JP2016107813A - Hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve driving performance exerted upon reverse running.SOLUTION: A hybrid vehicle comprises an engine, a first motor, a planetary gear mechanism, a second motor, a battery, and an air pressure adjustment device. The planetary gear mechanism is configured in such a way that a sun gear is coupled to a rotation shaft of the first motor, a carrier is coupled to an output shaft of the engine, and a ring gear is coupled to a drive axle which is coupled to a driving wheel. The air pressure adjustment device adjusts inflation pressure of a tire attached to the driving wheel. In such a hybrid vehicle, when driving force is insufficient (S120-S150) during reverse running, tire inflation pressure is reduced relative to reference pressure to reduce a tire effective radius (S160). Driving force of the driving wheel therefore can be increased, and driving performance during reverse running can be further increased.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a hybrid vehicle, and more particularly, to a hybrid vehicle including an engine, a first motor, a planetary gear mechanism, a second motor, and a battery.

  Conventionally, in this type of hybrid vehicle, a carrier, a sun gear, and a ring gear are connected to three axes of an engine, a first motor, an output shaft of the engine, a rotating shaft of the first motor, and a drive shaft connected to a drive wheel. A planetary gear mechanism, a second motor that can output power to the drive shaft, and a battery that exchanges power with the first motor and the second motor have been proposed (for example, see Patent Document 1). In this hybrid vehicle, the three rotating elements of the planetary gear mechanism are connected in the order of the rotating shaft of the first motor, the output shaft of the engine, and the driving shaft on the alignment chart. For this reason, the planetary gear mechanism transmits power from the engine to the drive shaft as power in the forward direction by having a reaction force of torque with the first motor. Therefore, when reverse running is requested, the engine operation is basically stopped, and the second motor is driven in reverse rotation.

JP 2010-284991 A

  As described above, in the hybrid vehicle described above, the engine cannot be used as a power source during reverse traveling. For example, when traveling on a steep uphill road during reverse traveling or overcoming a step during reverse traveling. For example, the required driving force may be insufficient. Although it is conceivable to use a motor having a large maximum driving force as the second motor, the motor may be increased in size or the efficiency at low load may deteriorate.

  The main purpose of the hybrid vehicle of the present invention is to further improve the running performance during reverse running.

  The hybrid vehicle of the present invention employs the following means in order to achieve the main object described above.

The hybrid vehicle of the present invention
Three axes of an engine, a first motor that inputs and outputs power, an output shaft of the engine, a rotating shaft of the first motor, and a driving shaft connected to a driving wheel are the rotating shaft and the output on an alignment chart. A planetary gear mechanism connected to three rotating elements so as to be arranged in the order of the shaft and the drive shaft, and transmitting the power from the engine to the drive shaft as power in the forward rotation direction with the output of power from the first motor A hybrid vehicle comprising: a second motor capable of outputting power in both forward and reverse rotation directions to the drive shaft; and a battery that exchanges power with the first motor and the second motor,
Air pressure adjusting means for adjusting the air pressure of a tire mounted on the drive wheel;
The air pressure adjusting means is configured to reduce the tire air pressure when the driving force output to the drive shaft is insufficient during the reverse running when the reverse running is performed by outputting the power in the reverse rotation direction from the second motor. Control means for controlling
It is a summary to provide.

  In the hybrid vehicle of the present invention, the rotating shaft of the first motor, the output shaft of the engine, and the driving shaft connected to the driving wheels are connected to the three rotating elements of the planetary gear mechanism in the order of the alignment chart. Therefore, the planetary gear mechanism can transmit power from the engine as power in the forward direction to the drive shaft, but cannot transmit power in the reverse direction to the drive shaft. Accordingly, since reverse traveling cannot use an engine as a power source for traveling, the maximum driving force that can be output is smaller than forward traveling. In the hybrid vehicle of the present invention, when the driving force output to the driving shaft is insufficient during reverse traveling, the tire diameter is reduced by reducing the air pressure of the tire mounted on the driving wheel. Since the force (driving force) acting on the ground contact surface of the tire is inversely proportional to the tire diameter, the driving force can be increased by reducing the tire diameter, and the running performance during reverse running can be further improved.

