JP2009126253A - Hybrid vehicle and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress remarkable reduction of residual capacity of an electric storage device such as a secondary battery, and to improve mileage in part, when turning off an accelerator in the middle of traveling in a power mode. <P>SOLUTION: When the accelerator is turned off in the middle of the traveling in a state that the power mode is selected, fuel supply to an engine is stopped (fuel-cut) until a vehicle speed V becomes less than a threshold value Vfc, and motoring is performed by a motor MG1 such that the engine rotates at a lower limit engine speed Nemin based on the vehicle speed V (S140, S150, S210-S240). On and after the vehicle speed V becomes less than the threshold value Vfc, the fuel supply to the engine is resumed to perform self-operation of the engine at the lower limit engine speed Nemin based on the vehicle speed V (S160, S170, S210-S240). Thereby, motive power can be rapidly output from the engine when requesting acceleration, and the mileage of a vehicle can be improved, so that the remarkable reduction of the residual capacity (SOC) of the battery can be suppressed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hybrid vehicle and a control method thereof.

  Conventionally, as this type of vehicle, an electric motor capable of motoring an internal combustion engine has been proposed, and an internal combustion engine in which fuel supply has been stopped until the vehicle stops when the vehicle is decelerated is motored by the electric motor. (For example, refer to Patent Document 1). In this vehicle, by motoring the internal combustion engine, when the accelerator pedal is depressed, it is possible to quickly output from the internal combustion engine.

JP-A-10-339182

  In a hybrid vehicle equipped with an internal combustion engine and an electric motor capable of outputting traveling power, when the accelerator is turned off while the internal combustion engine is being operated during traveling, the internal combustion engine is idled in order to improve the fuel consumption of the vehicle. It is common to operate or stop the operation of the internal combustion engine. On the other hand, in order to respond to the driver's desire to drive with good acceleration response, a mode changeover switch that switches between the normal driving mode that prioritizes the fuel consumption of the vehicle and the power priority mode that can output the power quickly and drive In the power priority mode, in order to quickly output power from the internal combustion engine, the internal combustion engine is operated at a relatively high rotational speed corresponding to the vehicle speed even when the accelerator is turned off during traveling. It is controlled so that At this time, if the internal combustion engine is operated with the fuel supply to the internal combustion engine in order to make the rotational speed of the internal combustion engine relatively high, the fuel consumption is greatly deteriorated, and the fuel supply to the internal combustion engine is reduced. When the motor is stopped and motored by the motor, the remaining battery capacity may be significantly reduced.

  The hybrid vehicle and the control method thereof according to the present invention suppresses a significant decrease in the remaining capacity of a power storage device such as a secondary battery when the accelerator is turned off while traveling in the power priority mode, and provides a certain level of fuel consumption. The main purpose is to improve the quality.

  The hybrid vehicle of the present invention and its control method employ the following means in order to achieve the main object described above.

The hybrid vehicle of the present invention
An internal combustion engine;
Connected to the drive shaft connected to the wheels and connected to the output shaft of the internal combustion engine so as to be rotatable independently of the drive shaft, and to the drive shaft and the output shaft with input and output of electric power and power Electric power input / output means for inputting / outputting power;
An electric motor that inputs and outputs driving power;
A power storage means for exchanging power with the electric power drive input / output means and the electric motor;
Vehicle speed detection means for detecting the vehicle speed;
A mode changeover switch that switches between a normal driving mode for driving with relatively high priority on fuel consumption and a power priority mode for reducing the fuel consumption as compared with the normal driving mode but capable of driving by quickly outputting power. When,
Lower limit speed setting means for setting a lower limit speed of the internal combustion engine based on the detected vehicle speed when the power priority mode is set by the mode changeover switch;
Required driving force setting means for setting required driving force required for traveling;
When the accelerator is turned off while traveling with the power priority mode set by the mode switch, the fuel supply to the internal combustion engine is stopped when the detected vehicle speed exceeds a predetermined vehicle speed. The internal combustion engine, the electric power drive input / output means, and the electric motor are controlled so that the internal combustion engine rotates at the set lower limit rotation speed and travels with the set required driving force, and the detected vehicle speed is Control for controlling the internal combustion engine, the power power input / output means, and the electric motor so that the internal combustion engine operates independently at the set lower limit rotational speed and travels with the set required driving force when the vehicle speed is lower than a predetermined vehicle speed. Means,
It is a summary to provide.

  In the hybrid vehicle of the present invention, when the accelerator is turned off while the vehicle is running with the power priority mode set by the mode switch, the fuel supply to the internal combustion engine is stopped when the vehicle speed is higher than the predetermined vehicle speed. The internal combustion engine, the power drive input / output means, and the electric motor are controlled so that the internal combustion engine rotates at the lower limit rotational speed set based on the vehicle speed and travels with the required driving force required for traveling. That is, the internal combustion engine is motored by the power drive input / output means. Thus, power can be output from the internal combustion engine quickly when acceleration is requested, and the fuel efficiency of the vehicle can be improved. On the other hand, when the vehicle speed is less than the predetermined vehicle speed, the internal combustion engine, the electric power drive input / output means, and the electric motor are controlled so that the internal combustion engine operates independently at the lower limit rotational speed and travels with the required driving force. As a result, power can be output from the internal combustion engine quickly even when the vehicle speed is less than the predetermined vehicle speed, and the power storage capacity (remaining capacity) of the power storage means can be prevented from significantly decreasing.

