Trailer fault diagnosis method and trailer brake air pressure detection system

Abstract

The invention discloses a trailer fault diagnosis method, which comprises the following steps that: step 1, the connection relationship between a traction main vehicle and a trailer is confirmed, a terminal acquires the sampled air pressure of an air storage tank, and whether the air pressure is lower than a set value is confirmed; 2, the terminal obtains a trailer monitoring signal and confirms the driving state of the traction main vehicle and the trailer. The invention further discloses a trailer brake air pressure detection system. According to the trailer air pressure detection system and the fault diagnosis method, starting from the braking principle of the trailer, air pressure monitoring is directly conducted on the parking braking air path and the traveling braking air path which are used for controlling braking of the trailer, the abnormity of the braking system can be effectively found in time, sufficient response time is provided for a user, and the braking efficiency of the trailer is improved. The occurrence of risks is greatly reduced, and the types of brake faults can be more accurately obtained by combining monitoring of air pressure with analysis of brake signals and GPS vehicle speed signals in the driving process, so that a user can make a response scheme in a targeted manner.

Description

Technical Field

[0001] The invention belongs to the technical field of trailer operation detection, and relates to a trailer fault diagnosis method and a trailer brake air pressure detection system. Background Art

[0002] A trailer is a vehicle towed by a car but without its own power drive device. It is a combination of a car (truck or tractor, forklift) and one or more trailers. It has no power itself, carries loads independently, and relies on other vehicles to tow it for travel.

[0003] According to the characteristics of the trailer, the trailer itself is equipped with a brake system. After the trailer is connected to the towing main vehicle, the brake system of the trailer is controlled by the towing main vehicle. Due to the high frequency of use of the trailer itself and the lack of timely maintenance, there are many cases where the brake system is still in use despite failures. If it is not taken seriously for a long time, it will cause major accidents, especially during driving.

[0004] The mainstream existing fault detection products for trailer brake systems are to detect tire temperature, tire pressure, brake disc temperature, etc. to confirm whether the brake system is faulty by checking whether the trailer is in a normal driving state. However, this method has a large lag in sensing faults. When tire temperature, tire pressure, and brake disc temperature are abnormal, it means that the brake system has been faulty for a long time and may be dangerous at any time. Trailers are often seen on highways, which do not support picking up the vehicle for inspection anytime and anywhere. Therefore, a detection system that can sense faults in a timely manner is urgently needed. Summary of the invention

[0005] In order to overcome the deficiencies of the prior art, the present invention provides a trailer fault diagnosis method and a trailer brake air pressure detection system.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A trailer fault diagnosis method comprises the following steps:

[0008] Step 1: Confirm the connection between the traction vehicle and the trailer, and the terminal obtains the sampled air pressure signal of the air storage tank to confirm whether the air pressure is lower than the set value;

[0009] Step 2: The terminal obtains the trailer monitoring signal to confirm the driving status of the towing vehicle and the trailer. The terminal obtains the brake signal and the sampled air tank pressure signal and the service brake air line pressure signal to confirm the braking status of the trailer.

[0010] Furthermore, in step 2, after confirming the driving status of the traction main vehicle and the trailer, when any continuous braking signal is generated and obtained by the terminal, the terminal controls the pressure detection device to perform multiple samplings with a set sampling period within the duration of the current braking signal and within the set time after the end of the current braking signal, and obtains the air pressure sampling information.

[0011] Furthermore, in step 2, confirming the braking status of the trailer includes: when the air pressure in the air tank is lower than the set value one, it is confirmed as brake fault one; when the service brake air circuit pressure is lower than the set value two or the rising rate is slower than the set rising rate within the time period of any continuous brake signal, it is confirmed as brake fault two; when the service brake air circuit pressure is higher than the set value three or the falling rate is slower than the set falling rate within the set period after the end of any continuous brake signal, it is confirmed as brake fault three.

[0012] Furthermore, it also includes a user end, when a brake failure is confirmed, the terminal controls the user end to display a fault alarm message.

