A shear-thickening magnetorheological fluid composite brake retarder and its control method

Abstract

The present invention discloses a shear-thickening magnetorheological fluid composite brake retarder and a control method thereof. When braking is required, the clutch operatively connects the transmission shaft and the hollow input shaft of the retarder, and determines whether the coil is energized according to the required braking force: when a low braking torque is required, the coil is not energized, and the shear-thickening fluid generates shear resistance; when a high braking torque is required, the coil is energized, and the magnetorheological effect and the shear-thickening effect are combined to realize dual control of the magnetic field and the shear rate field, thereby achieving the effect of stepless regulation of the braking force of the retarder; the present invention also provides cooling water flow channels inside the hollow input shaft of the retarder, inside the rotor, and inside the housing, and is connected to the radiator, which can cool the core area of ​​the working fluid, improve the cooling efficiency, and thus improve the stability of the retarder.

Description

Technical Field

[0001] The invention relates to the technical field of automobile shear thickening magnetorheological fluid retarders, and in particular to a shear thickening magnetorheological fluid composite brake retarder and a control method thereof. Background Art

[0002] Due to the many curves and steep roads in mountainous areas, medium- and heavy-duty vehicles like long-distance buses and trucks frequently encounter long descents. Consequently, commercial vehicles have been developing towards high-speed, heavy-load operation. As vehicle load capacities and speeds increase, the braking loads on these vehicles also increase, requiring frequent and continuous braking, leading to frequent brake system failures. If these braking loads were solely borne by the vehicle's braking system, not only would braking performance deteriorate, but frequent braking could also lead to overheating of the brake drums and brake pads, potentially causing a range of accidents such as vehicle deviation, skidding, and rear-end collisions.

[0003] As an auxiliary braking device for vehicles, retarders, installed on the vehicle's transmission system, divert the load from the wheel brakes, ensuring heat dissipation and reducing wear on the main brakes. Currently, the main auxiliary braking devices used in vehicles include hydraulic retarders, eddy current retarders, and magnetorheological disc retarders. Hydraulic retarders are complex, costly, slow to respond, and consume a lot of fuel. Eddy current retarders are large and heavy, requiring a high power consumption during braking, are significantly affected by ambient temperature, and have poor heat dissipation. Furthermore, eddy current retarders only activate after the vehicle speed reaches a certain level, limiting the speed range for auxiliary braking. Magnetorheological disc retarders, whether they generate resistance through the shear force of the magnetorheological fluid or through friction, gradually increase their retarding effect as the magnetic field strength increases. However, as the magnetic field strength continues to increase, the retarding capacity increases more slowly, resulting in reduced braking efficiency and low energy utilization. They also experience wear and pose heat dissipation challenges. Summary of the Invention

[0004] In view of the shortcomings of the existing technology, the present invention provides a shear thickening magnetorheological fluid composite brake retarder and a control method thereof, which has the characteristics of low energy consumption, large braking torque, high working stability, and good heat dissipation performance.

[0005] The present invention achieves the above technical objectives through the following technical means.

[0006] A shear-thickening magnetorheological fluid composite brake retarder, comprising:

[0007] The retarder body comprises a rotor, a housing, a hollow retarder input shaft, and a coil; the rotor is located inside the housing and forms a working chamber with the housing, wherein the working chamber is filled with a polymer liquid; the hollow retarder input shaft sequentially penetrates the housing and the rotor, and the rotor is fixedly connected to the hollow retarder input shaft, and the housing is rotatably connected to the hollow retarder input shaft;

[0008] The coil is embedded in the housing and arranged axially along the outer circumference of the rotor; the coil is powered by an on-board power supply;

[0009] The retarder hollow input shaft is connected with the transmission shaft through a clutch.

[0010] In the above technical solution, the rotor includes two connecting circular plates and a plurality of blades evenly arranged between the two connecting circular plates. A working chamber flow channel is left between the outer periphery of the blade and the inner side wall of the working chamber. Two variable-section flow channels are evenly opened on the blade and penetrate the blade body. The cross-sectional area of ​​the variable-section flow channel changes from large to small from one side of the rotor rotation direction.

[0011] The above technical solution also includes:

[0012] The heat dissipation system includes a radiator, a variable frequency speed regulating water pump, an electric motor and a cooling water flow channel; cooling water flow channels are provided inside the outermost part of the fan blade, inside the hollow input shaft of the retarder and inside the housing, and the cooling water flow channel inside the hollow input shaft of the retarder is connected to the cooling water flow channel inside the outermost part of the fan blade and inside the right housing;

[0013] The variable frequency speed regulating water pump, the liquid inlet on the hollow input shaft of the retarder, the cooling water flow channel, the liquid outlet on the shell and the radiator are connected through pipelines;

[0014] The electric motor is electrically connected to the variable frequency speed regulating water pump.

[0015] The above technical solution also includes:

[0016] The electronic control system includes a vehicle controller, a retarder controller, a working chamber temperature sensor and a water temperature sensor. The working chamber temperature sensor is arranged in the working chamber, and the water temperature sensor is arranged next to the liquid outlet. The information collected by the working chamber temperature sensor and the water temperature sensor is transmitted to the vehicle controller. The retarder controller is respectively connected to the electric motor, the vehicle power supply and the vehicle controller.

