Double-electric-drive-axle temperature control system and method and vehicle

Abstract

The invention relates to a double-electric-drive-axle temperature control system and method and a vehicle. The system comprises a temperature collecting unit, a heat management loop, a heat pump unit and a main control unit. The temperature acquisition unit is at least arranged in the double-electric-drive bridge; the heat 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 double-electric-drive bridge, and 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 double-electric-drive axle to an in-vehicle air conditioning system or a power battery under a preset condition; the main control unit is electrically connected with the above units and used for controlling the flow of the water pump unit and the opening degree of the three-way valve unit according to the oil temperature so as to adjust the flow of cooling liquid entering the heat exchange unit and / or controlling the output torque distribution ratio of the double-electric-drive bridge and / or controlling the working state of the heat pump unit. And the oil temperature of the double-electric-drive axle is maintained within the preset temperature range.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal management systems for electric drive axles of new energy commercial vehicles, and in particular to a temperature control system, method and vehicle for dual electric drive axles. Background Art

[0002] At present, pure electric heavy-duty trucks are in the transition stage from the traditional fuel vehicle "oil to electricity" to the pure electric proprietary platform upgrade. In terms of drive form, some manufacturers adopt dual-motor drive solutions based on economic considerations, while the more advanced technical route is to adopt a distributed drive dual electric drive axle solution. The dual electric drive axle realizes vehicle operation through independent control of the front and rear axles, providing better energy consumption performance while ensuring power.

[0003] The electric drive axle is a powertrain component that integrates a motor, a reducer, and a differential. Lubricating oil is required inside the axle to lubricate and cool the gear set and bearings. The transmission efficiency of the electric drive axle is closely related to the temperature of the lubricating oil inside it. Generally speaking, the optimal operating temperature range of the electric drive axle is 80-90°C. However, the existing technology has at least the following defects:

[0004] 1) The cooling system of the existing electric drive axle adopts a straight-through water cooling structure. The cooling water continuously takes away heat from the oil heat exchange plate, resulting in the oil temperature of the electric drive axle only reaching about 70°C even under heavy load conditions and an ambient temperature of 40°C;

[0005] 2) Due to its highly integrated characteristics, the electric drive axle has a greater passive heat dissipation capacity than traditional axles, further exacerbating the problem of low oil temperature;

[0006] 3) The oil temperature is continuously lower than the optimal working range, resulting in excessively high viscosity of the lubricating oil, increased mechanical losses, increased energy consumption of the vehicle, and decreased driving efficiency.

[0007] Based on the above defects, how to increase 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 energy consumption of the whole vehicle has become a technical problem that needs to be solved urgently. Summary of the invention

[0008] The present invention discloses a dual electric drive axle temperature control system, method and vehicle, aiming to solve the technical problems existing in the prior art.

[0009] The present invention adopts the following technical solutions:

[0010] In a first aspect, an embodiment of the present invention provides a dual electric drive bridge temperature control system, the system comprising:

[0011] - a temperature collection unit, which is at least arranged in the dual electric drive axle and is used to detect the oil temperature of the dual electric drive axle respectively;

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

[0013] - a heat pump unit, thermally connected to the heat exchange unit, for transferring the heat of the dual electric drive axle to the in-vehicle air conditioning system or the power battery under preset conditions;

[0014] - A main control unit, which is electrically connected to the temperature acquisition unit, the water pump unit, the three-way valve unit and the heat pump unit, respectively, and is used to control 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 coolant entering the heat exchange unit, and / or control the output torque distribution ratio of the dual electric drive axle, and / or control the working state of the heat pump unit to maintain the oil temperature of the dual electric drive axle within a preset temperature range.

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

[0016] The heat exchange unit includes a first heat exchange unit, a second heat exchange unit and a third heat exchange unit which are connected 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 thermal management circuit further includes a flow sensor, which is electrically connected to the main control unit and is used to detect the flow rate of the coolant.

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

[0019] One side of the plate heat exchanger is thermally connected to the heat exchange unit, and the other side is connected to the refrigerant circuit;

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

[0021] In a first aspect, an embodiment of the present invention provides a dual electric drive bridge temperature control method using a system as described in any one of the above items, characterized by comprising:

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

[0023] Based on the temperature signal, determining whether the oil temperature of the dual electric drive axle is within a preset temperature range;

[0024] According to the judgment result, 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 electric drive axle;

[0025] Monitor the temperature regulation control execution effect of the dual electric drive axle, and dynamically adjust the target flow, and / or 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.

