Hybrid heavy vehicle auxiliary brake torque distribution method and apparatus

Abstract

The application discloses a kind of hybrid heavy vehicle auxiliary brake torque distribution method and device. The current auxiliary brake gear of vehicle, current vehicle speed, motor maximum available brake torque, retarder maximum available brake torque and engine maximum available brake torque are obtained;According to the current auxiliary brake gear and current vehicle speed, the driver demand brake total torque is calculated;According to motor maximum available brake torque, retarder maximum available brake torque, engine maximum available brake torque and driver demand brake total torque, according to preset priority brake torque distribution principle, driving motor, retarder and engine output brake torque are controlled.The application converts the current auxiliary brake gear into the explicit driver demand brake total torque, and is distributed according to the priority of motor first, hydraulic retarder second and engine last.Under the premise of meeting brake demand, maximum utilization of motor is carried out regenerative braking, and the economy of the whole vehicle is improved.

Description

Technical Field

[0001] This invention relates to the field of braking control technology for medium and heavy-duty hybrid vehicles, and in particular to a method and device for auxiliary braking torque distribution of hybrid heavy-duty vehicles. Background Technology

[0002] Medium and heavy-duty hybrid vehicles are generally equipped with a variety of auxiliary braking devices, such as regenerative braking of the drive motor, hydraulic retarder braking, and engine braking. These vehicles often have multiple auxiliary braking levels for the driver to use in conditions such as long downhill slopes.

[0003] In existing technologies, multi-power-source auxiliary braking typically employs a fixed distribution ratio. This method fails to adequately integrate gear selection with the vehicle's real-time status, making it impossible to maximize brake energy recovery while ensuring braking demand. Furthermore, when the capacity of a particular braking source is limited by temperature, engine speed, or state of charge, a fixed distribution strategy can easily lead to insufficient utilization of braking capacity or braking shocks.

[0004] Therefore, a method is needed that can dynamically and prioritize the allocation of braking torque according to the driver's auxiliary braking gear requirements, so as to ensure full utilization of braking capacity and driving safety while prioritizing energy recovery. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method and apparatus for auxiliary braking torque distribution in hybrid heavy-duty vehicles.

[0006] According to one aspect of the present invention, a method for auxiliary braking torque distribution in a hybrid heavy-duty vehicle is provided, comprising:

[0007] Obtain the vehicle's current auxiliary braking gear, current vehicle speed, maximum available braking torque of the electric motor, maximum available braking torque of the retarder, and maximum available braking torque of the engine;

[0008] Calculate the total braking torque required by the driver based on the current auxiliary braking gear and the current vehicle speed;

[0009] Based on the maximum available braking torque of the motor, the maximum available braking torque of the retarder, the maximum available braking torque of the engine, and the total braking torque required by the driver, the output braking torque of the drive motor, retarder, and engine is controlled according to a preset priority braking torque allocation principle.

[0010] Optionally, the preset priority braking torque distribution principle is as follows:

[0011] The total braking torque required by the driver is preferentially allocated to the drive motor to perform regenerative braking; if the maximum available braking torque of the motor is less than the total braking torque required by the driver, the drive motor is controlled to output the maximum available braking torque of the motor, and the first remaining required torque is calculated.

[0012] The first remaining required torque is allocated to the retarder; if the maximum available braking torque of the retarder is less than the first remaining required torque, the hydraulic retarder is controlled to output the maximum available braking torque of the retarder, and the second remaining required torque is calculated.

[0013] The second remaining required torque is distributed to the engine to perform auxiliary braking.

[0014] Optionally, after allocating the second remaining required torque to the engine to perform auxiliary braking, the method further includes:

[0015] If the second remaining required torque is greater than the engine's maximum available braking torque, the engine is controlled to output its maximum available braking torque, while an alarm signal indicating insufficient auxiliary braking capacity is generated and issued, and the total braking torque required by the driver is limited to the currently allocated total braking torque.

[0016] Optionally, the distribution of the second remaining demand torque to the engine includes:

[0017] The second remaining required torque is compared with the preset engine braking torque;

[0018] If the preset engine braking torque is greater than or equal to the second remaining required torque, then control the engine to output the preset engine braking torque;

[0019] If the preset engine braking torque is less than the second remaining required torque, then control the engine to output 100% braking torque.

[0020] Optionally, calculating the driver's required total braking torque based on the current auxiliary braking gear and the current vehicle speed includes:

[0021] Based on the preset calibrated gear-vehicle speed-basic required torque mapping table, the basic required braking torque under the corresponding working condition is obtained by looking up the table;

[0022] Based on the vehicle's current total mass and the road gradient, a correction coefficient is determined, and the basic required braking torque is corrected to obtain the total braking torque required by the driver.

[0023] Optionally, the correction coefficient is composed of the ratio of the vehicle's current total mass to its unloaded reference mass and the slope correction factor, and the total braking torque required by the driver satisfies the following formula:

[0024] In the formula, To meet the driver's braking torque requirements, Based on the required braking torque, The current gross vehicle weight. For the vehicle's unloaded reference mass, This is the slope correction factor.

[0025] Optionally, the maximum available braking torque of the motor is calculated and determined in real time based on the current speed of the drive motor, the motor temperature, and the state of charge of the power battery; when the state of charge of the power battery is higher than a preset safety threshold, the maximum available braking torque of the motor is limited to be reduced or set to zero to avoid overcharging of the power battery;

[0026] The maximum available braking torque of the retarder is determined based on the input shaft speed and oil temperature of the retarder.

[0027] The maximum available braking torque of the engine is determined based on the current engine speed and the operating state of the exhaust brake valve or compression release brake.

