A three-wheel separated hub motor range extending temperature control method and system

Abstract

The application relates to a range-extending electric tricycle temperature control method and system, which belongs to the temperature control technical field of the range-extending electric tricycle, and the method is cyclically executed by a controller according to a control period: a battery state of charge, a heat demand parameter and a power parameter are collected, and vehicle power surplus is calculated; an available heat supply power upper limit, a battery preheating guarantee power and various heat demands are determined; a hierarchical heat supply strategy is executed according to comparison between the vehicle power surplus and a preset threshold value, the battery preheating demand is preferentially met by the range extender waste heat, the balance is supplied to the cab heating, the insufficient part is supplemented by electric heating, when the balance is narrowed, the electric heating power is first reduced, then the heating heat supply is reduced, and the heat obtained by the battery preheating is always not lower than the guarantee power; finally, the range extender start-stop and output power, the valve group opening degree and the circulating pump rotating speed are controlled, and the cycle is cyclically executed. Without increasing hardware, the application avoids the situation that the vehicle is limited to run or even stops and lies in a parking lot caused by the existing heat supply control logic.

Description

Technical Field

[0001] This invention relates to the field of temperature control technology for range-extended electric tricycles, specifically to a method and system for temperature control of a three-wheeled, separate hub motor for range extension. Background Technology

[0002] Electric tricycles are widely used as an important means of transportation for short-distance passenger transport, logistics, and agricultural operations due to their flexibility, light weight, and low operating costs. However, these range-extended electric tricycles face complex and variable working conditions when operating outdoors. As an economy-oriented product, the vehicle's hardware costs are strictly constrained, making it impossible to configure a large number of dedicated redundant hardware components. When used in cold northern regions, the vehicle simultaneously generates multiple intertwined temperature control demands, such as battery preheating and cab heating. Existing heating control logic can easily lead to vehicle restrictions or even complete shutdown. In agricultural freight scenarios that require continuous operation, battery depletion and unexpected vehicle shutdowns will directly interfere with operations, reducing vehicle reliability and user experience under cold outdoor conditions, making it difficult to meet the actual usage needs of economy-oriented agricultural freight tricycles. Summary of the Invention

[0003] The purpose of this invention is to address the complex temperature control needs of economical range-extended electric tricycles in cold northern regions, where battery preheating and cab heating are intertwined and concurrent, under conditions of strict constraints on vehicle hardware costs and the inability to configure a large number of dedicated redundant hardware. This invention provides a three-wheel-separated hub motor range-extended temperature control method and system to improve existing heating control logic, avoid vehicle restrictions or even direct shutdowns, and thus prevent interference from battery depletion and unexpected vehicle shutdowns on continuous operation in low temperatures, thereby improving vehicle reliability and user experience in cold outdoor conditions.

[0004] The technical solution of the present invention is as follows: This invention provides a three-wheel split hub motor range extender temperature control method, which is executed cyclically by a controller according to a control cycle. Each control cycle includes the following steps: S1. Collect vehicle thermal demand parameters and power parameters, and calculate vehicle power margin; The heat demand parameters include battery temperature, cab temperature, and cab heating signal. The power parameters include at least the battery state of charge, the maximum allowable battery discharge power, the range extender power generation, the vehicle drive demand power, and the power of vehicle accessories. The vehicle power margin equals the sum of the range extender's generating power and the battery's maximum allowable discharge power, minus the sum of the vehicle's driving power requirement and the vehicle's accessory power. S2. Based on the vehicle's power margin, determine the upper limit of available heating power and the guaranteed power for battery preheating, and determine the battery preheating requirements and cab heating requirements based on the heat demand parameters. S3. Implement the corresponding tiered heating strategy according to the following judgments: When the vehicle's power margin is greater than or equal to the first preset threshold, the first heating strategy is implemented: the waste heat generated by the range extender is used to supply the battery preheating needs first, and then the waste heat margin is used to supply the cab heating needs. The insufficient part is supplemented by electric heating, and the electric heating power does not exceed the upper limit of the available heating power. When the second preset threshold ≤ vehicle power margin < the first preset threshold, the second heating strategy is executed: reduce the output power of electric heating, retain the heat supply corresponding to the battery preheating demand, and the heat obtained by the battery preheating demand is not less than the heat corresponding to the battery preheating guarantee power. When the vehicle's power margin is less than the second preset threshold, the third heating strategy will be implemented: reduce the heat and power corresponding to the heating demand of the cab, prioritize the heat supply for the battery preheating demand, and ensure that the heat obtained by the battery preheating demand is not less than the heat corresponding to the battery preheating guarantee power. Where the first preset threshold is greater than the second preset threshold; S4. Based on the heating strategy determined in S3, control the start-stop and output power of the range extender according to the battery state of charge, heat demand parameters and vehicle power margin, and control the opening degree of the thermal circuit valve group and the speed of the circulating pump. After completing this cycle, return to S1 to enter the next control cycle for repeated execution.

[0005] In step S3, the waste heat generated by the range extender includes exhaust waste heat and coolant waste heat. When supplying heat, the heat sources are used in order of increasing cost per unit of heat: exhaust waste heat, coolant waste heat and electric heating.

[0006] In step S2, the battery preheating requirement is determined in segments according to battery temperature. The preheating target temperature increases with the increase of battery state of charge and decreases with the increase of vehicle driving power demand. The preheating target temperature is not lower than the battery discharge threshold temperature.

