JPH07336809A - Control method of series hybrid vehicle - Google Patents

Abstract

PURPOSE:To obtain a control method in which the running operation of a vehicle can be continued even when a battery cannot function normally and which prevents an emission from being worsened due to a sudden increase in an engine speed. CONSTITUTION:When a battery voltage Vb becomes abnormal (102), a generator controller decides a target engine speed Ne* according to an accelerator opening Acc (206), a vehicle controller corrects a torque instruction T* in such a way that an engine speed Ne becomes the target engine speed Ne*, and it outputs the torque instruction to a motor controller (108). Since a generator output and the engine speed are controlled according to an output required by a motor, the blowup of the engine speed Ne due to the loss of an engine balance not generated. In addition, when a change in an engine output is decreased as compared with a change in the accelerator opening Acc, it is possible to prevent an emission from being worsened due to a sudden change in the engine speed Ne.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control method for a series hybrid vehicle including a traveling motor, a battery and an engine-driven generator.

[0002]

2. Description of the Related Art A series hybrid vehicle is a vehicle that can utilize both the discharge output of a battery and the power output of an engine-driven generator when driving a traveling motor. That is, the traveling motor can be driven by the discharge output of the battery even when the engine-driven generator is not operating, and in addition to the discharge output of the battery when the engine-driven generator is operating, The power generation output can also be used to drive the traveling motor. Also,
The power output of the engine driven generator can also be used to charge the battery.

[0003]

However, the battery is
It may not function normally due to overvoltage or life, and may not be in a chargeable state. When such a situation occurs, only the power output of the engine-driven generator can be used to drive the traveling motor. At this time, if the output of the traveling motor is less than the output of the engine-driven generator, the energy balance may be lost and the rotation speed of the engine that constitutes the engine-driven generator may increase. When such a state is reached, it is necessary to stop the engine. However, when the engine is stopped, the drive power supply to the motor is cut off and the vehicle cannot continue to run.

The present invention has been made to solve the above problems, and even if the battery fails to function normally for some reason, the engine speed increases due to the loss of energy balance. It is an object of the present invention to provide a control method that does not occur and can therefore continue the traveling of the vehicle. Another object of the present invention is to prevent deterioration of emission at that time.

[0005]

In order to achieve such an object, the present invention provides a traveling motor, a battery supplying a discharging output to the traveling motor, and a discharging output to the traveling motor and the battery. In a series hybrid vehicle equipped with an engine-driven generator, it is determined whether the battery is in a chargeable state, and when it is in a chargeable state, the output required for the traveling motor and the charge state of the battery The target power generation amount is determined based on the output of the engine drive generator when the chargeable state is not reached, and the target power generation amount is determined based on the output required for the traveling motor. It is characterized by controlling the power generation output.

Further, the present invention is characterized in that when the battery is not in a chargeable state, the target power generation amount is gradually changed as compared with the change in output required for the traveling motor.

[0007]

In the present invention, first, it is determined whether or not the battery is in a chargeable state. When it is determined that the vehicle is in a chargeable state, the target power generation amount is determined based on the output required for the traveling motor and the state of charge of the battery. Furthermore, once the target power generation amount is determined,
The power output of the engine-driven generator is controlled with the determined target power generation amount as a target. Therefore, in this case, the power generation output of the engine-driven generator becomes the output required for the traveling motor and the output according to the state of charge of the battery. On the contrary, when the battery is not in the chargeable state, the target power generation amount is determined based on the output required for the traveling motor. Once the target power generation is determined,
Similarly, the power generation output of the engine-driven generator is controlled with this target power generation amount as a target. Therefore, in this case, the power generation output of the engine-driven generator is controlled based on the output required for the traveling motor. As described above, in the present invention, when the battery does not function normally and cannot be charged, the power generation output corresponds to the output of the traveling motor, so that the engine speed of the engine constituting the engine-driven generator is reduced. There is no problem such as rising, so that the vehicle can continue to be driven by the engine-driven generator.

Further, in the present invention, when the battery is not in the chargeable state, the target power generation amount gradually changes compared with the change in output required for the traveling motor. Therefore, the sudden change in the target power generation amount, and consequently, the emission deterioration due to the rapid change in the engine output will not occur.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the system configuration of a series hybrid vehicle according to an embodiment of the present invention. The series hybrid vehicle shown in this figure uses a three-phase AC motor as the traveling motor 10.

The drive power of the motor 10 is the inverter 12
It is supplied from the battery 14 via the. That is, when the switch 17 is on, the discharge output of the battery 14 is supplied to the inverter 12 and converted into three-phase AC power. This three-phase AC power is supplied to the motor 10 to drive the motor 10 to rotate.

