A method, system and electronic device for controlling the braking torque of a retarder in a limit operating condition

Abstract

The application discloses a retarder limit working condition braking torque control method and system and electronic equipment, and belongs to the technical field of vehicle control. The application collects multi-dimensional working condition signals, constructs a layered torque constraint logic, and the logic execution priority is lower than the highest level fault protection logic of the whole vehicle. The low-temperature working condition is controlled and managed according to the gradient temperature threshold, and the upper limit of the braking torque is dynamically corrected in combination with the oil temperature rise rate. The high-temperature working condition relies on the joint prediction of the thermal load of multiple parameters, and the braking torque is lowered in advance through multi-level coefficient superposition correction. The target torque obtained through the constraint operation is converted into an oil pressure signal to drive the proportional valve to output the braking force. After the working condition risk condition is removed, a gradual transition strategy is adopted to restore to the original request torque of the driver. The application can accurately constrain the output torque of the retarder under high and low temperature limit working conditions, avoid overheating failure risk in advance, the torque recovery process is smooth and impact-free, and the running safety and driving comfort of the retarder are improved.

Description

Technical Field

[0001] This application relates to the field of vehicle control technology, and in particular to a method for controlling the braking torque of a retarder under extreme operating conditions, a control system for the braking torque of a retarder under extreme operating conditions, electronic equipment, and storage medium. Background Technology

[0002] As a core auxiliary braking device for heavy-duty commercial vehicles, hydraulic retarder effectively shares the workload of the main service brake due to its advantages of smooth braking, no wear, and long service life. It avoids problems such as heat fade and brake failure caused by long-term continuous braking, and significantly improves the driving safety of vehicles in conditions such as long-distance downhill driving and continuous braking. It is now widely installed in various heavy trucks, buses and other commercial vehicles, and has become an important part of the commercial vehicle braking system.

[0003] Heavy-duty commercial vehicles operate in complex and varied environments, often requiring routine operation in extreme conditions such as high and low temperatures. The performance of hydraulic retarders is highly dependent on the state of the working fluid and ambient temperature. Extreme temperature conditions can easily lead to abnormal retarder operating parameters and unstable braking performance, severely impacting the reliability of the braking system and the overall vehicle safety. Currently, the industry's control solutions and protection strategies for hydraulic retarders still have significant technical shortcomings, failing to fully adapt to complex high and low temperature extreme conditions. Their overall performance and adaptability to operating conditions need further improvement.

[0004] In terms of high-temperature operating condition control, existing mainstream control solutions focus on high-temperature overload protection, generally adopting a passive protection control mode triggered by a single oil temperature threshold. This control method can only achieve passive protection by gradually reducing braking torque after the retarder oil temperature exceeds the preset threshold. The protection action has a significant lag and cannot predict the oil temperature rise trend in advance to avoid the risk of retarder thermal overload. At the same time, the existing control logic is one-dimensional and does not comprehensively integrate key operating condition parameters such as oil temperature change rate, road slope, vehicle speed, vehicle wind cooling conditions, and continuous braking duration. It cannot accurately match the heat dissipation and heating characteristics of different complex driving conditions, resulting in extremely poor adaptability. During the high-temperature torque reduction protection process, the braking torque is prone to sudden drop and braking force change, directly causing vehicle jerking and reduced braking smoothness. This not only affects driving comfort but also causes sudden changes in the vehicle's braking state, creating potential driving safety hazards.

[0005] In terms of low-temperature control, the existing technology system has significant protection deficiencies, and a targeted low-temperature adaptation and protection strategy has not yet been formed. Under extreme low-temperature environments, the viscosity of the working oil inside the retarder will increase sharply and its fluidity will deteriorate significantly. If braking torque is applied directly according to conventional control logic, the high-viscosity oil will generate severe internal shearing, producing a large amount of shear heat in a short time, causing a sudden change in the internal temperature of the retarder. At the same time, the high-viscosity oil will exert high-intensity impact loads on core components such as valve bodies and impellers. Long-term low-temperature impact operation will accelerate the wear and aging of components, significantly shorten the overall service life of the hydraulic retarder, and reduce the reliability of equipment operation.

[0006] In addition, existing traditional control schemes generally do not have smooth transition control logic for temperature condition switching. At the critical temperature nodes of high and low temperatures, the braking torque is prone to frequent fluctuations and jumps, making it impossible to achieve a smooth connection of braking force, which further deteriorates the driving experience and the vehicle's braking stability.

[0007] In summary, traditional hydraulic retarder control methods cannot meet the adaptability requirements of extreme operating conditions at both high and low temperatures, and cannot simultaneously satisfy the multiple technical requirements of long-term equipment reliability, braking smoothness, and vehicle driving safety. They have significant technical defects, and there is an urgent need to develop an intelligent control strategy for hydraulic retarders that can adapt to extreme operating conditions at both high and low temperatures. Summary of the Invention

[0008] In view of this, the purpose of this invention is to provide a method for controlling the braking torque of a retarder under extreme operating conditions, a control system for the braking torque of a retarder under extreme operating conditions, electronic equipment and storage medium, aiming to solve the technical problems of existing hydraulic retarder control schemes that rely solely on passive protection based on oil temperature, lack dedicated low-temperature control, and fail to combine multiple parameters to predict thermal load, which easily leads to component damage, sudden drops in braking force, and inability to avoid thermal overload in advance under extreme high and low temperature conditions.