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

[0027] Acquiring operating status signals of the in-vehicle air conditioning system and the power battery, and the temperature signal of the dual electric drive axle;

[0028] When a preset heat pump start-up condition is met, the heat pump unit is started, and the heat pump unit is controlled to transfer the heat of the dual electric drive axle to the in-vehicle air conditioning system or the power battery;

[0029] The priority of the heat transfer object is determined based on the working state signal and the temperature signal, and the corresponding heat transfer control is performed.

[0030] In some embodiments, the step of determining the target flow rate of the water pump unit, the target opening of the three-way valve unit, and the target output torque distribution ratio of the dual electric drive axle according to the judgment result includes:

[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 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 of the first outlet until it is closed, and keeping the second outlet open;

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

[0034] The first preset temperature is lower than the second preset temperature.

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

[0036] Based on a preset flow-opening-oil temperature correlation model, the target flow and the target opening are synchronously adjusted.

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

[0038] When it is detected that the oil temperature difference of the dual electric drive axles 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 are balanced.

[0039] In a third aspect, an embodiment of the present invention provides a vehicle, comprising a dual electric drive axle temperature control system as described in any one of the above items.

[0040] One embodiment of the above invention has the following advantages or beneficial effects:

[0041] The embodiment of the present invention mainly provides a dual electric drive axle temperature control system, method and vehicle. Compared with the prior art, the embodiment of the present invention realizes precise regulation of the oil temperature in the dual electric drive axle by establishing a closed-loop control system for the temperature of the dual electric drive axle; specifically, the heat exchange efficiency of the coolant can be improved by reducing the water pump flow and increasing the opening of the three-way valve in the low-temperature stage. After the oil temperature reaches the temperature of the coolant, the heat exchange channel of the three-way valve is closed for bypass, so that the oil temperature can quickly rise to the optimal operating temperature. After the oil temperature reaches the safety threshold temperature, the water pump flow and the three-way valve opening are dynamically adjusted based on a preset flow-opening-oil temperature association model to ensure that the dual electric drive axle always operates within the optimal temperature range.

[0042] In addition, the embodiment of the present invention also introduces a temperature balance control strategy between the dual electric drive axles. By real-time monitoring the temperature difference between the middle electric drive axle and the rear electric drive axle, the output torque distribution ratio of the two is dynamically adjusted, thereby avoiding the risk of excessive temperature of a single electric drive axle and improving the heat dissipation efficiency and energy utilization efficiency of the vehicle power system.

[0043] Furthermore, the embodiment of the present invention also integrates a heat pump system to achieve coordinated heat management of the dual electric drive axles, the vehicle's air-conditioning system, and the power battery: when the preset heat pump start-up conditions are met, the system can reasonably transfer the heat of the dual electric drive axles to objects with heating requirements, thereby improving the comprehensive utilization efficiency of the vehicle's thermal energy and improving the deep integration and unification of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments, which constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions explain the present invention and do not constitute improper limitations on the present invention. In the drawings:

[0045] Figure 1 A structural block diagram of a dual electric drive bridge temperature control system provided by an embodiment of the present invention;

[0046] Figure 2 A schematic diagram of the structural connection of a thermal management circuit provided by an embodiment of the present invention;

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

[0048] Figure 4 A partial flow chart of a dual electric drive axle temperature control method provided by one embodiment of the present invention. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. In the description of the present invention, it should be noted that the term "or" is usually used in the sense of including "and / or", unless the content clearly indicates otherwise.

[0050] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0051] Traditional electric drive axle temperature control systems usually use a simple heat dissipation cooling method, which cannot achieve precise temperature regulation, and easily lead to problems such as the electric drive axle heating up too slowly at low temperatures and insufficient heat dissipation at high temperatures. In addition, in a dual electric drive axle system, due to differences in the workload and heat dissipation conditions of the two electric drive axles, an unbalanced state in which one electric drive axle is too hot and the other is too cold is likely to occur. At the same time, the heat generated by the dual electric drive axles in the prior art is often directly dissipated into the environment, and the heat is not managed in coordination with other vehicle systems, resulting in energy waste.

[0052] refer to Figure 1In order to solve the deficiencies in the prior art, an embodiment of the present invention provides a dual electric drive axle temperature control system 100, which is preferably suitable for new energy commercial vehicles equipped with two electric drive axles, such as electric trucks, electric buses, electric transport vehicles, electric tractors, etc.; preferably, the two electric drive axles configured in the vehicle are the middle electric drive axle and the rear electric drive axle. Specifically, the dual electric drive axle temperature control system 100 includes at least a temperature acquisition unit 110, a thermal management circuit 120, a heat pump unit 130 and a main control unit 140; both electric drive axles include a motor, a gearbox and a motor controller. In this embodiment, the specific structure of the electric drive axle is no longer specifically limited, and those skilled in the art can select any electric drive axle structure disclosed in the prior art as needed.

