JP4697041B2 - VEHICLE POWER DEVICE AND CONTROL DEVICE THEREOF - Google Patents

Description

  The present invention relates to a vehicular power unit that accumulates rotational energy and uses this energy when starting an engine, and more particularly, relates to control when starting the engine.

  2. Description of the Related Art There is known an engine restart device that rotates a flywheel to store energy and uses the stored energy to start the engine. For example, in Patent Document 1 below, a flywheel is rotated by a motor before the engine is restarted, and the engine is cranked and started based on rotational energy stored in the flywheel and the output of the motor. Technology is disclosed. Further, in Patent Document 2 below, when the vehicle is running, the flywheel is rotated by the output of the engine, the vehicle is stopped and the engine is stopped. The technology to be used is disclosed.

JP 2002-48036 A (paragraphs 0069-0070, etc.) Microfilm of actual application No. 56-142534

  In the technology described in the patent document, it is not considered how much energy is stored in the flywheel when the engine is restarted. Therefore, when the stored energy is low, the energy required for restarting the engine cannot be obtained, and when a large amount of energy is stored, the engine rotates rapidly when restarting, causing vibration and shock. There is a problem of doing.

  An object of the present invention is to suppress generation of vibrations and shocks when restarting an engine using energy stored in a flywheel.

  In order to solve the above-described problem, a vehicle power device of the present invention includes a motor used for starting an engine, a flywheel that accumulates energy by rotating, and that can be connected to and disconnected from an output shaft of the engine, A rotation speed sensor that detects the rotation speed of the flywheel, and a control unit that controls connection and disconnection of the engine, motor, and flywheel. The cranking is performed by the energy accumulated in the wheel, and the control unit changes the cranking output by the motor according to the detected rotational speed of the flywheel when starting the engine.

  Furthermore, the said control part shall change a cranking output by changing the output torque of a motor.

  Moreover, the said control part shall change a cranking output by changing the time for which a motor rotates.

  Further, the power device is a power device of a hybrid vehicle, and the motor can be a motor used for driving or power generation of the vehicle.

  In addition, the control device for a vehicle power unit according to another aspect of the present invention stores energy by rotating an engine, a motor used for starting the engine, and can be connected to and disconnected from the output shaft of the engine. And controlling a power device having a flywheel, and at the time of starting the engine, the motor is controlled to perform cranking, and then the flywheel is connected and controlled to perform cranking to obtain the rotational speed of the flywheel. Flywheel rotation speed acquisition means, and cranking output calculation means for calculating the cranking output of the motor at the time of engine start based on the acquired rotation speed of the flywheel, and based on the calculated cranking output The motor is controlled when the engine is started.

  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 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 the motor 14 to generate electric power, and generating regenerative electric power with the second motor 16 by the rotational force from the driving wheels 34 due to the inertia of the vehicle. 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. The 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 stored hereinafter. This is referred to as an energy flywheel 42. Note that the energy storage flywheel 42 may be connected to and disconnected from the output shaft of the engine by providing a clutch between the storage flywheel 42 and a normal flywheel, and connecting and disconnecting the clutch.

  The energy storage flywheel 42 can be connected to and disconnected from the engine output shaft 40 by a clutch 44. The clutch 44 is engaged when the engine 12 is rotating, and the energy storage flywheel 42 is driven to rotate by the prime mover such as the engine 12 or the inertia of the vehicle, and the rotational energy is stored in this. 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 energy storage flywheel 42 is kept rotating. When the engine 12 is restarted, the energy stored in the energy storage 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 energy storage 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. There is an effect to do. Further, when the energy storage 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 supplied to the first and second motors 14 and 16 via the first and second inverters 46 and 48 to drive them. The electric power generated by the first and second motors 14 and 16 is sent to the battery 50 via the first and second inverters 46 and 48 and stored therein.

  In order to detect the rotational speeds of the engine 12, the first and second motors 14 and 16, and the energy storage 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 energy storage flywheel based on the driver's request and the state of the vehicle.

  The operation of the energy storage 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 energy storage 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 operation of the engine and motor and connection / disconnection of the energy storage flywheel 42.