[0009] This invention provides the following solution: According to one aspect of the present invention, a method for controlling the braking torque of a retarder under extreme operating conditions is provided, comprising the following steps: Collect multi-dimensional operating condition signals; The multi-dimensional operating condition signals include: oil temperature rise rate; Based on the collected multi-dimensional operating condition signals, a hierarchical torque constraint logic is established: When the real-time oil temperature of the retarder is lower than the preset low temperature threshold, the upper limit of the output torque is set according to the oil temperature gradient, and the torque limit amplitude is dynamically adjusted according to the oil temperature rise rate; when the oil temperature is lower than the preset extremely low temperature threshold, active preheating control is activated and the maximum output torque is constrained; a low temperature constraint target torque is generated. When the preset thermal overload risk condition is detected, the graded torque reduction control is activated, and the torque reduction magnitude is superimposed and corrected in combination with the vehicle driving status and the vehicle's heat dissipation capacity; a high-temperature correction target torque is generated. The low-temperature constraint target torque and the high-temperature correction target torque are converted into oil pressure signals to control the proportional valve to output braking force. Once the operating condition risk is eliminated, a gradual transition strategy is adopted to restore the original requested torque. The execution priority of the layered torque constraint logic is lower than that of the highest-level vehicle fault protection logic. Furthermore, the oil temperature gradient setting of the output torque upper limit includes: Three-level progressive control logic: extreme cold preheating protection, wide temperature range linear torque release, and low temperature temperature rise rate dynamic torque limiting; The extreme cold preheating protection outputs low oil pressure for preheating and limits the maximum braking torque when the oil temperature is below the extreme cold threshold. The protection is deactivated when the oil temperature rises to the extreme cold threshold. The wide-temperature-range linear torque release means that within the temperature range from the extreme cold threshold to the normal temperature boundary, the upper limit of the allowable torque increases linearly with the increase of oil temperature. The low-temperature temperature rise rate dynamic torque limiting: when the oil temperature is lower than the normal temperature boundary temperature, the linear torque limiting coefficient is set in segments according to the oil temperature rise rate. The faster the temperature rise, the stronger the torque output limitation. The final output braking torque under low-temperature conditions is calculated by coupling the upper limit of torque corresponding to the temperature range and the torque limiting coefficient corresponding to the temperature rise rate.

[0010] Furthermore, the pre-set thermal overload risk conditions include: When the oil temperature rise rate exceeds a preset threshold, when the road gradient is greater than a preset threshold and exceeds a preset time, and when the current vehicle speed is lower than a preset threshold; Pre-dip torque is initiated when any condition is met; Configure the corresponding basic moment reduction coefficient based on the combination type that triggers the risk; the more risks are combined, the greater the basic moment reduction will be.

[0011] Furthermore, the method of combining vehicle driving conditions and overall vehicle cooling capacity to adjust the torque reduction also includes: The first level is low-speed heat dissipation correction, which further reduces the basic output torque when the vehicle is traveling below the low-speed threshold. The second level is the vehicle cooling system classification correction, which classifies the heat dissipation level according to the engine coolant temperature. The worse the cooling conditions, the greater the torque reduction.

[0012] Furthermore, the braking force output of the proportional valve is achieved by: matching the corresponding target oil pressure according to the final constraint torque by looking up a table, and continuously adjusting the duty cycle of the proportional valve.

[0013] Furthermore, the gradual transition recovery strategy is as follows: after leaving the high and low temperature risk conditions, the oil pressure is gradually increased after a fixed transition time is set, and the braking force is smoothly restored to the original torque requested by the driver.

[0014] Furthermore, generating the cryogenic constraint target torque includes: First, obtain the torque upper limit constraint value corresponding to the temperature through the oil temperature range, then obtain the dynamic torque limiting coefficient by combining the real-time oil temperature rise rate, and multiply the torque upper limit constraint value with the dynamic torque limiting coefficient to obtain the final allowable output braking torque under low temperature conditions. The dynamic torque limiting coefficient changes linearly with the temperature rise rate in a piecewise manner: there is no torque limiting when the temperature rise rate is below the low-speed temperature rise threshold; when the temperature rise rate is in the temperature rise threshold range, the torque limiting coefficient decreases linearly with the increase of the temperature rise rate; after the temperature rise rate exceeds the high-speed temperature rise threshold, the torque limiting coefficient remains at a fixed minimum value.

