JP6693363B2 - Hybrid car - Google Patents

Description

  The present invention relates to a hybrid vehicle, and more specifically, a first motor, an engine, and a drive shaft connected to an axle are connected to a first rotary element, a second rotary element, and a third rotary element, which are arranged in order in a collinear diagram of a planetary gear. Regarding hybrid cars.

  Conventionally, as a hybrid vehicle of this type, a first motor, an engine, and a drive shaft connected to an axle are connected to a first rotary element, a second rotary element, and a third rotary element arranged in order in a collinear diagram of a planetary gear. A hybrid vehicle has been proposed (for example, see Patent Document 1). In this hybrid vehicle, control is performed to increase the engine speed when the vehicle cannot get over the step only by the output of the maximum allowable torque from the second motor during reverse running. When the engine speed is increased, the sum of the friction torque due to the engine friction and the inertia torque based on the rate of increase of the engine speed acts on the drive shaft in the reverse direction. Therefore, the maximum allowable torque is output from the second motor and the engine speed is increased to output a larger torque in the reverse direction to overcome the step.

JP, 2005-116922, A

  However, in the above-described hybrid vehicle, the maximum rotation speed of the engine is limited by the maximum rotation speed of the motor MG1 and the maximum rotation speed of the pinion gear of the planetary gear 30. In order for a vehicle to get over a step, it is considered that sufficient energy and torque must be applied to get over the step, but if the maximum engine speed is limited, the engine speed will be increased at the maximum allowable rate of increase. The energy and torque when raised raises a step that cannot be overcome.

  The main purpose of the hybrid vehicle of the present invention is to overcome a higher step in the reverse direction.

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

The hybrid vehicle of the present invention is
Engine,
A first motor,
A planetary gear in which a drive shaft connected to the first motor, the engine, and an axle is connected to a first rotating element, a second rotating element, and a third rotating element that are arranged in order in the alignment chart;
A second motor capable of outputting power to the drive shaft;
A control device that controls the engine, the first motor, and the second motor, and that determines a reverse step over when the vehicle cannot go over the step only by outputting an allowable maximum torque from the second motor during reverse traveling,
In a hybrid vehicle equipped with
When the control device determines that the reverse step is crossed, the second motor outputs the maximum allowable torque and the engine is rotated in the reverse rotation direction, and then the engine is rotated in the forward rotation direction. To control the first motor and the second motor so that
It is characterized by

  In this hybrid vehicle of the present invention, when it is determined that the vehicle is over the reverse step, the maximum allowable torque is output from the second motor, and the engine is rotated in the reverse rotation direction after the engine is rotated in the reverse rotation direction. The first motor and the second motor are controlled so as to be in the operating state. As a result, the energy can be increased as compared with the case where the engine is controlled so that the engine is rotated in the forward rotation direction from the stopped state, and the higher step in the reverse direction is overcome. You will be able to do that. When the engine is rotating in the forward rotation direction from the state in which the engine is rotating in the reverse rotation direction, the increase rate of the engine rotation speed is the maximum increase allowed as the increase rate of the engine rotation speed. It is preferable to set it as a rate. Also, when the engine is rotating in the reverse rotation direction, the friction torque due to the reverse rotation of the engine rotates in the reverse rotation direction at a rotation speed commensurate with the inertia torque when the rotation speed of the engine is changed at the maximum increase rate. It is preferable to set it in a state where

It is a block diagram which shows the outline of a structure of the hybrid vehicle 20 as an Example of this invention. 5 is a flowchart showing an example of a reverse traveling control routine executed by the HVECU 70. It is explanatory drawing demonstrated using the collinear chart which shows the dynamic relationship of the rotation speed and torque in the rotary element of the planetary gear 30. FIG. 6 is an explanatory diagram illustrating a relationship between a torque Te of the engine 22 and a rotation speed Ne of the engine 22. FIG. 8 is an explanatory diagram showing an example of temporal changes in vehicle speed V, motor torques Tm1, Tm2, and engine speed Ne of the engine 22 when overcoming a step during reverse traveling.

  Next, modes 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 illustrated, the hybrid vehicle 20 of the embodiment includes an engine 22, a planetary gear 30, motors MG1 and MG2, inverters 41 and 42, a battery 50, and a hybrid electronic control unit (hereinafter referred to as "HVECU"). And 70.