[0013] Furthermore, when it is confirmed to be brake fault three, the fault alarm information includes the danger level, and the danger level calculation formula is:

[0014]

[0015] Among them, Risk 单 is the risk level of the brake drum of the single-chamber cylinder when a brake failure occurs for three times, n is the discrete sampling time sequence when a brake failure occurs for three times, k is the sampling data sequence number from 0 to n, V k is the GPS vehicle speed at the time sequence corresponding to the current sampling data sequence number, P 2k It is the instantaneous air pressure of the service brake air circuit at the timing corresponding to the current sampling data sequence number.

[0016] A trailer brake air pressure detection system, used to execute the above trailer fault diagnosis method, comprising:

[0017] A trailer gas tank air pressure detection device is provided on the trailer gas tank and is used to detect and generate a gas tank air pressure signal;

[0018] The service brake air circuit air pressure detection device is arranged in the trailer service brake air circuit and is used to detect and generate a service brake air circuit air pressure signal.

[0019] Furthermore, it also includes a terminal for obtaining the GPS speed signal and brake signal of the trailer. The trailer air tank air pressure detection device and the service brake air circuit air pressure detection device are both connected to the terminal, and the terminal obtains the air tank air pressure signal and the service brake air circuit air pressure signal respectively.

[0020] Furthermore, the trailer air tank air pressure detection device or the service brake air circuit air pressure detection device includes a shell, a pressure chip and a transmission harness, the pressure chip is arranged in the shell, the transmission harness is connected to the pressure chip and the terminal, and the shell is provided with a mounting portion for connecting to the service brake air circuit or the air tank.

[0021] In summary, the present invention is beneficial in that:

[0022] The trailer brake air pressure detection system and fault diagnosis method of the present invention start from the braking principle of the trailer, and directly monitor the air pressure of the two air circuits, the parking brake air circuit and the driving brake air circuit, which are used to control the trailer brakes. It can effectively and timely discover the abnormality of the brake system, so as to give the user sufficient response time and greatly reduce the occurrence of risks. In addition, the air pressure monitoring combined with the analysis of the brake signal and GPS speed signal during driving can more accurately obtain the type of brake fault, so that the user can make targeted response plans. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a flowchart of the fault diagnosis method of the present invention.

[0024] Figure 2 It is a wiring diagram of the parking brake air circuit and the service brake air circuit under different fault types in the fault diagnosis method of the present invention.

[0025] Figure 3 It is a structural schematic diagram of the air pressure detection device.

[0026] Figure 4 for Figure 3 Schematic diagram of the cross-section structure in.

[0027] Figure 5 This is a schematic diagram of the structure of the connecting flange of the air pressure detection device.

[0028] Figure 6 for Figure 5 Schematic diagram of the structure of the medium air pressure detection device connected to the air storage tank.

[0029] Markings in the figure: 1. Shell; 11. Cavity; 12. Mounting part; 13. Air duct; 2. Pressure chip; 3. Transmission harness; 4. Connecting flange; 41. Connecting part; 42. Through hole; 43. Drain valve connector; 44. Mounting hole; 5. Air tank; 51. Water level. DETAILED DESCRIPTION

[0030] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0031] It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and thus the drawings only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0032] All directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, horizontal, vertical...) are only used to explain the relative position relationship, movement status, etc. between the components in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0033] Due to installation errors and other reasons, the parallel relationship referred to in the embodiments of the present invention may actually be an approximately parallel relationship, and the vertical relationship may actually be an approximately vertical relationship.

[0034] The present invention provides a trailer brake air pressure detection system, which is used to detect the pressure in the brake air pipeline of the trailer brake system to monitor whether there is a fault in the trailer during driving, wherein the brake air pipeline of the trailer includes a driving brake air circuit and a parking brake air circuit, and the driving brake air circuit and the parking brake air circuit are both connected to a brake drum.

[0035] The brake drum adopts the brake drum structure commonly used in the prior art for trailer brake control, including a push plate push rod, a driving chamber and a parking chamber. The push plate push rod can be retracted and extended to brake the vehicle when extended and release the brake when retracted. A diaphragm and a return spring are arranged in the driving chamber. The diaphragm deforms when the air pressure in the chamber changes to promote the extension and retraction of the push plate push rod. A piston and an energy storage spring are arranged in the parking chamber. The air pressure in the parking chamber counteracts the energy storage spring to drive the piston to move. One end of the piston pushes the extension and retraction of the push plate push rod.

