A rear-mounted air brake system for a commercial vehicle

Abstract

This invention discloses a rear-mounted pneumatic braking system for commercial vehicles, comprising: an intake port of an intake / exhaust control assembly connected to the outlet of a spare air reservoir of the commercial vehicle, and an outlet connected to the intake port of a quick-release valve; a first outlet of the quick-release valve connected to the rear axle brake chamber of the commercial vehicle, and a second outlet of the quick-release valve connected to the front axle brake chamber of the commercial vehicle; the intake / exhaust control assembly includes a brake master valve and an integrated intake / exhaust valve; the intake port of the brake master valve is connected to the outlet of the spare air reservoir of the commercial vehicle, and the outlet is connected to the intake port of the integrated intake / exhaust valve; the outlet of the integrated intake / exhaust valve is connected to the intake port of the quick-release valve; a pneumatic controller is used to control the intake / exhaust control assembly to open when intervention in the vehicle's braking system is required, allowing gas from the spare air reservoir to enter the rear axle brake chamber and the front axle brake chamber through the outlet of the intake / exhaust control assembly. This invention can improve the reliability of the braking system and enhance the safety of commercial vehicles.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of commercial vehicle braking, in particular to a commercial vehicle rear-mounted air path braking system. BACKGROUND

[0002] The value of ADAS (Advanced Driver Assistance System) to the safety of commercial vehicles is recognized by traffic supervision departments, and the advanced emergency braking (AEB) function of commercial vehicles has been implemented since May 1, 2021 for trucks with a total mass of more than 12 tons and a maximum vehicle speed of more than 90 km / h, requiring the mandatory installation of AEB function. When a vehicle is about to collide, the AEB system avoids or mitigates the collision through warning and braking. However, the existing AEB air path braking system has poor reliability and is prone to safety problems. SUMMARY

[0003] The present application provides a commercial vehicle rear-mounted air path braking system to improve the reliability of the commercial vehicle rear-mounted braking system and improve the safety of the commercial vehicle.

[0004] According to an aspect of the present application, a commercial vehicle rear-mounted air path braking system is provided, comprising:

[0005] an air inlet and exhaust control assembly, a quick release valve and an air pressure controller;

[0006] The air inlet of the air inlet and exhaust control assembly is connected with the outlet of the spare air cylinder of the commercial vehicle, and the air outlet is connected with the air inlet of the quick release valve; the first air outlet of the quick release valve is connected with the rear axle brake chamber of the commercial vehicle, and the second air outlet of the quick release valve is connected with the front axle brake chamber of the commercial vehicle;

[0007] The air inlet and exhaust control assembly comprises a brake main valve and an air inlet and exhaust integrated valve; the air inlet of the brake main valve is connected with the outlet of the spare air cylinder of the commercial vehicle, and the air outlet is connected with the air inlet of the air inlet and exhaust integrated valve; the air outlet of the air inlet and exhaust integrated valve is connected with the air inlet of the quick release valve;

[0008] When it is detected that the vehicle braking system needs to be intervened, the air pressure controller controls the air inlet and exhaust control assembly to open, so that the gas in the spare air cylinder enters the rear axle brake chamber and the front axle brake chamber through the air outlet of the air inlet and exhaust control assembly.

[0009] Optionally, the system further comprises:

[0010] a gas source air pressure sensor and a control air path air pressure sensor;

[0011] The gas source air pressure sensor is used to detect the gas supply pressure of the spare air cylinder of the commercial vehicle;

[0012] The control gas path air pressure sensor is configured to detect the air pressure between the fast release valve and the front axle brake chamber and / or the rear axle brake chamber.

[0013] The air pressure controller is further configured to obtain the supply air pressure detected by the air source air pressure sensor and the control gas path air pressure detected by the control gas path air pressure sensor.

[0014] Optionally, the system further comprises:

[0015] a pressure limiting valve, a first double-pass one-way valve, and a second double-pass one-way valve.

[0016] The two air inlets of the first double-pass one-way valve are connected to the first air outlet of the fast release valve and the rear axle air reservoir of the commercial vehicle, respectively, and the air outlet is connected to the rear axle brake chamber; the two air inlets of the second double-pass one-way valve are connected to the second air outlet of the fast release valve and the front axle air reservoir of the commercial vehicle, respectively, and the air outlet is connected to the front axle brake chamber.

[0017] The pressure limiting valve is arranged on the air path between the air inlets of the second double-pass one-way valve and the fast release valve.

[0018] Optionally, the air outlet of the first double-pass one-way valve is further connected to a trailer brake chamber.

[0019] Optionally, the air pressure controller is configured to:

[0020] When it is detected that the vehicle brake system needs to be intervened, the target air pressure of the control gas path is determined, and the standby air reservoir supply end temperature, the current air temperature in the control gas path, the current supply air pressure of the standby air reservoir detected by the air source air pressure sensor, and the current control gas path air pressure detected by the control gas path air pressure sensor are obtained.

[0021] The required air mass that needs to enter the control gas path is determined according to the control gas path volume, the current air temperature in the control gas path, the current control gas path air pressure, and the target air pressure, and the energization duration of the preset air inlet valve of the air inlet and exhaust control assembly is calculated according to the standby air reservoir supply end temperature, the current supply air pressure, the current control gas path air pressure, the required air mass, and the mass flow characteristics of the air inlet valve.

