Method, device and equipment for linkage of auxiliary brake and main brake of commercial vehicle and medium

Abstract

The application discloses a kind of auxiliary brake and main brake linkage method, device, equipment and medium of commercial vehicle, is related to auxiliary brake control technical field, method includes: in response to vehicle enters constant speed downhill working condition, the actual vehicle speed, target vehicle speed, road gradient, whole vehicle mass and the working state parameter of auxiliary brake system of vehicle are acquired;According to the deviation of actual vehicle speed and target vehicle speed, road gradient and whole vehicle mass determine whole vehicle braking demand, and according to the working state parameter of auxiliary brake system determines auxiliary brake capacity;When determining that whole vehicle braking demand exceeds auxiliary brake capacity, if actual vehicle speed is greater than target vehicle speed and the relative value between them is greater than first deviation threshold, then control main brake intervention, and then if actual vehicle speed is greater than target vehicle speed and the relative value between them is less than second deviation threshold, then control main brake exit.The application links up main brake to supplement when auxiliary brake capacity is insufficient, and simultaneously realizes the late entry early exit of main brake.

Description

Technical Field

[0001] This application relates to the field of auxiliary braking control technology, specifically to a method, device, equipment, and medium for linking auxiliary braking and main braking in commercial vehicles. Background Technology

[0002] When commercial vehicles are descending long slopes in mountainous or hilly conditions, auxiliary braking is generally used to ensure safe and constant speed descent. Currently, auxiliary braking for commercial vehicles mainly includes hydraulic retarder braking, engine braking, and electric motor braking. Constant speed descent primarily relies on these auxiliary braking devices.

[0003] Currently, most constant-speed downhill control schemes rely solely on the auxiliary braking system to maintain vehicle speed. For vehicles equipped with only engine braking or electric motor braking, the auxiliary braking power is insufficient to independently maintain a constant speed on long downhill slopes in regions like Yunnan, Guizhou, and Sichuan, posing a safety risk of speed loss. Existing technologies lack a control method that can systematically utilize the main braking system to supplement auxiliary braking when its capacity is insufficient, achieving coordinated operation between auxiliary and main braking. When auxiliary braking is insufficient and main braking assistance is needed, triggering and disengagement often rely on a single threshold, or the main braking disengagement logic is not clearly defined. This control method easily leads to frequent intervention and disengagement of the main braking system near the critical point, not only reducing driving smoothness and comfort but also potentially accelerating wear on the main braking system. Summary of the Invention

[0004] This application provides a method, device, equipment, and medium for linking auxiliary braking and main braking of commercial vehicles, which can solve the technical problem of insufficient braking capacity of commercial vehicles in long downhill conditions in the prior art.

[0005] In a first aspect, embodiments of this application provide a method for linking auxiliary braking and main braking of a commercial vehicle, the method comprising: In response to the vehicle entering a constant-speed downhill condition, the system acquires the vehicle's actual speed, target speed, road gradient, vehicle weight, and operating status parameters of the auxiliary braking system. The vehicle braking requirements are determined based on the deviation between the actual vehicle speed and the target vehicle speed, the road gradient, and the overall vehicle weight. The auxiliary braking capacity is determined based on the working status parameters of the auxiliary braking system. When it is determined that the vehicle's braking demand exceeds the auxiliary braking capacity, if the actual vehicle speed is greater than the target vehicle speed and the relative value between the two is greater than the first deviation threshold, the main braking is controlled to intervene. Then, if the actual vehicle speed is greater than the target vehicle speed and the relative value between the two is less than the second deviation threshold, the main braking is controlled to disengage.

[0006] In conjunction with the first aspect, in one embodiment, the auxiliary braking system includes hydraulic retarder braking, engine braking, or electric motor braking.

[0007] In conjunction with the first aspect, in one embodiment, when the auxiliary braking system is a hydraulic retarder brake, the control of the engagement and disengagement of the main brake includes: When the actual vehicle speed is detected to be higher than the target vehicle speed and the relative value between the two is greater than the first threshold, the vehicle engine speed is increased and the coolant flow rate of the hydraulic retarder is increased. The system acquires the actual vehicle speed and target vehicle speed in real time. When the actual vehicle speed is higher than the target vehicle speed and the relative value between the two is greater than the second threshold, the cooling fan speed of the vehicle cooling system is increased. Then, when the actual vehicle speed is higher than the target vehicle speed and the relative value between the two is greater than the third threshold, the main braking intervention is triggered. Then, when the actual vehicle speed is higher than the target vehicle speed and the relative value between the two is less than the second deviation threshold, the main braking intervention is disengaged. The first threshold, the second threshold, and the third threshold increase sequentially, and the second deviation threshold is less than the third threshold.

[0008] In conjunction with the first aspect, in one embodiment: the operating state parameters of the hydraulic retarder braking include the coolant temperature of the hydraulic retarder, and the maximum available braking power of the hydraulic retarder is determined based on the coolant temperature as an auxiliary braking capability.