  The engine 22 is configured as an internal combustion engine that outputs power using gasoline, light oil, or the like as fuel. The operation of the engine 22 is 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, in addition to the CPU, a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port. .. The engine ECU 24 sends signals from various sensors necessary for controlling the operation of the engine 22, for example, a crank angle θcr from a crank position sensor 23a that detects a rotational position of a crankshaft 26 of the engine 22 and a flow of cooling water. Cooling water temperature Tw from a temperature sensor (not shown) attached to the passage is input from the input port. Various control signals for controlling the operation of the engine 22 are output from the engine ECU 24 through the output port. The engine ECU 24 is connected to the HVECU 70 via a communication port. The engine ECU 24 calculates the rotation speed Ne of the engine 22 based on the crank angle θcr from the crank position sensor 23a.

  The planetary gear 30 is configured as a single pinion type planetary gear mechanism. The sun gear of the planetary gear 30 is connected to the rotor of the motor MG1. The ring gear of the planetary gear 30 is connected to a drive shaft 36 that is connected to the drive wheels 39a and 39b via a differential gear 38. The crankshaft 26 of the engine 22 is connected to the carrier of the planetary gear 30 via a damper 28.

  The motor MG1 is configured as, for example, 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, for example, a synchronous generator motor, and the rotor is connected to the drive shaft 36. Inverters 41 and 42 are connected to motors MG1 and MG2, and are also connected to battery 50 via power line 54. The motors MG1 and MG2 are rotationally driven by switching control of a plurality of switching elements (not shown) of the inverters 41 and 42 by an electronic control unit for motor (hereinafter referred to as “motor ECU”) 40.

  Although not shown, the motor ECU 40 is configured as a microprocessor centered on a CPU, and includes, in addition to the CPU, a ROM that stores a processing program, a RAM that temporarily stores data, an input / output port, and a communication port. .. The motor ECU 40 has signals from various sensors necessary for driving and controlling the motors MG1 and MG2, for example, rotational positions θm1 from rotational position detection sensors 43 and 44 that detect rotational positions of rotors of the motors MG1 and MG2. , Θm2, etc. are input through the input port. From the motor ECU 40, switching control signals to a plurality of switching elements (not shown) of the inverters 41 and 42 are output via the output port. The motor ECU 40 is connected to the HVECU 70 via a communication port. Motor ECU 40 calculates rotation speeds Nm1 and Nm2 of motors MG1 and MG2 based on rotation positions θm1 and θm2 of rotors of motors MG1 and MG2 from rotation position detection sensors 43 and 44.

  The battery 50 is configured as, for example, a lithium ion secondary battery or a nickel hydrogen secondary battery, and is connected to the inverters 41 and 42 via a power line 54. The battery 50 is managed by a battery electronic control unit (hereinafter referred to as “battery ECU”) 52.

  Although not shown, the battery ECU 52 is configured as a microprocessor centered on a CPU, and includes, in addition to the CPU, a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port. .. Signals from various sensors necessary for managing the battery 50 are input to the battery ECU 52 via an input port. The signals input to the battery ECU 52 include, for example, the battery voltage Vb from the voltage sensor 51 a installed between the terminals of the battery 50, the battery current Ib from the current sensor 51 b installed at the output terminal of the battery 50, and the battery 50. The battery temperature Tb from the temperature sensor 51c attached to the can be mentioned. The battery ECU 52 is connected to the HVECU 70 via a communication port. The battery ECU 52 calculates the charge ratio SOC based on the integrated value of the battery current Ib from the current sensor 51b. The charge ratio SOC is the ratio of the capacity of the electric power that can be discharged from the battery 50 to the total capacity of the battery 50.

  Although not shown, the HVECU 70 is configured as a microprocessor centered on a CPU, and in addition to the CPU, a ROM that stores a processing program, a RAM that temporarily stores data, a flash memory, an input / output port, and a communication port. Equipped with. Signals from various sensors are input to the HVECU 70 via input ports. Examples of the signal input to the HVECU 70 include an ignition signal IG from the ignition switch 80 and a shift position SP from a shift position sensor 82 that detects the operation position of the shift lever 81. Further, an accelerator pedal position Acc from an accelerator pedal position sensor 84 that detects the depression amount of the accelerator pedal 83, a brake pedal position BP from a brake pedal position sensor 86 that detects the depression amount of the brake pedal 85, and a vehicle speed sensor 88 from the vehicle speed sensor 88. The vehicle speed V can also be mentioned. As described above, the HVECU 70 is connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52 via the communication port. In the hybrid vehicle 20 of the embodiment, the operating position of the shift lever 81 (shift position SP detected by the shift position sensor 82) is the parking position used during parking (P position) and the reverse position for reverse traveling (R position). Position), neutral neutral position (N position), forward drive position (D position), and the like.