[0015] According to two aspects of the present invention, a retarder braking torque control system under extreme operating conditions is provided, comprising: a signal acquisition module, a torque constraint calculation module, and a hydraulic output control module; The signal acquisition module is used to acquire multi-dimensional operating condition signals, including: retarder oil temperature, oil temperature rise rate, vehicle speed, and road gradient. The torque constraint calculation module is used to establish hierarchical torque constraint logic, which includes a low-temperature operating condition control branch and a high-temperature operating condition control branch. The low-temperature operating condition control branch is used to set the upper limit of output torque according to the oil temperature gradient when it is determined that the real-time oil temperature of the retarder is lower than the preset low-temperature threshold, and to dynamically adjust the torque limit amplitude according to the oil temperature rise rate; when it is determined that the oil temperature is lower than the preset extreme low temperature threshold, it generates an active preheating control command and constrains the maximum output torque, and outputs the low-temperature constraint target torque. The high-temperature operating condition control branch is used to generate graded torque reduction control commands when the preset thermal overload risk conditions are met, and to combine the vehicle driving status and the vehicle's heat dissipation capacity to superimpose and correct the torque reduction magnitude, and output the high-temperature correction target torque. The hydraulic output control module is used to receive the low-temperature constraint target torque and the high-temperature correction target torque, convert them into hydraulic signals and output them to the proportional valve to control the braking force output; It is also used to control the output torque to return to the original requested torque according to the gradual transition strategy after the working condition risk is eliminated.

[0016] According to three aspects of the present invention, an electronic device is provided, comprising: a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other via the communication bus; The memory stores a computer program, which, when executed by a processor, causes the processor to perform steps of a retarder limit condition braking torque control method.

[0017] According to four aspects of the present invention, a computer-readable storage medium is provided that stores a computer program executable by an electronic device, which, when run on the electronic device, causes the electronic device to perform the steps of a retarder limit condition braking torque control method.

[0018] Compared with the prior art, the present invention has the following advantages: To address the shear shock and instantaneous overheating damage caused by the rapid increase in oil viscosity at low temperatures, this invention employs a three-stage low-temperature control mechanism: when the oil temperature is below -30℃, low-pressure preheating is initiated and the maximum output torque is forcibly limited to no more than 50% of the rated value, preventing cold oil from directly bearing a large load impact; in the range of -30℃ to 0℃, a linear interpolation torque limit MAP is adopted, gradually releasing the upper limit of braking torque as the oil temperature rises, eliminating sudden torque changes at the temperature critical point; simultaneously, a dynamic torque limiting strategy based on the oil temperature rise rate is introduced, linearly reducing the output torque according to the temperature rise gradient when the oil temperature rises too quickly at low temperatures, significantly reducing the internal shear heat of high-viscosity oil, effectively protecting core components such as the valve body and rotor, and solving the shortcomings of traditional solutions that lack targeted protection at low temperatures and are prone to component fatigue damage.

[0019] This invention uses a combination of multiple parameters, including oil temperature rise rate, downhill gradient, duration of continuous load, vehicle speed, and engine coolant temperature, to predict thermal load. It does not require waiting for the oil temperature to reach the protection threshold. Once signs of overheating, such as rapid temperature rise, long downhill slopes with steep gradients, or insufficient heat dissipation at low speeds, are identified, graded pre-reduction torque control can be initiated in advance to suppress the continuous accumulation of heat from the source. This significantly reduces the probability of retarder failure due to high temperature and brake capacity decay, and improves the reliability of auxiliary braking in long downhill heavy-load scenarios.

[0020] This invention employs a three-level basic torque reduction coefficient to match different overheating risk conditions in high-temperature scenarios, superimposed with dual compensation coefficients for low-speed windward heat dissipation correction and graded heat dissipation correction for engine coolant temperature, to adjust the output torque in a layered and progressive manner, avoiding a single threshold-based large torque reduction; at the same time, it limits linear torque in the low-temperature range and sets a 1.2s smooth torque recovery logic in the high and low temperature protection exit phase, so that torque and oil pressure are continuously and gradually output throughout the entire process without abrupt changes, completely solving the problem of vehicle body jerking and ride shock caused by sudden increases and decreases in braking force under extreme conditions, and improving the braking comfort and driving stability of the entire vehicle.

[0021] This invention differentiates control measures for various extreme scenarios, including low and high temperatures. In low-temperature environments, it retains the basic braking torque to meet basic deceleration requirements, while in high-temperature environments, it predicts torque reduction and only moderately weakens braking force rather than completely cutting off auxiliary braking. At the same time, it clarifies that this control strategy has a lower priority than hardware extreme fault protection. Under the premise of avoiding the risk of retarder damage, it maximizes the retention of the retarder's auxiliary braking capability, continuously shares the load of the service brakes, reduces brake pad wear, and significantly improves the downhill driving safety redundancy of long-distance transport vehicles in mountainous areas and extremely cold / hot regions. Attached Figure Description

[0022] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0023] Figure 1 This is a flowchart of a retarder braking torque control method under extreme operating conditions provided by one or more embodiments of the present invention.

[0024] Figure 2 This is a structural diagram of a retarder braking torque control system under extreme operating conditions provided by one or more embodiments of the present invention.

[0025] Figure 3 This is a block diagram of an electronic device for a retarder braking torque control method under extreme operating conditions, provided by one or more embodiments of the present invention. Detailed Implementation

[0026] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Figure 1 This is a flowchart of a retarder braking torque control method under extreme operating conditions provided by one or more embodiments of the present invention.

[0028] like Figure 1 As shown, it includes the following steps: Step S1: Collect multi-dimensional operating condition signals; The controller collects multi-dimensional operating parameters in real time through the vehicle-mounted sensor network. These multi-dimensional operating parameters include retarder oil temperature, oil temperature rise rate, vehicle speed, current road gradient, engine coolant temperature, and the target braking torque input by the driver through braking operations. The oil temperature rise rate is calculated in real time by the controller based on the oil temperature difference within a unit sampling period. The road gradient can be obtained through vehicle tilt sensors or by analyzing navigation terrain data.