[0053] In one embodiment of the present invention, the temperature acquisition unit 110 is at least arranged in the middle electric drive axle and the rear electric drive axle, and is used to detect the oil temperature in the two electric drive axles respectively, and transmit it 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, and the heat exchange unit 124 is at least partially arranged on the two electric drive axles, and when the coolant flows through, the two electric drive axles are heated or cooled; the heat pump unit 130 is connected to the heat exchange unit 124, and can transfer the heat of the two electric drive axles to the air in the vehicle 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, and is used to control the flow of the water pump unit 122 and the opening of the three-way valve unit 123 according to the oil temperature, so as to adjust the coolant flow entering the heat exchange unit 124, and / or control the output torque distribution ratio of the dual electric drive axles, and / or control the working state of the heat pump unit 130, so as to maintain the oil temperature of the two electric drive axles within a preset temperature range, thereby improving the energy consumption performance of the vehicle and providing the best driving state.

[0054] In one embodiment of the present invention, the temperature acquisition unit 110 is configured as several temperature sensors. The type or specification / model of the temperature sensor is not specifically limited here. Those skilled in the art can make adaptive adjustments according to actual needs. Preferably, the temperature sensors are arranged at the motors, gear boxes and bearings of the middle electric drive axle and the rear electric drive axle to detect temperature changes in various places in real time. In addition, the temperature sensor can also be arranged at the inlet and outlet of the heat exchange unit 124 to monitor the inlet and outlet temperatures of the coolant, so as to obtain real-time data of the heat exchange efficiency.

[0055] In one embodiment of the present invention, the coolant storage unit 121 is configured as a coolant storage tank, which is used to store the coolant required for system circulation and to buffer the expansion and contraction of the coolant volume when the coolant temperature changes. Specifically, the specific type of coolant is not limited in this embodiment, and those skilled in the art can select it according to the actual application scenario.

[0056] refer to Figure 2 In one embodiment of the present invention, the water pump unit 122 is disposed between the coolant storage unit 121 and the three-way valve unit 123. The water pump unit 122 is an electronic water pump, which is used to drive the coolant to circulate in the system. The flow rate of the coolant can be controlled by adjusting the speed of the water pump, thereby affecting the heat exchange efficiency. When the heat exchange efficiency needs to be improved, the water pump speed is increased to increase the flow rate; when the heat exchange efficiency needs to be reduced, the water pump speed is reduced to reduce the flow rate. The start and stop and speed of the water pump are all adjusted by the controller.

[0057] In one embodiment of the present invention, the three-way valve unit 123 is configured as an electrically controlled three-way water valve, which has an inlet and two outlets, the two outlets are defined as a first outlet and a second outlet, the inlet is connected to the outlet of the water pump unit 122, the first outlet is connected to the heat exchange unit 124, and the second outlet is connected to the coolant storage unit 121 circuit to serve as a bypass line. Figure 2 The openings of the first outlet and the second outlet are both adjustable. By controlling the opening ratio of the two outlets, the coolant flow distribution 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 of the first outlet is increased. When it is necessary to reduce the heat exchange, the opening of the second outlet is increased to allow the coolant to circulate directly through the bypass pipeline.

[0058] In one embodiment of the present invention, the heat exchange unit 124 includes a first heat exchange unit, a second heat exchange unit and a third heat exchange unit which are connected in sequence. Specifically, all three adopt a plate heat exchanger structure. A plurality of heat exchange channels are arranged inside the plate heat exchanger. The coolant and the lubricating oil flow in opposite directions in adjacent channels and exchange heat through metal plates.

[0059] In one embodiment of the present invention, a first heat exchange unit is disposed on a motor controller for heat dissipation of the controller, a second heat exchange unit is disposed on the motor for cooling the motor windings, and a third heat exchange unit is disposed on the gearbox for temperature regulation of the gearbox oil. The coolant 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 and its operating temperature needs to be guaranteed first, the first heat exchange unit is set at the most upstream position, where the coolant temperature is the lowest and the heat exchange effect is the best; the motor is the main heat source, and the second heat exchange unit is set in the middle position, which can make full use of the heated coolant to heat the gearbox oil; the third heat exchange unit is used for temperature regulation of the gearbox oil, and its temperature requirement is relatively loose, so it is set at the most downstream position. This series arrangement of the heat exchange unit 124 not only ensures the temperature control requirements of each component, but also improves the heat utilization efficiency of the system.