[0009] In conjunction with the first aspect, in one embodiment, when the auxiliary braking system is engine braking or electric motor braking, the control of main brake engagement and disengagement includes: Real-time acquisition of engine or motor speed, as well as actual vehicle speed; Determine the deviation between the engine or motor speed and the preset speed: When the engine or motor speed exceeds the first preset speed, the main brake is triggered. Then, when the engine or motor speed drops back to the second preset speed, the main brake is disengaged. The first preset speed is greater than the second preset speed. Determine the deviation between the actual vehicle speed and the target vehicle speed: When the actual vehicle speed is greater than the target vehicle speed and the relative value between the two is greater than the first deviation threshold, the main braking intervention is triggered. Afterwards, if the actual vehicle speed is greater than the target vehicle speed and the relative value between the two is less than the second deviation threshold, the main braking intervention is disengaged. The first deviation threshold is greater than the second deviation threshold. During engine braking or electric motor braking, the maximum permissible speed of the engine or motor is controlled to not exceed the third preset speed, and the second preset speed is greater than the third preset speed.

[0010] In conjunction with the first aspect, in one implementation: when the number of main brake interventions exceeds a preset threshold, the maximum speed at which engine braking or electric motor braking is allowed to operate is increased from the third preset speed to a fourth preset speed, wherein the fourth preset speed is less than the first preset speed.

[0011] In conjunction with the first aspect, in one implementation, before controlling the intervention of the main brake based on the auxiliary braking capacity and the vehicle braking demand when the overall vehicle braking demand exceeds the auxiliary braking capacity, the method further includes: When the vehicle enters a constant-speed downhill condition, the auxiliary braking system activates to determine the deviation between the actual vehicle speed and the target vehicle speed. When the actual vehicle speed is higher than the target vehicle speed, the auxiliary braking system continues to operate. When the actual vehicle speed is less than or equal to the target vehicle speed, the auxiliary braking system is disengaged.

[0012] Secondly, embodiments of this application provide an auxiliary braking and main braking linkage device for a commercial vehicle, the auxiliary braking and main braking linkage device for the commercial vehicle comprising: The acquisition module is used to acquire the vehicle's actual speed, target speed, road gradient, vehicle weight, and operating status parameters of the auxiliary braking system in response to the vehicle entering a constant speed downhill condition. The determination module is used to determine the vehicle braking requirements based on the deviation between the actual vehicle speed and the target vehicle speed, the road gradient and the vehicle weight, and to determine the auxiliary braking capacity based on the working status parameters of the auxiliary braking system. The control module is used to determine when the vehicle's braking demand exceeds the auxiliary braking capacity. If the actual vehicle speed is greater than the target vehicle speed and the relative value between the two is greater than the first deviation threshold, the main brake is activated. If the actual vehicle speed is greater than the target vehicle speed and the relative value between the two is less than the second deviation threshold, the main brake is deactivated.

[0013] Thirdly, embodiments of this application provide an auxiliary braking and main braking linkage device for a commercial vehicle. The auxiliary braking and main braking linkage device for a commercial vehicle includes a processor, a memory, and an auxiliary braking and main braking linkage program for a commercial vehicle stored in the memory and executable by the processor. When the auxiliary braking and main braking linkage program for a commercial vehicle is executed by the processor, it implements the steps of the auxiliary braking and main braking linkage method for a commercial vehicle as described in any of the above embodiments.

[0014] Fourthly, embodiments of this application provide a computer-readable storage medium storing a program for linking the auxiliary braking and main braking of a commercial vehicle. When the program is executed by a processor, it implements the steps of the method for linking the auxiliary braking and main braking of a commercial vehicle as described in any of the above embodiments.

[0015] The beneficial effects of the technical solutions provided in this application include: This application embodiment compares the vehicle's braking demand with the auxiliary braking capacity, and supplements the main brake when the auxiliary braking capacity is insufficient, thus solving the problem of insufficient braking capacity of a single auxiliary brake configuration under long downhill conditions. This application embodiment sets different intervention and withdrawal thresholds, ensuring that the main brake only intervenes when the vehicle speed deviation is large and withdraws when the deviation is small, achieving delayed intervention and early withdrawal of the main brake, reducing the intervention time and frequency of the main brake, and lowering wear on the main brake system. This application embodiment requires the actual vehicle speed to be greater than the target vehicle speed and the deviation to exceed a large threshold when the main brake intervenes, and requires the actual vehicle speed to be greater than the target speed and the deviation to be less than a small threshold when withdrawing. This forms hysteresis control of the main brake, avoiding frequent switching of the main brake near the critical point and improving the smoothness of the braking process. Attached Figure Description

[0016] Figure 1 A schematic flowchart illustrating the auxiliary braking and main braking linkage method for commercial vehicles provided in the embodiments of this application; Figure 2 A schematic diagram of the functional modules of the auxiliary braking and main braking linkage device for commercial vehicles provided in the embodiments of this application; Figure 3 This is a schematic diagram of the hardware structure of the auxiliary braking and main braking linkage device for commercial vehicles provided in the embodiments of this application. Detailed Implementation

[0017] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0019] This application provides a method, device, equipment, and medium for linking auxiliary braking and main braking of commercial vehicles, which can solve the technical problem of insufficient braking capacity of commercial vehicles in long downhill conditions in the prior art.