[0007] Step S3 also includes a fourth heating strategy: when the vehicle power margin is less than the third preset threshold and the battery temperature is still below the discharge threshold temperature, the vehicle drive power is limited to the preset limp power limit and the range extender is forcibly started so that the vehicle maintains mobility in limp mode, and the third preset threshold is less than the second preset threshold.

[0008] In step S4, the range extender is triggered to start and stop by the battery state of charge, battery preheating requirements, or cab heating requirements. When the estimated downtime exceeds the preset time, the circulating medium is heated to the upper limit of heat storage temperature before the range extender stops, and the circulating pump is run for a delay after the stop to recover residual heat.

[0009] In step S2, the thermal demand parameters also include the windshield temperature and the humidity inside the cab. The thermal demand also includes the windshield defrosting and defogging demand, and its default priority is between the battery preheating demand and the cab heating demand. Based on the windshield temperature and cabin humidity, determine whether there is a risk of fogging or frost. If so, temporarily update the priority of windshield defrosting and defogging needs to the highest priority within the current control cycle, and input the updated priority into step S3 to participate in the heating strategy allocation.

[0010] In step S2, the heat demand also includes the preheating demand of at least one of the separate hub motor and the reduction mechanism. In step S3, while distributing heat to meet the preheating demand, a torque limiting command is output to limit the peak torque of the separate hub motor during the preheating process.

[0011] The power parameters also include vehicle feedback power. In step S3, when allocating the heating strategy, if the feedback power exceeds the battery's acceptable power, the excess portion will be converted into heat and incorporated into the available heat source for heating.

[0012] While collecting parameters in step S1, abnormal operating condition detection is performed. When at least one of the following abnormalities is detected: circulation pump failure, range extender start failure, battery heat warning, or CO exceeding the limit in the cab, the current control cycle skips the graded heating strategy of S3 and enters the corresponding degraded heating mode. When CO exceeding the limit in the cab is detected, the degraded heating mode includes at least stopping the air supply to the cab and shutting down the range extender.

[0013] The present invention also provides a three-wheeled separate hub motor range extender temperature control system for executing the above-described three-wheeled separate hub motor range extender temperature control method, comprising: The drive assembly includes three wheels, each driven by a separate in-wheel motor. Range extender; Waste heat recovery device, used to recover waste heat from the range extender; The thermal management circuit includes a battery heat exchange circuit, a cab heat exchange circuit, a valve group connecting the battery heat exchange circuit and the cab heat exchange circuit, and a circulating pump shared by the battery heat exchange circuit and the cab heat exchange circuit. The circulating pump, in conjunction with the valve group, adjusts the on / off state and opening degree to achieve flow distribution in each heat exchange circuit. The sensing unit is used to collect vehicle power parameters and thermal demand parameters; The controller is connected to the range extender, valve group, circulating pump and sensing unit, and configured to perform the steps of the three-wheel split hub motor range extender temperature control method described above.

[0014] The beneficial effects of this invention are as follows: by using the vehicle's power margin as a constraint variable for heating control, a direct relationship is established between heating decisions and the vehicle's real-time power capability. Through a multi-level, graded heating strategy, heating is systematically reduced when the margin narrows, fundamentally cutting off the negative feedback loop where heating power consumption lowers battery power margin, leading to even lower temperatures and smaller margins. This significantly reduces the probability of vehicle restrictions and breakdowns. The heat obtained from battery preheating under any heating strategy is no less than the heat corresponding to the battery's preheating guarantee power, ensuring that the battery temperature at least does not decrease further or slowly recovers, thereby guaranteeing the vehicle's basic driving capability and preventing disruption to continuous agricultural freight operations due to battery depletion or unexpected shutdowns. The energy utilization sequence of prioritizing waste heat and using electric heating as a backup, along with the range extender's heat demand-triggered start-stop and shutdown-based heat storage and delayed heat extraction, fully utilizes the heat originally released into the atmosphere, reducing heating power consumption and improving low-temperature driving range without changing the hardware. Attached Figure Description

[0015] In the attached diagram: Figure 1 This is a flowchart of a three-wheel split hub motor range extender temperature control method according to the present invention; Detailed Implementation

[0016] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0017] Example 1 Combination Figure 1 This embodiment provides a three-wheeled, separate hub motor range extender temperature control method, which is executed cyclically by a controller according to a control cycle. Each control cycle includes the following steps: S1. Collect vehicle thermal demand parameters and power parameters, and calculate vehicle power margin.

[0018] The thermal demand parameters include battery temperature, cab temperature, and cab heating signal, with the cab heating signal provided by the driver via a heating switch.

[0019] Power parameters include at least the battery state of charge, the maximum allowable discharge power of the battery, the range extender's power generation, the vehicle's driving power requirements, and the power of vehicle accessories. The maximum allowable discharge power of the battery is given by the battery management system based on the current battery temperature and state of charge. The range extender's power generation is zero when the range extender is not running. The vehicle's driving power requirements are obtained by analyzing the accelerator pedal opening and vehicle speed. The power of vehicle accessories refers to the total electrical power of the vehicle, excluding preheating and heating, such as lights and instruments.

[0020] The vehicle's power margin equals the sum of the range extender's generating power and the battery's maximum allowable discharge power, minus the sum of the vehicle's driving power requirements and the power of vehicle accessories.

