Vehicle retarding system, vehicle and control method thereof

Abstract

The invention provides a vehicle retarding system, a vehicle and a control method of the vehicle. The vehicle retarding system comprises a hydraulic torque converter, a retarding hydraulic pump, a proportional overflow, a variable speed pump, a sequence valve, a rotating speed sensor, a pressure sensor, a temperature sensor and a controller. The hydraulic torque converter is connected with the retarding hydraulic pump and the variable-speed pump through transfer gears, the retarding hydraulic pump provides braking power for a vehicle, and the variable-speed pump is mainly used for providing oil inlet flow for the hydraulic torque converter. An outlet of the retarding hydraulic pump is connected with a pressure sensor, a proportional overflow valve and a radiator; an outlet of the variable-speed pump is connected with a sequence valve and a gearbox operating valve, and a temperature sensor is arranged at an oil outlet of the hydraulic torque converter; an output rotating speed sensor is arranged on an output shaft of the hydraulic torque converter; the retarding hydraulic pump, the pressure sensor, the proportional overflow valve, the temperature sensor, the rotating speed sensor and the engine rotating speed sensor are all connected with the controller and controlled by a built-in program of the controller.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of vehicle retarder system, in particular to a vehicle retarder system, vehicle and control method thereof. BACKGROUND

[0002] The conventional service brake equipped in current vehicles can only have continuous working ability within certain limits. In the case of heavy vehicles with high total weight and sometimes high energy, long time steady state braking when going down long slope will cause excessive heat and overload of the friction type service brake, thus leading to the decline of braking efficiency.

[0003] The two types of braking modes that can produce and maintain braking force for a long time and have no visible wear as the auxiliary device of conventional service brake are currently engine brake system and retarder. The engine brake system is complex in manufacturing process, high in cost and limited in braking capacity, and cannot fully meet the needs of heavy vehicles. The retarder as an independent device needs to be separately arranged in the vehicle chassis, which significantly increases the difficulty of space arrangement and use cost. Among them, the torque converter can convert part of the vehicle kinetic energy into heat energy through the internal working fluid by using its reverse transmission characteristics during the vehicle downhill process, thereby reducing the vehicle speed. Although the reverse transmission characteristics of the torque converter can provide a certain braking force, its main role is to provide additional assistance in the process of light to moderate deceleration, and it does not have the ability to provide main braking force for the vehicle.

[0004] A hydraulic torque converter assembly, a vehicle and a control method are disclosed in patent CN120292236A. The hydraulic torque converter assembly includes a hydraulic torque converter, a pressure regulating assembly, and a rotation direction regulating assembly. The pressure regulating assembly is connected to the oil inlet of the hydraulic torque converter and is used to regulate the oil inlet pressure of the hydraulic torque converter. The rotation direction regulating assembly is connected to the output shaft and is used to change the rotation direction of the output shaft. After obtaining the deceleration command, the vehicle speed and the oil inlet pressure of the hydraulic torque converter are obtained and the rotation direction regulating assembly is controlled to change the rotation direction of the output shaft. The pressure regulating assembly is controlled to regulate the oil inlet pressure of the hydraulic torque converter to regulate the output speed of the hydraulic torque converter. However, during actual operation of the hydraulic torque converter assembly, the following problems exist: when the vehicle is descending a long slope, the rotation direction of the output shaft is changed by the rotation direction regulating assembly, and the reverse rotation characteristic of the torque converter is used to achieve the requirement of long-time deceleration braking of the vehicle. When the vehicle is in normal driving traction conditions, the torque converter rotates normally. Therefore, the performance of the torque converter under two opposite motions (normal rotation (normal driving traction conditions) and reverse rotation (deceleration braking conditions)) must be considered in the design of the torque converter impeller. Since the size and shape (especially the blade angle) of the torque converter impeller directly affect its performance, it is impossible to achieve high efficiency in both opposite rotation motions. Therefore, the torque converter is usually designed to be mainly used in normal rotation (traction conditions, high efficiency operation), while the torque converter operates at low efficiency when it is reversed. At this time, the torque converter generates a large amount of heat and requires a larger oil flow and a larger power cooling system. SUMMARY

[0005] To solve the technical problems existing in the prior art, the present application provides a vehicle deceleration system, a vehicle and a control method thereof.

