Dual electric drive axle temperature control system, method, and vehicle

Abstract

The application relates to a dual electric drive axle temperature control system, method and vehicle, which comprises a temperature acquisition unit, a thermal management loop, a heat pump unit and a main control unit. The temperature acquisition unit is arranged in the dual electric drive axle. The thermal management loop comprises a cooling liquid storage unit, a water pump unit, a three-way valve unit and a heat exchange unit. The heat exchange unit is at least partially arranged on the dual electric drive axle. The water pump unit is arranged between the cooling liquid storage unit and the three-way valve unit. The heat pump unit is in thermal communication with the heat exchange unit, and is used for transferring heat of the dual electric drive axle to an air conditioning system or a power battery under a preset condition. The main control unit is electrically connected with the above units, and is used for controlling the flow of the water pump unit and the opening of the three-way valve unit according to oil temperature, adjusting the cooling liquid flow into the heat exchange unit, and / or controlling the output torque distribution ratio of the dual electric drive axle, and / or controlling the working state of the heat pump unit, so that the oil temperature of the dual electric drive axle is maintained in a preset temperature range.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of new energy commercial vehicle electric drive axle thermal management system, and particularly relates to a double electric drive axle temperature control system and method and a vehicle. BACKGROUND

[0002] At present, pure electric heavy trucks are in the transition stage from traditional fuel vehicles to pure electric special platform upgrade. In terms of driving form, some manufacturers adopt double motor drive scheme based on economic consideration, while the more advanced technical route is to adopt double electric drive axle scheme of distributed drive. The double electric drive axle realizes vehicle operation through independent control of front and rear axles, and provides better energy consumption performance while ensuring power performance.

[0003] The electric drive axle is a power assembly component integrating the motor, the reducer and the differential, and needs to be equipped with lubricating oil inside to realize the lubrication and cooling of the gear set and the bearing. The transmission efficiency of the electric drive axle is closely related to the temperature of the lubricating oil inside, and generally, the optimal working temperature range of the electric drive axle is 80-90 DEG C. However, the prior art at least has the following defects:

[0004] 1) The cooling system of the existing electric drive axle adopts a straight-through water cooling structure, and the cooling water continuously takes away heat from the oil heat exchange plate, so that even under the condition of heavy load and environmental temperature of 40 DEG C, the oil temperature of the electric drive axle can only reach about 70 DEG C;

[0005] 2) Due to the characteristics of high integration, the electric drive axle has a larger passive heat dissipation capacity than the traditional axle, which further aggravates the problem of low oil temperature;

[0006] 3) The continuous low oil temperature below the optimal working range leads to high viscosity of the lubricating oil, increases mechanical loss, and causes the increase of vehicle energy consumption and the decrease of driving efficiency.

[0007] Based on the above defects, how to raise the oil temperature of the electric drive axle and maintain it in the optimal working range to improve the transmission efficiency of the electric drive axle and reduce the vehicle energy consumption has become a technical problem to be solved at present. SUMMARY

[0008] The present application discloses a double electric drive axle temperature control system and method and a vehicle, which aims to solve the technical problems existing in the prior art.

[0009] The present application adopts the following technical scheme:

[0010] In a first aspect, the present application provides a double electric drive axle temperature control system, which comprises:

[0011] a temperature acquisition unit, arranged at least in the double electric drive axle, for detecting the oil temperature of the double electric drive axle respectively;

[0012] a heat management circuit comprising a coolant storage unit, a water pump unit, a three-way valve unit and a heat exchange unit, the heat exchange unit is at least partially arranged on the dual electric drive axle, the water pump unit is arranged between the coolant storage unit and the three-way valve unit, an inlet of the three-way valve unit is in communication with an outlet of the water pump unit, a first outlet of the three-way valve unit is in communication with the heat exchange unit, and a second outlet of the three-way valve unit is in communication with the coolant storage unit circuit;

[0013] a heat pump unit in thermal communication with the heat exchange unit, for transferring heat of the dual electric drive axle to an in-vehicle air conditioning system or a power battery under a preset condition;

[0014] a main control unit electrically connected with the temperature acquisition unit, the water pump unit, the three-way valve unit and the heat pump unit, respectively, for controlling the flow of the water pump unit and the opening of the three-way valve unit according to the oil temperature to adjust the flow of the coolant entering the heat exchange unit, and / or controlling the output torque distribution ratio of the dual electric drive axle, and / or controlling the working state of the heat pump unit, so that the oil temperature of the dual electric drive axle is maintained within a preset temperature range.

[0015] In some embodiments, the dual electric drive axle comprises a motor, a gearbox and a motor controller;

[0016] The heat exchange unit comprises a first heat exchange unit, a second heat exchange unit and a third heat exchange unit in sequence, wherein the first heat exchange unit is arranged on the motor controller, the second heat exchange unit is arranged on the motor, and the third heat exchange unit is arranged on the gearbox; the coolant can flow through the first heat exchange unit, the second heat exchange unit and the third heat exchange unit in sequence.

[0017] In some embodiments, the heat management circuit further comprises a flow sensor electrically connected with the main control unit for detecting the flow of the coolant.

[0018] In some embodiments, the heat pump unit comprises a refrigerant circuit and a plate heat exchanger;

[0019] One side of the plate heat exchanger is in thermal communication with the heat exchange unit, and the other side is in communication with the refrigerant circuit;

[0020] The refrigerant circuit comprises a compressor, a first condenser, a second condenser, a throttling element and an evaporator, the first condenser is in thermal communication with the in-vehicle air conditioning system, the second condenser is in thermal communication with the power battery, and the evaporator exchanges heat with the heat exchange unit through the plate heat exchanger.

[0021] In a first aspect, the embodiments of the present application provide a dual-motor-bridge temperature control method using the system according to any one of the above, characterized in that the method comprises:

[0022] acquiring a temperature signal of the temperature acquisition unit in real time;

[0023] judging whether the oil temperature of the dual-motor-bridge is within a preset temperature range based on the temperature signal;

[0024] determining a target flow rate of the water pump unit, a target opening degree of the three-way valve unit, and a target output torque distribution ratio of the dual-motor-bridge according to the judgment result;

[0025] monitoring the temperature regulation control execution effect of the dual-motor-bridge, and dynamically adjusting the target flow rate, and / or the target opening degree, and / or the target output torque ratio according to the change trend of the temperature signal until the oil temperature returns to the preset temperature range.

