S160); and gradually decreasing braking torque to zero when a vehicular speed is reduced to zero (S170-S190).SELECTED DRAWING: Figure 2

Description

  The present disclosure provides control of a vehicle having a drive source coupled to a drive wheel via a gear mechanism, and a hydraulic brake device capable of applying a braking torque to at least the drive wheel regardless of whether or not the driver performs a brake operation. Relates to the device.

  Conventionally, as a control device for a vehicle having an automatic transmission that shifts and outputs engine rotation and an electric motor that is connected to a rotation shaft between the automatic transmission and a drive wheel, a shift position is a forward traveling position or When switching to the reverse travel position, there is known one that drives the second motor generator in the drive direction corresponding to the shift position after the switch to perform backlash of the drive system (see, for example, Patent Document 1). . In this way, when the shift position is switched to the travel position, the second motor generator is driven to loosen the drive system, thereby starting the vehicle with torque from the electric motor according to the driver's accelerator operation. The starting response at the time can be improved. Conventionally, a transmission as a control device for a hybrid vehicle having an engine, first and second electric motors having a power generation function, a power source including a planetary gear, and a transmission coupled to an output shaft of the power source is provided. When the vehicle is moving at a vehicle speed higher than the predetermined vehicle speed α when the shift position of the vehicle is switched to the reverse drive position, the second motor is generated so that a regenerative braking force is applied to the input member of the transmission. What makes it function as a machine is known (for example, refer patent document 2). As a result, when the rotational direction of the output torque of the power source is reversed by the transmission while the vehicle is running, torque in the direction opposite to the previous rotational direction is applied to the input member of the transmission. The drive torque output from the machine decreases. As a result, when the shift position is switched between the forward travel position and the reverse travel position while the vehicle is traveling, the vehicle speed can be quickly reduced and the speed change with the forward / reverse switching can be quickly performed. It becomes possible.

JP 2007-153110 A JP 2009-160252 A

  In the vehicle described in Patent Document 1, even when the shift position of the automatic transmission is switched between the forward travel position and the reverse travel position during traveling at an extremely low speed, the drive system of the second motor generator is used. Backlash will be performed. However, when the second motor generator is driven in the driving direction corresponding to the shift position after switching while the vehicle is traveling in the direction corresponding to the shift position before switching, the second motor generator is driven on the torque transmission path. In automatic transmissions and differential gears located on both sides, there is a risk that rattling noise will be generated due to switching of the gear surfaces on the meshing side of the gear teeth. Similarly, when the regenerative braking is performed by the second electric motor when the shift position is switched between the forward travel position and the reverse travel position as in the vehicle described in Patent Document 2, torque transmission is also performed. There is a risk that rattling noise may occur in planetary gears, transmissions, and the like located on both sides of the second electric motor on the path. In addition, when the shift position is switched between the forward travel position and the reverse travel position, after the shift position is switched, the driving state of the vehicle is suppressed while preventing the driver from feeling uncomfortable due to reverse travel. Must be smoothly shifted to a state corresponding to the shift position after switching.

  Therefore, the invention of the present disclosure suppresses the occurrence of rattling noise in the gear mechanism and the driver from feeling uncomfortable when the shift position is switched between the forward travel position and the reverse travel position. The main purpose is to smoothly shift the running state to a state corresponding to the shift position after switching.

  A vehicle control device according to the present disclosure includes a drive source connected to a drive wheel via a gear mechanism, and a hydraulic brake device capable of applying a braking torque to at least the drive wheel regardless of whether or not a driver performs a brake operation. A control device that slowly changes the output torque of the drive source so that it gradually approaches a target value corresponding to an accelerator operation amount when an accelerator operation is performed by a driver. After the shift position is switched between the forward travel position and the reverse travel position, at least the drive when the driver performs an accelerator operation and the vehicle travels in a direction corresponding to the shift position before the switch Braking start means for controlling the hydraulic brake device to apply the braking torque to the wheel, and at least the drive Brake release means for controlling the hydraulic brake device so as to gradually reduce the braking torque until it becomes zero when the braking torque is applied to the wheel and the vehicle speed becomes zero. .