[0006] To achieve the above-mentioned purposes, the technical solutions adopted by the present application are as follows: In a first aspect, the present application provides a vehicle deceleration system, which comprises a hydraulic torque converter, a deceleration hydraulic pump, a proportional overflow valve, a variable speed pump, a sequence valve, a speed sensor, a pressure sensor, a temperature sensor and a controller. The hydraulic torque converter is connected to the deceleration hydraulic pump and the variable speed pump through a transfer gear, the deceleration hydraulic pump provides braking power for the vehicle, and the variable speed pump mainly provides oil flow for the hydraulic torque converter. The outlet oil line of the deceleration hydraulic pump is connected to the pressure sensor, the proportional overflow valve and the radiator, and then connected to the oil return tank. The oil outlet of the hydraulic torque converter is provided with a temperature sensor, and the output shaft of the hydraulic torque converter is provided with an output speed sensor. The deceleration hydraulic pump, the pressure sensor, the proportional overflow valve, the temperature sensor, the speed sensor and the engine speed sensor are all connected to the controller and controlled by the built-in program of the controller.

[0007] The application is applied to the long-downhill working condition of heavy vehicles, and vehicle speed is controlled by the reverse transmission performance of a hydraulic torque converter and the power consumption of a hydraulic pump, that is, the mechanical brake thermal load of the vehicle is reduced by the combined action of hydraulic force and hydraulic pressure, the brake failure hidden danger caused by poor heat dissipation of the dry clutch during long downhill driving of the vehicle is solved, and the active safety is improved.

[0008] As a further technical solution, the oil outlet of the hydraulic torque converter is connected to the radiator, and the radiator is connected to the oil return tank.

[0009] As a further technical solution, the two retarding hydraulic pumps use the same oil source and finally return to the same radiator oil tank.

[0010] As a further technical solution, the outlet oil circuit of the variable speed pump is connected to a sequence valve and then connected to the oil inlet of the hydraulic torque converter.

[0011] In a second aspect, based on the vehicle retarding system described above, the application further provides a control method, as follows: The engine speed sensor detects the engine speed signal; The output speed sensor detects the output speed signal of the hydraulic torque converter; The pressure sensor detects the retarding hydraulic pump pressure signal; The controller obtains the engine speed signal, the output speed signal of the hydraulic torque converter, and the retarding hydraulic pump pressure signal, processes the signals, obtains the control value of the proportional electromagnet in the proportional electromagnetic relief valve, and controls the proportional electromagnet current after a series of signal conversions. The proportional electromagnet further adjusts the power of the retarding hydraulic pump by controlling the displacement of the variable displacement pump or the pressure of the proportional electromagnetic relief valve, and finally controls the braking capacity of the vehicle.

[0012] In a third aspect, the application further provides a vehicle comprising the vehicle retarding system described above.

[0013] As a further technical solution, the output shaft of the hydraulic torque converter is connected to the variable speed drive axle.

