A mode switching method of a nine-way valve-based whole vehicle thermal management system of an electric vehicle

Abstract

This invention discloses a mode switching method for an electric vehicle thermal management system based on a nine-way valve. Mode matching is performed according to the operating conditions of the vehicle compartment, battery, and motor. After the mode is determined, if there is no change in the nine-way valve's position between the old and new modes, each actuator performs closed-loop follow-up adjustment. If there is, the system performs coordinated deceleration of the power source, reconstructs the valve body channel, and re-pressurizes the target circuit. During system startup, the physical hydraulic channels of the nine-way valve and the three-way valve are prioritized, followed by the water pump starting, and finally the electronic expansion valve initializes to a preset opening, with the compressor starting to build pressure. During system shutdown, the compressor and water pump first coordinately decelerate to zero, then the three-way valve and the nine-way valve sequentially perform reset or power-off position-preserving switching, and finally the electronic expansion valve closes. Furthermore, a graded early warning system is implemented for core components, and a graded utilization strategy is applied to the motor's waste heat. This invention has advantages such as high energy utilization efficiency, fast system response speed, and good long-term reliability.

Description

Technical Field

[0001] This invention relates to a mode switching method for an electric vehicle thermal management system, specifically to a mode switching method for an electric vehicle thermal management system based on a nine-way valve. Background Technology

[0002] With the increasing popularity of electric vehicles, the importance of the vehicle thermal management system is becoming increasingly prominent. It not only needs to ensure that core components such as batteries, motors, and electronic controls operate within suitable temperature ranges, but also needs to consider the comfort needs of the passenger compartment, and its energy efficiency directly affects the vehicle's driving range. However, existing electric vehicle thermal management systems mostly adopt a centralized control architecture. Their operating condition mode recognition usually relies on simple single threshold judgments, lacking a comprehensive evaluation of multi-source signals such as ambient temperature, battery temperature, motor temperature, and passenger compartment requirements, which easily leads to mode misjudgment or frequent mode switching. Regarding mode switching control, existing strategies typically use a preset switching matrix, that is, exhaustively enumerating the switching paths between any two modes and pre-setting the actuator action sequence for each combination. This "mode-to-mode" hard mapping method causes the switching combinations to expand exponentially with the number of modes, making development and calibration extremely cumbersome, and any change in hardware configuration will trigger a complete rework of the control software. More importantly, existing vehicle thermal management systems generally lack a unified timing coordination mechanism during mode switching. Actuator commands are often issued in parallel or simply sequentially, without optimization of the action sequence, time intervals, and adjustment rates. This easily leads to hydraulic shock in the coolant circuit and drastic pressure fluctuations in the refrigerant circuit, thus affecting system stability and component lifespan. Furthermore, existing technologies often employ crude on / off control for motor waste heat recovery, resulting in the heat pump still needing high power to absorb heat from the outside under low-temperature conditions, leading to high overall vehicle energy consumption. There is also a lack of systematic safety protection and fault-tolerance mechanisms for abnormal conditions such as compressor overpressure, valve jamming, and water pump idling. The overall reliability and energy efficiency of the system still have significant room for improvement. Summary of the Invention

[0003] Purpose of the invention: The purpose of this invention is to provide a mode switching method for an electric vehicle thermal management system based on a nine-way valve that can avoid mode misjudgment and improve mode switching response speed, energy utilization efficiency and long-term reliability.

[0004] Technical solution: The present invention provides a mode switching method for an electric vehicle thermal management system based on a nine-way valve. The electric vehicle thermal management system includes a motor control main circuit, a motor control auxiliary circuit, a battery circuit, a passenger compartment circuit, a cold air core circuit, a low-temperature coolant circuit, a warm air core circuit, a high-temperature coolant circuit, a heat pump circulation circuit, a cold-side three-way valve, a hot-side three-way valve, and a nine-way valve.

[0005] The main circuit of the motor control system is connected to ports 1 and 3 of the nine-way valve, respectively. The auxiliary circuit of the motor control system is connected to ports 2 and 3 of the nine-way valve, respectively. The battery circuit is connected to ports 4 and 5 of the nine-way valve, respectively. The battery circuit includes a third water pump. The cold air core circuit is thermally coupled to the heat pump circulation circuit through the evaporator. The inlet and first outlet of the cold-side three-way valve are connected to the cold air core circuit. Simultaneously, the cold air core circuit is thermally coupled to the passenger compartment circuit through the cold air core. The cold air core circuit includes a first water pump and a PTC. The low-temperature coolant circuit is formed by adding a parallel cold air core pipeline to the cold air core circuit. This parallel cold air core pipeline includes a connection to port 9 of the nine-way valve. The system includes a pipeline connecting the second outlet of the cold-side three-way valve and a pipeline connecting port 8 of the nine-way valve to the outlet of the cold air core coolant. The warm air core circuit is thermally coupled to the heat pump circulation circuit via a condenser. The inlet and first outlet of the hot-side three-way valve are connected to the warm air core circuit, and the warm air core circuit is thermally coupled to the passenger compartment circuit via the warm air core. The warm air core circuit has a second water pump. The high-temperature coolant circuit is formed by adding a parallel pipeline to the warm air core circuit. This parallel pipeline includes a pipeline connecting port 7 of the nine-way valve and the second outlet of the hot-side three-way valve, and a pipeline connecting port 6 of the nine-way valve and the outlet of the warm air core coolant. The heat pump circulation circuit has a compressor and an electronic expansion valve.