  When the accelerator operation is performed by the driver of the vehicle, this control device slowly changes the output torque of the drive source so as to gradually approach a target value corresponding to the accelerator operation amount. In addition, this control device is used when an accelerator operation is performed by the driver after the shift position is switched between the forward travel position and the reverse travel position, and the vehicle travels in a direction corresponding to the shift position before the switch. In addition, the hydraulic brake device is controlled so that braking torque is applied to at least the driving wheel, and the braking torque is gradually reduced to zero in response to the braking torque being applied to at least the driving wheel and the vehicle speed becoming zero. Control the hydraulic brake device. In this way, after the shift position is switched between the forward travel position and the reverse travel position, the braking torque is applied to at least the drive wheels from the hydraulic brake device, so that the vehicle speed can be quickly reduced to zero and the driver can move backward. It is possible to suppress giving a sense of incongruity. Furthermore, by applying braking torque to the drive wheel farthest from the drive source in the torque transmission path, the output torque of the drive source is slowly changed so as to gradually approach the target value corresponding to the accelerator operation amount, thereby changing the shift position. After the switching, it is possible to satisfactorily suppress the occurrence of rattling noise due to the switching of the gear tooth meshing tooth surface in the gear mechanism. In addition, by gradually reducing the braking torque to the drive wheels until the vehicle speed becomes zero until the vehicle speed becomes zero, the output torque of the drive source is gradually brought closer to the target value corresponding to the accelerator operation amount. The running state can be smoothly shifted to a state corresponding to the shift position after switching. As a result, according to this control device, when the shift position is switched between the forward travel position and the reverse travel position, the occurrence of rattling noise in the gear mechanism and the feeling of discomfort to the driver are suppressed. It is possible to smoothly shift the vehicle running state to a state corresponding to the shift position after switching.

1 is a schematic configuration diagram illustrating a vehicle including a control device of the present disclosure. It is a flowchart which shows an example of the control routine performed by the control apparatus of this indication. FIG. 3 is a time chart illustrating how an accelerator pedal, a brake pedal, an operation state of a shift lever, a brake pressure, a driving torque, and a vehicle speed change when the control routine of FIG. 2 is executed.

  Next, embodiments for carrying out the invention of the present disclosure will be described with reference to the drawings.

  FIG. 1 is a schematic configuration diagram illustrating an electric vehicle 20 that is an example of a vehicle including the control device of the present disclosure. The electric vehicle 20 shown in the figure includes a motor MG as a drive source connected to the left and right drive wheels DW via a differential gear (gear mechanism) 25, an inverter 30 for driving the motor MG, and an inverter 30. A battery 40 that can exchange electric power with the motor MG, a hydraulic brake device 50 that can apply braking torque to the drive wheels DW and other wheels (not shown), and a main electronic control unit that controls the entire vehicle (hereinafter referred to as “main”). 70 ”).

  The motor MG is a known synchronous generator motor having a rotor in which a permanent magnet is embedded and a stator around which a three-phase coil is wound. The inverter 30 has, for example, six transistors as switching elements and six diodes connected in parallel to these transistors in the reverse direction, and is connected to the battery 40 via the boost converter 35. The step-up converter 35 has, for example, two transistors, two diodes connected in parallel to these transistors in the opposite direction, and a reactor (both not shown), and the voltage from the battery 40 is obtained. The voltage can be stepped up and supplied to the inverter 30, and the voltage from the inverter 30 can be stepped down and supplied to the battery 40. The battery 40 is, for example, a nickel hydride secondary battery or a lithium ion secondary battery having a rated output voltage of 200 to 300 V, and is a battery electronic control unit (hereinafter referred to as “battery ECU”) which is a microcomputer having a CPU (not shown). 45).

  The hydraulic brake device 50 includes a master cylinder 51, a plurality of brake pads (not shown) that sandwich a brake disk attached to each wheel and apply a braking torque (friction braking torque) to the corresponding wheel, and a corresponding brake. A plurality of wheel cylinders 52 that drive the pads, a hydraulic brake actuator 53 that supplies hydraulic pressure to each wheel cylinder 52, a brake electronic control unit (hereinafter referred to as “brake ECU”) 55 that controls the brake actuator 53, and the like. . Brake ECU55 is a microcomputer which has CPU etc. which are not illustrated.