  In the hybrid vehicle 20 of the embodiment configured in this way, the hybrid vehicle mode (HV traveling mode) in which the engine 22 is traveling and the operation of the engine 22 (fuel injection control, etc.) are stopped when traveling forward. The vehicle travels in an electric travel mode (EV travel mode), and basically travels in the EV travel mode when traveling in reverse.

  In the HV traveling mode, drive control is performed as follows. A required torque Tr * required for traveling (a positive value when traveling forward) is set based on the accelerator opening Acc and the vehicle speed V. The traveling power Pdrv * required for traveling is calculated by multiplying the set required torque Tr * by the rotational speed Nr of the drive shaft 36 (for example, the rotational speed Nm2 of the motor MG2 (a positive value when traveling forward)). The required power Pe * required for the vehicle is obtained by subtracting the charge / discharge required power Pb * of the battery 50 based on the storage ratio SOC of the battery 50 (a positive value when the battery 50 is discharged) from the calculated traveling power Pdrv *. Set. The target rotation speed Ne * and the target torque Te * of the engine 22 are set using the required power Pe * and an operation line for efficiently operating the engine 22 (for example, an optimal fuel consumption operation line). The torque command Tm1 * of the motor MG1 is set by the rotation speed feedback control so that the rotation speed Ne of the engine 22 becomes the target rotation speed Ne *. When the motor MG1 is driven by the torque command Tm1 *, the torque output from the motor MG1 and transmitted to the drive shaft 36 via the planetary gear 30 is subtracted from the required torque Tr * to calculate the temporary torque Tm2tmp of the motor MG2. Motor MG2 is obtained by subtracting power consumption (generated power) of motor MG1 obtained by multiplying torque command Tm1 * of MG1 by rotation speed Nm1 from input / output limits Win, Wout of battery 50 and further dividing by rotation speed Nm2 of motor MG2. Torque limits Tm2min and Tm2max are calculated, and the temporary torque Tm2tmp is limited by the torque limits Tm2min and Tm2max and the positive and negative rated torques Tm2rat1 and Tm2rat2 to calculate the torque command Tm2 * of the motor MG2. Here, the rated torques Tm2rat1 and Tm2rat2 are set by applying the rotational speed Nm2 to a map in which the relationship between the rotational speed Nm2 of the motor MG2 and the rated torques Tm2rat1 and Tm2rat2 is predetermined. Then, the target rotation speed Ne * and the target torque Te * are transmitted to the engine ECU 24, and the torque commands Tm1 * and Tm2 * are transmitted to the motor ECU 40. The engine ECU 24, which has received the target rotation speed Ne * and the target torque Te *, controls the intake air amount of the engine 22, the fuel injection control, and the ignition so that the engine 22 is driven by the target rotation speed Ne * and the target torque Te *. Controls etc. Further, the motor ECU 40 that has received the torque commands Tm1 * and Tm2 * performs switching control of the plurality of switching elements of the inverters 41 and 42 so that the motors MG1 and MG2 are driven by the torque commands Tm1 * and Tm2 *.

  In the EV traveling mode, drive control is performed as follows. The required torque Tr * is set based on the accelerator opening Acc and the vehicle speed V, the torque command Tm1 * of the motor MG1 is set to the value 0, and the torque command Tm2 * of the motor MG2 is set in the same manner as when the vehicle is running in the HV running mode. Is set and transmitted to the motor ECU 40. Then, the motor ECU 40 having received the torque commands Tm1 *, Tm2 * performs switching control of the switching elements of the inverters 41, 42 so that the motors MG1, MG2 are driven by the torque commands Tm1 *, Tm2 *.

