JP2011046252A - Hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hybrid vehicle allowing quick retreat running in the event of trouble. <P>SOLUTION: The hybrid vehicle 20 includes: wheels; a lock mechanism 36 fixing the wheels; a motor MG2; an engine 22; a power dividing mechanism 30 transmitting torque from the motor MG2 and the engine 22 to driving shafts of the wheels; and a control unit 70 controlling the motor MG2 and the engine 22 and variably controlling the distribution ratio of the power dividing mechanism 30. The control unit 70 controls the power dividing mechanism 30 so as to transmit torque from the engine 22 to the wheels, putting the motor MG2 into a non-driving state, when a trouble occurs with the motor MG2 in the non-operating state of the lock mechanism 36, and the vehicle speed is larger than a predetermined value. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a hybrid vehicle, and more particularly to a hybrid vehicle configured to drive wheels using an engine and a motor.

  Japanese Patent Laid-Open No. 2008-290547 (Patent Document 1) discloses a hybrid vehicle that can output power more reliably when it is suspected that the rotation detection means of the electric motor that outputs power to the drive shaft is in an abnormal state. Disclosure.

  This hybrid vehicle detects the state of a rotational position detection sensor that detects the rotational state of motor generator MG2 when the system is activated. When it is not detected that the rotational position detection sensor is in the normal state, the motor generator MG1 and the engine are driven and controlled to start the engine. When it is detected that the rotational position detection sensor is in an abnormal state, the engine and motor generator MG1 are driven and controlled so that only the torque output from the engine via motor generator MG1 is output to the ring gear shaft. As described above, when it is suspected that the rotational position detection sensor is in an abnormal state, the engine may not be started after that, so that the power is output more reliably by starting the engine.

  Thus, even if there is a possibility that the motor generator MG2 has failed, the retreat travel can be performed by the torque from the engine.

JP 2008-290547 A JP 2008-168773 A JP 2006-250269 A

  However, the technique disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 2008-290547 only shows that an abnormality is detected when the system is activated, and processing when an abnormality is detected when the vehicle is stopped or running after the vehicle is activated. Is not specifically indicated.

  If the rotational state of the motor generator MG2 cannot be controlled when the shift range of the vehicle is other than the parking (P) range, the vehicle may move with the reaction force when the motor generator MG1 is started. For this reason, if the shift range is other than the P range, even if the vehicle is traveling, the vehicle cannot be evacuated unless the vehicle is temporarily stopped and the vehicle system is restarted.

  Even if a failure occurs during traveling, it is preferable to promptly retreat if possible.

  An object of the present invention is to provide a hybrid vehicle that can promptly retreat when a failure occurs.

  In summary, the present invention is a hybrid vehicle, which includes a wheel, a lock mechanism that fixes the wheel, a motor, an engine, a power split mechanism that transmits torque from the motor and the engine to a drive shaft of the wheel, and a motor. And a control device that controls the engine and variably controls the distribution ratio of the power split mechanism. The control device is a power split mechanism that causes the motor to be in a non-driving state and transmit torque from the engine to the wheels when an abnormality occurs in the motor when the lock mechanism is inactive and the vehicle speed is greater than a predetermined value. To control.

  Preferably, when the abnormality occurs in the motor and the vehicle speed is lower than a predetermined value and the engine is stopped, the control device waits until the lock mechanism is activated, and then starts the engine to turn off the motor. The power split mechanism is controlled so that the torque from the engine is transmitted to the wheels in the driving state.

  More preferably, the control device requests the driver to operate the lock mechanism when the abnormality occurs in the motor and the vehicle speed is lower than a predetermined value and the engine is stopped. When the requested operation is not performed, the operation of the vehicle is stopped.

  Preferably, the hybrid vehicle further includes a brake that applies a braking force to the wheels. When the abnormality occurs in the motor and the vehicle speed is lower than the predetermined value and the engine is stopped, the control device starts the engine after operating the brake, puts the motor in a non-driven state, The power split mechanism is controlled to transmit torque to the wheels.

  Preferably, the hybrid vehicle further includes a generator. The power split mechanism is configured such that three rotating shafts receive torque from the motor, the engine, and the generator. When the abnormality occurs in the motor and the vehicle speed is higher than a predetermined value, the control device splits the power so that the torque from the engine is transmitted to the wheels by controlling the rotation of the generator with the motor in a non-driven state. Control the mechanism.

  More preferably, the control device calculates the vehicle speed based on the rotational speed of the engine and the rotational speed of the generator.

