JP4682920B2 - VEHICLE POWER DEVICE AND CONTROL DEVICE THEREOF - Google Patents

Description

  The present invention relates to a vehicle power device having a flyhole that can be connected to and disconnected from an output shaft of an engine, and more particularly to control for connecting and disconnecting a flywheel.

  Generally, a flywheel is connected to a crankshaft, which is an output shaft of an engine, for reducing engine rotational fluctuation. Increasing the flywheel's moment of inertia reduces rotational fluctuations, and is particularly effective in engine idling and low-speed operation. On the other hand, when the inertial moment of the flywheel is large, energy is consumed to accelerate the flywheel during vehicle acceleration, and the acceleration performance of the vehicle decreases. In addition, when the vehicle is decelerated, the engine brake is less effective due to the energy stored in the flyhole.

  In order to satisfy the conflicting demands of reducing rotational fluctuation at low speed and improving responsiveness at acceleration / deceleration, a flywheel capable of changing the moment of inertia has been proposed. In the following Patent Document 1, a technique is disclosed in which a first flywheel coupled to an engine crankshaft and a second flywheel that can be connected to and disconnected from the first flywheel are provided. In this technique, when idling, the second flywheel is engaged with the first flywheel to increase the moment of inertia coupled to the crankshaft, and when accelerating, it is separated to reduce the moment of inertia. ing.

JP 2003-74641 A

  An engine mounted on a vehicle may perform so-called fuel cut control in which fuel supply is cut off when engine output is not required. When the fuel cut is performed, the engine output fluctuates greatly before and after the fuel cut, so that vibration is generated and transmitted to the vehicle body, and the vehicle occupant may feel this. In the above-mentioned Patent Document 1, although attention is paid to vibration when the second flywheel is connected, control related to the engine body, particularly vibration in fuel cut control, and countermeasures thereof are not described.

  An object of the present invention is to reduce vibration generated during fuel cut by using a flywheel that can be connected to and disconnected from an output shaft of an engine.

  In order to solve the above-described problems, a vehicle power device according to the present invention includes an engine, a flywheel that can be connected to and disconnected from the output shaft of the engine, an engine control, and a flywheel connection and disconnection control. A control unit that performs the control of cutting the flywheel after a predetermined time has elapsed after the fuel supply is stopped when the engine is stopped.

  Alternatively, when the engine is stopped, the control unit may execute control for cutting the flywheel after the engine rotation speed has decreased by a predetermined value after the supply of fuel is stopped.

  Alternatively, when the engine is stopped, the control unit may execute control for cutting the flywheel after the fuel supply is stopped and the vibration by the vibration detection unit is reduced to a predetermined level.

  This vehicle power unit can be mounted on a hybrid vehicle having an engine and a motor as a prime mover.

  In addition, a control device for a vehicle power device according to another aspect of the present invention controls a vehicle power device having an engine that drives the vehicle and a flywheel that can be connected to and disconnected from the output shaft of the engine. An engine stop control unit that controls to stop the engine by stopping the supply of fuel to the engine, and a control to cut the flywheel after a predetermined time has elapsed since the fuel supply was stopped And a flywheel cutting control unit for performing.

  Or a flywheel cutting | disconnection control part shall perform control which cut | disconnects a flywheel after the rotation speed of an engine falls by a predetermined value after supply of fuel is cut off.

  Alternatively, the flywheel cutting control unit acquires the vibration level of a predetermined part of the vehicle after a predetermined time has elapsed after the fuel supply is established, and cuts the flywheel after the acquired vibration level has decreased to the predetermined level. It is possible to perform control.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a schematic configuration of a power device 10 for a hybrid vehicle according to the present embodiment. The power unit 10 includes an engine 12 as a prime mover for driving the vehicle, and first and second motors 14 and 16 capable of generating electric power. These prime movers are respectively connected to the three elements of the planetary gear mechanism constituting the power distribution and integration mechanism 18. That is, the engine 12 is connected to the planetary carrier 20 of the planetary gear mechanism, the first motor 14 is connected to the sun gear 22, and the second motor 16 is connected to the ring gear 24. An output gear 26 is connected to the ring gear 24, and power obtained by integrating the outputs of the prime movers from the output gear 26 is supplied to the drive wheels 34 via the reduction gear train 28, the differential device 30 and the drive shaft 32. Communicated.