[0061] In one embodiment of the present invention, a flow sensor is also provided in the thermal management circuit 120, and the flow sensor is electrically connected to the main control unit 140 for detecting the flow rate of the coolant; specifically, the flow sensor can be arranged at the outlet of the water pump unit 122, for real-time monitoring of the flow rate of the coolant, and then converting the detected flow signal into an electrical signal and transmitting it to the main control unit 140. The main control unit 140 compares the signal with the target flow rate, thereby performing closed-loop control on the rotation speed of the water pump unit 122.

[0062] In one embodiment of the present invention, the heat pump unit 130 includes a refrigerant circuit and a plate heat exchanger, wherein one side of the plate heat exchanger is thermally connected to the heat exchange unit 124, and the other side is connected to 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 thermally connected to the in-vehicle air conditioning system, the second condenser is thermally connected to the power battery, and the evaporator exchanges heat with the heat exchange unit 124 through the plate heat exchanger. When there is a heating demand for the in-vehicle air conditioning system or the power battery, the heat pump unit 130 can transfer the heat generated by the dual electric drive axle in a directional manner to achieve heat recovery and utilization between systems.

[0063] Specifically, the heat generated during the operation of the dual electric drive axle is transferred to the coolant through the heat exchange unit 124, and heat is exchanged with the refrigerant through the plate heat exchanger, so that the refrigerant absorbs heat and vaporizes. The gaseous refrigerant is compressed into high-temperature and high-pressure superheated steam under the action of the compressor, and then enters the first condenser and the second condenser.

[0064] When the car needs to be heated, the high-temperature refrigerant exchanges heat with the heat exchange medium of the air conditioning system in the first condenser, releasing heat to heat the cabin; when the power battery is in a low-temperature state and needs to be heated, the refrigerant exchanges heat with the battery coolant in the second condenser to heat the battery. After the condensed refrigerant is depressurized by the throttling element, it exchanges heat with the heat of the dual electric drive axle again through the evaporator, and the cycle repeats.

[0065] This directional heat transfer not only improves the heat dissipation efficiency of the electric drive axle, but also reduces the energy consumption of the air conditioning system and power battery heating in the vehicle, improving the energy utilization efficiency of the entire vehicle. When the vehicle is in a cold environment, this collaborative heat management method has a significant energy-saving effect.

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

[0067] For example, when the air conditioning system in the car needs to be cooled and the power battery needs to be heated, after the refrigerant is compressed by the compressor, part of the high-temperature refrigerant enters the second condenser to heat the power battery, and the other part enters the first condenser (which serves as an evaporator at this time) to cool the car after throttling. 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 achieve waste heat recovery.

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

[0069] In one embodiment of the present invention, the function of the main control unit 140 is implemented by a vehicle controller (VCU). During the temperature control process of the dual electric drive axle, the VCU collects 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 conditions.

[0070] Specifically, 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 dual electric drive axle based on the collected signals and the preset flow-opening-oil temperature correlation model. Subsequently, the main control unit 140 sends corresponding control instructions to the water pump controller, three-way valve controller and dual electric drive axle controller respectively to achieve coordinated 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. According to the temperature requirements of the air conditioning system and the power battery in the vehicle, the heat pump unit 130 is scheduled to recover waste heat and distribute heat. Through the unified scheduling of the main control unit 140, the coordinated control of the vehicle thermal management system is realized, and the operating efficiency of the system is improved.

[0072] Furthermore, based on the above dual electric drive axle temperature control system 100, the embodiment of the present invention further discloses a dual electric drive axle temperature control method, the execution subject of the control method is the main control unit 140 in the above embodiment, and the technical features already included in the above embodiment are naturally inherited in the following control method embodiment, and will not be repeated one by one. Figure 3 , the control method at least includes steps S210 to S240.

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

[0074] In one embodiment of the present invention, temperature signals of the middle electric drive axle oil temperature sensor and the rear electric drive axle oil temperature sensor are collected to obtain real-time oil temperature data of the two electric drive axles. At the same time, temperature signals of the temperature sensors at the inlet and outlet of the heat exchange unit 124 are collected to monitor the temperature change before and after the coolant heat exchange. The main control unit 140 filters the collected temperature signals to eliminate the influence of signal noise and improve the accuracy of the temperature data.

[0075] During the acquisition process, the main control unit 140 will also judge the validity of the temperature signal. When an abnormal temperature sensor signal is detected (such as signal interruption, value out of range, etc.), the main control unit 140 can activate the backup strategy and estimate the temperature value at that location through the signals of other temperature sensors to ensure that the system can continue to operate reliably.

[0076] The collected temperature signal will be used as the input parameter of the subsequent control strategy to judge the working status of the dual electric drive axle and determine the corresponding control measures.

