JP2006132391A - Control device of series type hybrid vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device of a series type hybrid vehicle, in which the power generation amount of a generator can be controlled constant at the time of engine working. <P>SOLUTION: The control device of the series type hybrid vehicle is comprised of the generator (16), an internal combustion engine (18) to drive the generator, a battery (4) charged by the output of the generator for running, a motor (6) supplied by electric power from the battery and to drive a wheel for running, a hybrid control means (22) to control the generator and the motor, and an engine control means (24) to control the internal combustion engine. When driving the generator based on an accelerator opening (26), the hybrid control means outputs a required rotational speed for keeping the rotational speed of the internal combustion engine constant to the engine control means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a control device for a series hybrid vehicle that uses an internal combustion engine dedicated to power generation and drives wheels with a motor.

A series type hybrid vehicle is equipped with an electric motor (motor) as a driving force source of the vehicle. The motor is supplied with power from a battery, and the battery is charged by the output of the generator. The generator is driven by a relatively small internal combustion engine (engine).
This type of vehicle is controlled by an electronic controller. Specifically, the vehicle is provided with a hybrid ECU that controls the generator and the motor, and an engine ECU that controls the engine. A signal for detecting the driving state of the vehicle is provided between these ECUs. Each management control is performed based on this. For example, when the engine is driven, the hybrid ECU calculates a required engine output from the accelerator sensor signal and outputs the calculated engine output to the engine ECU. The engine ECU controls the fuel injection amount to satisfy the required engine output (see, for example, Patent Document 1).
JP 2002-285823 A

By the way, the engine ECU uses a map composed of the engine speed and load, reads the fuel injection amount satisfying the required engine output from this map, adjusts the fuel injection amount, and drives the engine. .
However, in the series type hybrid vehicle, if engine control is performed to satisfy the required engine output as in the conventional case, if the environmental conditions such as the atmospheric temperature or the warm-up conditions of the engine or the generator change, the engine or generator Both the rotational speed of the generator and the load change, and the output fluctuation range becomes wide. As a result, the rotational speed of the generator fluctuates greatly, and the fluctuation range of the power generation amount also increases, and there is a concern that the battery may be overcharged or insufficiently charged to adversely affect the driving of the wheels by the motor.

In addition, when the output fluctuation range becomes wide and there are a plurality of operating points with the same output, the convergence of the control is poor, and there is a problem that the reliability of the engine control and the generator control is lacking.
The present invention has been made in view of such a problem, and an object of the present invention is to provide a control device for a series-type hybrid vehicle that can control the power generation amount of a generator to be constant when the engine is operating.

  In order to achieve the above object, a control device for a series hybrid vehicle according to claim 1 includes a generator, an internal combustion engine that drives the generator, a battery for traveling charged by the output of the generator, and a battery A driving motor for driving the wheels, a hybrid control means for controlling the generator and the motor, and an engine control means for controlling the internal combustion engine. When the generator is driven based on the above, a required rotational speed for making the rotational speed of the internal combustion engine constant is output to the engine control means.

  In the invention according to claim 2, the hybrid control means outputs the rotational speed for achieving the premixed combustion to the engine control means as the required rotational speed, and the engine control means performs the premixed combustion control based on the required rotational speed. It is characterized by performing.

  Therefore, according to the control apparatus for a series hybrid vehicle of the first aspect of the present invention, when the hybrid control means drives the generator in accordance with the accelerator opening, the engine speed is kept constant. Is calculated and output to the engine control means. The engine control means reads the fuel injection amount for maintaining the required engine speed, that is, engine control that satisfies the required speed, The injection amount is adjusted. Therefore, a constant engine speed is always maintained during operation of the engine, regardless of environmental conditions such as atmospheric temperature and changes in warm-up conditions of the internal combustion engine and the generator. As a result, the rotational speed of the generator is kept constant, the fluctuation range of the power generation amount becomes very small, and the battery is not overcharged or insufficiently charged.

