Pneumatic braking system of pure electric vehicle

Abstract

The utility model discloses an air pressure braking system of a pure electric vehicle, which comprises a vehicle control unit, a brake master pump module connected with the vehicle control unit, a BMS (Battery Management System) module, an MCU (Microprogrammed Control Unit) module connected with a motor, an air cylinder and an electromagnetic valve connected with the vehicle control unit, one end of the air cylinder is connected with a control port of the relay valve after sequentially passing through the brake master pump module and the electromagnetic valve, an air source interface of the relay valve is connected with the other end of the air cylinder, and an air outlet of the relay valve is connected with a brake chamber of a wheel; normal work of the brake system can be guaranteed.

Description

TECHNICAL FIELD

[0001] The utility model relates to pure electric vehicle technical field, especially a pure electric vehicle air pressure braking system. BACKGROUND

[0002] Pure electric vehicle is to improve its endurance mileage and economy, and the kinetic energy of the vehicle is recycled when the vehicle brakes, the motor is converted from driving mode to generator mode, and the reverse output current is output to the battery, realizing the braking energy recovery. The motor in the energy recovery state provides braking force for the whole vehicle.

[0003] At present, many feedback braking systems cannot perform electric feedback when the battery SOC value of the whole vehicle is greater than 90% in order to ensure the safety of the power battery, at which time the driver who normally operates and measures will find that the braking energy of the whole vehicle suddenly disappears, affecting the driving experience.

[0004] At present, the brake pedal used by the pure electric vehicle using air pressure braking has a 30% idle stroke, and there is no air pressure braking in the driving range. In order to ensure the braking recovery energy, only the motor provides braking ability, and when the SOC value is greater than 90, the electric braking disappears, and the air pressure braking intervention idle stroke is too large, affecting the braking experience.

[0005] Many feedback braking systems usually do not consider running in a high state of charge in order to ensure charging safety, and the starting threshold value of the feedback braking function is usually limited to below 90% of the battery SOC value of the whole vehicle. The document with publication number CN 105774566A discloses a braking energy feedback control method for a pure electric vehicle, and the control method considers that the battery SOC value is in the interval of 20%-80%. The document with publication number CN 108001240A discloses a braking energy recovery system, and the designed energy feedback system no longer charges the lithium ion battery when the battery SOC value is higher than 90%, and a heating resistor is used at high SOC to consume feedback energy, prevent the motor from charging the power battery, or a retarder is used, and the retarder works at high SOC to ensure braking performance. The electric braking feedback is abandoned, at which time the driver will feel that the brake suddenly disappears when stepping on the brake, the driving experience is poor, and the driver will be panic; the electric eddy current retarder is used, and the electric eddy current retarder is used to replace the electric feedback brake when there is no electric feedback brake, the cost of the whole vehicle is high, and the installation difficulty is great. UTILITY MODEL CONTENTS

[0006] To solve the problems in the prior art, the purpose of the utility model is to provide a pure electric vehicle air pressure braking system, which can ensure the normal work of the braking system.

[0007] In order to achieve the above object, the utility model discloses technical scheme is: a pure electric vehicle pressure brake system, including the vehicle controller, with the vehicle controller connection brake master pump module, BMS module and MCU module, the MCU module is connected with motor, still include the air cylinder and with the vehicle controller connection electromagnetic valve, the air cylinder one end is connected with the control port of follow -up valve after the brake master pump module and electromagnetic valve, follow -up valve gas source interface is connected with the other end of air cylinder, and the air outlet of follow -up valve is connected with the brake chamber of wheel.

[0008] As a further improvement of the utility model, the electromagnetic valve is an ABS electromagnetic valve.

[0009] As a further improvement of the utility model, the ABS electromagnetic valve includes a front axle ABS electromagnetic valve and a rear axle ABS electromagnetic valve, the air cylinder includes a front axle air cylinder and a rear axle air cylinder, the follow-up valve includes a front axle follow-up valve and a rear axle follow-up valve, and the brake chamber includes a front axle brake chamber and a rear axle brake chamber; one end of the front axle air cylinder is connected with the control port of the front axle follow-up valve after the brake master pump module and the front axle ABS electromagnetic valve, the gas source interface of the front axle follow-up valve is connected with the other end of the front axle air cylinder, and the air outlet of the front axle follow-up valve is connected with the front axle brake chamber of the wheel; one end of the rear axle air cylinder is connected with the control port of the rear axle follow-up valve after the brake master pump module and the rear axle ABS electromagnetic valve, the gas source interface of the rear axle follow-up valve is connected with the other end of the rear axle air cylinder, and the air outlet of the rear axle follow-up valve is connected with the rear axle brake chamber of the wheel.

[0010] As a further improvement of the utility model, the BMS module and the MCU module are connected with the vehicle controller through a CAN bus.