[0017] In the above technical solution, the heat dissipation system further includes a heat dissipation fan, which is coaxially arranged on the hollow input shaft of the retarder.

[0018] In the above technical solution, a magnetic isolation ring is provided on the outer edge of the coil.

[0019] A control method for a shear-thickening magnetorheological fluid composite brake retarder:

[0020] Step (1): Determine whether there is a deceleration signal input:

[0021] If there is a signal input, execute step (2);

[0022] If there is no signal input, the vehicle runs normally and the clutch does not work;

[0023] Step (2): Determine whether there is a composite brake signal input:

[0024] If there is a signal input, execute step (3);

[0025] If there is no signal input, the coil is not energized, the retarder performs single braking, and step (4) is executed;

[0026] Step (3): Determine whether there is a constant speed signal input:

[0027] If a constant speed signal is input, the coil is energized, the real-time vehicle speed when the coil starts working is set to the set value, and step (5) is executed;

[0028] If there is no constant speed signal input, the coil is energized and it is determined whether the slip ratio is greater than the set value. If the slip ratio is greater than the set value, the current of the coil is adjusted, thereby adjusting the braking torque until the slip ratio is less than the set value. Otherwise, the current of the coil is maintained and step (1) is executed.

[0029] Step (4): Determine whether the current braking torque meets the slow braking requirement:

[0030] If the deceleration braking requirement is met, the current single braking is maintained and it is determined whether the deceleration condition has ended. If so, step (6) is executed. If not, the retarder performs a single braking and determines whether the deceleration condition has ended until the deceleration condition has ended.

[0031] If the deceleration braking requirement is not met, then execute step (3);

[0032] Step (5): Continue to collect real-time vehicle speed and determine whether the real-time vehicle speed is equal to the set value:

[0033] If the real-time vehicle speed is equal to the set value, determine whether the deceleration condition is ended: if it is ended, execute step (6); otherwise, continue to collect the real-time vehicle speed and determine whether the real-time vehicle speed is equal to the set value;

[0034] If the real-time vehicle speed is not equal to the set value, determine whether the deceleration condition is ended: if it is ended, execute step (6); otherwise, adjust the current of coil (15), continue to collect the real-time vehicle speed and determine whether the real-time vehicle speed is equal to the set value;

[0035] Step (6) exits the braking state.

[0036] Furthermore, the retarder can perform joint braking control with the vehicle main brake, specifically:

[0037] Step (1): Determine whether the real-time vehicle speed is greater than the minimum set value V1:

[0038] If the real-time vehicle speed is greater than the minimum set value V1, then execute step (2);

[0039] Otherwise, combined braking control is performed, in which the retarder performs single braking, and the main brake manually adjusts its braking force according to demand, and executes step (3);

[0040] Step (2): Determine the relationship between the real-time vehicle speed and the set values ​​V2 and V3:

[0041] If the real-time vehicle speed is less than or equal to V2, then execute step (4);

[0042] If the real-time vehicle speed is greater than V2 but less than V3, then execute step (5);

[0043] If the real-time vehicle speed is greater than or equal to V3, then execute step (6);

[0044] Step (3): Determine whether the slip rate of each wheel reaches a threshold value: If the slip rate reaches the threshold value, the ABS anti-lock braking system is triggered to intervene to ensure that the slip rate of each wheel is lower than the threshold value; otherwise, the current braking mode is maintained and step (9) is executed;

[0045] Step (4): The main brake does not intervene in the operation, the retarder performs compound braking, and the current of the coil is adjusted according to the braking demand to perform stepless adjustment of the braking force, and step (7) is executed;

[0046] Step (5): The vehicle performs combined braking control, and the retarder performs compound braking at the same time. The current of the coil is adjusted according to the braking demand to perform stepless adjustment of the braking force. The main brake adjusts its braking force for the person according to the demand, and then executes step (8);

[0047] Step (6): The vehicle performs combined braking control, and the retarder performs compound braking at the same time, inputting maximum current to the coil, and the retarder outputs maximum torque, and executing step (8);

[0048] Step (7): Determine whether the slip rate of each wheel reaches a threshold value: if it reaches the threshold value, adjust the current of the coil until the slip rate is lower than the threshold value; otherwise, maintain the current braking mode and execute step (9);

[0049] Step (8): Determine whether the slip ratio of each wheel reaches a threshold value: If so, maintain the pressure of the ABS solenoid valve corresponding to the tire that reaches the threshold value, and adjust the current of the coil to reduce the braking torque until the slip ratio is lower than the threshold value; otherwise, maintain the current braking mode and execute step (9);

[0050] Step (9): Determine whether the braking condition has ended. If so, turn off the combined braking control. Otherwise, execute step (1).