  In such a hybrid vehicle of the present invention, the control means travels with the set required driving force in a state where the operation of the internal combustion engine is stopped when the detected vehicle speed is less than the stop vehicle speed smaller than the predetermined vehicle speed. It may be a means for controlling the internal combustion engine, the power drive input / output means and the electric motor. If it carries out like this, it can drive | work with the operation stop of an internal combustion engine.

  In the hybrid vehicle of the present invention, the lower limit rotational speed setting means may be a means for setting the lower limit rotational speed so that the lower the rotational speed, the higher the detected vehicle speed. If it carries out like this, the power according to the vehicle speed can be rapidly output from an internal combustion engine.

  Further, in the hybrid vehicle of the present invention, the control means may be means for controlling using a vehicle speed having hysteresis as the predetermined vehicle speed. In this way, it is possible to suppress hunting between motoring and independent operation of the internal combustion engine.

  Further, in the hybrid vehicle of the present invention, the power power input / output means is connected to three axes of a generator capable of inputting / outputting power, an output shaft of the internal combustion engine, the drive shaft, and a rotating shaft of the generator. And a three-axis power input / output means for inputting / outputting power to / from the remaining shafts based on power input / output to / from any two of the three axes.

The hybrid vehicle control method of the present invention includes:
Connected to the internal combustion engine and a drive shaft connected to the wheels and connected to the output shaft of the internal combustion engine so as to be rotatable independently of the drive shaft, the drive shaft and the output with input and output of electric power and power Electric power input / output means for inputting / outputting power to / from the shaft, an electric motor for inputting / outputting driving power, an electric power input / output means, and an electric storage means for exchanging electric power with the electric motor, and comparatively prioritizing fuel consumption And a mode changeover switch for switching and setting a normal driving mode for driving and a power priority mode capable of driving by quickly outputting power while reducing fuel consumption compared to the normal driving mode A vehicle control method,
When the accelerator is turned off while the power priority mode is set by the mode changeover switch and the vehicle speed is equal to or higher than a predetermined vehicle speed, the internal combustion engine is stopped while the fuel supply to the internal combustion engine is stopped. The internal combustion engine, the power power input / output means, and the electric motor are controlled to rotate at the lower limit rotational speed set based on the vehicle and to drive with the required driving force required for traveling, and the vehicle speed is less than the predetermined vehicle speed. The gist of the invention is that the internal combustion engine, the electric power drive input / output means, and the electric motor are controlled so that the internal combustion engine operates independently at the lower limit rotational speed and travels with the required driving force.

  In the hybrid vehicle control method of the present invention, the fuel supply to the internal combustion engine is stopped when the vehicle speed is equal to or higher than the predetermined vehicle speed when the accelerator is turned off while the power priority mode is set by the mode switch. In this state, the internal combustion engine, the electric power drive input / output means, and the electric motor are controlled so that the internal combustion engine rotates at the lower limit rotational speed set based on the vehicle speed and travels with the required driving force required for traveling. That is, the internal combustion engine is motored by the power drive input / output means. Thus, power can be output from the internal combustion engine quickly when acceleration is requested, and the fuel efficiency of the vehicle can be improved. On the other hand, when the vehicle speed is less than the predetermined vehicle speed, the internal combustion engine, the electric power drive input / output means, and the electric motor are controlled so that the internal combustion engine operates independently at the lower limit rotational speed and travels with the required driving force. As a result, power can be output from the internal combustion engine quickly even when the vehicle speed is less than the predetermined vehicle speed, and the power storage capacity (remaining capacity) of the power storage means can be prevented from significantly decreasing.

  Next, the best mode for carrying out the present invention will be described using examples.

  FIG. 1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 as an embodiment of the present invention. As shown in the figure, the hybrid vehicle 20 of the embodiment includes an engine 22, a three-shaft power distribution / integration mechanism 30 connected to a crankshaft 26 as an output shaft of the engine 22 via a damper 28, and power distribution / integration. A motor MG1 capable of generating electricity connected to the mechanism 30, a reduction gear 35 attached to a ring gear shaft 32a as a drive shaft connected to the power distribution and integration mechanism 30, a motor MG2 connected to the reduction gear 35, And a hybrid electronic control unit 70 for controlling the entire vehicle.

  The engine 22 is an internal combustion engine that outputs power using a hydrocarbon-based fuel such as gasoline or light oil, and an engine electronic control unit (hereinafter referred to as an engine ECU) that receives signals from various sensors that detect the operating state of the engine 22. ) 24 is subjected to operation control such as fuel injection control, ignition control, intake air amount adjustment control and the like. The engine ECU 24 receives signals from various sensors (not shown) such as a crank position sensor attached to the crankshaft 26. Further, the engine ECU 24 communicates with the hybrid electronic control unit 70, controls the operation of the engine 22 by a control signal from the hybrid electronic control unit 70, and transmits data on the operation state of the engine 22 as necessary for the hybrid. Output to the electronic control unit 70.