[0028] Optionally, after controlling the output braking torque of the drive motor, retarder, and engine according to a preset priority braking torque allocation principle based on the maximum available braking torque of the motor, the maximum available braking torque of the retarder, the maximum available braking torque of the engine, and the total braking torque required by the driver, the method further includes:

[0029] If the total braking torque of all braking sources after allocation is greater than the total braking torque required by the driver, the total braking torque will be gradually reduced in the order of first reducing the braking torque of the retarder and then reducing the braking torque of the drive motor, until the total braking torque matches the total braking torque required by the driver.

[0030] Optionally, the braking torque variation rates of the drive motor, retarder, and engine are uniformly controlled based on the maximum value of the braking torque variation within a single cycle of the three components.

[0031] According to another aspect of the present invention, a hybrid heavy-duty vehicle auxiliary braking torque distribution device is provided, comprising:

[0032] The acquisition module is used to acquire the vehicle's current auxiliary braking gear, current vehicle speed, maximum available braking torque of the motor, maximum available braking torque of the retarder, and maximum available braking torque of the engine.

[0033] The calculation module is used to calculate the total braking torque required by the driver based on the current auxiliary braking gear and the current vehicle speed;

[0034] The control allocation module is used to control the output braking torque of the drive motor, the retarder, and the engine according to a preset priority braking torque allocation principle based on the maximum available braking torque of the motor, the maximum available braking torque of the retarder, the maximum available braking torque of the engine, and the total braking torque required by the driver.

[0035] This invention provides a method and apparatus for distributing auxiliary braking torque in hybrid heavy-duty vehicles. The method includes: acquiring the vehicle's current auxiliary braking gear, current vehicle speed, maximum available braking torque of the electric motor, maximum available braking torque of the retarder, and maximum available braking torque of the engine; calculating the total braking torque required by the driver based on the current auxiliary braking gear and current vehicle speed; and controlling the output braking torque of the drive motor, retarder, and engine according to a preset priority braking torque distribution principle based on the maximum available braking torque of the electric motor, retarder, engine, and total braking torque required by the driver. The technical solution provided by this invention calculates the total braking torque required by the driver based on the current auxiliary braking gear and current vehicle speed, and distributes it according to a priority order: electric motor first, hydraulic retarder second, and engine last. Under the premise of meeting braking requirements, the electric motor is used to the maximum extent for regenerative braking to recover braking energy and improve vehicle economy; the hydraulic retarder undertakes the remaining braking demand, leveraging its advantages of fast response and strong continuous braking capability, and avoiding overheating or overcharging of the motor and battery; engine braking serves as a last resort to ensure braking safety under extreme conditions. The entire allocation process is based on the vehicle's real-time capabilities and gear requirements, resulting in smooth control and strong adaptability.

[0036] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 A flowchart of an auxiliary braking torque distribution method for a hybrid heavy-duty vehicle provided in an embodiment of the present invention;

[0039] Figure 2 This is a schematic diagram of the structure of an auxiliary braking torque distribution device for a hybrid heavy-duty vehicle provided in an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of the electronic device for an auxiliary braking torque distribution method for a hybrid heavy-duty vehicle provided in an embodiment of the present invention. Detailed Implementation

[0041] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0042] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0043] Figure 1 The flowchart illustrates a method for auxiliary braking torque distribution in a hybrid heavy-duty vehicle, as provided in an embodiment of the present invention. This method can be executed by a hybrid heavy-duty vehicle auxiliary braking torque distribution device, which can be implemented in hardware and / or software and can be configured in any electronic device with communication capabilities. See also... Figure 1 The method includes:

[0044] S110: Obtain the vehicle's current auxiliary braking gear, current vehicle speed, maximum available braking torque of the electric motor, maximum available braking torque of the retarder, and maximum available braking torque of the engine.

[0045] The current auxiliary braking level is the driver's input command for the intensity of auxiliary braking, selected by the driver via the auxiliary braking lever or switch. This level signal is collected by the corresponding level detection unit and transmitted to the vehicle controller via hardwired connection or vehicle communication network. The auxiliary braking level has multiple different settings; the higher the level, the greater the target braking intensity. When the level is zero, it indicates no auxiliary braking request, and the vehicle controller terminates the distribution and output of auxiliary braking torque.

[0046] The current vehicle speed is a key input parameter for calculating the total braking torque required by the driver. The vehicle speed signal can be obtained from wheel speed sensors, transmission output shaft speed sensors, or directly from the verified vehicle speed signal obtained from the vehicle's CAN network. Since vehicle braking performance is directly related to driving speed, the same auxiliary braking gear corresponds to different basic braking torque requirements at different vehicle speeds. Therefore, accurate calculation of braking requirements must be performed in conjunction with vehicle speed.

[0047] The maximum available braking torque of the motor is the maximum regenerative braking torque that the drive motor can safely output under current operating conditions, representing the upper limit of the drive motor's current actual braking capacity. This parameter is calculated in real time by the motor controller and fed back to the vehicle controller. Its value is determined by the current speed of the drive motor, the motor operating temperature, the state of charge of the power battery, and the maximum allowable charging power of the battery. When the state of charge of the power battery is higher than a preset safety threshold, in order to prevent the power battery from overcharging, the motor controller will actively reduce the maximum available braking torque of the motor, or even limit it to zero, to protect the battery system.

[0048] The maximum usable braking torque of the retarder is the maximum braking torque that the hydraulic retarder can stably output under current operating conditions, representing the upper limit of the hydraulic retarder's current actual braking capacity. This parameter is calculated in real time by the retarder controller and sent to the vehicle controller. Its value is constrained by the input shaft speed and operating oil temperature of the hydraulic retarder. When the retarder oil temperature exceeds the safe operating range or the input shaft speed is too low, the retarder's braking capacity will decrease accordingly. The retarder controller will then update this maximum usable braking torque value synchronously to prevent the retarder from overheating and failing.