[0020] In a first aspect, embodiments of this application provide a method for linking auxiliary braking and main braking of a commercial vehicle.

[0021] In one embodiment, reference is made to Figure 1, Figure 1 This is a flowchart illustrating the method for linking auxiliary braking and main braking of a commercial vehicle, as provided in an embodiment of this application. Figure 1 As shown, the method for linking the auxiliary braking and main braking of commercial vehicles specifically includes the following steps: Step S1: In response to the vehicle entering a constant speed downhill condition, acquire the vehicle's actual speed, target speed, road gradient, vehicle weight, and operating status parameters of the auxiliary braking system.

[0022] Specifically, when the vehicle driving mode is set to constant speed downhill control mode, the target constant speed set by the driver is read. This speed usually comes from the setting value when the driver puts the auxiliary brake lever in constant speed or the cruise control interface.

[0023] Step S2: Determine the vehicle braking requirements based on the deviation between the actual vehicle speed and the target vehicle speed, the road gradient, and the overall vehicle weight, and determine the auxiliary braking capacity based on the working status parameters of the auxiliary braking system.

[0024] In this embodiment, the deceleration required to eliminate the vehicle speed deviation is determined based on the vehicle speed deviation, the required braking force is calculated in combination with the vehicle mass, and then converted into the required braking power based on the actual vehicle speed. At the same time, the additional braking power corresponding to the downward component of the vehicle's gravity along the slope direction is calculated based on the road gradient. This additional braking power is superimposed with the aforementioned braking power based on the vehicle speed deviation to obtain the vehicle's required braking power.

[0025] The specific operating parameters of the auxiliary braking system vary depending on the type of auxiliary braking system configured in the vehicle. Auxiliary braking systems include hydraulic retarder braking, engine braking, or electric motor braking. If the auxiliary braking system is hydraulic retarder braking, the operating parameters include the coolant temperature of the hydraulic retarder. The maximum available braking power of the hydraulic retarder is determined based on the coolant temperature, serving as the auxiliary braking capacity. If the auxiliary braking system is engine braking, the operating parameters include the real-time engine speed and the current braking torque. The maximum available braking power of the engine braking at the current speed is determined based on the real-time engine speed and the current braking torque, serving as the auxiliary braking capacity. If the auxiliary braking system is electric motor braking, the operating parameters include the real-time speed of the drive motor and the current braking torque. The maximum available braking power of the electric motor braking at the current speed is obtained based on the real-time speed of the drive motor and the current braking torque, serving as the auxiliary braking capacity.

[0026] In this embodiment, the calculation of vehicle braking demand incorporates road gradient and vehicle mass, enabling the required braking power to adaptively adjust with changes in gradient and load, thus avoiding excessively high or low fixed braking demand under different operating conditions and improving the adaptability of constant speed control under operating conditions.

[0027] Step S3: When it is determined that the vehicle braking demand exceeds the auxiliary braking capacity, if the actual vehicle speed is greater than the target vehicle speed and the relative value between the two is greater than the first deviation threshold, then control the main braking to intervene. After that, if the actual vehicle speed is greater than the target vehicle speed and the relative value between the two is less than the second deviation threshold, then control the main braking to disengage.

[0028] In this embodiment of the application, before controlling the intervention of the main brake based on the auxiliary braking capacity and the vehicle braking demand when the overall vehicle braking demand exceeds the auxiliary braking capacity, the method further includes: When the vehicle enters a constant-speed downhill condition, the auxiliary braking system activates to determine the deviation between the actual vehicle speed and the target vehicle speed. When the actual vehicle speed is higher than the target vehicle speed, the auxiliary braking system continues to operate. When the actual vehicle speed is less than or equal to the target vehicle speed, the auxiliary braking system is disengaged.

[0029] It should be understood that when the vehicle enters a constant-speed downhill condition and the overall vehicle braking demand has not exceeded the auxiliary braking capacity, the auxiliary braking system operates independently, and the vehicle controller continuously judges the deviation between the actual vehicle speed and the target vehicle speed. When the actual vehicle speed is higher than the target vehicle speed, the auxiliary braking system is controlled to continuously output braking torque; when the actual vehicle speed drops to less than or equal to the target vehicle speed, the auxiliary braking system is controlled to disengage to avoid over-braking that would cause the vehicle speed to fall below the target value. When step S2 determines that the overall vehicle braking demand exceeds the auxiliary braking capacity, the main braking linkage control is initiated, the main braking system is activated, and the vehicle controller compares the deviation between the actual vehicle speed and the target vehicle speed to determine whether the main braking intervention conditions are met. The main braking system can be the vehicle's service brakes.

[0030] The activation conditions for the main braking system include: throttle opening is 0; vehicle speed exceeds a certain threshold (calibrable, preset to 15 km / h); constant speed mode is activated (driver activates constant speed mode switch, cruise control, intelligent driving, etc., requesting constant speed downhill); vehicle braking demand exceeds auxiliary braking capacity; the current electronic braking system can respond to constant speed braking requests and call up the main braking; and vehicle speed and electronic braking system request message signals are valid. The main braking system is activated when all of the above conditions are met.