[0022] The preset air inlet valve is energized according to the energization duration, so that the standby air reservoir supplies air to the control gas path, and the control gas path air pressure reaches the target air pressure.

[0023] When the brake main valve and the air inlet and exhaust integrated valve are normally working, the brake main valve is in a normally open state, the preset air inlet valve is the air inlet valve of the air inlet and exhaust integrated valve, and when the air inlet and exhaust integrated valve fails, the preset air inlet valve is the brake main valve.

[0024] Optionally, the gas pressure controller is configured to determine the required intake gas mass required to be input into the control gas path according to a difference between the target gas pressure and a current control gas path gas pressure, a current gas temperature in the control gas path, and a control gas path volume.

[0025] Optionally, the gas pressure controller is configured to:

[0026] determine the intake gas mass input into the control gas path after each opening step of the preset intake valve, a change in the gas pressure in the control gas path, and a change in the gas temperature in the control gas path according to the initial reserve gas cylinder supply gas pressure of each opening step of the preset intake valve, the initial control gas path gas pressure, the initial control gas path gas temperature, the reserve gas cylinder supply end temperature, and a mass flow characteristic of the preset intake valve;

[0027] determine the gas pressure in the control gas path after each opening step, the reserve gas cylinder supply gas pressure, and the control gas path gas temperature according to the change in the gas pressure in the control gas path and the change in the gas temperature in the control gas path;

[0028] take the gas pressure in the control gas path after one opening step, the reserve gas cylinder supply gas pressure, and the control gas path gas temperature as the initial reserve gas cylinder supply gas pressure, the initial control gas path gas pressure, and the initial control gas path gas temperature of the next opening step to calculate the intake gas mass input into the control gas path after the next opening step, the change in the gas pressure in the control gas path, and the change in the gas temperature in the control gas path;

[0029] accumulate the intake gas masses of multiple opening steps to obtain a total intake gas mass of all opening steps, and determine the time of all opening steps when the total intake gas mass is greater than or equal to the target intake mass as the power-on duration.

[0030] Optionally, the gas pressure controller is configured to:

[0031] determine the gas mass input into the control gas path after one opening step according to the initial reserve gas cylinder supply gas pressure of each opening step of the preset intake valve, the initial control gas path gas pressure, the reserve gas cylinder supply end temperature, and a mass flow characteristic calculation formula;

[0032] The mass flow characteristic calculation formula is:

[0033]

[0034] wherein, dm is the gas mass input into the control gas path after the i-th opening step, A e is an effective cross-sectional area of the preset intake valve; P1 is the initial reserve gas cylinder supply gas pressure of the i-th opening step; P2 is the initial control gas path gas pressure of the i-th opening step; T1 is the reserve gas cylinder supply end temperature; K G is a sonic flow flow coefficient;

[0035] The gas pressure variation quantity in the control loop after one opening step is calculated according to the first gas polytropic process formula, the gas temperature variation quantity in the control loop after one opening step is calculated according to the second gas polytropic process, and the absolute temperature of the gas in the control loop is obtained after integration and accumulation:

[0036] The first gas polytropic process formula is as follows:

[0037] The second gas polytropic process formula is as follows: Wherein, n is a polytropic index, dp is the gas pressure variation quantity in the control loop after the i-th opening step, dt is the power-on duration corresponding to one opening step, P is the initial control loop gas pressure of the i-th opening step, V is the control loop volume, R is the gas constant of air, T is the initial gas temperature in the control loop of the i-th opening step, dT is the gas temperature variation quantity in the control loop after the i-th opening step, and i is an integer greater than or equal to 1.

[0038] Optionally, the gas pressure controller is specifically configured to:

[0039] The final power-on duration is determined according to the power-on duration and the preset intake valve stable duration;

[0040] The preset intake valve is powered on according to the final power-on duration;

[0041] When the cumulative power-on time of the preset intake valve is equal to the final power-on duration, the actual gas pressure value in the control loop is obtained, and the difference between the target gas pressure and the actual gas pressure value in the control loop is calculated;

[0042] Whether to continue to power on the preset intake valve is determined according to the comparison result of the difference and the preset threshold range.

[0043] Optionally, the gas pressure controller is specifically configured to:

[0044] When the difference is greater than a first preset threshold value, the power-on extension duration of the preset intake valve is determined according to the difference, and the preset intake valve is powered on according to the power-on extension duration; wherein the first preset threshold value is a positive value;

[0045] When the difference is less than a second preset threshold value, the power-on duration of a preset exhaust valve of the intake and exhaust control assembly is determined according to the difference, and part of the gas in the control loop is discharged into the air by the preset exhaust valve according to the power-on duration of the preset exhaust valve; wherein the second preset threshold value is a negative value;

[0046] When the difference is within a preset range, the preset intake valve is stopped from being powered on;

[0047] The preset exhaust valve is the exhaust valve of the intake and exhaust integrated valve when the brake main valve and the intake and exhaust integrated valve are normally working, and the preset exhaust valve is the brake main valve when the intake and exhaust integrated valve is faulty.

[0048] The commercial vehicle rear-mounted air path brake system provided by the embodiment is provided with two valve bodies, i.e., a brake main valve and an intake and exhaust integrated valve, so that even if the intake and exhaust integrated valve fails to have the ability of air pressure regulation, the rear axle brake chamber and the front axle brake chamber can be supplied with air by controlling the opening and closing of the brake main valve, and air pressure braking is realized, and therefore, the commercial vehicle rear-mounted brake system provided by the embodiment has high reliability and can improve the safety of the commercial vehicle.