[0049] The maximum available braking torque of the engine is the maximum auxiliary braking torque that the engine can provide under current operating conditions, representing the upper limit of the engine's actual braking capability. This parameter is calculated in real time by the engine controller based on the current engine speed and the operating status of the exhaust brake valve or compression release brake mechanism, and is transmitted to the vehicle controller via the vehicle communication network as a supplement to the final braking capability of the auxiliary braking system.

[0050] By acquiring all the above parameters in real time, the subsequent braking torque distribution can always match the vehicle's current operating state and the capability boundaries of each braking source, avoiding the waste of capacity or braking shock caused by a fixed distribution strategy, and ensuring the safety and energy recovery efficiency of the braking process.

[0051] S120. Calculate the total braking torque required by the driver based on the current auxiliary braking gear and the current vehicle speed.

[0052] Specifically, the auxiliary braking gear corresponds to the driver's desired braking intensity level. The number of gears can be set according to the vehicle configuration; the higher the gear number, the greater the driver's desired auxiliary braking intensity. Vehicle speed is a key parameter affecting braking performance. At the same gear, the required braking torque varies at different speeds, therefore, braking demand needs to be precisely quantified based on vehicle speed. The vehicle controller pre-stores the gear-vehicle speed-basic required torque correspondence obtained through bench testing and real-vehicle calibration. During vehicle operation, the vehicle controller matches the currently collected auxiliary braking gear and current vehicle speed from the pre-stored correspondence to obtain the basic required braking torque for the current operating condition. This correspondence follows the physical characteristics of vehicle braking, typically exhibiting the following: at the same auxiliary braking gear, the basic required braking torque initially increases gradually with increasing vehicle speed, and then stabilizes after reaching a certain threshold, balancing braking smoothness at low speeds and braking efficiency at high speeds.

[0053] To further adapt to actual vehicle load and road conditions, and ensure that braking intensity matches the driving scenario, after obtaining the basic required braking torque, it is necessary to correct it based on the vehicle's current total mass and road gradient to ultimately obtain the driver's required total braking torque. Specifically, the larger the vehicle's total mass, the higher the braking torque required to maintain the same braking deceleration; the steeper the downhill slope, the stronger the acceleration tendency caused by the vehicle's gravity, and the higher the required braking torque. During the correction process, a mass correction coefficient corresponding to the current total mass is calculated based on the vehicle's unloaded reference mass; simultaneously, a gradient correction factor is calculated based on the current road gradient, with a larger gradient correction factor for steeper downhill slopes. The final driver's required total braking torque is the product of the basic required braking torque, the mass correction coefficient, and the gradient correction factor.

[0054] Through the above calculations, the driver's gear shifting can be transformed into a precise torque demand that matches the vehicle's real-time operating conditions. This ensures that the braking intensity meets the driver's expectations while avoiding insufficient braking capacity or excessive braking intensity due to changes in load and gradient, thus providing an accurate target benchmark for subsequent priority-based dynamic torque distribution.

[0055] S130: Based on the maximum available braking torque of the motor, the maximum available braking torque of the retarder, the maximum available braking torque of the engine, and the total braking torque required by the driver, control the output braking torque of the drive motor, the retarder, and the engine according to the preset priority braking torque distribution principle.

[0056] The specific principles for pre-priority braking torque distribution are as follows:

[0057] The system prioritizes allocating the total braking torque required by the driver to the drive motor for regenerative braking. If the maximum available braking torque of the motor is less than the total braking torque required by the driver, the drive motor is controlled to output its maximum available braking torque, and a first remaining required torque is calculated. This first remaining required torque is then allocated to the retarder. If the maximum available braking torque of the retarder is less than the first remaining required torque, the hydraulic retarder is controlled to output its maximum available braking torque, and a second remaining required torque is calculated. This second remaining required torque is then allocated to the engine for auxiliary braking.

[0058] Specifically, the preset priorities are set according to energy recovery benefits and braking response characteristics, with the first priority being regenerative braking of the drive motor. The vehicle controller first compares the total braking torque required by the driver with the maximum available braking torque of the motor: when the maximum available braking torque of the motor is greater than or equal to the total braking torque required by the driver, all braking demand is borne by the drive motor, and the hydraulic retarder and engine do not output braking torque, thereby maximizing the use of regenerative braking to recover energy; when the maximum available braking torque of the motor is less than the total braking torque required by the driver, the drive motor is controlled to output its maximum available braking torque under the current operating conditions, making full use of the motor's braking capacity. At the same time, the difference between the total braking torque required by the driver and the maximum available braking torque of the motor is calculated to obtain the first remaining demand torque, which is then assigned to the next priority braking source.

[0059] The second priority is hydraulic retarder braking, which relies on the hydraulic retarder's fast response and stable continuous braking capability to handle supplementary braking needs. The vehicle controller compares the previously obtained first remaining demand torque with the retarder's maximum available braking torque: when the retarder's maximum available braking torque is greater than or equal to the first remaining demand torque, the hydraulic retarder outputs a braking torque equal to the first remaining demand torque, thus covering all remaining braking needs, and the engine does not output braking torque; when the retarder's maximum available braking torque is still less than the first remaining demand torque, the controller controls the hydraulic retarder to output its maximum available braking torque under the current operating conditions, and simultaneously calculates the difference between the first remaining demand torque and the retarder's maximum available braking torque to obtain the second remaining demand torque, which is then handled by the last level, the third priority braking source.

[0060] The third priority is engine braking, which serves as the final safety supplement to the vehicle's auxiliary braking system, used to cover the remaining braking demand under extreme conditions. Based on the obtained second remaining torque demand, the vehicle controller performs matched control in conjunction with the engine's braking capacity classification.