  The brake ECU 55 detects the vehicle speed V from the vehicle speed sensor 75, the master cylinder pressure from a master cylinder pressure sensor (not shown) that detects the master cylinder pressure, the wheel cylinder pressure from a wheel cylinder pressure sensor (not shown), and the wheel speeds of the drive wheels DW, etc. A wheel speed or the like from a wheel speed sensor (not shown) is detected, and various signals are exchanged by communication with the main ECU 70 and the like. Further, the brake ECU 55 uses the hydraulic brake device 50 of the braking torque to be applied to the electric vehicle 20 based on the brake pedal stroke BS, the vehicle speed V, and the like from the brake pedal stroke sensor 57 that detects the depression amount of the brake pedal 56. The brake actuator 53 is controlled so that the friction braking torque corresponding to the share is applied to the drive wheels DW and the like. Further, the brake ECU 55 is configured to be able to control the brake actuator 53 so that the braking torque acts independently for each wheel regardless of whether or not the driver depresses the brake pedal 56.

  The main ECU 70 includes a CPU, a ROM that stores various control programs, a RAM that temporarily stores data, an input / output port, a communication port (all not shown), and the like. The main ECU 70 receives a shift position SP from the shift position sensor 72 that detects the shift position SP corresponding to the operation position (shift position) of the shift lever 71, and an accelerator pedal position sensor 74 that detects the depression amount of the accelerator pedal 73. The accelerator opening (accelerator operation amount) Acc, the vehicle speed V from the vehicle speed sensor 75, and the like are input via the input port.

  In this embodiment, the shift position SP that can be selected by operating the shift lever 71 includes a reverse (R) position as a reverse travel position, a forward drive, in addition to a parking (P) position and a neutral (N) position. A drive (D) position, a brake (B) position, and a sport (S) position are included as travel positions. Furthermore, in the electric vehicle 20 of the present embodiment, when the vehicle speed V is higher than zero and not more than a predetermined reference vehicle speed Vref (for example, about 2 to 3 km / h) in addition to when the vehicle is stopped (very low speed). During the travel at the time, the shift position SP from the forward travel position such as the drive position to the reverse position and the shift position SP from the reverse position to the forward travel position are permitted.

  Further, the main ECU 70 detects a rotor rotational position of the motor MG detected by a rotational position detection sensor (not shown), a phase current flowing in a three-phase coil of the motor MG detected by a current sensor (not shown), and a voltage sensor (not shown). A voltage between the battery 40 and the boost converter 35 (voltage before boost), a voltage between the boost converter 35 and the inverter 30 (voltage after boost), and the like are input. Further, the main ECU 70 communicates with the battery ECU 45 and the brake ECU 55 to exchange various signals and data with these ECUs.

  When the electric vehicle 20 travels, the main ECU 70 sets a target value Treq of torque required for traveling based on the accelerator opening Acc and the vehicle speed V, and a torque corresponding to the target value Treq is output from the motor MG. Thus, a torque command Tm * for the motor MG is set based on the target value Treq. Then, main ECU 70 controls switching of inverter 30 and boost converter 35 based on torque command Tm *. Further, the main ECU 70 mainly suppresses the occurrence of rattling noise due to switching of the tooth surface on the meshing side of the gear teeth in the differential gear 25 when the accelerator pedal 73 is depressed by the driver. The torque command value Tm * is slowly changed by, for example, an annealing process using a time constant so that the output torque of the motor MG gently approaches the target value Treq corresponding to the accelerator opening Acc and the vehicle speed V. The torque command value Tm * may be slowly changed by rate limit processing based on the upper and lower limit values of the change amount per predetermined time of the torque command value Tm *.

  Next, the operation of the electric vehicle 20 when the shift lever 71 is operated by the driver and the shift position is switched between the forward travel position such as the drive position and the reverse position will be described.

  While the system of the electric vehicle 20 is activated, the CPU of the main ECU 70 inputs the shift position SP from the shift position sensor 72 every predetermined time (for example, several mSec) as shown in FIG. 2 (step S100). It is determined whether or not the shift position SP has been switched from the forward travel position such as the drive position to the reverse position or from the reverse position to the forward travel position (step S110). When the main ECU 70 determines that the shift position SP is switched between the forward travel position and the reverse position, the main ECU 70 inputs the accelerator opening Acc from the accelerator pedal position sensor 74 every predetermined time (for example, several mSec) ( In step S120, it is determined whether or not the accelerator pedal 73 is depressed by the driver (step S130).