Further, when a constant engine rotation speed is always maintained, the fluctuation range of the output of the engine or the generator is reduced, and the operation point having the same output can be uniquely determined. Therefore, the convergence of control is improved, and the reliability of engine control and generator control is improved.
Furthermore, according to the second aspect of the present invention, since the operating point with the same output can be uniquely determined, even the premixed combustion with a narrow combustion establishment window can be easily executed. And if establishment of this premix combustion becomes easy, deployment to a vehicle will become easy.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a series hybrid vehicle. As the vehicle, for example, a large vehicle such as a shared bus that frequently uses low-speed traveling in an urban area is assumed, and the control device according to an embodiment of the present invention is applied.
As shown in the figure, a traveling motor (motor) 2 is mounted as a driving force source in the vehicle, and a rotating shaft of the traveling motor 2 is connected via a speed reducer 8 and a differential device 10. A pair of drive wheels 12 and 14 are connected.

  The travel motor 2 is electrically connected to a travel battery (battery) 4 via an inverter 6, and the travel battery 4 supplies power to the travel motor 2. The travel motor 2 also functions as an energy regenerative brake, that is, a generator using braking energy when the vehicle is braked. Specifically, when the driver of the vehicle operates a brake (not shown), the traveling motor 2 simultaneously generates power while generating a braking force, and this generated power is charged in the traveling battery 4.

The inverter 6 is also electrically connected to a generator (generator) 16 and an auxiliary motor (not shown) for driving an auxiliary device such as an air brake air compressor.
The rotating shaft of the generator 16 is connected to the output shaft of a power generation engine (internal combustion engine) 18. That is, the generator 16 is driven by an engine 18 dedicated to power generation, and generates power by being rotated synchronously via a crankshaft (not shown) of the engine 18. The electric power generated by the generator 16 is stored in the traveling battery 4 via the inverter 6. The generator 16 also has a function of rotating by being supplied with electric power when the power generation engine 18 is stopped, and starting the power generation engine 18 via the crankshaft. The power generation engine 18 may be started with a starter.

  Further, the inverter 6 adjusts the voltage and current from the traveling battery 4 or the voltage and current generated by the generator 16 or the traveling motor 2 as described above, and the auxiliary motor, the traveling motor 2 or the traveling motor is adjusted. Stable power is supplied to the battery 4. A relay / fuse 20 is interposed between the inverter 6 and the traveling battery 4. This relay fuse 20 is electrically connected to the inverter 6, receives information from the inverter 6, permits energization from the traveling battery 4 to the traveling motor 2, or travels from the traveling battery 4. It has a function of preventing an excessive current from flowing through the motor 2 or preventing the generator 16 and the traveling motor 2 during regenerative braking from being overcharged by the traveling battery 4.

Further, the inverter 6 is connected to a hybrid ECU (hybrid control means) 22 so as to be able to communicate with each other. As shown in the figure, the inverter 6 is also connected to the traveling motor 2 and the generator 16 so that they can communicate with each other.
A driver's output request is captured on the input side of the hybrid ECU 22. That is, an accelerator sensor 28 that detects the operation amount of the accelerator pedal 26, a vehicle speed sensor (not shown) that detects the vehicle speed, a battery management device 30, and the like are connected. The battery management device 30 manages the battery state of the traveling battery 4, and outputs information such as the storage amount to the hybrid ECU 22. The hybrid ECU 22 controls the generator 16 and the traveling motor 2 via the inverter 6.

  Further, as will be described later, the hybrid ECU 22 of the present embodiment operates the power generation engine 18 when the generator 16 is driven based on the operation amount of the accelerator pedal 26 to charge the traveling battery 4. A required rotational speed Ne for making the rotational speed of the power generation engine 18 constant is output to an engine ECU (engine control means) 24. This is for controlling the rotational speed of the generator 16 to be a constant rotational speed.

  The engine ECU 24 keeps the rotational speed constant according to the required rotational speed Ne, and controls diesel combustion and premixed compression ignition combustion (HCCI combustion) according to the operating state of the vehicle. Specifically, in the diesel combustion of the present embodiment, the fuel injection timing is set in the vicinity of the compression top dead center (a range of about 20 ° BTDC to 5 ° ATDC). On the other hand, in HCCI combustion, the angle is advanced to about 120 ° BTDC.

In addition, each management control is performed between these ECU22,24 based on the signal which detects the driving | running state of a vehicle.
In the hybrid vehicle configured as described above, when the vehicle travels, a required motor torque signal corresponding to the operation amount of the accelerator pedal 26 is output from the hybrid ECU 22 to the inverter 6, and the voltage and current from the travel battery 4 are adjusted. The As a result, the traveling motor 2 generates a desired motor torque. Here, in the present embodiment, the charged amount of the traveling battery 4 is secured by the power generation of the generator 16 based on the operation amount of the accelerator pedal 26 (required accelerator opening control).