[0014] In a fourth aspect, the application further provides a vehicle control method, specifically as follows: When the vehicle is in normal road routine driving state, the slow speed system is closed, the controller gives the slow speed hydraulic pump and the proportional overflow valve the minimum current, at this time, the slow speed hydraulic pump has the minimum displacement, and the proportional overflow valve pressure is basically zero; at this time, the slow speed hydraulic pump consumes the minimum power, and the slow speed system is in standby state; if at this time, the vehicle is normally decelerated, the throttle is released, and the engine speed is reduced, when the output speed of the hydraulic torque converter is greater than the input speed of the hydraulic torque converter, the reverse transmission characteristics of the hydraulic torque converter will provide additional help for the vehicle braking, and the conventional brake system provides the main braking force for the vehicle; at the same time, the gear position signal of the vehicle slow speed system is steplessly adjusted according to the downhill slope and the vehicle speed, the controller processes and calculates according to the received slow speed system gear position signal and the collected engine speed signal according to the built-in program, and the slow speed hydraulic pump outlet pressure and displacement value calculated by the operation are finally converted into signal values to send control current signals to the slow speed hydraulic pump and the proportional electromagnetic overflow valve, and after receiving the current signals, the slow speed hydraulic pump and the proportional electromagnetic overflow valve are automatically adjusted according to the control current signals and reach the specified displacement or outlet pressure.

[0015] The beneficial effects of the present application are as follows: The vehicle slow speed system can steplessly adjust the braking power of the vehicle by controlling the displacement of the slow speed hydraulic pump and the pressure of the proportional overflow valve when the vehicle is in long downhill working condition, thereby meeting the requirement of long time stable braking of the vehicle, reducing the thermal load of the mechanical brake of the vehicle, solving the brake failure hidden danger caused by poor heat dissipation of the dry clutch in long downhill, and improving the active safety. The present application finally converts the potential energy of the vehicle in long downhill into heat energy through the combined action of hydraulic force and hydraulic pressure, and dissipates the heat energy through the radiator. The reverse transmission performance of the torque converter converts a small part of the kinetic energy of the vehicle into heat energy, and the other part of the kinetic energy drives the slow speed hydraulic pump through the hydraulic torque converter to convert the kinetic energy into hydraulic energy, and further converts the hydraulic energy into heat energy through the proportional overflow valve, and finally dissipates the heat energy through the radiator. The slow speed hydraulic pump and the proportional overflow valve are steplessly controlled to brake the power, which responds quickly to ensure the stability of the vehicle. The engine speed and the torque converter turbine speed are detected by the speed sensor, the slow speed hydraulic pump outlet pressure is detected by the pressure sensor, and the oil temperature is detected by the temperature sensor. The speed, pressure and temperature signals are transmitted to the controller to achieve the effect of stabilizing the speed through program control.

[0016] Further, compared with the hydraulic torque converter assembly, the vehicle and the control method in the prior art, the vehicle of the present application runs in the normal rotation direction with high efficiency in the normal driving state and the long downhill slow speed driving state, and the oil supply system and the cooling system do not change; the present application steplessly brakes through the combined action of hydraulic force and hydraulic pressure, that is, through the reverse transmission characteristics of the torque converter and the slow speed hydraulic pump to work and convert energy with high efficiency, the torque converter rotates in one direction with high efficiency, and the slow speed hydraulic pump is set as the main system of the slow speed brake to convert braking power energy. Attached Figure Description

[0017] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0018] Figure 1 This is a schematic diagram of the deceleration system provided by the present invention; Figure 2 This is a schematic diagram of the integrated hydraulic torque converter and retarder hydraulic pump provided by the present invention. Figure 3 This is a schematic diagram of the control principle provided by the present invention; In the diagram: 1. Hydraulic torque converter, 2. Transfer gear, 3. Retarder hydraulic pump, 4. Variable speed pump, 5. Sequence valve, 6. Controller, 7. Pressure sensor, 8. Proportional relief valve, 9. Engine speed sensor, 10. Temperature sensor, 11. Radiator, 12. Torque converter speed sensor. Detailed Implementation

[0019] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0020] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless otherwise expressly indicated by the invention, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. Definitions: Steady-state braking: Its function is to prevent unwanted acceleration when the vehicle is going downhill.

[0021] Reverse transmission condition of hydraulic torque converter: When the turbine speed approaches or exceeds the pump wheel speed (e.g., when the vehicle is coasting or going downhill), the fluid flow direction reverses and impacts the back of the guide wheel. At this time, the turbine shaft inputs power, which is consumed by the working fluid inside the hydraulic torque converter and converted into heat energy.