[0049] It should be understood that the content described in this part is not intended to identify key or important features of the embodiments of the present application, nor is it used to limit the scope of the present application. Other features of the present application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0051] Figure 1 is a schematic diagram of a commercial vehicle rear-mounted air path brake system provided by an embodiment of the present application;

[0052] Figure 2 is a schematic diagram of another commercial vehicle rear-mounted air path brake system provided by an embodiment of the present application;

[0053] Figure 3 is a working flowchart of an air pressure controller provided by an embodiment of the present application. DETAILED DESCRIPTION

[0054] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings of the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should be within the scope of protection of the present application.

[0055] It should be noted that the terms "first", "second", and the like in the description and in the claims of the present application and above-described accompanying drawings are intended to distinguish similar objects and not necessarily describe a particular sequential or chronological order. It should be understood that the data thus used can be interchanged, where appropriate, so that the embodiments of the application described herein can be implemented in orders other than those illustrated or described herein. In addition, the terms "comprise" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product, or apparatus including a list of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to such processes, methods, products, or apparatuses.

[0056] The embodiment of the present application provides a rear-mounted air path brake system of a commercial vehicle, Figure 1 is a schematic diagram of a rear-mounted air path brake system of a commercial vehicle provided by the embodiment of the present application, referring to Figure 1 The system comprises:

[0057] The intake and exhaust control assembly 10, the quick release valve 20 and the air pressure controller 30;

[0058] The air inlet of the intake and exhaust control assembly 10 is connected with the outlet of the standby air reservoir 40 of the commercial vehicle, and the air outlet is connected with the air inlet of the quick release valve 20; the first air outlet of the quick release valve 20 is connected with the rear axle brake chamber 50 of the commercial vehicle, and the second air outlet of the quick release valve 20 is connected with the front axle brake chamber 60 of the commercial vehicle;

[0059] The intake and exhaust control assembly 10 comprises a brake main valve 11 and an intake and exhaust integrated valve 12; the air inlet of the brake main valve 11 is connected with the outlet of the standby air reservoir 40 of the commercial vehicle, and the air outlet is connected with the air inlet of the intake and exhaust integrated valve 12; the air outlet of the intake and exhaust integrated valve 12 is connected with the air inlet of the quick release valve 20;

[0060] The air pressure controller 30 is used for detecting that the whole vehicle brake system needs to be intervened, controlling the intake and exhaust control assembly 10 to be opened, and enabling the gas in the standby air reservoir 40 to enter the rear axle brake chamber 50 and the front axle brake chamber 60 through the air outlet of the intake and exhaust control assembly 10.

[0061] The main brake valve 11 is connected to the spare air reservoir 40 equipped in the commercial vehicle. The main brake valve 11 is a normally closed valve. When closed, the valve's outlet is open to the atmosphere. When open, the gas in the spare air reservoir 40 can enter the pipeline connected to the outlet. The integrated intake and exhaust valve 12 is a three-position three-way valve. The integrated intake and exhaust valve 12 includes an intake valve and an exhaust valve. When both the intake valve and the exhaust valve are closed, the intake port and the outlet of the integrated intake and exhaust valve 12 are open. When the intake valve is open and the exhaust valve is closed, the outlet of the integrated intake and exhaust valve 12 is not open to the intake port or the atmosphere, thereby maintaining the pressure in the outlet pipeline. When both the intake valve and the exhaust valve are open, the outlet of the integrated intake and exhaust valve 12 is open to the atmosphere, realizing exhaust.

[0062] Specifically, when the brake master valve 11 and the integrated intake / exhaust valve 12 are working normally, the brake master valve 11 can be set to the normally open state. The air pressure controller 30 controls the opening and closing of the integrated intake / exhaust valve to open and close the intake / exhaust control component 10, thereby enabling the gas in the spare air reservoir 40 to enter the rear axle brake chamber 50 and the front axle brake chamber 60 through the outlet of the intake / exhaust control component 10 to achieve braking. When the integrated intake / exhaust valve 12 malfunctions, such as a constant exhaust or constant intake failure, the air pressure controller 30 controls the opening and closing of the brake master valve 11 to open and close the intake / exhaust control component 10.

[0063] The quick-release valve 20 is connected to the outlet of the integrated intake and exhaust valve 12, serving to quickly exhaust air. When the air pressure at the inlet of the quick-release valve 20 is higher than the diaphragm opening pressure, the diaphragm is opened, and gas enters the air pressure control circuits of the rear axle brake chamber 50 and the front axle brake chamber 60. When the air pressure at the inlet of the quick-release valve 20 is lower than the threshold air pressure, the diaphragm closes, and the gas in the air pressure control circuits of the rear axle brake chamber 50 and the front axle brake chamber 60 is quickly discharged into the atmosphere. The air pressure control circuits of the rear axle brake chamber 50 and the front axle brake chamber 60 are the air supply circuits between the integrated intake and exhaust valve 12 and the rear axle brake chamber 50 and the front axle brake chamber 60.