[0011] The utility model discloses the beneficial effect is:

[0012] The utility model discloses through using small air stroke brake master pump module, this module is generally used in electric control brake EBS system, it has small air stroke, can provide voltage signal used to electric car simultaneously, when SOC is less than 90 %, the system is same as conventional electric car, when SOC is greater than 90 %, can trigger the conventional gas brake circuit of system, guarantees that brake system can normally work. ACCOUT OF DRAWINGS

[0013] Figure 1 It is the electric control system principle drawing of the utility model embodiment;

[0014] Figure 2 It is the gas circuit principle drawing of the utility model embodiment;

[0015] Figure 3 It is the working principle flow chart of the utility model embodiment.

[0016] Reference signs:

[0017] 1, brake master cylinder module, 2, BMS module, 3, front axle ABS solenoid valve, 4, rear axle ABS solenoid valve, 5, MCU module, 6, vehicle controller, 7, motor, 8, front axle relay valve, 9, rear axle relay valve, 10, front axle brake chamber, 11, rear axle brake chamber, 12, front axle air reservoir, 13, rear axle air reservoir. DETAILED DESCRIPTION

[0018] The embodiments of the utility model will be described in detail below with reference to the drawings.

[0019] Embodiments

[0020] Related terms are explained:

[0021] Relay valve: 1 control port 4, 1 air source interface 1, 2 air outlets 2.

[0022] ABS solenoid valve: 1 air inlet 1 and 1 air outlet 2 and 1 exhaust port 3, normal ABS solenoid valve has the functions of pressure increasing, pressure maintaining and pressure relief, and this embodiment only uses the functions of pressure increasing and pressure relief, that is, when not powered, the air inlet 1 and the air outlet 2 are always on, and when pressure relief, the air outlet 2 and the exhaust port 3 are on, realizing rapid pressure relief.

[0023] Brake master cylinder module: connected with brake pedal, when stepping on brake pedal, master cylinder can input continuous voltage analog signal, the analog signal is provided to vehicle controller, and there are two pairs of independent air inlets and outlets, air inlet 11, air outlet 21 and air inlet 12, air outlet 22.

[0024] Air reservoir: store compressed air, air source provided by air compressor is dried by dryer and injected into air reservoir, this part is general technology in the industry, which is not expanded.

[0025] BMS module: power battery management system, provides battery power state SOC to vehicle VCU.

[0026] MCU module: motor controller, receives vehicle controller instructions, controls motor speed and forward and reverse rotation.

[0027] For example, Figure 1 And Figure 2As shown, a pure electric vehicle air pressure braking system includes a vehicle controller 6, a brake master cylinder module 1, a BMS module 2, and an MCU module 5 connected to the vehicle controller 6. The MCU module 5 is connected to a motor 7. The system also includes an air reservoir and a solenoid valve connected to the vehicle controller 6. One end of the air reservoir is connected to the control port of a relay valve after passing through the brake master cylinder module 1 and the solenoid valve in sequence. The air source interface of the relay valve is connected to the other end of the air reservoir, and the air outlet of the relay valve is connected to the brake chamber of the wheel. The solenoid valve is an ABS solenoid valve.

[0028] In this embodiment, the ABS solenoid valves include a front axle ABS solenoid valve 3 and a rear axle ABS solenoid valve 4; the air reservoirs include a front axle air reservoir 12 and a rear axle air reservoir 13; the relay valves include a front axle relay valve 8 and a rear axle relay valve 9; and the brake chambers include a front axle brake chamber 10 and a rear axle brake chamber 11. One end of the front axle air reservoir 12 is connected sequentially via the brake master cylinder module 1 and the front axle ABS solenoid valve 3, and then to the control port of the front axle relay valve 8. The air source interface of the front axle relay valve 8 is connected to the other end of the front axle air reservoir 12, and the air outlet of the front axle relay valve 8 is connected to the front axle brake chamber 10 of the wheel; one end of the rear axle air reservoir 13 is connected to the control port of the rear axle relay valve 9 after passing through the brake master cylinder module 1 and the rear axle ABS solenoid valve 4 in sequence, and the air source interface of the rear axle relay valve 9 is connected to the other end of the rear axle air reservoir 13, and the air outlet of the rear axle relay valve 9 is connected to the rear axle brake chamber 11 of the wheel.

[0029] The working principle of this embodiment is explained below:

[0030] like Figure 3 As shown, during the operation of the pure electric vehicle, the BMS module 2 synchronizes the SOC value of the power battery to the vehicle controller 6 in real time via the CAN bus. When the battery SOC is greater than 90%, and the brake pedal is pressed, the V3 and V4 pins of the vehicle controller 6 have no voltage output, and the front axle ABS solenoid valve 3 and the rear axle ABS solenoid valve 4 are de-energized and connected. At this time, the compressed air from the front axle air reservoir 12 passes through the air inlet 12 and air outlet 22 of the brake master cylinder module 1, through the front axle ABS solenoid valve 3, and reaches the front axle relay valve 8. The 4 ports control the 1 port of the front axle relay valve 8 to send the compressed air in the front axle air reservoir 12 to the front axle brake chamber 10 through the 2 port of the front axle relay valve 8, thereby achieving front wheel braking. At the same time, the compressed air in the rear axle air reservoir 13 passes through the air inlet 11 and air outlet 21 of the brake master cylinder module 1, and through the rear axle ABS solenoid valve 4 to reach the 4 port of the rear axle relay valve 9. The 1 port of the rear axle relay valve 9 controls the 2 port of the rear axle relay valve 9 to send the compressed air in the rear axle air reservoir 13 to the rear axle brake chamber 11, thereby achieving rear wheel braking.