[0029] Step S2, establish hierarchical torque constraint logic: When the real-time oil temperature of the retarder is lower than the preset low temperature threshold, the upper limit of the output torque is set according to the oil temperature gradient, and the torque limit amplitude is dynamically adjusted according to the oil temperature rise rate; when the oil temperature is lower than the preset extremely low temperature threshold, active preheating control is activated and the maximum output torque is constrained; a low temperature constraint target torque is generated. When the preset thermal overload risk condition is detected, the graded torque reduction control is activated, and the torque reduction magnitude is superimposed and corrected in combination with the vehicle driving status and the vehicle's heat dissipation capacity; a high-temperature correction target torque is generated. Specifically, for low-temperature operating conditions, a gradient temperature threshold layered control is adopted, combined with dynamic correction of the upper limit of braking torque based on the rate of oil temperature change. This is achieved through a three-level progressive control logic, including extreme cold preheating protection, wide-temperature-range linear torque release, and dynamic torque limiting based on the rate of temperature rise at low temperatures. Extreme cold preheating protection: A preset extreme cold temperature threshold is set. When the retarder oil temperature is detected to be lower than the extreme cold temperature threshold, the controller outputs a low duty cycle oil pressure signal to drive the proportional valve. The oil is circulated and preheated with low oil pressure. At the same time, the maximum braking torque is limited to the set ratio of the rated torque to avoid impact damage to the seals and transmission components caused by high viscosity oil at low temperature. When the oil temperature rises above the extreme cold temperature threshold, the extreme cold preheating protection is automatically deactivated.

[0030] Wide-temperature-range linear torque release: With a preset ambient temperature boundary temperature, within the range from the extreme cold temperature threshold to the ambient temperature boundary temperature, the upper limit of the allowable torque increases linearly with the rise of oil temperature, and the torque limit is gradually released as the oil temperature rises, so as to achieve a smooth release of braking capacity in the low-temperature range.

[0031] Dynamic torque limiting at low temperature rise rate: When the oil temperature is below the normal temperature boundary, a linear torque limiting coefficient is set in segments according to the oil temperature rise rate. The faster the temperature rise rate, the stronger the torque output limitation, thus suppressing the oil temperature from rising too quickly.

[0032] Under low-temperature conditions, the final output braking torque is calculated by coupling the upper limit of torque corresponding to the temperature range and the torque limiting coefficient corresponding to the temperature rise rate: first, the upper limit of torque constraint value of the corresponding temperature range is matched by the current oil temperature, then the dynamic torque limiting coefficient is obtained by combining the real-time oil temperature rise rate, and the upper limit of torque constraint value is multiplied by the dynamic torque limiting coefficient to obtain the final allowable braking torque under low-temperature conditions.

[0033] Among them, the dynamic torque limiting coefficient changes linearly with the temperature rise rate: when the temperature rise rate is lower than the low-speed temperature rise threshold, the dynamic torque limiting coefficient is 1, and no additional torque limiting is applied; when the temperature rise rate is in the range between the low-speed temperature rise threshold and the high-speed temperature rise threshold, the torque limiting coefficient decreases linearly with the increase of the temperature rise rate; when the temperature rise rate exceeds the high-speed temperature rise threshold, the torque limiting coefficient maintains a fixed minimum value, locking the maximum torque limiting amplitude.

[0034] For high-temperature operating conditions, based on the joint prediction of heat load using multiple parameters, a multi-level coefficient superposition correction method is adopted to pre-reduce the braking torque, as follows: First, three types of overheating risk judgment conditions are set: rapid oil temperature rise, long-term steep slope and heavy load downhill driving, and low-speed and low-heat driving. Pre-torque reduction control is activated when any one of the conditions is met. The corresponding basic torque reduction coefficient is configured according to the combination of risk types. The more risk types that are triggered at the same time, the greater the basic torque reduction.

[0035] Based on this, a two-stage torque correction mechanism is also set up for high-temperature operating conditions to perform secondary attenuation of the basic output torque: The first level is low-speed heat dissipation correction: a low-speed threshold is preset. When the vehicle speed is lower than the low-speed threshold, the retarder's air-cooling efficiency drops significantly. At this time, the basic output torque is further multiplied by the low-speed attenuation coefficient. The lower the vehicle speed, the smaller the attenuation coefficient.

[0036] The second level is the vehicle cooling system classification correction: based on the engine coolant temperature, multiple heat dissipation levels are divided. The worse the vehicle cooling conditions, the greater the torque reduction.

[0037] The final allowable output torque under high-temperature conditions is the constraint value obtained by multiplying the driver's target braking torque by the basic torque reduction coefficient, the low-speed heat dissipation correction coefficient, and the cooling system graded correction coefficient in sequence.

[0038] Step S3: Convert the low-temperature constraint target torque and the high-temperature correction target torque into oil pressure signals to control the proportional valve to output braking force. Specifically, the controller will match the target torque after final constraint to the corresponding target oil pressure through a preset torque-oil pressure mapping table, and output the control signal by continuously adjusting the duty cycle of the proportional valve to achieve smooth output of braking force, eliminate abrupt changes in braking force, and avoid jerking during the braking process.