[0061] During the torque distribution process, if the total output braking torque of the three types of braking sources is greater than the total braking torque required by the driver after the three-level priority distribution, the output values ​​of each braking source will be gradually adjusted back in the order of first reducing the braking torque of the hydraulic retarder and then reducing the braking torque of the drive motor, until the total output braking torque matches the total braking torque required by the driver. This ensures that the braking intensity accurately matches the driver's operating intention and avoids the braking intensity from exceeding expectations.

[0062] To further improve the smoothness of the braking process and avoid braking shock caused by sudden changes in braking torque, the vehicle controller uniformly constrains the braking torque change rate of the drive motor, hydraulic retarder and engine. The maximum value of the braking torque change of the three in a single control cycle is used as the benchmark to control the torque change rate of each braking source, ensuring that the torque output of each braking source changes synchronously and smoothly, thereby improving driving comfort and system reliability.

[0063] By using the above-mentioned priority-based, dynamic-adaptive control method, the ability fluctuations of each braking source caused by factors such as temperature, speed, and battery state of charge can be adapted to the situation. This ensures the priority recovery of braking energy and fully leverages the performance advantages of different braking sources, achieving a balance between braking safety, smoothness, and economy.

[0064] It should be noted that after the second remaining demand torque is allocated to the engine to perform auxiliary braking, if the second remaining demand torque is greater than the engine's maximum available braking torque, the engine is controlled to output its maximum available braking torque, and an alarm signal indicating insufficient auxiliary braking capacity is generated and issued, while the total braking torque required by the driver is limited to the currently allocated total braking torque.

[0065] The technical solution provided by this invention calculates the total braking torque required by the driver based on the current auxiliary braking gear and current vehicle speed, and allocates it according to a priority order: electric motor first, hydraulic retarder second, and engine last. While meeting braking requirements, it maximizes the use of the electric motor for regenerative braking, recovering braking energy and improving overall vehicle economy; the hydraulic retarder handles the remaining braking demand, leveraging its advantages of fast response and strong continuous braking capability, while preventing overheating or overcharging of the motor and battery; engine braking serves as a final supplement, ensuring braking safety under extreme conditions. The entire allocation process is based on the vehicle's real-time capabilities and gear requirements, resulting in smooth control and strong adaptability.

[0066] In some other embodiments, optionally, distributing the second remaining demand torque to the engine includes:

[0067] The second remaining required torque is compared with the preset engine braking torque; if the preset engine braking torque is greater than or equal to the second remaining required torque, the engine is controlled to output the preset engine braking torque; if the preset engine braking torque is less than the second remaining required torque, the engine is controlled to output 100% braking torque.

[0068] The preset engine braking torque is a pre-calibrated braking torque threshold corresponding to the engine's partial braking gear. This torque value is set based on the hardware characteristics of the engine braking mechanism and the vehicle's braking smoothness requirements, and usually corresponds to the engine's output capacity under half-gear braking conditions. During vehicle operation, this preset value can be corrected in real time according to the engine's current speed to match the actual braking characteristics of the engine at different speeds.

[0069] Specifically, when the preset engine braking torque is greater than or equal to the second remaining braking demand torque, it indicates that the current remaining braking demand is within the coverage range of the engine's partial braking capacity. Therefore, full engine braking is not required. The vehicle controller sends a control command to the engine controller corresponding to the preset engine braking torque, controlling the engine to output the preset braking torque value, which fully covers the second remaining braking demand torque. This partial braking engagement control method effectively reduces the torque jump at the moment of engine braking engagement, weakens the braking impact, improves vehicle ride smoothness, and simultaneously reduces the workload and wear rate of the engine braking mechanism.

[0070] When the preset engine braking torque is less than the second remaining required torque, it means that the current remaining braking demand has exceeded the bearing capacity of some engine braking gears. The vehicle controller sends a full-load braking control command to the engine controller, controlling the engine to output 100% braking torque, that is, outputting the maximum available braking torque that the engine can provide under the current working conditions, to supplement the remaining braking demand with the maximum braking capacity, and to match the driver's expected braking intensity as much as possible, so as to ensure the driving braking performance under conditions such as long downhill.

[0071] Through the above-mentioned hierarchical comparison and step-by-step output control logic, the smooth intervention of engine braking can be achieved, avoiding the impact of sudden braking torque on the transmission system. While ensuring sufficient braking capacity, it also takes into account driving comfort and the service life of system components.

[0072] In some other embodiments, optionally, S120 includes:

[0073] S1201. Based on the preset calibrated gear-vehicle speed-basic required torque mapping table, look up the table to obtain the basic required braking torque under the corresponding working condition; determine the correction coefficient based on the current total mass of the vehicle and the road slope, correct the basic required braking torque, and obtain the total required braking torque for the driver.

[0074] The unloaded reference mass is a pre-calibrated baseline parameter for the vehicle, corresponding to the total mass of the vehicle in its unloaded, prepared state. This parameter is determined through actual vehicle weighing tests during the vehicle development phase and is pre-stored in the non-volatile storage unit of the vehicle controller. It is a fixed baseline value and does not require real-time data collection and updates during vehicle operation; it serves as the calculation benchmark for load correction. The current total mass of the vehicle is the actual total mass of the vehicle after loading cargo and passengers, reflecting the current inertial load level of the vehicle. It can be obtained through real-time estimation or direct detection. The road gradient is the longitudinal slope value of the road surface the vehicle is currently traveling on, characterizing the degree of influence of the gravity component of the slope on the vehicle's braking demand. It can be obtained through dynamic calculation or direct sensor detection. The correction coefficient is composed of the ratio of the current total mass of the vehicle to the unloaded reference mass and the slope correction factor.

[0075] Specifically, the total braking torque required by the driver must satisfy the following formula:

[0076] In the formula, To meet the driver's braking torque requirements, Based on the required braking torque, The current total mass of the vehicle. For reference mass of the vehicle when unloaded. This is the slope correction factor.