Further, in the hybrid vehicle, as a general action, an auxiliary motor such as an air compressor is driven when the vehicle is traveling, so that the auxiliary motor is appropriately driven by electric power from the traveling battery 4.
On the other hand, when the vehicle is in a braking state and the operation amount of the accelerator pedal 26 is zero, regenerative braking is performed by the traveling motor 2. In this case, electric power is generated by the traveling motor 2 and the traveling battery 4 is charged.

  Further, for example, when a decrease in the charge level (SOC) of the traveling battery 4 is detected, the power generation engine 18 is started by a signal from the engine ECU 24. Then, the power generation engine 18 operates the generator 16 to generate power, and charges the traveling battery 4 according to the SOC. When the SOC of the traveling battery 4 is low, power corresponding to the power consumption of the traveling motor 2 is directly supplied from the generator 16 to the traveling motor 2, and the power generation surplus of the generator 16 is the traveling battery 4. Is charged.

FIG. 2 is a timing chart of engine start control and required accelerator opening control of the generator 16 in the control device of the present embodiment. Hereinafter, the operation of the control device configured as described above will be described.
When the power generation engine 18 is stopped, engine start control, specifically, the generator 16 is first driven. That is, when a signal for releasing the stop of the power generation engine 18 is input to the hybrid ECU 22, the generator 16 starts the power generation engine 18. That is, the generator 16 is used as a motor. At this time, the load of the generator 16 is temporarily shifted from the no-load state to the load state in which the traveling battery 4 is discharged, and the power generation engine 18 is driven until the rotation speed reaches the idle rotation.

  After the rotational speed of the power generation engine 18 reaches the idle speed, the hybrid ECU 22 outputs the required rotational speed and the required fuel injection amount to the engine ECU 24 so as to be constant at the idle speed. Thereby, idle rotation is maintained and the load of the generator 16 shifts to a no-load state. As described above, the rotation speed that can be charged is not immediately reached after the engine is stopped, but the rotation speed is first maintained by idle rotation, thereby eliminating disturbance to the power generation engine 18 and stabilizing the control.

  Next, when the engine start control is shifted to the required accelerator opening control, that is, the power generation control based on the operation amount of the accelerator pedal 26 by the generator 16, the hybrid ECU 22 sets the rotational speed of the power generation engine 18 to the power generation rotation. The required rotational speed and the required fuel injection amount are further output to the engine ECU 24. Then, the engine ECU 24 causes the power generation engine 18 to inject fuel and raises the rotation speed to the power generation rotation by PID control. Note that it is possible to use a rotation increase or injection amount restriction (boost pressure map or the like) due to the governor characteristics.

  Subsequently, in the required accelerator opening degree control, the generator 16 is driven using the driving force of the power generation engine 18 to generate power. That is, the hybrid ECU 22 further outputs the required fuel injection amount to the engine ECU 24, and the traveling battery 4 is charged as the load of the power generation engine 18 increases. At this time, the required rotational speed Ne is instructed from the hybrid ECU 22 to the engine ECU 24. More specifically, when the rotational speed of the power generation engine 18 reaches the power generation rotation, the hybrid ECU 22 requires a required rotational speed for maintaining the rotational speed of the power generation engine 18 constant at the power generation rotation. Ne is output to the engine ECU 24. Thereby, the rotational speed of the generator 16 is also maintained constant.

When the load of the generator 16 reaches a power generation load state that becomes a power generation point, the hybrid ECU 22 causes the engine ECU 24 to keep the power generation load constant in addition to the power generation rotation. As a result, the power generation amount of the generator 16 remains constant, and the traveling battery 4 is stably charged.
Next, although not shown, when the hybrid ECU 22 instructs the engine ECU 24 to stop the power generation engine 18 and shifts from the required accelerator opening degree control to the engine stop control, first, the rotation of the power generation engine 18 is performed. The speed is once lowered from the power generation rotation to the idle rotation, and this idle rotation is kept constant. Then, after this idling operation has passed for a predetermined time, the power generation engine 18 is stopped after the intake throttle is throttled. In this way, the engine is not immediately stopped from the power generation rotation but is maintained at the idle rotation, thereby preventing vibration when the engine is stopped.