[0006] By controlling the connection mode of the cold-side three-way valve, the hot-side three-way valve, and the nine-way valve, and configuring the heat pump circulation loop to work or not work, the main circuit of motor control, the auxiliary circuit of motor control, the battery circuit, the cold air core circuit, the low-temperature coolant circuit, the warm air core circuit, and the high-temperature coolant circuit can form different circuits, so as to realize that the electric vehicle thermal management system works in different operating modes.

[0007] The mode switching method is implemented based on a hierarchical collaborative control architecture of the decision-making layer and the execution layer, including:

[0008] S1: Signal Acquisition: The decision-making layer receives and integrates multi-dimensional signals from the entire vehicle, including driving status, cabin environment, human-machine interaction commands, battery and motor temperatures;

[0009] S2: Operating Condition Identification and Mode Determination: The decision-making layer identifies the current state of the vehicle compartment, battery, and motor, and then matches and maps one of the several preset operating modes of the vehicle based on the target operating condition combination of the three.

[0010] S3: Command Issuance and Mapping: The decision-making layer issues the target operating mode command to the execution layer, and the execution layer performs closed-loop control on each actuator of the electric vehicle thermal management system.

[0011] S4: Smooth timing switching: The action execution of the thermal management system is divided into dynamic mode switching logic and system start-up and shutdown logic. After receiving the mode switching signal, anti-jitter judgment is performed, and the state of each actuator is adjusted according to the predetermined dynamic timing. The hydraulic shock and pressure fluctuation are eliminated by using the "speed reduction and position preservation" and "step-by-step asynchronous response" mechanisms.

[0012] S5: Safety graded protection: The execution layer monitors the operating parameters of core components in real time, performs full-process safety protection of "graded early warning + fault shutdown", and links the decision layer to switch to safety mode when a serious fault is triggered; core components include compressor, valve body and water pump.

[0013] Further, in step S2, the cabin operating conditions include cabin cooling, cabin heating, and no-demand conditions; the entry condition for cabin cooling is cabin temperature ≥ cabin set temperature, and the exit condition is user manually turning off the air conditioner or cabin set temperature ≥ outdoor ambient temperature; the entry condition for cabin heating is cabin temperature ≤ cabin set temperature, and the exit condition is user manually turning off the air conditioner or cabin set temperature ≤ outdoor ambient temperature; the entry condition for no-demand conditions is user manually turning off the air conditioner, and the exit condition is meeting the entry conditions for cabin cooling or cabin heating.

[0014] Further, in step S2, the battery operating conditions include battery cooling, battery heating, and self-circulation. The entry condition for battery cooling is that the highest temperature of the battery pack is ≥ the upper limit of the battery pack's safety temperature, and the exit condition is that |the temperature difference between the inlet and outlet of the battery pack liquid| < the battery cooling exit value and the lowest temperature of the battery pack is ≤ the lower limit of the battery pack's safety temperature. The entry condition for battery heating is that the lowest temperature of the battery pack is ≤ the lower limit of the battery pack's safety temperature, and the exit condition is that |the temperature difference between the inlet and outlet of the battery pack liquid| > the battery heating exit value and the highest temperature of the battery pack is ≥ the upper limit of the battery pack's safety temperature. The entry condition for self-circulation is that the highest temperature of the battery pack is ≤ the upper limit of the battery pack's safety temperature or the lowest temperature of the battery pack is ≥ the lower limit of the battery pack's safety temperature, and the exit condition is that the highest temperature of the battery pack is ≥ the upper limit of the battery pack's safety temperature or the lowest temperature of the battery pack is ≤ the lower limit of the battery pack's safety temperature.

[0015] Furthermore, in step S2, the motor operating conditions include sufficient motor residual heat and insufficient motor residual heat. Different motor temperature thresholds are determined according to the vehicle speed, and then the motor temperature is used for judgment. When the motor temperature is greater than the motor temperature threshold, the motor residual heat is sufficient; otherwise, the motor residual heat is insufficient.

[0016] Further, in step S4, the dynamic mode switching logic is as follows: During the operation of the vehicle, when the decision layer issues a mode switching command, the execution layer first performs a set time anti-shake delay judgment to filter signal transient jumps; after confirming a valid switch, the execution layer performs conditional branch judgment: if the switch between the old and new modes does not involve a change in the position of the nine-way valve, then each actuator directly performs closed-loop follow adjustment; if the switching process involves a change in the position of the nine-way valve, then the set timing control chain is activated to avoid drastic hydraulic and pressure fluctuations.

[0017] Furthermore, the established timing control chain includes:

[0018] 1) Power source coordinated deceleration: When it is confirmed that the nine-way valve needs to be reversed, the compressor is first controlled to actively reduce speed, and then the water pumps in each circuit are linked to synchronously reduce speed;

[0019] 2) Valve body channel reconfiguration: After the power source decelerates, the nine-way valve is first driven to perform the work position switching; after the nine-way valve is accurately positioned and locked, the cold / hot side three-way valve is then switched to the target opening degree;

[0020] 3) Target circuit re-pressure: After the valve body channel is reconstructed, activate the water pump control, compressor control and electronic expansion valve control in sequence as needed.