[0064] The commercial vehicle aftermarket air braking system provided in this embodiment has two valve bodies: a brake master valve and an integrated intake and exhaust valve. Even if the integrated intake and exhaust valve fails and loses its ability to regulate air pressure, air can still be supplied to the rear axle brake chamber and the front axle brake chamber by controlling the opening and closing of the brake master valve to achieve air pressure braking. Therefore, the commercial vehicle aftermarket braking system provided in this embodiment has high reliability and can improve the safety of commercial vehicles.

[0065] Optional, continue to refer to Figure 1 The system also includes:

[0066] Air source pressure sensor 70 and control air circuit pressure sensor 80;

[0067] The air source pressure sensor 70 is used to detect the air supply pressure of the spare air tank 40 in commercial vehicles;

[0068] The control air pressure sensor 80 is used to detect the control air pressure between the quick-release valve 20 and the front axle brake chamber 60 and / or the rear axle brake chamber 50.

[0069] The air pressure controller 30 is also used to acquire the supply air pressure measured by the air source air pressure sensor 70 and the control air pressure measured by the control air path air pressure sensor 80.

[0070] Specifically, the air source pressure sensor 70 is installed in the air path between the spare air storage tank 40 and the intake / exhaust control assembly 10. The air pressure controller 30 receives the supply air pressure measured by the air source pressure sensor 70 and the control air path pressure measured by the control air path pressure sensor 80. Based on the actual supply air pressure and the actual control air path pressure, it can control the brake master valve 11 and the integrated intake / exhaust valve 12, thereby enabling more precise air supply to the front axle brake chamber 60 and the rear axle brake chamber 50, achieving precise control of the control air path pressure and better braking performance.

[0071] In addition, the control air pressure sensor 80 can be installed only in the control air line between the front axle brake chamber 60 and the quick release valve 20, or only in the control air line between the rear axle brake chamber 50 and the quick release valve 20, or both in the control air lines between the front axle brake chamber 60 and the rear axle brake chamber 50 and the quick release valve 20. The specific installation method is not specifically limited in this embodiment.

[0072] Figure 2 This is a schematic diagram of another aftermarket air-circuit braking system for commercial vehicles provided in an embodiment of the present invention. Optional, see reference. Figure 2 The system also includes:

[0073] Pressure relief valve 90, first double-way check valve 100, and second double-way check valve 110:

[0074] The two air inlets of the first double-way one-way valve 100 are respectively connected to the first air outlet of the quick-release valve 20 and the rear axle air tank 120 of the commercial vehicle, and the air outlet is connected to the rear axle brake chamber; the two air inlets of the second double-way one-way valve 110 are respectively connected to the second air outlet of the quick-release valve 20 and the front axle air tank 130 of the commercial vehicle, and the air outlet is connected to the front axle brake chamber.

[0075] The pressure relief valve 90 is located in the air path between the inlet quick-release valve 20 of the second double-way check valve 110.

[0076] The front axle brake chambers include a left front brake chamber 61 and a right front brake chamber 62. The outlet of the second double-way check valve 110 is connected to the left front brake chamber 61 and the right front brake chamber 62 respectively via relay valves. The rear axle brake chambers include a left rear brake chamber 51 and a right rear brake chamber 52. The outlet of the first double-way check valve 100 is connected to the left rear brake chamber 51 and the right rear brake chamber 52 via another relay valve. One inlet of the first double-way check valve 100 is connected to the rear axle air reservoir 120 via a foot valve 140, and one inlet of the second double-way check valve 110 is connected to the front axle air reservoir 130 via a foot valve 140.

[0077] Specifically, when the air pressure at the outlet of the quick-release valve 20 increases, due to the function of the pressure limiting valve 90, the outlet of the pressure limiting valve 90 will only start to build pressure when the air pressure at the inlet of the pressure limiting valve 90 is higher than the pressure limiting threshold. Therefore, by placing the pressure limiting valve 90, the pressure building time of the front axle brake chamber is later than that of the rear axle brake chamber, ensuring driving safety during braking intervention. During exhaust, the front axle brake chamber and the rear axle brake chamber exhaust simultaneously.

[0078] The first dual-way check valve 100 and the second dual-way check valve 110 balance the air pressure from the foot valve 140 and the air pressure from the braking intervention. When the air pressure controlled by the foot valve 140 is higher than the air pressure from the air pressure controller 30 for braking intervention, the first dual-way check valve 100 and the second dual-way check valve 110 output the air pressure controlled by the foot valve 140; conversely, they output the air pressure from the braking intervention. The purpose of placing the dual-way check valves is to ensure that when the driver presses the brake pedal deeply and takes control of the vehicle, the braking force of the entire vehicle is controlled by the driver.

[0079] Optionally, the outlet of the first dual-way one-way valve 100 is also connected to the trailer brake chamber. By placing a pressure relief valve 90 in the front axle control air circuit of the system, the air intake of the front axle is physically ensured to be later than that of the rear axle and the trailer, which can avoid the trailer lurching phenomenon when braking intervention is performed, thus avoiding serious safety problems. The exhaust of the front axle is synchronized with the exhaust of the rear axle and the trailer.

[0080] Optionally, the air pressure controller 30 is used for:

[0081] When it is detected that intervention in the vehicle braking system is required, the target air pressure of the control air circuit is determined, and the temperature of the backup air reservoir supply end, the current gas temperature in the control air circuit, the current air supply pressure of the backup air reservoir 30 measured by the air source pressure sensor 70, and the current control air circuit pressure measured by the control air circuit pressure sensor 80 are obtained.