[0031] In one specific embodiment, when the auxiliary braking system is a hydraulic retarder brake, the control of the main brake engagement and disengagement includes: When the actual vehicle speed is detected to be higher than the target vehicle speed and the relative value between the two is greater than the first threshold, the vehicle engine speed is increased and the coolant flow rate of the hydraulic retarder is increased. The system acquires the actual vehicle speed and target vehicle speed in real time. When the actual vehicle speed is higher than the target vehicle speed and the relative value between the two is greater than the second threshold, the cooling fan speed of the vehicle cooling system is increased. Then, when the actual vehicle speed is higher than the target vehicle speed and the relative value between the two is greater than the third threshold, the main braking intervention is triggered. Then, when the actual vehicle speed is higher than the target vehicle speed and the relative value between the two is less than the second deviation threshold, the main braking intervention is disengaged. The first, second, and third thresholds increase sequentially, with the second deviation threshold being less than the third threshold. The relative value should be understood as the absolute value of the difference between the actual vehicle speed and the target vehicle speed.

[0032] Specifically, when the auxiliary braking system is a hydraulic retarder, the vehicle controller adopts a step-by-step intervention strategy after determining that the vehicle's braking demand exceeds the auxiliary braking capacity.

[0033] First, when the actual vehicle speed is higher than the target vehicle speed and the relative value between the two is greater than a first threshold, the vehicle controller sends a downshift request to the transmission control unit to increase the engine speed, thereby increasing the coolant pump drive flow and improving the heat dissipation capacity of the hydraulic retarder cooling circuit. Specifically, this involves increasing the engine speed to above 1600 rpm, with the first threshold being 1.5 km / h.

[0034] Then, when the actual vehicle speed is higher than the target vehicle speed and the relative value between the two further increases to exceed the second threshold, the vehicle controller sends a request to the engine control unit to increase the fan speed, thereby increasing the cooling fan speed and enhancing heat dissipation. At the same time, the power consumed by the fan rotation is used to generate an auxiliary braking effect. The second threshold can specifically be 2.0 km / h.

[0035] Subsequently, when the actual vehicle speed exceeds the target vehicle speed and the relative value between the two further increases to exceed the third threshold, it indicates that the auxiliary braking capability still does not meet the vehicle's braking requirements after the aforementioned two levels of intervention. The vehicle controller then sends a main braking intervention request to the electronic braking system, which triggers the main braking intervention. Specifically, the third threshold can be 2.5 km / h.

[0036] After the main brakes are engaged, the vehicle controller continuously monitors the vehicle speed deviation. When the actual vehicle speed drops below the target speed and the deviation is less than the second deviation threshold, it sends a main brake disengagement request to the electronic braking system to disengage the main brakes.

[0037] During the entire control process, once the actual vehicle speed is detected to be less than or equal to the target vehicle speed, the main braking intervention is disengaged.

[0038] The first, second, and third thresholds increase sequentially, with the second deviation threshold being less than the third threshold. This ensures that the main brake engages when the deviation is large and disengages when the deviation is small, thus forming hysteresis control. In this embodiment, the auxiliary braking system operates independently with priority, only requesting main brake engagement when its capacity is insufficient. This fully utilizes the continuous braking capability of the hydraulic retarder, reducing the frequency of main brake use and wear. The main brake engagement employs hysteresis control, with the engagement threshold greater than the disengagement threshold, avoiding frequent switching of the main brake near critical deviations and improving braking smoothness and driving comfort during constant-speed downhill driving.

[0039] In another specific embodiment, when the auxiliary braking system is engine braking or electric motor braking, the control of main brake engagement and disengagement includes: Real-time acquisition of engine or motor speed, as well as actual vehicle speed; Determine the deviation between the engine or motor speed and the preset speed: When the engine or motor speed exceeds the first preset speed, the main brake is triggered. Then, when the engine or motor speed drops back to the second preset speed, the main brake is disengaged. The first preset speed is greater than the second preset speed. Determine the deviation between the actual vehicle speed and the target vehicle speed: When the actual vehicle speed is greater than the target vehicle speed and the relative value between the two is greater than the first deviation threshold, the main brake is triggered. Then, if the actual vehicle speed is greater than the target vehicle speed and the relative value between the two is less than the second deviation threshold, the main brake is deactivated. The first deviation threshold is greater than the second deviation threshold. During engine braking or electric motor braking, the maximum permissible speed of the engine or motor is controlled to not exceed the third preset speed, and the second preset speed is greater than the third preset speed.

[0040] Specifically, when the auxiliary braking system is engine braking or electric motor braking, the vehicle controller, after determining that the vehicle's braking demand exceeds the auxiliary braking capacity, implements main braking intervention control based on two paths: engine speed overspeed and vehicle speed deviation. Engine speed overspeed triggering has higher priority than vehicle speed deviation triggering. That is, when the triggering conditions for both paths are met simultaneously, the request from the engine speed overspeed path is responded to first, thereby avoiding a sudden drop in upshift braking power and a decrease in reliability due to overspeed, ensuring safety during constant-speed downhill driving.