[0022] As introduced in the background, in order to solve the above technical problems, the present application provides a vehicle retarding system, a vehicle and a control method thereof, which can make the vehicle meet the requirement of stable braking by the reverse transmission performance of the torque converter and the power consumption of the retarding hydraulic pump when the vehicle is working on a long downhill; the retarding hydraulic pump and the proportional overflow valve can steplessly adjust the displacement of the retarding hydraulic pump and the pressure of the proportional overflow valve according to different braking torque requirements, so as to control the braking power to meet the requirements of different slopes when the vehicle is working on a long downhill and keep the stability of the vehicle.

[0023] The present application will be further described below in combination with the drawings and examples, but it is not used as the basis for limiting the present application.

[0024] Examples: The present example provides a vehicle retarding system and a control method thereof, the structure and principle of which are shown in Figs. Figure 1 , Figure 2 The vehicle retarding system comprises a hydraulic torque converter 1, a retarding hydraulic pump 3, a proportional overflow valve 8, a variable displacement pump 4, a sequence valve 5, a torque converter speed sensor 12, an engine speed sensor 9, a pressure sensor 7, a temperature sensor 10, a controller and the like. The hydraulic torque converter 1 is connected to the retarding hydraulic pump 3 and the variable displacement pump 4 through a transfer gear 2, wherein the functions of the retarding hydraulic pump 3 and the variable displacement pump 4 in the present example are completely different, specifically, the retarding hydraulic pump 3 mainly provides braking power for the vehicle, and the variable displacement pump 4 mainly provides oil flow for the hydraulic torque converter 1, but the retarding hydraulic pump 3 and the variable displacement pump 4 use the same oil source and finally return to the oil tank through the same radiator. The oil outlet of the retarding hydraulic pump 3 is connected to the oil tank through the oil path, the pressure sensor 7, the proportional overflow valve 8 and the radiator 11; the outlet of the variable displacement pump 4 is connected to the oil inlet of the hydraulic torque converter 1 through the sequence valve 5 to provide oil flow for the hydraulic torque converter 1; the oil outlet of the hydraulic torque converter 1 is provided with the temperature sensor 10, the input shaft of the hydraulic torque converter 1 is provided with the engine speed sensor 9, the output shaft of the hydraulic torque converter 1 is connected to the drive axle of the transmission, and the torque converter speed sensor 12 is arranged on the output shaft; the retarding hydraulic pump 3, the pressure sensor 7, the proportional overflow valve 8, the temperature sensor 10, the torque converter speed sensor 12 and the engine speed sensor 9 are connected to the controller 6 and controlled by the built-in program of the controller 6.

[0025] Further, the proportional electromagnetic overflow valve is selected for the proportional overflow valve 8 in the present example.

[0026] Further, the turbine speed sensor is selected for the torque converter speed sensor 12 in the present example.

[0027] Further, the vehicle retarder system and the control method thereof are as shown in the specification, specifically as follows: Figure 3 Further, the vehicle retarder system and the control method thereof are as shown in the specification, specifically as follows: The engine speed sensor 9 is used to detect the engine speed, i.e. the input speed of the torque converter; The torque converter speed sensor 12 is used to detect the output speed of the torque converter; The pressure sensor 7 is used to detect the outlet pressure of the retarder hydraulic pump; The operator can continuously adjust the retarder gear position according to the downhill slope and vehicle speed. The detected input speed and output speed signals of the torque converter 1, the outlet pressure signal of the retarder hydraulic pump 3, the retarder gear position signal, and the outlet oil temperature signal of the torque converter 1 are communicated with the controller through data lines. After processing, the controller gives the retarder hydraulic pump 3 and the proportional overflow valve 8 corresponding current values, so as to control the displacement and outlet pressure of the retarder hydraulic pump 3, adjust the power of the retarder hydraulic pump 3, i.e. the braking power, and realize the opening, closing and stepless control of the retarder system.

