JP2021160584A - Controller for hybrid system - Google Patents

Abstract

To provide a controller for hybrid system capable of suppressing tooth hitting sound when engine starts and starting generating power by a motor early according to a power generation request.SOLUTION: When an engine start request (a power generation request of a motor for power generation) is given, power running of a motor for power generation is performed. By the power running of the motor for power generation, torque in a power running direction is outputted from the motor for power generation, and motoring of the engine is performed. By the motoring, a crankshaft of the engine rotates and its rotation frequency increases. When the torque in the power running direction outputted by the motor for power generation increases up to a certain level, the certain torque is held. When the engine rotation frequency is beyond a prescribed value, the torque in the power running direction outputted by the motor for power generation is lowered (T1). Then, before the torque in the power running direction outputted by the motor for power generation lowers to 0, the engine is ignited (T2).SELECTED DRAWING: Figure 2

Description

The present invention relates to a control device for a hybrid system.

Conventionally, a vehicle using a hybrid system as a drive system, a so-called hybrid vehicle (HV), is known.

The series hybrid vehicle is equipped with an engine, a power generation motor that generates power from the engine, a drive motor that generates power for driving, and a battery. When the output (required output) required of the drive motor by the user is small, the drive motor is driven by the power from the battery, and the hybrid vehicle runs on the EV (Electric Vehicle) with the power output from the drive motor. When the required output increases, the power generation motor is required to generate power, the engine is started, the drive motor is driven by the power generated by the power generation motor by the power of the engine and the power from the battery, and the power output from the drive motor. The hybrid vehicle runs on HV.

When the engine is started, power from the battery is supplied to the power generation motor, the power generation motor is driven, and the engine is motorized by the power generation motor. When the crankshaft of the engine rotates (cranking) due to motoring and the number of revolutions rises to the number of revolutions required for starting, the spark plug of the engine is sparked and the engine is started.

An engine output gear is provided on the crankshaft of the engine, a power generation motor gear is provided on the rotating shaft of the power generation motor, and the engine output gear and the power generation motor gear mesh with each other to transmit power between the engine and the power generation motor. It has become so. Therefore, when the engine is started, the teeth of the engine output gear and the teeth of the power generation motor gear may strongly collide with each other, and a so-called rattling noise may be generated. In order to suppress the generation of this rattling noise, for example, after increasing the rotation speed of the power generation motor to a predetermined value or more, the torque direction of the power generation motor is reversed from the power running direction to the regenerative direction, and the torque in the regenerative direction is the engine. A technique has been proposed in which the engine is ignited after the friction torque exceeds the above.

JP-A-2018-17212

However, with this technology, it takes time to ignite the engine, and the time lag from the request for power generation to the start of power generation becomes large. In a vehicle with a smaller battery capacity than other vehicles, it is necessary to start power generation early from the power generation request in order to exhibit the same acceleration performance as other vehicles.

An object of the present invention is to provide a control device for a hybrid system capable of suppressing the generation of rattling noise at the time of starting an engine and starting power generation by a motor at an early stage from a power generation request.

In order to achieve the above object, the control device of the hybrid system according to one aspect of the present invention is mounted on a vehicle, and a tooth and a tooth groove are provided between the rotation shaft of the engine and the rotation shaft of the motor for power generation. It is a control device that controls a hybrid system in which a meshing means that transmits power by meshing is intervened. It includes an ignition means for reducing the torque in the power running direction output by the motor and igniting the engine before the torque in the power running direction becomes zero.

According to this configuration, the torque in the power running direction output from the motor is reduced during engine cranking and before the engine is ignited. Then, the engine is ignited before the torque in the power running direction becomes zero. As a result, the engine is ignited in a state where the teeth of the motor gear provided on the rotating shaft of the motor are in contact with the teeth of the engine gear provided on the rotating shaft of the engine from the upstream side in the rotational direction, and after the ignition. As the engine speed increases, the teeth of the engine gear come into contact with the teeth of the motor gear from the upstream side in the rotation direction. That is, within the period from the start of engine cranking to the start of power generation by the motor after the initial and complete explosion of the engine, the magnitude relationship between the engine torque and the torque in the power running direction of the motor due to fluctuations in engine torque. By keeping the torque in the power running direction of the motor in an appropriate range larger than 0 in the region where there is a possibility of replacement, it is possible to prevent the replacement of the magnitude relationship. As a result, the teeth of the motor gear are suppressed from floating from the teeth of the engine gear even during the compression process in which the fluctuation of the torque of the engine becomes a valley, so that the teeth of the engine gear come into contact with the teeth of the motor gear, resulting in a rattling noise. Can be suppressed. Moreover, since the engine is ignited before the rotation direction of the torque output from the motor is reversed in the regeneration direction, it is possible to start power generation by the motor earlier than the conventional technique.