[0082] The required intake air mass to enter the control air path is determined based on the control air path volume, the current gas temperature in the control air path, the current control air path pressure, and the target gas pressure. The energizing time of the preset intake valve of the intake and exhaust control component 10 is calculated based on the temperature of the backup gas storage tank supply end, the current gas temperature in the control air path, the current supply gas pressure, the current control air path pressure, the required intake air mass, and the mass flow characteristics of the preset intake valve.

[0083] The preset air intake valve is energized according to the energizing duration, so that the standby air storage tank 30 supplies air to the control air circuit, so that the air pressure in the control air circuit reaches the target air pressure.

[0084] When the brake main valve 11 and the integrated intake and exhaust valve 12 are working normally, the brake main valve 11 is in the normally open state, and the preset intake valve is the intake valve of the integrated intake and exhaust valve 12. When the integrated intake and exhaust valve 12 fails, the preset intake valve is the brake main valve 11.

[0085] The temperature at the supply end of the backup air reservoir is the gas temperature inside the backup air reservoir 30, and the current gas temperature in the control air path is the gas temperature in the air path between the intake / exhaust control component 10 and the brake chamber. The temperature at the supply end of the backup air reservoir and the current gas temperature in the control air path can be considered to be the same as the atmospheric temperature. A temperature sensor can be installed inside the commercial vehicle, and the temperature at the supply end of the backup air reservoir and the current gas temperature in the control air path can be determined by reading the atmospheric temperature measured by this sensor. The volume of the control air path is the sum of the volumes of the air paths between the intake / exhaust control component 10 and each brake chamber. Optionally, the air pressure controller 30 determines the required intake air mass to enter the control air path based on the control air path volume, the current gas temperature in the control air path, the current control air path pressure, and the target air pressure. Alternatively, the air pressure controller 30 can determine the required intake air mass to enter the control air path based on the difference between the target air pressure and the current control air path pressure, the current gas temperature in the control air path, and the control air path volume.

[0086] Specifically, the mass of gas required to enter the control gas path can be calculated using the ideal gas state equation, which is: Gas pressure in the gas path * Gas ​​path volume = Gas mass in the gas path * Gas ​​constant of air * Gas ​​temperature, where the gas temperature is in Kelvin. Based on the difference between the target gas pressure and the current control gas path pressure, combined with other ideal state equations, the required intake gas mass can be calculated.

[0087] This embodiment combines the current gas temperature, current control air pressure, and target air pressure in the control air circuit at the current moment to determine the required intake air mass, resulting in a more accurate determination of the required intake air mass. Furthermore, it calculates the preset energizing duration of the intake valve in the intake and exhaust control component based on the temperature at the backup air reservoir supply end, the current supply air pressure, the current control air pressure, the required intake air mass, and the mass flow characteristics of the intake valve, making the determined energizing duration even more accurate. Precise air pressure control can be achieved under different air source pressures, different ambient temperatures, and different altitudes, ensuring consistent application of braking force throughout the vehicle and preventing serious safety issues.

[0088] Optionally, the power-on duration can be determined by the air pressure controller in the following ways:

[0089] Based on the initial standby air tank supply pressure, initial control air circuit pressure, initial control air circuit temperature, standby air tank supply end temperature, and the mass flow characteristics of the preset air intake valve, the intake mass, gas pressure change, and gas temperature change of the control air circuit are calculated after each opening step of the preset air intake valve.

[0090] The gas pressure in the control gas circuit, the gas supply pressure of the backup gas cylinder, and the gas temperature in the control gas circuit are determined based on the gas pressure change and the gas temperature change in the control gas circuit after each opening step.

[0091] The gas pressure in the control gas path after one opening step, the gas pressure supplied by the backup gas cylinder, and the gas temperature in the control gas path are used as the initial backup gas cylinder supply pressure, initial control gas path pressure, and initial control gas path temperature for the next opening step. After calculating the next opening step, the intake gas mass, gas pressure change, and gas temperature change of the control gas path are input.

[0092] The intake mass of multiple opening steps is accumulated to obtain the total intake mass of all opening steps. The time of all opening steps when the total intake mass is greater than or equal to the target intake volume is determined as the power-on time.

[0093] Specifically, when the preset air intake valve is energized, the gas in the backup air reservoir 30 enters the air path through the preset air intake valve. One opening step of the preset air intake valve corresponds to a preset energizing time. As the gas in the backup air reservoir 40 enters the control air path, the supply air pressure of the backup air reservoir 40, the gas pressure in the control air path, and the gas temperature in the control air path all change. The current gas temperature, current supply air pressure, and current control air path pressure in the control air path can be used as the initial backup air reservoir supply air pressure, initial control air path pressure, and initial control air path gas temperature for the first opening step. Combining these initial parameters, the mass of gas entering the control air path during the first opening step, the change in gas pressure in the control air path, and the change in temperature can be calculated. Based on the gas mass entering the control air path at the first opening step, the change in gas pressure and temperature within the control air path, and the initial parameters of the first opening step, the gas pressure, the gas supply pressure from the backup gas cylinder, and the gas temperature within the control air path after the first opening step can be obtained. These parameters are then used as the initial backup gas cylinder supply pressure, initial control air path pressure, and initial control air path temperature for the second opening step. This allows for the calculation of the gas mass entering the control air path at the second opening step, the change in gas pressure, and the temperature change within the control air path. This process is repeated to calculate the intake gas mass for each opening step. The total intake gas mass is obtained by summing the intake masses of each opening step. The duration of all opening steps when the total intake gas mass is greater than or equal to the target intake volume is defined as the power-on duration.