As described above, the present embodiment focuses on controlling the power generation amount of the generator 16 of the series hybrid vehicle to be constant.
According to the present embodiment, when the generator 16 generates electric power based on the operation amount of the accelerator pedal 26 and charges the traveling battery 4, the hybrid ECU 22 is required to make the engine rotation speed constant. The rotational speed Ne is calculated and output to the engine ECU 24. Therefore, the engine ECU 24 controls the power generation engine 18 that satisfies the required rotational speed Ne, that is, reads the fuel injection amount for always maintaining a constant engine rotational speed, and adjusts the fuel injection amount. As a result, a constant engine speed is always maintained when the power generation engine 18 is operated, regardless of environmental conditions such as the atmospheric temperature and changes in the warm-up conditions of the power generation engine 18 and the generator 16. As a result, the rotational speed of the generator 16 is constant, and the fluctuation range of the power generation amount is very small, that is, the power generation amount of the generator 16 is substantially constant, so that the traveling battery 4 is not excessively charged or insufficiently charged. Therefore, the driving of the wheels 12 and 14 by the traveling motor 2 is not adversely affected.

Further, if a constant engine speed is maintained at all times, the output fluctuation range of the power generation engine 18 and the generator 16 depends only on the load fluctuation, and the output fluctuation range becomes narrower. Can be determined automatically. Therefore, the convergence of the control is improved, and the reliability of engine control and generator control is improved.
Furthermore, if an operation point with the same output can be uniquely determined, even the HCCI combustion with a narrow combustion establishment window can be executed easily.

The description of one embodiment of the present invention is finished above, but the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above embodiment, the engine ECU 24 controls diesel combustion and HCCI combustion, but instead of this HCCI combustion, control of premixed combustion located between diesel combustion and HCCI combustion is performed. It is also possible to do this.

  Specifically, in the engine ECU 24, the fuel injection timing is advanced by 30 ° BTDC, that is, compared with the above-described diesel combustion (range of about 20 ° BTDC to 5 ° ATDC) in accordance with the required rotational speed Ne of the hybrid ECU 22. However, it is retarded from about 120 ° BTDC as in HCCI combustion. Further, the compression ratio is lowered to a range of about 12 to 14 as compared with the diesel combustion (about 16 to 18). Furthermore, the EGR rate is increased to about 50% as compared with the diesel combustion (within about 20%). Further, the excess air ratio is lowered to about 1.25 compared to the diesel combustion (about 1.6).

  The combustion method is also a method in which the combustion establishment window is narrow, but can be established according to the control device of the present embodiment, and as a result, deployment to the vehicle is facilitated. Further, according to this combustion method, a lean fuel-air mixture is formed, and the combustion is performed at a low temperature, so that the generation of NOx and smoke is suppressed. In the case of this combustion method, the engine load can be limited. Therefore, in order to avoid engine stall, for example, the combustion injection amount may be increased when the rotational speed is reduced.

1 is a system configuration diagram to which a control device for a series hybrid vehicle according to an embodiment of the present invention is applied. It is a timing chart of the engine starting control of a generator and required accelerator opening control in the control device of FIG.

Explanation of symbols

2 Traveling motor (motor)
4 Battery for travel (battery)
6 Inverter 16 Generator (generator)
18 Power generation engine (internal combustion engine)
22 Hybrid ECU (hybrid control means)
24 ECU for engine (engine control means)
28 Accelerator sensor

Claims (2)

A generator,
An internal combustion engine that drives the generator;
A battery for traveling that is charged by the output of the generator;
A motor for running that is powered by the battery and drives the wheels;
Hybrid control means for controlling the generator and the motor;
Engine control means for controlling the internal combustion engine,
The hybrid control means outputs a required rotational speed for making the rotational speed of the internal combustion engine constant to the engine control means when the generator is driven based on an accelerator opening. Type hybrid vehicle control device. The hybrid control means outputs a rotational speed for achieving premixed combustion as the required rotational speed to the engine control means,
2. The control apparatus for a series hybrid vehicle according to claim 1, wherein the engine control means performs premixed combustion control based on the required rotational speed.

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