[0077] Step S220: Based on the temperature signal, determine whether the oil temperature of the dual electric drive axle is within a preset temperature range.

[0078] In one embodiment of the present invention, it is first determined whether the oil temperature of the central electric drive axle and the rear electric drive axle is within a preset temperature range, and the preset temperature range is preferably 80°C-90°C, which is the optimal operating temperature range of the electric drive axle. When the oil temperature is lower than 80°C, it is determined to be in a low temperature state, and the viscosity of the transmission oil is relatively large at this time, which will increase mechanical losses; when the oil temperature is higher than 90°C, it is determined to be in a high temperature state, which may affect the working reliability of the electric drive axle.

[0079] In one embodiment of the present invention, the temperature difference between the middle electric drive axle and the rear electric drive axle needs to be calculated. When the temperature difference exceeds a preset threshold (such as 10°C), it is determined that the dual electric drive axles are in a temperature imbalance state, and the torque distribution ratio needs to be adjusted to balance the temperature.

[0080] In one embodiment of the present invention, the main control unit 140 can also predict the temperature change trend of the dual electric drive axle based on the working condition information such as vehicle speed and torque demand, and provide a decision basis for the subsequent control strategy. For example, under continuous high torque conditions, even if the current oil temperature is within the normal range, corresponding temperature control measures need to be taken in advance.

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

[0082] In one embodiment of the present invention, when the oil temperature is lower than the first preset temperature, the vehicle may be in the starting stage, and the water pump unit 122 is controlled to reduce the target flow rate, 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 allow the coolant to be fully heated when passing through the motor, on the one hand, the water pump speed is reduced to reduce the coolant flow rate and extend the heat exchange time. On the other hand, the opening of the first outlet of the three-way valve is increased to ensure that more coolant passes through the heat exchange unit 124, thereby improving the heat exchange efficiency and accelerating the heating rate of the transmission oil.

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

[0084] In one embodiment of the present invention, 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 means that the coolant temperature is not enough to heat the transmission oil. At this time, the first outlet of the three-way valve is completely closed, so that the coolant circulates directly through the second outlet, avoiding the coolant taking away the heat of the electric drive axle, thereby achieving a rapid increase in the oil temperature.

[0085] In one embodiment of the present invention, when the oil temperature reaches the second preset temperature, the three-way valve unit 123 is controlled to increase the target opening 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 this temperature is reached, heat dissipation needs to be enhanced. At this time, the opening of the first outlet of the three-way valve is increased, and the water pump flow rate is increased at the same time to enhance the heat exchange cycle of the coolant; preferably, when adjusting the water pump unit 122 and the three-way valve unit 123, based on a preset flow-opening-oil temperature association model, the target flow rate and target opening are synchronously adjusted to achieve precise control of the oil temperature.

[0086] Furthermore, "controlling the three-way valve unit 123 to increase the target opening of the first outlet, and / or controlling the water pump unit 122 to increase the target flow rate" specifically means that only the opening of the first outlet of the three-way valve can be increased, or only the water pump flow rate can be increased, or both can be adjusted at the same time. The specific adjustment method is determined based on a preset flow-opening-oil temperature correlation model. For example, when the temperature is slightly higher than the target value, only one of the parameters may need to be adjusted. When the temperature significantly exceeds the target value, both parameters may need to be adjusted at the same time to enhance the heat dissipation effect.

[0087] In one embodiment of the present invention, the preset flow-opening-oil temperature association model is established based on the mapping relationship between the three parameters of prior oil temperature, target flow and three-way valve opening. In an optional embodiment, when the oil temperature is in the range of 85°C-90°C, it can be configured as follows:

[0088] When the oil temperature is 85℃, the opening of the first outlet of the three-way valve is 20%, and the water pump flow is 60% of the base flow;

[0089] When the oil temperature is 86℃, the opening of the first outlet of the three-way valve is 40%, and the water pump flow is 70% of the base flow;

[0090] When the oil temperature is 87℃, the opening of the first outlet of the three-way valve is 60%, and the water pump flow is 80% of the base flow;

[0091] When the oil temperature is 88℃, the opening of the first outlet of the three-way valve is 80%, and the water pump flow is 90% of the base flow;

[0092] When the oil temperature is 89℃, the opening of the first outlet of the three-way valve is 90%, and the water pump flow is 95% of the base flow;

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

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

[0095] Of course, the above values ​​are only preferred embodiments, and those skilled in the art can adjust the specific parameters according to the actual application scenario. By presetting the above association model, the coordinated control of the water pump flow and the three-way valve opening can be achieved during the temperature control process to improve the accuracy of temperature control, while avoiding real-time calculation during temperature control, thereby improving the timeliness of system response.