  More preferably, the hybrid vehicle further includes a wheel speed sensor. The control device calculates the vehicle speed based on the output of the wheel speed sensor.

  More preferably, the hybrid vehicle further includes a wheel speed sensor. When an abnormality occurs in the motor, the control device compares the first vehicle speed calculated based on the rotational speed of the engine and the rotational speed of the generator with the second vehicle speed calculated based on the output of the wheel speed sensor. When the difference between the first and second vehicle speeds is smaller than the predetermined value, the engine is started. When the difference is larger than the predetermined value, the motor and the generator are not driven and the engine is operated until the difference becomes smaller than the predetermined value. Wait without starting.

  According to the present invention, it is possible to cause the hybrid vehicle to retreat quickly when a failure occurs.

It is a figure which shows the main structures of the hybrid vehicle 20 of this Embodiment. It is a flowchart for demonstrating the control about the start of the engine performed in this Embodiment, and the transfer to direct drive mode. It is a collinear diagram for demonstrating the relationship of the rotational speed of 3 axes | shafts of a power split device. It is a collinear chart for demonstrating the change of the rotational speed when starting an engine. FIG. 3 is a flowchart for illustrating an engine start process when the vehicle is stopped, which is executed in step S7 of FIG. It is a flowchart for demonstrating the modification of the engine starting process at the time of a vehicle stop.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

[Overall configuration of vehicle]
FIG. 1 is a diagram illustrating a main configuration of a hybrid vehicle 20 according to the present embodiment.

  Referring to FIG. 1, hybrid vehicle 20 includes an engine 22, a three-shaft power split mechanism 30 connected to crankshaft 26 that is an output shaft of engine 22 via damper 28, and power split mechanism 30. It includes a motor generator MG1 capable of generating power, a motor generator MG2 connected to power split mechanism 30, and an electronic control unit for hybrid 70 that controls 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 is in communication 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, if necessary, transmits data related to the operating state of the engine 22 to the hybrid electronic control. Output to unit 70.

  The power split 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, and a plurality of And a carrier 34 that holds the pinion gear 33 so as to rotate and revolve freely. The power split mechanism 30 is configured as a planetary gear mechanism that performs a differential action with the sun gear 31, the ring gear 32, and the carrier 34 as rotational elements.

  The crankshaft 26 of the engine 22 is connected to the carrier 34, and the motor generator MG1 is connected to the sun gear 31. When motor generator MG1 functions as a generator, power split mechanism 30 distributes the power from engine 22 input from carrier 34 to sun gear 31 side and ring gear 32 side according to the gear ratio. When motor generator MG1 functions as an electric motor, power split device 30 integrates the rotational force from engine 22 input from carrier 34 and the rotational force from motor generator MG1 input from sun gear 31 into ring gear 32 side. Output. The power output to the ring gear 32 is output from the rotating shaft of the ring gear 32 to the front wheels 39a and 39b via the gear mechanism 37 and the differential gear 38.

  A parking lock mechanism 36 is attached to the gear mechanism 37. The parking lock mechanism 36 includes a parking gear 36a attached to the final gear 37a, and a parking lock pole 36b that engages with the parking gear 36a and locks in a state where its rotational drive is stopped. The parking lock pole 36b moves up and down when a change signal to the parking position (P position) given by the shift lever 81 is transmitted via a shift cable (not shown). The parking lock pole 36b engages with the parking gear 36a and releases the parking lock and releases the parking lock.

  Since the final gear 37a is mechanically connected to the rotation shaft of the ring gear 32 as a drive shaft, the parking lock mechanism 36 indirectly locks the rotation shaft of the ring gear 32 as a drive shaft.

  As motor generator MG1 and motor generator MG2, a well-known synchronous generator motor that can be driven as an electric motor and driven as an electric motor can be used. Motor generators MG1, MG2 exchange power with battery 50 through inverters 41, 42.

  The power line 54 connecting the inverters 41 and 42 and the battery 50 includes a positive electrode bus and a negative electrode bus shared by the inverters 41 and 42. Thereby, the electric power generated by one of motor generators MG1 and MG2 can be consumed by another motor. Therefore, battery 50 is charged / discharged by electric power generated from motor generators MG1 and MG2 or insufficient electric power. It should be noted that battery 50 is not charged / discharged if the balance of power is balanced between motor generator MG1 and motor generator MG2.

  Hybrid vehicle 20 further includes an inverter 92, a motor generator MGR, a final gear 96, a differential gear 98, and rear wheels 99a and 99b. Inverter 92 drives motor generator MGR, and power of final gear 96 is output to rear wheels 99a and 99b via differential gear 98.