  Further, in the hybrid vehicle 20 of the embodiment, when it is determined that the current is concentrated and flows in the specific phase of the motor MG2 (the second motor is in the motor lock state), the current is supplied to the specific phase of the motor MG2. Until it is determined that the concentrated flow of the torque has been released, the lock protection control for reducing and holding the absolute value of the torque command Tm2 * of the motor MG2 to a predetermined value T1 slightly larger than the value 0 is executed. This lock protection control suppresses overheating of the motor MG2 in consideration that the temperature rise of the motor MG2 is likely to be promoted by the heat generation in the specific phase when the current concentrates in the specific phase of the motor MG2. To be done for. The start condition of the lock protection control is, for example, one of the currents Iu, Iv, and Iw flowing in each phase of the motor MG2 being a predetermined value or more for a predetermined time (for example, several hundred msec or 1 second). Conditions or the like can be used. Further, the unlocking condition of the lock protection control is, for example, a condition in which the motor MG2 rotates during execution of the lock protection control and the current which is equal to or more than a predetermined value among the currents Iu, Iv, and Iw has become less than the predetermined value. Can be used. For example, considering the case of trying to get over a step in reverse traveling, when the motor MG2 enters a motor lock state due to a slight depression of the tire of the rear wheel when approaching the step, the lock protection control is started, and then, The lock protection control is released when the vehicle slightly moves forward due to the elastic force (repulsive force) of the tires of the rear wheels as the absolute value of the torque of the motor MG2 decreases.

  Next, an operation of the hybrid vehicle 20 of the embodiment thus configured, particularly an operation when the shift position SP is set to the reverse position (R position) and a step is attempted to be overcome in reverse traveling will be described. FIG. 2 is a flowchart showing an example of a reverse traveling control routine executed by the HVECU 70. This routine is repeatedly executed every predetermined time (for example, every several msec) when the shift position SP is set to the reverse position (R position). Note that, in parallel with this routine, the control during reverse traveling by the motor MG2 is performed by the above-described drive control.

  When the reverse running control routine is executed, the HVECU 70 first determines the accelerator opening Acc from the accelerator pedal position sensor 84, the vehicle speed V from the vehicle speed sensor 88, the torque Tm2 of the motor MG2, the rotation speed Ne of the engine 22, and the like. Data is input (step S100). Here, as the torque Tm2 of the motor MG2, the torque estimated based on the phase current of each phase of the motor MG2 is input from the motor ECU 40 by communication. The torque command Tm2 * of the motor MG2 may be used. Further, the rotation speed Ne of the engine 22 is calculated based on a signal from the crank position sensor 23a attached to the crankshaft 26, and is input by communication from the engine ECU 24.

  When the data is thus input, the input accelerator opening degree Acc is compared with the threshold value Aref (step S110), and the vehicle speed V is compared with the threshold value Vref (step S120). Here, the threshold value Aref and the threshold value Vref indicate whether or not the vehicle speed V is low but the driver is depressing the accelerator pedal 83 greatly, specifically, whether or not the vehicle is trying to get over a step in reverse running. The threshold Aref may be 80% or 90%, and the threshold Vref may be 1 km / h or 2 km / h.

  When the accelerator opening Acc is less than the threshold value Aref or when the vehicle speed V is higher than the threshold value Vref, it is judged that the situation is not trying to get over the step in reverse running, and the routine is finished as it is. In this case, by the drive control described above, the torque corresponding to the accelerator opening Acc is output from the motor MG2.

   When the accelerator opening Acc is greater than or equal to the threshold value Aref and the vehicle speed V is less than or equal to the threshold value Vref, it is determined that the vehicle is trying to get over the step in reverse traveling, and it is determined whether the lock protection control of the motor MG2 is being performed. (Step S130). When the lock protection control is being executed, it is determined whether or not the engine 22 is stopped (step S150). When the engine 22 is not stopped, the engine 22 is stopped (step S160) and this routine is executed. When the engine 22 is stopped and the engine 22 is stopped, this routine is ended as it is. When the accelerator opening Acc is greater than or equal to the threshold value Aref, the motor MG2 is basically controlled by setting the negative rated torque Tm2rat2 to the torque command Tm2 *, except when the lock protection control is executed. To be done.