[0026] In some embodiments, the method further comprises:

[0027] acquiring a working state signal of an in-vehicle air conditioning system and a power battery, and the temperature signal of the dual-motor-bridge;

[0028] starting a heat pump unit when a preset heat pump starting condition is met, and controlling the heat pump unit to transfer heat of the dual-motor-bridge to the in-vehicle air conditioning system or the power battery;

[0029] determining a priority of a heat transfer object based on the working state signal and the temperature signal, and performing corresponding heat transfer control.

[0030] In some embodiments, in the step of determining the target flow rate of the water pump unit, the target opening degree of the three-way valve unit, and the target output torque distribution ratio of the dual-motor-bridge according to the judgment result, the method comprises:

[0031] when the oil temperature is lower than a first preset temperature, controlling the water pump unit to reduce the target flow rate, and / or controlling the three-way valve unit to increase the target opening degree of the first outlet;

[0032] when the oil temperature reaches the first preset temperature, controlling the three-way valve unit to reduce the target opening degree of the first outlet until the first outlet is closed, and keeping the second outlet open;

[0033] when the oil temperature reaches a second preset temperature, controlling the three-way valve unit to increase the target opening degree of the first outlet, and / or controlling the water pump unit to increase the target flow rate;

[0034] the first preset temperature is less than the second preset temperature.

[0035] In some embodiments, in the step of determining the target flow rate of the water pump unit, the target opening degree of the three-way valve unit, and the target output torque distribution ratio of the double electric drive axle according to the determination result, the step comprises:

[0036] Synchronously adjusting the target flow rate and the target opening degree based on a preset flow rate-opening degree-oil temperature correlation model.

[0037] In some embodiments, in the step of determining the target flow rate of the water pump unit, the target opening degree of the three-way valve unit, and the target output torque distribution ratio of the double electric drive axle according to the determination result, the step comprises:

[0038] When it is detected that the oil temperature difference of the double electric drive axle exceeds a preset threshold value, the target output torque distribution ratio is adjusted so that the electric drive axle with higher oil temperature reduces the output torque and the electric drive axle with lower oil temperature increases the output torque until the oil temperatures of the two electric drive axles tend to be balanced.

[0039] In a third aspect, the embodiments of the present application provide a vehicle comprising the double electric drive axle temperature control system according to any one of the above.

[0040] The above-mentioned embodiments of the present application have the following advantages or beneficial effects:

[0041] The embodiments of the present application mainly provide a double electric drive axle temperature control system, method and vehicle. Compared with the prior art, the embodiments of the present application establish a closed-loop control system for the temperature of the double electric drive axle, thereby realizing accurate adjustment of the oil temperature in the double electric drive axle. Specifically, in the low-temperature stage, the heat exchange efficiency of the coolant is improved by reducing the flow rate of the water pump and increasing the opening degree of the three-way valve. After the oil temperature reaches the temperature of the coolant, the heat exchange channel of the three-way valve is closed for bypassing, so that the oil temperature can quickly rise to the optimal working temperature. After the oil temperature reaches the safety threshold temperature, the flow rate of the water pump and the opening degree of the three-way valve are dynamically adjusted based on a preset flow rate-opening degree-oil temperature correlation model, thereby ensuring that the double electric drive axle always works in the optimal temperature range.

[0042] In addition, the embodiments of the present application also introduce a temperature balancing control strategy between the double electric drive axles. By monitoring the temperature difference between the front electric drive axle and the rear electric drive axle in real time, the output torque distribution ratio of the two electric drive axles is dynamically adjusted, thereby avoiding the risk of excessively high temperature of a single electric drive axle and improving the heat dissipation efficiency and energy utilization efficiency of the vehicle power system.

[0043] Further, the embodiments of the present application also integrate a heat pump system, thereby realizing collaborative management of the heat of the double electric drive axle, the air conditioning system in the vehicle and the power battery. When the preset heat pump starting condition is met, the system can reasonably transfer the heat of the double electric drive axle to the object with heating demand, thereby improving the comprehensive utilization efficiency of the heat energy of the vehicle and improving the deep integration and integration of the vehicle. Attached Figure Description

[0044] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below, forming part of the present invention. The illustrative embodiments of the present invention and their descriptions explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0045] Figure 1 This is a structural block diagram of a dual electric drive bridge temperature control system provided in one embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram of the structural connection of a thermal management circuit provided in one embodiment of the present invention;

[0047] Figure 3 A flowchart of a dual electric drive bridge temperature control method provided in one embodiment of the present invention;

[0048] Figure 4 This is a partial flowchart of a dual electric drive bridge temperature control method provided in one embodiment of the present invention. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. In the description of this invention, it should be noted that the term "or" is generally used to include the meaning of "and / or," unless otherwise expressly indicated.

[0050] Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0051] Traditional electric drive axle temperature control systems typically employ simple heat dissipation and cooling methods, which cannot achieve precise temperature regulation. This often leads to problems such as slow temperature rise at low temperatures and insufficient heat dissipation at high temperatures. Furthermore, in dual electric drive axle systems, differences in workload and cooling conditions between the two axles can easily result in an imbalance where one axle is overheated while the other is underheated. Additionally, in existing technologies, the heat generated by dual electric drive axles is often directly dissipated into the environment, failing to coordinate heat management with other vehicle systems and resulting in energy waste.