[0028] Further, the outlet oil temperature signal of the torque converter 1 is used to control the safe temperature of the retarder system. If the temperature exceeds the safe temperature value, an alarm will be triggered to remind the operator to reduce the braking power of the retarder system and introduce a conventional mechanical brake as a substitute.

[0029] Further, in the retarder system, the controller includes a converter, a computer and a proportional valve amplifier connected thereto. The proportional valve amplifier is connected with the proportional electromagnet, and the converter is connected with the speed sensor and the pressure sensor respectively.

[0030] Further, the control method of the vehicle retarder system during vehicle operation is as follows: When the vehicle is in normal road and regular driving state, the retarder system is closed, the controller gives the minimum current to the retarder hydraulic pump 3 and the proportional overflow valve 8, at this time, the displacement of the retarder hydraulic pump 3 is minimum, the pressure of the proportional overflow valve 8 is basically zero, so the power consumption of the retarder hydraulic pump 3 is minimum, and the retarder system is in standby state; if at this time the vehicle is normally decelerated by releasing the throttle, the engine speed is reduced, until the output speed of the torque converter 1 (i.e. the turbine speed of the torque converter) is greater than the input speed of the torque converter 1, the reverse transmission characteristic of the torque converter 1 will provide additional help for the vehicle braking, and the conventional brake system provides the main braking force for the vehicle; at the same time, the gear position signal of the vehicle retarder system is steplessly adjusted according to the downhill slope and the vehicle speed, the controller processes and calculates according to the received retarder system gear position signal and the collected engine speed signal according to the built-in program, and the calculated retarder hydraulic pump outlet pressure and displacement value are finally converted into signal values to send control current signals to the retarder hydraulic pump 3 and the proportional electromagnetic overflow valve 8, the displacement of the retarder hydraulic pump and the pressure of the proportional overflow valve 8 are in direct proportional relationship with the control current of the proportional electromagnet acting on the inside, after receiving the current signal, the retarder hydraulic pump 3 and the proportional electromagnetic overflow valve 8 are automatically adjusted according to the control current signal and reach the specified displacement or outlet pressure, and the power consumption of the retarder hydraulic pump 3 is the required braking power.

[0031] Specifically, the control principle of the present application is described as follows, the calculation formula involved in the vehicle retarder system control method in the embodiment is as follows: (1) Hydraulic pump power

[0032] Wherein, T: torque, n hydraulic pump speed; (2) Torque

[0033] Wherein, V g : hydraulic pump displacement, p: hydraulic pump outlet pressure, η: hydraulic pump mechanical efficiency (constant value) (3) Downhill force

[0034] Wherein, m: vehicle mass (constant value), g: gravitational constant 9.8 N / kg, α: downhill angle, unit: °.

[0035] (4) Vehicle braking torque

[0036] Wherein: i ∑ : total transmission ratio of the transmission system (constant value), η ∑ : total efficiency of the transmission system (basic constant value), R: wheel radius (constant value) From the above, the hydraulic pump power is determined by the rotation speed, pressure and displacement, and the rotation speed, pressure and displacement are all inversely proportional to the power; the vehicle braking power is determined by the vehicle mass, downhill angle, total transmission ratio of the drive train, total efficiency of the drive train, vehicle radius, and in actual working conditions, the rest of the factors are ignored, and only the downhill angle is proportional to the braking power; the power of the required retarder hydraulic pump 3 can be matched and calculated in the initial design selection. In the vehicle long downhill working condition, the operator adjusts the retarder system gear signal steplessly according to the downhill slope and vehicle speed (the size of the retarder system gear signal is proportional to the size of the braking power), the controller processes and calculates according to the received retarder system gear signal and the collected engine speed signal according to the built-in program, and the outlet pressure and displacement value of the retarder hydraulic pump 3 calculated by the operation is finally converted into a signal value to send a control current signal to the retarder hydraulic pump 3 and the proportional overflow valve 8, and the displacement of the retarder hydraulic pump 3 and the pressure of the proportional overflow valve 8 are proportional to the control current of the proportional electromagnet acting on the inside, and after receiving the current signal, the retarder hydraulic pump 3 and the proportional overflow valve 8 are automatically adjusted according to the control current signal and reach the specified displacement or outlet pressure, and the power consumption of the retarder hydraulic pump is the required braking power.