The drive power of the motor 10 can be obtained not only from the battery 14 but also from the engine-driven generator composed of the engine 16 and the generator 18. The output shaft of the engine 16 is connected (if necessary via a gearbox or the like) to a generator 18 and thus the engine 16
Is operated and the field current If is supplied to the generator 18, AC power is obtained from the generator 18. This electric power, that is, the generator output P _Gen is rectified by the rectifier 20 in the subsequent stage and converted into DC power. This power is converted into three-phase AC power by the inverter 12 and used as drive power for the motor 10, and also used for charging the battery 14 when the switch 17 is on.

In this embodiment, a vehicle controller 22, an engine controller 24, a generator controller 26 and a motor controller 28 are provided as means for controlling each part of the system. Vehicle controller 2
2 is the accelerator pedal depression amount by the vehicle operator,
That is, the torque command T ^* is determined based on the accelerator opening Acc, and the torque command T ^* is supplied to the motor controller 28. The motor controller 28 uses the rotation sensor 30 to detect the rotation speed N of the motor 10, and the current sensor 34 to detect the rotation speed N
While detecting the current I _M of 0, the torque command T
^A PWM (pulse width modulation) signal is generated according to ^* , and this is supplied to each switching element forming the inverter 12. Each switching element forming the inverter 12 is turned on / off by this PWM signal. Therefore, the output torque of the motor 10 becomes a value corresponding to the torque command T ^*, and the output of the motor 10 becomes a value determined by the torque command T ^* and the rotation speed N.

The engine controller 24 is the engine 1
6, the injection amount, the ignition timing, etc. are controlled. That is,
The engine 16 is operated with a wide open throttle (WOT) as shown in FIG. 2, and its output is uniquely determined when the engine speed N _e is determined. Further, since the output P _Gen of the generator 18 corresponds to the engine output, by targeting the engine speed N _e ,
Target control of the generator output P _Gen is possible.

The generator controller 26 has a generator output P.
It is a means for controlling the target of _Gen. That is, while the battery 14 is operating normally and the switch 17 is closed, the generator controller 26 inputs the motor output (specifically, its average value) P _MOT from the motor controller 28 as information. While detecting the power generation output voltage V and the power generation output current I by the voltage sensor 32 and the current sensor 34, an engine start signal is given to the engine controller 24 to start the engine 16 as needed, and the field of the generator 18 is also detected. Control the current _If . That is, the generator controller 26 can know from the motor output _PMOT corresponding to the output required for the traveling motor and the power generation output voltage V (in this case, equal to the battery voltage Vb), the state of charge of the battery 14. Based on
The target generator output is determined, and further the target engine speed N _e ^* is determined. The generator controller 26
The field current _If is controlled so that the engine speed N _e becomes the target engine speed N _e ^* , whereby the generator output P
Target control of _Gen (see FIG. 3).

However, such an operation is performed by the battery 14
Is difficult to implement if is unable to function properly.
That is, when the battery 14 cannot function normally, the drive power of the motor 10 is _covered by the generator output P _Gen of the engine-driven generator, and thus the motor 1
The driving power of 0 is the generator output P _G of the engine-driven generator.
If it is smaller than _en , the energy balance may be lost and the engine speed N _e may increase. Therefore, in this embodiment, the battery voltage V detected by the voltage sensor 36 indicates whether or not the battery 14 is functioning normally.
It is determined by the vehicle controller 22 based on _b . The vehicle controller 22 issues a control switching signal when it detects an abnormality in the battery voltage _Vb , opens the switch 17, and switches the operations of the vehicle controller 22 and the generator controller 26.

FIG. 4 shows the operation flow of the vehicle controller 22 and the generator controller 26 in this embodiment. As shown in this figure, the battery 14
Is normally functioning, that is, the battery 14 can be charged, the vehicle controller 22 determines the torque command T ^* according to the accelerator opening Acc and outputs it to the motor controller 28 (100). When the battery voltage _Vb becomes an abnormal value (102), the vehicle controller 2
2 turns on the control switching signal and supplies it to the switch 17, the engine controller 24 and the generator controller 26. Before the control switching signal is turned on, the generator controller 26 sets the target power generation amount according to the motor output _PMOT, etc.
Consequently, the target engine speed N _e ^* is determined (20
0), the engine speed N _e is the target engine speed N _e ^*
The field current _If is controlled to be (202). When the control switching signal is turned on by the vehicle controller 22, the generator controller 26 responds (20
4) Switch the control operation. That is, the target engine speed N _e ^* is determined according to the accelerator opening degree Acc corresponding to the output required for the traveling motor and is output to the vehicle controller 22 (206).