  A power distribution and integration mechanism 18 is provided, and the vehicle is driven by the engine 12 and the second motor 16 by controlling the rotational speed and output torque of the engine 12 and the first and second motors 14 and 16. The power unit 10 can perform various modes of operation, such as driving one motor 14 to generate power, or generating regenerative power with the second motor 16 by rotational force from the drive wheels 34 due to vehicle inertia. It has become.

  The first motor 14 and the sun gear 22 are directly coupled via the output shaft of the first motor 14. On the other hand, the second motor 16 is connected to the ring gear 24 via the speed reduction mechanism 36. The speed reduction mechanism 36 can adopt a planetary gear mechanism, and the output shaft of the second motor 16 is connected to the sun gear, and the ring gear 24 of the power distribution and integration mechanism is connected to the ring gear. The planetary carrier is fixed, whereby the rotation of the second motor 16 is decelerated and transmitted to the output gear 26.

  The engine 12 and the planetary carrier 20 are connected via a torsion damper 38. Further, a flywheel 42 for storing rotational energy is provided via a clutch 44 between the engine 12 and the torsion damper 38 of the engine output shaft 40. This flywheel 42 is different from a general flywheel, that is, a flywheel that is coupled to an engine crankshaft and rotates together with the flywheel 42. In order to distinguish these, the flywheel 42 is added hereinafter. This is referred to as the flywheel 42. The additional flywheel 42 may be configured to be connected to and disconnected from the engine output shaft by providing a clutch between the additional flywheel 42 and a normal flywheel, and connecting and disconnecting the clutch.

  The additional flywheel 42 can be connected to and disconnected from the engine output shaft 40 by a clutch 44. When the engine 12 is rotating, the clutch 44 is brought into a connected state, and the additional flywheel 42 is rotationally driven by the prime mover such as the engine 12 or the inertia of the vehicle to store rotational energy. When the rotational speed of the engine becomes lower than a predetermined value or when the engine is stopped, the clutch 44 is disengaged and the additional flywheel 42 is kept rotated. When the engine 12 is restarted, the energy stored in the additional flywheel 42 is used. That is, when the engine 12 is restarted, the clutch 44 is connected and the engine output shaft 40 is rotated. At this time, the first motor 14 can also rotate the engine 12.

  Further, in a state where the additional flywheel 42 is connected to the engine output shaft 40, the moment of inertia of the rotating system of the engine 12 increases, the rotational fluctuation of the engine 12 can be reduced, and vibration noise is reduced. effective. In addition, when the additional flywheel 42 is disconnected from the engine output shaft 40, the moment of inertia is reduced, and there is an effect of improving the responsiveness when the engine is accelerated.

  The first and second motors 14 and 16 are connected to the battery 50 via first and second inverters 46 and 48, respectively. The electric power stored in the battery 50 is converted into alternating current by the first and second inverters 46 and 48 and supplied to the first and second motors 14 and 16 to drive them. The electric power generated by the first and second motors 14 and 16 is converted into direct current or pulsating current by the first and second inverters 46 and 48 and sent to the battery 50 where it is stored.

  In order to detect the rotational speeds of the engine 12, the first and second motors 14 and 16, and the additional flywheel 42, rotational speed sensors 52, 54, 56, and 58 are provided, respectively. The engine rotation speed sensor 52 sends a rotation speed signal to an engine electronic control unit (engine ECU) 60. The engine ECU 60 controls the engine rotation speed and output torque based on this signal and other signals related to engine control. To do. The rotation speed sensors 54 and 56 of the first and second motors 14 and 16 send a rotation speed signal to the motor ECU 62, and the motor electronic control unit (motor ECU) 62 outputs the rotation speed and output of the motor based on this signal and the like. Control torque. Further, a battery electronic control unit (battery ECU) 64 is provided to control the amount of power stored in the battery 50 and the like. These ECUs 60, 62, 64 are connected to a higher-level hybrid electronic control unit (hybrid ECU) 66. The hybrid ECU 66 receives a signal reflecting the driver's intention, such as wanting to accelerate or decelerate, from the ignition switch 68, the accelerator pedal 70, the brake pedal 72, the shift lever 74, and the like operated by the driver. Further, a signal from a vehicle speed sensor 76 for detecting the traveling speed of the vehicle is also input. It should be noted that the signal from the vehicle speed sensor 76 can be substituted by acquiring the rotational speed of the second motor 16 via the motor ECU 62.