  At the time of restart, the energy stored in the energy storage flywheel is not always constant. For example, the longer the time since the clutch 44 is released, the lower the rotational speed of the energy storage flywheel 42 and the stored energy. Further, the rotational speed of the energy storage flywheel 42 at the time of releasing the clutch 44 also changes depending on the situation, and as a result, the energy stored at the time of restart also changes. For this reason, the output at the time of cranking the engine for start-up also varies, and there is a problem that a sufficient cranking rotation speed cannot be obtained, or conversely, the engine suddenly blows up. In the power unit 10 of the present embodiment, the engine 12 is cranked and restarted by the energy storage flywheel 42 and the first motor 14. At this time, the output of the first motor 14 is changed corresponding to the energy stored in the energy storage flywheel 42 so that the sum of outputs for cranking does not change greatly.

  FIG. 2 shows the relationship between the energy accumulated in the energy storage flywheel 42 at the time of engine restart and the output of the first motor for cranking. The accumulated energy is obtained based on the rotation speed of the energy storage flywheel 42 detected by the rotation speed sensor 58. The correspondence relationship between the accumulated energy and the output of the first motor is stored in advance in the hybrid ECU 66. Based on this relationship, the hybrid ECU 66 obtains the rotational speed of the energy storage flywheel 42 and is necessary for the first motor 14. The output of is calculated. If the energy storage flywheel 42 is a normal rigid flywheel such as a disk or an annular plate, the moment of inertia does not change, and the stored energy can be uniquely determined with respect to the rotational speed. it can. The output torque of the first motor 14 and the drive time are calculated so as to obtain the calculated output, and the motor ECU 62 is commanded. In order to obtain the required output of the first motor, as shown in FIG. 3, the output torque or drive time is adjusted. As shown by the solid line in FIG. 3, when a larger output is required than when the first motor is driven, the output torque is increased as shown by a broken line, or the time is increased as shown by a one-dot chain line. It is also possible to control both at the same time.

  As described above, by adjusting the cranking output of the first motor 14 in accordance with the amount of energy stored in the energy storage flywheel 42, the sum total of the cranking output is not constant or greatly changed. Can do. As a result, a necessary and sufficient cranking output is obtained, the engine is reliably restarted, and the occurrence of vibrations and shocks is also suppressed.

  In the present embodiment, the power unit that performs cranking by the motor that is used for running and power generation of the engine has been described. Can be restarted.

It is a schematic block diagram of the power plant which concerns on this embodiment. It is a figure which shows the relationship between the stored energy of the energy storage flywheel at the time of engine restart, and the output of a 1st motor. It is a figure which shows control of the 1st motor at the time of engine restart.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Power unit, 12 Engine, 14 1st motor, 16 2nd motor, 18 Power distribution integration mechanism, 40 Engine output shaft, 42 Energy storage flywheel, 58 Rotational speed sensor,

Claims (5)

An engine that drives the vehicle;
A motor used to start the engine;
A flywheel that accumulates energy by rotating and can be connected to and disconnected from the output shaft of the engine;
A rotational speed sensor for detecting the rotational speed of the flywheel;
A control unit for controlling operation of the engine and motor and connection / disconnection of the flywheel;
Have
A power unit that performs cranking by cranking by a motor and energy accumulated in a flywheel at the time of engine start,
The control unit changes the cranking output by the motor according to the detected rotational speed of the flywheel when starting the engine.
A vehicular power plant.   2. The vehicle power device according to claim 1, wherein the control unit changes a cranking output of the motor by changing an output torque of the motor. 3.   3. The power plant according to claim 1, wherein the control unit changes a cranking output of the motor by changing a time during which the motor rotates. 4.   The power unit according to any one of claims 1 to 3, wherein the power unit is a power unit of a hybrid vehicle, and the motor is a motor used for driving or power generation of the vehicle. A vehicular power plant. An engine, a motor used for starting the engine, and a flywheel that accumulates energy by rotating and that can be connected to and disconnected from the output shaft of the engine are controlled. A control device for a vehicle power unit that performs cranking by controlling, and in addition to this, performs connection control of the flywheel to perform cranking,
Flywheel rotation speed acquisition means for acquiring the rotation speed of the flywheel;
Cranking output calculation means for calculating the cranking output of the motor at the time of engine start based on the obtained rotational speed of the flywheel;
And a control device for a vehicle power unit, wherein the motor is controlled at the time of engine start based on the calculated cranking output.

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