  The power distribution and integration mechanism 30 includes an external gear sun gear 31, an internal gear ring gear 32 arranged concentrically with the sun gear 31, a plurality of pinion gears 33 that mesh with the sun gear 31 and mesh with the ring gear 32, A planetary gear mechanism is provided that includes a carrier 34 that holds a plurality of pinion gears 33 so as to rotate and revolve, and that performs differential action using the sun gear 31, the ring gear 32, and the carrier 34 as rotational elements. In the power distribution and integration mechanism 30, the crankshaft 26 of the engine 22 is connected to the carrier 34, the motor MG1 is connected to the sun gear 31, and the reduction gear 35 is connected to the ring gear 32 via the ring gear shaft 32a. When functioning as a generator, power from the engine 22 input from the carrier 34 is distributed according to the gear ratio between the sun gear 31 side and the ring gear 32 side, and when the motor MG1 functions as an electric motor, the engine input from the carrier 34 The power from 22 and the power from the motor MG1 input from the sun gear 31 are integrated and output to the ring gear 32 side. The power output to the ring gear 32 is finally output from the ring gear shaft 32a to the drive wheels 63a and 63b of the vehicle via the gear mechanism 60 and the differential gear 62.

  The motor MG1 and the motor MG2 are both configured as well-known synchronous generator motors that can be driven as generators and can be driven as motors, and exchange power with the battery 50 via inverters 41 and 42. The power line 54 connecting the inverters 41 and 42 and the battery 50 is configured as a positive electrode bus and a negative electrode bus shared by the inverters 41 and 42, and the electric power generated by one of the motors MG1 and MG2 It can be consumed by a motor. Therefore, battery 50 is charged / discharged by electric power generated from one of motors MG1 and MG2 or insufficient electric power. If the balance of electric power is balanced by the motors MG1 and MG2, the battery 50 is not charged / discharged. The motors MG1 and MG2 are both driven and controlled by a motor electronic control unit (hereinafter referred to as a motor ECU) 40. The motor ECU 40 receives signals necessary for driving and controlling the motors MG1 and MG2, for example, the rotational positions of the rotors of the motors MG1 and MG2 from the rotational position detection sensors 43 and 44 that detect the rotational positions of the rotors of the motors MG1 and MG2. A rotational current and a phase current applied to the motors MG1 and MG2 detected by a current sensor (not shown) are input, and a switching control signal to the inverters 41 and 42 is output from the motor ECU 40. The motor ECU 40 is in communication with the hybrid electronic control unit 70, controls the driving of the motors MG1 and MG2 by a control signal from the hybrid electronic control unit 70, and, if necessary, data on the operating state of the motors MG1 and MG2. Output to the hybrid electronic control unit 70. The motor ECU 40 also calculates the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 based on signals from the rotational position detection sensors 43 and 44.

  The battery 50 is managed by a battery electronic control unit (hereinafter referred to as a battery ECU) 52. The battery ECU 52 receives signals necessary for managing the battery 50, for example, a voltage between terminals from a voltage sensor (not shown) installed between the terminals of the battery 50, and a power line 54 connected to the output terminal of the battery 50. The charging / discharging current from the attached current sensor (not shown), the battery temperature Tb from the temperature sensor 51 attached to the battery 50, and the like are input. Output to the control unit 70. The battery ECU 52 calculates the remaining capacity (SOC) based on the integrated value of the charge / discharge current detected by the current sensor to manage the battery 50, or based on the calculated remaining capacity SOC and the battery temperature Tb. The input / output limits Win and Wout, which are the maximum allowable power that may charge / discharge the battery 50, are calculated.

  The hybrid electronic control unit 70 is configured as a microprocessor centered on the CPU 72, and in addition to the CPU 72, a ROM 74 for storing processing programs, a RAM 76 for temporarily storing data, an input / output port and communication not shown. And a port. The hybrid electronic control unit 70 includes an ignition signal from an ignition switch 80, a shift position SP from a shift position sensor 82 that detects the operation position of the shift lever 81, and an accelerator pedal position sensor 84 that detects the amount of depression of the accelerator pedal 83. The accelerator opening Acc from the vehicle, the brake pedal position BP from the brake pedal position sensor 86 that detects the amount of depression of the brake pedal 85, the vehicle speed V from the vehicle speed sensor 88, and the driving mode as a normal mode that emphasizes fuel consumption or A mode setting signal or the like from a driving mode setting switch 89 for setting a power mode in which power can be output quickly can be input via an input port. As described above, the hybrid electronic control unit 70 is connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52 via the communication port, and exchanges various control signals and data with the engine ECU 24, the motor ECU 40, and the battery ECU 52. ing.

  The hybrid vehicle 20 according to the embodiment calculates the required torque Tr * to be output to the ring gear shaft 32a as the drive shaft based on the accelerator opening Acc corresponding to the depression amount of the accelerator pedal 83 by the driver and the vehicle speed V. 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 ring gear shaft 32a. As operation control of the engine 22, the motor MG1, and the motor MG2, 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 the power distribution and integration mechanism 30. Torque conversion operation mode for driving and controlling the motor MG1 and the motor MG2 so that the torque is converted by the motor MG1 and the motor MG2 and output to the ring gear shaft 32a, and the required power and the power required for charging and discharging the battery 50. The engine 22 is operated and controlled so that suitable power is output from the engine 22, and all or part of the power output from the engine 22 with charging / discharging of the battery 50 is the power distribution and integration mechanism 30, the motor MG1, and the motor. The required power is converted to the ring gear shaft 32 with torque conversion by MG2. Charge / discharge operation mode in which the motor MG1 and the motor MG2 are driven and controlled to be output to each other, and a motor operation mode in which the operation of the engine 22 is stopped and the power corresponding to the required power from the motor MG2 is output to the ring gear shaft 32a. and so on.