[0039] Step S4: After the operating condition risk is eliminated, a gradual transition strategy is adopted to restore the original requested torque. The execution priority of the layered torque constraint logic is lower than that of the highest level of vehicle fault protection logic.

[0040] Specifically, once the controller detects that both high and low temperature risk conditions have been eliminated and all risk assessment conditions have been cleared, a fixed transition period is set. During this period, the output oil pressure is gradually increased to smoothly increase the braking force until it returns to the driver's original torque request. This avoids sudden torque surges that could cause vehicle impact and ensures ride comfort. Furthermore, the gradual transition recovery strategy is as follows: after exiting the high and low temperature risk conditions, a fixed transition period is set to gradually increase the oil pressure and smoothly restore the braking force to the driver's original torque request.

[0041] Furthermore, the final output braking torque under low-temperature conditions is calculated by coupling the upper limit of torque corresponding to the temperature range and the torque limiting coefficient corresponding to the temperature rise rate, including: First, obtain the torque upper limit constraint value corresponding to the temperature through the oil temperature range, then obtain the dynamic torque limiting coefficient by combining the real-time oil temperature rise rate, and multiply the torque upper limit constraint value with the dynamic torque limiting coefficient to obtain the final allowable output braking torque under low temperature conditions. The dynamic torque limiting coefficient changes linearly with the temperature rise rate in a piecewise manner: there is no torque limiting when the temperature rise rate is below the low-speed temperature rise threshold; when the temperature rise rate is in the temperature rise threshold range, the torque limiting coefficient decreases linearly with the increase of the temperature rise rate; after the temperature rise rate exceeds the high-speed temperature rise threshold, the torque limiting coefficient remains at a fixed minimum value.

[0042] Specifically, through a three-level progressive logic of extreme cold preheating protection, wide temperature range linear release, and dynamic torque limiting at the temperature rise rate, it not only solves the problem of component wear and seal failure caused by high torque output under extreme cold conditions, but also avoids abnormal oil temperature spikes by dynamically correcting the temperature rise rate. Under the premise of protecting the retarder hardware, it maximizes the preservation of braking capacity and improves braking response and availability under low temperature extreme conditions.

[0043] By jointly identifying overheating risks using multiple parameters such as oil temperature, gradient, and vehicle speed, pre-torque reduction control is implemented before the oil temperature reaches the limit, rather than passively limiting torque after exceeding the limit, which can effectively delay the accumulation of heat load. With the addition of a two-stage attenuation mechanism of low-speed heat dissipation correction and vehicle cooling state correction, the actual heat dissipation capacity under different driving scenarios is accurately matched, which greatly improves the thermal reliability and continuous braking capability of the retarder under extreme conditions such as long downhill slopes and low-speed congestion.

[0044] During the high and low temperature constraint intervention phase, the torque is linearly changed by continuously adjusting the pressure of the proportional valve. During the risk relief phase, the torque is gradually restored by changing the pressure over a fixed period of time. This process eliminates sudden torque jumps and avoids braking jerking and vehicle lurching, ensuring the smoothness of the braking process and driving stability.

[0045] By integrating multi-dimensional signals such as oil temperature, temperature rise rate, vehicle speed, road gradient, and engine coolant temperature, differentiated constraint logic is designed for different extreme working conditions such as low temperature and high temperature. The control logic is more in line with the actual thermal load and working state of the retarder, and can be adapted to various extreme working conditions such as extremely cold environment, long downhill distance, and low speed and low heat dissipation driving.

[0046] The execution priority of the layered torque constraint logic is set to be lower than that of the highest level of vehicle fault protection logic. When the vehicle experiences extreme faults, the execution of the safety strategy is prioritized. While optimizing braking performance under extreme conditions, the bottom line of vehicle braking safety is firmly maintained.

[0047] Figure 2 This is a structural diagram of a retarder braking torque control system under extreme operating conditions provided by one or more embodiments of the present invention.

[0048] like Figure 2 As shown, it includes: Signal acquisition module, torque constraint calculation module, and hydraulic output control module; The signal acquisition module is used to acquire multi-dimensional operating condition signals, including: retarder oil temperature, oil temperature rise rate, vehicle speed, and road gradient. The torque constraint calculation module is used to establish hierarchical torque constraint logic, which includes a low-temperature operating condition control branch and a high-temperature operating condition control branch. The low-temperature operating condition control branch is used to set the upper limit of output torque according to the oil temperature gradient when it is determined that the real-time oil temperature of the retarder is lower than the preset low-temperature threshold, and to dynamically adjust the torque limit amplitude according to the oil temperature rise rate; when it is determined that the oil temperature is lower than the preset extreme low temperature threshold, it generates an active preheating control command and constrains the maximum output torque, and outputs the low-temperature constraint target torque. The high-temperature operating condition control branch is used to generate graded torque reduction control commands when the preset thermal overload risk conditions are met, and to combine the vehicle driving status and the vehicle's heat dissipation capacity to superimpose and correct the torque reduction magnitude, and output the high-temperature correction target torque. The hydraulic output control module is used to receive the low-temperature constraint target torque and the high-temperature correction target torque, convert them into hydraulic signals and output them to the proportional valve to control the braking force output; It is also used to control the output torque to return to the original requested torque according to the gradual transition strategy after the working condition risk is eliminated.