  The hybrid ECU 66 determines a driver's request based on a signal from an operator such as the accelerator pedal 70 operated by the driver, and on the other hand, a vehicle based on information from each of the ECUs 60, 62, 64 and the vehicle speed sensor 76. The ECU is instructed to perform the driving applied to the driver's request and the vehicle state. The hybrid ECU 66 also performs control related to the additional flywheel 42 based on the driver's request and the state of the vehicle.

  The operation of the additional flywheel 42 will be described in more detail. In the power unit 10, it is not necessary to charge the battery 50 when the vehicle is temporarily stopped due to a signal or the like, or when the vehicle speed is low and the efficiency of the engine 12 is low. Is satisfied, the engine 12 is temporarily stopped. When a predetermined condition is satisfied, for example, when the vehicle speed exceeds a predetermined vehicle speed from such a temporary stop state, the hybrid ECU 66 performs control related to engine restart. In order to distinguish the start at this time from the start based on the operation of the ignition switch 68, it will be referred to as restart hereinafter. In the power unit 10, the restart is performed by the energy stored in the additional flywheel 42 and the output of the first motor 14.

  When the hybrid ECU 66 determines that the conditions for engine restart have been satisfied, the engine ECU 60 and the motor ECU 62 are instructed to execute predetermined control of the engine 12 and the motor, particularly the first motor 14. Also, connection control of the clutch 44 is performed in synchronization with the control of the engine 12 and the first motor 14. Therefore, the hybrid ECU 66, the engine ECU 60, and the motor ECU 62 function as a control unit that controls the operation of the engine and the motor and the clutch that connects and disconnects the additional flywheel 42.

  As described above, the power plant 10 of the present embodiment stops the engine when a predetermined condition is satisfied. When the hybrid ECU 66 determines that the conditions for stopping the engine are satisfied, the hybrid ECU 66 instructs the engine ECU 60 to stop the engine. The engine ECU 60 stops supplying fuel (fuel cut) and stops supplying power to the spark plug. As a result, the engine 12 stops. On the other hand, the hybrid ECU 66 disengages the clutch 44 and controls the additional flywheel 42 to continue rotating. The energy stored in the rotating storage energy fly hole 42 can be used at the time of restart. The disconnection of the clutch 44 at this time is executed with a delay after the fuel cut. The delay amount after the fuel cut may be determined based on time, or may be determined based on the decreased engine speed. When based on time, the clutch 44 is disengaged after a predetermined time has elapsed since the fuel cut. Further, when based on the engine rotational speed, the clutch 44 is disconnected after a predetermined rotational speed is reduced from the engine rotational speed at the time of fuel cut. Therefore, at the time of the fuel cut, the moment of inertia of the engine rotation system is maintained at a large level, and the rotation fluctuation due to the torque fluctuation before and after the fuel cut can be suppressed. Then, when the engine has not yet stopped, the clutch 44 is disconnected, and the rotation of the additional flywheel 42 is maintained.

  FIG. 2 shows a time chart showing the relationship among the rotational speed 100 of the additional flywheel 42 when the engine 12 is stopped, the rotational speed 102 of the engine 12, the fuel supply signal 104, and the clutch control signal 106.

  When the engine 12 is controlled to stop, the fuel supply signal is changed from on (ON) to off (OFF) (time t1). By this control, the fuel supply is cut off, and the engine speed 102 starts to decrease. Before the fuel cut, the additional flywheel 42 is connected to the clutch 44 and is rotated integrally with the output shaft 40 of the engine 12. Even at the time t1 when the fuel is cut, the clutch is on (ON), and the rotational speed of the additional flywheel 42 starts to decrease together with the engine 12. At this time, the moment of inertia of the rotation system of the engine 12 is in a large state, and the rotation fluctuation due to the torque change before and after the fuel cut can be suppressed.

  At a time t2 when a predetermined time has elapsed from the fuel cut start time t1, a control for disengaging the clutch 44 is performed. This disconnection is performed quickly so that the clutch slips for a short time. After the clutch 44 is disengaged, the rotational speed of the engine 12 decreases and finally stops. On the other hand, the additional flywheel 42 maintains the rotational speed at the time t2 when the clutch 44 is disengaged, and prepares for the next engine restart. The time from time t1 to time t2 is set to such a time that vibration during fuel cut can be suppressed and the rotational speed of the additional flywheel 42 is as high as possible. In practice, the shortest time is selected within the allowable range of vibration level.