[0041] When engine braking or electric motor braking is operating independently and the main braking has not yet been triggered, the vehicle controller limits the maximum permissible operating speed of the engine or electric motor to a third preset speed to reduce engine braking noise and improve driving comfort. The third preset speed can be 1800 rpm.

[0042] The vehicle controller acquires the current speed of the engine or drive motor in real time. When the engine or motor speed exceeds a first preset speed, the main braking is triggered. The requested deceleration is determined based on the current road gradient; the steeper the gradient, the greater the absolute value of the requested deceleration. After the main braking is initiated, the speed is continuously monitored. When the engine or motor speed drops to a second preset speed, the main braking is disengaged. The first preset speed is greater than the second preset speed, and the second preset speed is greater than the third preset speed. The first preset speed can be determined based on the engine displacement in actual application; the larger the engine displacement, the lower the first preset speed. Specifically, the first preset speed can be 2300 rpm. The second preset speed can be 1900 rpm.

[0043] Furthermore, when the number of main braking interventions exceeds a preset threshold, the maximum permissible operating speed for engine braking or electric motor braking is increased from the third preset speed to the fourth preset speed. The fourth preset speed is lower than the first preset speed and higher than the second preset speed. This releases the braking potential in the high-speed range, enhances the reserve of auxiliary braking capacity, reduces the number of subsequent main braking interventions, and extends the life of the friction brakes. The fourth preset speed can be between 2000 rpm and 2200 rpm, and can be determined based on engine characteristics; the larger the engine displacement, the narrower the high-speed range.

[0044] Simultaneously, the vehicle controller continuously compares the actual vehicle speed with the target vehicle speed. When the actual vehicle speed is greater than the target vehicle speed and the relative value between the two is greater than a first deviation threshold, the main braking intervention is triggered, requesting the deceleration magnitude of the main braking to be determined based on the target vehicle speed and the speed deviation mapping. Subsequently, if the actual vehicle speed is greater than the target vehicle speed and the relative value between the two is less than a second deviation threshold, the main braking intervention is disengaged. The first deviation threshold is greater than the second deviation threshold. In this embodiment, the first deviation threshold can be 3 km / h, and the second deviation threshold can be 2 km / h. This achieves delayed intervention and early disengagement of the main braking system.

[0045] This application embodiment compares the vehicle's braking demand with the auxiliary braking capacity, and supplements the main brake when the auxiliary braking capacity is insufficient, thus solving the problem of insufficient braking capacity of a single auxiliary brake configuration under long downhill conditions. This application embodiment sets different intervention and withdrawal thresholds, ensuring that the main brake only intervenes when the vehicle speed deviation is large and withdraws when the deviation is small, achieving delayed intervention and early withdrawal of the main brake, reducing the intervention time and frequency of the main brake, and lowering wear on the main brake system. This application embodiment requires the actual vehicle speed to be greater than the target vehicle speed and the deviation to exceed a large threshold when the main brake intervenes, and requires the actual vehicle speed to be greater than the target speed and the deviation to be less than a small threshold when withdrawing. This forms hysteresis control of the main brake, avoiding frequent switching of the main brake near the critical point and improving the smoothness of the braking process.

[0046] In another embodiment of this application, when the driver is detected to have pressed the brake pedal, the vehicle controller calculates the required braking power for engine braking linkage, specifically as follows: Calculate the base power required for engine braking linkage:

[0047] in, This indicates the basic power required for engine braking linkage. Indicates the first quality coefficient. 0.65 × actual mass / full load mass of the vehicle This represents the second slope coefficient. 0.35 × actual slope / maximum slope. The maximum slope of the road is defined as 10%-20%, determined based on the vehicle operation route. This represents the reference power, which is specifically the braking power corresponding to the vehicle's braking when it is fully loaded, descending a slope at a preset speed with a preset maximum gradient, and generating a preset deceleration.

[0048] Calculate the correction factor:

[0049] in, This represents the correction factor. Indicates the vehicle speed coefficient. This indicates the current deceleration. The speed coefficient increases as the actual vehicle speed increases; the greater the deceleration, the smaller the correction coefficient.

[0050] Calculate the braking power required for engine braking linkage:

[0051] in, Indicates the required braking power. This represents the engine braking capability correction factor, determined based on the brake pedal opening. The larger the pedal opening, the better. The smaller, This indicates the engine's maximum braking capacity, which is determined based on the engine's real-time speed. The higher the speed, the greater the engine's braking capacity, representing the maximum braking power that the engine braking system can output at the current engine speed.

[0052] The larger value between the required braking power and the braking power calculated by the normal PID controller is taken as the final braking power to be executed, and the engine braking is controlled to intervene.

[0053] When the driver applies the brakes, the engine braking does not disengage and continues to provide auxiliary braking. At the same time, the correction coefficient limits the amount of braking force to prevent the engine braking and main braking from being too superimposed, which would result in excessive total braking force. This prevents excessive deceleration during braking and ensures braking safety.