The control device of the hybrid system according to another aspect of the present invention is mounted on a vehicle, and is engaged to transmit power by meshing teeth and tooth grooves between the rotating shaft of an engine and the rotating shaft of a motor for power generation. A control device that controls a hybrid system with means intervening, and a cranking means that cranks the engine by the torque in the power running direction output by the motor, and a power running that the motor outputs during cranking of the engine. It includes an ignition means for igniting the engine without reducing the torque in the direction.

According to this configuration, during engine cranking, the engine is ignited without reducing the torque in the power running direction output from the motor. As a result, the engine is ignited in a state where the teeth of the motor gear provided on the rotating shaft of the motor are in contact with the teeth of the engine gear provided on the rotating shaft of the engine from the upstream side in the rotational direction, and after the ignition. As the engine speed increases, the teeth of the engine gear come into contact with the teeth of the motor gear from the upstream side in the rotation direction. At this time, the engine gear and the motor gear are rotating in the same direction, and the difference in rotation speed between them is small. Therefore, it is possible to suppress the generation of rattling noise when the teeth of the engine gear come into contact with the teeth of the motor gear. Moreover, since the engine is ignited without lowering the torque in the regeneration direction output from the motor, it is possible to start power generation by the motor earlier than the conventional technique.

According to the present invention, it is possible to suppress the generation of rattling noise when the engine is started, and it is possible to start power generation at an early stage from the power generation request.

It is a block diagram which shows the structure of the electric vehicle which mounts the control device which concerns on one Embodiment of this invention. It is a figure which shows the time change of the output torque (MG1 torque) of a power generation motor at the time of starting an engine. It is a figure which shows the time change of MG1 torque which concerns on 2nd Embodiment. It is a figure which shows the time change of MG1 torque which concerns on 3rd Embodiment. It is a figure which shows the time change of MG1 torque which concerns on 4th Embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Hybrid system configuration>
FIG. 1 is a block diagram showing a configuration of an electric vehicle 1 according to an embodiment of the present invention.

The electric vehicle 1 employs a series-type hybrid system, and is equipped with an engine (E / G) 2, a power generation motor (MG1) 3, and a drive motor (MG2) 4.

The engine 2 is, for example, a 3-cylinder 4-stroke gasoline engine, an electronic throttle valve for adjusting the amount of intake air into the combustion chamber of the engine 2, an injector (fuel injection device) for injecting fuel into the intake air, and a combustion chamber. It is equipped with an ignition plug that causes an electric discharge. The rotating shaft (crankshaft) of the engine 2 is connected to the engine gear 6 via a damper 5 that reduces torsional vibration and bending vibration of the rotating shaft.

The power generation motor 3 includes, for example, a permanent magnet synchronous motor. The rotating shaft of the power generation motor 3 is provided so that the motor gear 7 rotates integrally. The motor gear 7 meshes with the engine gear 6.

The drive motor 4 is composed of, for example, a permanent magnet synchronous motor larger than the power generation motor 3. The rotating shaft of the drive motor 4 is connected to a power transmission mechanism. The power transmission mechanism includes a differential gear, and the power of the drive motor 4 is transmitted to the differential gear and distributed from the differential gear to the left and right drive wheels (front wheels or rear wheels) 8.

Further, the electric vehicle 1 is equipped with a PCU (Power Control Unit) 11 and a battery (BAT) 12.

The PCU 11 is a unit for controlling the drive of the power generation motor 3 and the drive motor 4, and includes an MG1 inverter (INV1) 13, an MG2 inverter (INV2) 14, and a boost converter (BstCONV) 15. The MG1 inverter 13 and the MG2 inverter 14 are provided with two IGBT (Insulated Gate Bipolar Transistors) series circuits corresponding to the U-phase, V-phase, and W-phase, and are connected in series. It has a circuit configuration in which circuits are connected in parallel with each other.

The battery 12 is an assembled battery in which a plurality of secondary batteries are combined, and outputs, for example, DC power of about 200 to 350 V (volts).

When the electric vehicle 1 is accelerating, the drive motor 4 is power-running, and the drive motor 4 generates power for power-running. At this time, the DC power output from the battery 12 is boosted by the boost converter 15, the boosted DC power is converted into three-phase AC power by the MG2 inverter 14, and the three-phase AC power is converted to the drive motor 4. Be supplied. This consumes the power of the battery 12.