[0094] This embodiment calculates the gas mass entering the control air path, the gas pressure change, and the temperature change in each opening step based on the mass flow characteristics of the preset intake valve. This determines the initial backup gas cylinder supply pressure, the initial control air path pressure, and the initial control air path temperature for the next opening compensation. It then calculates the gas mass entering the control air path, the gas pressure change, and the temperature change in the control air path for the second opening step. This allows for accurate calculation of the gas mass entering the control air path at each opening step, making the total intake mass more closely approximate the actual intake volume, thus resulting in a more accurate determination of the power-on duration.

[0095] Optionally, the air pressure controller is specifically used for:

[0096] The gas mass input to the control air path after one opening step is calculated based on the initial backup gas cylinder supply pressure, initial control air path pressure, backup gas cylinder supply end temperature and mass flow characteristics calculation formula for each opening step of the preset air intake valve.

[0097] The formula for calculating mass flow characteristics is:

[0098]

[0099] Where dm is the gas mass input to the control gas path after the i-th opening step, and A e P1 is the effective cross-sectional area of ​​the preset intake valve; P2 is the initial backup air tank supply pressure at the i-th opening step; T1 is the initial control air circuit pressure at the i-th opening step; K is the temperature at the backup air tank supply end. G is the sonic flow coefficient; i is a positive integer greater than or equal to 1;

[0100] The gas pressure change in the control circuit after one opening step is calculated based on the first gas polytropic process formula, and the gas temperature change in the control circuit after one opening step is calculated based on the second gas polytropic process. The absolute gas temperature in the control loop is obtained by integrating and summing these values.

[0101] The formula for the polytropic process of the first gas is:

[0102] The formula for the polytropic process of the second gas is: Where n is the polytropic index, dp is the change in gas pressure in the control gas path after the i-th opening step, dt is the power-on duration corresponding to one opening step, P is the initial control gas path pressure at the i-th opening step, V is the control gas path volume, R is the gas constant of air, T is the initial gas temperature in the control gas path at the i-th opening step, and dT is the change in gas temperature in the control gas path after the i-th opening step.

[0103] Optionally, the air pressure controller is specifically used for:

[0104] The final power-on duration is determined based on the power-on duration and the stabilization duration of the preset intake valve;

[0105] The preset intake valve is energized according to the final energization duration;

[0106] When the cumulative energization time of the preset intake valve is equal to the final energization time, the actual air pressure value in the control air circuit is obtained, and the difference between the target air pressure and the actual air pressure value in the control air circuit is calculated.

[0107] Whether to continue energizing the preset intake valve is determined based on the comparison result between the difference and the preset threshold range.

[0108] Specifically, since the preset intake valve requires a certain stabilization period after being energized before it can supply air normally, the final energization period can be obtained by adding the energization period and the stabilization period of the preset intake valve, i.e., t_final = t_energized + t_stabilized. In this embodiment, when the cumulative energization period of the preset intake valve equals the final energization period, the control air pressure value measured by the control air pressure sensor is acquired again, i.e., the actual control air pressure value. The difference between the actual air pressure value and the target air pressure value is used to determine whether to continue energizing the preset intake valve, thereby making the actual air pressure value equal to or close to the target air pressure value. This enables precise control of air pressure, ensures the consistency of vehicle braking force implementation, and avoids serious safety problems.

[0109] Optionally, the air pressure controller is specifically used for:

[0110] When the difference is greater than the first preset threshold, the preset energizing extension time of the intake valve is determined according to the magnitude of the difference, and the intake valve is energized again according to the energizing extension time; wherein, the first preset threshold is a positive value;

[0111] When the difference is less than the second preset threshold, the energizing duration of the preset exhaust valve of the intake and exhaust control component is determined according to the magnitude of the difference, and the exhaust valve is controlled to discharge part of the gas in the control air circuit into the air according to the energizing duration of the preset exhaust valve; wherein, the second preset threshold is a negative value;

[0112] When the difference is within the preset range, stop energizing the preset intake valve;

[0113] When the brake main valve and the integrated intake and exhaust valve are working normally, the brake main valve is in the normally open state, and the preset exhaust valve is the exhaust valve of the integrated intake and exhaust valve; when the integrated intake and exhaust valve fails, the preset exhaust valve is the brake main valve.

[0114] The absolute values ​​of the first preset threshold and the second preset threshold can be equal or unequal, and their specific values ​​can be set as needed. A difference greater than the first preset threshold indicates that the air pressure in the control air circuit is low, requiring continued air supply. The energization extension time of the preset air intake valve can be determined based on the magnitude of the difference, for example, using the following formula: t 延长 =ΔP*K1, where K1 is the calculation coefficient of the preset intake valve, ΔP is the difference, and t 延长 To extend the power-on time, K1 is determined based on the intake characteristics of the preset intake valve.

[0115] When the difference is less than the second preset threshold, it indicates that the air pressure in the control air circuit is too high, and venting is required. The energizing duration of the preset venting valve can be determined based on the magnitude of the difference. 排气 =ΔP*K2, where K2 is the calculation coefficient for the exhaust valve, t 排气The duration of energization for the exhaust valve. K2 is determined based on the preset exhaust characteristics of the exhaust valve.