  Motor generators MG1, MG2, and MGR are all controlled by a motor electronic control unit (hereinafter referred to as motor ECU) 40. The motor ECU 40 receives signals necessary for driving and controlling the motor generators MG1, MG2, and MGR. These signals include, for example, signals from a resolver that detects the rotational speed of the rotors of the motor generators MG1, MG2, and MGR, and phase currents that are detected by a current sensor (not shown) and applied to the motor generators MG1, MG2, and MGR. Including. The motor ECU 40 outputs switching control signals to the inverters 41, 42, and 92.

  The motor ECU 40 calculates the rotational speeds Nm1 and Nm2 of the rotors of the motor generators MG1 and MG2 and the rotational speed Nr of the rotating shaft of the ring gear 32 by a rotational speed calculation routine (not shown) based on the signals input from the resolvers 43 and 44. Yes. The motor ECU 40 is in communication with the hybrid electronic control unit 70.

  The motor ECU 40 controls driving of the motor generators MG1, MG2, and MGR according to a control signal from the hybrid electronic control unit 70, and transmits data on the operation state of the motor generators MG1, MG2, and MGR as necessary. Output to 70.

  The rotation shaft 48 of the motor generator MG2 is connected to the rotation shaft of the ring gear 32. A reduction gear, a transmission capable of changing the reduction ratio, or the like may be provided between the rotation shaft 48 and the rotation shaft of the ring gear 32.

  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 from the temperature sensor 51 attached to the battery 50, and the like are input. Data regarding the state of the battery 50 is transmitted to the hybrid electronic control unit 70 by communication as necessary. The battery ECU 52 also calculates the remaining capacity (SOC) based on the integrated value of the charge / discharge current detected by the current sensor in order to manage the battery 50.

  The hybrid electronic control unit 70 is configured with a CPU 72 as a center, and in addition to the CPU 72, a flash ROM 74 capable of storing a processing program and writing information, a RAM 76 for temporarily storing data, and an input / output (not shown). A port and a communication port.

  The hybrid electronic control unit 70 is provided with 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 Acc corresponding to the amount of depression of the accelerator pedal 83. The accelerator opening Acc from the accelerator pedal position sensor 84 to be detected, the brake pedal position BP from the brake pedal position sensor 86 to detect the amount of depression of the brake pedal 85, the wheel speed from the wheel speed sensor 88, etc. via the input port. Have been entered.

  The hybrid electronic control unit 70 outputs a control signal to the parking lock mechanism 36. 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 communication ports, and exchanges various control signals and data with the engine ECU 24, the motor ECU 40, and the battery ECU 52. Is doing.

  In hybrid vehicle 20 having such a configuration, the required torque to be output to the rotating shaft of ring gear 32 as the drive shaft based on accelerator opening Acc and vehicle speed V corresponding to the amount of depression of accelerator pedal 83 by the driver. The engine 22, the motor generator MG1, and the motor generator MG2 are controlled so that the required power corresponding to the required torque is output to the rotating shaft of the ring gear 32.

  The travel mode of the hybrid vehicle 20 includes a torque conversion travel mode, a charge / discharge travel mode, a motor travel mode, a direct travel mode, and the like.

  In the torque conversion traveling 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 divided into the power split mechanism 30, the motor generator MG1, and the motor generator. Motor generator MG1 and motor generator MG2 are driven and controlled so that torque is converted by MG2 and output to the rotating shaft of ring gear 32.

  In the charge / discharge travel 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. The motor generator MG1 and the motor generator MG1 are configured such that all or part of the power output from the engine 22 is output to the rotating shaft of the ring gear 32 with torque conversion by the power split mechanism 30, the motor generator MG1, and the motor generator MG2. Motor generator MG2 is controlled.

  In the motor travel mode, operation of the motor generator MG2 is controlled so that the operation of the engine 22 is stopped and power corresponding to the required power from the motor generator MG2 is output to the rotating shaft of the ring gear 32.

  In the straight traveling mode, the operation of the motor generator MG2 is stopped, and the torque directly transmitted from the engine 22 to the rotating shaft of the ring gear 32 through the power split mechanism 30 while taking the reaction force of the engine torque by the motor generator MG1. Traveling is performed only with direct torque).

[Evacuation travel when motor generator MG2 fails]
When a failure related to motor generator MG2 is detected, retreating traveling can be performed by shifting to the direct traveling mode. However, if the vehicle is stopped such as waiting for a signal, the operation of the engine may be stopped.