[0021] In addition, the controller also reads the feedback quantity generated after the execution of the previous control cycle. The feedback quantity includes at least the measured battery temperature, the measured cab temperature, and the measured circulating medium temperature. It is used to characterize the actual execution effect of the control command in the previous cycle, so that the allocation of the current cycle is based on the actual temperature rise result, thereby forming a closed loop. The controller verifies the validity of each signal and sets a fault flag for signals that are out of bounds, have abnormal rate of change, or have excessive deviation from redundant measurement points.

[0022] S2. Based on the vehicle's power margin, determine the upper limit of available heating power and the battery preheating guarantee power, and determine the battery preheating demand and cab heating demand based on the heat demand parameters. When the vehicle's power margin is less than or equal to zero, the upper limit of available heating power is set to zero.

[0023] The upper limit of available heating power decreases as the vehicle's power margin decreases. For example, when the vehicle's power margin is not less than the first preset threshold, the upper limit of available heating power can be taken as the rated power of the electric heating element, that is, no restriction is imposed on electric heating. When the vehicle's power margin decreases, the upper limit of available heating power is adjusted proportionally to the decrease in the vehicle's power margin.

[0024] The battery preheating guarantee power is determined based on the battery temperature: the lower the battery temperature, the greater the heat required to raise it back to the discharge threshold temperature, and the higher the value of the battery preheating guarantee power, but it should not be lower than the preset minimum value.

[0025] The battery preheating requirement is determined by the deviation between the battery temperature and the preheating target temperature, and the cab heating requirement is determined by the deviation between the cab temperature and the heating target temperature. The two respectively represent the amount of heat required to heat the battery and the cab to their respective target temperatures.

[0026] S3. Execute the corresponding graded heating strategy according to the following judgment, wherein the first preset threshold is greater than the second preset threshold.

[0027] The waste heat generated by the range extender includes exhaust waste heat and coolant waste heat. During heating, heat sources are used in order of increasing cost per unit of heat: exhaust waste heat first, then coolant waste heat, and finally electric heating. The cost of exhaust waste heat is only the pumping power of the circulating pump, and this heat would be released into the atmosphere if not recovered, so it has the lowest cost. The cost of coolant waste heat includes pumping power, but also the cost of prolonged warm-up, increased fuel consumption, and emissions during the engine warm-up phase. Therefore, the cost is higher than that of exhaust waste heat when the coolant temperature is low, and it decreases significantly after warm-up. The cost of electric heating is the electrical power itself, and the electrothermal conversion ratio is no more than 1, making it the most expensive option.

[0028] Table 1. Order of Heat Source Utilization and Cost of Utilization Referring to Table 2, the heat demand is arranged from high to low according to its relevance to vehicle power availability. The battery preheating demand is the highest because the battery temperature directly determines the maximum allowable discharge power of the battery, which in turn determines whether the vehicle has driving capability and whether it will be restricted due to power limitation. This belongs to the power availability level. The cab heating demand belongs to the comfort level and can be reduced first.

[0029] Table 2 lists both the defrosting and defogging requirements for the windshield and the preheating requirements for the separate wheel hub motors, the specific implementation of which is explained in Example 3. Table 3 also lists the fourth heating strategy, the specific process of which is explained in Example 2.

[0030] Table 2. Priority of Heat Demand and Reasons for Ranking Refer to Table 3 to implement the corresponding heating strategy according to the range of vehicle power margin.

[0031] Table 3. Tiered Heating Strategies and Reduction Methods As shown in Table 3, the output power of electric heating is reduced first in the tiered heating scheme because electric heating is the only heat source with an electrothermal conversion ratio of no more than 1. Reducing it minimizes the cost-effectiveness loss of total heat supply and maximizes the recovery of vehicle power margin. The demand for cab heating is then reduced because heating is a comfort requirement. The battery preheating demand is provided with heat no less than the guaranteed battery preheating power under the first, second, and third heating strategies. This safety net is key to cutting off the negative feedback loop of "the more heating, the more breakdowns." When the range extender is not in operation, the residual heat is zero. Under the first heating strategy, the electric heating supplements all heat demand according to the upper limit of available heating power.

[0032] Taking a typical operating condition of daily freight transport in northern winter as an example: the ambient temperature is -8℃, the vehicle is parked outdoors overnight, the battery temperature is -7℃, and the state of charge is 55%. After the driver powers on the battery, he requests to depart and turns on the heating. During the first control cycle, the range extender has not yet started, the range extender's power generation is zero, the vehicle's power margin is low, and the controller executes the third heating strategy, using only electric heating to ensure power supply based on battery preheating.

[0033] Subsequently, due to the need for battery preheating, the heat demand triggered the range extender to start, increasing its power output from zero to 1500W. The vehicle's power reserve then rose above the first preset threshold, and the controller automatically switched to the first heating strategy: exhaust waste heat was prioritized for battery preheating, and the remaining waste heat was used for cab heating; electric heating was not activated or only used for low-power peak regulation. If the vehicle then climbs a hill fully loaded, causing a sudden increase in driving power demand, and the vehicle's power reserve falls back to between the first and second preset thresholds, the controller reduces the electric heating output power according to the second heating strategy. If it continues to fall below the second preset threshold, the third heating strategy further reduces the heat and power required for cab heating. Throughout the process, the heat gained from battery preheating never falls below the guaranteed preheating power, and the battery temperature continues to rise. The driver only experiences a weakening of the heating air, not a vehicle slowdown or shutdown.