[0052] refer to Figure 1To solve the problems in the prior art, embodiments of the present application provide a double electric drive axle temperature control system 100, which is preferably applicable to new energy commercial vehicles, such as electric trucks, electric buses, electric transport vehicles, electric tractors, etc., which are equipped with two electric drive axles. Preferably, the two electric drive axles in the vehicle are a middle electric drive axle and a rear electric drive axle. Specifically, the double electric drive axle temperature control system 100 at least includes a temperature acquisition unit 110, a thermal management circuit 120, a heat pump unit 130, and a main control unit 140. The two electric drive axles each include a motor, a gearbox, and a motor controller. In this embodiment, the specific structure of the electric drive axle is not specifically limited, and those skilled in the art can select any electric drive axle structure disclosed in the prior art as needed.

[0053] In an embodiment of the present application, the temperature acquisition unit 110 is arranged in the middle electric drive axle and the rear electric drive axle, respectively, for detecting the oil temperature in the two electric drive axles and transmitting the temperature to the main control unit 140. The thermal management circuit 120 includes a coolant storage unit 121, a water pump unit 122, a three-way valve unit 123, and a heat exchange unit 124. The heat exchange unit 124 is at least partially arranged on the two electric drive axles to warm or cool the two electric drive axles when the coolant flows through. The heat pump unit 130 is in communication with the heat exchange unit 124 and can transfer the heat of the two electric drive axles to the air conditioning system in the vehicle or the power battery under preset conditions. The main control unit 140 is electrically connected to the temperature acquisition unit 110, the water pump unit 122, the three-way valve unit 123, and the heat pump unit 130, respectively, for controlling the flow of the water pump unit 122 and the opening of the three-way valve unit 123 according to the oil temperature, adjusting the coolant flow into the heat exchange unit 124, and / or controlling the output torque distribution ratio of the double electric drive axle, and / or controlling the working state of the heat pump unit 130, so that the oil temperature of the two electric drive axles is maintained within a preset temperature range, thereby improving the energy consumption performance of the vehicle and providing the best driving state.

[0054] In an embodiment of the present application, the temperature acquisition unit 110 is configured as a plurality of temperature sensors. The type or specification / model of the temperature sensor is not specifically limited here, and those skilled in the art can make adaptive adjustments according to actual needs. Preferably, the temperature sensor is arranged at the motor, the gearbox, and the bearing of the middle electric drive axle and the rear electric drive axle for real-time detection of temperature changes at each location. In addition, the temperature sensor can also be arranged at the inlet and outlet of the heat exchange unit 124 for monitoring the inlet and outlet temperatures of the coolant, thereby obtaining real-time data of the heat exchange efficiency.

[0055] In an embodiment of the present application, the cooling liquid storage unit 121 is configured as a cooling liquid storage tank for storing cooling liquid required for system circulation and buffering the expansion and contraction of the cooling liquid volume when the temperature of the cooling liquid changes. Specifically, the specific type of cooling liquid in this embodiment is not limited, and those skilled in the art can select it according to the actual application scenario.

[0056] With reference to Figure 2 In an embodiment of the present application, the water pump unit 122 is arranged between the cooling liquid storage unit 121 and the three-way valve unit 123, and the water pump unit 122 is an electronic water pump for driving the circulation of the cooling liquid in the system. By adjusting the speed of the water pump, the flow rate of the cooling liquid can be controlled, thereby affecting the heat exchange efficiency. When it is necessary to improve the heat exchange efficiency, the speed of the water pump is increased to increase the flow rate; when it is necessary to reduce the heat exchange efficiency, the speed of the water pump is reduced to reduce the flow rate. The start and stop of the water pump and the speed of the water pump are adjusted by the controller

[0057] In an embodiment of the present application, the three-way valve unit 123 is configured as an electrically controlled three-way water valve having one inlet and two outlets, the two outlets being defined as a first outlet and a second outlet, respectively. The inlet of the three-way valve unit 123 is in communication with the outlet of the water pump unit 122, the first outlet is in communication with the heat exchange unit 124, and the second outlet is in communication with the cooling liquid storage unit 121 loop as a bypass pipeline, such as Figure 2 The opening degrees of the first outlet and the second outlet can be adjusted, and by controlling the opening degree ratio of the two outlets, the flow rate distribution of the cooling liquid flowing to the heat exchange unit 124 and the bypass pipeline can be adjusted. When it is necessary to increase the heat exchange effect, the opening degree of the first outlet is increased, and when it is necessary to reduce the heat exchange, the opening degree of the second outlet is increased to make the cooling liquid circulate directly through the bypass pipeline.

[0058] In an embodiment of the present application, the heat exchange unit 124 includes a first heat exchange unit, a second heat exchange unit, and a third heat exchange unit in sequence. Specifically, all of them adopt a plate heat exchanger structure, and the plate heat exchanger is internally provided with multiple layers of heat exchange channels. The cooling liquid and the lubricating oil flow in opposite directions in adjacent channels and exchange heat through metal sheets.

[0059] In an embodiment of the present application, the first heat exchange unit is arranged on the motor controller for heat dissipation of the controller, the second heat exchange unit is arranged on the motor for cooling of the motor winding, and the third heat exchange unit is arranged on the transmission for temperature adjustment of the transmission oil. The cooling liquid can flow through the first heat exchange unit, the second heat exchange unit, and the third heat exchange unit in sequence.

[0060] Specifically, since the motor controller is sensitive to temperature, the working temperature thereof needs to be ensured in priority, and therefore the first heat exchange unit is arranged at the most upstream position, at which the cooling liquid has the lowest temperature and the heat exchange effect is the best; the second heat exchange unit is arranged at the middle position, and the cooling liquid that has been heated can be used to heat the gearbox oil; the third heat exchange unit is used for temperature adjustment of the gearbox oil, and the temperature requirement thereof is relatively loose, and therefore the third heat exchange unit is arranged at the most downstream position. The serial arrangement of the heat exchange units 124 not only ensures the temperature control requirements of the components, but also improves the heat utilization efficiency of the system.

[0061] In an embodiment of the present application, a flow sensor is further arranged in the thermal management circuit 120, and the flow sensor is electrically connected with the main control unit 140 and used for detecting the flow of the cooling liquid; specifically, the flow sensor can be arranged at the outlet of the water pump unit 122 and used for monitoring the flow of the cooling liquid in real time, and then converting the detected flow signal into an electric signal and transmitting the electric signal to the main control unit 140, and the main control unit 140 compares the signal with a target flow to close-loop control the rotating speed of the water pump unit 122.

