JPH0595102U - Booster negative pressure source confirmation control of electric motor for electric vehicle - Google Patents

Abstract

(57) [Summary] [Purpose] To provide an electric vehicle that can be normally driven only when the negative pressure source for operating the booster is normal and sufficient foot brake performance can be secured. [Configuration] A negative pressure source abnormality detection sensor 13 is provided in a negative pressure tank 3 that stores negative pressure supplied to a booster 2, and is connected to a control unit 11. Control unit 11
When the negative pressure source abnormality detection sensor 13 detects a pressure abnormality, the supply of the output current to the electric motor 9 is suppressed or stopped and the alarm lamp 14 is turned on.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to control of a driving motor of an electric vehicle that uses a negative pressure source formed by a vacuum pump by a foot brake booster, and more specifically, detects the abnormality of the negative pressure source to suppress the operation of the electric motor. This is related to the booster negative pressure source confirmation control of the electric motor for an electric vehicle that is stopped.

[0002]

[Prior Art]

 In order to respond to social demands such as energy saving and environmental problems, research and development of electric vehicles that use electric motors as drive sources to replace internal combustion engines have been promoted, and some have been put to practical use.

Therefore, a schematic configuration of the electric vehicle will be briefly described with reference to FIG. The electric vehicle 1 converts the electric energy stored in the storage battery 2 into a driving force by the electric motor 3 and transmits the driving force to the wheels 4 to run. The output current supplied to the electric motor 3 is adjusted by the control unit 5 in accordance with the accelerator opening degree (stepping amount) operated by the driver. The larger the current value, the larger the electric motor output and the vehicle speed. That is, the electric motor 3 corresponds to the engine of an internal combustion engine vehicle.

Further, the storage battery 2 corresponds to a fuel tank of an internal combustion engine vehicle, and receives the direct current obtained by converting the alternating current received from the general power source 6 by the charging device 7 to chemically store the electric energy. You can

The drive system for transmitting the driving force generated by the electric motor 3 to the wheels 4 is basically the same as that of an internal combustion engine vehicle, but the transmission can be omitted depending on the output characteristics of the electric motor. is there.

[0006]

The conventional electric vehicle described above is also provided with a booster (power booster) using negative pressure for the purpose of reducing the pedal effort of the foot brake. However, unlike an internal combustion engine vehicle that can utilize the engine suction negative pressure, an electric vehicle does not have a negative pressure source suitable for operating the booster, and therefore a vacuum pump or a negative pressure source for forming the negative pressure source is used. Tanks are installed.

Therefore, the object of the present invention is to prevent the foot brake performance from being sufficiently secured when the above-mentioned negative pressure source becomes abnormal and it becomes difficult to operate the booster. Another object of the present invention is to provide booster negative pressure source confirmation control of an electric motor for an electric vehicle, which suppresses or stops the supply of output current to the electric motor when an abnormality of the pressure source is detected.

[0008]

[Means for Solving the Problems]

 The present invention solves the above-mentioned problems, and in an electric vehicle in which a negative pressure source formed by a vacuum pump is stored in a negative pressure tank and a foot brake booster is operated using the negative pressure source, A negative pressure source abnormality detection sensor that operates when the negative pressure in the negative pressure tank becomes smaller than a predetermined value to detect a pressure abnormality, and a signal from the negative pressure source abnormality detection sensor and the accelerator opening sensor And a control unit for controlling an output current supplied to a driving electric motor, the control unit suppressing or stopping the supply of the output current when the negative pressure source abnormality sensor detects a pressure abnormality. This is a booster negative pressure source confirmation control for electric motors for electric vehicles.

[0009]

[Action]

 According to the above-mentioned means, when the negative pressure source abnormality detection sensor detects a pressure abnormality in the negative pressure tank, that is, when the negative pressure required to operate the booster cannot be secured, the control unit outputs the output current to the motor. Supply or stop the supply of. Therefore, the electric vehicle can run normally only when sufficient braking performance can be obtained with the assistance of the booster.

[0010]

【Example】

 An embodiment of a booster negative pressure source confirmation control of an electric motor for an electric vehicle according to the present invention will be described with reference to FIGS. 1 to 3.

In the system diagram of FIG. 1, a negative pressure tank 3 is connected to a booster 2 that reduces the pedal effort of a brake pedal 1, and the booster 2 is operated using a negative pressure source stored in the negative pressure tank. . This negative pressure source is formed by a vacuum pump 5 operated by an electric motor 4. The vacuum pump 5 has a negative pressure sensor (pressure switch) 6 provided in a negative pressure tank 3 for generating a negative pressure equal to or lower than a predetermined value. When detected, it is operated under the control of the vacuum pump controller 7. Reference numeral 8 denotes a master cylinder, and the hydraulic system connected to the brake device of each wheel is not shown.

On the other hand, the electric motor 9 for driving the electric vehicle outputs the output current from the electric motor drive circuit 12 provided in the control unit 11 in accordance with the accelerator opening signal input from the accelerator opening sensor 10 to the control unit 11. To be supplied. The accelerator opening sensor 10 detects a change in the resistance value according to the amount of depression of an accelerator pedal (not shown) operated by the driver. The larger the accelerator opening, the larger the output current supplied, and the higher the vehicle speed.