[0034] S4. Based on the heating strategy determined in S3, control the start-stop and output power of the range extender according to the battery state of charge, heat demand parameters and vehicle power margin, and control the opening degree of the thermal circuit valve group and the speed of the circulation pump.

[0035] Specifically, the control commands output by the controller include: start / stop commands and power generation settings of the range extender, the opening degree of each passage of the valve group between the battery heat exchange circuit and the cab heat exchange circuit, the speed or duty cycle of the circulating pump shared by the two circuits, and the speed of the heating fan and the duty cycle of the electric heating power.

[0036] After this control cycle ends, it returns to S1 and begins the next control cycle. The three operating conditions are: pure electric mode, where the range extender does not start, and the heat source is electric heating and residual heat from the circuit; range extender mode, where the range extender operates according to an energy strategy, with waste heat as the primary heat source; and forced heating mode, where heat demand dominates the start-stop decision, and the range extender may start due to heat demand. Switching between these three modes is based on criteria, and the switching itself does not interrupt the cyclic execution of the aforementioned control cycle.

[0037] It should be noted that this embodiment focuses on protecting the core idea of ​​a graded heating strategy constrained by vehicle power margin. The specific values ​​of the above parameters and thresholds, as well as the specific forms of heat source and heat demand, are all illustrative examples and do not constitute a limitation on actual production. In actual applications, they can be flexibly adjusted according to the vehicle power level, battery system, heat source form and target market.

[0038] Based on the above design, this embodiment establishes a direct relationship between heating decisions and the vehicle's real-time power capability by using the vehicle's power margin as a core control variable. It also employs a three-tiered heating strategy to orderly reduce power consumption when the margin narrows while ensuring a minimum supply for battery preheating. This mechanism effectively cuts off the negative feedback loop that leads to lower battery power margin due to heating power consumption, resulting in even lower temperatures and smaller margins. This significantly reduces the probability of vehicle restrictions and breakdowns.

[0039] Example 2 This embodiment is an optimized version of embodiment 1. Its core is to further improve the reliability and energy utilization rate under cold outdoor conditions by refining the battery preheating requirements, implementing a limp-out strategy under extreme operating conditions, and coordinating start-stop and waste heat recovery on the range extender side.

[0040] First, the determination of battery preheating requirements and target temperature in Example 1 are dynamically adjusted. The battery preheating requirements are determined in segments according to battery temperature: When the battery temperature is below the first battery temperature threshold, high-current charging and discharging of the battery is prohibited, and preheating is only allowed using the residual heat of the range extender or a small current. When the battery temperature is between the first battery temperature threshold and the second battery temperature threshold, preheating is allowed while driving in a power-limited mode. When the battery temperature reaches the exit preheating temperature, preheating is stopped.

[0041] The preheating target temperature increases with the increase of the battery's state of charge and decreases with the increase of the vehicle's driving power demand, and is not lower than the battery's discharge threshold temperature. For example, when the state of charge is high and the vehicle's driving power demand is low, the preheating target temperature is set at 18℃-20℃ to fully restore the battery's discharge capacity. When the state of charge is low or the vehicle's driving power demand is high, the preheating target temperature is only set to near the discharge threshold temperature, such as 5℃-8℃, which is enough to stop the battery from discharging normally and transfer the limited heat to the cab heating. In this way, it avoids both the limited discharge capacity caused by insufficient preheating and the energy waste caused by excessive preheating.

[0042] In addition, the temperature of the circulating medium entering the battery water jacket is controlled by the mixing water bypass to be no higher than the upper limit temperature of the water entering the battery side, such as 45°C, so as to avoid local overheating of the battery and excessive temperature difference. When the vehicle is in the plug-in state, the electrical energy required for battery preheating is provided by the external power source through the on-board charger, without consuming battery power.

[0043] Step S3 also includes a fourth heating strategy: When the vehicle's power margin is less than the third preset threshold and the battery temperature is still below the discharge threshold temperature, the fourth heating strategy is executed: the vehicle's driving power is limited to the preset limp power limit, and the range extender is forcibly started to maintain the vehicle's mobility in limp mode. When the vehicle's power margin recovers to above the second preset threshold and the battery temperature is above the discharge threshold temperature for a preset duration, the limp mode is exited. The entry and exit thresholds of the limp mode are set with hysteresis to avoid frequent strategy switching under critical conditions. The third preset threshold is less than the second preset threshold. For example, the first preset threshold is 800W, the second preset threshold is 200W, and the third preset threshold is 0W. The preset limp power limit is calibrated to 30%-40% of the rated driving power according to the vehicle's power level.

[0044] Upon entering the fourth heating strategy, within this control cycle, the vehicle's drive power is first limited to the preset limp power limit at a rate not exceeding 10% / s of the rated power, in conjunction with instrument prompts to avoid sudden stalling and resulting handling risks. Simultaneously, the range extender is forcibly activated to operate at its optimal specific fuel consumption power point rather than following the load, thereby increasing the range extender's power generation. Subsequently, the vehicle's power margin is recalculated using the limited drive power and the increased power generation, and the heating strategy is determined based on the recalculation result. Due to the decrease in the vehicle's drive power demand and the increase in the range extender's power generation, the combined effect of these two factors restores the vehicle's power margin. This recalculation constitutes the inner closed loop of the method. As the battery temperature rises, the maximum allowable discharge power of the battery increases, and the vehicle's power margin automatically improves in subsequent control cycles. The controller gradually restores normal drive capability at the same rate, without requiring additional mode exit criteria.