1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 as an embodiment of the present invention. It is explanatory drawing explaining the dynamic relationship of the rotation speed and torque in the rotation element of the planetary gear 30 at the time of reverse running using a nomograph. 3 is a flowchart showing an example of an air pressure adjustment control routine executed by an HVECU 70.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20 as an embodiment of the present invention. As illustrated, the hybrid vehicle 20 of the embodiment includes an engine 22, a planetary gear 30, a motor MG1, a motor MG2, inverters 41 and 42, a battery 50, an air pressure adjusting device 60, and a hybrid electronic control unit. (Hereinafter referred to as HVECU) 70.

  The engine 22 is configured as an internal combustion engine that outputs power using gasoline, light oil, or the like as fuel, and is operated and controlled by an engine electronic control unit (hereinafter referred to as engine ECU) 24.

  Although not shown, the engine ECU 24 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . Signals from various sensors necessary for controlling the operation of the engine 22 are input to the engine ECU 24 via an input port. Various control signals for controlling the operation of the engine 22 are output from the engine ECU 24 through an output port. The engine ECU 24 calculates the rotational speed Ne of the engine 22 based on a signal from a crank position sensor (not shown) attached to the crankshaft 26 of the engine 22.

  The planetary gear 30 is configured as a single pinion type planetary gear mechanism. A drive shaft 36 connected to the rotor of the motor MG1, the crankshaft 26 of the engine 22, and the drive wheels 38a and 38b via the differential gear 37 is connected to the sun gear, the carrier, and the ring gear of the planetary gear 30, respectively.

  The motor MG1 is configured as a synchronous generator motor, and the rotor is connected to the sun gear of the planetary gear 30 as described above. The motor MG2 is configured as a synchronous generator motor, and the rotor is connected to the drive shaft 36 as described above. Motors MG1 and MG2 convert DC power from battery 50 into three-phase AC power by switching control of switching elements (not shown) of inverters 41 and 42 by motor electronic control unit (hereinafter referred to as motor ECU) 40. It is driven by being supplied.

  Although not shown, the motor ECU 40 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . The motor ECU 40 has signals necessary for driving and controlling the motors MG1 and MG2, for example, rotational positions θm1 and θm2 from a rotational position detection sensor (not shown) for detecting the rotational position of the rotor of the motors MG1 and MG2, not shown. A phase current applied to the motors MG1 and MG2 detected by the current sensor is input via the input port. Further, the motor ECU 40 outputs a switching control signal to a switching element (not shown) of the inverters 41 and 42 through an output port. The motor ECU 40 is in communication with the HVECU 70, controls the driving of the motors MG1, MG2 by a control signal from the HVECU 70, and outputs data related to the operating state of the motors MG1, MG2 to the HVECU 70 as necessary. The motor ECU 40 also calculates the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 based on the rotational positions θm1 and θm2 of the rotors of the motors MG1 and MG2 from the rotational position detection sensor.

  The battery 50 is configured as a lithium ion secondary battery, for example, and exchanges electric power with the motors MG1 and MG2 via the inverters 41 and 42. The battery 50 is managed by a battery electronic control unit (hereinafter referred to as a battery ECU) 52. Although not shown, the battery ECU 52 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . The battery ECU 52 receives signals necessary for managing the battery 50, for example, an inter-terminal voltage Vb from a voltage sensor (not shown) installed between the terminals of the battery 50 and a power line connected to the output terminal of the battery 50. The charging / discharging current Ib from the attached current sensor (not shown), the battery temperature Tb from the temperature sensor (not shown) attached to the battery 50, and the like are input. Send to. Further, in order to manage the battery 50, the battery ECU 52 is a power storage that is a ratio of the capacity of the electric power that can be discharged from the battery 50 at that time based on the integrated value of the charge / discharge current Ib detected by the current sensor. The ratio SOC is calculated, and the input / output limits Win and Wout, which are the maximum allowable power that may charge / discharge the battery 50, are calculated based on the calculated storage ratio SOC and the battery temperature Tb.