[0062] In an embodiment of the present application, the heat pump unit 130 includes a refrigerant circuit and a plate heat exchanger, one side of the plate heat exchanger is in thermal communication with the heat exchange unit 124, and the other side of the plate heat exchanger is in communication with the refrigerant circuit; the refrigerant circuit includes a compressor, a first condenser, a second condenser, a throttling element and an evaporator, the first condenser is in thermal communication with the in-vehicle air conditioning system, the second condenser is in thermal communication with the power battery, and the evaporator exchanges heat with the heat exchange unit 124 through the plate heat exchanger. When the in-vehicle air conditioning system or the power battery has a heating demand, the heat pump unit 130 can direct the heat generated by the double electric drive axle to realize heat recycling between systems.

[0063] Specifically, the heat generated during the operation of the double electric drive axle is transmitted to the cooling liquid through the heat exchange unit 124, and heat exchanged with the refrigerant through the plate heat exchanger, so that the refrigerant absorbs heat and vaporizes, and the gaseous refrigerant is compressed into superheated steam under the action of the compressor, and then enters the first condenser and the second condenser.

[0064] When heating is needed in the vehicle, the high-temperature refrigerant exchanges heat with the heat exchange medium of the air conditioning system in the first condenser to release heat for heating the cabin; when the power battery needs to be heated in a low-temperature state, the refrigerant exchanges heat with the battery cooling liquid in the second condenser to heat the battery. The condensed refrigerant is depressurized by the throttling element and then exchanges heat with the heat of the double electric drive axle through the evaporator, and the cycle is repeated.

[0065] Through the directional transfer of heat, not only the heat dissipation efficiency of the electric drive axle can be improved, but also the energy consumption of the vehicle air conditioning system and the power battery heating can be reduced, and the energy utilization efficiency of the vehicle can be improved. When the vehicle is in a cold environment, this heat collaborative management mode has a significant energy-saving effect.

[0066] In another embodiment of the present application, the heat pump unit 130 can also switch between refrigeration and heating by adjusting the flow direction of the refrigerant. Specifically, the refrigerant circuit is also provided with a four-way reversing valve and a plurality of electromagnetic valves. By controlling the reversing of the four-way reversing valve and the opening and closing of the electromagnetic valves, the flow direction of the refrigerant can be changed, thereby realizing the switching of different working modes.

[0067] For example, when the vehicle air conditioning system needs to be cooled and the power battery needs to be heated, part of the high-temperature refrigerant enters the second condenser to heat the power battery after being compressed by the compressor, and the other part enters the first condenser (which acts as an evaporator) after being throttled to cool the vehicle. At the same time, the heat generated by the two electric drive axles can still be absorbed by the refrigerant through the plate heat exchanger to realize the recycling of waste heat.

[0068] This switchable heat pump system can flexibly adjust the flow direction of heat according to the temperature requirements of different components of the vehicle, and can realize optimal heat distribution under different working conditions, further improving the adaptability and energy utilization efficiency of the system.

[0069] In an embodiment of the present application, the functions of the main control unit 140 are realized by the vehicle controller (VCU). In the temperature control process of the double electric drive axle, the VCU acquires the oil temperature signal obtained by the temperature sensor and the flow signal obtained by the flow sensor in real time through the CAN bus, and executes the temperature control strategy based on the real-time working condition.

[0070] Specifically, based on the collected signals, the main control unit 140 determines the target flow required by the water pump unit 122, the target opening of the three-way valve unit 123, and the target torque distribution ratio of the double electric drive axle in combination with the pre-set flow-opening-oil temperature correlation model. Subsequently, the main control unit 140 issues corresponding control instructions to the water pump controller, the three-way valve controller and the double electric drive axle controller respectively, realizing the collaborative control of each execution component.

[0071] At the same time, the main control unit 140 is also responsible for the management of the heat pump system, and schedules the heat pump unit 130 to recover waste heat and distribute heat according to the temperature requirements of the vehicle air conditioning system and the power battery. Through the unified scheduling of the main control unit 140, the collaborative control of the vehicle thermal management system is realized, and the operation efficiency of the system is improved.

[0072] Further, based on the above-mentioned double electric drive axle temperature control system 100, the embodiment of the present application further discloses a double electric drive axle temperature control method, and the execution subject of the control method is the master control unit 140 in the above-mentioned embodiment, and the technical features already included in the above-mentioned embodiment are naturally inherited in the following control method embodiment, and will not be described one by one. As Figure 3 The control method at least includes steps S210-S240.

[0073] Step S210, acquiring the temperature signal of the temperature acquisition unit in real time.

[0074] In an embodiment of the present application, the temperature signals of the electric drive axle oil temperature sensor and the rear electric drive axle oil temperature sensor are collected, which are used to acquire the real-time oil temperature data of the two electric drive axles. At the same time, the temperature signals of the temperature sensors at the inlet and outlet of the heat exchange unit 124 are collected, which are used to monitor the temperature change of the cooling liquid before and after heat exchange. The master control unit 140 performs filtering processing on the collected temperature signals to eliminate the influence of signal noise and improve the accuracy of the temperature data.

[0075] During the collection process, the master control unit 140 also performs validity judgment on the temperature signal. When it is detected that the signal of a certain temperature sensor is abnormal (such as signal interruption, value out of range, etc.), the master control unit 140 can start a backup strategy to estimate the temperature value at this place through the signals of other temperature sensors, so as to ensure that the system can continuously and reliably operate.

[0076] The collected temperature signal will be used as an input parameter of the subsequent control strategy, which is used to judge the working state of the double electric drive axle and determine the corresponding control measures.

[0077] Step S220, judging whether the oil temperature of the double electric drive axle is within a preset temperature range based on the temperature signal.

