A pneumatic integrated electronic parking system for commercial vehicles

Abstract

The present invention discloses a pneumatic integrated electronic parking system for commercial vehicles, belonging to the technical field of vehicle brake control, comprising a compressed air tank (10), a two-position two-way air control valve (2), a relay valve (4), a throttle valve (9), an electronic control unit (7), a pressure sensor (8), a spring brake air chamber (6), a muffler (5), a manual air inlet and outlet (11), a two-position two-way solenoid valve (1), and a two-position three-way solenoid valve (3), and having the characteristics of simple structure, good controllability and high safety.

Description

Technical Field

[0001] The invention relates to the technical field of vehicle brake control, in particular to a pneumatic integrated electronic parking system for commercial vehicles. Background Art

[0002] With the development of autonomous driving and intelligent braking technology, the shift from traditional manual parking to electronic parking has become an inevitable trend in the development of braking technology. In addition to the traditional handbrake function, the electronic parking system should also have functions such as hill start assist, dynamic braking, and anti-slip. Therefore, the electronic parking system also puts forward higher requirements on the function and performance of the parking control valve. Compared with the widespread application in passenger cars, due to the limitations of the function and performance of the parking control valve, the application of electronic parking in the field of commercial vehicles is still in its infancy, especially the electronic parking applied to the pneumatic brake system.

[0003] As for the electronic parking technology of the pneumatic brake system, the pneumatic control valve used in the industrial system is currently generally adopted, which can only realize part of the electronic parking function and has general environmental applicability. For example, the invention patent application (patent application number CN201710118935.3, published on June 13, 2017) uses three two-position two-way solenoid valves to realize electronic parking, which increases the control difficulty and component cost and reduces the reliability of the system; the invention patent (patent number CN201310025781.5, published on May 8, 2013) uses a pneumatic pilot two-position three-way solenoid valve to realize the function of EPB. Since the valve adopts dual electric control, it can realize the state holding function and improve the reliability. However, due to the harsh working environment of the vehicle, especially when the humidity is high and the temperature is low, the valve core adopts a sliding valve structure, which is easy to get stuck due to condensation in a low temperature environment, thereby reducing the reliability of the system; the patent (patent number CN201621419439.9, published on July 21, 2017) uses a two-position three-way and a two-position two-way valve combination. If the two-position two-way solenoid valve leaks during parking, it may cause a slipping accident. The invention patent application (patent application number CN201810473063.7, published on September 7, 2018) discloses a pneumatic electronic parking system, including an electronic control unit, a parking brake module and a trailer module that are independent of each other and can be connected to each other through a designed interface or external wires / pipes. However, the invention adopts a technical solution that is provided with three solenoid valves and one air-controlled valve in order to realize the vehicle braking and release functions. Not only is the structure complex, but the resulting failure nodes will increase exponentially, which will further increase the vehicle maintenance cost after subsequent batch installation, and the economy is not good. In addition, the invention requires the linkage operation of three solenoid valves and one air-controlled valve to realize service braking or parking, which may cause the braking time to be too long due to the different response times between the three solenoid valves, thereby increasing the risk of accidents.

[0004] Through the analysis of the existing pneumatic electronic parking technology, it is found that the following problems exist:

[0005] (1) When the industrial dual-electrically controlled two-position three-way solenoid valve is directly applied to the control of the pneumatic brake system, it is difficult to achieve high-speed charging and discharging due to the response lag problem, and it cannot meet the dynamic parking requirements;

[0006] (2) The plunger valve core is easily frozen due to condensation in a low temperature environment, causing the valve core to be stuck, the system to fail, and the environmental applicability to be poor;

[0007] (3) When the two-position two-way solenoid valve is suddenly powered off during driving, the system will find it difficult to maintain the current state, and sudden braking may cause an accident;

[0008] (4) When parking, if the solenoid valve leaks, pressure may accumulate and the vehicle may slip, thereby reducing the reliability and safety of the system. Summary of the invention

[0009] In view of the above problems, the present invention proposes a commercial vehicle air pressure integrated electronic parking system with simple structure, good controllability and high safety. The technical solution to realize the present invention is:

[0010] A pneumatic integrated electronic parking system for commercial vehicles comprises a compressed gas tank 10, a two-position two-way air control valve 2, a relay valve 4, a throttle valve 9, an electronic control unit 7, a pressure sensor 8, a spring brake air chamber 6, a muffler 5, a manual air inlet and outlet 11, a two-position two-way solenoid valve 1, and a two-position three-way solenoid valve 3. The output interface 1b of the two-position two-way solenoid valve 1 is connected to the control chamber input port 4d of the relay valve 4, and its output interface 1b is connected to the pneumatic control port of the two-position two-way air control valve 2; the output interface A of the two-position three-way solenoid valve 3 is connected to the control chamber input port 4d of the relay valve 4, its air supply port P is connected to the output interface 2b of the two-position two-way air control valve 2, and the exhaust port R is connected to the input port of the muffler 5; the two-position two-way solenoid valve 1, the two-position three-way solenoid valve 3 and the pressure sensor 8 are all connected to the electronic control unit 7, the two-position two-way solenoid valve 1 and the two-position three-way solenoid valve 3 are both normally closed solenoid valves, and the pressure sensor 8 is connected to the spring brake air chamber 6 to monitor the pressure of the spring brake air chamber 6 and feed it back to the system control unit.

[0011] Compared with the prior art, the main advantages of the present invention are:

[0012] 1) High safety: When driving, if the system suddenly loses power, the air-controlled solenoid valve can maintain the current state under air pressure control, avoiding sudden switching of the braking state and ensuring driving safety; when parking, if the two-position two-way solenoid valve leaks, the leaked compressed air will enter the exhaust port 4b of the relay valve through the throttle valve 9, and the vehicle will not slip due to pressure accumulation.

[0013] 2) Good controllability: The system uses two direct-acting high-speed switching valves, which can be used to accurately increase or decrease pressure and maintain pressure, thereby realizing advanced braking functions such as emergency dynamic parking and anti-lock braking. And because the high-speed switching valve is a cone valve structure, the system has better low-temperature applicability.

[0014] 3) With safety backup: It is designed with a manual operating mechanism. When the system is powered off and cannot be driven, the vehicle can be parked by operating the manual button, thus ensuring the safety of the vehicle and facilitating repair and maintenance.

[0015] 4) Good durability: Through the optimized design of the gas circuit, the solenoid valve is prevented from being energized for a long time during driving, which can reduce coil loss, save energy and extend the service life of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a structural diagram of the integrated electronic parking system of the present invention; Figure 2 A diagram showing the parking release state of the integrated electronic parking system of the present invention; Figure 3 A parking state diagram of the integrated electronic parking system of the present invention;

[0017] In the figure, 1- two-position two-way solenoid valve, 2- two-position two-way air control valve, 3- two-position three-way solenoid valve, 4- relay valve, 5- muffler, 6- spring brake air chamber, 7- electronic control unit (ECU), 8- pressure sensor, 9- throttle valve, 10- air tank, 11- manual exhaust port. DETAILED DESCRIPTION

[0018] The content of this application is described in detail below with reference to the accompanying drawings.

[0019] Figure 1The electronic parking system for commercial vehicles provided by the present invention is shown in the figure, which includes a compressed gas tank 10 for providing a compressed air source, whose gas source interface is connected to the input interface 1a of the two-position two-way solenoid valve 1, and is also connected to the input interface 2a of the two-position two-way air control valve 2 and the input interface 4a of the relay valve 4; the solenoid valve 1 is a two-position two-way normally closed solenoid valve, whose output interface is connected to the control chamber input port 4d of the relay valve 4, and at the same time, its output interface 1b is connected to the pneumatic control port of the two-position two-way air control valve 2; the output interface A of the two-position three-way solenoid valve 3 is connected to the control chamber input port 4d of the relay valve 4, its air supply port P is connected to the output interface 2b of the two-position two-way air control valve 2, and the exhaust port R is connected to the input port of the muffler 5; the interface 4c of the relay valve 4 is connected to the brake air chamber 6; the throttle valve 9 is respectively connected to the control port 4d and the output port 4c of the relay valve; 11 is a manual air inlet and outlet port. In the electrical part, the two-position two-way solenoid valve 1, the two-position three-way solenoid valve 3 and the pressure sensor 8 are all connected to the electronic control unit 7; the pressure sensor 8 monitors the pressure of the spring brake air chamber 6 and feeds it back to the system control unit, providing a basis for pressure detection and fault diagnosis of the brake control module; the ECU, as the system control unit, identifies different braking intentions and implements corresponding braking actions.