  Next, the operation of the hybrid vehicle 20 of the embodiment thus configured, particularly the operation when the accelerator is turned off while the power mode is selected and traveling is described. FIG. 2 is a flowchart illustrating an example of an accelerator-off time drive control routine executed by the hybrid electronic control unit 70 of the embodiment. This routine is repeatedly executed at predetermined time intervals (for example, every 8 msec) when the accelerator pedal 83 that has been depressed in a state where the power mode is set by the travel mode setting switch 89 is completely returned (accelerator off). The

  When the accelerator-off drive control routine is executed, the CPU 72 of the hybrid electronic control unit 70 firstly rotates the accelerator opening Acc from the accelerator pedal position sensor 84, the vehicle speed V from the vehicle speed sensor 88, and the motors MG1, MG2. A process of inputting data necessary for control, such as the numbers Nm1, Nm2, input / output limits Win and Wout of the battery 50, is executed (step S100). Here, the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 are input from the motor ECU 40 by communication from those calculated based on the rotational positions of the rotors of the motors MG1 and MG2 detected by the rotational position detection sensors 43 and 44. To do. The input / output limits Win and Wout of the battery 50 are set based on the battery temperature Tb of the battery 50 detected by the temperature sensor 51 and the remaining capacity (SOC) of the battery 50 from the battery ECU 52 by communication. To do.

  When the data is thus input, the required torque Tr * to be output to the ring gear shaft 32a as the drive shaft connected to the drive wheels 63a and 63b as the torque required for the vehicle when the accelerator is off based on the input vehicle speed V. Set (step S110). In the embodiment, the required torque Tr * is determined in advance by storing the relationship between the accelerator opening Acc, the vehicle speed V, and the required torque Tr * in the ROM 74 as a required torque setting map, and the accelerator opening Acc, the vehicle speed V, , The corresponding required torque Tr * is derived and set from the stored map. FIG. 3 shows an example of the required torque setting map. When the accelerator is off, the accelerator opening Acc is 0% (Acc = 0%).

  Next, the lower limit rotation speed Nemin of the engine 22 to be maintained in order to output power from the engine 22 quickly is set based on the vehicle speed V (step S120). In the embodiment, the lower limit rotational speed Nemin corresponds to the stored map in which the relationship between the vehicle speed V and the lower limit rotational speed Nemin is determined in advance and stored in the ROM 74 as a lower limit rotational speed setting map. The lower limit rotation speed Nemin was derived and set. FIG. 4 shows an example of a lower limit rotation speed setting map. Here, the larger the vehicle speed V, the larger the lower limit rotational speed Nemin. The larger the vehicle speed V, the greater the power required for acceleration, and a certain amount of time is required to increase the rotational speed Ne of the engine 22. And based on that.

  Subsequently, the vehicle speed V is compared with the threshold value Vfc and the threshold value Vs (step S130). Here, the threshold value Vfc is set as a vehicle speed at which fuel cut of the engine 22 is stopped and fuel is supplied to the engine 22, and for example, 30 km / h, 40 km / h, 50 km / h, or the like can be used. . The threshold value Vs is set as a vehicle speed that permits intermittent operation of the engine 22 in the power mode, and for example, 10 km / h, 20 km / h, 30 km / h, or the like can be used. In the embodiment, the threshold value Vfc is set to the vehicle speed after the lower limit rotational speed Nemin reaches the idle rotational speed Nidle, as shown in FIG.

  When it is determined that the vehicle speed V is equal to or higher than the threshold value Vfc, a fuel cut command for stopping the fuel supply of the engine 22 is transmitted to the engine ECU 24 (step S140). The engine ECU 24 that has received the fuel cut command stops the fuel injection control and the like in the engine 22. Subsequently, using the set lower limit rotational speed Nemin of the engine 22, the rotational speed Nr (Nm2 / Gr) of the ring gear shaft 32a, and the gear ratio ρ of the power distribution and integration mechanism 30, the target rotational speed of the motor MG1 is expressed by the following equation (1). The number Nm1 * is calculated, and the torque command Tm1 * of the motor MG1 is calculated by the equation (2) based on the calculated target speed Nm1 * and the current speed Nm1 (step S150). Here, Expression (1) is a dynamic relational expression for the rotating element of the power distribution and integration mechanism 30. FIG. 5 shows an example of a collinear diagram showing the dynamic relationship between the rotational speed and torque in the rotating elements of the power distribution and integration mechanism 30 when the vehicle speed V is equal to or higher than the threshold value Vfc. In the figure, the left S-axis indicates the rotation speed of the sun gear 31 that is the rotation speed Nm1 of the motor MG1, the C-axis indicates the rotation speed of the carrier 34 that is the rotation speed Ne of the engine 22, and the R-axis indicates the rotation speed of the motor MG2. The rotational speed Nr of the ring gear 32 obtained by multiplying the number Nm2 by the gear ratio Gr of the reduction gear 35 is shown. Expression (1) can be easily derived by using this alignment chart. The two thick arrows on the R axis indicate that the torque Tm1 output from the motor MG1 acts on the ring gear shaft 32a and the torque Tm2 output from the motor MG2 acts on the ring gear shaft 32a via the reduction gear 35. Torque. Expression (2) is a relational expression in feedback control for rotating the motor MG1 at the target rotational speed Nm1 *. In Expression (2), “k1” in the second term on the right side is a gain of a proportional term. “K2” in the third term on the right side is the gain of the integral term.