  Under normal conditions, when the engine is started by the motor generator MG1 in such a case, the starting reaction force can be canceled by the motor generator MG2. However, when a failure related to motor generator MG2 has occurred, reaction force cannot be canceled, and therefore the vehicle may move in the direction opposite to the traveling direction when the engine is started. Therefore, when the vehicle is stopped, it is desirable to start the engine after the vehicle is in a stationary state such as a parking lock state.

  Further, if the vehicle is traveling at a predetermined vehicle speed or higher, there is an inertial force of the vehicle, so that the vehicle does not move in the direction opposite to the traveling direction due to the reaction force at the start of the engine. Therefore, the engine can be started even when the vehicle is not in a stationary state. However, since the rotational speed of the motor generator MG2 is measured with high accuracy, it is also used for calculating the vehicle speed. When a failure occurs in the resolver 44 that detects the rotational speed of the motor generator MG2, it is unclear whether or not the vehicle is stopped, and the situation cannot be detected even though the engine can be started.

  If the vehicle system must be stopped in such a case, it is inconvenient because even if the vehicle is traveling, the vehicle cannot be moved to retreat unless the vehicle is stopped. Therefore, in the present embodiment, when the engine can be started, the engine is started by grasping the situation by means other than the failed resolver.

  FIG. 2 is a flowchart for illustrating the control for engine start and transition to the straight running mode executed in the present embodiment. The processing of this flowchart is called and executed from a predetermined main routine every predetermined time or every time a predetermined condition is satisfied.

  Referring to FIG. 2, when the processing of this flowchart is started, it is determined in step S1 whether or not a motor generator MG2 system failure has occurred. The failure of the motor generator MG2 system is, for example, the failure of the resolver 44 in FIG. 1 or the failure of a sensor (not shown) that detects the current supplied from the inverter 42 to the motor generator MG2.

  If the motor generator MG2 system failure has not occurred in step S1, the process proceeds to step S12, and the control is moved to the main routine. On the other hand, if a motor generator MG2 system failure has occurred in step S1, the process proceeds to step S2.

  In step S2, the absolute value of the difference between the vehicle speed Vc calculated from the alignment chart based on the engine rotational speed Ne and the rotational speed Nm1 of the motor generator MG1 and the vehicle speed Vw calculated based on the output of the wheel speed sensor 88 is calculated. It is determined whether or not the value is smaller than a predetermined value A.

FIG. 3 is a collinear diagram for explaining the relationship between the rotational speeds of the three axes of the power split mechanism.
Referring to FIG. 3, the rotational speed Nm1 of motor generator MG1, the engine rotational speed Ne, and the rotational speed Nm2 of motor generator MG2 are respectively given to the three axes of the power split mechanism. Since the power split mechanism 30 uses a planetary gear mechanism, the rotational speed Ne of the engine 22 and the rotational speeds Nm1 and Nm2 of the motor generators MG1 and MG2 are linear as shown in the alignment chart shown in FIG. It moves in conjunction with each other.

Then, the relationship shown by the equation (1) is established among the engine rotation speed Ne, the rotation speed Nm1 of the motor generator MG1, and the rotation speed Nm2 of the motor generator MG2.
Ne = Nm1 × 1 / (1 + ρ) + Nm2 × ρ / (1 + ρ) (1)
From this equation, the rotational speed Nm2 of the motor generator MG2 can be calculated based on the rotational speed Nm1 of the motor generator MG1 and the rotational speed Ne of the engine 22.

  Usually, when the vehicle speed is constant, (a) the vehicle speed V obtained based on the output of the resolver 44 of the motor generator MG2, and (b) the formula (1) based on the rotational speed Nm1 and the engine rotational speed Ne of the motor generator MG1. The vehicle speed Vc calculated by using (c) and the vehicle speed Vw (wheel speed) show the same value. Here, when the resolver 44 of the motor generator MG2 fails, only the value of the vehicle speed V in (a) becomes unreliable.

  When such a failure is detected, the vehicle speed used for vehicle control is switched from the vehicle speed V obtained in (a) to the vehicle speed Vc obtained in (b). However, since the vehicle speed Vc is obtained by referring to a variable with a slow calculation cycle, it is necessary to end the predetermined time before returning to the normal vehicle speed after switching. When the deviation between the vehicle speed Vc obtained in (b) and the vehicle speed Vw obtained in (c) becomes smaller, it is considered that the vehicle speed Vc has been updated to a correct value, so this determination is made in step S2.