[0051] Furthermore, when the retarder is braking, temperature monitoring and protection are performed, specifically:

[0052] Step (1): Detecting the deceleration signal input, the working chamber temperature sensor and the water temperature sensor collect the temperature signals of the working fluid and the coolant in real time;

[0053] Step (2): Determine the relationship between the working fluid temperature and the set values ​​T1, T2 and T3:

[0054] When the working fluid temperature is less than or equal to T1, execute step (3);

[0055] When the working fluid temperature is greater than T1 and less than or equal to T2, execute step (4);

[0056] When the working fluid temperature is greater than T2 and less than T3, execute step (5);

[0057] When the working fluid temperature is greater than or equal to T3, execute step (6);

[0058] Step (3): The motor does not start and the variable frequency speed regulating water pump does not work;

[0059] Step (4): The motor controls the adaptive adjustment of the variable frequency speed regulating water pump;

[0060] Step (5): The warning light turns on, the variable frequency speed regulating water pump is controlled to operate at maximum power, and the onboard power supply is controlled to reduce the current in the coil;

[0061] Step (6): The warning light comes on and the variable frequency speed regulating water pump is controlled to work at the maximum power. Meanwhile, the clutch does not work and only the main brake works.

[0062] Furthermore, when the coil is not energized, the braking torque is provided only by the shear thickening effect of the polymer liquid, and the retarder is in a single braking condition at this time; when the coil is energized, the viscosity of the polymer liquid in the retarder is changed by controlling the current, thereby indirectly adjusting the braking torque, and the retarder is in a compound braking condition at this time.

[0063] The beneficial effects of the present invention are:

[0064] (1) The retarder of the present invention can be controlled continuously and quickly, and uses magnetorheological and shear thickening effects to perform dual field response control on the braking torque: when in a low braking intensity working condition, the coil is not energized, and only the shear thickening effect provides the braking torque, which can reduce energy consumption; when in a high braking intensity working condition, the coil is energized, and the viscosity of the magnetorheological fluid in the retarder is controlled by controlling the current, and the viscosity of the shear thickening fluid can be indirectly adjusted to provide sufficient braking torque;

[0065] (2) The polymer liquid of the present invention is made by mixing a shear thickening fluid and a magnetorheological fluid, which increases the viscosity of the working fluid. At the same time, the continuous stirring of the rotor blades can restore the polymer liquid to a uniform suspension, which can reduce the sedimentation of particles and ensure the stability of the mechanical properties of the polymer liquid;

[0066] (3) The retarder of the present invention can provide a larger braking torque than a conventional magnetorheological retarder and has high efficiency; the shear thickening fluid changes speed through the working chamber flow channel and the variable cross-section flow channel under the rotation of the rotor during braking operation. The high-speed shearing of the shear thickening fluid can provide a larger braking torque. The design of the variable cross-section flow channel can also intensify the change in the flow rate of the polymer liquid, thereby ensuring a larger braking torque;

[0067] (4) The retarder of the present invention has good heat dissipation performance. By directly dissipating heat to the core area of ​​the retarder working chamber and the heat dissipation effect of the cooling fan without the need for additional energy supply, the retarder is ensured to have good heat dissipation performance;

[0068] (5) The control method of the retarder can control the retarder compound braking, the main brake and the retarder combined braking and the working fluid temperature monitoring and protection, make full use of the structural characteristics of the retarder to perform retarding braking, and ensure the working stability of the retarder. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 This is a schematic diagram of the control principle of the shear thickening magnetorheological fluid composite brake retarder of the present invention;

[0070] Figure 2 Schematic diagram of the structure of the shear thickening magnetorheological fluid composite brake retarder of the present invention;

[0071] Figure 3 yes Figure 2 AA cross-section of

[0072] Figure 4 Schematic diagram of the internal flow of the coolant according to the present invention;

[0073] Figure 5 It is a schematic structural diagram of the rotor and the hollow input shaft of the retarder according to the present invention;

[0074] Figure 6 This is a control flow chart of the shear thickening magnetorheological fluid composite brake retarder of the present invention;

[0075] Figure 7 This is a flow chart of the combined control of the shear thickening magnetorheological fluid composite brake retarder and the main brake according to the present invention;

[0076] Figure 8 This is a flow chart of the temperature monitoring and protection function control of the shear thickening magnetorheological fluid composite brake retarder of the present invention;

[0077] In the figure: 1- transmission shaft; 2- gear train; 3- clutch; 4- rotor; 4-1- left connecting circular plate; 4-2- right connecting circular plate; 4-3- fan blade; 5- hollow input shaft of retarder; 6- cooling fan; 7- housing; 7-1- left housing; 7-2- right housing; 8- working chamber; 9- polymer liquid; 10- working chamber flow channel; 11- variable cross-section flow channel; 12- cooling water flow channel; 13- liquid outlet; 14- sealing injection Liquid plug; 15-coil; 16-magnetic isolation ring; 17-left bearing; 18-right bearing; 19-large sealing ring; 20-speed increasing gear pair; 21-working chamber temperature sensor; 22-water temperature sensor; 23-variable frequency speed regulating water pump; 24-radiator; 25-cooling water pipeline; 26-liquid inlet; 27-motor; 28-retarder controller; 29-on-board power supply; 30-signal line; 32-vehicle controller; 33-sealing ring. DETAILED DESCRIPTION

[0078] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited thereto.