[0049] It is worth noting that although only some basic functional modules are disclosed in this embodiment, it does not mean that the composition of this system is limited to the above-mentioned basic functional modules. On the contrary, what this embodiment intends to express is that, based on the above-mentioned basic functional modules, those skilled in the art can arbitrarily add one or more functional modules in combination with existing technology to form an infinite number of embodiments or technical solutions. That is to say, this system is open rather than closed. The fact that this embodiment only discloses a few basic functional modules does not mean that the scope of protection of the claims of this invention is limited to the disclosed basic functional modules. At the same time, for the convenience of description, the above device is described separately according to its functions as various units and modules. Of course, in implementing this invention, the functions of each unit and module can be implemented in one or more software and / or hardware.

[0050] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0051] In one embodiment, a method for controlling the braking torque of a retarder under extreme low-temperature and high-temperature conditions is provided. The method is characterized by disclosing a preheating and graded torque reduction protection control method for the retarder under extreme high and low temperature conditions. The control unit collects oil temperature, oil temperature rise rate, vehicle speed, road gradient, coolant temperature, and requested braking torque to achieve full-condition protection. For low-temperature conditions, a multi-level control mechanism is set up. In extremely cold conditions, preheating is initiated and high torque output is limited. In the low-temperature range, the torque limit is gradually released according to the temperature gradient, while the output torque is dynamically adjusted based on the oil temperature rise rate to avoid equipment damage caused by high viscosity of the low-temperature oil. For high-temperature conditions, heat load prediction is performed based on multiple parameters, and graded torque reduction is initiated in advance. The torque reduction magnitude is corrected and optimized according to the vehicle's driving status and overall vehicle cooling capacity. The system converts the calculated torque value into a corresponding oil pressure and adjusts the proportional valve to achieve stable torque output. When the abnormal condition disappears, the control torque is smoothly restored to the original requested value. This invention changes the traditional method of passive protection based solely on oil temperature, and can avoid the risk of thermal overload in advance, effectively improving problems such as sudden changes in braking torque and vehicle impact under extreme working conditions, thereby enhancing the working stability of the retarder and the driving safety of the vehicle.

[0052] S1. The retarder control unit acquires the following signals: real-time retarder oil temperature T, oil temperature rise rate dT / dt, vehicle speed v, road gradient s, engine coolant temperature, and the driver's requested retarder target torque. S2, Low Temperature Operating Condition Control Method S2.1, Extremely low temperature preheating mode (starting temperature T < -30℃) If the retarder oil temperature is below -30℃ after vehicle startup, the retarder preheating function will be forcibly activated. During vehicle start-up, the retarder control unit controls the proportional valve opening to bring the retarder oil pressure to the set oil pressure Ps1 (Ps1 is generally 2 bar). When the oil temperature reaches -30℃, the above control will immediately cease. Furthermore, high braking torque output is prohibited. The high braking torque threshold is 50% of the rated braking torque; that is, when the retarder control unit receives a request for more than 50% of the rated braking torque, its actual output braking torque will be limited to 50%.

[0053] S2.2 Low Temperature Limiting Mode (Activation Temperature: -30℃ to 0℃) This stage of torque control uses a linear torque upper limit (MAP). When the oil temperature is -30℃, the retarder's maximum responsive braking torque is 50% of the current rated braking torque. When the oil temperature is 0℃, the low-temperature limitation mode is removed, and the responsive braking torque is 100%. The torque limit is linearly interpolated from -30℃ to 0℃. (The lower the temperature, the greater the torque limit.) S2.3 Low Temperature Rise Rate Protection The retarder oil temperature is collected, and the oil temperature rise rate dT / dt is obtained. When the oil temperature is below 0℃ and dT / dt is greater than the set temperature rise rate ks1, in order to protect the oil under low temperature and high viscosity conditions, the retarder needs to reduce torque. The retarder control unit controls the output braking torque to be ks2 times the rated output torque (ks2 is generally taken as 60%-100%). The specific value corresponds to the actual temperature rise rate. The correspondence is that when the temperature rise rate is greater than 10℃ / s, the torque is limited to 60%; when the temperature rise rate is less than 3℃ / s, no torque limiting operation is performed; when the temperature rise rate is between 3℃ / s and 10℃ / s, the corresponding torque limiting ks2 is a linear interpolation of 100%-60%.