  If | Vc−Vw | <A is not satisfied in step S2, the vehicle speed Vc has not yet been updated to the correct value, so the process proceeds to step S9, and the engine is not started and the mode is not shifted to the GD mode. . In this case, it is determined in step S9 whether or not the engine is stopped. If the engine is stopped in step S9, the process proceeds to step S10, where the gates of the switching elements of the inverters 41 and 42 are shut down to an inactive state and wait. On the other hand, if the engine is not stopped in step S9, the process proceeds to step S11, and the motor generator MG1 is used to prevent the engine speed from decreasing so that the engine does not stop.

  If either step S10 or S11 is executed, the process proceeds to step S12, and control is transferred to the main routine.

  On the other hand, if | Vc−Vw | <A is satisfied in step S2, it is considered that the vehicle speed Vc has been updated to a correct value, and the process proceeds to step S3. In step S3, it is determined whether or not the engine is stopped. If it is determined in step S3 that the engine is stopped, the process proceeds to step S4. If the engine is not stopped, the process proceeds to step S8. In step S4, it is determined whether or not the shift range is the P range.

  In step S4, when the shift range is the P range, the wheel drive shaft is fixed by the parking lock mechanism 36, so there is no concern that the vehicle travels in the reverse direction due to the reaction force of the engine start. Therefore, the process proceeds from step S4 to step S6. In step S6, the hybrid electronic control unit 70 requests the engine ECU 24 and the motor ECU 40 to start the engine. The motor ECU 40 rotates the motor generator MG1 in order to crank the engine 22 while shutting down the inverter of the motor generator MG2 to make it non-driven.

FIG. 4 is a collinear diagram for explaining a change in rotational speed when the engine is started.
Referring to FIG. 4, when the vehicle is stopped (Nm2 = 0) and before the engine is started, engine rotational speed Ne (0) = 0 and rotational speed Nm1 (0) = 0 of motor generator MG1.

  The hybrid electronic control unit 70 requests the engine ECU 24 and the motor ECU 40 to start the engine. The motor ECU 40 shuts down the inverter of the motor generator MG2 so as not to be driven, and rotates the motor generator MG1 in order to crank the engine 22.

  If motor generator MG2 is normal, the reaction force generated on the rotating shaft of motor generator MG2 when driving motor generator MG1 when cranking engine 22 has been canceled by driving motor generator MG2.

  However, when an abnormality has occurred in motor generator MG2 system, this reaction force cannot be canceled. When the shift range is the P range, since the wheel drive shaft is fixed by the parking lock mechanism 36, there is no concern that the vehicle travels in the reverse direction due to the reaction force of the engine start. Therefore, the rotation speed of motor generator MG1 is increased to Nm1 (1). Then, the engine speed increases to Ne (1) by the action of the power split mechanism 30. Thereby, the engine 22 can be operated independently.

  Referring again to FIG. 2, if the shift range is not the P range in step S4, the process proceeds to step S5. In step S5, it is determined whether or not the absolute value of the vehicle speed Vc calculated from the nomograph is larger than a threshold value B (km / h). Here, the threshold value B is set to a value such that the inertial force of the vehicle exceeds the reaction force generated on the drive shaft when the engine is started. That is, if the vehicle is traveling at a speed higher than B (km / h), the vehicle will not move in the reverse direction even if the reaction force is not canceled by the motor generator MG2 when the engine is started. . In step S5, instead of using the vehicle speed Vc, the absolute value of the vehicle speed Vw calculated based on the output of the wheel speed sensor 88 may be changed to determine whether or not it is larger than the threshold value B. good.

  If | Vc |> B is satisfied in step S5, the process proceeds to step S6. In step S6, the hybrid electronic control unit 70 requests the engine ECU 24 and the motor ECU 40 to start the engine. The motor ECU 40 rotates the motor generator MG1 in order to crank the engine 22 while shutting down the inverter of the motor generator MG2 to make it non-driven.

  If | Vc |> B is not satisfied in step S5, the process proceeds to step S7. In step S7, an engine start process when the vehicle is stopped is executed.

  FIG. 5 is a flowchart for illustrating the engine start process when the vehicle is stopped, which is executed in step S7 of FIG.

  Referring to FIGS. 1 and 5, first, in step S101, it is determined whether or not HAC (hill start assist control) is usable. When starting on a steep hill or slippery hill surface, HAC starts off with the brake 60 being operated for a while even after the brake pedal 85 is stepped on and released, thereby relieving the backward movement of the vehicle. It is a function that makes it easier. If HAC can be used in step S101, the process proceeds to step S102.

  In step S102, the HAC is actuated (the brake is actuated even if the brake pedal is not depressed), thereby locking the wheel drive shaft and preventing the vehicle from moving in the reverse direction due to the reaction force when starting the engine. When the fixing of the driving wheel by the brake is completed in step S102, the process proceeds to step S108.