[0045] Taking continuous operation in extreme cold as an example: When the vehicle operates continuously in an environment of -25℃, the state of charge drops to 18% and the battery temperature is -12℃. During this control cycle, the vehicle's power margin is less than the third preset threshold and the battery temperature is still below the discharge threshold temperature. The controller executes the fourth heating strategy. The vehicle speed is limited but still maintains mobility, allowing it to leave the work area or complete the current work section, thus avoiding downtime in the field.

[0046] In step S4, the range extender is triggered to start and stop based on the battery state of charge (SBC), battery preheating demand, or cab heating demand: it is triggered by battery charge when the SBC is below the start-up threshold; it is triggered by heat demand when there is a battery preheating demand but no available residual heat, or when the cab heating demand is continuous but the circulating medium temperature is insufficient. This design allows heat demand to participate in the source-side decision-making, avoiding the waste of the range extender not starting when there is heat demand but the SBC is still high, and having to rely entirely on electric heating.

[0047] The range extender is designed with a minimum continuous operating time and a minimum start-stop interval to suppress frequent start-stop and cold start emissions degradation.

[0048] When the estimated downtime exceeds the preset duration, the circulating medium is heated to the upper limit of the heat storage temperature before the range extender stops, so that the circuit medium and its insulation layer form a tankless heat storage body. After the shutdown, the circulating pump runs for a delay to recover the residual heat in the waste heat recovery device and the circulating medium until the temperature of the circulating medium drops to the lower limit or the heat demand disappears. For example, the upper limit of the heat storage temperature is 90°C, and the conventional target temperature is 65°C. After the shutdown, the circulating pump runs intermittently at about 1 / 3 of its capacity, such as running for 30 seconds and stopping for 60 seconds, for about 6 minutes or until the temperature of the circulating medium drops to 40°C. Intermittent rather than continuous pumping is used after the shutdown to suppress pump power consumption and avoid local overheating and temperature stratification. It should be noted that the above-mentioned heat storage before shutdown may not be executed in short-term shutdown scenarios, such as waiting at a red light or temporary loading and unloading. Whether to execute it is determined by the controller based on the estimated downtime.

[0049] The exhaust heat exchange branch and the coolant heat exchange branch are also switched between series and parallel operation via valve assemblies: During the cold start phase, the two are controlled to be connected in series and run at a small flow rate, so that the circulating medium is heated rapidly by passing through the exhaust side and the coolant side in sequence. During this phase, a large amount of heat is deliberately not taken from the coolant to avoid prolonging engine warm-up, increasing fuel consumption and emissions; When the circulating medium temperature reaches the first medium temperature threshold or the coolant temperature reaches the temperature that can be connected, the circuit is switched to parallel operation and runs at a large flow rate to improve the total heat recovery rate and reduce flow resistance; When the circulating medium temperature is higher than the upper limit temperature of heat storage or the engine is under high load, the exhaust branch is closed or bypassed to prevent the exhaust back pressure from rising and affecting the engine power output and to protect the heat exchanger. This series-parallel switching is achieved by reorganizing the existing valve assembly passages without increasing the number of valves.

[0050] This embodiment avoids energy waste caused by excessive preheating by refining the battery preheating requirements and combining thermoelectric synergy on the range extender side. This ensures that the residual heat after the range extender stops is not wasted, and under extreme conditions, limited drive power is used to keep the machine running, thus preserving operational continuity and the driver's leeway.

[0051] Example 3 This embodiment is an optimized version of embodiment 1. Its core is to expand the coverage of thermal demand and add degradation processing under abnormal operating conditions, thereby further improving driving safety, low-temperature mechanical efficiency, energy utilization and system availability.

[0052] In step S2, the thermal demand parameters also include the windshield temperature and the humidity inside the cab. The thermal demand also includes the windshield defrosting and defogging demand, which has a default priority between the battery preheating demand and the cab heating demand. The controller calculates the dew point temperature based on the windshield temperature and the humidity inside the cab, and uses the difference between the windshield temperature and the dew point temperature as the dew point margin to determine whether there is a risk of fogging and frosting.

[0053] If a risk exists, the priority of the windshield defrosting and defogging requirement will be temporarily updated to the highest priority within the current control cycle. The updated priority will be input into step S3 to participate in the heating strategy allocation, that is, temporarily preempting the valve group opening and heating fan air volume, and limiting the power of non-safe loads such as seat heating if necessary. This update is a temporary overlay. After the risk is eliminated and confirmed after a delay, it will automatically revert to the default priority. For example, when the dew point margin is lower than 2°C, an early warning will be issued and the defrosting air volume will be increased. When the dew point margin is lower than 0°C or it is determined that the windshield has fogged or frosted, preemption will be triggered. Preemption will continue until the dew point margin recovers to above 5°C and will be released after a delay of 60 seconds.

[0054] In step S2, the heat demand also includes the preheating demand of at least one of the separate hub motor and the reduction mechanism. When the battery preheating demand has been met or the circulating medium has sufficient heat, and the temperature of the separate hub motor or the reduction mechanism is lower than the preheating threshold, step S3 distributes heat to meet the preheating demand while outputting a torque limiting command to limit the peak torque of the separate hub motor during the preheating process.