[0020] A two-position two-way solenoid valve and a two-position three-way solenoid valve are used to control the pilot chamber pressure of the relay valve. The pressure can be adjusted quickly under emergency conditions, and advanced functions such as dynamic braking and anti-lock braking can be realized. The two-position two-way air control valve is used to release the parking and maintain the state, which can avoid the sudden loss of control chamber pressure when the system is powered off and cause the driving state to switch suddenly, thereby improving the safety of the system. In this system, the two-position two-way solenoid valve will only be powered on when the parking action is released, and the two-position three-way solenoid valve needs to be powered on only when the parking action is taken, thereby avoiding the direct-acting solenoid valve from being powered on for a long time, which can effectively extend the life of the components. The pressure sensor is used to monitor the pressure of the brake air chamber to determine whether the solenoid valve is working normally, thereby realizing the solenoid valve fault diagnosis function.

[0021] Initially, the system is in Figure 1 In the state shown, the two-position two-way solenoid valve 1 and the two-position three-way solenoid valve 3 are not powered on, and the A port and the P port of the two-position three-way solenoid valve 3 are connected. Since there is no pressure in the control chamber of the relay valve 4 and the relay valve 4 is also in the exhaust state, there is no pressure in the spring brake air chamber and the system is in the parking state (such as Figure 1 as shown).

[0022] 1) Release parking When the electronic parking system receives the release parking command, the two-position two-way solenoid valve 1 is powered on and switched from the closed state to the open state. After the compressed air passes through the two-position two-way solenoid valve 1, the pressure in the control chamber of the relay valve 4 increases, and the main valve of the relay valve 4 opens. The compressed air enters from the interface 4a of the relay valve 4, and then enters the spring brake air chamber 6 through the interface 4c. At the same time, the pressure in the control chamber of the relay valve increases, causing the state of the two-position two-way air control valve 2 to change from the closed state to the open state. Thereafter, the two-position two-way solenoid valve 1 is powered off, and the two-position two-way air control valve 2 will continue to remain in the open state. The continuous input of compressed air keeps the main valve of the relay valve 4 in the open state. Under the action of the compressed air, the push rod of the spring brake air chamber 6 retracts, releasing the parking brake (such as Figure 2 ).

[0023] 2) Parking When the vehicle needs to enter the braking state from the driving state, the two-position three-way solenoid valve 3 is powered on for 200ms. At this time, the R port is connected to the A port, and the gas in the control chamber of the relay valve 4 will flow out through the R port of the two-position three-way solenoid valve 3, and finally released through the muffler 5, which will cause the pressure in the control chamber of the relay valve 4 to drop, so that the exhaust valve of the relay valve 4 opens, and the compressed gas in the spring brake air chamber 6 will flow out through the exhaust port 4b of the relay valve 4, and finally released through the muffler 5, so that the push rod of the spring brake air chamber 6 is pushed out under the action of the spring force to implement braking. (such as Figure 3 ) At this time, due to the decrease in the control chamber pressure of the relay valve 4, the two-position two-way air control valve 2 will also return to its initial state under the action of the spring force (such as Figure 1 ).

[0024] 3) During normal driving, since the control chamber of the relay valve 4 is always supplied with compressed air, the main valve of the relay valve 4 will remain open, and the push rod of the spring brake chamber 6 will remain in a retracted state. At this time, the two-position two-way solenoid valve 1 and the two-position three-way solenoid valve 3 do not need to be powered on. Therefore, when the electronic parking system fails to power on, the compressed gas in the spring brake chamber 6 will not be suddenly released, that is, the driving state of the vehicle will not be suddenly switched, and driving safety is effectively guaranteed.