[0054] Furthermore, under constant speed downhill conditions, when the main brake disengages due to the vehicle speed deviation falling back to the disengagement threshold, the engine brake does not immediately disengage but continues to operate after a delay. Specifically: Calculate the delay time: Delay time = Baseline delay time × Vehicle speed coefficient / (1 + Delay speed factor × Vehicle speed deviation); Among them, the reference delay time is a preset fixed value; the vehicle speed coefficient increases with the increase of the actual vehicle speed; the vehicle speed deviation is the target vehicle speed minus the actual vehicle speed, and the larger the deviation, the shorter the delay time.

[0055] After the delay period ends, the engine braking demand is calculated again according to the conventional strategy. The larger value is taken as the final braking power to be executed, and the engine braking intervention is continued.

[0056] After the main brake is disengaged, the engine brake disengages with a delay to prevent the auxiliary braking capacity from being completely removed instantly, which would cause the vehicle speed to rise too quickly again. This fills the transition period of braking capacity between the disengagement of the main brake and the independent adjustment of the auxiliary brake, reduces the frequent intervention of the main brake, and improves the continuity and stability of constant speed downhill control.

[0057] In another embodiment of this application, when the actual vehicle speed is detected to be lower than the target vehicle speed, the vehicle controller sets a target acceleration, calculates the braking power requirement based on the difference between the target acceleration and the actual vehicle acceleration, and controls the auxiliary braking to intervene accordingly, so that the vehicle slowly recovers to the target vehicle speed with a controlled lower acceleration, rather than accelerating rapidly under the action of gravity.

[0058] Specifically, first calculate the basic target acceleration: Baseline target acceleration = baseline acceleration - first weighting coefficient × (current road gradient / preset maximum gradient) - second weighting coefficient × (current vehicle mass / full load mass); The baseline acceleration is a preset value; the greater the proportion of road gradient, the smaller the baseline target acceleration; the greater the proportion of vehicle mass, the smaller the baseline target acceleration. That is, the steeper the slope and the heavier the vehicle, the slower the permissible natural acceleration.

[0059] Next, calculate the speed deviation correction factor. The speed deviation correction factor is determined based on the range of the difference between the target speed and the actual speed: when the difference is less than or equal to the upper limit of the first deviation range, the correction factor is the first correction value; when the difference is greater than the upper limit of the first deviation range and less than or equal to the upper limit of the second deviation range, the correction factor is the second correction value; when the difference is greater than the upper limit of the second deviation range and less than or equal to the upper limit of the third deviation range, the correction factor is the third correction value; and when the difference is greater than the upper limit of the third deviation range, the correction factor is the fourth correction value. The correction factor increases progressively with increasing speed deviation; that is, the greater the actual speed is lower than the target speed, the closer the allowed target acceleration is to the basic target acceleration.

[0060] Next, the target acceleration is calculated: target acceleration = basic target acceleration × vehicle speed deviation correction coefficient.

[0061] The braking power requirement is calculated based on the target acceleration. Braking power requirement = vehicle mass × (actual acceleration - target acceleration) × actual vehicle speed.

[0062] Based on the calculated braking power demand, the vehicle controller controls the auxiliary braking system to intervene and provide appropriate braking in the range where the vehicle speed is lower than the target speed, so that the vehicle can gradually accelerate to the constant target speed with the target acceleration, avoiding rapid acceleration.

[0063] When the actual vehicle speed recovers to a level greater than or equal to the target vehicle speed, exit this control logic and switch back to the regular constant speed braking control process.

[0064] Secondly, embodiments of this application also provide an auxiliary braking and main braking linkage device for commercial vehicles.

[0065] In one embodiment, reference is made to Figure 2 , Figure 2 This is a functional module diagram of the auxiliary braking and main braking linkage device for a commercial vehicle provided in an embodiment of this application. Figure 2 As shown, the auxiliary braking and main braking linkage device for commercial vehicles includes: The acquisition module is used to acquire the vehicle's actual speed, target speed, road gradient, vehicle weight, and operating status parameters of the auxiliary braking system in response to the vehicle entering a constant speed downhill condition. The determination module is used to determine the vehicle braking requirements based on the deviation between the actual vehicle speed and the target vehicle speed, the road gradient and the vehicle weight, and to determine the auxiliary braking capacity based on the working status parameters of the auxiliary braking system. The control module is used to determine when the vehicle's braking demand exceeds the auxiliary braking capacity. If the actual vehicle speed is greater than the target vehicle speed and the relative value between the two is greater than the first deviation threshold, the main brake is activated. If the actual vehicle speed is greater than the target vehicle speed and the relative value between the two is less than the second deviation threshold, the main brake is deactivated.

[0066] The functions of each module in the above-mentioned auxiliary braking and main braking linkage device for commercial vehicles correspond to the steps in the above-mentioned auxiliary braking and main braking linkage method embodiment for commercial vehicles. Their functions and implementation processes will not be described in detail here.

[0067] Thirdly, embodiments of this application provide an auxiliary braking and main braking linkage device for a commercial vehicle. The auxiliary braking and main braking linkage device for a commercial vehicle can be a personal computer (PC), laptop computer, server, or other device with data processing capabilities.