[0055] For example, the preheating threshold is set at 0℃. During the preheating period, the peak torque of the split hub motor is limited to 60%-70% of the rated peak torque, and the drive torque distribution ratio between each wheel is adjusted to shift towards the side with higher temperature and lower resistance. After the temperature reaches the preheating threshold, the normal torque and distribution are restored. At low temperatures, the viscosity of the lubricating medium in the deceleration mechanism increases, which will significantly increase the oil churning loss and mechanical resistance. This preheating not only reduces the vehicle's power consumption and improves the effective driving range, but also avoids the impact of high torque at low temperatures on gears and bearings.

[0056] During the preheating of the separate hub motor and reduction mechanism, the peak torque of the separate hub motor needs to be limited. The torque limitation adopts a smooth and gradual method to avoid sudden torque changes. The output torque deviation of the rear left and right separate hub motors is controlled to not exceed the preset safety threshold. The deep torque limiting strategy is implemented first when the vehicle is stationary or at low speed. When the vehicle is climbing or driving at high speed, the torque limiting intensity is reduced to ensure driving stability and prevent the risk of steering deviation and rollover.

[0057] The power parameters also include vehicle feedback power. In step S3, when allocating the heating strategy, if the vehicle feedback power exceeds the battery's acceptable power, the excess portion is converted into heat and incorporated into the available heat source for heating. Specifically, the battery management system provides the battery's acceptable power in real time. When the vehicle is in braking or coasting feedback mode and the vehicle feedback power exceeds the acceptable power, the excess portion is directed to the electric heating element to be converted into heat, stored in the circulating medium, or directly sent to the cab, instead of being charged into the battery. This measure retains the electric braking capability when the battery's low-temperature charging is limited, reduces the risk of thermal degradation and lock-up of mechanical braking on icy roads, and at the same time obtains free heat and avoids the risk of lithium plating during high-rate recharge at low temperatures.

[0058] While collecting parameters in step S1, abnormal operating condition detection is performed: when at least one of the following abnormalities is detected—circulation pump failure, range extender start failure, battery overheating warning, or excessive CO levels in the driver's cab—the current control cycle skips the graded heating strategy of S3, enters the corresponding downgraded heating mode, and issues an audible and visual warning to the driver. See Table 4.

[0059] Table 4 Abnormal Operating Conditions and Degraded Heating Modes Among them, the CO exceeding the limit in the driver's cab corresponds to the inherent safety risk of the exhaust waste heat recovery scheme. Therefore, the highest level of mandatory treatment is adopted. All downgraded heating modes adopt the minimum guarantee and gradual recovery exit mechanism: after the fault sign is cleared, the normal graded heating strategy is gradually restored according to the preset delay and hysteresis to avoid repeated switching caused by fault vibration.

[0060] In addition, hysteresis, delayed confirmation and gradual transition are set between each heating strategy and between each heat demand level. For example, the exit from preheating adopts a hysteresis of 15°C to enter and 12°C to exit; the target values ​​of valve groups, circulating pumps and fans are transitioned with a 2-5 second ramp to avoid water hammer, abnormal noise and frequent actuator operation.

[0061] This embodiment improves visibility safety by temporarily prioritizing the defrosting and defogging of the windshield, reduces low-temperature mechanical resistance by preheating and limiting the torque of the separate hub motor and its reduction mechanism, avoids the waste of braking energy by converting feedback power into heat, and ensures that no single point of failure will lead to the overall paralysis of the thermal management system by degrading mechanisms covering various anomalies such as the pump, range extender, battery, and exhaust safety, thus meeting the actual needs of continuous operation of agricultural freight transport.

[0062] Example 4 This embodiment provides a three-wheeled split-type hub motor range extender temperature control system for executing a three-wheeled split-type hub motor range extender temperature control method as described in any of Embodiments 1 to 3.

[0063] The system includes a controller and an extended range extender electrically connected to it, a waste heat recovery device, a thermal management circuit, a sensing unit, and a drive assembly.

[0064] The drive assembly includes three wheels: one front wheel and two rear wheels located on either side of the rear axle. Each of the three wheels is driven by a separate, independent hub motor, forming a three-wheel drive configuration. The vehicle also includes a chassis, a rear axle, and shock absorbers. The rear axle and shock absorbers are arranged at the rear of the chassis according to the conventional structure of agricultural freight tricycles. The separate hub motors include a motor body and a reduction mechanism. The motor body can be a 72V / 2000W (or 1800W) brushless DC motor. Its output is reduced and increased in torque by an internal gear ring reduction mechanism before driving the wheel rims. The separate hub motors are rigidly fixed to the rear axle by an L-shaped iron plate. The L-shaped iron plate has a heat exchange jacket inside or on its surface, making it both a fixing component and a heat conduction component, providing a heat exchange path for the preheating of the reduction mechanism. This reuse design does not increase the number of parts.

[0065] The range extender includes an engine and a generator. The engine drives the generator to generate electricity, which is then supplied to the drive motor and / or battery via a power distribution unit.

[0066] The waste heat recovery device is connected to the engine and is used to recover the waste heat of the range extender. It includes an exhaust heat exchanger located on the engine exhaust passage and a coolant heat exchanger coupled to the engine coolant circuit. The exhaust heat exchanger has a double-layer structure with an inlet and outlet of circulating medium and forms a medium interlayer to absorb exhaust heat. The coolant heat exchanger is coupled to the engine coolant circuit, and the two can be switched between series and parallel connection through a valve group as described in Example 2.