Further, when the engine 2 is started, the DC power output from the battery 12 is boosted by the boost converter 15, the boosted DC power is converted into three-phase AC power by the MG1 inverter 13, and the three-phase AC power is generated. It is supplied to the motor 3. As a result, the power generation motor 3 is power-driven, and the engine 2 is motorized by the power generation motor 3. By this motoring, the crankshaft of the engine 2 rotates (cranking), and when the rotation speed rises to the rotation speed required for starting, the spark plug of the engine 2 is sparked and the engine 2 is started.

When the power generation motor 3 is operated for power generation while the engine 2 is operating, the power generation motor 3 generates three-phase AC power. The three-phase AC power generated by the power generation motor 3 is converted into DC power by the MG1 inverter 13. Then, the DC power output from the MG1 inverter 13 is converted into three-phase AC power by the MG2 inverter 14, and the three-phase AC power is supplied to the drive motor 4. When it is not necessary to supply electric power to the drive motor 4, the DC power output from the MG1 inverter 13 is stepped down by the boost converter 15, and the DC power after stepping down is supplied to the battery 12. The battery 12 is charged.

When the electric vehicle 1 decelerates, the drive motor 4 is regeneratively operated, and the power transmitted from the drive wheels 8 to the drive motor 4 is converted into three-phase AC power. At this time, the drive motor 4 becomes a resistance of the traveling drive system, and the resistance acts as a braking force (regenerative braking force) for braking the electric vehicle 1. The three-phase AC power generated by the drive motor 4 is converted into DC power by the MG2 inverter 14. Then, the DC power output from the MG2 inverter 14 is stepped down by the boost converter 15, and the DC power after the step-down is supplied to the battery 12, so that the battery 12 is charged.

<Control system>
The electric vehicle 1 is provided with an ECU (Electronic Control Unit) having a configuration including a microcomputer. Although FIG. 1 shows only one ECU 16 for controlling the PCU 11, the electric vehicle 1 is equipped with a plurality of ECUs for controlling each part. A plurality of ECUs including the ECU 16 are connected so as to be capable of bidirectional communication by a CAN (Controller Area Network) communication protocol. Further, various sensors necessary for control are connected to the ECU 16.

<Engine start control 1>
FIG. 2 is a diagram showing a time change of the output torque (MG1 torque) of the power generation motor 3 when the engine 2 is started.

When a start request for the engine 2 (a power generation request for the power generation motor 3) is generated, the PCU 11 is controlled by the ECU 16 to power-operate the power generation motor 3. By the power running operation of the power generation motor 3, torque in the power running direction is output from the power generation motor 3, and the engine 2 is motorized. By this motoring, the crankshaft of the engine 2 rotates (cranking), and the rotation speed (engine rotation speed) increases.

When the torque in the power running direction output from the power generation motor 3 rises to a certain level, the constant torque is maintained. When the engine speed exceeds a predetermined value, the torque in the power running direction output from the power generation motor 3 is reduced (time T1).
After that, the engine 2 is ignited (time T2) before the torque in the power running direction output from the power generation motor 3 drops to zero.

<Effect>
As described above, during the cranking of the engine 2, the torque in the power running direction output from the power generation motor 3 is reduced before the ignition of the engine 2. Then, the engine 2 is ignited before the torque in the power running direction becomes zero. As a result, the engine 2 is in a state where the teeth of the motor gear 7 provided on the rotating shaft of the power generation motor 3 are in contact with the teeth of the engine gear 6 provided on the rotating shaft of the engine 2 from the upstream side in the rotational direction. Is ignited, and when the rotation speed of the engine 2 increases after the ignition, the teeth of the engine gear 6 come into contact with the teeth of the motor gear 7 from the upstream side in the rotation direction. That is, within the period from the start of cranking of the engine 2 to the start of power generation by the power generation motor 3 after the initial and complete explosions of the engine 2, the torque of the engine 2 and the power generation motor are caused by fluctuations in the torque of the engine 2. In a region where the magnitude relationship with the torque in the force running direction of 3 may be exchanged, the torque in the force traveling direction of the power generation motor 3 is maintained in an appropriate range larger than 0 to prevent the change in the magnitude relationship. can. As a result, the teeth of the motor gear 7 are prevented from floating from the teeth of the engine gear 6 even during the compression process in which the fluctuation of the torque of the engine 2 becomes a valley, so that the teeth of the engine gear 6 come into contact with the teeth of the motor gear 7. It is possible to suppress the generation of beating noise due to this. Moreover, since the engine 2 is ignited before the rotation direction of the torque output from the power generation motor 3 is reversed in the regeneration direction, the power generation request (starting request to the engine 2) is earlier than that of the conventional technique. The power generation by the power generation motor 3 can be started.