  When it is determined in step S130 that the lock protection control is not executed, it is determined whether the torque Tm2 of the motor MG2 is equal to the negative rated torque Tm2rat2 (step S140). When the torque Tm2 of the motor MG2 is not equal to the rated torque Tm2rat2 on the negative side, the process of stopping the engine 22 when the engine 22 is not stopped (steps S150 and S160 are executed, and this routine is ended).

  When it is determined in step S140 that the torque Tm2 of the motor MG2 is equal to the negative rated torque Tm2rat2, it is determined whether the engine 22 is stopped (step S170). When the engine 22 is stopped, the value obtained by counting up the counter C by the up amount Cstep is set as a new counter C (step S180), and it is determined whether the counter C is equal to or more than the threshold value Cref (step S190). This counter C becomes the threshold value Cref or more when the vehicle speed V is equal to or less than the threshold value Vref and is kept substantially stopped for a certain period of time despite the negative rated torque Tm2rat2 being output from the motor MG2 while the engine 22 is stopped. From this, it can be said that this is a counter for determining that the vehicle is over a step during reverse traveling. It should be noted that the up amount Cstep is determined by the time for holding for a fixed time and the frequency of repeatedly executing this routine. When the counter C is less than the threshold value Cref, this routine ends.

  When this routine is repeatedly executed and it is determined in step S190 that the counter C is greater than or equal to the threshold value Cref, the stopped engine 22 starts reverse rotation (step S200). In the reverse rotation of the engine 22, the torque command Tm1 * of the motor MG1 is set to a predetermined torque in the direction of reverse rotation of the stopped engine 22 and transmitted to the motor ECU 40, and the motor ECU 40 changes the torque command Tm1 * from the motor MG1. This can be performed by controlling the switching of the switching element of the inverter 41 so that the corresponding torque is output.

  When the reverse rotation of the engine 22 is started, the rotation speed Ne of the engine 22 increases to the negative side. Therefore, in step S170, it is determined that the engine 22 is not stopped. In this case, it is determined whether the rotation speed Ne of the engine 22 matches the reverse rotation lower limit threshold Nelimm (step S210). Here, in the embodiment, the lower limit threshold value Nelimm for reverse rotation is a rotation speed in which the friction torque Tef of the engine 22 which is rotating in reverse corresponds to the inertia torque Tei when the rotation speed Ne of the engine 22 is increased at the maximum increase rate. Although it is a number, the number of revolutions may be smaller than this number of revolutions (large number of revolutions in absolute value) or may be larger than this number of revolutions (small number of revolutions in absolute value). Until the rotation speed Ne of the engine 22 matches the lower limit threshold value Nelimm for reverse rotation, a negative determination is made in step S210, and it is determined whether the rotation speed Ne of the engine 22 matches the upper limit threshold value Nelimp for forward rotation. (Step S230). Although the upper limit threshold value Nelimp for normal rotation is the upper limit rotation speed of the engine 22 determined by the upper limit rotation speed of the motor MG1 in the embodiment, it may be a rotation speed slightly smaller than this rotation speed. Since the reverse rotation of the engine 22 is now considered, a negative determination is made in step S230, and this routine ends. That is, when the reverse rotation of the engine 22 is started, the reverse rotation of the engine 22 is started, that is, the torque command Tm1 * of the motor MG1 is kept until the rotation speed Ne of the engine 22 matches the reverse rotation lower limit threshold Nelimm. The state of setting a predetermined torque in the direction of reverse rotation of the engine 22 is maintained.

  When reverse rotation of the engine 22 is started and it is determined in step S210 that the rotation speed Ne of the engine 22 matches the lower limit threshold value Nelimm for reverse rotation, the rotation speed Ne of the engine 22 is set to a maximum value determined in advance by the performance of the motor MG1 or the like. The rate of increase is increased (step S220). For the increase in the rotation speed Ne of the engine 22 at the maximum increase rate, a torque for increasing the rotation speed Ne of the engine 22 at the allowable maximum increase rate is set in the torque command Tm1 * of the motor MG1 and transmitted to the motor ECU 40. This can be performed by controlling the switching of the switching element of the inverter 41 such that the motor ECU 40 outputs the torque corresponding to the torque command Tm1 * from the motor MG1.