[0067] The thermal management circuit includes a battery heat exchange circuit, a cab heat exchange circuit, a valve assembly connecting the battery heat exchange circuit and the cab heat exchange circuit, and a circulating pump shared by the battery heat exchange circuit and the cab heat exchange circuit. The valve assembly is configured to distribute the flow to the battery heat exchange circuit and the cab heat exchange circuit, that is, to adjust the flow ratio of the two circuits by combining the opening of each passage, thereby achieving differentiated supply to the two heat sinks under single pump conditions. The battery heat exchange circuit includes a battery water jacket and a mixing water bypass. The cab heat exchange circuit includes a heater core and a fan, and is also provided with a defrost duct connected to the windshield. The electric heating element is located in the circuit as a high-cost backup heat source, and also serves as an electrical load for feedback power conversion to heat. The circulating pump can be a 12V DC circulating pump, and the fan can be a 12V electric fan. The pipes outside the circuit are covered with a thermal insulation layer.

[0068] The sensing unit is used to collect vehicle power parameters and thermal demand parameters, including a battery temperature and voltage / current acquisition module, an ambient temperature sensor, a cab temperature sensor, a windshield temperature sensor, a cab humidity sensor, a coolant temperature sensor, a circulating medium temperature sensor, a loop flow and pressure sensor, and a cab CO concentration sensor.

[0069] The controller is connected to the range extender, valve group, circulating pump and sensing unit respectively, and is configured to execute the above-mentioned three-wheel separate hub motor range extender temperature control method. As the core hub, it is responsible for receiving signals from each sensor, calculating the vehicle power margin, determining the upper limit of available heating power and the battery preheating guarantee power, executing the graded heating strategy and outputting control commands such as range extender start / stop and power generation, valve group opening degree, circulating pump speed, etc. At the same time, it stores historical processing data and performs data matching when needed.

[0070] The following example, using a single control cycle, illustrates the coordinated actions of the various components of this system. The sensing unit collects data on battery temperature, cab temperature, cab heating signal, windshield temperature, cab humidity, maximum allowable battery discharge power, range extender power generation, vehicle drive demand power, vehicle accessory power, and vehicle feedback power, and sends this data to the controller. The controller then calculates the vehicle's power margin, determines the upper limit of available heating power, the battery preheating guarantee power, and various heat demands, and executes the corresponding tiered heating strategy. Subsequently, the controller outputs start / stop and power generation commands to the range extender, opening commands for each valve channel to the valve group, speed or duty cycle commands to the shared circulation pump, and corresponding commands to the heating fan and electric heating elements. If necessary, it also outputs torque limit commands to the motor controller. After this control cycle ends, the sensing unit re-collects data, and the system enters the next control cycle.

[0071] Specifically, when the first heating strategy is executed in this cycle, the controller adjusts the valve group to increase the flow ratio between the exhaust heat exchange branch and the battery heat exchange circuit, so that the exhaust waste heat is given priority to the battery preheating demand, and the waste heat surplus path is switched to the cab heat exchange circuit; when the second heating strategy is executed, the controller reduces the power duty cycle of the electric heating element, while maintaining the opening of the battery heat exchange circuit; when the third heating strategy is executed, the controller reduces the valve group opening of the cab heat exchange circuit and reduces the fan speed, while maintaining the supply to the battery heat exchange circuit; when the fourth heating strategy is executed, the controller outputs a torque limiting command to the motor controller to limit the vehicle's driving power, and outputs a forced start and optimal specific fuel consumption power point operation command to the range extender.

[0072] This system, through the linkage of controller, range extender, waste heat recovery device, thermal management loop and sensing unit, enables the two heat demands of battery preheating and cab heating to be supplied in an orderly manner according to level under the constraints of shared circulation pump and shared loop. It provides stable and reliable equipment support for the differentiated execution of the graded heating strategy and realizes the organic unity of hardware simplification and refined thermal management.

[0073] Parameter values The following is a set of exemplary values. Actual calibration can be adjusted according to the cell system, vehicle power level and target market. This invention does not limit this.

[0074] Table 5 Example values ​​for parameters Hysteresis and delayed confirmation should be set for each of the above thresholds to suppress frequent actuator movements.