[0068] Figure 3 This is a schematic diagram of the hardware structure of an auxiliary braking and main braking linkage device for a commercial vehicle provided in an embodiment of this application. In this embodiment, the auxiliary braking and main braking linkage device for a commercial vehicle may include a processor, a memory, a communication interface, and a communication bus.

[0069] The auxiliary braking and main braking linkage device for commercial vehicles includes a processor, a memory, and an auxiliary braking and main braking linkage program for commercial vehicles stored in the memory and executable by the processor. When the auxiliary braking and main braking linkage program for commercial vehicles is executed by the processor, it implements the steps of the auxiliary braking and main braking linkage method for commercial vehicles as described in any of the above embodiments.

[0070] In this embodiment of the application, the auxiliary braking and main braking linkage device of a commercial vehicle may include a processor, a memory, a communication interface, and a communication bus.

[0071] The communication bus can be of any type and is used to interconnect the processor, memory, and communication interface.

[0072] The communication interface includes input / output (I / O) interfaces, physical interfaces, and logical interfaces used to interconnect components within the auxiliary braking and main braking linkage system of commercial vehicles, as well as interfaces used to interconnect the auxiliary braking and main braking linkage system of commercial vehicles with other devices (such as other computing devices or user equipment). Physical interfaces can be Ethernet interfaces, fiber optic interfaces, ATM interfaces, etc.; user equipment can be displays, keyboards, etc.

[0073] Memory can be various types of storage media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), flash memory, optical storage, hard disk, programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), etc.

[0074] The processor can be a general-purpose processor, which can call the auxiliary braking and main braking linkage program of the commercial vehicle stored in the memory and execute the auxiliary braking and main braking linkage method of the commercial vehicle provided in the embodiments of this application. For example, the general-purpose processor can be a central processing unit (CPU). The method executed when the auxiliary braking and main braking linkage program of the commercial vehicle is called can refer to the various embodiments of the auxiliary braking and main braking linkage method of the commercial vehicle in this application, and will not be repeated here.

[0075] Fourthly, embodiments of this application provide a computer-readable storage medium storing a program for linking the auxiliary braking and main braking of a commercial vehicle. When the program is executed by a processor, it implements the steps of the method for linking the auxiliary braking and main braking of a commercial vehicle as described in any of the above embodiments.

[0076] The present application provides a computer-readable storage medium storing a program for linking the auxiliary braking and main braking of a commercial vehicle. When the program is executed by a processor, it implements the steps of the above-described method for linking the auxiliary braking and main braking of a commercial vehicle.

[0077] The method for implementing the auxiliary braking and main braking linkage procedure of commercial vehicles when it is executed can be referred to in the various embodiments of the auxiliary braking and main braking linkage method of commercial vehicles in this application, and will not be repeated here.

[0078] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0079] The terms "comprising" and "having," and any variations thereof, in the specification, claims, and accompanying drawings of this application are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units not listed, or may optionally include other steps or units inherent to such process, method, product, or apparatus. The terms "first," "second," and "third," etc., are used to distinguish different objects, etc., and do not indicate a sequence, nor do they limit "first," "second," and "third" to different types.

[0080] In the description of the embodiments of this application, terms such as "exemplary," "for example," or "for instance" are used to indicate examples, illustrations, or explanations. Any embodiment or design described as "exemplary," "for example," or "for instance" in the embodiments of this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "exemplary," "for example," or "for instance" is intended to present the relevant concepts in a concrete manner.

[0081] In the description of the embodiments of this application, unless otherwise stated, " / " means "or". For example, A / B can mean A or B. The "and / or" in the text is merely a description of the relationship between related objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist simultaneously, and B exists alone. In addition, in the description of the embodiments of this application, "multiple" means two or more.

[0082] In some processes described in the embodiments of this application, multiple operations or steps are included in a specific order. However, it should be understood that these operations or steps may not be executed in the order they appear in the embodiments of this application, or they may be executed in parallel. The sequence number of the operation is only used to distinguish different operations, and the sequence number itself does not represent any execution order. In addition, these processes may include more or fewer operations, and these operations or steps may be executed sequentially or in parallel, and these operations or steps may be combined.

[0083] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the methods described in the various embodiments of this application.

[0084] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for linking auxiliary braking and main braking in a commercial vehicle, characterized in that, The method for linking the auxiliary braking and main braking of the commercial vehicle includes: In response to the vehicle entering a constant-speed downhill condition, the system acquires the vehicle's actual speed, target speed, road gradient, vehicle weight, and operating status parameters of the auxiliary braking system. The vehicle braking requirements are determined based on the deviation between the actual vehicle speed and the target vehicle speed, the road gradient, and the overall vehicle weight. The auxiliary braking capacity is determined based on the working status parameters of the auxiliary braking system. When it is determined that the vehicle's braking demand exceeds the auxiliary braking capacity, if the actual vehicle speed is greater than the target vehicle speed and the relative value between the two is greater than the first deviation threshold, the main braking is controlled to intervene. Then, if the actual vehicle speed is greater than the target vehicle speed and the relative value between the two is less than the second deviation threshold, the main braking is controlled to disengage.

2. The method for linking auxiliary braking and main braking of a commercial vehicle according to claim 1, characterized in that, The auxiliary braking system includes hydraulic retarder braking, engine braking, or electric motor braking.