  On the other hand, if HAC is not usable in step S101, the process proceeds to step S103. In step S103, a message such as “Please set the shift lever to the parking position” is transmitted to the driver by voice or screen display. In step S104, it is determined whether or not the shift range has been changed to the P range.

  If the shift range is not yet the P range in step S104, the process proceeds to step S105. In step S105, it is determined whether X (seconds) has elapsed from the P range shift request in step S103. If X (seconds) has not yet elapsed, the process returns to step S104 to determine again whether or not the shift range has been changed to the P range. In step S105, if X (seconds) has elapsed, it is timed out, and in step S106, ReadyOff, that is, the power of the vehicle system is temporarily turned off. In this case, the power of the vehicle system is turned off and the shift range is also moved to the P range. Therefore, if the driver restarts the engine, the engine can be started with the shift range set to the P range.

  If the shift to the P range has been confirmed in step S104, the process proceeds to step S108.

  In step S108, since the brake is operating or the parking lock mechanism is working, there is no fear that the vehicle moves in the reverse direction. Therefore, the hybrid electronic control unit 70 requests the engine ECU 24 and the motor ECU 40 to start the engine. The motor ECU 40 rotates the motor generator MG1 in order to crank the engine 22 while shutting down the inverter of the motor generator MG2 to make it non-driven.

  When the engine start is completed in step S108, the process proceeds to the flowchart of FIG. 2 in step S109.

  Referring to FIG. 2 again, if NO in step S3 (that is, if the engine is operating) and if the engine is started in step S6 or step S7, the GD mode is entered in step S8. Transition takes place.

  The GD mode is a straight traveling mode, in which the operation of the motor generator MG2 is stopped, and the motor generator MG1 receives the reaction force of the engine torque from the engine 22 to the rotating shaft of the ring gear 32 through the power split mechanism 30. Traveling is performed only with the directly transmitted torque.

  When the transition process in step S8 is completed, control is transferred to the main routine in step S12.

  The engine start process in the flowchart of FIG. 5 described above is a vehicle (a vehicle that drives only the front wheels) in which the motor generator MGR that drives the rear wheels is not mounted in the configuration of the vehicle shown in FIG. Can also be applied.

  Next, a modification in which the motor generator MGR is also used for canceling the reaction force at the start will be described.

  FIG. 6 is a flowchart for explaining a modification of the engine start process when the vehicle is stopped.

  The process of the flowchart shown in FIG. 6 is executed as step S7A instead of step S7 in FIG. In addition to the process of step S7 shown in FIG. 5, the processes of steps S201 and S202 are added to the process of the flowchart shown in FIG. Since the processing in steps S101 to S108 is the same as that described in FIG. 5, the description thereof will not be repeated here.

  First, when the process of step S7A is started, it is determined in step S201 whether or not the motor generator MGR of FIG. 1 is usable. If the motor generator MGR is usable in step S201, the process proceeds to step S202, and if not usable, the process proceeds to step S101.

  When the process proceeds to step S101, the processes of steps S101 to S108 similar to those in FIG.

  When the process proceeds to step S202, the hybrid electronic control unit 70 requests the engine ECU 24 and the motor ECU 40 to start the engine. The motor ECU 40 rotates the motor generator MG1 in order to crank the engine 22 while shutting down the inverter of the motor generator MG2 to make it non-driven. At the same time, motor ECU 40 drives motor generator MGR to cancel the reaction force of motor generator MG1. If torque is generated in the forward direction in the motor generator MGR that drives the rear wheels, even if reaction torque is generated in the reverse direction in the front wheels, both can be canceled, so that the vehicle can be prevented from moving backward.

  Thereby, even when the engine is stopped, the engine can be started to shift to the straight traveling mode (GD mode).

[Operation example]
Consider a case where a failure has occurred in motor generator MG2 while decelerating from a vehicle speed of 80 km / h to a vehicle speed of 40 km / h. At the time of deceleration, the engine rotation speed moves to the stop side, so that the engine 22 is started after the failure is detected (for example, the disconnection of the resolver 44, etc.). Immediately after the failure is detected, the vehicle speed V (ECU-recognized vehicle speed) calculated from the rotational speed of the motor generator MG2 is an unreliable value. For example, the actual vehicle speed is 40 km / h, but the vehicle speed calculated from the output of the resolver 44 is 3 km / h. Therefore, the vehicle speed calculation method is switched to a method using a nomograph, and the vehicle speed Vc is calculated. However, since the response is somewhat slow, it takes, for example, 1 second until the vehicle speed Vc reaches the actual vehicle speed.