  If it is determined in step S130 that the accelerator pedal 73 is depressed by the driver, the main ECU 70 inputs the vehicle speed V detected by the vehicle speed sensor 75 (vehicle speed V when the accelerator pedal 73 is depressed) (step S140). Then, it is determined whether or not the absolute value of the input vehicle speed V is greater than zero (step S150). Here, as illustrated in FIG. 3, when the accelerator pedal 73 is released and the brake pedal 56 is depressed, the vehicle speed V is higher than zero and lower than the reference vehicle speed Vref. SP can be switched from the drive position (forward travel position) to the reverse position (see time t0 in FIG. 3). Then, after the shift position SP is switched, the driver depresses the accelerator pedal 73, and the electric vehicle 20 travels in a direction corresponding to the shift position SP before the switch due to inertia (in the forward direction in the example of FIG. 3). In this case (see time t1 in FIG. 3), it is determined in step S150 in FIG. 2 that the absolute value of the vehicle speed V is greater than zero.

  When it is determined in step S150 that the absolute value of the vehicle speed V is greater than zero, the main ECU 70 transmits a hydraulic brake operation command for operating the hydraulic brake device 50 to the brake ECU 55 (step S160). The brake ECU 55 that has received the hydraulic brake operation command provides a predetermined hydraulic pressure to each wheel cylinder 52 in order to apply braking torque to all wheels of the electric vehicle 20 including the drive wheels DW (in this embodiment, the same for all wheels). The brake actuator 53 is controlled so that (a constant value of hydraulic pressure) is supplied. The hydraulic pressure supplied to each wheel cylinder 52 when the hydraulic brake operation command is issued depends on the road surface gradient and the vehicle speed V when the accelerator pedal 73 is depressed by the driver after the shift position SP is switched. The driving wheel DW and the driven wheel may have different hydraulic pressure values.

  After the processing of step S160, the main ECU 70 inputs the vehicle speed V from the vehicle speed sensor 75 every predetermined time (for example, several mSec) (step S170), and determines whether or not the vehicle speed V has become zero (step S180). ). When it is determined in step S180 that braking torque is applied to all wheels including the drive wheels DW and the vehicle speed V has become zero, the main ECU 70 causes the brake ECU 55 to stop the hydraulic brake device 50 from operating. A release command is transmitted (step S190), and the series of processes in FIG. The brake ECU 55 that has received the hydraulic brake release command gradually reduces (gradually decreases) the braking torque applied to all the wheels of the electric vehicle 20 including the drive wheels DW until it reaches zero. The brake actuator 53 is controlled so that the cylinder pressure gradually decreases to zero.

  As a result of executing the series of processes as described above, after the shift position SP is switched between the forward traveling position and the reverse position, the driver performs an accelerator operation, and the electric vehicle 20 is shifted before the switching. When traveling in the direction corresponding to SP, braking torque is applied from the hydraulic brake device 50 to the drive wheels DW and the like in accordance with the depression of the accelerator pedal 73 by the driver (step S160 in FIG. 2). . As a result, compared with the case where the hydraulic brake device 50 is not operated (see the broken line in FIG. 3), the vehicle speed V is quickly reduced to zero (see times t2 and t2 ′ in FIG. 3), and the driver feels uncomfortable due to the backward movement. It can suppress giving.

  Further, when the accelerator pedal 73 is depressed by the driver after the shift position is switched between the forward travel position and the reverse travel position, the main ECU 70 causes the output torque of the motor MG to reach the accelerator opening Acc and the vehicle speed V. The torque command value Tm * is slowly changed so as to gradually approach the corresponding target value Treq. Accordingly, in the state where the braking torque is applied to the drive wheel DW farthest from the motor MG as the drive source in the torque transmission path, the output torque of the motor MG is gradually brought close to the target value Treq. It is possible to satisfactorily suppress the occurrence of rattling noise caused by switching of the gear tooth meshing side tooth surface in the differential gear 25 (gear mechanism) after switching.

  Further, when the vehicle speed V becomes zero (time t2 in FIG. 3), the braking torque applied from the hydraulic brake device 50 to the drive wheels DW and the like is gradually reduced until the output torque of the motor MG increases the accelerator opening. It gradually approaches the target value Treq corresponding to Acc. As a result, the running state of the electric vehicle 20 is smoothly shifted to a state corresponding to the shifted shift position SP, and the motor MG is driven as compared with the case where the hydraulic brake device 50 is not operated (see the broken line in FIG. 3). The timing at which the torque output to the wheel DW rises (timing that approximately matches the target value Treq) can be advanced (see times t3 and t3 ′ in FIG. 3).