[0037] The present application detects the engine speed signal, the torque converter output speed signal and the retarder hydraulic pump pressure signal through various sensors, and each signal communicates with the controller through a data line, the controller converts each detected signal into a digital quantity that can be recognized by a computer, and the computer calculates the control value of the proportional electromagnet in the retarder hydraulic pump and the proportional overflow valve through the built-in program after reading, the control value of the proportional electromagnet controls the proportional electromagnet current after a series of signal conversion, and the proportional electromagnet further adjusts the power of the retarder hydraulic pump by controlling the displacement of the variable displacement pump or the pressure of the proportional overflow valve, and finally controls the braking capacity of the vehicle.

[0038] That is, the vehicle retarder system in the embodiment can steplessly adjust the braking power of the vehicle by controlling the displacement of the retarder hydraulic pump and the pressure of the proportional overflow valve when the vehicle is in a long downhill working condition, and thus the requirement of long-time stable braking of the vehicle is met, so as to reduce the mechanical brake heat load of the vehicle, solve the brake failure hidden danger caused by poor heat dissipation of the dry clutch in long downhill, and improve the active safety; through the combined action of hydraulic and hydraulic, the potential energy of the vehicle in long downhill is finally converted into heat energy and dissipated through the radiator; the reverse transmission performance of the torque converter converts a small part of the kinetic energy of the vehicle into heat energy, and the other part of the kinetic energy drives the retarder hydraulic pump through the hydraulic torque converter to convert the kinetic energy into hydraulic energy, and further converts the hydraulic energy into heat energy through the proportional overflow valve, and finally the heat energy is dissipated through the radiator; Adopt the stepless control brake power of retarder hydraulic pump and proportional overflow valve, the response is quick guarantee the stability of vehicle. Through the engine speed sensor, the torque converter turbine speed, the pressure sensor detects the retarder hydraulic pump outlet pressure, the temperature sensor detects the oil temperature, the speed, pressure, temperature signal transmission to the controller, through the program control to achieve the effect of stable speed.

[0039] Compared with the prior art, the vehicle retarder system disclosed in the embodiment transmits various signals collected by various sensors to the controller when the vehicle is in long downhill working condition, and gives corresponding current values of the retarder hydraulic pump and the proportional overflow valve after internal program operation; the retarder hydraulic pump adjusts the pump displacement in proportion to the solenoid current through the electronic control of the proportional solenoid carried by the retarder hydraulic pump; the proportional overflow valve adjusts the overflow pressure in proportion to the solenoid current through the electronic control of the proportional solenoid carried by the proportional overflow valve. The displacement of the retarder hydraulic pump and the outlet pressure of the retarder hydraulic pump together determine the power consumption of the hydraulic pump, that is, the brake power provided for the vehicle.

[0040] The application is applied to the long downhill working condition of heavy vehicles, and the vehicle speed is controlled by the reverse transmission performance of the hydraulic torque converter and the power consumption of the hydraulic pump, that is, the mechanical brake thermal load of the vehicle is reduced by the combined action of the hydraulic torque converter and the hydraulic pump, the brake failure hidden danger caused by poor heat dissipation of the dry clutch during long downhill driving of the vehicle is solved, and the active safety is improved.

[0041] The embodiment also provides a vehicle, and the vehicle comprises the retarder system described above. Since the retarder system described above is arranged in the vehicle, the vehicle also has all the advantages described above. In some embodiments, the vehicle provided by the application can be any appropriate type of vehicle, such as a car, an electric vehicle, a truck, a small car, etc.