[0078] In an embodiment of the present application, it is first judged whether the oil temperature of the middle electric drive axle and the rear electric drive axle is within a preset temperature range, and the preset temperature range is preferably 80-90℃, which is the best working temperature interval of the electric drive axle. When the oil temperature is lower than 80℃, it is determined to be a low-temperature state, at which time the viscosity of the gearbox oil is larger, which will increase the mechanical loss. When the oil temperature is higher than 90℃, it is determined to be a high-temperature state, which may affect the working reliability of the electric drive axle.

[0079] In an embodiment of the present application, it is also necessary to calculate the temperature difference between the middle electric drive axle and the rear electric drive axle. When the temperature difference exceeds a preset threshold (such as 10℃), it is determined that the double electric drive axle is in a temperature imbalance state, and the temperature needs to be balanced by adjusting the torque distribution ratio.

[0080] In an embodiment of the present application, the master control unit 140 can also combine the working condition information such as vehicle speed and torque demand to predict the temperature change trend of the double electric drive axle, and provide decision basis for subsequent control strategy. For example, in the case of continuous high torque, even if the current oil temperature is in the normal range, appropriate temperature control measures need to be taken in advance.

[0081] Step S230, according to the judgment result, determine the target flow of the water pump unit, the target opening of the three-way valve unit, and the target output torque distribution ratio of the double electric drive axle.

[0082] In an embodiment of the present application, when the oil temperature is lower than the first preset temperature, the vehicle may be in the starting stage at this time, the water pump unit 122 is controlled to reduce the target flow, and / or the three-way valve unit 123 is controlled to increase the target opening of the first outlet; preferably, the first preset temperature is the coolant temperature, in order to make the coolant fully heated when passing through the motor, on the one hand, the water pump speed is reduced to reduce the coolant flow, and the heat exchange time is prolonged, on the other hand, the three-way valve first outlet opening is increased to ensure more coolant passing through the heat exchange unit 124, improve the heat exchange efficiency, and accelerate the warming speed of the gearbox oil.

[0083] Further, "controlling the water pump unit 122 to reduce the target flow, and / or controlling the three-way valve unit 123 to increase the target opening of the first outlet" specifically refers to: the water pump flow can be reduced only, the three-way valve first outlet opening can be increased only, or both adjustments are performed at the same time. The selection of the adjustment mode depends on the current temperature state and the warming demand, for example, when rapid warming is required, both adjustments can be performed at the same time to obtain the best warming effect, when the warming demand is not urgent, only one of the adjustments can be performed.

[0084] In an embodiment of the present application, when the oil temperature reaches the first preset temperature, the three-way valve unit 123 is controlled to reduce the target opening of the first outlet until it is closed, and the second outlet is kept open; specifically, when the oil temperature reaches the first preset temperature, it indicates that the coolant temperature is insufficient to heat the gearbox oil, at this time, the three-way valve first outlet is completely closed, and the coolant is circulated directly through the second outlet, avoiding the coolant taking away the heat of the electric drive axle, and realizing the rapid rising of the oil temperature.

[0085] In one embodiment of the present application, when the oil temperature reaches the second preset temperature, the three-way valve unit 123 is controlled to increase the target opening degree of the first outlet, and / or the water pump unit 122 is controlled to increase the target flow rate; preferably, the second preset temperature is a safety threshold temperature of the oil temperature, such as 85°C, when the temperature reaches this temperature, the heat dissipation needs to be strengthened, at this time, the three-way valve first outlet opening degree is increased, and the water pump flow rate is increased to strengthen the heat exchange circulation of the coolant; preferably, when the water pump unit 122 and the three-way valve unit 123 are adjusted, the target flow rate and the target opening degree are synchronously adjusted based on the preset flow rate-opening degree-oil temperature correlation model, so as to realize accurate control of the oil temperature.

[0086] Further, "controlling the three-way valve unit 123 to increase the target opening degree of the first outlet, and / or controlling the water pump unit 122 to increase the target flow rate" specifically means that the three-way valve first outlet opening degree can be increased alone, the water pump flow rate can be increased alone, or both can be adjusted. The specific adjustment mode is determined based on the preset flow rate-opening degree-oil temperature correlation model, for example, when the temperature is slightly higher than the target value, only one parameter needs to be adjusted, and when the temperature significantly exceeds the target value, both parameters need to be adjusted to strengthen the heat dissipation effect.

[0087] In one embodiment of the present application, the preset flow rate-opening degree-oil temperature correlation model is established based on the mapping relationship among the prior oil temperature, the target flow rate and the three-way valve opening degree. In one optional embodiment, when the oil temperature is in the range of 85°C-90°C, the following configuration can be made:

[0088] When the oil temperature is 85°C, the three-way valve first outlet opening degree is 20%, and the water pump flow rate is 60% of the reference flow rate;

[0089] When the oil temperature is 86°C, the three-way valve first outlet opening degree is 40%, and the water pump flow rate is 70% of the reference flow rate;

[0090] When the oil temperature is 87°C, the three-way valve first outlet opening degree is 60%, and the water pump flow rate is 80% of the reference flow rate;

[0091] When the oil temperature is 88°C, the three-way valve first outlet opening degree is 80%, and the water pump flow rate is 90% of the reference flow rate;

[0092] When the oil temperature is 89°C, the three-way valve first outlet opening degree is 90%, and the water pump flow rate is 95% of the reference flow rate;

[0093] When the oil temperature is 90°C, the three-way valve first outlet opening degree is 100%, and the water pump flow rate is 100% of the reference flow rate.

[0094] Wherein, the reference flow is the rated working flow of the water pump, for example, 50 L / min. When the oil temperature is between the above-mentioned set points, the corresponding opening value and flow value are calculated by linear interpolation. This stepwise adjustment mode not only ensures the stability of control, but also adjusts the heat dissipation intensity in time according to temperature changes.

[0095] Of course, the above-mentioned values are only preferred embodiments, and a person skilled in the art can adjust the specific parameters according to the actual application scene. By presetting the above-mentioned correlation model, the cooperative control of the water pump flow and the three-way valve opening can be realized in the temperature control process, so as to improve the accuracy of temperature control, and at the same time, the real-time calculation in the temperature control is avoided, so the timeliness of system response is also improved.