[0036] The air storage tank and the parking brake air circuit are connected to the parking chamber, and the air storage tank and the parking brake air circuit take in and out air into the parking chamber. When the trailer of the trailer is separated from the towing main vehicle, the parking chamber is disconnected from the parking air storage tank, and the air pressure in the parking chamber is insufficient to counteract the energy storage spring. The piston is pushed to one end of the stroke under the action of the energy storage spring, pushing and maintaining the extended state of the push plate push rod, thereby maintaining the parking brake on the trailer; when the towing main vehicle is connected to the trailer, the air storage tank is connected to the parking chamber, and air is taken into the parking chamber, so that the air pressure in the parking chamber reaches the set value. Under the set value, the piston compresses the energy storage spring under the push of the air pressure and is pushed to the other end of the stroke. The push plate push rod is not subject to the thrust of the piston and is maintained in a retracted state under the action of the return spring, thereby releasing the parking brake on the trailer.

[0037] The service brake air circuit is connected to the service cavity and the relay valve. The relay valve controls the air intake and exhaust of the service brake air circuit into the service cavity. When a service brake signal is generated, the relay valve and the service brake air circuit intake air into the service cavity, increasing the air pressure in the service cavity, causing the diaphragm to deform and push the push plate push rod to extend, thereby applying service brakes to the trailer. When the service brake signal ends, the relay valve controls the service brake air circuit and the service cavity to release pressure, and the push plate push rod and the diaphragm retract under the action of the return spring, thereby releasing the service brakes on the trailer.

[0038] The trailer brake system structure formed by the brake air pipeline, brake drum, air storage tank, etc. has been maturely applied in the prior art, and the present invention directly quotes the prior art for this part of the structure.

[0039] The obstruction of the brake system air pipeline is the main cause of trailer brake failure. Among them, the parking brake air circuit is blocked, resulting in insufficient parking chamber pressure causing drag brake, and the driving brake air circuit is blocked, resulting in a brake failure caused by obstruction of driving chamber pressure increase, or drag brake caused by obstruction of pressure relief. These are the most common types of failures with the highest risk factors.

[0040] In this embodiment, the trailer brake air pressure detection system includes a trailer air tank air pressure detection device and a service brake air circuit air pressure detection device, which are respectively arranged in the parking brake air circuit and the service brake air circuit, and are used to monitor the air pressure in the parking brake air circuit and the service brake air circuit respectively.

[0041] Among them, the above two air pressure detection devices adopt the same structure, referring to Figure 3 and Figure 4 , including a shell 1, a pressure chip 2 and a transmission harness 3. The shell 1 is a cylindrical structure. One end of the shell 1 in the axial direction is connected to a cavity 11. The pressure chip 2 is arranged in the cavity 11. One end of the transmission harness 3 is connected to the pressure chip 2, and the other end is led outward and connected to the terminal.

[0042] After the pressure chip 2 and the transmission harness 3 are arranged, the cavity 11 is further filled with potting glue for sealing.

[0043] A mounting portion 12 is provided at the other axial end of the housing 1, and the mounting portion 12 is used to form a connection with a valve core and other structures of a service brake air circuit or a parking brake air circuit. An air duct 13 is axially provided inside the mounting portion 12, and one end of the air duct 13 is connected to the inner wall of the cavity 11 and is directly opposite to the detection port of the pressure chip 2, so that the pressure chip 2 can quickly and sensitively detect the air pressure in the air circuit.

[0044] In some embodiments, limited by the installation position requirements of the parking brake air circuit, the pressure detection device is connected to the air storage tank 5. For details, refer to Figure 5 and Figure 6 The pressure detection device also includes a connecting flange 4, a connecting portion 41 is formed at one end of the connecting flange 4, and a thread can be provided on the outer periphery of the connecting portion 41 for connection with a threaded hole provided at the bottom of the gas storage tank 5. The outer periphery of the connecting flange 4 can be provided with a polygonal structure for convenient installation to the gas storage tank 5. A through hole 42 is provided in the connecting flange 4, and an opening is formed at one end of the through hole 42 at the end of the connecting portion 41. After the connecting portion 41 and the gas storage tank 5 are installed, the through hole 42 is connected to the inside of the gas storage tank 5.