  On the other hand, when it is determined in step S150 in FIG. 2 that the absolute value of the vehicle speed V is zero, the main ECU 70 once ends the processing in FIG. Also in this case, in the electric vehicle 20, when the accelerator pedal 73 is depressed by the driver, the torque command value Tm * so that the output torque of the motor MG gradually approaches the target value Treq corresponding to the accelerator opening Acc and the vehicle speed V. Therefore, after the shift position SP is switched, it is possible to satisfactorily suppress the occurrence of rattling noise caused by the change of the tooth surface on the meshing side of the gear teeth in the differential gear 25 (gear mechanism). Become.

  As described above, the main ECU 70 and the brake ECU 55 that are the control device of the electric vehicle 20 are configured such that the output torque of the motor MG (driving source) corresponds to the accelerator opening Acc when the accelerator operation is performed by the driver. The torque command value Tm * for the motor MG is slowly changed so as to gradually approach the value Treq. In addition, the main ECU 70 and the brake ECU 55 are operated in the direction corresponding to the shift position before the switching when the driver performs an accelerator operation after the shift position SP is switched between the forward travel position and the reverse position. The hydraulic brake device 50 is controlled so as to apply at least a braking torque to the drive wheels DW when proceeding to (steps S100 to S160 in FIG. 2). Further, the main ECU 70 and the brake ECU 55 control the hydraulic brake device 50 so as to gradually decrease the braking torque to zero in response to the braking torque being applied to at least the drive wheels DW and the vehicle speed V becoming zero. (Steps S170 to S190 in FIG. 2). As a result, in the electric vehicle 20, when the shift position SP is switched between the forward travel position and the reverse position, the rattling noise is generated in the differential gear 25 (gear mechanism) and the driver feels uncomfortable due to the reverse travel. It is possible to smoothly shift the traveling state of the electric vehicle 20 to a state corresponding to the shift position SP after switching while suppressing the application.

  The application target of the invention of the present disclosure is not limited to the electric vehicle 20 as described above. That is, the invention of the present disclosure may be applied to a hybrid vehicle having one or a plurality of motors, a two-motor hybrid vehicle having a planetary gear for power distribution, a series hybrid vehicle, or the like. A hybrid vehicle to which the invention of the present disclosure is applied may have a transmission that shifts power from a drive source including an electric motor and transmits the power to a differential gear. It may have an electric motor connected to the output shaft of the machine. Furthermore, the control device according to the present disclosure can be used as a drive source if it can slowly change the output torque of the drive source so that it gradually approaches a target value corresponding to the accelerator operation amount when the driver performs an accelerator operation. The present invention may be applied to a vehicle that has only an engine and has a transmission that shifts power from the engine as a gear mechanism and a differential gear that is coupled to an output shaft of the transmission.

  And the invention of this indication is not limited to the above-mentioned embodiment at all, and it cannot be overemphasized that various changes can be made within the range of the extension of this indication. Furthermore, the above-described embodiment is merely a specific form of the invention described in the Summary of Invention column, and does not limit the elements of the invention described in the Summary of Invention column.

  The invention of the present disclosure can be used in the vehicle manufacturing industry.

  20 electric vehicle, 25 differential gear, 30 inverter, 35 step-up converter, 40 battery, 45 battery electronic control unit (battery ECU), 50 hydraulic brake device, 51 master cylinder, 52 wheel cylinder, 53 brake actuator, 55 brake electronics Control unit (brake ECU), 56 brake pedal, 57 brake pedal stroke sensor, 70 main electronic control unit (main ECU), 71 shift lever, 72 shift position sensor, 73 accelerator pedal, 74 accelerator pedal position sensor, 75 vehicle speed sensor, DW drive wheel, MG motor.

Claims (1)

A vehicle control device having a drive source connected to a drive wheel via a gear mechanism, and a hydraulic brake device capable of applying at least a braking torque to the drive wheel regardless of whether or not a driver performs a brake operation. In the control device that slowly changes the output torque of the drive source so as to gradually approach the target value corresponding to the accelerator operation amount when the driver performs the accelerator operation,
After the shift position is switched between the forward travel position and the reverse travel position, at least the drive when the driver performs an accelerator operation and the vehicle travels in a direction corresponding to the shift position before the switch Braking start means for controlling the hydraulic brake device to apply the braking torque to a wheel;
Braking release means for controlling the hydraulic brake device so as to gradually reduce the braking torque to zero in response to the braking torque being applied to at least the driving wheel and the vehicle speed becoming zero; and
A vehicle control apparatus comprising:

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