[0025] 4) Anti-leakage and car slipping When the vehicle stops on a slope, if valve 1 leaks, compressed air will enter the control chamber of the relay valve through the air inlet, and the accumulation of compressed air will cause the relay valve to open, and the compressed gas will enter the spring brake air chamber through the main valve of the relay valve, so the vehicle will slip. However, for this system, the leaked gas will flow into the exhaust port 4b of the relay valve through the throttle valve 9, and finally be discharged into the atmosphere through the muffler, avoiding the pressure accumulation in the control chamber of the relay valve 4, preventing the problem of car slipping due to gas leakage, and improving the safety of the system.

[0026] 5) Dynamic parking In this system, both the two-position two-way solenoid valve 1 and the two-position three-way solenoid valve 3 use direct-acting high-speed switch valves, which can accurately control the brake pressure. When the vehicle encounters an emergency, such as service brake failure, the driver can turn on the electronic parking brake switch to trigger the dynamic parking function. The system can dynamically adjust the braking force to prevent wheel locking while ensuring a certain braking strength, thereby improving braking safety.

[0027] 6) Safety backup When the electronic parking system fails to operate normally due to power failure or other faults, the parking operation can be performed through the manual operation button. During driving, when parking operation is required, just turn on the manual operation button, the gas in the control chamber of the relay valve 4 will be discharged through the manual air inlet and outlet 11, the exhaust valve of the relay valve 4 will open, and the compressed gas in the spring brake air chamber 6 will flow out through the interface 4b of the relay valve 4, and finally released through the muffler 5, so that the push rod of the spring brake air chamber 6 is pushed out under the action of the spring force to implement braking.

[0028] During normal operation, the device can inflate or exhaust the system through the combined action of the valves, thereby parking or unparking the vehicle, and the application of air-controlled valves can avoid the system from being powered on for a long time, effectively improving the life of components and system reliability; when a power failure occurs, the system can maintain the current state to prevent the entire vehicle from suddenly braking due to system power failure; when parking, if the vehicle is parked on a slope, the system can effectively prevent pressure accumulation through the throttle valve to avoid rolling accidents; since the main circuit uses a high-speed switching valve, the system responds quickly and can meet the needs of rapid charging and deflating during emergency braking, avoid locking of the rear wheels, reduce the risk of drifting, and improve vehicle braking stability.

Claims

1. A pneumatic integrated electronic parking system for commercial vehicles, comprising a compressed gas tank (10), a two-position two-way gas control valve (2), a relay valve (4), a throttle valve (9), an electronic control unit (7), a pressure sensor (8), a spring brake air chamber (6), a muffler (5), and a manual air inlet and outlet (11), characterized in that: It also comprises a two-position two-way solenoid valve (1) and a two-position three-way solenoid valve (3); the output interface (1b) of the two-position two-way solenoid valve (1) is connected to the control chamber input port (4d) of the relay valve (4), and the output interface (1b) of the two-position two-way solenoid valve is connected to the pneumatic control port of the two-position two-way air control valve (2); the output interface (A) of the two-position three-way solenoid valve (3) is connected to the control chamber input port (4d) of the relay valve (4), the air supply port (P) is connected to the output interface (2b) of the two-position two-way air control valve (2), and the exhaust port (R) is connected to the input port of the muffler (5); the two-position two-way solenoid valve (1), the two-position three-way solenoid valve (3) and the pressure sensor (8) are respectively connected to the electronic control unit (7).

2. The pneumatic integrated electronic parking system for commercial vehicles according to claim 1, characterized in that: The two-position two-way solenoid valve (1) and the two-position three-way solenoid valve (3) are normally closed solenoid valves.

3. The pneumatic integrated electronic parking system for commercial vehicles according to claim 1 or 2, characterized in that: The pressure sensor (8) is connected to the spring brake air chamber (6).

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