<Engine start control 2>
FIG. 3 is a diagram showing a time change of MG1 torque according to the second embodiment.
When starting the engine 2, the torque control described below may be performed instead of the torque control of the power generation motor 3 described above.

That is, when the torque in the power running direction output from the power generation motor 3 rises to a certain level during cranking of the engine 2, the constant torque is maintained. When the engine speed exceeds a predetermined value, the torque in the power running direction output from the power generation motor 3 is reduced (time T11).

After that, before the torque in the power running direction output from the power generation motor 3 drops to 0, the torque in the power running direction output from the power generation motor 3 is momentarily increased (time T12), and the torque peaks. The engine 2 is ignited at the timing of (time T3).

<Effect>
Even with such torque control, it is possible to obtain the same effect as in the case where the torque control described with reference to FIG. 2 is performed.
<Engine start control 3>
FIG. 4 is a diagram showing a time change of MG1 torque according to the third embodiment.
When the engine 2 is started, the torque control described below may be performed.

That is, when the torque in the power running direction output from the power generation motor 3 rises to a certain level during cranking of the engine 2, the constant torque is maintained. Then, even if the engine speed exceeds a predetermined value, the engine 2 is ignited without reducing the torque in the power running direction output from the power generation motor 3 (time T21).
<Effect>

During the cranking of the engine 2, the engine 2 is ignited without reducing the torque in the power running direction output from the power generation motor 3. As a result, the engine 2 is in a state where the teeth of the motor gear 7 provided on the rotating shaft of the power generation motor 3 are in contact with the teeth of the engine gear 6 provided on the rotating shaft of the engine 2 from the upstream side in the rotational direction. Is ignited, and when the rotation speed of the engine 2 increases after the ignition, the teeth of the engine gear 6 come into contact with the teeth of the motor gear 7 from the upstream side in the rotation direction. At this time, the engine gear 6 and the motor gear 7 are rotating in the same direction, and the difference in rotation speed between them is small. Therefore, it is possible to suppress the generation of rattling noise when the teeth of the engine gear 6 come into contact with the teeth of the motor gear 7. Moreover, since the engine 2 is ignited without lowering the torque in the regeneration direction output from the power generation motor 3, the power generation motor is earlier than the conventional technology from the power generation request (starting request to the engine 2). The power generation by 3 can be started.

<Engine start control 4>
FIG. 5 is a diagram showing a time change of MG1 torque according to the fourth embodiment.
When the engine 2 is started, the torque control described below may be performed.

That is, when the torque in the power running direction output from the power generation motor 3 rises to a certain level during cranking of the engine 2, the constant torque is maintained. When the engine speed exceeds a predetermined value, the torque in the power running direction output from the power generation motor 3 is increased (time T31). After that, when the engine 2 is ignited (time T32), the torque in the power running direction output from the power generation motor 3 is reduced.

<Effect>
Even with such torque control, it is possible to obtain the same effect as in the case where the torque control described with reference to FIG. 4 is performed.

<Modification example>
Although one embodiment of the present invention has been described above, the present invention can also be implemented in other embodiments.

For example, in the above-described embodiment, the electric vehicle 1 equipped with the series system hybrid system 2 is taken up, but the present invention can be applied to a hybrid system of a system other than the series system such as a series parallel system. In a series-parallel hybrid system, for example, the engine and motor are connected to a planetary gear mechanism, and the power from the engine can be split and distributed to the motor and drive wheels, and the power from the engine and from the motor. Power can be combined and transmitted to the drive wheels.

In addition, various design changes can be made to the above-mentioned configuration within the scope of the matters described in the claims.

1: Electric vehicle (vehicle)
2: Engine 3: Power generation motor (motor)
16: ECU (control device, cranking means, ignition means)

Claims (2)

A control device mounted on a vehicle to control a hybrid system in which a meshing means for transmitting power by meshing teeth and tooth grooves is interposed between the rotating shaft of an engine and the rotating shaft of a motor for power generation. And
A cranking means for cranking the engine by the torque in the power running direction output by the motor, and
A control device including an ignition means that reduces the torque in the power running direction output by the motor during cranking of the engine and ignites the engine before the torque in the power running direction becomes zero. A control device mounted on a vehicle to control a hybrid system in which a meshing means for transmitting power by meshing teeth and tooth grooves is interposed between the rotating shaft of an engine and the rotating shaft of a motor for power generation. And
A cranking means for cranking the engine by the torque in the power running direction output by the motor, and
A control device including an ignition means for igniting the engine without reducing the torque in the power running direction output by the motor during cranking of the engine.

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