[0096] In one embodiment of the present invention, step S230 further includes:

[0097] When it is detected that the oil temperature difference of the dual electric drive axles 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 tend to balance.

[0098] Specifically, the main control unit 140 can calculate the oil temperature difference ΔT between the middle electric drive axle and the rear electric drive axle in real time, and when ΔT exceeds a preset threshold (e.g., 10°C), the torque redistribution strategy is initiated. 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 one embodiment of the present invention, when the oil temperature of the middle electric drive axle is higher than that of the rear electric drive axle, K'=K-α×ΔT; when the oil temperature of the rear electric drive axle is higher than that of the middle electric drive axle, K'=K+α×ΔT; wherein α is an adjustment coefficient, which can be determined according to actual calibration.

[0100] Preferably, in order to ensure the dynamic performance of the whole vehicle, when adjusting the torque distribution ratio, the change rate of torque adjustment shall not exceed 5% / s to avoid sudden changes affecting the driving experience; 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 will not affect the driving experience. It can ensure the temperature balance of the two electric drive axles (to prevent overheating of a single axle), while improving the dynamic performance and adaptability of working conditions.

[0101] In one embodiment of the present invention, step S230 further includes a protection control strategy for single bridge temperature exceeding a limit:

[0102] When it is detected that the oil temperature of an electric drive axle exceeds the maximum safety threshold (such as 95°C), the temperature protection strategy is triggered: first, the output torque of the electric drive axle is immediately reduced, and the torque limit coefficient decreases with the increase in temperature; at the same time, the load is transferred to the electric drive axle with normal temperature.

[0103] Specifically, for models 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 target output torque distribution ratio is adjusted to achieve temperature balance. When in a single-axle drive state or encountering a high load condition (such as climbing), if the single-axle oil temperature exceeds 95°C, the temperature protection strategy is triggered to limit the output torque of the electric drive axle.

[0104] For models with dual electric drive axles of different powers, the temperature balance strategy has a limited adjustment range due to the different rated powers of the two electric drive axles, and about 50% of the temperature control needs to be achieved by the temperature protection strategy. When the temperature of the high-power electric drive axle is high, if a large torque output is required at this time (such as climbing a hill), the system will use the temperature balance strategy and the temperature protection strategy in a coordinated manner: on the one hand, the torque output ratio of the low-power electric drive axle is increased, and on the other hand, the torque limit is implemented on the high-temperature electric drive axle.

[0105] Through the coordination of this dual-layer control strategy, it can not only meet the needs of different power configurations, but also effectively avoid overheating of a single bridge under high load conditions, ensuring reliable operation of the system while guaranteeing vehicle power performance.

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

[0107] In one embodiment of the present invention, the main control unit 140 analyzes the temperature data within the sampling period, calculates the rate of change and the trend of the temperature, and determines the current temperature change state based on the sliding average calculation of the historical temperature data, providing a basis for subsequent dynamic adjustment. In this embodiment, the specific value of the sampling period is no longer limited, and those skilled in the art can freely set it according to their needs.

[0108] In one embodiment of the present invention, when the temperature is on an upward trend, control measures of corresponding intensity 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 is on 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 are kept unchanged and trend monitoring continues.

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

[0110] like Figure 4 In one embodiment of the present invention, the dual electric drive bridge temperature control method further includes steps S310 to S330.

[0111] Step S310: Acquire the operating status signals of the in-vehicle air conditioning system and the power battery, and the temperature signal of the dual electric drive axle.

[0112] In one embodiment of the present invention, the working status signal of the in-vehicle air-conditioning system includes the working mode, target temperature, and current temperature of the air-conditioning system; the working status signal of the power battery includes status signals such as the temperature of the power battery and heating demand; the temperature signal of the dual electric drive axle includes the oil temperature and coolant temperature of the two electric drive axles.

[0113] Step S320: When the preset heat pump start-up conditions are met, the heat pump unit is started and controlled to transfer the heat of the dual electric drive axle to the in-vehicle air conditioning system or the power battery.

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

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

[0116] In one embodiment of the present invention, the principle for determining the priority of heat transfer is: when the power battery temperature is lower than the safe operating temperature, priority is given to heating the power battery; when there is a heating demand in the passenger compartment and the power battery temperature is within a safe range, priority is given to heating the interior of the vehicle; when the temperature of the dual electric drive axle is close to the upper limit, dual heat transfer can be performed simultaneously.

[0117] Through this priority-based heat transfer strategy, the rational distribution and efficient utilization of vehicle heat are achieved, improving the overall energy efficiency of the system.