[0021] Further, in step S4, the system start-stop logic is as follows: When the system receives a start command, it first establishes the physical liquid circuit channels of the nine-way valve and the three-way valve; then the water pump starts to establish a stable coolant circulation flow; finally, the electronic expansion valve initializes according to the preset opening degree, and the compressor starts to build pressure to ensure the safety of the refrigerant circuit; when the system receives a shut-off command, the compressor and water pump first work together to reduce speed to zero, cut off the power source and eliminate the dynamic pressure difference; then the three-way valve and the nine-way valve sequentially perform reset or power-off position-keeping switching; finally, the electronic expansion valve is closed to achieve dynamic locking and safe pressure release of the refrigerant circuit.

[0022] Furthermore, in step S5, the compressor safety protection includes: exhaust temperature protection, high pressure protection, and low pressure protection, which are executed according to the warning stage and the shutdown stage;

[0023] The exhaust temperature protection determines the warning stage and the shutdown stage based on the compressor exhaust temperature and different exhaust temperature thresholds. During the warning stage, a speed reduction action is performed. During the shutdown stage, the compressor enable is immediately cut off and a fault signal is fed back. The recovery condition is that the compressor exhaust temperature drops below the recovery temperature threshold and stabilizes for a first specified time.

[0024] The high-pressure protection determines the warning stage and the shutdown stage based on the compressor pressure and different high-pressure thresholds. During the warning stage, a speed reduction action is performed. During the shutdown stage, the compressor enable is immediately cut off, the electronic expansion valve is activated, and a fault signal is fed back. The recovery condition is that the compressor pressure drops below the first recovery pressure threshold and stabilizes for a second specified time.

[0025] The low-pressure protection determines the warning stage and the shutdown stage based on the compressor pressure and different low-pressure thresholds. During the warning stage, it performs a speed reduction action or reduces the speed and activates the corresponding valves. During the shutdown stage, it immediately cuts off the compressor enable or immediately cuts off the compressor enable and activates the corresponding valves, while feeding back a fault signal. The recovery condition is that the compressor pressure rises above the second recovery pressure threshold and stabilizes for a third specified time.

[0026] Furthermore, in step S5, valve body and water pump fault protection: if the valve core of the nine-way valve is stuck for more than 10% for 500ms, if the opening of the three-way valve is not adjusted within 1s, or if the speed / flow rate of the water pump does not reach the threshold after 300ms of starting, the system will shut down or reduce to a safe opening according to the preset strategy.

[0027] Furthermore, in step S5, when any actuator triggers a fault shutdown, the execution layer immediately cuts off the enable signal of the actuator and feeds back the fault signal to the decision layer; after receiving the fault signal, the decision layer switches to the safety mode, shuts down the heat pump circulation loop, and retains only the necessary cooling / heating loop to ensure the safe operation of the battery and motor.

[0028] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0029] In terms of pattern recognition, a multi-parameter fusion judgment strategy is adopted, and anti-jitter delay and hysteresis intervals are set to effectively avoid pattern misjudgment and frequent jumps. Regarding mode switching, this invention proposes a unified timing control method that does not rely on a jump matrix: regardless of which mode is switched from, the same underlying timing rules are followed—sequentially passing through stages such as refrigeration cycle response, valve switching, and pump speed regulation, with fixed delays inserted between each stage and a speed reduction and position-maintaining strategy. This design fundamentally avoids the tedious work of pre-setting a jump matrix, significantly reducing development complexity and calibration costs; simultaneously, due to the uniformity of the jump timing, mode switching response is faster, logic is clearer, and hydraulic shock and refrigerant pressure fluctuations are completely eliminated. Furthermore, this invention also reduces energy consumption in low-temperature conditions through a staged utilization strategy of motor waste heat, and significantly improves the system's operational reliability through full-process strategies such as compressor staged safety protection, valve failure protection, and water pump flow protection.

[0030] In summary, this invention has achieved significant beneficial effects in terms of temperature control accuracy, energy utilization efficiency, system response speed, and long-term reliability. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of the electric vehicle thermal management system based on a nine-way valve in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of six different connection methods of the nine-way valve in an embodiment of the present invention, wherein (a) is connection method one, (b) is connection method two, (c) is connection method three, (d) is connection method four, (e) is connection method five, and (f) is connection method six;

[0033] Figure 3 This is a schematic diagram of the signal interaction of the hierarchical collaborative control architecture in an embodiment of the present invention;

[0034] Figure 4 This is a timing diagram of mode switching involving the position switching of the nine-way valve in an embodiment of the present invention;

[0035] Figure 5 This is a safety timing diagram for the start and stop of each actuator in an embodiment of the present invention. Detailed Implementation

[0036] The invention will now be further described with reference to the accompanying drawings.

