JP4702181B2 - VEHICLE POWER DEVICE AND CONTROL DEVICE THEREOF - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a burden on a clutch for connecting/disconnecting a flywheel to/from an output shaft of an engine, in a vehicular power device restarting the engine by rotational energy stored in the flywheel. <P>SOLUTION: When starting the engine 12, first of all, the rotational speed of the engine 12 is increased by output of a first motor 14. When the rotational speed reaches a predetermined speed, engagement of the clutch 44 is started, and the rotational speed of the engine 12 is increased by the energy storage flywheel 42. When reaching the predetermined speed, fuel is supplied to the engine 12, and the engine is started by igniting. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

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 technique described in the above-mentioned patent document, there is no suggestion at what timing the energy stored in the rotating flywheel and the output of the motor are used when the engine is restarted. If cranking is performed by connecting a flywheel that rotates at high speed from a state where the engine is stopped, the difference between the rotational speed of the flywheel and the engine is large, and the burden of the clutch that connects the flywheel to the engine output shaft is increased. growing. Further, vibration and shock occur when the clutch is connected.

  An object of the present invention is to reduce the burden on a clutch connected to an engine output shaft and suppress the occurrence of vibration and shock when the engine is restarted using energy stored in a flywheel.

In order to solve the above-described problems, a vehicle power device according to the present invention includes an engine that drives a vehicle, a motor that is used to start the engine, a flywheel that accumulates energy by rotating, and a flywheel. A clutch that connects / disconnects to / from the engine output shaft, a control unit that controls engine / motor operation and clutch connection / disconnection operation, an engine rotational speed sensor that detects engine rotational speed, and a flywheel rotational speed A flywheel rotational speed sensor that detects the engine, and performs cranking by the motor and cranking by the energy accumulated in the flywheel when starting the engine. performs cranking, the engine rotational speed detected reaches a predetermined speed, and test When to fly below the wheel rotation speed, characterized by adding the cranking by the flywheel and the clutch is engaged.

  Further, a flywheel rotational speed sensor for detecting the rotational speed of the flywheel can be provided, and the control unit controls the engagement pressure of the clutch based on the difference between the detected flywheel rotational speed and the engine rotational speed. You can do that.

Furthermore, when the cranking by a flywheel is started, the said control part can be controlled to reduce the cranking torque by a motor.

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

A control device for a vehicle power unit according to another aspect of the present invention includes an engine that drives a vehicle, a motor that is used to start the engine, a flywheel that accumulates energy by rotating, and a flywheel. An engine rotation that controls a power unit having a clutch that is connected to and disconnected from an engine output shaft, performs cranking by using a motor and a flywheel at the time of engine start, and further acquires an engine rotation speed connecting a speed obtaining means, a flywheel rotational speed acquisition means for detecting a rotational speed of the flywheel, when the engine rotational speed acquired is reached to a predetermined value, and the detected fly lower wheel rotation speed, the clutch Clutch control means for controlling.

  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. The energy storage flywheel 42 may be configured so as to be connected to and disconnected from the engine output shaft 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 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 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 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. Accordingly, 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 energy storage flywheel 42.

  At the time of restart, if the storage energy flywheel 42 rotating at high speed is directly connected to the stopped engine 12, the difference in rotational speed between the engine 12 and the storage energy flywheel 42 is large, and the burden on the clutch 44 is large. Become. Further, vibration and shock occur when the clutch 44 is connected. In the power unit 10 of the present embodiment, in order to reduce vibrations and shocks caused by the connection of the clutch 44 at the time of restart, the engine is first cranked by the first motor 14, and when a predetermined rotational speed is reached, The clutch 44 is connected and cranking is performed by the energy storage flywheel. This control will be described in detail below.

  FIG. 2 shows the rotational speed 100 of the energy storage flywheel 42, the engine rotation speed 102, the transmission rate 104 of the clutch 44, the torque that drives the engine 12 of the first motor 14 and the energy storage flywheel 42 when the engine is restarted. A time chart showing the relationship is shown. A trapezoidal line 106 of the chart indicating torque indicates the torque generated by the first motor 14, and a portion 108 surrounded by the trapezoid of the line 106 becomes energy given to the engine 12 by the first motor 14. Further, a line 110 of the chart indicating the torque indicates the torque generated by the energy storage flywheel 42, and a portion 112 surrounded by the line 110 and the line 106 becomes energy given to the engine 12 by the energy storage flywheel 42.