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

[0119] When the vehicle is in urban road conditions, during the frequent starting and stopping and acceleration and deceleration process, the temperature of the dual electric drive axles gradually increases. When it is detected that the oil temperature reaches the second preset temperature, the main control unit 140 synchronously adjusts the three-way valve opening and the water pump flow based on the flow-opening-oil temperature association model to enhance heat dissipation. At the same time, due to the frequent starting and stopping of the vehicle under congested conditions, the temperature of the two electric drive axles may differ. At this time, the main control unit 140 adjusts the target output torque distribution ratio 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 are balanced. In addition, when the heat pump start-up conditions are met, the main control unit 140 controls the heat pump unit 130 to transfer the heat generated by the dual electric drive axles to the in-vehicle air-conditioning system to improve energy utilization efficiency.

[0120] When the vehicle is in highway conditions, the main control unit 140 continuously monitors the temperature signal of the dual electric drive axle. When the oil temperature reaches the second preset temperature, the target flow and target opening are dynamically adjusted based on the temperature change trend. At the same time, in order to improve the cruising range, the main control unit 140 optimizes the torque distribution strategy to reduce system energy consumption while ensuring temperature balance. When the ambient temperature is low, the main control unit 140 determines whether the heat pump start-up conditions are met, and if necessary, transfers the heat of the dual electric drive axle to the power battery to improve battery performance.

[0121] When the vehicle is in mountainous road conditions, due to frequent climbing and descending, the load of the dual electric drive axle changes greatly, resulting in significant fluctuations in oil temperature. The main control unit 140 monitors the temperature signal in real time. When it detects that the oil temperature of a certain electric drive axle is too high, it adjusts the target output torque distribution ratio and increases the flow of the water pump unit 122 to enhance heat dissipation. During the downhill process, when the heat pump start-up conditions are met, the main control unit 140 controls the heat pump unit 130 to transfer the heat of the dual electric drive axle to the in-vehicle air conditioning system to improve energy utilization efficiency.

[0122] When the vehicle is in cold weather conditions, when the vehicle is started, the temperatures of the dual electric drive axle and the power battery are low. At this time, the main control unit 140 controls the heat pump unit 130 to start, and transfers the ambient heat or heat from other heat sources to the dual 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 coolant and avoid overcooling. 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 changing trend of the temperature signal to ensure the reliable operation of the system in a low temperature environment.

[0123] In one embodiment of the present invention, a new energy commercial vehicle equipped with two electric drive axles is also provided. The vehicle is provided with the above-mentioned dual electric drive axle temperature control system 100 and can execute the above-mentioned dual electric drive axle temperature control method.

[0124] An embodiment of the present invention further provides an electronic device, which includes a memory and a processor, wherein a computer program executed by the processor is stored in the memory, and when the computer program is executed by the processor, the processor executes the dual electric drive bridge temperature control method described above. Various applications and various data may also be stored in the memory, such as various data used and / or generated by the application. The processor may 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 capabilities and / or instruction execution capabilities.

[0125] The embodiment of the present invention also provides a computer-readable storage medium, on which a computer program executed by a processor is stored. When the computer program is executed by the processor, the processor executes the dual electric drive axle temperature control method as described above. Exemplarily, the computer storage medium may include a memory card of a smart phone, a storage 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 portable compact disk read-only memory (CD-ROM), a USB memory, or any combination of the above storage media. The computer-readable storage medium may be any combination of one or more computer-readable storage media.

[0126] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present application to this. Those of ordinary skill in the art may make various changes and modifications therein without departing from the scope and spirit of the present application. All these changes and modifications are intended to be included within the scope of the present application as required by the appended claims.

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

[0128] Similarly, it should be understood that in order to streamline the present application and help understand one or more of the various inventive aspects, in the description of the exemplary embodiments of the present application, the various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, the method of the present application should not be interpreted as reflecting the following intention: the claimed application requires more features than the features clearly stated in each claim. More specifically, as reflected in the corresponding claims, the inventive point is that the corresponding technical problem can be solved with features less than all the features of a single disclosed embodiment. Therefore, the claims following the specific embodiment are hereby explicitly incorporated into the specific embodiment, wherein each claim itself serves as a separate embodiment of the present application.

[0129] It will be understood by those skilled in the art that, except for mutually exclusive features, all features disclosed in this specification (including the accompanying claims, abstracts and drawings) and all processes or units of any method or device disclosed in this specification may be combined in any combination. Unless otherwise expressly stated, each feature disclosed in this specification (including the accompanying claims, abstracts and drawings) may be replaced by an alternative feature that provides the same, equivalent or similar purpose.