[0037] Appendix Figures 1 to 5 The accompanying figure labels are as follows:

[0038] 112, Compressor; 113, Condenser; 114, Electronic Expansion Valve; 115, Evaporator; 116, Vapor-Liquid Separator; 117, PTC (Electric Heating Water Jacket); 118, First Water Pump; 119, Cold Air Core; 120, Cold Side Three-Way Valve; 121, Hot Side Three-Way Valve; 122, Warm Air Core; 123, Second Water Pump; 124, Nine-Way Valve; 125, Radiator Fan; 126, Radiator; 127, Motor and Electronic Control Assembly; 128, Third Water Pump; 129, Battery Pack Liquid Cooling Assembly; 130, Passenger Compartment.

[0039] This invention provides a mode switching method for an electric vehicle thermal management system based on a nine-way valve, such as... Figure 1 As shown, the electric vehicle thermal management system based on the nine-way valve includes a motor control main circuit, a motor control auxiliary circuit, a battery circuit, a passenger compartment circuit, a cold air core circuit, a low-temperature coolant circuit, a warm air core circuit, a high-temperature coolant circuit, a heat pump circulation circuit, a cold-side three-way valve 120, a hot-side three-way valve 121, and a nine-way valve 124.

[0040] like Figure 2As shown, the nine-way valve 124 has six different connection modes:

[0041] Connection method 1: Connect ports 1 and 7 of the nine-way valve, ports 3 and 6 of the nine-way valve, ports 4 and 9 of the nine-way valve, and ports 5 and 8 of the nine-way valve; close the remaining ports.

[0042] Connection method 2: Connect ports 1 and 9 of the nine-way valve, ports 3 and 8 of the nine-way valve, ports 4 and 7 of the nine-way valve, ports 5 and 6 of the nine-way valve, and close the remaining ports.

[0043] Connection method 3: Connect ports 2 and 9 of the nine-way valve, connect ports 3 and 8 of the nine-way valve, connect ports 4 and 7 of the nine-way valve, connect ports 5 and 6 of the nine-way valve, and close the remaining ports.

[0044] Connection method four: Connect ports 1 and 7 of the nine-way valve, connect ports 3 and 6 of the nine-way valve, connect ports 4 and 5 of the nine-way valve, and close the remaining ports.

[0045] Connection method 5: Connect ports 1 and 9 of the nine-way valve, connect ports 3 and 8 of the nine-way valve, connect ports 4 and 5 of the nine-way valve, and close the remaining ports.

[0046] Connection method six: Connect port 2 and port 9 of the nine-way valve, connect port 3 and port 8 of the nine-way valve, connect port 4 and port 5 of the nine-way valve, and close the other ports.

[0047] The two ends of the motor control main circuit are connected to port 1 and port 3 of the nine-way valve, respectively, for the coolant to exchange heat with the outdoor environment and the motor control assembly 127 in sequence.

[0048] The two ends of the motor control auxiliary circuit are connected to port 2 and port 3 of the nine-way valve, respectively, for heat exchange between the coolant and the motor control assembly 127.

[0049] The two ends of the battery circuit are connected to ports 4 and 5 of the nine-way valve, respectively, for heat exchange between the coolant and the battery pack liquid cooling assembly 129, so as to achieve temperature control or battery temperature equalization.

[0050] The crew compartment circuit has a cold air core 119 and a warm air core 122. The cold air core 119 is used for heat exchange between the air and the low-temperature coolant in the cold air core circuit to provide low-temperature air for the crew compartment 130. The warm air core 122 is used for heat exchange between the air and the high-temperature coolant in the warm air core circuit to provide high-temperature air for the crew compartment 130.

[0051] The coolant in the cold air core circuit exchanges heat with the refrigerant in the heat pump circulation circuit through the evaporator 115 to form a low-temperature coolant. At the same time, the inlet end and the first outlet end of the cold side three-way valve 120 are connected to the cold air core circuit.

[0052] The cryogenic coolant circuit is formed by adding a parallel cooling air core pipeline to the existing cooling air core circuit. This parallel cooling air core pipeline includes a pipeline connecting port 9 of the nine-way valve and the second outlet of the cold-side three-way valve 120, and a pipeline connecting port 8 of the nine-way valve and the coolant outlet of the cooling air core 119. The cold-side three-way valve 120 can distribute the cryogenic coolant to the cooling air core 119, port 9 of the nine-way valve, or simultaneously to both port 9 of the nine-way valve and the cooling air core 119. By switching the connection mode of the nine-way valve 124, the cryogenic coolant can be delivered to the battery circuit, the main circuit of the motor control system, or the auxiliary circuit of the motor control system via port 9 of the nine-way valve.

[0053] The coolant in the heating core circuit exchanges heat with the refrigerant in the heat pump circulation circuit through the condenser 113 to form a high-temperature coolant. At the same time, the inlet end and the first outlet end of the hot-side three-way valve 121 are connected to the heating core circuit.

[0054] The high-temperature coolant circuit is formed by adding a parallel heating core pipeline to the existing heating core circuit. This parallel heating core pipeline includes a pipeline connecting port 7 of the nine-way valve and the second outlet of the hot-side three-way valve 121, and a pipeline connecting port 6 of the nine-way valve and the coolant outlet of the heating core 122. The hot-side three-way valve 121 can distribute the high-temperature coolant to the heating core 122, port 7 of the nine-way valve, or both. By switching the connection mode of the nine-way valve 124, the high-temperature coolant can be delivered to the battery circuit, the main motor control circuit, or the auxiliary motor control circuit via port 7 of the nine-way valve.