Nm1 * ＝ Nemin ・ (1 + ρ) / ρ−Nm2 / (Gr ・ ρ) (1)
Tm1 * = previous Tm1 * + k1 (Nm1 * −Nm1) + k2∫ (Nm1 * −Nm1) dt (2)

  Next, the deviation from the power consumption (generated power) of the motor MG1 obtained by multiplying the input / output limits Win and Wout of the battery 50 and the set torque command Tm1 * by the current rotational speed Nm1 of the motor MG1 is the rotation of the motor MG2. Torque limits Tm2min and Tm2max as upper and lower limits of torque that may be output from the motor MG2 by dividing by several Nm2 are calculated by the following equations (3) and (4) (step S210), and the required torque Tr * is calculated. A provisional motor which is a provisional value of torque to be output from the motor MG2 by adding a value obtained by dividing the set torque command Tm1 * by the gear ratio ρ of the power distribution and integration mechanism 30 and further dividing by the gear ratio Gr of the reduction gear 35 Torque Tm2tmp is calculated by the following equation (5) (step S220), and the set temporary motor torque Tm2tmp is calculated by the following equation (6). Torque limit Tm2min, and limited by Tm2max to set a torque command Tm2 * of the motor MG2 (step S230).

Tm2min ＝ (Win-Tm1 * ・ Nm1) / Nm2 (3)
Tm2max ＝ (Wout-Tm1 * ・ Nm1) / Nm2 (4)
Tm2tmp = (Tr * + Tm1 * / ρ) / Gr (5)
Tm2 * = max (min (Tm2tmp, Tm2max), Tm2min) (6)

  The torque command Tm1 * of the motor MG1 and the torque command Tm2 * of the motor MG2 set in this way are transmitted to the motor ECU 40 (step S240), and the accelerator-off-time drive control routine is terminated. Receiving the torque commands Tm1 * and Tm2 *, the motor ECU 40 controls the switching elements of the inverters 41 and 42 so that the motor MG1 is driven by the torque command Tm1 * and the motor MG2 is driven by the torque command Tm2 *. . With such control, the motor 22 can be driven at the lower limit rotational speed Nemin while the required torque Tr * is output to the ring gear shaft 32a as the drive shaft within the range of the input / output limits Win and Wout of the battery 50. . As a result, when the accelerator pedal 83 is depressed, the necessary power can be quickly output from the engine 22 and the torque corresponding to the depression of the accelerator pedal 83 can be output for acceleration.

  When it is determined in step S130 that the vehicle speed V is less than the threshold value Vfc and greater than or equal to the threshold value Vs, a self-sustained operation command is transmitted to the engine ECU 24 so that the engine 22 operates independently at the lower limit rotation speed Nemin (step S160). The torque command Tm1 * is set to a value of 0 (step S170), the above-described steps S210 to S240 are executed, and the accelerator-off time drive control routine is terminated. The engine ECU 24 that has received the self-sustained operation command performs control such as intake air amount control, fuel injection control, and ignition control so that the engine 22 operates independently at the lower limit rotational speed Nemin (in the example, the idle rotational speed Nidle). . By such control, the engine 22 is driven to output the required torque Tr * to the ring gear shaft 32a within the range of the input and output limits Win and Wout of the battery 50 while operating the engine 22 independently at the lower limit rotational speed Nemin (idle rotational speed Nidle). Can do. As described above, when the vehicle speed V is less than the threshold value Vfc and is equal to or higher than the threshold value Vs, the engine 22 is operated autonomously, so that the remaining capacity (SOC) of the battery 50 is prevented from being significantly reduced as compared with the case where the engine 22 is motored. can do. FIG. 6 shows an example of a collinear diagram showing the dynamic relationship between the rotational speed and torque in the rotating elements of the power distribution and integration mechanism 30 when the vehicle speed V is less than the threshold value Vfc and greater than or equal to the threshold value Vs.

  When it is determined in step S130 that the vehicle speed V is less than the threshold value Vs, it is determined whether or not the driving continuation condition for intermittent operation of the other engine 22 is satisfied (step S180), and the driving continuation condition is satisfied. When the vehicle speed V is lower than the threshold value Vfc and equal to or higher than the threshold value Vs, the required torque Tr * is within the range of the input / output limits Win and Wout of the battery 50 while the engine 22 is independently operated at the lower limit rotation speed Nemin. Is output to the ring gear shaft 32a (steps S160, S170, S210 to S240), and when the operation continuation condition is not satisfied, an engine stop command for stopping the operation of the engine 22 is transmitted to the engine ECU ( Step S190), a value 0 is set to the torque command Tm1 * of the motor MG1 (Step S200), It performs the process of the step S210~S240 ends the accelerator-off drive control routine. By such control, the engine 22 can be intermittently operated even when the power mode is selected.