[0054] S3, High-Temperature Condition Multi-Parameter Heat Load Prediction Torque Reduction The retarder control unit acquires parameters such as temperature rise rate, gradient, vehicle speed, and coolant temperature, and predicts the retarder's thermal load based on these parameters. When the oil temperature rise rate dT / dt is detected to be greater than or equal to the set value ks3 (generally preferred to be 4℃ / s), it is determined that the retarder has a rapid overheating trend, and pre-torque reduction control is initiated in advance regardless of whether the current oil temperature has reached the protection threshold. When the road gradient is greater than the set value ks4 (generally preferred to be greater than 6%) and the duration exceeds Ts1 (generally preferred to be 5s), it is determined to be a continuous high-load downhill condition, and torque reduction control is activated to suppress the continuous accumulation of heat. When the vehicle speed is lower than the set value vs1 (generally preferred to be 30km / h), it is determined to be a condition where the vehicle speed is too low and the fan's cooling is insufficient, and the current torque reduction magnitude is corrected and superimposed to enhance the heat dissipation protection effect. S3.1 Setting the basic coefficient for graded torque reduction control The three-level base torque reduction coefficient is preset. Based on the driver's requested target torque, the initial output torque is calculated as follows: when only rapid temperature rise is triggered, the base torque reduction coefficient k1 = 0.85, and the output torque = requested torque. k1. Only when triggering a continuous downhill slope with a large gradient, the foundation torque reduction coefficient k2 = 0.90, and the output torque = requested torque. k2. When both rapid temperature rise and steep slope conditions are triggered simultaneously, the foundation torque reduction coefficient k3 = 0.75, and the output torque = the requested torque. k3.

[0055] S3.2, Low-speed weak heat dissipation control method When the vehicle is determined to be operating at low speed (v < vs1) and its wind cooling capacity is insufficient, all the aforementioned basic torque reduction coefficients are adjusted and superimposed. The correction coefficient k4 = 0.90, and the corrected output torque equals the basic calculated torque. k4.

[0056] S3.3, Correction of overall vehicle heat dissipation capacity The engine coolant temperature is used to classify the cooling level, and the torque reduction is further fine-tuned. The levels are as follows: Excellent cooling (coolant temperature < 95℃) – no additional correction is made, and the currently calculated torque is used. Average cooling (coolant temperature 95℃~103℃) – the output torque is multiplied by 0.95. Poor cooling (coolant temperature > 103℃) – the output torque is multiplied by 0.90.

[0057] S4, Other Control Execution The retarder braking torque output converts the final calculated output torque into the retarder target oil pressure by looking up a table. The working chamber oil pressure is adjusted by controlling the duty cycle of the proportional valve to achieve continuous and gradual torque change without step shock.

[0058] The braking torque control exit method under extreme low and high temperature conditions is as follows: when the temperature rise rate, slope, and vehicle speed are no longer triggered, the oil pressure is gradually restored to normal according to the set Ts2 time (Ts2 is generally preferred to be 1.2s), and the output torque is gradually restored to the torque originally requested by the driver.

[0059] The braking torque control method for the extreme operating conditions of low temperature and high temperature has a priority that is lower than the priority of the pre-torque reduction control logic, which is lower than the limit fault protection.

[0060] The above description is a preferred embodiment of the present invention. Any changes and modifications made within the scope claimed by the present invention are within the protection scope of the present invention.

[0061] Figure 3 This is a block diagram of an electronic device for a retarder braking torque control method under extreme operating conditions, provided by one or more embodiments of the present invention.

[0062] like Figure 3 As shown, the present invention provides an electronic device, including: a processor, a communication interface, a memory, and a communication bus, wherein the processor, the communication interface, and the memory communicate with each other through the communication bus; The memory stores a computer program, which, when executed by the processor, causes the processor to perform the steps of a retarder limit condition braking torque control method.

[0063] The present invention also provides a computer-readable storage medium storing a computer program executable by an electronic device, which, when run on the electronic device, causes the electronic device to perform the steps of a retarder limit condition braking torque control method.

[0064] For the sake of simplicity, the method embodiments are described as a series of actions. However, those skilled in the art should understand that the embodiments of the present invention are not limited to the described order of actions, because according to the embodiments of the present invention, some steps can be performed in other orders or simultaneously. Furthermore, those skilled in the art should also understand that the embodiments described in the specification are preferred embodiments, and the actions involved are not necessarily essential to the embodiments of the present invention.

[0065] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of this application.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling the braking torque of a retarder under extreme operating conditions, characterized in that, Includes the following steps: Collect multi-dimensional operating condition signals; The multi-dimensional operating condition signal includes at least: oil temperature rise rate; Based on the collected multi-dimensional operating condition signals, a hierarchical torque constraint logic is established: When the real-time oil temperature of the retarder is lower than the preset low temperature threshold, the upper limit of the output torque is set according to the oil temperature gradient, and the torque limit amplitude is dynamically adjusted according to the oil temperature rise rate; when the oil temperature is lower than the preset extremely low temperature threshold, active preheating control is activated and the maximum output torque is constrained; a low temperature constraint target torque is generated. When the preset thermal overload risk condition is detected, the graded torque reduction control is activated, and the torque reduction magnitude is superimposed and corrected in combination with the vehicle driving status and the vehicle's heat dissipation capacity; a high-temperature correction target torque is generated. The low-temperature constraint target torque and the high-temperature correction target torque are converted into oil pressure signals to control the proportional valve to output braking force. Once the operating condition risk is eliminated, a gradual transition strategy is adopted to restore the original requested torque. The execution priority of the layered torque constraint logic is lower than that of the highest level of vehicle fault protection logic.