[0079] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "lower", "vertical", "horizontal", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the present invention, unless otherwise clearly specified and limited, the terms "install", "connect", "connect", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediate medium, or the internal connection of two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0080] like Figure 1 、 2The shear-thickening magnetorheological fluid composite brake retarder of the present invention includes a retarder body, an electronic control system, and a heat dissipation system. The retarder can be deployed at the transmission output, transmission input, or rear axle input, depending on the needs. This embodiment describes the retarder as being deployed at the transmission output.

[0081] like Figure 2 As shown, the retarder body includes a rotor 4, a housing 7, a hollow retarder input shaft 5, a working chamber 8, a polymer liquid 9, a coil 15, and a magnetic isolation ring 16. The housing 7 is divided into two parts: a left housing 7-1 and a right housing 7-2, which are sealed by a large sealing ring 19. The left housing 7-1 has a liquid outlet 13 at its upper end. The rotor 4 is located within the housing 7, forming a working chamber 8 with the housing 7. The working chamber 8 is filled with a polymer liquid 9, which serves as the working fluid. The housing 7 is provided with a sealed liquid injection plug 14, which is connected to the working chamber for injection of the polymer liquid 9. The polymer liquid 9 is composed of polyethylene glycol PEG200 and silicon dioxide as a matrix, with carbonyl iron powder dissolved therein. The carbonyl iron powder is of micro-nano grade. The operating temperature of the polymer liquid 9 is between -40°C and 160°C. The hollow input shaft 5 of the retarder passes through the housing 7 and the rotor 4 in sequence, and a sealing ring 33 is provided between the hollow input shaft 5 of the retarder and the housing 7; the rotor 4 is fixedly connected to the hollow input shaft 5 of the retarder, the left side of the hollow input shaft 5 of the retarder passes through the left housing 7-1 and is rotatably connected to the left housing (in this embodiment, the left bearing 17 is used for connection), and the right side passes through the right housing 7-2 and is rotatably connected to the right housing (in this embodiment, the right bearing 18 is used for connection). The left end of the hollow input shaft 5 of the retarder is connected to the clutch 3 through the speed-increasing gear pair 20, and the clutch 3 is connected to the transmission shaft 1 through the gear system 2. The power is transmitted to the speed-increasing gear pair 20 through the transmission shaft 1 and the clutch 3, and the hollow input shaft 5 of the retarder is driven to rotate by the speed-increasing gear pair 20. As shown Figure 2 As shown, coil 15 is embedded in housing 7 and arranged axially along the outer circumference of rotor 4. A magnetic isolation ring 16 is provided on the outer edge of coil 15 to confine the magnetic field within working chamber 8. Coil 15 is powered by an onboard power supply 29. When retarder controller 28 outputs a power-on command for coil 15, onboard power supply 29 supplies power to coil 15, causing it to establish a magnetic field within working chamber 8.

[0082] like Figure 2 、 3As shown in Figure 5, the rotor 4 includes a left connecting circular plate 4-1, a right connecting circular plate 4-2 and blades 4-3, and the left connecting circular plate 4-1, the right connecting circular plate 4-2 and the blades 4-3 are all fixed on the hollow input shaft 5 of the retarder, and a plurality of blades 4-3 are evenly arranged between the left connecting circular plate 4-1 and the right connecting circular plate 4-2, and the number of blades 4-3 is at least 4; a working chamber circulation channel 10 is left between the outer periphery of the blade 4-3 and the inner wall of the working chamber 8, and two variable-section circulation channels 11 are evenly opened on the blade 4-3 and penetrate the body of the blade 4-3, and the cross-sectional area of ​​the variable-section circulation channel 11 changes from large to small from one side of the rotation direction of the rotor 4; a cooling water flow channel 12 is opened inside the outermost part of the blade 4-3, inside the hollow input shaft 5 of the retarder and inside the shell 7, and the cooling water flow channel 12 inside the hollow input shaft 5 of the retarder is connected to the cooling water flow channel 12 inside the outermost part of the blade 4-3 and the right shell 7-2.

[0083] like Figure 1 As shown, the electronic control system includes a vehicle controller 32, a retarder controller 28, a working chamber temperature sensor 21, and a water temperature sensor 22. The retarder controller 28 is connected to the motor 27 and the variable frequency speed regulating water pump 23 in sequence via a signal line 30. By receiving instructions from the vehicle controller 32, the variable frequency speed regulating water pump 23 is controlled to open and close and adjust the flow rate. The vehicle controller 32, the retarder controller 28, and the vehicle power supply 29 are connected via a signal line 30. The vehicle controller 32 determines whether it is necessary to energize the coil 15. If there is a power-on requirement, the retarder controller 28 sends a corresponding instruction. Then, the retarder controller 28 controls the current output by the vehicle power supply 29 to the coil 15 (the control of the current is a prior art), thereby achieving a control effect of controlling the magnetic field strength in the working chamber 8. A working chamber temperature sensor 21 is set in the working chamber 8, and the working chamber temperature sensor 21 is connected to the vehicle controller 32. The working chamber temperature sensor 21 is used to detect the temperature of the working fluid. The water temperature sensor 22 is arranged beside the liquid outlet 13 and is connected to the vehicle controller 32 for monitoring the temperature of the coolant flowing out of the retarder body to ensure that it is at a normal temperature and to ensure good heat dissipation performance of the radiator 24.