[0055] The following is a detailed explanation of the structure of each circuit.

[0056] The main circuit for motor control is a loop consisting of the sequential connection of port 1 of the nine-way valve, radiator 126, motor control assembly 127, and port 3 of the nine-way valve. Radiator 126 is equipped with a radiator fan 125. In this main circuit, the coolant passes sequentially through port 1 of the nine-way valve, radiator 126, motor control assembly 127, and port 3 of the nine-way valve.

[0057] The motor control auxiliary circuit is a circuit consisting of the sequential connection of port 2 of the nine-way valve, the motor control assembly 127, and port 3 of the nine-way valve. In this motor control auxiliary circuit, the coolant passes sequentially through port 2 of the nine-way valve, the motor control assembly 127, and port 3 of the nine-way valve.

[0058] The battery circuit is a loop consisting of the 4th port of the nine-way valve, the third water pump 128, the battery pack liquid cooling assembly 129, and the 5th port of the nine-way valve connected in sequence. In this battery circuit, the coolant passes through the 4th port of the nine-way valve, the third water pump 128, the battery pack liquid cooling assembly 129, and the 5th port of the nine-way valve in sequence.

[0059] The crew compartment circuit uses the HVAC assembly in the crew compartment 130 to drive the air circulation flow, and the air passes through the cold air core 119, the warm air core 122, and the crew compartment 130 in sequence.

[0060] The cold air core circuit is a circuit consisting of the cold air core 119, the first water pump 118, the PTC 117, the evaporator 115, and the cold-side three-way valve 120 connected in sequence. The coolant passes through the first water pump 118, the PTC 117, the evaporator 115, and the cold-side three-way valve 120 in sequence before reaching the cold air core 119.

[0061] The low-temperature coolant circuit is formed by adding a parallel pipeline of the cold air core to the cold air core circuit, which will not be elaborated here.

[0062] The heating core circuit is a circuit consisting of the heating core 122, the second water pump 123, the condenser 113, and the hot-side three-way valve 121 connected in sequence. The coolant passes through the second water pump 123, the condenser 113, and the hot-side three-way valve 121 in sequence before reaching the heating core 122.

[0063] The high-temperature coolant circuit is formed by adding a parallel pipeline of the warm air core to the warm air core circuit, which will not be elaborated here.

[0064] The heat pump cycle loop is a loop consisting of compressor 112, condenser 113, electronic expansion valve 114, evaporator 115, and vapor-liquid separator 116 connected in sequence, using R290 as the refrigerant. The refrigerant is compressed and pressurized by compressor 112 into a high-temperature, high-pressure superheated gas, then condenses in condenser 113, releasing heat to the cooling liquid and becoming a high-pressure subcooled liquid. It then expands in electronic expansion valve 114 into a low-temperature, low-pressure subcooled liquid, and finally absorbs heat from the cooling liquid in evaporator 115 to become a low-temperature, low-pressure gas. Finally, it is drawn back into compressor 112 through vapor-liquid separator 116. This heat pump cycle loop is existing technology.

[0065] By controlling the connection mode of the cold-side three-way valve 120, the hot-side three-way valve 121, and the nine-way valve 124, and configuring the heat pump circulation loop to work or not work, the electric vehicle thermal management system can achieve up to 14 different operating modes. The following is a detailed explanation of these 14 different operating modes.

[0066] Operating mode 1: Single battery cooling mode, the nine-way valve 124 adopts connection method 1, the cold side three-way valve 120 connects to the low temperature coolant circuit, the hot side three-way valve 121 connects to the high temperature coolant circuit, and the heat pump circulation circuit is configured to work.

[0067] The low-temperature side coolant circulates sequentially through the first water pump 118, PTC 117, the coolant side of the evaporator 115, the cold-side three-way valve 120, port 9 of the nine-way valve, port 4 of the nine-way valve, the third water pump 128, the battery pack liquid cooling assembly 129, port 5 of the nine-way valve, port 8 of the nine-way valve, and the first water pump 118. The low-temperature side coolant releases heat and cools down in the evaporator 115, and absorbs heat and heats up in the battery pack liquid cooling assembly 129.

[0068] The high-temperature side coolant circulates sequentially through the second water pump 123, the coolant side of the condenser 113, the hot-side three-way valve 121, port 7 of the nine-way valve, port 1 of the nine-way valve, the radiator 126, the motor and electronic control assembly 127, port 3 of the nine-way valve, port 6 of the nine-way valve, and finally back to the second water pump 123. The high-temperature side coolant absorbs heat and heats up in the condenser 113, dissipates heat and cools down in the radiator 126, and then absorbs heat again and heats up through the motor and electronic control assembly 127.

[0069] Operating mode 2: Single battery heating mode, the nine-way valve 124 adopts connection method 2, the cold side three-way valve 120 connects to the low temperature coolant circuit, the hot side three-way valve 121 connects to the high temperature coolant circuit, and the heat pump circulation circuit is configured to work.