[0096] In an embodiment of the present application, step S230 further comprises:

[0097] When it is detected that the oil temperature difference of the double electric drive axle exceeds the preset threshold value, the target output torque distribution ratio is adjusted, so that the electric drive axle with higher oil temperature reduces the output torque, and the electric drive axle with lower oil temperature increases the output torque, until the oil temperatures of the two tend to balance.

[0098] Specifically, the main control unit 140 can calculate the oil temperature difference ΔT of the middle electric drive axle and the rear electric drive axle in real time, and when ΔT exceeds the preset threshold value (for example, 10℃), the torque redistribution strategy is started. Preferably, the current torque distribution ratio (the ratio of the middle electric drive axle torque to the total torque) is defined as K, and the target torque distribution ratio is defined as K'. The target torque distribution ratio K' can be calculated based on the current torque distribution ratio K and the oil temperature difference ΔT.

[0099] In an embodiment of the present application, when the oil temperature of the middle electric drive axle is higher than that of the rear electric drive axle, K' = K - a x ΔT; when the oil temperature of the rear electric drive axle is higher than that of the middle electric drive axle, K' = K + a x ΔT; wherein, a is an adjustment coefficient, which can be determined according to actual calibration.

[0100] Preferably, in order to ensure the power performance of the whole vehicle, when adjusting the torque distribution ratio, the change rate of torque adjustment does not exceed 5% / s, so as to avoid the influence of sudden change on driving feeling; when the vehicle speed exceeds 80km / h or the steering angle is greater than 30°, the torque redistribution is suspended. This dynamic distribution strategy based on temperature difference does not affect the driving feeling. It can ensure the temperature balance of the two electric drive axles (prevent single axle over-temperature), and at the same time, it can improve the power performance and adaptability of working conditions.

[0101] In an embodiment of the present application, step S230 further comprises a protection control strategy for single axle temperature overrun:

[0102] When the oil temperature of a certain electric drive axle is detected to exceed the maximum safety threshold (e.g. 95℃), the temperature protection strategy is triggered: first, the output torque of the electric drive axle is immediately reduced, and the torque limitation coefficient decreases with the temperature rise; at the same time, the load is transferred to the electric drive axle with normal temperature.

[0103] Specifically, for the vehicle model with the same power dual electric drive axle configuration, the temperature balance strategy is mainly used for adjustment, that is, when the oil temperature difference is detected to exceed the preset threshold, the temperature balance is achieved by adjusting the target output torque distribution ratio. When in single axle driving state or encountering large load working conditions (e.g. climbing), if the single axle oil temperature exceeds 95℃, the temperature protection strategy is triggered to limit the output torque of the electric drive axle.

[0104] For the vehicle model with different power dual electric drive axle configuration, due to the different rated power of the two electric drive axles, the adjustment range of the temperature balance strategy is limited, and about 50% of the temperature control needs to rely on the temperature protection strategy. When the high-power electric drive axle has a high temperature, if large torque output is needed at this time (e.g. climbing), the system will cooperatively use the temperature balance strategy and the temperature protection strategy: on the one hand, the torque output proportion of the low-power electric drive axle is increased, and on the other hand, the torque of the high-temperature electric drive axle is limited.

[0105] Through the cooperation of the double-layer control strategy, the demand of different power configurations can be met, and the single axle over-temperature in large load working conditions can be effectively avoided, ensuring the reliable operation of the system and the vehicle power performance.

[0106] Step S240, the temperature adjustment control execution effect of the dual electric drive axle is monitored, and the target flow, and / or the target opening, and / or the target output torque ratio is dynamically adjusted according to the change trend of the temperature signal until the oil temperature returns to the preset temperature range.

[0107] In an embodiment of the present application, the master control unit 140 analyzes the temperature data in the sampling period, calculates the change rate and trend of the temperature, judges the change state of the current temperature based on the sliding average calculation of the historical temperature data, and provides a basis for subsequent dynamic adjustment. In this embodiment, the specific value of the sampling period is no longer limited, and it can be freely set by the person skilled in the art as needed.

[0108] In an embodiment of the present application, when the temperature shows an upward trend, corresponding control measures are taken according to the different rising rates, including increasing the flow of the water pump unit 122, increasing the opening of the first outlet in the three-way valve unit 123, adjusting the target torque distribution ratio, etc.; when the temperature shows a downward trend and approaches the lower limit of the preset range, the flow of the water pump unit 122 and the opening of the three-way valve unit 123 are correspondingly reduced, and the default torque distribution state is gradually restored; when the temperature is in a stable state and within the preset range, the current control parameters remain unchanged, and the trend monitoring continues.

[0109] During the adjustment process, the main control unit 140 continuously monitors the adjustment effect until the oil temperature returns to the preset temperature range, and the temperature change trend is stable, and the temperature difference between the two electric drive axles is within the allowable range. Through this closed-loop monitoring and adjustment mechanism, the accuracy and reliability of temperature control can be ensured.

[0110] As Figure 4 In an embodiment of the present application, the dual electric drive axle temperature control method further comprises steps S310-S330.

[0111] Step S310, obtain the working state signals of the in-vehicle air conditioning system and the power battery, and the temperature signals of the dual electric drive axle.

[0112] In an embodiment of the present application, the working state signals of the in-vehicle air conditioning system include the working mode, target temperature, and current temperature of the air conditioning system; the working state signals of the power battery include the temperature and heating demand of the power battery; and the temperature signals of the dual electric drive axle include the oil temperature and coolant temperature of the two electric drive axles.

[0113] Step S320, when the preset heat pump starting condition is met, start the heat pump unit to control the heat pump unit to transfer the heat of the dual electric drive axle to the in-vehicle air conditioning system or the power battery.

[0114] In an embodiment of the present application, when the oil temperature of the dual electric drive axle is higher than the preset temperature (such as 85℃), the in-vehicle air conditioning system is in a heating demand state or the temperature of the power battery is lower than the optimal working temperature, and the vehicle is in a normal driving state, the heat pump unit 130 is started to transfer the heat of the dual electric drive axle through the refrigerant circuit.