[0084] like Figure 1 As shown, the cooling system includes a radiator 24, a cooling fan 6, a variable frequency speed regulating water pump 23, an electric motor 27, a cooling water pipeline 25 and an internal cooling water flow channel 12, wherein the radiator 24 is fixed on the housing 7, and the cooling fan 6 is coaxially arranged on the hollow input shaft 5 of the retarder to drive the air flow to dissipate heat from the radiator 24. Figure 3 As shown, the internal cooling water channel 12 is arranged inside the retarder hollow input shaft 5, the rotor 4, and the housing 7, and is connected to the cooling water pipeline 25 through the liquid inlet 26 provided on the retarder hollow input shaft 5 and the liquid outlet 13 on the housing 7 to form a closed loop. Figure 4 and Figure 5As shown, the coolant flows through the cooling water channel 12 in the following manner: the coolant flows from the hollow portion of the retarder hollow input shaft 5, sequentially through the hollow portion of the left connecting circular plate 4-1, the hollow portion of the fan blade 4-3, the hollow portion of the right connecting circular plate 4-2, to the hollow portion of the right housing 7-2, then flows back to the hollow portion of the left housing 7-1, and finally reaches the liquid outlet 13. The liquid inlet 26 is connected to the variable frequency speed regulating water pump 23, the radiator 24, and the liquid outlet 13 in sequence through the cooling water pipeline 25. The variable frequency speed regulating water pump 23 is arranged on the cooling water pipeline 25 and is located near the liquid inlet 26. Its function is to pump the cooled coolant in the radiator 24 into the cooling water channel 12 through the liquid inlet 26, so that the cooling water circulates in the cooling water pipeline 25, the cooling water channel 12, and the radiator 24, thereby cooling the working fluid in the core area of ​​the working chamber 8. The motor 27 is connected to the retarder controller 28 and the variable frequency speed regulating water pump 23 via a signal line 30 to drive the variable frequency speed regulating water pump 23 to operate.

[0085] The working principle of a shear-thickening magnetorheological fluid composite brake retarder is as follows: when the retarder is working, the clutch 3 engages the drive shaft 1 with the retarder hollow input shaft 5, and the drive shaft 1 drives the retarder hollow input shaft 5, the cooling fan 6 and the rotor 4 to work. The rotation of the rotor 4 causes a shear-thickening effect, thereby generating a braking torque, which is fed back from the rotor 4 to the drive shaft 1, thereby providing a braking torque to the vehicle; when heat dissipation is required, the coolant is pumped from the radiator 24 through the cooling water pipe 25 into the retarder body by the variable frequency speed regulating water pump 23, thereby taking away the heat from the core area of ​​the retarder, reducing its temperature, and finally returning to the radiator 24 to complete the circulation cooling.

[0086] A shear-thickening magnetorheological fluid composite brake retarder can achieve single braking conditions and composite braking conditions: when the coil 15 is not energized, the braking torque is provided only by the shear-thickening effect of the polymer liquid 9, which is a single braking condition; when the coil 15 is energized, the viscosity of the polymer liquid 9 in the retarder is changed by controlling the current, and the braking torque is indirectly adjusted, which is a composite braking condition.

[0087] like Figure 6 As shown, the present invention provides a control method for a shear thickening magnetorheological fluid composite brake retarder, which specifically includes the following steps:

[0088] Step (1): The vehicle controller 32 determines whether a deceleration signal is input (the deceleration signal is input by the driver):

[0089] If there is a signal input, execute step (2);

[0090] If there is no signal input, the retarder controller 28 system is reset, the vehicle runs normally, and the vehicle controller 32 controls the clutch 3 to not work, so that the retarder has no effect on the normal driving of the vehicle;

[0091] Step (2): The vehicle controller 32 determines whether a composite braking signal is input (a deceleration signal is input by the driver):

[0092] If there is a signal input, execute step (3);

[0093] If there is no signal input, the coil 15 is not energized, and the retarder relies on the braking force generated by the high-speed shearing of the polymer liquid 9 (shear thickening liquid) to perform a single braking operation, at which time no electrical energy is consumed, and step (4) is executed;

[0094] Step (3): The vehicle controller 32 determines whether a constant speed signal is input (the deceleration signal is input by the driver):

[0095] If a constant speed signal is input, the deceleration controller 28 sends a power transmission instruction to the vehicle power supply 29 to energize the coil 15. The vehicle controller 32 collects the real-time vehicle speed when the coil 15 starts working through the vehicle speed sensor, sets it as the set value, and executes step (5);

[0096] If there is no constant speed signal input, the coil 15 is energized, and the vehicle controller 32 collects the vehicle speed signal and the wheel speed signal (collected by the wheel speed sensor) and calculates the slip rate of each wheel (the calculation process is the existing technology) to determine whether the slip rate is greater than the set value: if the slip rate is greater than the set value, the retarder controller 28 adjusts the current of the coil 15 to achieve the purpose of adjusting the braking torque until the slip rate is less than the set value (the adjustment process is the existing technology); otherwise, the current size of the coil 15 is maintained and step (1) is executed;