[0116] When the integrated intake and exhaust valve fails and loses its ability to regulate air pressure, the braking force of the entire vehicle can be intervened by opening and closing the brake master valve. Its control method is the same as that of the integrated intake and exhaust valve, controlling the amount of air entering the control air circuit by controlling the duration of the energization. Since the brake master valve is a two-position three-way valve and does not have the ability to hold pressure, gas pressure is maintained by continuously intake and exhaust after the energization time is completed.

[0117] Figure 3 This is a flowchart of a pneumatic controller provided in an embodiment of the present invention. The following is in conjunction with... Figure 3 The working process of the air pressure controller is explained as follows:

[0118] The air pressure controller collects air pressure signals from the air source pressure sensor and the control pipeline pressure sensor in real time to determine if there is a braking intervention command. If there is no braking intervention command, it continues to collect air pressure signals. When a braking intervention command is received, it calculates the required intake air mass to enter the control pipeline based on the gas state equation.

[0119] Then, based on the initial standby gas cylinder supply pressure, initial control gas circuit pressure, initial control gas circuit temperature, standby gas cylinder supply end temperature, and the mass flow rate characteristics of the preset intake valve for each opening step, the intake mass, gas pressure change, and gas temperature change in the control gas circuit are calculated after each opening step of the preset intake valve. Based on the gas pressure and temperature changes in the control gas circuit, the gas pressure in the control gas circuit, the standby gas cylinder supply pressure, and the gas temperature in the control gas circuit after one opening step are determined.

[0120] The gas pressure in the control gas path after one opening step, the gas pressure supplied by the backup gas cylinder, and the gas temperature in the control gas path are used as the initial backup gas cylinder supply pressure, initial control gas path pressure, and initial control gas path temperature for the next opening step. After calculating the next opening step, the intake gas mass, gas pressure change, and gas temperature change in the control gas path are input.

[0121] The intake mass of multiple opening steps is accumulated to obtain the total intake mass of all opening steps. It is then determined whether the total intake mass is greater than or equal to the required intake mass. If not, the intake mass of the input control air path, the gas pressure change within the control air path, and the gas temperature change within the control air path are calculated for the next opening step. This process of accumulating the intake mass of multiple opening steps continues until the total intake mass is greater than or equal to the required intake mass.

[0122] If so, the total energizing time corresponding to all opening steps is added to the stable time of the preset intake valve to obtain the final energizing time, and the preset intake valve is energized. After energizing, the actual air pressure of the control air circuit measured by the control air circuit pressure sensor is obtained, and it is determined whether the difference between the target air pressure and the actual air pressure is less than the first preset threshold. If not, the energizing extension time of the preset intake valve is determined based on the difference, and the preset intake valve continues to be energized. If so, it is determined whether the difference between the target air pressure and the actual air pressure is greater than the second preset threshold. If not, the energizing time of the preset exhaust valve is determined based on the difference, and the preset exhaust valve is energized. After the energizing time is reached, it is determined whether the difference between the target air pressure and the actual air pressure is less than the first preset threshold and whether it is greater than the second preset threshold.

[0123] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0124] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A commercial vehicle aftermarket air-circuit braking system, characterized in that, include: Intake and exhaust control components, quick-release valve, and pressure controller; The air inlet of the intake and exhaust control assembly is connected to the outlet of the commercial vehicle's spare air tank, and the air outlet is connected to the air inlet of the quick-release valve; the first air outlet of the quick-release valve is connected to the rear axle brake chamber of the commercial vehicle, and the second air outlet of the quick-release valve is connected to the front axle brake chamber of the commercial vehicle. The intake and exhaust control assembly includes a brake master valve and an integrated intake and exhaust valve; the intake port of the brake master valve is connected to the outlet of the commercial vehicle's spare air tank, and the outlet is connected to the intake port of the integrated intake and exhaust valve; the outlet of the integrated intake and exhaust valve is connected to the intake port of the quick-release valve. The air pressure controller is used to control the intake and exhaust control assembly to open when it detects that intervention is needed in the vehicle braking system, so that the gas in the spare air tank enters the rear axle brake chamber and the front axle brake chamber through the air outlet of the intake and exhaust control assembly. The pressure controller is used to determine the required intake air quality that needs to enter the control air path based on the difference between the target pressure and the current control air path pressure, the current gas temperature in the control air path, and the volume of the control air path. The air pressure controller is used for: When it is detected that intervention in the vehicle braking system is required, the target air pressure of the control air circuit is determined, and the temperature of the backup air reservoir supply end, the current gas temperature in the control air circuit, the current air supply pressure of the backup air reservoir measured by the air source pressure sensor, and the current control air circuit pressure measured by the control air circuit pressure sensor are obtained. The required intake air mass to enter the control air path is determined based on the control air path volume, the current gas temperature in the control air path, the current control air path pressure, and the target gas pressure. The energizing time of the preset intake valve of the intake and exhaust control component is calculated based on the temperature of the backup gas storage tank supply end, the current supply gas pressure, the current control air path pressure, the required intake air mass, and the mass flow characteristics of the intake valve. The preset air intake valve is energized according to the energizing duration, so that the standby air storage tank supplies air to the control air circuit, and the air pressure in the control air circuit reaches the target air pressure. When the brake main valve and the integrated intake and exhaust valve are working normally, the brake main valve is in the normally open state, and the preset intake valve is the intake valve of the integrated intake and exhaust valve. When the integrated intake and exhaust valve fails, the preset intake valve becomes the brake main valve. The air pressure controller is specifically used for: The gas mass input to the control air path after one opening step is calculated based on the initial backup gas cylinder supply pressure, initial control air path pressure, backup gas cylinder supply end temperature and mass flow characteristics calculation formula for each opening step of the preset air intake valve. The formula for calculating mass flow characteristics is: ； in, dm For the first i After opening the step size, input the gas mass for controlling the gas path. A e The effective cross-sectional area of ​​the preset intake valve; P1 For the first i The initial backup gas storage tank supply pressure for each opening step; P2 For the first i The initial control air pressure of the opening step size; T1 Temperature at the gas supply end of the backup gas storage tank; K G The flow coefficient for sound velocity flow; The gas pressure change in the control circuit after one opening step is calculated based on the first gas polytropic process formula, and the gas temperature change in the control circuit after one opening step is calculated based on the second gas polytropic process. The absolute gas temperature in the control loop is obtained by integrating and summing these values. The formula for the polytropic process of the first gas is: ; The formula for the polytropic process of the second gas is: Where n is the polytropic exponent, dp For the first i Each opening step controls the change in gas pressure within the gas path. dt Let P be the power-on duration corresponding to one turn-on step size. i The initial control air pressure of the opening step size. V To control the gas path volume, R Let be the gas constant of air. T For the first i The initial control gas temperature in the gas path is determined by the opening step size. dT For the first i Each opening step controls the amount of gas temperature change within the gas path. i It is an integer greater than or equal to 1.