  When the increase in the rotation speed Ne of the engine 22 at the maximum increase rate is started, a negative determination is made in step S210, and therefore the processing proceeds to step S230, where the rotation speed Ne of the engine 22 matches the upper threshold value Nelimp for forward rotation. It is determined whether or not. Now, since it is considered immediately after the increase of the rotation speed Ne of the engine 22 at the maximum increase rate is considered, the rotation speed Ne of the engine 22 does not match the upper limit threshold value Nelimp for normal rotation. In this case, the state in which the rotation speed Ne of the engine 22 is increased at the maximum increase rate, that is, the state in which the torque command Tm1 * of the motor MG1 is set to the predetermined torque for the maximum increase rate is maintained.

  When the rotation speed Ne of the engine 22 matches the upper limit threshold value Nelimp for normal rotation due to the increase of the rotation speed Ne of the engine 22 at the maximum increase rate, the rotation speed Ne of the engine 22 is held at the upper limit threshold value Nelimp for normal rotation ( (Step S240), this routine ends. To maintain the rotation speed Ne of the engine 22 at the upper limit threshold value Nelimp for normal rotation, the torque command Tm1 * of the motor MG1 is set by feedback control so as to cancel the difference between the rotation speed Ne of the engine 22 and the upper limit threshold value Nelimp for normal rotation. Then, it is transmitted to the motor ECU 40, and the switching control of the switching element of the inverter 41 is performed so that the motor ECU 40 outputs the torque corresponding to the torque command Tm1 * from the motor MG1.

  If the vehicle climbs over a step while executing the above-described reverse running control routine, the vehicle speed V becomes higher than the threshold value Vref, so a negative determination is made in step S120, and the normal reverse running control (EV The control at the time of reverse running in the running mode) is executed.

  FIG. 3 shows the dynamics of the rotational speed and torque in the rotating element of the planetary gear 30 when the rotational speed Ne of the engine 22 is increased by the motor MG1 from the lower limit threshold value Nelimm for reverse rotation to the upper limit threshold value Nelimp for normal rotation at the maximum rate of increase. It is explanatory drawing which shows an example of the alignment chart which shows this relationship. In the figure, the left S-axis indicates the rotation speed of the sun gear, which is the rotation speed Nm1 of the motor MG1, the C-axis indicates the rotation speed of the carrier, which is the rotation speed Ne of the engine 22, and the R-axis is the rotation speed Nm2 of the motor MG2. Shows the rotation speed Nr of the ring gear. Two thick arrows on the C-axis indicate the friction torque Tef of the engine 22 and the inertia torque Tei, and two thick-line arrows on the R-axis are output from the motor MG1 and act on the drive shaft 36 via the planetary gear 30. And the torque output from the motor MG2 and acting on the drive shaft 36. While the rotation speed Ne of the engine 22 is being increased at the maximum increase rate by the motor MG1, the engine 22 outputs the friction torque Tef according to the rotation speed and the inertia torque Tei for increasing the rotation speed Ne of the engine 22. Therefore, the torque output from the engine 22 to the drive shaft 36 via the planetary gear 30 and the negative rated torque Tm2rat2 output from the motor MG2 act on the drive shaft 36. FIG. 4 shows the torque Te of the engine 22 and the rotation speed Ne of the engine 22 when the rotation speed Ne of the engine 22 is increased by the motor MG1 from the lower limit threshold value Nelimm for reverse rotation to the upper limit threshold value Nelimp for forward rotation at the maximum increase rate. It is explanatory drawing which shows an example of a relationship. In the figure, the hatched portions (the third quadrant and the fourth quadrant) are used when the rotation speed Ne of the engine 22 is increased by the motor MG1 from the reverse rotation lower limit threshold Nelimm to the forward rotation upper limit threshold Nelimp at the maximum increase rate. It corresponds to the energy output from the engine 22. As shown in the figure, in the embodiment, the energy output from the engine 22 is higher than that in the case where the rotation speed Ne of the engine 22 is increased by the motor MG1 from the value 0 to the positive rotation upper limit threshold Nelimp at the maximum increase rate. The rotation speed Ne of 22 increases by the amount of energy in the negative region (third quadrant). As the amount of energy increases, the vehicle can overcome a higher step in the reverse direction.