[0097] Step (4): The vehicle controller 32 determines whether the current braking torque meets the slow braking requirement:

[0098] If the deceleration braking requirement is met, the current single braking is maintained, and it is determined whether the deceleration condition has ended. If so, step (6) is executed; if not, a single braking is performed by relying on the braking force generated by the high-speed shearing of the polymer liquid 9, and it is determined whether the deceleration condition has ended, until the deceleration condition has ended;

[0099] If the deceleration braking requirement is not met, then execute step (3);

[0100] Step (5): The vehicle controller 32 continues to collect the real-time vehicle speed through the vehicle speed sensor and determines whether the real-time vehicle speed is equal to the set value:

[0101] If the real-time vehicle speed is equal to the set value, it is determined whether the deceleration condition is ended. If it is ended, step (6) is executed. Otherwise, the real-time vehicle speed is continuously collected, and it is determined whether the real-time vehicle speed is equal to the set value, and the corresponding steps are executed.

[0102] If the real-time vehicle speed is not equal to the set value, it is determined whether the deceleration condition is ended. If it is ended, step (6) is executed. Otherwise, the current of coil 15 is adjusted, the real-time vehicle speed is continued to be collected, and it is determined whether the real-time vehicle speed is equal to the set value, and the corresponding steps are executed.

[0103] Step (6) exits the braking state and the retarder controller 28 system is reset.

[0104] In order to adapt to various working conditions and protect the retarder and the vehicle main brake, the retarder and the main brake can be braked in combination, such as Figure 7 As shown, the combined braking control method of the retarder and the vehicle main brake includes the following steps:

[0105] Step (1): The driver turns on the combined braking control function, and the vehicle controller 32 collects the vehicle speed signal and each wheel speed signal and calculates the slip rate of each wheel, and then determines whether the real-time vehicle speed is greater than the minimum set value V1:

[0106] If the real-time vehicle speed is greater than the minimum set value V1, then execute step (2);

[0107] Otherwise, combined braking control is performed. At this time, the retarder is turned on (achieved by controlling the clutch 3 by the vehicle controller 32), but the coil 15 is not energized. The retarder enters a single braking state, and the main brake manually adjusts its braking force according to demand, and executes step (3);

[0108] Step (2): The vehicle controller 32 determines the relationship between the real-time vehicle speed and the set values ​​V2 and V3:

[0109] If the real-time vehicle speed is less than or equal to V2, then execute step (4);

[0110] If the real-time vehicle speed is greater than V2 but less than V3, then execute step (5);

[0111] If the real-time vehicle speed is greater than or equal to V3, then execute step (6);

[0112] Step (3): The vehicle controller 32 determines whether the slip ratio of each wheel reaches a threshold value. If the slip ratio reaches the threshold value, the vehicle triggers the ABS anti-lock braking system, and the ABS anti-lock braking system intervenes to ensure that the slip ratio of each wheel is lower than the threshold value (this process is conventional technology); otherwise, the current braking mode is maintained and step (9) is executed.

[0113] Step (4): The main brake does not intervene in the operation and does not perform combined braking control, wherein the retarder performs compound braking, the coil 15 is energized, and the current of the coil 15 is adjusted according to the braking demand to perform stepless adjustment of the braking force, and step (7) is executed;

[0114] Step (5): The vehicle performs combined braking control, and the retarder performs compound braking at the same time. The coil 15 is energized, and the braking force is steplessly adjusted according to the braking demand. The main brake adjusts the braking force for the person according to the demand, and then executes step (8);

[0115] Step (6): The vehicle performs combined braking control, and the retarder performs compound braking at the same time. The vehicle power supply 29 inputs the maximum current to the coil 15, the retarder outputs the maximum torque, and step (8) is executed;

[0116] Step (7): The vehicle controller 32 determines whether the slip rate of each wheel reaches a threshold value. If so, the current of the coil 15 is adjusted until the slip rate is lower than the threshold value. Otherwise, the current braking mode is maintained and step (9) is executed.

[0117] Step (8): The vehicle controller 32 determines whether the slip ratio of each wheel reaches the threshold value. If so, the ABS solenoid valve corresponding to the tire that reaches the threshold value is maintained at a pressure, and the current of the coil 15 is adjusted to reduce the braking torque until the slip ratio is lower than the threshold value. Otherwise, the current braking mode is maintained and step (9) is executed.

[0118] Step (9): The vehicle controller 32 determines whether the braking condition has ended. If so, the combined braking control function is turned off. Otherwise, step (1) is executed.

