JPH06245321A - Controller for engine driven generator in electric automobile - Google Patents

Abstract

PURPOSE:To prevent running feeling and emission level from degrading by making a decision whether the vehicle speed has been sustained within a predetermined range for a predetermined time or longer and sustaining a previous control target value of generating power if the answer is negative. CONSTITUTION:A vehicle speed decision means D decides whether the vehicle speed has been sustained within a predetermined range for a predetermined time or longer. If the answer is negative, a previous control target value is sustained. A generating power control means E controls power generated from an engine driven generator C based on such control target value. This constitution prevents the running feeling from degrading due to intermittent fluctuation of vibration/noise level of the engine driven generator C under a state where the vehicle speed varies frequently while furthermore preventing the emission level from lowering due to fluctuation of engine A load.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for controlling an engine-driven generator mounted on an electric vehicle, that is, a controller for an engine-driven generator for an electric vehicle.

[0002]

2. Description of the Related Art An electric vehicle is a vehicle having a motor as a drive source. As a means for supplying electric power for traveling to the motor, an on-board battery or an engine-driven generator can be used. The engine-driven generator has a configuration in which the mechanical output of the engine is input to the generator via a mechanism such as a gearbox, and the generated output is used for driving a motor and charging a battery. A vehicle having a system configuration in which an engine, a generator, and a motor are connected and connected in series in this way is called a series hybrid vehicle (SHV).

The power output of the engine-driven generator can be controlled by controlling the engine speed and the field current of the generator. Therefore, it is also possible to control the power generated by the engine-driven generator according to the power demanded by the motor, and eventually the running state of the vehicle (vehicle speed, etc.).
For example, in Japanese Patent Laid-Open No. 51-39813, a running state of a vehicle is detected, and a field current of the generator is controlled according to the detection result, so that the engine-driven generator of an engine-driven generator can be operated regardless of the running state of the vehicle. A technique for keeping the output substantially constant is disclosed.

[0004]

By applying such a technique, it is also possible to switch the power generation output of the engine-driven generator so that it increases when traveling at high speed and decreases when traveling at low speed. In this way, the engine-driven generator can operate in the power generation mode according to the vehicle speed. However, in such control, the vehicle starts / stops as if it were traveling in an urban area.
When the engine is stopped repeatedly, the power generation amount of the engine-driven generator frequently reciprocates between a low power generation state and a high power generation state. As a result, the vibration / noise level of the engine-driven generator changes intermittently, which deteriorates the driving feeling. Further, when the generated electric power of the engine-driven generator is switched by the field current of the generator, the load of the engine changes frequently, and the emission deteriorates.

To alleviate such a problem, for example, as shown in FIG. 7, control of the amount of power generated by the engine-driven generator may be executed so that it has a hysteresis characteristic with respect to the vehicle speed. That is, when the vehicle speed reaches or exceeds the predetermined threshold value V ₀₁ (t ₁ , t ₃ ), the amount of power generated by the engine-driven generator is increased, and the vehicle speed decreases and reaches or falls below the predetermined threshold value V _02. Then, (t ₂ , t ₄ ), the power generation amount may be switched to a small value. Note that v ₀₁ > v ₀₂ .

In this way, the amount of power generated by the engine-driven generator takes the same value as compared with the case where the determination relating to the vehicle speed is made with a single threshold value, that is, the case where no hysteresis characteristic is provided. Since the period becomes longer, the above-mentioned problems related to driving feeling and emissions are alleviated somewhat. However, even when such control is performed, the power generation amount is switched only when the vehicle is in a high speed state for a short time, and the driving feeling due to the intermittent fluctuation of the vibration and noise levels described above is caused. And the problem of emission deterioration due to fluctuations in engine load still remain.

The present invention has been made to solve the above problems, and in a situation where the vehicle speed changes frequently, the driving feeling due to the intermittent change of the vibration and noise level of the engine-driven generator. It is an object of the present invention to more appropriately prevent the deterioration of the engine, the deterioration of the emission level due to the fluctuation of the engine load, and the like.