  FIG. 5 is an explanatory diagram showing an example of temporal changes in the vehicle speed V, the motor torques Tm1, Tm2, the rotation speed Ne of the engine 22, and the like when riding over a step during reverse traveling. In the figure, the vehicle speed V, the accelerator opening Acc, the torque Tm2 of the motor MG2, the torque Tm1 of the motor MG1, the rotational speed Ne of the engine 22, and the counter C are shown in order from the top in the figure. When the vehicle speed V reaches a value of 0 due to a step at the time T1 during which the negative torque is output from the motor MG2 during reverse traveling, the driver depresses the accelerator pedal 83 at time T2 to get over the step. The accelerator opening Acc exceeds the threshold Aref, and the torque Tm2 of the motor MG2 increases to the negative side. The lock protection control is executed at time T3 when the torque output from the motor MG2 cannot overcome the step. The counter C is counted up from the time T4 when the lock protection control is released, and the reverse rotation of the engine 22 is started at the time T5 when the counter C reaches the threshold value Cref. Therefore, the torque for rotating the engine 22 in the reverse direction is output from the motor MG1, and the rotation speed Ne of the engine 22 increases to the negative side. At the time T5 when the rotation speed Ne of the engine 22 reaches the lower limit threshold value Nelimm for reverse rotation, a large torque for rotating the engine 22 to the forward rotation side is output from the motor MG1 in order to increase the rotation speed Ne of the engine 22 at the maximum increase rate. Then, the rotation speed Ne of the engine 22 increases. It is determined that the vehicle climbs over the step at time T7 when the rotation speed Ne of the engine 22 reaches the vicinity of the upper threshold value Nelimp for normal rotation, and the vehicle travels over the step at time T8 when the vehicle speed V becomes less than the threshold Vref, and the torque of the motor MG1 is determined. The value 0 is set to the command Tm1 *, and the rotation speed Ne of the engine 22 also decreases.

  In the hybrid vehicle 20 of the embodiment described above, when it is determined that the vehicle cannot get over the step during reverse traveling, the rotation speed Ne of the engine 22 is reduced to the reverse rotation lower limit threshold Nelimm, and then the normal rotation upper limit threshold is set at the maximum increase rate. By increasing the speed up to Nelimp, a larger amount of energy is applied to the drive shaft 36 as compared with the case where the rotation speed Ne of the engine 22 is increased from the value 0 to the upper limit threshold value Nelimp for forward rotation at the maximum increase rate. It is possible to get over a higher step.

  In the hybrid vehicle 20 of the embodiment, as the lower limit threshold value Nelimm for reverse rotation, the friction torque Tef of the engine 22 rotating in reverse matches the inertia torque Tei when the rotation speed Ne of the engine 22 is increased at the maximum increase rate. By using the rotation speed, unnecessary energy consumption can be suppressed.

  Although the embodiments for carrying out the present invention have been described above with reference to the embodiments, the present invention is not limited to these embodiments, and various embodiments are possible within the scope not departing from the gist of the present invention. Of course, it can be implemented.

  INDUSTRIAL APPLICABILITY The present invention can be used in the hybrid vehicle manufacturing industry and the like.

  20 hybrid vehicle, 22 engine, 23a crank position sensor, 24 engine electronic control unit (engine ECU), 26 crankshaft, 28 damper, 30 planetary gear, 36 drive shaft, 38 differential gear, 39a, 39b drive wheel, 40 for motor Electronic control unit (motor ECU), 41, 42 inverter, 43, 44 rotational position sensor, 50 battery, 51a voltage sensor, 51b current sensor, 51c temperature sensor, 52 battery electronic control unit (battery ECU), 54 power line, 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 a brake pedal position sensor, 88 vehicle speed sensor, MG1, MG2 motor.

Claims (1)

Engine,
A first motor,
A planetary gear in which a drive shaft connected to the first motor, the engine, and an axle is connected to a first rotating element, a second rotating element, and a third rotating element that are arranged in order in the alignment chart;
A second motor capable of outputting power to the drive shaft;
A control device that controls the engine, the first motor, and the second motor, and that determines a reverse step over when the vehicle cannot go over the step only by outputting an allowable maximum torque from the second motor during reverse traveling,
In a hybrid vehicle equipped with
When the control device determines that the reverse step is crossed, the second motor outputs the maximum allowable torque and the engine is rotated in the reverse rotation direction, and then the engine is rotated in the forward rotation direction. To control the first motor and the second motor so that
A hybrid vehicle characterized by the following.

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