[0119] When the retarder is braking, the temperature monitoring and protection functions are turned on, such as Figure 8 As shown, the control method of the retarder temperature monitoring and protection function includes the following steps:

[0120] Step (1): upon detecting a deceleration signal input, the vehicle controller 32 collects temperature signals of the working fluid and the coolant in real time through the working chamber temperature sensor 21 and the water temperature sensor 22;

[0121] Step (2): The vehicle controller 32 determines the relationship between the working fluid temperature and the set values ​​T1, T2 and T3:

[0122] When the working fluid temperature is less than or equal to T1, execute step (3);

[0123] When the working fluid temperature is greater than T1 and less than or equal to T2, execute step (4);

[0124] When the working fluid temperature is greater than T2 and less than T3, execute step (5);

[0125] When the working fluid temperature is greater than or equal to T3, execute step (6);

[0126] Step (3): the motor 27 is not turned on and the variable frequency speed regulating water pump 23 does not work;

[0127] Step (4): the vehicle controller 32 sends a command to the retarder controller 28, and the motor 27 controls the variable frequency speed regulating water pump 23 to perform adaptive adjustment (the adaptive adjustment process is a prior art);

[0128] Step (5): The vehicle controller 32 issues a command to turn on the warning light (wherein the warning light is set in the control panel of the cab), and at the same time controls the variable frequency speed regulating water pump 23 to work at maximum power, and controls the vehicle power supply 29 through the retarder controller 28 to reduce the current in the coil 15;

[0129] Step (6): The vehicle controller 32 issues a command to turn on the warning light, and at the same time controls the variable frequency speed regulating water pump 23 to operate at maximum power, while making the clutch 3 not operate, and only the main brake operates.

[0130] The embodiments described are preferred implementations of the present invention, but the present invention is not limited to the above implementations. Any obvious improvements, substitutions or modifications that can be made by those skilled in the art without departing from the essence of the present invention are within the scope of protection of the present invention.

Claims

1. A shear thickening magnetorheological fluid composite brake retarder, characterized in that: include: The retarder body comprises a rotor (4), a housing (7), a retarder hollow input shaft (5) and a coil (15); the rotor (4) is located inside the housing (7) and forms a working chamber (8) with the housing (7), wherein the working chamber (8) is filled with a polymer liquid (9); the retarder hollow input shaft (5) sequentially penetrates the housing (7) and the rotor (4), and the rotor (4) is fixedly connected to the retarder hollow input shaft (5), and the housing (7) is rotatably connected to the retarder hollow input shaft (5); The coil (15) is embedded in the housing (7) and arranged axially along the outer circumference of the rotor (4); the coil (15) is powered by an onboard power supply (29); The retarder hollow input shaft (5) is connected to the transmission shaft (1) via a clutch (3); The rotor (4) comprises two connecting circular plates and a plurality of blades (4-3) uniformly arranged between the two connecting circular plates; a working chamber circulation channel (10) is left between the outer periphery of the blade (4-3) and the inner side wall of the working chamber (8); two variable cross-section circulation channels (11) are uniformly opened on the blade (4-3) and penetrate the main body of the blade (4-3); the cross-sectional area of ​​the variable cross-section circulation channel (11) decreases from large to small on one side in the rotation direction of the rotor (4).

2. The shear thickening magnetorheological fluid composite brake retarder according to claim 1, characterized in that: Also includes: The heat dissipation system includes a radiator (24), a variable frequency speed regulating water pump (23), an electric motor (27) and a cooling water flow channel (12); the cooling water flow channel (12) is provided inside the outermost part of the fan blade (4-3), inside the hollow input shaft (5) of the retarder and inside the housing (7); the cooling water flow channel (12) inside the hollow input shaft (5) of the retarder is connected to the cooling water flow channel (12) inside the outermost part of the fan blade (4-3) and inside the right housing; The variable frequency speed regulating water pump (23), the liquid inlet (26) on the retarder hollow input shaft (5), the cooling water flow channel (12), the liquid outlet (13) on the housing (7) and the radiator (24) are connected through pipelines; The electric motor (27) is electrically connected to the variable frequency speed regulating water pump (23).

3. The shear thickening magnetorheological fluid composite brake retarder according to claim 2, characterized in that: Also includes: An electronic control system comprises a vehicle controller (32), a retarder controller (28), a working chamber temperature sensor (21) and a water temperature sensor (22), wherein the working chamber temperature sensor (21) is arranged in the working chamber (8), and the water temperature sensor (22) is arranged next to the liquid outlet (13). Information collected by the working chamber temperature sensor (21) and the water temperature sensor (22) is transmitted to the vehicle controller (32), and the retarder controller (28) is connected to the motor (27), the vehicle power supply (29) and the vehicle controller (32) respectively.

4. The shear thickening magnetorheological fluid composite brake retarder according to claim 2, characterized in that: The heat dissipation system further comprises a heat dissipation fan (6), and the heat dissipation fan (6) is coaxially arranged on the hollow input shaft (5) of the retarder.

5. The shear thickening magnetorheological fluid composite brake retarder according to claim 1, characterized in that: A magnetic isolation ring (16) is provided on the outer edge of the coil (15).