[0115] Step S330, determine the priority of the heat transfer object based on the working state signals and the temperature signals, and perform corresponding heat transfer control.

[0116] In an embodiment of the present application, the determination principle of the heat transfer priority is: when the temperature of the power battery is lower than the safe working temperature, the power battery is preferentially heated; when the passenger compartment has a heating demand and the temperature of the power battery is within the safe range, the in-vehicle heating is preferentially performed; when the temperature of the dual electric drive axle approaches the upper limit, double heat transfer can be performed simultaneously.

[0117] Through this heat transfer strategy based on priority, the rational allocation and efficient utilization of vehicle heat are realized, and the overall energy efficiency of the system is improved.

[0118] In specific embodiments of the present application, the temperature control strategies for different application scenarios are as follows:

[0119] When the vehicle is in an urban road working condition, during frequent start-stop and acceleration-deceleration processes, the temperature of the double electric drive axle gradually rises. When the oil temperature is detected to reach the second preset temperature, the main control unit 140 synchronously adjusts the three-way valve opening degree and the water pump flow to enhance heat dissipation based on the flow-opening-oil temperature correlation model. At the same time, due to the frequent start-stop of the vehicle in the congested working condition, the temperature difference between the two electric drive axles may occur. At this time, the main control unit 140 adjusts the target output torque distribution ratio to reduce the output torque of the electric drive axle with higher oil temperature and increase the output torque of the electric drive axle with lower oil temperature until the oil temperatures of the two electric drive axles tend to be balanced. In addition, when the heat pump starting condition is met, the main control unit 140 controls the heat pump unit 130 to transfer the heat generated by the double electric drive axle to the vehicle interior air conditioning system to improve energy utilization efficiency.

[0120] When the vehicle is in a highway working condition, the main control unit 140 continuously monitors the temperature signals of the double electric drive axle. When the oil temperature reaches the second preset temperature, the target flow and the target opening degree are dynamically adjusted based on the temperature change trend. At the same time, in order to improve the endurance mileage, the main control unit 140 optimizes the torque distribution strategy to reduce the system energy consumption under the premise of ensuring temperature balance. When the environmental temperature is low, the main control unit 140 judges whether the heat pump starting condition is met. If necessary, the heat of the double electric drive axle is transferred to the power battery to improve the battery performance.

[0121] When the vehicle is in a mountain road working condition, due to frequent climbing and descending, the load of the double electric drive axle changes greatly, causing the oil temperature to fluctuate obviously. The main control unit 140 monitors the temperature signals in real time. When it is detected that the oil temperature of a certain electric drive axle is too high, the target output torque distribution ratio is adjusted, and the flow of the water pump unit 122 is increased to enhance heat dissipation. During the descending process, when the heat pump starting condition is met, the main control unit 140 controls the heat pump unit 130 to transfer the heat of the double electric drive axle to the vehicle interior air conditioning system to improve energy utilization efficiency.

[0122] When the vehicle is in a cold weather working condition, at the start of the vehicle, the temperatures of the double electric drive axle and the power battery are both low. At this time, the main control unit 140 controls the heat pump unit 130 to start to transfer the heat of the environment or other heat sources to the double electric drive axle and the power battery for preheating. At the same time, the first outlet of the three-way valve is controlled to be closed to reduce the flow of the cooling liquid and avoid excessive cooling. After the temperature reaches the first preset temperature, the system enters the normal control mode. The main control unit 140 dynamically adjusts the control parameters based on the change trend of the temperature signals to ensure the reliable operation of the system in the low-temperature environment.

[0123] In an embodiment of the present application, a new energy commercial vehicle configured with two electric drive axles is also provided. The vehicle is provided with the above-mentioned double electric drive axle temperature control system 100 and can perform the above-mentioned double electric drive axle temperature control method.

[0124] The embodiment of the present application further provides an electronic device, which comprises a memory and a processor, and the memory stores a computer program which is run by the processor, and the computer program enables the processor to execute the double-motor-bridge temperature control method as described above when the computer program is run by the processor. Various application programs and various data, for example, various data used and / or generated by the application programs, etc. can also be stored in the memory. The processor can be a central processing unit (CPU), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other forms of processing units having data processing and / or instruction execution capabilities.

[0125] The embodiment of the present application further provides a computer readable storage medium, which stores a computer program which is run by a processor, and the computer program enables the processor to execute the double-motor-bridge temperature control method as described above when the computer program is run by the processor. Exemplarily, the computer readable storage medium can comprise a memory card of a smart phone, a memory component of a tablet computer, a hard disk of a personal computer, a read only memory (ROM), an erasable programmable read only memory (EPROM), a compact disc read only memory (CD-ROM), a USB memory, or any combination of the above storage mediums. The computer readable storage medium can be any combination of one or more computer readable storage mediums.

[0126] Although the example embodiments have been described herein with reference to the accompanying drawings, it is to be understood that the example embodiments are only exemplary and are not intended to limit the scope of the present application. Various changes and modifications can be made thereto by those of ordinary skill in the art without departing from the scope and spirit of the present application. All such changes and modifications are intended to be included within the scope of the present application as claimed in the appended claims.

[0127] In the specification provided herein, a large number of specific details are described. However, it can be understood that the embodiments of the present application can be practiced without these specific details. In some examples, well-known methods, structures and techniques are not shown in detail in order not to obscure the understanding of the present specification.

[0128] Similarly, it is to be understood that the embodiments of the present application can alternately be phrased or described substantially similarly to what is claimed by one skilled in the art. Thus, the foregoing detailed description of the embodiments of the application, given by way of example above, is not to be construed in a limiting sense, but is made merely to provide a specific description of certain embodiments of the application. Accordingly, there are many alternatives, modifications, and variations to which the present application is capable of being directed. Thus, what is desired to be protected by letters patent is set forth and supported by what is described in the above specification and attachments, as well as the appended claims, in which all terms are to be interpreted broadly under the doctrine of equivalents.