[0008]

In order to achieve such an object, the control device of the present invention has a structure as shown in FIG. That is, the present invention is mounted on an electric vehicle equipped with an engine-driven generator C having an engine A and a generator B that is driven by the mechanical output of the engine A to generate electric power for driving the vehicle. In a control device that controls the power generated by the engine-driven generator C according to the state, a vehicle speed determination means D that determines whether the vehicle speed is continuously within a predetermined range for a predetermined time or longer, and the above determination is established. If so, the control target value is switched to a value according to the vehicle speed, and if not satisfied, the generated power control means for controlling the generated power of the engine-driven generator C while maintaining the control target value at the previous value. E and E are provided.

[0009]

In the present invention, first, the vehicle speed determination means D determines whether or not the vehicle speed is continuously within a predetermined range for a predetermined time or longer. As a result of this determination, when it is determined that the vehicle speed is continuously within the predetermined range for the predetermined time or more, the control target value is switched to a value according to the vehicle speed. vice versa,
When the condition related to the above determination is not satisfied, for example, when the time when the vehicle speed is within the predetermined range has not continued for the predetermined time by the present time, the control target value is maintained at the previous value. The generated power control means E controls the generated power of the engine-driven generator C based on such a control target value. Therefore, in the present invention, when the vehicle speed exceeds a predetermined value for a very short time, such as when the vehicle is traveling in an urban area, the power generated by the engine-driven generator is maintained at a smaller value than before. To be done. As a result, it is possible to prevent the driving feeling from being deteriorated due to the intermittent change of the vibration / noise level. Further, when the control of the generated power is executed as the control of the field current of the generator B, the load fluctuation of the engine A is suppressed, and the deterioration of the emission is prevented.

[0010]

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

FIG. 2 shows an SHV according to an embodiment of the present invention.
The system configuration of is shown. The system shown in this figure comprises a motor 14 connected to drive wheels 12 via a transaxle 10 or the like. The motor 14 is a three-phase AC induction motor, and is driven by the three-phase AC power supplied from the inverter 16. The inverter 16 is
DC power supplied from the battery 18 or the rectifier 20 is E
It is converted into three-phase AC power under the control of the CU 22 and supplied to the motor 14. That is, the ECU 22 inputs a vehicle signal indicating an accelerator operation, a brake operation, and the like of the vehicle operator, and the rotation speed sensor 2 attached to the motor 14
The rotation speed N of the motor 14 is detected by 4, and the torque command value is calculated based on these. The torque command value is the motor 14
Shows the value of the torque to be output from the ECU2.
2 indicates the PW of the switching operation of the plurality of switching elements forming the inverter 16 according to the torque command value.
M control. This allows the vehicle operator to operate the accelerator,
The output torque corresponding to the brake operation or the like is obtained from the motor 14.

The rectifier 20 is a circuit that rectifies the power output of the engine-driven generator 26. Engine driven generator 2
The reference numeral 6 includes an engine 28, a speed increasing gear 30, and a generator 32. The output shaft of the engine 28 is connected to the generator 32 via the speed increaser 30, and the generated output (three-phase AC power) of the generator 32 is rectified by the rectifier 20. The output of the rectifier 20 is supplied to the inverter 16 and used as driving power for the motor 14, and is also used for charging the battery 18 in a predetermined case. In addition, gearbox 3
0 is a device for increasing the output speed of the engine 28 to a speed suitable for the input of the generator 32.

The ECU 22 executes the control of the engine-driven generator 26 in addition to the control of the inverter 16 described above. That is, while controlling the throttle opening of the engine 28, controls the field current I _f of the generator 32.
In this embodiment, the ECU 22 uses the rotation speed N of the motor 14 obtained by the rotation speed sensor 24 and the state of charge (SOC) of the battery 18 obtained by the SOC meter 34 attached to the battery 18 in this control.

FIG. 3 shows the ECU 22 in this embodiment.
Of the power generation mode, in particular, the operation of switching the power generation mode by the interruption from the timer built in the ECU 22.