[0042] Finally, it should be noted that the relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations.

[0043] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A vehicle retarding system, characterized in that, Includes hydraulic torque converter, retarder hydraulic pump, proportional relief pump, variable speed pump, speed sensor, pressure sensor, temperature sensor and controller; The hydraulic torque converter is connected to a retarder hydraulic pump and a transmission pump via a transfer gear. The retarder hydraulic pump provides braking power to the vehicle, and the transmission pump mainly provides oil flow to the hydraulic torque converter. A pressure sensor, a proportional relief valve, and a radiator are connected to the outlet oil line of the retarder hydraulic pump before it is connected to the return oil tank. A temperature sensor is installed at the oil outlet of the hydraulic torque converter. An output speed sensor is installed on the output shaft of the hydraulic torque converter. The retarder hydraulic pump, pressure sensor, proportional relief valve, temperature sensor, speed sensor, and engine speed sensor are all connected to the controller and controlled by the controller's built-in program.

2. The vehicle retarding system as described in claim 1, characterized in that, The oil outlet of the hydraulic torque converter is connected to the radiator and then to the oil return tank.

3. The vehicle retarding system as described in claim 1, characterized in that, Both of the aforementioned slow-speed hydraulic pumps use the same oil source and ultimately return to the oil tank via the same radiator.

4. The vehicle retarding system as described in claim 1, characterized in that, The outlet oil circuit of the variable speed pump is connected to the sequence valve and then to the inlet of the hydraulic torque converter.

5. The control method for the vehicle retarding system as described in any one of claims 1-4, characterized in that, as follows: The engine speed sensor detects the engine speed signal; The output speed sensor detects the output speed signal of the hydraulic torque converter; The pressure sensor detects the pressure signal from the slow-speed hydraulic pump. After acquiring the engine speed signal, the output speed signal of the hydraulic torque converter, and the pressure signal of the retarder hydraulic pump, the controller processes the signals to obtain the control values ​​of the proportional electromagnet in the retarder hydraulic pump and the proportional solenoid relief valve. The control value of the proportional electromagnet is converted into a series of signals to control the current of the proportional electromagnet. The proportional electromagnet further adjusts the power of the retarder hydraulic pump by controlling the displacement of the variable pump or the pressure of the proportional solenoid relief valve, and finally controls the braking ability of the vehicle.

6. A vehicle, characterized in that, It includes the vehicle deceleration system as described in any one of claims 1-5.

7. The vehicle as described in claim 6, characterized in that, The output shaft of the hydraulic torque converter is connected to the variable speed drive axle.

8. The vehicle control method as described in claim 6, characterized in that, Specifically as follows: When the vehicle is in normal driving condition on a normal road, the retarding system is turned off, and the controller provides the retarding hydraulic pump and proportional relief valve with the minimum current. At this time, the retarding hydraulic pump has the minimum displacement and the proportional relief valve pressure is basically zero. At this time, the retarding hydraulic pump consumes the minimum power, and the retarding system is in standby mode. If the vehicle decelerates normally and the accelerator is released, causing the engine speed to decrease, when the output speed of the torque converter is greater than the input speed, the reverse transmission characteristic of the torque converter will provide additional assistance to the vehicle's braking. The conventional braking system provides the main braking force for the vehicle. At the same time, the vehicle's retarding system gear signal is continuously adjusted according to the downhill slope and vehicle speed. The controller processes and calculates the received retarding system gear signal and the collected engine speed signal according to its built-in program. The calculated retarding hydraulic pump outlet pressure and displacement value are finally converted into signal values ​​and sent to the retarding hydraulic pump and the proportional electromagnetic relief valve as control current signals. After receiving the current signal, the retarding hydraulic pump and the proportional electromagnetic relief valve automatically adjust according to the control current signal to achieve the specified displacement or outlet pressure.

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