  According to the hybrid vehicle 20 of the embodiment described above, the fuel supply to the engine 22 is stopped until the vehicle speed V becomes less than the threshold value Vfc when the accelerator is turned off while the power mode is selected and the vehicle is traveling. (Fuel cut) and motoring is performed by the motor MG1 so that the engine 22 rotates at the lower limit rotation speed Nemin based on the vehicle speed V. After the vehicle speed V reaches less than the threshold value Vfc, fuel supply to the engine 22 is resumed and the vehicle speed is resumed. Since the engine 22 is independently operated at the lower limit rotation speed Nemin based on V, power can be output from the engine 22 quickly when acceleration is requested, and the fuel efficiency of the vehicle can be improved, and the remaining capacity (SOC) of the battery 50 Can be significantly reduced. In addition, since the intermittent operation of the engine 22 is permitted when the vehicle speed V reaches less than the threshold value Vs, the engine 22 can be intermittently operated even when the power mode is set, and fuel consumption can be improved.

  In the hybrid vehicle 20 of the embodiment, the fuel supply to the engine 22 is stopped until the vehicle speed V is less than the threshold value Vfc, and the motor 22 is motored so that the engine 22 rotates at the lower limit rotation speed Nemin based on the vehicle speed V. After the vehicle speed V reaches less than the threshold value Vfc, the fuel supply to the engine 22 is resumed and the engine 22 is operated autonomously at the lower limit rotation speed Nemin based on the vehicle speed V. It is good also as what gives a hysteresis to switching. In this case, the threshold value Vs for permitting intermittent operation of the engine 22 may be provided with hysteresis. FIG. 7 shows an example of the relationship between the vehicle speed V and the threshold value when switching between motoring and independent operation of the engine 22 with hysteresis and permitting or prohibiting intermittent operation of the engine 22 with hysteresis.

  In the hybrid vehicle 20 of the embodiment, the intermittent operation of the engine 22 is permitted when the vehicle speed V reaches less than the threshold value Vs. However, the intermittent operation of the engine 22 may not be permitted in the power mode.

  In the hybrid vehicle 20 of the embodiment, the larger lower limit rotation speed Nemin is set as the vehicle speed V is larger. However, a constant lower limit rotation speed Nemin may be set regardless of the vehicle speed V.

  In the hybrid vehicle 20 of the embodiment, two driving modes, the normal mode and the power mode, are set as the driving mode, but other accompanying modes other than the normal mode and the power mode can be set. It doesn't matter.

  In the hybrid vehicle 20 of the embodiment, the power of the motor MG2 is decelerated by the reduction gear 35 and output to the ring gear shaft 32a. However, as illustrated in the hybrid vehicle 120 of the modified example of FIG. May be connected to an axle (an axle connected to the wheels 64a and 64b in FIG. 8) different from an axle to which the ring gear shaft 32a is connected (an axle to which the drive wheels 63a and 63b are connected).

  In the hybrid vehicle 20 of the embodiment, the power of the engine 22 is output to the ring gear shaft 32a as the drive shaft connected to the drive wheels 63a and 63b via the power distribution and integration mechanism 30, but the modified example of FIG. The hybrid vehicle 220 includes an inner rotor 232 connected to the crankshaft 26 of the engine 22 and an outer rotor 234 connected to a drive shaft that outputs power to the drive wheels 63a and 63b. A counter-rotor motor 230 that transmits a part of the power to the drive shaft and converts the remaining power into electric power may be provided.

  Here, the correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the engine 22 corresponds to an “internal combustion engine”, the power distribution and integration mechanism 30 and the motor MG1 correspond to “power power input / output means”, the motor MG2 corresponds to “electric motor”, and the battery 50 corresponds to “ The vehicle speed sensor 88 corresponds to “vehicle speed detection means”, the travel mode setting switch 89 corresponds to “mode changeover switch”, and the lower limit rotation speed Nemin is set based on the vehicle speed V. The hybrid ECU 70 that executes the process of step S120 of the accelerator-off drive control routine corresponds to the “lower limit rotational speed setting means”, and sets the required torque required for the drive shaft 32a based on the accelerator opening Acc and the vehicle speed V. The hybrid ECU 70 that executes the process of step S110 of the accelerator-off-time drive control routine of FIG. 2 corresponds to “required drive force setting means”. When the accelerator mode is turned off while the power mode is set by the travel mode setting switch 89 and the vehicle is traveling, an engine stop command is transmitted to the engine ECU 24 until the vehicle speed V becomes less than the threshold value Vfc, and the fuel of the engine 22 is cut. The motor MG1, so that the engine 22 is motored by the motor MG1 at the lower limit rotational speed Nemin based on the vehicle speed V and the required torque Tr * is output to the ring gear shaft 32a within the range of the input / output limits Win, Wout of the battery 50. MG2 torque commands Tm1 * and Tm2 * are set and transmitted to the motor ECU 40. After the vehicle speed V reaches less than the threshold value Vfc, an engine self-sustained operation command is transmitted to the engine ECU 24 and the engine 22 is self-sustaining at the lower limit rotational speed Nemin. Input / output limit Win, W of battery 50 while driving Step S130 of the accelerator-off time drive control routine of FIG. 2 that sets torque commands Tm1 * and Tm2 * of the motors MG1 and MG2 so as to output the required torque Tr * to the ring gear shaft 32a within the range of ut and transmits them to the motor ECU 40. To ECU 240 for executing the processes of S240, an engine ECU 24 for controlling the engine 22 based on an engine stop command and an engine self-sustained operation command, and a motor ECU 40 for driving and controlling the motors MG1, MG2 based on torque commands Tm1 *, Tm2 * Corresponds to “control means”. Further, the motor MG1 corresponds to a “generator”, and the power distribution and integration mechanism 30 corresponds to a “3-axis power input / output unit”. Further, the anti-rotor motor 230 also corresponds to “power power input / output means”.