2. The system according to claim 1, characterized in that, Also includes: Air source pressure sensor and control air circuit pressure sensor; The air source pressure sensor is used to detect the air supply pressure of the commercial vehicle's spare air tank; The control air pressure sensor is used to detect the control air pressure between the quick-release valve and the front axle brake chamber and / or the rear axle brake chamber. The pressure controller is also used to acquire the supply pressure measured by the gas source pressure sensor and the control pressure measured by the control pressure sensor.

3. The system according to claim 1, characterized in that, Also includes: Pressure relief valve, first two-way check valve, and second two-way check valve: The two air inlets of the first dual-way one-way valve are respectively connected to the first air outlet of the quick-release valve and the rear axle air tank of the commercial vehicle, and the air outlet is connected to the rear axle brake chamber; the two air inlets of the second dual-way one-way valve are respectively connected to the second air outlet of the quick-release valve and the front axle air tank of the commercial vehicle, and the air outlet is connected to the front axle brake chamber. The pressure relief valve is located in the air path between the air inlet of the second two-way one-way valve and the quick-release valve.

4. The system according to claim 3, characterized in that, The outlet of the first dual-way one-way valve is also connected to the trailer brake chamber.

5. The system according to claim 1, characterized in that: The air pressure controller is specifically used for: Based on the initial standby air tank supply pressure, initial control air circuit pressure, initial control air circuit temperature, standby air tank supply end temperature, and the mass flow rate characteristics of the preset air intake valve, the intake mass, gas pressure change, and gas temperature change of the control air circuit are calculated after each opening step of the preset air intake valve. The gas pressure in the control gas path, the gas supply pressure of the backup gas cylinder, and the gas temperature in the control gas path are determined based on the gas pressure change and the gas temperature change in the control gas path after each opening step. The gas pressure in the control gas path after one opening step, the gas pressure supplied by the backup gas cylinder, and the gas temperature in the control gas path are used as the initial backup gas cylinder supply pressure, initial control gas path pressure, and initial control gas path temperature for the next opening step. After calculating the next opening step, the intake gas mass, gas pressure change, and gas temperature change of the control gas path are input. The intake mass of multiple opening steps is accumulated to obtain the total intake mass of all opening steps. The time of all opening steps when the total intake mass is greater than or equal to the target intake volume is determined as the power-on time.

6. The system according to claim 1, characterized in that, The air pressure controller is specifically used for: The final power-on duration is determined based on the power-on duration and the stabilization duration of the preset intake valve; The preset intake valve is energized according to the final energizing duration; When the cumulative energizing time of the preset intake valve is equal to the final energizing time, the actual air pressure value in the control air circuit is obtained, and the difference between the target air pressure and the actual air pressure value in the control air circuit is calculated. Whether to continue energizing the preset intake valve is determined based on the comparison result between the difference and the preset threshold range.

7. The system according to claim 6, characterized in that, The air pressure controller is specifically used for: When the difference is greater than a first preset threshold, the power-on extension duration of the preset intake valve is determined according to the magnitude of the difference, and the preset intake valve is powered on again according to the power-on extension duration; wherein, the first preset threshold is a positive value; When the difference is less than the second preset threshold, the energizing duration of the preset exhaust valve of the intake and exhaust control component is determined according to the magnitude of the difference, and the preset exhaust valve is controlled to discharge part of the gas in the control air path into the air according to the energizing duration of the preset exhaust valve; wherein, the second preset threshold is a negative value; When the difference is within a preset range, power is stopped to the preset intake valve; When the brake master valve and the integrated intake and exhaust valve are working normally, the preset exhaust valve is the exhaust valve of the integrated intake and exhaust valve; when the integrated intake and exhaust valve malfunctions, the preset exhaust valve is the brake master valve.

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