When a timer interrupt occurs in the ECU 22, the ECU 22 first determines whether or not the SOC of the battery 18 exceeds a predetermined value α. As a result SOC>
When it is set to α, the ECU 22 executes step 102, puts the engine-driven generator 26 in the power generation stop state, and then ends the operation related to the timer interruption. Conversely, SO
If it is determined that C ≦ α, the ECU 22 executes step 1
The operation shifts to 04 and later.

In step 104, the ECU 22
Determines whether SOC <β. If the result of this determination is SOC ≧ β, the ECU 22 determines in step 1
Execute 06. In this step 106, EC
U22 determines whether or not the engine-driven generator 26 is in the power generation stopped state, for example, based on the field current _If or the like. When this determination is satisfied, that is, when the engine-driven generator 26 is in the power generation stopped state, the ECU 22 ends the operation related to the timer interruption. On the contrary, if it is determined that the power generation is not stopped, SOC <β in step 104.
As in the case of the above, the process proceeds to step 108.

In step 108, the ECU 22
Determines whether the vehicle is currently in a low speed traveling state and whether this low speed traveling state continues for a predetermined value T ₁ (ms) or more. For example, it is determined whether the vehicle is traveling at low speed or high speed based on the rotation speed N of the motor 14, and when traveling at low speed, the built-in timer counts the continuous time up to the present time, Step 108 is executed based on the results of these judgments and counting. When this determination is established, that is, when the low speed running state is T
If it continues for ₁ (ms) or more, the process proceeds to step 110, and if not satisfied, the process proceeds to step 112.

In step 112, the vehicle is in a high-speed traveling state, and this high-speed traveling state is a predetermined value T ₂ (m
s) It is determined whether or not the above is continuous. When this determination is satisfied, that is, when the vehicle is in the high-speed traveling state and the high-speed traveling state is continuous for T ₂ (ms) or more, the ECU 22 executes step 114. If this determination is not established, step 10
Step 110 is executed similarly to the case where the determination of 8 is established. Also in step 112, the rotation speed N of the motor 14, for example, is used as the information relating to the vehicle speed and the like, and the continuous time in the high-speed traveling state is counted by the timer incorporated in the ECU 22.

In step 110, the ECU 22
Controls the number of revolutions of the generator 32 to a small value and sets the power generated by the engine-driven generator 26 to a smaller value. That is, the power generation mode of the engine-driven generator 26 is set to the low power generation mode. Conversely, in step 114, the ECU
22 sets the rotation speed of the generator 32 to a higher value, and sets the generated power of the engine drive generator 26 to a larger value. That is, the power generation mode of the engine-driven power generator 26 is set to the high power generation mode. After these steps 110 or 114 are executed, the operation related to the timer interrupt ends.

In the operation described above, step 10
0 to 106 represent switching of the power generation state by SOC, and particularly its hysteresis characteristic. The aforementioned predetermined values α and β
Is set to an SOC value such that the drive power of the motor 14 can be supplied only by the battery 18, and α> β.

First, at some point, the SOC of the battery 18 becomes SO
When C> α, the engine-driven generator 26 is stopped in the power generation state as described above (102), and then the battery 1
Even if the discharge of 8 progresses, (10
4), the engine-driven generator 26 maintains the power generation stopped state (106).

On the contrary, at some point, the SOC of the battery 18 becomes SO
If C <β, step 110 or 114 is executed and the battery 18 is charged.
≧ β. In this case, since step 110 or 114 was executed when the timer interrupt occurred last time, the determination related to step 106 is not established, and step 1
The power generation operation by 10 or 114 is continued. After that, only when the SOC reaches SOC> α, the state of the engine-driven generator 26 becomes the power generation stopped state. As a result, the hysteresis characteristic is realized as shown in FIG.

The determination in steps 108 and 112 is based on the operation according to the characteristic of this embodiment, that is, the operation of not switching the power generation mode of the engine-driven generator 26 when the vehicle speed increases / decreases for a short time. Has been realized.

First, in Steps 108 and 112, it is determined whether the engine speed is low or high, respectively, so that the engine-driven generator 26 of the engine-driven generator 26 is operated according to the vehicle speed as shown in FIG. The generated power (power generation amount) can be switched. However, in this figure, V ₀ is a threshold value for determining whether it is low speed or high speed in steps 108 and 112, and is set to a value of about 60 km / h, for example.