[0070] The low-temperature side coolant circulates sequentially through the first water pump 118, PTC 117, the coolant side of the evaporator 115, the cold-side three-way valve 120, port 9 of the nine-way valve, port 1 of the nine-way valve, the radiator 126, the motor and electronic control assembly 127, port 3 of the nine-way valve, port 8 of the nine-way valve, and the first water pump 118. The low-temperature side coolant releases heat and cools down in the evaporator 115, and absorbs heat and warms up in the radiator 126 and the motor and electronic control assembly 127.

[0071] The high-temperature side coolant circulates sequentially through the second water pump 123, the coolant side of the condenser 113, the hot-side three-way valve 121, port 7 of the nine-way valve, port 4 of the nine-way valve, the third water pump 128, the battery pack liquid cooling assembly 129, port 5 of the nine-way valve, port 6 of the nine-way valve, and finally back to the second water pump 123. The high-temperature side coolant absorbs heat and heats up in the condenser 113, and dissipates heat and cools down in the battery pack liquid cooling assembly 129.

[0072] Operating mode 3: Single battery heating - using only motor waste heat mode, the nine-way valve 124 adopts connection mode 3, the cold side three-way valve 120 connects to the low temperature coolant circuit, the hot side three-way valve 121 connects to the high temperature coolant circuit, and the heat pump circulation circuit is configured to work.

[0073] The low-temperature side coolant circulates sequentially through the first water pump 118, PTC 117, the coolant side of the evaporator 115, the cold-side three-way valve 120, port 9 of the nine-way valve, port 2 of the nine-way valve, the motor and electronic control assembly 127, port 3 of the nine-way valve, port 8 of the nine-way valve, and the first water pump 118. The low-temperature side coolant releases heat and cools down in the evaporator 115, and absorbs heat and heats up in the motor and electronic control assembly 127.

[0074] The high-temperature side coolant circulates sequentially through the second water pump 123, the coolant side of the condenser 113, the hot-side three-way valve 121, port 7 of the nine-way valve, port 4 of the nine-way valve, the third water pump 128, the battery pack liquid cooling assembly 129, port 5 of the nine-way valve, port 6 of the nine-way valve, and finally back to the second water pump 123. The high-temperature side coolant absorbs heat and heats up in the condenser 113, and dissipates heat and cools down in the battery pack liquid cooling assembly 129.

[0075] Operating mode four: Single crew cabin cooling mode, nine-way valve 124 adopts connection method four, cold side three-way valve 120 connects to the cold air core circuit, hot side three-way valve 121 connects to the high temperature coolant circuit, and the heat pump circulation circuit is configured to work.

[0076] The low-temperature side coolant circulates sequentially through the first water pump 118, PTC 117, the coolant side of the evaporator 115, the cold-side three-way valve 120, the cold air core 119, and back to the first water pump 118. The low-temperature side coolant releases heat and cools down in the evaporator 115, and absorbs heat and warms up in the cold air core 119. Air blowed by the HVAC assembly fan in the passenger compartment 130 is cooled by heat exchange in the cold air core 119 and then delivered into the passenger compartment 130. The HVAC assembly refers to the automotive heating, ventilation, and air conditioning system, which includes a fan used to drive airflow.

[0077] The high-temperature side coolant circulates sequentially through the second water pump 123, the coolant side of the condenser 113, the hot-side three-way valve 121, port 7 of the nine-way valve, port 1 of the nine-way valve, the radiator 126, the motor and electronic control assembly 127, port 3 of the nine-way valve, port 6 of the nine-way valve, and finally back to the second water pump 123. The high-temperature side coolant absorbs heat and heats up in the condenser 113, dissipates heat and cools down in the radiator 126, and then absorbs heat again and heats up through the motor and electronic control assembly 127.

[0078] In the battery circuit, the coolant passes through port 4 of the nine-way valve, the third water pump 128, the battery pack liquid cooling assembly 129, and port 5 of the nine-way valve for internal self-circulation and temperature equalization.

[0079] Operating mode 5: Single crew cabin heating mode, nine-way valve 124 adopts connection method 5, cold side three-way valve 120 connects to the low temperature coolant circuit, hot side three-way valve 121 connects to the heating core circuit, and the heat pump circulation circuit is configured to work.

[0080] The low-temperature side coolant circulates sequentially through the first water pump 118, PTC 117, the coolant side of the evaporator 115, the cold-side three-way valve 120, port 9 of the nine-way valve, port 1 of the nine-way valve, the radiator 126, the motor and electronic control assembly 127, port 3 of the nine-way valve, port 8 of the nine-way valve, and the first water pump 118. The low-temperature side coolant releases heat and cools down in the evaporator 115, and absorbs heat and heats up in the radiator 126 and the motor and electronic control assembly 127.

[0081] The high-temperature side coolant circulates sequentially through the second water pump 123, the coolant side of the condenser 113, the hot-side three-way valve 121, the heater core 122, and back to the second water pump 123. The high-temperature side coolant absorbs heat and heats up in the condenser 113, then releases heat to the air and cools down in the heater core 122. The HVAC assembly fan blows air that, after heat exchange in the heater core 122, is heated to hot air and then delivered into the passenger compartment 130.

[0082] In the battery circuit, the coolant passes through port 4 of the nine-way valve, the third water pump 128, the battery pack liquid cooling assembly 129, and port 5 of the nine-way valve for internal self-circulation and temperature equalization.