  The air pressure adjusting device 60 is mounted on the drive wheels 38a and 38b (wheels), respectively, and is configured to be able to individually adjust the air pressure of the tires 39a and 39b attached to the drive wheels 38a and 38b. The air pressure adjusting device 60 includes a pressure sensor 62 that detects the air pressure of the tires 39a and 39b, a pressure pump 64 that fills the tires 39a and 39b with pressurized air, and an electromagnetic valve that is attached to a communication hole of the tires 39a and 39b. 66. The air pressure adjusting device 60 can increase the air pressure of the tires 39a and 39b by closing the electromagnetic valve 66 and driving the pressurizing pump 64, and stops driving the pressurizing pump 64 and the electromagnetic valve 66. By opening the valve, the air pressure of the tires 39a and 39b can be reduced. The pressurizing pump 64 and the electromagnetic valve 66 mounted on the drive wheels 38a and 38b (rotating system) are electrically connected to the battery 50 mounted on the vehicle body (stationary system) (not shown) via a slip ring, It is driven by receiving power from the battery 50.

  Although not shown, the HVECU 70 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. The HVECU 70 includes an ignition signal from the ignition switch 80, a shift position SP from the shift position sensor 82 that detects the operation position of the shift lever 81, and an accelerator opening from the accelerator pedal position sensor 84 that detects the amount of depression of the accelerator pedal 83. Acc, the brake pedal position BP from the brake pedal position sensor 86 that detects the depression amount of the brake pedal 85, the vehicle speed V from the vehicle speed sensor 88, the air pressure of the tires 39a and 39b from the pressure sensor 62, and the like are input via the input port. Has been. Further, from the HVECU 70, a drive signal to the pressurizing pump 64, a drive signal to the electromagnetic valve 66, and the like are output via the output port. Here, as a shift position SP of the shift lever 81, a parking position (P position) used at the time of parking, a reverse position (R position) for reverse travel, a neutral position (N position) for neutral travel, and a normal drive position for forward travel (D position) etc. are prepared. Further, the vehicle speed sensor 88 detects the vehicle speed in the forward direction as positive when the shift position SP is the drive position (D position), and detects the vehicle speed in the reverse direction as positive when the shift position SP is in the reverse position (R position). Further, as described above, the air pressure adjusting device 60 (the pressure sensor 62, the pressurizing pump 64, and the electromagnetic valve 66) is attached to the drive wheels 38a and 38b (rotating system). The HVECU 70 attached to the vehicle body (stationary system) is electrically connected to the air pressure adjusting device 60 via a slip ring (not shown), and exchanges signals with the air pressure adjusting device 60 via the slip ring. The HVECU 70 is communicably connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52, and exchanges various control signals and data with the engine ECU 24, the motor ECU 40, and the battery ECU 52.

The hybrid vehicle 20 of the embodiment configured in this way calculates the required torque Tr * to be output to the drive shaft 36 based on the accelerator opening Acc and the vehicle speed V corresponding to the depression amount of the accelerator pedal 83 by the driver. The operation of the engine 22, the motor MG1, and the motor MG2 is controlled so that the required power corresponding to the required torque Tr * is output to the drive shaft 36. As the operation control of the engine 22, the motor MG1, and the motor MG2, there are the following (1) to (3). The torque conversion operation mode (1) and the charge / discharge operation mode (2) both control the engine 22 and the motors MG1, MG2 so that the required power is output to the drive shaft 36 with the operation of the engine 22. Since these are modes and there is no substantial difference in control, hereinafter, both are collectively referred to as an engine operation mode (hybrid mode).
(1) Torque conversion operation mode: The operation of the engine 22 is controlled so that power corresponding to the required power is output from the engine 22, and all of the power output from the engine 22 is torqued by the planetary gear 30, the motor MG1, and the motor MG2. An operation mode in which the motor MG1 and the motor MG2 are drive-controlled so that they are converted and output to the drive shaft 36.
(2) Charging / discharging operation mode: The engine 22 is operated and controlled so that the power corresponding to the sum of the required power and the power required for charging / discharging the battery 50 is output from the engine 22 and the battery 50 is charged / discharged. Operation for driving and controlling the motor MG1 and the motor MG2 so that all or part of the power output from the engine 22 is output to the drive shaft 36 with the torque conversion by the planetary gear 30, the motor MG1, and the motor MG2. mode.
(3) Motor operation mode (EV mode): An operation mode in which the operation of the engine 22 is stopped and operation is controlled so that power corresponding to the required power from the motor MG2 is output to the drive shaft 36.