  As a method of detecting this delay, | Vw−Vc | is monitored in step S2 of FIG. 2, and if this difference becomes smaller than A (for example, 1 km / h), Vc is regarded as an actual vehicle speed, and according to the vehicle speed. To go straight mode. If the difference is greater than or equal to A, if the engine 22 has not been started, the inverter gate is shut down and the vehicle speed Vc is awaited to become the actual vehicle speed with the driving force cut off. When the difference is greater than or equal to A and the engine 22 is starting, the motor generator MG1 maintains the engine speed at a certain value or higher in order to prevent the engine from stopping.

  After the ECU-recognized vehicle speed becomes the actual vehicle speed, if the ECU-recognized vehicle speed is higher than a threshold value B (for example, 3 km / h) (YES in step S5), the engine is started and immediately shifts to the straight running mode.

  After the ECU recognized vehicle speed becomes the actual vehicle speed, if the ECU recognized vehicle speed is lower than a threshold value B (for example, 3 km / h) (NO in step S5), after performing the engine start process (step S7) when the vehicle is stopped Transition to the straight running mode.

  In the vehicle stop engine start process, if the vehicle is a four-wheel drive vehicle, the reaction force torque that travels in the reverse direction when the engine is started is canceled by the torque of the motor generator MGR (step S102), and the mode is shifted to the direct drive mode. If the vehicle is a two-wheel drive vehicle, HAC is used to prevent reverse travel, and the engine is started to shift to the straight travel mode. If HAC cannot be used, a message “Please enter P range” is displayed (step S103), and the engine is started in the P range.

[Summary]
Finally, the present embodiment will be summarized with reference to the drawings again. For the sake of simplicity, motor generator MG1 that operates mainly as a generator is referred to as generator MG1, and motor generator MG2 that operates primarily as an electric motor is referred to as motor MG2.

  1 and 2, hybrid vehicle 20 transmits a wheel, a lock mechanism 36 for fixing the wheel, motor MG2, engine 22, and torque from motor MG2 and engine 22 to the drive shaft of the wheel. And a control unit 70 that controls the motor MG2 and the engine 22 and variably controls the distribution ratio of the power split mechanism 30. The control unit 70 is in a case where an abnormality has occurred in the motor MG2 when the lock mechanism 36 is in an inoperative state, and when the vehicle speed is greater than a predetermined value (Bkm / h) (YES in step S5), the motor MG2 is in a non-driven state The power split mechanism 30 is controlled so as to transmit the torque from the engine 22 to the wheels (step S8).

  Preferably, control unit 70 is in the case where an abnormality has occurred in motor MG2, and when vehicle speed is smaller than a predetermined value (Bkm / h) and engine 22 is stopped (YES in step S3 and NO in step S5). After waiting until the lock mechanism 36 is activated (YES in step S104), the engine 22 is started (step S108), and the motor MG2 is set in a non-driven state to transmit the torque from the engine 22 to the wheels. 30 is controlled (step S8).

  More preferably, as shown in FIGS. 2 and 5, the control unit 70 is a case where an abnormality has occurred in the motor MG2 (YES in step S1), and the vehicle speed Vc is smaller than a predetermined value (Bkm / h) and When the engine 22 is stopped (YES in step S3 and NO in step S5), the driver is requested to operate the lock mechanism 36 (step S103), and when the operation requested by the driver is not performed (step S103). S105), the operation of the vehicle is stopped (step S106).

  Preferably, the hybrid vehicle 20 further includes a brake 60 that applies a braking force to the wheels. As shown in FIGS. 2 and 5, the control unit 70 is a case where an abnormality has occurred in the motor MG2 (YES in step S1), the vehicle speed Vc is smaller than a predetermined value (Bkm / h), and the engine 22 is stopped. (YES in step S3 and NO in step S5), the brake 60 is operated and then the engine 22 is started (steps S102 and S108), the motor MG2 is deactivated, and the torque from the engine 22 is applied to the wheels. The power split mechanism 30 is controlled to transmit (step S8).

  Preferably, hybrid vehicle 20 further includes a generator MG1. Power split device 30 is configured such that three rotating shafts receive torque from motor MG2, engine 22, and generator MG1. When an abnormality has occurred in motor MG2 and the vehicle speed is greater than a predetermined value (YES in step S1 and YES in step S5), control unit 70 sets motor MG2 in a non-driven state and controls the rotation of generator MG1. Thus, the power split mechanism 30 is controlled so as to transmit the torque from the engine 22 to the wheels (step S8).