[0130] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation modes, which are merely illustrative rather than restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are within the protection of the present invention.

Claims

1. A dual electric drive axle temperature control system, characterized in that: include: - a temperature collection unit, which is at least arranged in the dual electric drive axle and is used to detect the oil temperature of the dual electric drive axle respectively; - a thermal management circuit, comprising a coolant storage unit, a water pump unit, a three-way valve unit and a heat exchange unit, wherein the heat exchange unit is at least partially disposed on the dual electric drive axle, the water pump unit is disposed between the coolant storage unit and the three-way valve unit, the inlet of the three-way valve unit is communicated with the outlet of the water pump unit, the first outlet of the three-way valve unit is communicated with the heat exchange unit, and the second outlet of the three-way valve unit is communicated with the coolant storage unit circuit; - a heat pump unit, thermally connected to the heat exchange unit, for transferring the heat of the dual electric drive axle to the in-vehicle air conditioning system or the power battery under preset conditions; - A main control unit, which is electrically connected to the temperature acquisition unit, the water pump unit, the three-way valve unit and the heat pump unit, respectively, and is used to control 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 coolant entering the heat exchange unit, and / or control the output torque distribution ratio of the dual electric drive axle, and / or control the working state of the heat pump unit to maintain the oil temperature of the dual electric drive axle within a preset temperature range.

2. The dual electric drive axle temperature control system according to claim 1, characterized in that: The dual electric drive axle includes a motor, a gearbox and a motor controller; The heat exchange unit includes a first heat exchange unit, a second heat exchange unit and a third heat exchange unit which are connected 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.

3. The dual electric drive axle temperature control system according to claim 1, characterized in that: The thermal management circuit also includes a flow sensor, which is electrically connected to the main control unit and is used to detect the flow of the coolant.

4. The dual electric drive axle temperature control system according to claim 1, characterized in that: The heat pump unit comprises a refrigerant circuit and a plate heat exchanger; One side of the plate heat exchanger is thermally connected to the heat exchange unit, and the other side is connected to 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 thermally connected to the in-vehicle air conditioning system, the second condenser is thermally connected to the power battery, and the evaporator exchanges heat with the heat exchange unit through the plate heat exchanger.

5. A dual electric drive axle temperature control method using the system as claimed in any one of claims 1 to 4, characterized in that: include: Acquire the temperature signal of the temperature acquisition unit in real time; Based on the temperature signal, determining whether the oil temperature of the dual electric drive axle is within a preset temperature range; According to the judgment result, 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 electric drive axle; Monitor the temperature regulation control execution effect of the dual electric drive axle, and dynamically adjust the target flow, and / or 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.

6. The dual electric drive bridge temperature control method according to claim 5, characterized in that: The method further comprises: Acquiring operating status signals of the in-vehicle air conditioning system and the power battery, and the temperature signal of the dual electric drive axle; When a preset heat pump start-up condition is met, the heat pump unit is started, and the heat pump unit is controlled to transfer the heat of the dual electric drive axle to the in-vehicle air conditioning system or the power battery; The priority of the heat transfer object is determined based on the working state signal and the temperature signal, and the corresponding heat transfer control is performed.

7. The dual electric drive bridge temperature control method according to claim 5, characterized in that: The step of determining the target flow rate of the water pump unit, the target opening of the three-way valve unit, and the target output torque distribution ratio of the dual electric drive axle according to the judgment result includes: 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 of the first outlet; When the oil temperature reaches the first preset temperature, controlling the three-way valve unit to reduce the target opening of the first outlet until it is closed, and keeping the second outlet open; When the oil temperature reaches a second preset temperature, controlling the three-way valve unit to increase the target opening of the first outlet, and / or controlling the water pump unit to increase the target flow rate; The first preset temperature is lower than the second preset temperature.

8. The dual electric drive bridge temperature control method according to claim 7, characterized in that: The step of determining the target flow rate of the water pump unit, the target opening of the three-way valve unit, and the target output torque distribution ratio of the dual electric drive axle according to the judgment result includes: Based on a preset flow-opening-oil temperature correlation model, the target flow and the target opening are synchronously adjusted.

9. The dual electric drive bridge temperature control method according to claim 5, characterized in that: The step of determining the target flow rate of the water pump unit, the target opening of the three-way valve unit, and the target output torque distribution ratio of the dual electric drive axle according to the judgment result includes: When it is detected that the oil temperature difference of the dual electric drive axles 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 are balanced.

10. A vehicle, characterized in that: It comprises a dual electric drive axle temperature control system as described in any one of claims 1 to 4.

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