  Specifically, the engine operation mode (hybrid mode) is controlled as follows. That is, the HVECU 70 is obtained by multiplying the required torque Tr * set from the accelerator opening Acc and the vehicle speed V by the rotation speed Nr of the drive shaft 36 (for example, the rotation speed Nm2 of the motor MG2 and the vehicle speed V by a conversion factor). The travel power Pdrv * required for travel is calculated by multiplying Subsequently, the engine required for the engine 22 by subtracting the charge / discharge required power Pb * (positive value when discharging from the battery 50) based on the storage ratio SOC of the battery 50 from the calculated traveling power Pdrv *. The required power Pe * is set. Then, a target operating point (operating point) of the engine 22 determined by the target rotational speed Ne * and the target torque Te * is set based on the engine required power Pe *. Here, the target operating point (target rotational speed Ne * and target torque Te *) of the engine 22 is an operation line (fuel consumption operation line) of the engine 22 that can output the engine required power Pe * from the engine 22 efficiently. And the engine required power Pe *. Next, the torque command Tm1 * of the motor MG1 is set by the rotational speed feedback control so that the rotational speed Ne of the engine 22 becomes the target rotational speed Ne * within the range of the input / output limits Win and Wout of the battery 50. At the same time, the torque command Tm2 * of the motor MG2 is set so that the required torque Tr * is output to the drive shaft 36. Then, the set target rotational speed Ne * and target torque Te * of the engine 22 are transmitted to the engine ECU 24, and torque commands Tm1 * and Tm2 * of the motors MG1 and MG2 are transmitted to the motor ECU 40. The engine ECU 24 that has received the target rotational speed Ne * and the target torque Te *, controls the intake air amount, fuel injection control, and ignition of the engine 22 so that the engine 22 is operated by the target rotational speed Ne * and the target torque Te *. Control and so on. The motor ECU 40 that has received the torque commands Tm1 * and Tm2 * performs switching control of the switching elements of the inverters 41 and 42 so that the motors MG1 and MG2 are driven by the torque commands Tm1 * and Tm2 *.

  The motor operation mode is controlled as follows. That is, the HVECU 70 sets the required torque Tr * within a range that does not exceed the maximum torque of the motor MG2 based on the accelerator opening Acc and the vehicle speed V. Then, the torque command Tm2 * of the motor MG2 is set so that the required torque Tr * is output to the drive shaft 36 within the range of the input / output limits Win and Wout of the battery 50, and the torque command Tm2 * is transmitted to the motor ECU 40. . Receiving the torque command Tm2 *, the motor ECU 40 performs switching control of the switching element of the inverter 42 so that the motor MG2 is driven by the torque command Tm2 *.