[0077] Optionally, the maximum available braking torque of the motor is calculated and determined in real time based on the current speed of the drive motor, the motor temperature, and the state of charge of the power battery; when the state of charge of the power battery is higher than the preset safety threshold, the maximum available braking torque of the motor is limited to be reduced or set to zero to avoid overcharging of the power battery.

[0078] The maximum usable braking torque of the retarder is determined based on the input shaft speed and oil temperature of the retarder.

[0079] The maximum available braking torque of the engine is determined based on the current engine speed and the operating status of the exhaust brake valve or compression release brake.

[0080] Specifically, the maximum available braking torque of the motor is calculated by the motor controller based on the external characteristics of the drive motor, combined with temperature constraints and power battery charging constraints. First, using the current speed of the drive motor as input, the controller queries the motor braking external characteristic mapping relationship, pre-calibrated through bench testing and stored in the controller, to obtain the peak braking torque that the drive motor can output at that speed, serving as the base value for braking capability. This mapping relationship corresponds to the torque output limit of the motor hardware itself, maintaining peak torque below the rated speed and decreasing with increasing speed above the rated speed. Based on this, a motor temperature correction coefficient is introduced to thermally constrain the base value. The motor temperature correction coefficient is pre-calibrated according to changes in motor winding temperature or permanent magnet temperature: when the motor temperature is within the normal operating range, the motor temperature correction coefficient is 1, and braking capability is not limited by temperature; when the motor temperature exceeds a preset first temperature threshold, the motor temperature correction coefficient decreases linearly with increasing temperature, causing the output braking torque to gradually decrease with rising temperature, thereby limiting the motor's heat generation power; when the temperature reaches the highest protection threshold, the motor temperature correction coefficient drops to the lowest protection value. Multiplying the base value of the peak braking torque by the correction coefficient corresponding to the current motor temperature yields the available braking torque under temperature constraints. Simultaneously, a constraint on the charging capacity of the power battery is introduced. The maximum allowable charging power of the power battery is converted into the corresponding braking torque limit at the motor shaft end. The conversion process takes into account the motor's power generation efficiency and the transmission system efficiency. The maximum allowable charging power of the power battery is directly controlled by the state of charge (SOC). When the SOC is within the normal range, the maximum allowable charging power remains at the rated value. When the SOC exceeds a preset first safety threshold, the allowable charging power gradually decreases as the SOC increases. When the SOC exceeds a preset overcharge protection threshold, the allowable charging power is directly set to zero, corresponding to a braking torque limit of zero. Finally, the available braking torque under temperature constraints is compared with the braking torque limit under charging power constraints, and the smaller of the two values ​​is taken as the maximum available braking torque of the motor under the current operating conditions.

[0081] The maximum usable braking torque of the retarder is calculated by the retarder controller based on two core constraints: input shaft speed and operating oil temperature. First, using the current input shaft speed of the hydraulic retarder as input, the pre-calibrated mapping relationship between retarder speed and rated braking torque is consulted to obtain the maximum rated braking torque that the retarder can output at that speed, which serves as the base value for braking capability. The hydraulic retarder generates braking torque through the circulation of working oil between the impellers. In the low-speed range, the rated braking torque gradually increases with the increase of the input shaft speed; once the input shaft speed reaches the rated operating speed range, the rated braking torque remains at the design maximum value and no longer increases with further speed increases. Based on this, an oil temperature correction coefficient is introduced to correct for thermal attenuation of the rated braking torque base value. This coefficient is pre-calibrated according to the retarder's working oil temperature: when the oil temperature is within the normal operating temperature range, the correction coefficient is 1, allowing the retarder to utilize its full rated braking capacity; when the oil temperature exceeds a preset warning temperature threshold, the correction coefficient decreases linearly with increasing oil temperature, corresponding to a gradual decrease in the output braking torque, thus limiting braking power and suppressing further increases in oil temperature; when the oil temperature reaches the maximum protection temperature, the correction coefficient drops to its minimum value to prevent retarder malfunctions such as seal failure and oil deterioration due to sustained high temperatures. Finally, multiplying the rated braking torque base value by the correction coefficient corresponding to the current oil temperature yields the maximum usable braking torque of the retarder under the current operating conditions.

[0082] The maximum available braking torque of the engine is calculated and determined by the engine controller based on the current operating state of the braking mechanism and the engine speed. First, the current operating state of the engine braking mechanism is identified, specifically the activation position of the exhaust brake valve and the compression release brake mechanism. The engine braking mechanism has multiple operating positions, each corresponding to a different braking capacity level: activating only the exhaust brake valve corresponds to a lower braking capacity level, while activating different positions of the compression release brake corresponds to progressively increasing braking capacity levels. Each operating position has a pre-defined engine speed-braking torque characteristic relationship. Then, using the current engine speed as input, the engine speed-braking torque characteristic relationship corresponding to the current operating position is looked up to obtain the basic braking torque at that speed. Engine braking relies on the in-cylinder pumping resistance to dissipate vehicle kinetic energy. Within the effective operating speed range, the higher the engine speed, the stronger the pumping action, and the greater the corresponding basic braking torque. When the engine speed is lower than the minimum activation speed for engine braking, the braking mechanism cannot effectively establish braking torque; at this time, the basic braking torque is set to zero to avoid the risk of engine stalling due to braking load. Finally, the basic braking torque obtained from the lookup table is the maximum available braking torque of the engine under the current operating conditions.

[0083] Optionally, following S130, the following may also be included:

[0084] S140. If the total braking torque of each braking source after distribution is greater than the total braking torque required by the driver, the total braking torque is gradually reduced in the order of first reducing the braking torque of the retarder and then reducing the braking torque of the drive motor, until the total braking torque matches the total braking torque required by the driver.