After turning on the control switching signal, the vehicle controller 22 determines the torque command T according to the accelerator opening Acc.
^{* Is} determined (106). The vehicle controller 22 further receives the target engine speed N _e ^* from the generator controller 26 and corrects the determined torque command T ^* so that the engine speed N _e becomes the target engine speed N _e ^*. Is output to the motor controller 28 (10
8). When the torque command T ^* is output to the motor controller 28 and the motor output control based on the torque command T ^* is performed, the generator output P _Gen is controlled to be equal to the motor output. Further, in this state, as shown in FIG. 5, the output voltage V of the generator 18 is controlled by the field current _If .

After that, when the reset signal is input, the vehicle controller 22 turns off the control switching signal accordingly. That is, when the battery 14 has been repaired or the like and the battery 14 has returned to a normal state, the repair person or the like supplies a reset signal to the vehicle controller 22 to turn off the control switching signal (112). Then, in response to this, the operation of the vehicle controller 22 and the generator controller 26 is the operation when the battery 14 is normal, that is, step 1
The operation shifts to 08 and 200 or later (112, 20
8).

Therefore, according to this embodiment, the battery 14
Is no longer able to function normally, the generator output P _Gen will be controlled according to the output required of the motor 10, so that the energy balance will not be disturbed and the engine speed N _e will not rise. . Therefore, the battery 1
It is possible to continue traveling even when 4 cannot function normally.

Further, in this embodiment, FIG.
As shown in (b), the smoothing control of the engine output is performed. That is, when the target engine speed N _e ^* is determined in step 206, a moderation b that is more gradual than the change a of the accelerator opening Acc is added. Then, as a result of the output of the torque command T ^* in step 108, the engine output becomes a gradual change b as compared to the change a of the accelerator opening Acc as shown in FIG. 6 (b). When such a moderation is given, the engine speed N
_e does not change rapidly, and therefore the engine speed N _e
It is possible to prevent the emission from deteriorating due to a sudden change in Of course, the present invention does not exclude the control as shown in FIG. 6A, that is, the control in which the time constants relating to the change a of the accelerator opening Acc and the change b of the engine output substantially match.

[0022]

As described above, according to the present invention,
Since the target power generation amount is determined based on the output required for the traveling motor when the battery is not in the chargeable state, the energy balance is prevented from being lost, and the engine speed is not increased. Therefore, the vehicle can continue to run.

Further, according to the present invention, when the battery is not in the chargeable state, the target power generation amount is gradually changed as compared with the change in the output required for the traveling motor. The sudden rise in numbers disappeared,
Therefore, deterioration of emission can be prevented.

[Brief description of drawings]

FIG. 1 is a block diagram showing a system configuration of a series hybrid vehicle according to an embodiment of the present invention.

FIG. 2 is a diagram showing generator output characteristics during WOT in this example.

FIG. 3 is a diagram showing the content of control of a generator output P _Gen by a field current I _f .

FIG. 4 is a flowchart showing an operation flow of a vehicle controller and a generator controller in this embodiment.

FIG. 5 is a diagram showing the content of control of a generator output voltage V by a field current _If .

FIG. 6 is a diagram for explaining moderating control of engine output.

[Explanation of symbols]

10 Motor 12 Inverter 14 Battery 16 Engine 18 Generator 22 Vehicle Controller 24 Engine Controller 26 Generator Controller 28 Motor Controller Acc Accelerator Opening T ^* Torque Command P _MOT Motor Output N _e Engine Speed N _e ^* Target Engine Speed _If Field current _Vb Battery voltage

Claims (2)

[Claims] 1. A series hybrid vehicle including a traveling motor, a battery that supplies a discharge output to the traveling motor, and an engine-driven generator that supplies a generated output to the traveling motor and the battery, and the battery is in a chargeable state. The step of determining whether there is a charge, the step of determining the target power generation amount based on the output required for the traveling motor and the state of charge of the battery when the battery is in a chargeable state, If there is not, a step of determining a target power generation amount based on the output required for the traveling motor, and a step of controlling the power generation output of the engine-driven generator with the determined target power generation amount as a target are included. Characteristic control method. 2. The control method according to claim 1, wherein when the battery is not in a chargeable state, the target power generation amount is gradually changed compared to the change in output required for the traveling motor. And control method.