  When the hybrid ECU 66 determines that the engine 12 needs to be restarted, the rotational speed of the energy storage flywheel 42 detected by the rotational speed sensor 58 is read, and control according to the rotational speed is performed. . First, a command for rotationally driving the first motor 14 to perform cranking of the engine is given, and the motor ECU 62 controls the first and second motors 14 and 16 based on this command. The first motor 14 is controlled so as to gradually increase the output torque, so that the rotation speed of the engine 12 rapidly increases and vibrations and the like are not generated.

  At the time t1 when the rotational speed 103 of the engine 12 reaches a predetermined rotational speed Net, the engagement of the clutch 44 is started. The rotational speed of the engine is detected by a rotational speed sensor 52. The transmission rate of the clutch 44 is a ratio of the input / output rotational speeds. If it is 0 percent, it represents the state when the clutch is completely disengaged, and 100 percent represents that the clutch is completely engaged. The transmission rate of the clutch is gradually increased, and the energy stored in the energy storage flywheel 42 is gradually transmitted to the engine 40. As a result, the engine speed further increases, and at a predetermined time, the driving of the first motor 14 is finished, and the engine speed is increased by driving the energy storage flywheel 42. The time point when the driving of the first motor 14 is finished can be changed according to the energy stored in the energy storage flywheel 42 first. If the stored energy is large, the first motor 14 is stopped in a short time. Conversely, if the stored energy is small, the driving by the first motor 14 can be continued for a long time. When the engine speed reaches a predetermined value, fuel is supplied, ignition is performed, and the engine is started.

  As described above, first, the first motor 14 increases the rotational speed of the engine 12, and after reaching a predetermined rotational speed, the clutch 44 is connected to increase the rotational speed of the engine by the energy storage flywheel 42. Thereby, the burden of the clutch 44 can be reduced. In addition, vibrations, shocks, and the like due to sudden speed changes can be reduced.

  In the present embodiment, the power device that cranks the engine by a motor used for running and power generation has been described. However, a motor dedicated to starting, a motor that performs power generation but is not used for running, and an energy storage flywheel It is also possible to perform restart by combining these.

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 the energy storage flywheel at the time of engine restart, the rotational speed of an engine, the transmission rate of a clutch, and a starting torque.

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 Storage energy flywheel, 44 Clutch, 52 Engine rotational speed sensor, 58 Storage energy flywheel 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
A clutch that connects / disconnects the flywheel to / from the engine output shaft;
A control unit for controlling operation of the engine and motor and connection / disconnection of the clutch;
An engine speed sensor for detecting the engine speed;
A flywheel rotational speed sensor for detecting the rotational speed of the flywheel;
A vehicle power device that performs cranking by a motor and cranking by energy accumulated in a flywheel when the engine is started,
When the engine is started, the control unit first performs cranking by a motor. When the detected engine rotation speed reaches a predetermined speed and is lower than the detected flywheel rotation speed , a clutch is connected to the flywheel. Add cranking,
A vehicular power plant. The vehicle power device according to claim 1 ,
The said control part is a vehicle power device which controls the engagement pressure of a clutch based on the difference of the detected flywheel rotational speed and engine rotational speed. 3. The vehicle power device according to claim 1, wherein the control unit reduces the cranking torque by the motor when cranking by the flywheel is started. 4.   It is a vehicle power device described in any one of Claims 1-3, Comprising: The said power device is a power device of a hybrid vehicle, The said motor is a motor utilized for the drive of the said vehicle. A vehicle power device characterized by the above. Controls a power unit having an engine that drives a vehicle, a motor that is used to start the engine, a flywheel that stores energy by rotating, and a clutch that connects / disconnects the flywheel to / from the engine output shaft. And, at the time of engine start, a control device for a vehicle power unit that performs cranking using a motor and a flywheel,
Engine speed acquisition means for acquiring the engine speed;
Flywheel rotation speed acquisition means for detecting the rotation speed of the flywheel;
When the acquired engine rotational speed is reached to a predetermined value, and the detected fly lower wheel rotation speed, a clutch control means for connecting controls the clutch,
A control device for a vehicle power unit having

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