[0085] Specifically, the vehicle controller first calculates the difference between the currently allocated total braking torque and the total braking torque required by the driver, thus determining the amount of excess torque to be reduced. First, the allocated torque of the hydraulic retarder is lowered. Within the range of the currently allocated braking torque of the hydraulic retarder, its output command value is gradually reduced to offset the excess torque. If the total braking torque is still higher than the driver's requirement after the hydraulic retarder's braking torque is reduced to zero, the regenerative braking torque of the drive motor is further reduced until the total output braking torque of the three braking sources perfectly matches the total braking torque required by the driver.

[0086] This orderly callback mechanism ensures the accuracy of braking torque output, avoids smoothness issues caused by braking intensity exceeding driver expectations, maximizes regenerative braking benefits by prioritizing the reduction of non-energy recovery braking sources, and reduces frequent fluctuations in motor braking torque, which is beneficial to the stability of the power battery charging status and the improvement of battery life.

[0087] Optionally, the braking torque variation rates of the drive motor, retarder, and engine are uniformly controlled based on the maximum value of the braking torque variation within a single cycle of the three components.

[0088] Specifically, during the dynamic distribution of auxiliary braking torque, the vehicle controller updates the target braking torque of each braking source cyclically at a fixed period. Affected by changes in operating conditions, the target braking torque of the drive motor, hydraulic retarder, and engine may increase or decrease relative to the previous period within each control cycle. If the three types of braking sources adjust their output torque independently according to their respective hardware response characteristics, a problem of inconsistent torque changes will occur: the torque of the braking source with a fast response speed will be quickly delivered, while the torque of the braking source with a slow response speed will be output with a lag, resulting in a phased step fluctuation in the total braking torque of the vehicle, which in turn causes vehicle jerking and creates alternating impact loads on the transmission system.

[0089] To address the aforementioned issues, this solution employs a unified rate-of-change control method. Specifically, within each control cycle, the vehicle controller calculates the difference between the target braking torque of the drive motor, hydraulic retarder, and engine in the current cycle and the actual output braking torque of the previous cycle, obtaining the single-cycle braking torque change for each of the three components. Then, the set with the largest value among the three sets of changes is selected as the torque change rate benchmark for all braking sources in this cycle. The drive motor, hydraulic retarder, and engine all synchronously adjust their torque output according to the torque adjustment range corresponding to this unified benchmark, ensuring that the braking torque of the three components changes by the same magnitude within the same cycle, achieving synchronized increases and decreases in torque output.

[0090] Using the maximum value among the three variables as a unified benchmark avoids excessively limiting the overall response speed of the braking system, ensuring that the braking torque can be adjusted in a timely manner according to the driver's gear operation and changes in operating conditions, balancing the timeliness and smoothness of braking response. This unified rate control effectively eliminates the problem of torque asynchrony when multiple braking sources work together, resulting in a stable and linear trend in the total braking torque. This improves driving comfort under continuous braking conditions, reduces fatigue wear on the transmission system caused by alternating torque impacts, and extends the service life of components.

[0091] The following is a specific embodiment to illustrate the auxiliary braking torque distribution method for hybrid heavy-duty vehicles provided by the present invention:

[0092] Step S1: Obtain the driver's auxiliary braking gear signal Gear, with a value range of 1 to N. If the lever is in position 0, no auxiliary braking torque distribution will be performed.

[0093] Step S2: According to the gear and current vehicle speed The basic braking torque requirement can be obtained by looking up the pre-calibrated MAP table. The MAP (Motor Mounting Parameter) chart shows the relationship between vehicle speed and desired braking torque at different gears. Generally, as vehicle speed increases, the required torque initially increases and then tends to stabilize. Subsequently, based on the vehicle's currently estimated total mass... and road slope Through formula In the formula, To meet the driver's braking torque requirements, Based on the required braking torque, The current gross vehicle weight. For the vehicle's unloaded reference mass, This is the slope correction factor; the steeper the downhill slope, the larger the factor.

[0094] Step S3: The vehicle controller obtains the maximum available braking torque that the drive motor can currently provide from the motor controller. This value is determined by the motor's external characteristic torque curve, the current motor speed, the motor temperature, and the battery's available charging power. When the battery's available charging power is low, the maximum available braking torque of the motor is forced to protect the battery. Set the value to 0 or significantly reduce it. Simultaneously, obtain the maximum available braking torque of the retarder from the retarder controller. It is limited by the retarder input shaft speed and oil temperature; the maximum available braking torque of the engine is obtained from the engine controller. It depends on the engine speed.

[0095] Step S4: Perform braking torque priority allocation. First, calculate the motor braking request torque. At this time, if the motor has its maximum available braking torque... ≥ Driver's required total braking torque The demand is entirely met by the motor, and the motor braking torque requirement is... =0, engine braking requested torque =0, jump directly to step S5.

[0096] If this condition is not met, the motor will output its maximum usable torque. Calculate the first remaining demand torque Next, the braking torque requested by the hydraulic retarder is calculated. If the retarder has a maximum available braking torque ≥ First Remaining Required Torque The retarder fully covers the remaining demand, and the engine braking torque is requested. =0.

[0097] If the retarder's capacity is still insufficient, the retarder will output its maximum available torque. Calculate the second remaining demand torque .

[0098] If the braking torque corresponds to 50% of the engine's braking capacity Second remaining demand torque Then the engine braking torque is requested. =Braking torque corresponding to 50% of the engine's braking capacity If the braking torque corresponding to 50% of the engine's braking capacity Second remaining demand torque Engine braking torque request =Braking torque corresponding to 100% engine braking capacity %.

[0099] If the requested engine torque exceeds the engine's maximum available braking torque... If the engine outputs its maximum available braking torque, it will generate an "insufficient auxiliary braking capacity" alarm message, and simultaneously provide the driver with the total braking torque required. The torque is limited to the total braking torque already applied to avoid misjudging the braking intensity by the driver; if the requested engine torque exceeds the total braking torque required by the driver... If the retarder is reduced first, then the braking torque of the electric motor is reduced until the total braking torque required by the driver is met.