  When the shift position SP is operated to the R (reverse) position and reverse travel is requested, operation control in the motor operation mode is performed. FIG. 2 is an explanatory diagram for explaining the mechanical relationship between the rotation speed and torque in the rotating element of the planetary gear 30 during reverse running, using a nomograph. In the figure, the left S-axis indicates the rotational speed of the sun gear, which is the rotational speed of the motor MG1, the central C-axis indicates the rotational speed of the carrier, which is the rotational speed of the engine 22, and the right R-axis indicates the drive shaft. The rotation speed of the ring gear which is 36 rotation speed is shown. A thick arrow on the R axis indicates a negative torque Tm2 output from the motor MG2 during reverse traveling. As shown in the figure, the planetary gear 30 is connected so that three rotating elements are arranged in the order of the rotating shaft of the motor MG1, the crankshaft 26 of the engine 22, and the driving shaft 36 on the alignment chart. By having a reaction force, the power from the engine 22 is transmitted to the drive shaft 36. Therefore, the torque transmitted from the engine 22 to the drive shaft 36 via the planetary gear 30 is a positive torque, and the negative torque Tm2 output from the motor MG2 during reverse travel is a torque transmitted from the engine 22 to the drive shaft 36. Is offset by Therefore, the control in the motor operation mode during reverse traveling is basically performed by stopping the operation of the engine 22 and outputting the negative torque Tm2 from the motor MG2 to the drive shaft 38. As described above, in reverse traveling, the engine 22 cannot be used as a power source for traveling, and therefore the maximum torque that can be output to the drive shaft 36 is smaller than in forward traveling.

  Next, the operation of the hybrid vehicle 20 of the embodiment thus configured, particularly the operation during reverse running will be described. FIG. 3 is a flowchart showing an example of an air pressure adjustment control routine executed by the CPU 72 of the HVECU 70. This routine is repeatedly executed every predetermined time (for example, every several msec).

  When the air pressure adjustment control routine is executed, the CPU 72 of the HVECU 70 first inputs data necessary for control such as an ignition signal, shift position SP, accelerator opening degree Acc, vehicle speed V (step S100). Subsequently, it is determined whether or not the decompression flag F is OFF (step S110). Here, the decompression flag F is turned OFF in step S230, which will be described later, when the air pressure of the tires 39a, 39b attached to the drive wheels 38a, 38b is set to the standard pressure, and the air pressure of the tires 39a, 39b is set from the standard pressure. Is also turned on in step S160 described later when the pressure is reduced.

  If it is determined that the decompression flag F is OFF, it is determined whether or not the shift position SP is the R (reverse) position (step S120), and whether or not the vehicle speed V is less than the first vehicle speed (for example, 1 km / h) (step S130). ), Whether or not the accelerator opening Acc is larger than the first opening (for example, 90%) is determined (step S140). When all of the determinations in steps S120 to S140 are affirmative determinations, it is determined whether or not the state continues for a predetermined time T1 (for example, 3 seconds) (S150). The determinations in steps S120 to S150 are not easy for the vehicle to start despite the fact that the accelerator pedal 83 is relatively depressed, such as when driving on a steep uphill road in reverse or over a step. This is to determine the state that has occurred. When a positive determination is made in any of steps S120 to S150, it is determined that the driving force output to the drive shaft 36 is insufficient, so that the air pressure of the tires 39a and 39b is reduced below the standard pressure. Pressure reduction control for controlling the pressure pump 64 and the electromagnetic valve 66 is performed (step S160). Then, the decompression flag F is set to ON (step S170), and the air pressure adjustment control routine is ended. The pressure reduction control is control for reducing the air pressure of the tires 39a and 39b from the standard pressure so that the effective tire radius is reduced. Here, the force (driving force) F acting on the ground contact surfaces of the tires 39a and 39b is expressed by the following formula (Td) as the torque output to the drive shaft 36, γ as the final reduction ratio, and rd as the effective tire radius. 1).

  F = Td · γ / rd (1)

  As shown in Expression (1), the driving force F is inversely proportional to the tire effective radius rd, and therefore increases as the tire effective radius rd decreases. Therefore, by reducing the air pressure of the tires 39a and 39b and reducing the effective tire radius rd, the driving force F can be increased and the running performance during reverse running can be improved. When any of steps S120 to S140 is a negative determination, or when any of steps S120 to S140 is a positive determination and the state has not continued for a predetermined time T1 or more, the pressure reduction control. The air amount adjustment control routine is terminated without performing.