[0083] Operating Mode 6: Single Passenger Cabin Heating - Utilizing only the waste heat of the motor. The nine-way valve 124 is connected in mode 6. The cold-side three-way valve 120 is connected to the low-temperature coolant circuit, and the hot-side three-way valve 121 is connected to the heating core circuit. The heat pump circulation circuit is configured to operate.

[0084] The low-temperature side coolant circulates sequentially through the first water pump 118, PTC 117, the coolant side of the evaporator 115, the cold-side three-way valve 120, port 9 of the nine-way valve, port 2 of the nine-way valve, the motor and electronic control assembly 127, port 3 of the nine-way valve, port 8 of the nine-way valve, and the first water pump 118. During this circulation process, the low-temperature side coolant releases heat and cools down in the evaporator 115, and absorbs heat and heats up in the motor and electronic control assembly 127.

[0085] The high-temperature side coolant circulates sequentially through the second water pump 123, the coolant side of the condenser 113, the hot-side three-way valve 121, the heater core 122, and the second water pump 123. The high-temperature side coolant absorbs heat and heats up in the condenser 113, then releases heat to the air and cools down in the heater core 122. The air blower in the HVAC assembly inside the passenger compartment 130 is heated to high temperature after heat exchange in the heater core 122 before being sent into the passenger compartment 130.

[0086] In the battery circuit, the coolant passes through port 4 of the nine-way valve, the third water pump 128, the battery pack liquid cooling assembly 129, and port 5 of the nine-way valve for internal self-circulation and temperature equalization.

[0087] Operating mode seven: Dual cooling mode, the nine-way valve 124 adopts connection method one, the cold side three-way valve 120 simultaneously connects the cold air core circuit and the low temperature coolant circuit, the hot side three-way valve 121 connects the high temperature coolant circuit, and the heat pump circulation circuit is configured to work.

[0088] In dual-cooling mode, the low-temperature side coolant has two routes. The main route passes through the first water pump 118, PTC 117, and the coolant side of the evaporator 115, and splits into two branches at the cold-side three-way valve 120. Branch 1 is the vehicle compartment cooling route, and branch 2 is the battery cooling route. The flow of the two branches can be distributed through the cold-side three-way valve 120. In branch 1, the low-temperature side coolant enters the air cooling core 119, absorbs heat from the air, and then flows back to the main route. In branch 2, the low-temperature side coolant passes through port 9 and port 4 of the nine-way valve, the third water pump 128, the battery pack liquid cooling assembly 129, port 5 of the nine-way valve, and port 8 of the nine-way valve before flowing back to the main route.

[0089] The high-temperature side coolant circulates sequentially through the second water pump 123, the coolant side of the condenser 113, the hot-side three-way valve 121, port 7 of the nine-way valve, port 1 of the nine-way valve, the radiator 126, the motor and electronic control assembly 127, port 3 of the nine-way valve, port 6 of the nine-way valve, and finally back to the second water pump 123. The high-temperature side coolant absorbs heat and heats up in the condenser 113, dissipates heat and cools down in the radiator 126, and then absorbs heat again and heats up through the motor and electronic control assembly 127.

[0090] Operating mode 8: Dual heating mode. The nine-way valve 124 adopts connection method 2. The cold side three-way valve 120 connects to the low-temperature coolant circuit, and the hot side three-way valve 121 connects to both the heating core circuit and the high-temperature coolant circuit. The heat pump circulation circuit is configured to work.

[0091] In dual heating mode, the high-temperature side coolant has two routes. The main route passes through the second water pump 123 and the coolant side of the condenser 113, and then splits into two branches at the hot-side three-way valve 121. Branch 1 is the vehicle compartment heating route, and branch 2 is the battery heating route. The flow of the two branches can be distributed through the hot-side three-way valve 121. In branch 1, the high-temperature side coolant enters the heater core 122, releases heat to the air, and then flows back to the main route. In branch 2, the high-temperature side coolant passes through port 7 and port 4 of the nine-way valve, the third water pump 128, the battery pack liquid cooling assembly 129, port 5 of the nine-way valve, and port 6 of the nine-way valve before flowing back to the main route.

[0092] The low-temperature side coolant passes through the first water pump 118, PTC 117, the coolant side of evaporator 115, cold-side three-way valve 120, port 9 of nine-way valve, port 1 of nine-way valve, radiator 126, motor and electronic control assembly 127, port 3 of nine-way valve, port 8 of nine-way valve, and the first water pump 118. The low-temperature side coolant releases heat and cools down in evaporator 115, absorbs heat and heats up in radiator 126, and absorbs heat again and heats up through motor and electronic control assembly 127.

[0093] Operating Mode 9: Dual Heating - Utilizing only motor waste heat mode. The nine-way valve 124 adopts connection method three. The cold-side three-way valve 120 connects to the low-temperature coolant circuit, and the hot-side three-way valve 121 simultaneously connects to the heating core circuit and the high-temperature coolant circuit. The heat pump circulation circuit is configured to operate.