  More preferably, the control unit 70 calculates the vehicle speed based on the rotational speed Ne of the engine 22 and the rotational speed Nm1 of the generator MG1 using the relationship of FIG.

  More preferably, the hybrid vehicle 20 further includes a wheel speed sensor 88. The control unit 70 calculates the vehicle speed based on the output of the wheel speed sensor 88.

  More preferably, the hybrid vehicle 20 further includes a wheel speed sensor 88. The control unit 70 calculates the first vehicle speed Vc calculated based on the rotational speed of the engine 22 and the rotational speed of the generator MG1 and the output of the wheel speed sensor 88 when an abnormality occurs in the motor MG2. When the difference between the first and second vehicle speeds is smaller than the predetermined value (YES in step S2), the engine 22 is started (FIG. 2: step S6 or step S7), and the difference is predetermined. If it is greater than the value (NO in step S2), the motor and generator MG1 are set in a non-driven state, and the engine 22 is not started until the difference becomes smaller than a predetermined value (FIG. 2: steps S9 to S11).

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  20 hybrid vehicle, 22 engine, 24 engine ECU, 26 crankshaft, 28 damper, 30 power split mechanism, 31 sun gear, 32 ring gear, 33 pinion gear, 34 carrier, 36 parking lock mechanism, 36a parking gear, 36b parking lock pole, 37 Gear mechanism, 37a, 96 Final gear, 38, 98 Differential gear, 39a, 39b Front wheel, 40 Motor ECU, 41, 42, 92 Inverter, 43, 44 Resolver, 48 Rotating shaft, 50 Battery, 51 Temperature sensor, 52 Battery ECU , 54 Power line, 60 Brake, 70 Hybrid electronic control unit, 72 CPU, 74 Flash 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 Wheel speed sensor, 99a, 99b Rear wheel, MG1, MG2, MGR Motor generator.

Claims (8)

Wheels,
A lock mechanism for fixing the wheel;
A motor,
Engine,
A power split mechanism for transmitting torque from the motor and the engine to a drive shaft of the wheel;
A controller for controlling the motor and the engine and variably controlling a distribution ratio of the power split mechanism;
The control device is configured to cause the motor to be in a non-driven state and transmit torque from the engine to the wheels when an abnormality occurs in the motor when the lock mechanism is in an inoperative state and the vehicle speed is higher than a predetermined value. A hybrid vehicle that controls the power split mechanism.   When the abnormality occurs in the motor and the vehicle speed is lower than a predetermined value and the engine is stopped, the control device waits until the lock mechanism is activated before starting the engine, The hybrid vehicle according to claim 1, wherein the power split mechanism is controlled so that a motor is in a non-driven state and torque from the engine is transmitted to the wheels.   When the abnormality occurs in the motor and the vehicle speed is lower than a predetermined value and the engine is stopped, the control device requests the driver to operate the lock mechanism. The hybrid vehicle according to claim 2, wherein the operation of the vehicle is stopped when the requested operation is not performed. A brake for applying braking force to the wheel;
When an abnormality occurs in the motor, and the vehicle speed is lower than a predetermined value and the engine is stopped, the control device activates the brake and then starts the engine to turn off the motor. The hybrid vehicle according to claim 1, wherein the power split mechanism is controlled so as to be in a driving state and transmit torque from the engine to the wheels. A generator,
The power split mechanism is configured such that three rotating shafts receive torque from the motor, the engine, and the generator,
When the abnormality occurs in the motor and the vehicle speed is higher than a predetermined value, the control device sets the motor to a non-driven state and controls the rotation of the generator to thereby apply torque from the engine to the wheels. The hybrid vehicle according to claim 1, wherein the power split mechanism is controlled to transmit.   The hybrid vehicle according to claim 5, wherein the control device calculates the vehicle speed based on a rotational speed of the engine and a rotational speed of the generator. A wheel speed sensor,
The hybrid vehicle according to claim 5, wherein the control device calculates the vehicle speed based on an output of the wheel speed sensor. A wheel speed sensor,
The control device, when an abnormality occurs in the motor, the first vehicle speed calculated based on the rotational speed of the engine and the rotational speed of the generator, and a second calculated based on the output of the wheel speed sensor The engine is started when the difference between the first and second vehicle speeds is smaller than a predetermined value, and when the difference is larger than the predetermined value, the motor and the generator are set in a non-driven state. The hybrid vehicle according to claim 5, wherein the hybrid vehicle waits without starting the engine until the difference becomes smaller than the predetermined value.

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