[0075] The above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for temperature control of a three-wheeled, separate hub motor for range extension, characterized in that, The controller executes the commands cyclically according to a control cycle, and each control cycle includes the following steps: S1. Collect vehicle thermal demand parameters and power parameters, and calculate vehicle power margin; The heat demand parameters include battery temperature, cab temperature, and cab heating signal. The power parameters include at least the battery state of charge, the maximum allowable battery discharge power, the range extender power generation, the vehicle drive demand power, and the power of vehicle accessories. The vehicle power margin equals the sum of the range extender's generating power and the battery's maximum allowable discharge power, minus the sum of the vehicle's driving power requirement and the vehicle's accessory power. S2. Based on the vehicle's power margin, determine the upper limit of available heating power and the guaranteed power for battery preheating, and determine the battery preheating requirements and cab heating requirements based on the heat demand parameters. S3. Implement the corresponding tiered heating strategy according to the following judgments: When the vehicle's power margin is greater than or equal to the first preset threshold, the first heating strategy is implemented: the waste heat generated by the range extender is used to supply the battery preheating needs first, and then the waste heat margin is used to supply the cab heating needs. The insufficient part is supplemented by electric heating, and the electric heating power does not exceed the upper limit of the available heating power. When the second preset threshold ≤ vehicle power margin < the first preset threshold, the second heating strategy is executed: reduce the output power of electric heating, retain the heat supply corresponding to the battery preheating demand, and the heat obtained by the battery preheating demand is not less than the heat corresponding to the battery preheating guarantee power. When the vehicle's power margin is less than the second preset threshold, the third heating strategy will be implemented: reduce the heat and power corresponding to the heating demand of the cab, prioritize the heat supply for the battery preheating demand, and ensure that the heat obtained by the battery preheating demand is not less than the heat corresponding to the battery preheating guarantee power. Where the first preset threshold is greater than the second preset threshold; S4. Based on the heating strategy determined in S3, control the start-stop and output power of the range extender according to the battery state of charge, heat demand parameters and vehicle power margin, and control the opening degree of the thermal circuit valve group and the speed of the circulating pump. After completing this cycle, return to S1 to enter the next control cycle for repeated execution.

2. The method for range extension and temperature control of a three-wheeled, separate hub motor according to claim 1, characterized in that, In step S3, the waste heat generated by the range extender includes exhaust waste heat and coolant waste heat. When supplying heat, the heat sources are used in order of increasing cost per unit of heat: exhaust waste heat, coolant waste heat and electric heating.

3. The method for range extension and temperature control of a three-wheeled, separate hub motor according to claim 1, characterized in that, In step S2, the battery preheating requirement is determined in segments according to battery temperature. The preheating target temperature increases with the increase of battery state of charge and decreases with the increase of vehicle driving power demand. The preheating target temperature is not lower than the battery discharge threshold temperature.

4. The method for range extension and temperature control of a three-wheeled, separate hub motor according to claim 1, characterized in that, Step S3 also includes a fourth heating strategy: when the vehicle power margin is less than the third preset threshold and the battery temperature is still below the discharge threshold temperature, the vehicle drive power is limited to the preset limp power limit and the range extender is forcibly started so that the vehicle maintains mobility in limp mode, and the third preset threshold is less than the second preset threshold.

5. The method for range extension temperature control of a three-wheeled, separate hub motor according to claim 1, characterized in that, In step S4, the range extender is triggered to start and stop by the battery state of charge, battery preheating requirements, or cab heating requirements. When the estimated downtime exceeds the preset time, the circulating medium is heated to the upper limit of heat storage temperature before the range extender stops, and the circulating pump is run for a delay after the stop to recover residual heat.

6. The method for range extension temperature control of a three-wheeled, separate hub motor according to claim 1, characterized in that, In step S2, the thermal demand parameters also include the windshield temperature and the humidity inside the cab. The thermal demand also includes the windshield defrosting and defogging demand, and its default priority is between the battery preheating demand and the cab heating demand. Based on the windshield temperature and cabin humidity, determine whether there is a risk of fogging or frost. If so, temporarily update the priority of windshield defrosting and defogging needs to the highest priority within the current control cycle, and input the updated priority into step S3 to participate in the heating strategy allocation.

7. The method for range extension temperature control of a three-wheeled, separate hub motor according to claim 1, characterized in that, In step S2, the heat demand also includes the preheating demand of at least one of the separate hub motor and the reduction mechanism. In step S3, while distributing heat to meet the preheating demand, a torque limiting command is output to limit the peak torque of the separate hub motor during the preheating process.

8. The method for range extension temperature control of a three-wheeled, separate hub motor according to claim 1, characterized in that, The power parameters also include vehicle feedback power. In step S3, when allocating the heating strategy, if the feedback power exceeds the battery's acceptable power, the excess portion will be converted into heat and incorporated into the available heat source for heating.

9. The method for range extension temperature control of a three-wheeled, separate hub motor according to claim 1, characterized in that, While collecting parameters in step S1, abnormal operating condition detection is performed. When at least one of the following abnormalities is detected: circulation pump failure, range extender start failure, battery heat warning, or CO exceeding the limit in the cab, the current control cycle skips the graded heating strategy of S3 and enters the corresponding degraded heating mode. When CO exceeding the limit in the cab is detected, the degraded heating mode includes at least stopping the air supply to the cab and shutting down the range extender.

10. A three-wheeled, separate hub motor range extender temperature control system, characterized in that, A method for implementing the range-extending temperature control of a three-wheeled, separate hub motor according to any one of claims 1-9 includes: The drive assembly includes three wheels, each driven by a separate hub motor, and each hub motor is equipped with a reduction gear. Range extender; Waste heat recovery device, used to recover waste heat from the range extender; The thermal management circuit includes a battery heat exchange circuit, a cab heat exchange circuit, a valve group connecting the battery heat exchange circuit and the cab heat exchange circuit, and a circulating pump shared by the battery heat exchange circuit and the cab heat exchange circuit. The circulating pump, in conjunction with the on / off and opening degree adjustment of the valve group, realizes the flow distribution of each heat exchange circuit. The sensing unit is used to collect vehicle power parameters and thermal demand parameters; The controller is connected to the range extender, valve assembly, circulating pump, and sensing unit and configured to perform the steps of any one of claims 1-9.

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