[0045] A mounting hole 44 is provided on one side of the outer periphery of the connecting flange 4 for mounting the mounting portion 12 on the connecting flange 4. The mounting portion 12 is inserted and fixed in the mounting hole 44 so that the airway 13 is connected with the through hole 42. The air pressure in the air storage tank 5 is synchronously reflected to the pressure chip 2 through the through hole 42 and the airway 13, thereby realizing the detection of the air pressure.

[0046] In some embodiments, in order to balance the pressure used for detection, a water level 51 of a certain height is set at the bottom of the air storage tank 5, and the other end of the through hole 42 is connected to the other end of the connecting flange 4 to form a drain valve joint 43, so that the water in the air storage tank 5 can be filled into the through hole 42. Furthermore, when the outer shell 1 is in the mounting hole 44, the axis of the outer shell 1 is tilted upward relative to the horizontal plane to form a set angle, and the set angle is between a range of greater than 0 and less than 90, so that the airway 13 is in an inclined posture, and the water in the through hole 42 enters along the bottom opening of the airway 13, forming a water stop line in the airway 13, so that a certain air column remains in the airway 13, thereby preventing water from invading the pressure chip 2 while ensuring the accuracy of the air pressure detection value.

[0047] The detection system also includes a terminal, which is connected to the driving trailer control circuit and to two air pressure detection devices. The terminal obtains monitoring signals generated by the trailer, including but not limited to GPS speed signals, brake signals, and transient pressure signals of the two air pressure detection devices.

[0048] The present invention also provides a trailer fault diagnosis method, based on the above trailer brake air pressure detection system and air pressure detection device, comprising the following steps:

[0049] Step 1: Confirm the connection between the towing vehicle and the trailer, and the terminal obtains the sampled gas tank pressure signal to confirm whether the gas tank pressure is lower than the set value 1;

[0050] When the towing vehicle and the trailer are connected, the air tank of the towing vehicle will be connected to the parking brake pipeline to increase the air pressure in the parking chamber. In this embodiment, the setting value is preferably 4.0 bar.

[0051] Step 2: The terminal obtains the trailer monitoring signal, confirms the driving status of the towing vehicle and the trailer, and confirms the braking status of the trailer through the obtained brake signal and the sampled air pressure signal of the air storage tank and the air pressure signal of the service brake air path;

[0052] After confirming the driving status of the towing vehicle and the trailer, when any continuous brake signal is generated and acquired by the terminal, the terminal controls the pressure detection device to perform multiple samplings at a set sampling period within the duration of the current brake signal and the set time after the current brake signal ends, and obtains the information of the air pressure sampling;

[0053] Step 3: When the air pressure of the air tank is lower than the set value 1, it is confirmed as brake fault 1; when the air pressure of the service brake air circuit is lower than the set value 2 or the rising rate is lower than the set rising rate within the time period of any continuous brake signal, it is confirmed as brake fault 2; when the air pressure of the service brake air circuit is higher than the set value 3 or the falling rate is lower than the set falling rate within the set period after any continuous brake signal ends, it is confirmed as brake fault 3;

[0054] When the trailer is running without any fault, the air pressure in the air tank should be kept above the set value 1 to avoid the generation of parking brake force; when any brake signal occurs, the air pressure in the service brake air circuit should quickly rise to above the set value 2 to generate braking force in time, and when the brake signal ends, the air pressure in the service brake air circuit should quickly drop to below the set value 3 to release the braking force in time;

[0055] When the air pressure in the air tank is lower than the set value, it means that the parking brake air path is blocked, the air pressure in the parking chamber is too low, and the energy storage spring and piston push the push rod out, resulting in a certain braking force on the trailer, causing drag brakes during driving;

[0056] When the air pressure of the service brake air circuit is lower than the set value 2 or the rising rate is lower than the set rising rate, it means that the air intake of the service brake air circuit into the service cavity is blocked, the air pressure in the service cavity is insufficient, the push plate push rod is not extended to the right position, the braking force generated by the trailer is weak or ineffective, and the braking is mainly borne by the towing main vehicle, resulting in the risk of high temperature of the drive wheel;

[0057] When the air pressure of the service brake air circuit is higher than the set value three or the decreasing rate is slower than the set decreasing rate, it means that the pressure relief of the service brake air circuit is blocked, the pressure relief in the service cavity is blocked, the push plate push rod cannot retract into place, and after releasing the brake, the trailer still has braking force, causing long-term dragging brake;