[0031] When the battery's state of charge (SOC) is no greater than 90%:

[0032] 1、When the brake pedal is pressed to 30% of the pedal stroke, the V3 and V4 pins of the vehicle controller 6 output voltage signals, and the front axle ABS solenoid valve 3 and the rear axle ABS solenoid valve 4 are powered off. At this time, only the motor 7 electric feedback brake, the brake process is: the brake master cylinder module 1 outputs an analog voltage signal to the V2 pin of the vehicle controller 6, and the vehicle controller 6 outputs a request signal of corresponding size to the motor controller MCU module 5 according to the voltage signal size. The motor controller MCU module 5 controls the motor 7 to reverse, the motor 7 generates electricity while realizing vehicle braking, and then charges the power battery.

[0033] 2、When the brake pedal is pressed more than 30% of the stroke, the V3 and V4 pins of the vehicle controller 6 have no voltage output, and the front axle ABS solenoid valve 3 and the rear axle ABS solenoid valve 4 are powered on. To the front axle relay valve 4, control the 1 port of the front axle relay valve 8 to send the compressed air in the front axle air reservoir 12 to the front axle brake chamber 10 through the 2 port of the front axle relay valve 8, realize the front wheel brake, at the same time, the compressed air of the rear axle air reservoir 13 passes through the air inlet 11 port and the air outlet 21 port of the brake master cylinder module 1, the rear axle ABS solenoid valve 4, and reaches the 4 port of the rear axle relay valve 9, controls the 1 port of the rear axle relay valve 9 to send the compressed air in the rear axle air reservoir 13 to the rear axle brake chamber 11 through the 2 port of the rear axle relay valve 9, realizes the rear wheel brake. In this process, there is also electric feedback braking.

[0034] The brake master cylinder module in the embodiment can output analog voltage signals, and the air pressure output has small idle stroke; the air outlet 21 port and the air outlet 22 port of the brake master cylinder module 1 are directly connected with the corresponding relay valve 4 port through an ABS solenoid valve; the ABS solenoid valve is an electromagnetic valve used in the embodiment, and other normally-on electromagnetic valves can also be used in the patent range; for convenience of description, the battery capacity greater than or less than 90% is taken as the threshold range, and other pure electric vehicles can set the value to other numerical values, which are also in the patent range; whether the front axle ABS solenoid valve and the rear axle ABS solenoid valve are conductive is controlled by the vehicle controller. When the vehicle SOC is greater than 90%, the ABS solenoid valve is in the powered-off conductive state, and when the SOC value is not greater than 90%, the brake pedal opening needs to be judged. When the brake pedal is just pressed, the ABS solenoid valve is powered off when the brake pedal opening reaches 30%, and the ABS solenoid valve is powered on when the pedal opening is greater than 30%.

[0035] The above embodiment only expresses the specific implementation of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the patent range of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the protection scope of the present application.

Claims

1. A pure electric vehicle air pressure brake system, comprising a vehicle control unit, a brake master cylinder module, a BMS module and a MCU module connected with the vehicle control unit, the MCU module is connected with a motor, characterized in that, The application also comprises a gas cylinder and an electromagnetic valve connected with the whole vehicle controller, one end of the gas cylinder is connected with the control port of a relay valve through the brake master pump module and the electromagnetic valve, the gas source interface of the relay valve is connected with the other end of the gas cylinder, and the air outlet of the relay valve is connected with the brake air chamber of the wheel.

2. The all-electric vehicle air brake system of claim 1, wherein, The electromagnetic valve is an ABS electromagnetic valve.

3. The all-electric vehicle air brake system of claim 2, wherein, The ABS electromagnetic valve comprises a front axle ABS electromagnetic valve and a rear axle ABS electromagnetic valve, the gas cylinder comprises a front axle gas cylinder and a rear axle gas cylinder, the relay valve comprises a front axle relay valve and a rear axle relay valve, and the brake air chamber comprises a front axle brake air chamber and a rear axle brake air chamber; one end of the front axle gas cylinder is connected with the control port of the front axle relay valve through the brake master pump module and the front axle ABS electromagnetic valve, the gas source interface of the front axle relay valve is connected with the other end of the front axle gas cylinder, and the air outlet of the front axle relay valve is connected with the front axle brake air chamber of the wheel; one end of the rear axle gas cylinder is connected with the control port of the rear axle relay valve through the brake master pump module and the rear axle ABS electromagnetic valve, the gas source interface of the rear axle relay valve is connected with the other end of the rear axle gas cylinder, and the air outlet of the rear axle relay valve is connected with the rear axle brake air chamber of the wheel.

4. The all-electric vehicle air brake system of claim 1, wherein, The BMS module and the MCU module are connected with the whole vehicle controller through a CAN bus.

Images