At the same time, in steps 108 and 112, determinations relating to the continuous time in the low speed running state and the continuous time in the high speed running state are executed. In other words, even if the vehicle is running at a low speed, this state remains for a predetermined time T ₁ (ms).
When the above is not continuous or when the vehicle is in a high speed running state and this state is not continuous for T ₂ (ms) or more, power generation in the conventional power generation mode is executed. Therefore, for example, as shown in FIG. 6, the times t ₂ ′ −t ₁ and t at which the vehicle speed is equal to or higher than the predetermined value V _0.
If ₄ '-t ₃ is shorter than the predetermined value T _2, the power generation by conventional power generation mode, that is, the power generation of a smaller amount of power generation by the low power mode is continued.

As described above, according to the present embodiment, even when the vehicle is traveling in an environment in which starting and stopping are frequently repeated, such as an urban area, the power generation mode switching is frequently repeated. As a result, the driving feeling deteriorates due to frequent changes in vibration and noise levels, and the engine 2
Emissions will not be deteriorated due to the load fluctuation of item 8.
As a result, an SHV having a better driving feeling and a better emission can be realized.

In the above description, the information on the vehicle speed is input to the ECU 22 as the rotation speed N of the motor 14, but this may be input by other means. Further, the predetermined values T ₁ and T ₂ used for the determination relating to the continuous time in steps 108 and 112 may be set to equal values, but when considering reduction of vibration and noise, T ₁ > It is preferable to set it to T ₂ . Further, in the above description, two power generation modes, the low power generation mode and the high power generation mode, are set as the power generation modes of the engine-driven power generator 26, but a larger number of modes may be used.

[0028]

As described above, according to the present invention,
Since it is determined whether the vehicle speed is continuously within the predetermined range for a predetermined time or longer, and if this determination is not established, the control target value of the generated power is maintained at the previous value, the vehicle speed is frequently changed. Even under changing conditions, it is possible to prevent the driving feeling from deteriorating due to intermittent changes in vibration and noise levels. Further, when the control of the generated power is executed as the control of the field current of the generator B, the deterioration of the emission level due to the load change of the engine A can be prevented.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of the present invention.

FIG. 2 is a block diagram showing a system configuration of an SHV according to an embodiment of the present invention.

FIG. 3 is a flowchart showing a flow of operation of an ECU in this embodiment.

FIG. 4 is a diagram showing a switching operation of a power generation state by SOC.

FIG. 5 is a diagram showing a power generation amount switching operation depending on a running state of a vehicle.

FIG. 6 is a diagram showing a characteristic operation of this embodiment, FIG. 6 (a) is a diagram showing a change in vehicle speed, and FIG. 6 (b) is a diagram showing a power generation amount.

FIG. 7 is a diagram showing a conventional problem, FIG. 7 (a) is a diagram showing a change in vehicle speed, and FIG. 7 (b) is a diagram showing a change in power generation amount.

[Explanation of symbols]

A, 28 engine B, 32 generator C, 26 engine drive generator D vehicle speed determination means E generated power control means 14 motor 18 battery 22 ECU 24 rotation speed sensor 34 SOC meter N motor rotation speed (vehicle speed) SOC battery charging State I _f Field-currents of generator α, β Judgment threshold value for SOC SOC V ₀ Judgment threshold value for vehicle speed T ₁ , T ₂ Judgment threshold value for continuous time of vehicle running state

Claims (1)

[Claims] 1. An electric vehicle equipped with an engine-driven generator having an engine and a generator that is driven by the mechanical output of the engine to generate electric power for driving the vehicle. The engine is mounted according to the running state of the vehicle. In the control device for controlling the generated power of the drive generator, the vehicle speed determining means for determining whether the vehicle speed is continuously within a predetermined range for a predetermined time or more, and a control target value when the above determination is established. To a value according to the vehicle speed, and if not satisfied, the generated power control means for controlling the generated power of the engine-driven generator while maintaining the control target value at the previous value. Control device.