  If it is determined in step S110 that the decompression flag F is ON, whether or not the shift position SP is a position other than the R position (D position, N position, P position) (step S180), and the vehicle speed V is It is determined whether or not it is greater than the second vehicle speed (for example, 5 km / h) (step S190). Further, it is determined whether or not the accelerator opening Acc is less than a second opening (for example, 50%) (step S200) and whether or not the ignition switch 80 is turned off (step S210). The second vehicle speed and the second opening are set larger than the first vehicle speed and the first opening, respectively, so as to prevent frequent switching of the air pressure control state. If any of the determinations in steps S180 to S210 is negative, the pressure reduction control is maintained and the air pressure adjustment control routine is terminated. On the other hand, if any of steps S180 to S210 is affirmative, it is determined that the output of a large driving force is no longer necessary, and the pressure pump 64 and the solenoid valve are set so that the air pressure of the tires 39a and 39b returns to the standard pressure. 66 is performed (step S220). Then, the decompression flag F is turned OFF (step S230), and the air pressure adjustment control routine is ended.

  The hybrid vehicle 20 of the present embodiment described above is provided with the air pressure adjusting device 60 that adjusts the air pressure of the tires 39a and 39b attached to the drive wheels 38a and 38b, respectively. When the driving force is insufficient during reverse running, the tire effective radius is reduced by performing pressure reduction control for reducing the air pressure of the tires 39a and 39b below the standard pressure. Thereby, the driving force of the driving wheels 38a and 38b can be increased, and the running performance during reverse running can be further improved. Further, since the pressure reduction control is not executed at the time of forward traveling or at a high vehicle speed, the tires 39a and 39b can be prevented from being adversely affected and the behavior of the vehicle can be prevented from becoming unstable.

  In the hybrid vehicle 20 of the embodiment, it is determined whether or not the driving force output to the drive shaft 36 is insufficient based on the accelerator opening Acc and the vehicle speed V. However, the present invention is not limited to this. Instead, for example, the road surface gradient may be detected, and it may be determined that the driving force output to the drive shaft 36 is insufficient when the detected road surface gradient is an ascending gradient equal to or higher than a predetermined gradient.

  As mentioned above, although the form for implementing this invention was demonstrated using the Example, this invention is not limited at all to such an Example, In the range which does not deviate from the summary of this invention, it is with various forms. Of course, it can be implemented.

  The present invention can be used in the manufacturing industry of hybrid vehicles.

  20 hybrid vehicle, 22 engine, 24 electronic control unit for engine (engine ECU), 26 crankshaft, 30 planetary gear, 36 drive shaft, 37 differential gear, 38a, 38b drive wheel, 39a, 39b tire, 40 electronic control unit for motor (Motor ECU), 41, 42 inverter, 50 battery, 52 battery electronic control unit (battery ECU), 60 air pressure adjusting device, 62 pressure sensor, 64 pressure pump, 66 solenoid valve, 70 hybrid electronic control unit (HVECU) ), 80 ignition switch, 81 shift lever, 82 shift position sensor, 83 accelerator pedal, 84 accelerator pedal position sensor, 85 brake pedal, 86 brake pedal position Nsensa, 88 vehicle speed sensor, MG1, MG2 motor.

Claims (1)

Three axes of an engine, a first motor that inputs and outputs power, an output shaft of the engine, a rotating shaft of the first motor, and a driving shaft connected to a driving wheel are the rotating shaft and the output on an alignment chart. A planetary gear mechanism connected to three rotating elements so as to be arranged in the order of the shaft and the drive shaft, and transmitting the power from the engine to the drive shaft as power in the forward rotation direction with the output of power from the first motor A hybrid vehicle comprising: a second motor capable of outputting power in both forward and reverse rotation directions to the drive shaft; and a battery that exchanges power with the first motor and the second motor,
Air pressure adjusting means for adjusting the air pressure of a tire mounted on the drive wheel;
The air pressure adjusting means is configured to reduce the tire air pressure when the driving force output to the drive shaft is insufficient during the reverse running when the reverse running is performed by outputting the power in the reverse rotation direction from the second motor. Control means for controlling
A hybrid vehicle comprising:

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