2. The method for controlling the braking torque of a retarder under extreme operating conditions according to claim 1, characterized in that, The oil temperature gradient setting includes the following: Three-level progressive control logic: extreme cold preheating protection, wide temperature range linear torque release, and low temperature temperature rise rate dynamic torque limiting; The extreme cold preheating protection outputs low oil pressure for preheating and limits the maximum braking torque when the oil temperature is below the extreme cold threshold. The protection is deactivated when the oil temperature rises to the extreme cold threshold. The wide-temperature-range linear torque release means that within the temperature range from the extreme cold threshold to the normal temperature boundary, the upper limit of the allowable torque increases linearly with the increase of oil temperature. The low-temperature temperature rise rate dynamic torque limiting: when the oil temperature is lower than the normal temperature boundary temperature, the linear torque limiting coefficient is set in segments according to the oil temperature rise rate. The faster the temperature rise, the stronger the torque output limitation. The final output braking torque under low-temperature conditions is calculated by coupling the upper limit of torque corresponding to the temperature range and the torque limiting coefficient corresponding to the temperature rise rate.

3. The method for controlling the braking torque of a retarder under extreme operating conditions according to claim 1, characterized in that, The preset thermal overload risk conditions include: When the oil temperature rise rate exceeds a preset threshold, when the road gradient is greater than a preset threshold and exceeds a preset time, and when the current vehicle speed is lower than a preset threshold; Pre-dip torque is initiated when any condition is met; Configure the corresponding basic moment reduction coefficient based on the combination type that triggers the risk; the more risks are combined, the greater the basic moment reduction will be.

4. The method for controlling the braking torque of a retarder under extreme operating conditions according to claim 1, characterized in that, The method of combining vehicle driving conditions and overall vehicle heat dissipation capacity to superimpose and correct the torque reduction magnitude also includes: The first level is low-speed heat dissipation correction, which further reduces the basic output torque when the vehicle is traveling below the low-speed threshold. The second level is the vehicle cooling system classification correction, which classifies the heat dissipation level according to the engine coolant temperature. The worse the cooling conditions, the greater the torque reduction.

5. The method for controlling the braking torque of a retarder under extreme operating conditions according to claim 1, characterized in that, The braking force output of the control proportional valve is achieved by matching the target oil pressure according to the final constraint torque by looking up a table, and continuously adjusting the duty cycle of the proportional valve.

6. The method for controlling the braking torque of a retarder under extreme operating conditions according to claim 1, characterized in that, The gradual transition strategy is as follows: after leaving the high and low temperature risk conditions, the oil pressure is gradually increased after a fixed transition time is set, and the braking force is smoothly restored to the original torque requested by the driver.

7. The method for controlling the braking torque of a retarder under extreme operating conditions according to claim 1, characterized in that, The generated cryogenic constraint target torque includes: First, obtain the torque upper limit constraint value corresponding to the temperature through the oil temperature range, then obtain the dynamic torque limiting coefficient by combining the real-time oil temperature rise rate, and multiply the torque upper limit constraint value with the dynamic torque limiting coefficient to obtain the final allowable output braking torque under low temperature conditions. The dynamic torque limiting coefficient changes linearly with the temperature rise rate in a piecewise manner: there is no torque limiting when the temperature rise rate is below the low-speed temperature rise threshold; when the temperature rise rate is in the temperature rise threshold range, the torque limiting coefficient decreases linearly with the increase of the temperature rise rate; after the temperature rise rate exceeds the high-speed temperature rise threshold, the torque limiting coefficient maintains a fixed minimum value.

8. A retarder braking torque control system under extreme operating conditions, characterized in that, The control system is used to execute the control method according to any one of claims 1-7, including: Signal acquisition module, torque constraint calculation module, and hydraulic output control module; The signal acquisition module is used to acquire multi-dimensional operating condition signals, including: retarder oil temperature, oil temperature rise rate, vehicle speed, and road gradient. The torque constraint calculation module is used to establish hierarchical torque constraint logic, which includes a low-temperature operating condition control branch and a high-temperature operating condition control branch. The low-temperature operating condition control branch is used to set the upper limit of output torque according to the oil temperature gradient when it is determined that the real-time oil temperature of the retarder is lower than the preset low-temperature threshold, and to dynamically adjust the torque limit amplitude according to the oil temperature rise rate; when it is determined that the oil temperature is lower than the preset extreme low temperature threshold, it generates an active preheating control command and constrains the maximum output torque, and outputs the low-temperature constraint target torque. The high-temperature operating condition control branch is used to generate graded torque reduction control commands when the preset thermal overload risk conditions are met, and to combine the vehicle driving status and the vehicle's heat dissipation capacity to superimpose and correct the torque reduction magnitude, and output the high-temperature correction target torque. The hydraulic output control module is used to receive the low-temperature constraint target torque and the high-temperature correction target torque, convert them into hydraulic signals and output them to the proportional valve to control the braking force output; It is also used to control the output torque to return to the original requested torque according to the gradual transition strategy after the working condition risk is eliminated.

9. An electronic device, characterized in that, include: The processor, communication interface, memory, and communication bus are connected, with the processor, communication interface, and memory communicating with each other via the communication bus. The memory stores a computer program, which, when executed by the processor, causes the processor to perform the steps of the retarder limit condition braking torque control method according to any one of claims 1-7.

10. A computer-readable storage medium, characterized in that, It stores a computer program executable by an electronic device, which, when run on the electronic device, causes the electronic device to perform the steps of the retarder limit condition braking torque control method as described in any one of claims 1-7.

Images