[0058] Step 4: When it is confirmed to be a brake fault, the terminal controls the user end to display a fault alarm message;

[0059] Step 4.1: When the brake fault is confirmed to be three, the terminal obtains the monitoring signal and calculates the risk level, where the risk level calculation formula is:

[0060]

[0061] Among them, Risk 单 is the risk level of the brake drum of the single-chamber cylinder when a brake failure occurs for three times, n is the discrete sampling time sequence when a brake failure occurs for three times, k is the sampling data sequence number from 0 to n, V k is the GPS vehicle speed at the time sequence corresponding to the current sampling data sequence number, P 2k It is the instantaneous air pressure of the service brake air circuit at the time sequence corresponding to the current sampling data sequence number;

[0062] The terminal displays the degree of danger to the user, and a limit value can be set in advance. When the degree of danger is lower than or higher than the limit value, a next site maintenance suggestion or an emergency stop suggestion is generated to the user.

[0063] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

Claims

1. A trailer fault diagnosis method, characterized in that: The following steps are involved: Step 1: Confirm the connection between the traction vehicle and the trailer, and the terminal obtains the sampled air pressure signal of the air storage tank to confirm whether the air pressure is lower than the set value; Step 2: The terminal obtains the trailer monitoring signal to confirm the driving status of the towing vehicle and the trailer. The terminal obtains the brake signal and the sampled air tank pressure signal and the service brake air line pressure signal to confirm the braking status of the trailer.

2. A trailer fault diagnosis method according to claim 1, characterized in that: In step 2, after confirming the driving status of the traction vehicle and the trailer, when any continuous braking signal is generated and obtained by the terminal, the terminal controls the pressure detection device to perform multiple samplings with a set sampling period within the duration of the current braking signal and within the set time after the end of the current braking signal, and obtains the air pressure sampling information.

3. A trailer fault diagnosis method according to claim 1 or 2, characterized in that: In step 2, confirming the braking status of the trailer includes: when the air pressure in the air tank is lower than the set value one, it is confirmed as brake fault one; when the air pressure in the service brake air circuit is lower than the set value two or the rising rate is lower than the set rising rate within the time period of any continuous brake signal, it is confirmed as brake fault two; when the air pressure in the service brake air circuit is higher than the set value three or the falling rate is lower than the set falling rate within the set period after the end of any continuous brake signal, it is confirmed as brake fault three.

4. A trailer fault diagnosis method according to claim 3, characterized in that: It also includes a user end. When a brake failure is confirmed, the terminal controls the user end to display a fault alarm message.

5. A trailer fault diagnosis method according to claim 4, characterized in that: When the brake fault is confirmed as level 3, the fault alarm information includes the degree of danger, and the formula for calculating the degree of danger is: Among them, Risk 单 is the risk level of the brake drum of the single-chamber cylinder when a brake failure occurs for three times, n is the discrete sampling time sequence when a brake failure occurs for three times, k is the sampling data sequence number from 0 to n, V k is the GPS vehicle speed at the time sequence corresponding to the current sampling data sequence number, P 2k It is the instantaneous air pressure of the service brake air circuit at the timing corresponding to the current sampling data sequence number.

6. A trailer brake air pressure detection system, used to execute the trailer fault diagnosis method according to any one of claims 1 to 5, characterized in that: include: A trailer gas tank air pressure detection device is provided on the trailer gas tank and is used to detect and generate a gas tank air pressure signal; The service brake air circuit air pressure detection device is arranged in the trailer service brake air circuit and is used to detect and generate a service brake air circuit air pressure signal.

7. A trailer brake air pressure detection system according to claim 6, characterized in that: It also includes a terminal for obtaining the GPS speed signal and brake signal of the trailer. The trailer air tank pressure detection device and the service brake air circuit pressure detection device are both connected to the terminal, and the terminal obtains the air tank pressure signal and the service brake air circuit pressure signal respectively.

8. A trailer brake air pressure detection system according to claim 6, characterized in that: The trailer air tank air pressure detection device or the service brake air circuit air pressure detection device includes a shell, a pressure chip and a transmission harness. The pressure chip is arranged in the shell. The transmission harness is connected to the pressure chip and the terminal. The shell is provided with a mounting portion for connecting to the service brake air circuit or the air tank.

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