3. The method for linking auxiliary braking and main braking of a commercial vehicle according to claim 2, characterized in that, When the auxiliary braking system is a hydraulic retarder brake, the control of the main brake engagement and disengagement includes: When the actual vehicle speed is detected to be higher than the target vehicle speed and the relative value between the two is greater than the first threshold, the vehicle engine speed is increased and the coolant flow rate of the hydraulic retarder is increased. The system acquires the actual vehicle speed and target vehicle speed in real time. When the actual vehicle speed is higher than the target vehicle speed and the relative value between the two is greater than the second threshold, the cooling fan speed of the vehicle cooling system is increased. Then, when the actual vehicle speed is higher than the target vehicle speed and the relative value between the two is greater than the third threshold, the main braking intervention is triggered. Then, when the actual vehicle speed is higher than the target vehicle speed and the relative value between the two is less than the second deviation threshold, the main braking intervention is disengaged. The first threshold, the second threshold, and the third threshold increase sequentially, and the second deviation threshold is less than the third threshold.

4. The method for linking auxiliary braking and main braking of a commercial vehicle according to claim 2, characterized in that: The operating parameters of the hydraulic retarder braking include the coolant temperature of the hydraulic retarder. The maximum available braking power of the hydraulic retarder is determined based on the coolant temperature, which serves as the auxiliary braking capability.

5. The method for linking auxiliary braking and main braking of a commercial vehicle according to claim 2, characterized in that, When the auxiliary braking system is engine braking or electric motor braking, the control of main brake engagement and disengagement includes: Real-time acquisition of engine or motor speed, as well as actual vehicle speed; Determine the deviation between the engine or motor speed and the preset speed: When the engine or motor speed exceeds the first preset speed, the main brake is triggered. Then, when the engine or motor speed drops back to the second preset speed, the main brake is disengaged. The first preset speed is greater than the second preset speed. Determine the deviation between the actual vehicle speed and the target vehicle speed: When the actual vehicle speed is greater than the target vehicle speed and the relative value between the two is greater than the first deviation threshold, the main braking intervention is triggered. Afterwards, if the actual vehicle speed is greater than the target vehicle speed and the relative value between the two is less than the second deviation threshold, the main braking intervention is disengaged. The first deviation threshold is greater than the second deviation threshold. During engine braking or electric motor braking, the maximum permissible speed of the engine or motor is controlled to not exceed the third preset speed, and the second preset speed is greater than the third preset speed.

6. The method for linking auxiliary braking and main braking of a commercial vehicle according to claim 5, characterized in that: When the number of main brake interventions exceeds a preset threshold, the maximum speed at which engine braking or electric motor braking is allowed to operate is increased from the third preset speed to the fourth preset speed, where the fourth preset speed is less than the first preset speed.

7. The method for linking auxiliary braking and main braking of a commercial vehicle according to claim 5, characterized in that, Before controlling the intervention of the main brake based on the relationship between the auxiliary braking capacity and the vehicle's braking demand when the overall vehicle braking demand exceeds the auxiliary braking capacity, the following steps are also included: When the vehicle enters a constant-speed downhill condition, the auxiliary braking system activates to determine the deviation between the actual vehicle speed and the target vehicle speed. When the actual vehicle speed is higher than the target vehicle speed, the auxiliary braking system continues to operate. When the actual vehicle speed is less than or equal to the target vehicle speed, the auxiliary braking system is disengaged.

8. A linkage device for auxiliary braking and main braking of a commercial vehicle, characterized in that, The auxiliary braking and main braking linkage device of the commercial vehicle includes: The acquisition module is used to acquire the vehicle's actual speed, target speed, road gradient, vehicle weight, and operating status parameters of the auxiliary braking system in response to the vehicle entering a constant speed downhill condition. The determination module is used to determine the vehicle braking requirements based on the deviation between the actual vehicle speed and the target vehicle speed, the road gradient and the vehicle weight, and to determine the auxiliary braking capacity based on the working status parameters of the auxiliary braking system. The control module is used to determine when the vehicle's braking demand exceeds the auxiliary braking capacity. If the actual vehicle speed is greater than the target vehicle speed and the relative value between the two is greater than the first deviation threshold, the main brake is activated. If the actual vehicle speed is greater than the target vehicle speed and the relative value between the two is less than the second deviation threshold, the main brake is deactivated.

9. A linkage device for auxiliary braking and main braking of a commercial vehicle, characterized in that, The auxiliary braking and main braking linkage device of the commercial vehicle includes a processor, a memory, and an auxiliary braking and main braking linkage program of the commercial vehicle stored in the memory and executable by the processor, wherein when the auxiliary braking and main braking linkage program of the commercial vehicle is executed by the processor, the steps of the auxiliary braking and main braking linkage method of the commercial vehicle as described in any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a program for linking the auxiliary braking and main braking of a commercial vehicle, wherein when the program for linking the auxiliary braking and main braking of the commercial vehicle is executed by a processor, the steps of the method for linking the auxiliary braking and main braking of a commercial vehicle as described in any one of claims 1 to 7 are implemented.

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