6. A control method for a shear thickening magnetorheological fluid composite brake retarder according to any one of claims 1 to 5, characterized in that: Step (1): Determine whether there is a deceleration signal input: If there is a signal input, execute step (2); If there is no signal input, the vehicle runs normally and the clutch (3) does not work; Step (2): Determine whether there is a composite brake signal input: If there is a signal input, execute step (3); If there is no signal input, the coil (15) is not energized, the retarder performs a single brake, and step (4) is executed; Step (3): Determine whether there is a constant speed signal input: If a constant speed signal is input, the coil (15) is energized, the real-time vehicle speed when the coil (15) starts working is set as the set value, and step (5) is executed; If there is no constant speed signal input, the coil (15) is energized to determine whether the slip ratio is greater than the set value: if the slip ratio is greater than the set value, the current of the coil (15) is adjusted to adjust the braking torque until the slip ratio is less than the set value; otherwise, the current of the coil (15) is maintained and step (1) is executed; Step (4): Determine whether the current braking torque meets the slow braking requirement: If the deceleration braking requirement is met, the current single braking is maintained and it is determined whether the deceleration condition has ended. If so, step (6) is executed. If not, the retarder performs a single braking and determines whether the deceleration condition has ended until the deceleration condition has ended. If the deceleration braking requirement is not met, then execute step (3); Step (5): Continue to collect real-time vehicle speed and determine whether the real-time vehicle speed is equal to the set value: If the real-time vehicle speed is equal to the set value, determine whether the deceleration condition is ended: if it is ended, execute step (6); otherwise, continue to collect the real-time vehicle speed and determine whether the real-time vehicle speed is equal to the set value; If the real-time vehicle speed is not equal to the set value, determine whether the deceleration condition is ended: if it is ended, execute step (6); otherwise, adjust the current of coil (15), continue to collect the real-time vehicle speed and determine whether the real-time vehicle speed is equal to the set value; Step (6) exiting the braking state; The retarder can perform joint braking control with the vehicle main brake, specifically: Step (1): Determine whether the real-time vehicle speed is greater than the minimum set value V1: If the real-time vehicle speed is greater than the minimum set value V1, then execute step (2); Otherwise, combined braking control is performed, in which the retarder performs single braking, and the main brake manually adjusts its braking force according to demand, and executes step (3); Step (2): Determine the relationship between the real-time vehicle speed and the set values ​​V2 and V3: If the real-time vehicle speed is less than or equal to V2, then execute step (4); If the real-time vehicle speed is greater than V2 but less than V3, then execute step (5); If the real-time vehicle speed is greater than or equal to V3, then execute step (6); Step (3): Determine whether the slip rate of each wheel reaches a threshold value: If the slip rate reaches the threshold value, the ABS anti-lock braking system is triggered to intervene to ensure that the slip rate of each wheel is lower than the threshold value; otherwise, the current braking mode is maintained and step (9) is executed; Step (4): The main brake does not intervene in the operation, the retarder performs compound braking, and the current of the coil (15) is adjusted according to the braking demand to perform stepless adjustment on the braking force, and step (7) is executed; Step (5): The vehicle performs combined braking control, and the retarder performs compound braking at the same time. The current of the coil (15) is adjusted according to the braking demand to perform stepless adjustment of the braking force. The main brake adjusts its braking force for the person according to the demand, and then executes step (8); Step (6): The vehicle performs combined braking control, and the retarder performs compound braking at the same time, inputting maximum current to the coil (15), the retarder outputs maximum torque, and executing step (8); Step (7): Determine whether the slip rate of each wheel reaches a threshold value: if it reaches the threshold value, adjust the current of the coil (15) until the slip rate is lower than the threshold value; otherwise, maintain the current braking mode and execute step (9); Step (8): Determine whether the slip ratio of each wheel reaches a threshold value: If the threshold value is reached, the ABS solenoid valve corresponding to the tire that reaches the threshold value is maintained at a pressure, and the current of the coil (15) is adjusted at the same time to reduce the braking torque until the slip ratio is lower than the threshold value; otherwise, the current braking mode is maintained and step (9) is executed; Step (9): Determine whether the braking condition has ended. If so, turn off the combined braking control. Otherwise, execute step (1).

7. The control method according to claim 6, characterized in that: When the retarder brakes, temperature monitoring and protection are performed, specifically: Step (1): upon detecting a deceleration signal input, the working chamber temperature sensor (21) and the water temperature sensor (22) collect temperature signals of the working fluid and the cooling fluid in real time; Step (2): Determine the relationship between the working fluid temperature and the set values ​​T1, T2 and T3: When the working fluid temperature is less than or equal to T1, execute step (3); When the working fluid temperature is greater than T1 and less than or equal to T2, execute step (4); When the working fluid temperature is greater than T2 and less than T3, execute step (5); When the working fluid temperature is greater than or equal to T3, execute step (6); Step (3): the motor (27) is not turned on and the variable frequency speed regulating water pump (23) does not work; Step (4): The motor (27) controls the variable frequency speed regulating water pump (23) to perform adaptive regulation operation; Step (5): The warning light turns on, the variable frequency speed regulating water pump (23) is controlled to operate at maximum power, and the vehicle power supply (29) is controlled to reduce the current in the coil (15); Step (6): The warning light comes on, and the variable frequency speed regulating water pump (23) is controlled to operate at maximum power. Meanwhile, the clutch (3) does not operate, and only the main brake operates.

8. The control method according to claim 7, characterized in that: When the coil (15) is not energized, the braking torque is provided only by the shear thickening effect of the polymer liquid (9), and the retarder is in a single braking condition at this time; when the coil (15) is energized, the viscosity of the polymer liquid (9) in the retarder is changed by controlling the current, and the braking torque is indirectly adjusted at this time, and the retarder is in a compound braking condition.

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