[0129] Those skilled in the art will appreciate that all features could be substituted with alternative features serving the same, equivalent, or similar purposes, and that many such alternatives will be or become apparent to the skilled person in the light of the disclosure provided herein. Accordingly, any apparently

[0130] The embodiments of the application described above are intended to be illustrative only and in no way limit the scope of the application. Those skilled in the art will be able to devise many alternative embodiments without departing from the scope of the application. The described embodiments are to be considered in a descriptive sense only and not limiting. Therefore, the scope of the application is indicated by the appended claims, rather than by the foregoing description, and all changes that come within the meaning and range of equivalents are intended to be embraced therein.

Claims

1. A dual electric drive axle temperature control system, comprising: The application relates to a temperature acquisition unit arranged in at least one double electric drive axle for detecting the oil temperature of the double electric drive axle; a heat management circuit comprising a cooling liquid storage unit, a water pump unit, a three-way valve unit and a heat exchange unit, the heat exchange unit being arranged at least partially on the double electric drive axle, the water pump unit being arranged between the cooling liquid storage unit and the three-way valve unit, the inlet of the three-way valve unit being communicated with the outlet of the water pump unit, the first outlet of the three-way valve unit being communicated with the heat exchange unit, and the second outlet of the three-way valve unit being communicated with the cooling liquid storage unit; a heat pump unit in thermal communication with the heat exchange unit for transferring the heat of the double electric drive axle to an air conditioning system or a power battery under a preset condition; and a main control unit electrically connected with the temperature acquisition unit, the water pump unit, the three-way valve unit and the heat pump unit for controlling the flow of the water pump unit and the opening of the three-way valve unit according to the oil temperature to adjust the flow of the cooling liquid entering the heat exchange unit, and / or controlling the output torque distribution ratio of the double electric drive axle, and / or controlling the working state of the heat pump unit, so that the oil temperature of the double electric drive axle is maintained within a preset temperature range. The double electric drive axle comprises a motor, a gearbox and a motor controller. The heat exchange unit comprises a first heat exchange unit, a second heat exchange unit and a third heat exchange unit communicated in sequence, wherein the first heat exchange unit is arranged on the motor controller, the second heat exchange unit is arranged on the motor, and the third heat exchange unit is arranged on the gearbox; and the cooling liquid can flow through the first heat exchange unit, the second heat exchange unit and the third heat exchange unit in sequence. The heat management circuit further comprises a flow sensor electrically connected with the main control unit for detecting the flow of the cooling liquid. The heat pump unit comprises a refrigerant circuit and a plate heat exchanger.

2. The dual electric drive axle temperature control system of claim 1, wherein, One side of the plate heat exchanger is in thermal communication with the heat exchange unit, and the other side is in communication with the refrigerant circuit. The refrigerant circuit comprises a compressor, a first condenser, a second condenser, a throttling element and an evaporator, the first condenser is in thermal communication with the air conditioning system, the second condenser is in thermal communication with the power battery, and the evaporator exchanges heat with the heat exchange unit through the plate heat exchanger.

3. The dual electric drive axle temperature control system of claim 1, wherein, The application further relates to a method for controlling the temperature of a double electric drive axle.

4. The dual electric drive axle temperature control system of claim 1, wherein, The method comprises the following steps: acquiring the temperature signal of the temperature acquisition unit in real time; judging whether the oil temperature of the double electric drive axle is within a preset temperature range based on the temperature signal; determining the target flow of the water pump unit, the target opening of the three-way valve unit and the target output torque distribution ratio of the double electric drive axle according to the judgment result; monitoring the execution effect of the temperature adjustment control of the double electric drive axle, and dynamically adjusting the target flow, the target opening and / or the target output torque ratio according to the change trend of the temperature signal until the oil temperature returns to the preset temperature range. The method further comprises the following steps: acquiring the working state signal of the air conditioning system and the power battery and the temperature signal of the double electric drive axle. ​ 5. A method of controlling the temperature of a dual electric drive axle using the system of any one of claims 1-4, wherein, ​ ​ ​ ​ ​ 6. The dual electric drive axle temperature control method of claim 5, wherein, ​ ​ When a preset heat pump starting condition is met, a heat pump unit is started, and the heat pump unit is controlled to transfer heat of the double electric drive axle to the vehicle interior air conditioning system or the power battery; A priority of a heat transfer object is determined based on the working state signal and the temperature signal, and a corresponding heat transfer control is performed.

7. The dual electric drive axle temperature control method of claim 5, wherein, In the step of determining the target flow of the water pump unit, the target opening degree of the three-way valve unit, and the target output torque distribution ratio of the double electric drive axle according to the judgment result, the following is included: When the oil temperature is lower than a first preset temperature, the water pump unit is controlled to reduce the target flow, and / or the three-way valve unit is controlled to increase the target opening degree of the first outlet; When the oil temperature reaches the first preset temperature, the three-way valve unit is controlled to reduce the target opening degree of the first outlet until the first outlet is closed, and the second outlet is kept open; When the oil temperature reaches a second preset temperature, the three-way valve unit is controlled to increase the target opening degree of the first outlet, and / or the water pump unit is controlled to increase the target flow; The first preset temperature is lower than the second preset temperature.

8. The dual electric drive axle temperature control method of claim 7, wherein, In the step of determining the target flow of the water pump unit, the target opening degree of the three-way valve unit, and the target output torque distribution ratio of the double electric drive axle according to the judgment result, the following is included: The target flow and the target opening degree are synchronously adjusted based on a preset flow-opening-oil temperature correlation model.

9. The dual electric drive axle temperature control method of claim 5, wherein, In the step of determining the target flow of the water pump unit, the target opening degree of the three-way valve unit, and the target output torque distribution ratio of the double electric drive axle according to the judgment result, the following is included: When it is detected that an oil temperature difference of the double electric drive axle exceeds a preset threshold, the target output torque distribution ratio is adjusted, so that the electric drive axle with higher oil temperature reduces the output torque, and the electric drive axle with lower oil temperature increases the output torque, until the oil temperatures of the two electric drive axles tend to be balanced.

10. A vehicle characterized by comprising: The double electric drive axle temperature control system includes any one of claims 1-4.

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