  Here, the “internal combustion engine” is not limited to an internal combustion engine that outputs power using a hydrocarbon fuel such as gasoline or light oil, and may be any type of internal combustion engine such as a hydrogen engine. The “power power input / output means” is not limited to the combination of the power distribution and integration mechanism 30 and the motor MG1 or the counter-rotor motor 230, and is connected to the drive shaft connected to the wheels. As long as it is connected to the output shaft of the internal combustion engine so as to be able to rotate independently of the drive shaft, and can input and output power to and from the drive shaft and output shaft together with input and output of electric power and power, it may be anything. . The “motor” is not limited to the motor MG2 configured as a synchronous generator motor, and may be any type of motor as long as it can input and output driving power, such as an induction motor. The “power storage means” is not limited to the battery 50 as a secondary battery, and may be anything as long as power can be exchanged with the power power input / output means and the motor, such as a capacitor. The “vehicle speed detection means” is not limited to the vehicle speed sensor 88, but may be any device that detects the vehicle speed, such as a calculation based on a signal from a wheel speed sensor attached to a driving wheel or a driven wheel. It doesn't matter what. The “mode changeover switch” is not limited to the travel mode setting switch 89, and the fuel consumption is reduced compared to the normal travel mode and the normal travel mode in which the fuel efficiency is relatively prioritized, but the power is quickly increased. As long as it is possible to switch between the power priority mode in which the vehicle can output and travel, any method can be used. The “lower limit rotational speed setting means” may be of any type as long as it sets the rotational speed of the internal combustion engine based on the vehicle speed. The “required driving force setting means” is not limited to one that sets the required torque Tr * required for the ring gear shaft 32a based on the accelerator opening Acc and the vehicle speed V, but only the accelerator opening Acc. Those that set the required driving force required for travel, such as those that set the required torque based on them, and those that set the required torque based on the travel position on the travel route if the travel route is preset Anything can be used. The “control means” is not limited to the combination of the hybrid electronic control unit 70, the engine ECU 24, and the motor ECU 40, and may be configured by a single electronic control unit. Further, as the “control means”, when the accelerator is turned off while the power mode is set by the travel mode setting switch 89 and the vehicle is traveling, the fuel of the engine 22 is cut until the vehicle speed V becomes less than the threshold value Vfc. The motors MG1, MG2, and MG2 are controlled so that the engine 22 is motored by the motor MG1 at the lower limit speed Nemin based on the vehicle speed V and the required torque Tr * is output to the ring gear shaft 32a within the range of the input / output limits Win and Wout of the battery 50. After the engine 22 is controlled and the vehicle speed V reaches less than the threshold value Vfc, the engine 22 operates independently at the lower limit rotation speed Nemin, and the required torque Tr * is set within the range of the input / output limits Win and Wout of the battery 50 and the ring gear shaft 32a. For controlling motors MG1, MG2 and engine 22 to output to Without limitation, when the accelerator is turned off while the power priority mode is set and the vehicle is traveling, when the vehicle speed is equal to or higher than the predetermined vehicle speed, the fuel supply to the internal combustion engine is stopped and the internal combustion engine is at the lower limit. The internal combustion engine, the power drive input / output means and the motor are controlled so as to rotate at the rotational speed and travel with the required driving force. When the vehicle speed is lower than the predetermined vehicle speed, the internal combustion engine operates independently at the rotational speed and travels with the required driving force. As long as it controls the internal combustion engine, the power input / output means, and the electric motor, it may be anything.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. It is an example for specifically explaining the best mode for doing so, and does not limit the elements of the invention described in the column of means for solving the problem. That is, the interpretation of the invention described in the column of means for solving the problems should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problems. It is only a specific example.

  The best mode for carrying out the present invention has been described with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the gist of the present invention. Of course, it can be implemented in the form.

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

1 is a configuration diagram showing an outline of the configuration of a hybrid vehicle 20. FIG. It is a flowchart which shows an example of the drive control routine at the time of the accelerator off performed by the electronic control unit for hybrids 70 of an Example. It is explanatory drawing which shows an example of the map for request | requirement torque setting. It is explanatory drawing which shows an example of the map for a minimum rotation speed setting. It is explanatory drawing which shows an example of the collinear diagram which shows the dynamic relationship of the rotation speed and torque in the rotation element of the power distribution integration mechanism 30 when the vehicle speed V is more than threshold value Vfc. It is explanatory drawing which shows an example of the collinear diagram which shows the dynamic relationship of the rotation speed and torque in the rotation element of the power distribution integration mechanism 30 when the vehicle speed V is smaller than threshold value Vfc and more than threshold value Vs. It is explanatory drawing which shows a mode that the driving state of the engine 22 is switched with respect to the vehicle speed V. FIG. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 120 according to a modification. FIG. 11 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 220 of a modified example.