[0100] The braking torque variation rates of the drive motor, retarder, and engine are uniformly controlled based on the maximum value of the braking torque variation within a single cycle of the three components.

[0101] Step S5: The vehicle controller will calculate the required motor braking torque. Retarder braking torque request Engine braking torque request The torque is sent to the motor controller, retarder controller, and engine controller respectively, and each controller completes the torque response. Then, the process returns to step S1 to perform the calculation for the next cycle.

[0102] Through the above methods, this solution achieves orderly coordination of multiple braking sources in hybrid commercial vehicles, ensuring safety while achieving better energy recovery.

[0103] Figure 2 This is a schematic diagram of the structure of an auxiliary braking torque distribution device for a hybrid heavy-duty vehicle provided in an embodiment of the present invention. (See attached diagram.) Figure 2 The device includes an acquisition module 210, a calculation module 220, and a control and allocation module 230.

[0104] The acquisition module 210 is used to acquire the vehicle's current auxiliary braking gear, current vehicle speed, maximum available braking torque of the electric motor, maximum available braking torque of the retarder, and maximum available braking torque of the engine.

[0105] The calculation module 220 is used to calculate the total braking torque required by the driver based on the current auxiliary braking gear and the current vehicle speed.

[0106] The control distribution module 230 is used to control the output braking torque of the drive motor, retarder and engine according to the maximum available braking torque of the motor, the maximum available braking torque of the retarder, the maximum available braking torque of the engine and the total braking torque required by the driver, and according to the preset priority braking torque distribution principle.

[0107] The hybrid heavy-duty vehicle auxiliary braking torque distribution device provided in this embodiment of the invention can execute the hybrid heavy-duty vehicle auxiliary braking torque distribution method provided in any embodiment of the invention, and has the corresponding functional modules and beneficial effects of the method.

[0108] Figure 3 This is a schematic diagram of an electronic device for an auxiliary braking torque distribution method for a hybrid heavy-duty vehicle, provided as an embodiment of the present invention. The electronic device is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. The electronic device can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices (e.g., helmets, glasses, watches, etc.), and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0109] like Figure 3 As shown, the electronic device 10 includes at least one processor 11 and a memory, such as a read-only memory (ROM) 12 and a random access memory (RAM) 13, communicatively connected to the at least one processor 11. The memory stores computer programs executable by the at least one processor. The processor 11 can perform various appropriate actions and processes based on the computer program stored in the ROM 12 or loaded into the RAM 13 from storage unit 18. The RAM 13 can also store various programs and data required for the operation of the electronic device 10. The processor 11, the ROM 12, and the RAM 13 are interconnected via a bus 14. An input / output (I / O) interface 15 is also connected to the bus 14.

[0110] Multiple components in electronic device 10 are connected to input / output I / O interface 15, including: input unit 16, such as keyboard, mouse, etc.; output unit 17, such as various types of monitors, speakers, etc.; storage unit 18, such as disk, optical disk, etc.; and communication unit 19, such as network card, modem, wireless transceiver, etc. Communication unit 19 allows electronic device 10 to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks.

[0111] Processor 11 can be a variety of general-purpose and / or special-purpose processing components with processing and computing capabilities. Some examples of processor 11 include, but are not limited to, a central processing unit (CPU), a graphics processing unit (GPU), various special-purpose artificial intelligence (AI) computing chips, various processors running machine learning model algorithms, digital signal processors (DSPs), and any suitable processor, controller, microcontroller, etc. Processor 11 performs the various methods and processes described above, such as a hybrid heavy-duty vehicle auxiliary braking torque distribution method.

[0112] In some embodiments, a hybrid heavy-duty vehicle auxiliary braking torque distribution method may be implemented as a computer program tangibly contained in a computer-readable storage medium, such as storage unit 18. In some embodiments, part or all of the computer program may be loaded and / or installed on electronic device 10 via read-only memory ROM 12 and / or communication unit 19. When the computer program is loaded into random access memory RAM 13 and executed by processor 11, one or more steps of the hybrid heavy-duty vehicle auxiliary braking torque distribution method described above may be performed. Alternatively, in other embodiments, processor 11 may be configured in any other suitable manner to perform a hybrid heavy-duty vehicle auxiliary braking torque distribution method.

[0113] Various embodiments of the systems and techniques described above herein can be implemented in digital electronic circuit systems, integrated circuit systems, field-programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), systems-on-a-chip (SoCs), payload-programmable logic devices (CPLDs), computer hardware, firmware, software, and / or combinations thereof. These various embodiments may include implementations in one or more computer programs that can be executed and / or interpreted on a programmable system including at least one programmable processor, which may be a dedicated or general-purpose programmable processor, capable of receiving data and instructions from a storage system, at least one input device, and at least one output device, and transferring data and instructions to the storage system, the at least one input device, and the at least one output device.

[0114] Computer programs used to implement the methods of the present invention may be written in any combination of one or more programming languages. These computer programs may be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing device, such that when executed by the processor, the computer programs cause the functions / operations specified in the flowcharts and / or block diagrams to be performed. The computer programs may be executed entirely on a machine, partially on a machine, or as a standalone software package, partially on a machine and partially on a remote machine, or entirely on a remote machine or server.

[0115] In the context of this invention, a computer-readable storage medium can be a tangible medium that may contain or store a computer program for use by or in conjunction with an instruction execution system, apparatus, or device. A computer-readable storage medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. Alternatively, a computer-readable storage medium may be a machine-readable signal medium. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0116] To provide interaction with a user, the systems and techniques described herein can be implemented on an electronic device having: a display device for displaying information to a user; and a keyboard and pointing device through which the user provides input to the electronic device. Other types of devices can also be used to provide interaction with a user; for example, feedback provided to the user can be any form of sensory feedback; and input from the user can be received in any form.