In the present invention, the negative pressure source abnormality detection sensor 13 provided in the negative pressure tank 3 is connected to the control unit 11 described above. Then, in the control unit 11, when the sensor 13 detects the pressure abnormality of the negative pressure tank 3, the supply of the output current to the electric motor 9 is suppressed or stopped, and the alarm lamp 14 indicating the content of the abnormality is turned on. To control. The negative pressure source abnormality detection sensor 13 may use a pressure switch that operates at a predetermined set pressure, and a buzzer or the like may sound at the same time when the alarm lamp 14 is turned on.

Next, the booster negative pressure source confirmation control in the control unit 11 first checks the negative pressure source stored in the negative pressure tank 3, as shown in the flow chart of FIG. As shown in FIG. 3, the negative pressure source is set so as to maintain the point a of −760 mmHg, for example, and when the negative pressure is reduced to the point b, the negative pressure sensor 6 detects it and turns off. The vacuum pump 5 is operated until the negative pressure rises to point a and the sensor is turned on again. Therefore, if the vacuum pump 5, the negative pressure sensor 6, etc. are operating normally, the negative pressure in the negative pressure tank 3 will not become lower than the point b. Therefore, the set pressure of the negative pressure source abnormality detection sensor 13 is set so that the pressure switch is turned off at the point d where the negative pressure is smaller than the point b (that is, close to the atmospheric pressure), and further, the points b and d. Hysteresis is provided so that it is turned on at an appropriate negative pressure point c between the point and. Therefore, when the negative pressure of the negative pressure tank 3 is smaller than the point d (predetermined value), it is determined that the negative pressure required to operate the booster of the foot brake cannot be secured, and the output current to the electric motor 9 is determined. The supply of is stopped (or suppressed) and the alarm lamp 14 is controlled to be turned on. When the negative pressure in the negative pressure tank 3 is equal to or higher than a predetermined value, the normal control is performed, and the output current according to the accelerator opening signal input from the accelerator opening sensor 10 is supplied to the electric motor 9.

That is, when there is not enough negative pressure to operate the booster 2 to reduce the pedal effort of the brake pedal 1, a large pedal effort is required to operate the foot brake, and in this case, the braking performance deteriorates. Is inevitable. However, if the booster negative pressure source confirmation control described above causes an abnormality in the negative pressure source pressure and the braking performance deteriorates, the negative pressure source abnormality detection sensor 13 detects this and the electric vehicle detects Since the vehicle is prohibited from traveling, it is possible to prevent a rear-end collision accident or the like caused by traveling without noticing a decrease in braking force. Alternatively, if the output current supplied to the electric motor 9 is suppressed prior to the accelerator opening signal and the vehicle speed is limited to the extent that the booster 2 can be easily stopped without the assistance of the booster 2, a rear-end collision accident or the like can be prevented. Not only can you do this, you can also drive to a safe place and stop.

[0016]

Effect of the Invention According to the booster negative pressure source confirmation control of the present invention described above, the state of the booster negative pressure source is constantly monitored by the negative pressure source abnormality confirmation sensor, and there is no abnormality in the pressure of the negative pressure source. Normal operation of the electric vehicle is possible only when the booster is activated to obtain excellent brake performance. That is, when sufficient braking force cannot be secured, traveling is prohibited by stopping the electric motor, or high-speed traveling is prohibited by suppressing the output current (vehicle speed limitation), so a rear-end collision accident can be prevented. This will have the effect of improving the reliability and safety of the electric vehicle.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

2 is a flowchart showing an example of booster negative pressure source confirmation control in the control unit of FIG. 1. FIG.

Fig. 3 ON / OFF of negative pressure sensor and negative pressure source abnormality detection sensor
It is a figure which shows the example of a relationship between OFF and negative pressure.

FIG. 4 is a block diagram showing a schematic configuration of an electric vehicle.

[Explanation of symbols]

 1 brake pedal 2 booster 3 negative pressure tank 5 vacuum pump 6 negative pressure sensor 7 vacuum pump controller 9 electric motor 10 accelerator opening sensor 11 control unit 13 negative pressure source abnormality detection sensor 14 alarm lamp

Front page continued (72) Inventor Hiroyasu Suzuki 5-3-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (72) Inventor Kazuo Natori 2-4-1, Nishitsujikeoka, Chofu-shi, Tokyo TEPCO Inside Technical Research Institute (72) Inventor Noboru Fujiwara 2-4-1 Nishi Tsutsujigaoka, Chofu City, Tokyo Inside Tokyo Electric Power Co., Inc. Technical Research Institute

Claims (1)

[Scope of utility model registration request] 1. An electric vehicle in which a negative pressure source formed by a vacuum pump is stored in a negative pressure tank, and a booster of a foot brake is operated by using the negative pressure source. A negative pressure source abnormality detection sensor that operates when it becomes smaller than a predetermined value to detect an abnormality in pressure, and an output current that is supplied to the driving electric motor by receiving signals from the negative pressure source abnormality detection sensor and the accelerator opening sensor And a control unit for controlling the
A booster negative pressure source confirmation control for an electric motor for an electric vehicle, characterized in that the supply of the output current is suppressed or stopped when a pressure abnormality is detected by the negative pressure source abnormality sensor.