Explanation of symbols

  20, 120, 220 Hybrid vehicle, 22 engine, 24 engine electronic control unit (engine ECU), 26 crankshaft, 28 damper, 30 power distribution integration mechanism, 31 sun gear, 32 ring gear, 32a ring gear shaft, 34 carrier, 35 deceleration Gear, 40 Motor electronic control unit (motor ECU), 41, 42 Inverter, 43, 44 Rotation position detection sensor, 50 battery, 51 Temperature sensor, 52 Battery electronic control unit (battery ECU), 54 Power line, 60 Gear Mechanism, 62 differential gear, 63a, 63b drive wheel, 64a, 64b wheel, 70 hybrid electronic control unit, 72 CPU, 74 ROM, 76 RAM, 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 sensor, 88 Vehicle speed sensor, 89 Travel mode setting switch, 230 Pair rotor motor, 232 Inner rotor, 234 Outer rotor, MG1 , MG2 motor.

Claims (6)

An internal combustion engine;
Connected to the drive shaft connected to the wheels and connected to the output shaft of the internal combustion engine so as to be rotatable independently of the drive shaft, and to the drive shaft and the output shaft with input and output of electric power and power Electric power input / output means for inputting / outputting power;
An electric motor that inputs and outputs driving power;
A power storage means for exchanging power with the electric power drive input / output means and the electric motor;
Vehicle speed detection means for detecting the vehicle speed;
A mode changeover switch that switches between a normal driving mode for driving with relatively high priority on fuel consumption and a power priority mode for reducing the fuel consumption as compared with the normal driving mode but capable of driving by quickly outputting power. When,
Lower limit speed setting means for setting a lower limit speed of the internal combustion engine based on the detected vehicle speed when the power priority mode is set by the mode changeover switch;
Required driving force setting means for setting required driving force required for traveling;
When the accelerator is turned off while traveling with the power priority mode set by the mode switch, the fuel supply to the internal combustion engine is stopped when the detected vehicle speed exceeds a predetermined vehicle speed. The internal combustion engine, the electric power drive input / output means, and the electric motor are controlled so that the internal combustion engine rotates at the set lower limit rotation speed and travels with the set required driving force, and the detected vehicle speed is Control for controlling the internal combustion engine, the power power input / output means, and the electric motor so that the internal combustion engine operates independently at the set lower limit rotational speed and travels with the set required driving force when the vehicle speed is lower than a predetermined vehicle speed. Means,
A hybrid car with   When the detected vehicle speed is less than the stop vehicle speed less than the predetermined vehicle speed, the control means is configured to input the electric power and the internal combustion engine so as to run with the set required driving force while the operation of the internal combustion engine is stopped. 2. The hybrid vehicle according to claim 1, wherein said hybrid vehicle is means for controlling output means and said electric motor.   The hybrid vehicle according to claim 1 or 2, wherein the lower limit rotational speed setting means is a means for setting the lower limit rotational speed such that the lower limit rotational speed tends to increase as the detected vehicle speed increases.   The hybrid vehicle according to any one of claims 1 to 3, wherein the control means is a means for controlling the vehicle using a vehicle speed having hysteresis as the predetermined vehicle speed.   The power power input / output means is connected to three axes of a generator capable of inputting / outputting power, an output shaft of the internal combustion engine, the drive shaft, and a rotating shaft of the generator, and one of the three shafts 5. The hybrid according to claim 1, further comprising: a three-axis power input / output unit that inputs / outputs power to the remaining shaft based on power input / output to / from the two shafts. car. Connected to the internal combustion engine and a drive shaft connected to the wheels and connected to the output shaft of the internal combustion engine so as to be rotatable independently of the drive shaft, the drive shaft and the output with input and output of electric power and power Electric power input / output means for inputting / outputting power to / from the shaft, an electric motor for inputting / outputting driving power, an electric power input / output means, and an electric storage means for exchanging electric power with the electric motor, and comparatively prioritizing fuel consumption And a mode changeover switch for switching and setting a normal driving mode for driving and a power priority mode capable of driving by quickly outputting power while reducing fuel consumption compared to the normal driving mode A vehicle control method,
When the accelerator is turned off while the power priority mode is set by the mode switch, and the vehicle speed is equal to or higher than a predetermined vehicle speed, the internal combustion engine is stopped while the fuel supply to the internal combustion engine is stopped. The internal combustion engine, the power power input / output means, and the electric motor are controlled to rotate at the lower limit rotational speed set based on the vehicle and to drive with the required driving force required for traveling, and the vehicle speed is less than the predetermined vehicle speed. Sometimes the internal combustion engine, the electric power drive input / output means and the electric motor are controlled so that the internal combustion engine runs independently at the lower limit rotational speed and travels with the required driving force.
Control method of hybrid vehicle.

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