  The power unit 10 of the present embodiment includes an engine and a motor as a prime mover, and can stop the engine even during traveling and can be driven by the motor. Therefore, the engine stop control is performed relatively frequently, but the vibration due to the fuel cut at that time can be reduced. Further, even in a vehicle having only an engine as a prime mover, for example, an additional flywheel similar to the present embodiment and its control is also used in a vehicle that automatically stops the engine when idling such as when waiting for a signal and restarts when starting. Can be adopted.

  In the above embodiment, the clutch is disengaged with a delay based on the time from the fuel cut time, the engine speed, and the like. However, instead of performing a predetermined amount of delay, the clutch can be disengaged after the actual problem due to the fuel cut is eliminated. Specifically, the clutch is disengaged when the vibration generated by the fail cut reaches a level that does not cause a problem. The vibration can be detected, for example, as vibration at a rotational speed by an engine rotational speed sensor. Further, it is possible to detect the vibration of the vehicle body, which is a part of the vehicle other than the power device such as the engine, by providing a sensor.

It is a schematic block diagram of the power plant which concerns on this embodiment. It is a time chart which shows the change of the rotational speed of an additional flywheel when stopping an engine, an engine rotational speed, a clutch control signal, and a fuel supply signal.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Power unit, 12 Engine, 14 1st motor, 16 2nd motor, 18 Power distribution integrated distribution mechanism, 40 Engine output shaft, 42 Additional flywheel, 44 Clutch.

Claims (7)

An engine that drives the vehicle;
A flywheel that can be connected to and disconnected from the engine output shaft;
A control unit for controlling the engine and connecting / disconnecting the flywheel;
Have
The control unit may cut off the supply of fuel after the instruction of engine stop, after a standing supply of fuel predetermined time, and cut control flywheel when the flywheel is still spinning,
Suppresses the vibration of the engine due to the fuel supply stop by delaying the flywheel cutting from the fuel supply stop.
Vehicle power unit. An engine that drives the vehicle;
A flywheel that can be connected to and disconnected from the engine output shaft;
A control unit for controlling the engine and connecting / disconnecting the flywheel;
Have
The control unit may cut off the supply of fuel after the instruction of engine stop, after the engine rotational speed from the standing fuel supply is decreased a predetermined value, the flywheel when the flywheel is still spinning Cutting control and
Suppresses the vibration of the engine due to the fuel supply stop by delaying the flywheel cutting from the fuel supply stop.
Vehicle power unit. An engine that drives the vehicle;
A flywheel that can be connected to and disconnected from the engine output shaft;
A control unit for controlling the engine and connecting / disconnecting the flywheel;
A vibration detection unit for detecting vibration of a predetermined part of the vehicle;
Have
When the engine is stopped, the control unit cuts off the flywheel after the vibration by the vibration detection unit is reduced to a predetermined level after the supply of fuel is stopped.
Vehicle power unit.   4. The vehicle power device according to claim 1, wherein the vehicle power device is mounted on a hybrid vehicle having an engine and a motor as a prime mover. 5. A control device for controlling a vehicle power unit having an engine that drives a vehicle and a flywheel that can be connected to and disconnected from an output shaft of the engine,
An engine stop control unit for controlling the engine to stop by stopping the fuel supply to the engine;
A flywheel cutting control unit that performs control to cut the flywheel when the flywheel is still rotating after a predetermined time has elapsed after the fuel supply is cut off;
I have a,
A control device for a vehicular power unit that suppresses engine vibration caused by fuel supply stoppage by delaying flywheel cutting from fuel supply stoppage . A control device for controlling a vehicle power unit having an engine that drives a vehicle and a flywheel that can be connected to and disconnected from an output shaft of the engine,
An engine stop control unit for controlling the engine to stop by stopping the fuel supply to the engine;
A flywheel cutting control unit for controlling the flywheel to be cut when the flywheel is still rotating after the engine rotation speed is reduced by a predetermined value after the fuel supply is cut off;
I have a,
A control device for a vehicle power unit that suppresses engine vibration caused by stopping fuel supply by delaying flywheel cutting from stopping fuel supply . A control device for controlling a vehicle power unit having an engine that drives a vehicle and a flywheel that can be connected to and disconnected from an output shaft of the engine,
An engine stop control unit for controlling the engine to stop by stopping the fuel supply to the engine;
A flywheel cutting control unit that acquires a vibration level of a predetermined part of the vehicle after a lapse of a predetermined time since the fuel supply is cut off, and performs control for cutting the flywheel after the acquired vibration level is reduced to the predetermined level. When,
A control device for a vehicle power unit.

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