[0117] The systems and technologies described herein can be implemented in computing systems that include backend components, middleware components, or frontend components (e.g., a user computer with a graphical user interface or web browser through which a user can interact with implementations of the systems and technologies described herein), or any combination of such backend, middleware, or frontend components. The components of the system can be interconnected via digital data communication of any form or medium. Examples of communication networks include local area networks (LANs), wide area networks (WANs), blockchain networks, and the Internet.

[0118] A computing system can include clients and servers. Clients and servers are generally located far apart and typically interact through communication networks. The client-server relationship is created by computer programs running on the respective computers and having a client-server relationship with each other. The server can be a cloud server, also known as a cloud computing server or cloud host, which is a hosting product within the cloud computing service system to address the shortcomings of traditional physical hosts and VPS services, such as high management difficulty and weak business scalability.

[0119] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0120] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for auxiliary braking torque distribution in a hybrid heavy-duty vehicle, characterized in that, include: Obtain the vehicle's current auxiliary braking gear, current vehicle speed, maximum available braking torque of the electric motor, maximum available braking torque of the retarder, and maximum available braking torque of the engine; Calculate the total braking torque required by the driver based on the current auxiliary braking gear and the current vehicle speed; Based on the maximum available braking torque of the motor, the maximum available braking torque of the retarder, the maximum available braking torque of the engine, and the total braking torque required by the driver, the output braking torque of the drive motor, retarder, and engine is controlled according to a preset priority braking torque allocation principle.

2. The method according to claim 1, characterized in that, The specific principles for pre-defined priority braking torque distribution are as follows: The total braking torque required by the driver is preferentially allocated to the drive motor to perform regenerative braking; if the maximum available braking torque of the motor is less than the total braking torque required by the driver, the drive motor is controlled to output the maximum available braking torque of the motor, and the first remaining required torque is calculated. Distribute the first remaining required torque to the retarder; If the maximum available braking torque of the retarder is less than the first remaining required torque, then control the hydraulic retarder to output the maximum available braking torque of the retarder and calculate the second remaining required torque. The second remaining required torque is distributed to the engine to perform auxiliary braking.

3. The method according to claim 2, characterized in that, After allocating the second remaining required torque to the engine to perform auxiliary braking, the process also includes: If the second remaining required torque is greater than the engine's maximum available braking torque, the engine is controlled to output its maximum available braking torque, while an alarm signal indicating insufficient auxiliary braking capacity is generated and issued, and the total braking torque required by the driver is limited to the currently allocated total braking torque.

4. The method according to claim 2, characterized in that, The process of distributing the second remaining demand torque to the engine includes: The second remaining required torque is compared with the preset engine braking torque; If the preset engine braking torque is greater than or equal to the second remaining required torque, then control the engine to output the preset engine braking torque; If the preset engine braking torque is less than the second remaining required torque, then control the engine to output 100% braking torque.

5. The method according to claim 1, characterized in that, The total braking torque required by the driver is calculated based on the current auxiliary braking gear and the current vehicle speed, including: Based on the preset calibrated gear-vehicle speed-basic required torque mapping table, the basic required braking torque under the corresponding working condition is obtained by looking up the table; Based on the vehicle's current total mass and the road gradient, a correction coefficient is determined, and the basic required braking torque is corrected to obtain the total braking torque required by the driver.

6. The method according to claim 5, characterized in that, The correction factor is composed of the ratio of the vehicle's current total mass to its unloaded reference mass and the slope correction factor. The total braking torque required by the driver satisfies the following formula: In the formula, To meet the driver's braking torque requirements, Based on the required braking torque, The current gross vehicle weight. For the vehicle's unloaded reference mass, This is the slope correction factor.

7. The method according to claim 1, characterized in that, The maximum available braking torque of the motor is calculated and determined in real time based on the current speed of the drive motor, the motor temperature, and the state of charge of the power battery. When the state of charge of the power battery is higher than the preset safety threshold, the maximum available braking torque of the motor is limited to be reduced or set to zero in order to avoid overcharging of the power battery. The maximum available braking torque of the retarder is determined based on the input shaft speed and oil temperature of the retarder. The maximum available braking torque of the engine is determined based on the current engine speed and the operating state of the exhaust brake valve or compression release brake.

8. The method according to claim 1, characterized in that, After controlling the output braking torque of the drive motor, retarder, and engine according to a preset priority braking torque allocation principle based on the maximum available braking torque of the motor, the maximum available braking torque of the retarder, the maximum available braking torque of the engine, and the total braking torque required by the driver, the process further includes: If the total braking torque of all braking sources after allocation is greater than the total braking torque required by the driver, the total braking torque will be gradually reduced in the order of first reducing the braking torque of the retarder and then reducing the braking torque of the drive motor, until the total braking torque matches the total braking torque required by the driver.

9. The method according to claim 1, characterized in that, The braking torque variation rates of the drive motor, retarder, and engine are uniformly controlled based on the maximum value of the braking torque variation within a single cycle of the three components.

10. A hybrid heavy-duty vehicle auxiliary braking torque distribution device, characterized in that, include: The acquisition module is used to acquire the vehicle's current auxiliary braking gear, current vehicle speed, maximum available braking torque of the motor, maximum available braking torque of the retarder, and maximum available braking torque of the engine. The calculation module is used to calculate the total braking torque required by the driver based on the current auxiliary braking gear and the current vehicle speed; The control allocation module is used to control the output braking torque of the drive motor, the retarder, and the engine according to a preset priority braking torque allocation principle based on the maximum available braking torque of the motor, the maximum available braking torque of the retarder, the maximum available braking torque of the engine, and the total braking torque required by the driver.

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