[0094] In the dual heating mode—utilizing only the motor's waste heat—the high-temperature side coolant has two routes. The main route passes through the second water pump 123 and the coolant side of the condenser 113, then splits into two branches at the hot-side three-way valve 121. Branch 1 is the cabin heating route, and branch 2 is the battery heating route. The flow rate of the two branches can be distributed through the hot-side three-way valve 121. In branch 1, the high-temperature side coolant enters the heater core 122, releases heat to the air, and then flows back to the main route. In branch 2, the high-temperature side coolant passes through port 7 and port 4 of the nine-way valve, the third water pump 128, the battery pack liquid cooling assembly 129, port 5 of the nine-way valve, and port 6 of the nine-way valve before flowing back to the main route.

[0095] The low-temperature side coolant passes sequentially through the first water pump 118, PTC 117, the coolant side of the evaporator 115, the cold-side three-way valve 120, port 9 of the nine-way valve, port 2 of the nine-way valve, the motor and electronic control assembly 127, port 3 of the nine-way valve, port 8 of the nine-way valve, and the first water pump 118. The low-temperature side coolant releases heat and cools down in the evaporator 115, and absorbs heat and heats up in the motor and electronic control assembly 127.

[0096] Operating mode 10: Cooling reheat defogging mode, the nine-way valve 124 adopts connection method four, the cold side three-way valve 120 connects to the cold air core circuit, the hot side three-way valve 121 simultaneously connects to the warm air core circuit and the high temperature coolant circuit, and the heat pump circulation circuit is configured to work.

[0097] In the cooling-reheat defogging mode, the high-temperature side refrigerant has two routes. The main route passes through the second water pump 123 and the refrigerant side of the condenser 113, and splits into two branches at the hot-side three-way valve 121. Branch 1 is the cabin reheat defogging route, and branch 2 is the outdoor heat dissipation route. The flow of the two branches can be distributed through the hot-side three-way valve 121. In branch 1, the high-temperature side refrigerant enters the heater core 122, releases heat to the air, and then flows back to the main route. In branch 2, the high-temperature side refrigerant passes through port 7 of the nine-way valve, port 1 of the nine-way valve, radiator 126, motor and electronic control assembly 127, port 3 of the nine-way valve, and port 6 of the nine-way valve before flowing back to the main route.

[0098] The low-temperature side coolant circulates sequentially through the first water pump 118, PTC 117, the coolant side of the evaporator 115, the cold-side three-way valve 120, the cold air core 119, and back to the first water pump 118. The low-temperature side coolant releases heat and cools down in the evaporator 115, and absorbs heat and warms up in the cold air core 119. Air blown by the HVAC assembly fan in the passenger compartment 130 is cooled to cold air after heat exchange in the cold air core 119 before being delivered into the passenger compartment 130.

[0099] In the battery circuit, the coolant passes through port 4 of the nine-way valve, the third water pump 128, the battery pack liquid cooling assembly 129, and port 5 of the nine-way valve for internal self-circulation and temperature equalization.

[0100] Operating Mode 11: Passenger Cabin Heating-Battery Cooling Mode. Nine-way valve 124 is connected in the first mode. Cold-side three-way valve 120 is connected to the low-temperature coolant circuit. Hot-side three-way valve 121 is connected to both the heating core circuit and the high-temperature coolant circuit. The heat pump circulation circuit is configured to operate.

[0101] In the passenger compartment heating-battery cooling mode, the high-temperature side coolant has two routes. The main route passes through the second water pump 123 and the coolant side of the condenser 113, and splits into two branches at the hot-side three-way valve 121. Branch 1 is the cabin heating route, and branch 2 is the outdoor heat dissipation route. The flow of the two branches can be distributed through the hot-side three-way valve 121. In branch 1, the high-temperature side coolant enters the heater core 122, releases heat to the air, and then flows back to the main route. In branch 2, the high-temperature side coolant passes through port 7 of the nine-way valve, port 1 of the nine-way valve, radiator 126, motor and electronic control assembly 127, port 3 of the nine-way valve, and port 6 of the nine-way valve before flowing back to the main route.

[0102] The low-temperature side coolant circulates sequentially through the first water pump 118, PTC 117, the coolant side of the evaporator 115, the cold-side three-way valve 120, port 9 of the nine-way valve, port 4 of the nine-way valve, the third water pump 128, the battery pack liquid cooling assembly 129, port 5 of the nine-way valve, port 8 of the nine-way valve, and the first water pump 118. The low-temperature side coolant releases heat and cools down in the evaporator 115, and absorbs heat and heats up in the battery pack liquid cooling assembly 129.

[0103] Operating mode 12: Passenger cabin dehumidification and heating - battery cooling mode. Nine-way valve 124 adopts connection method one. Cold side three-way valve 120 simultaneously connects the cold air core circuit and the low temperature coolant circuit. Hot side three-way valve 121 simultaneously connects the warm air core circuit and the high temperature coolant circuit. The heat pump circulation circuit is configured to work.

[0104] In the passenger compartment dehumidification and heating-battery cooling mode, the high-temperature side coolant has two routes. The main route passes through the second water pump 123 and the coolant side of the condenser 113, and splits into two branches at the hot-side three-way valve 121. Branch 1 is the cabin heating route, and branch 2 is the outdoor heat dissipation route. The flow of the two branches can be distributed through the hot-side three-way valve 121. In branch 1, the high-temperature side coolant enters the heater core 122, releases heat to the air, and then flows back to the main route. In branch 2, the high-temperature side coolant passes through port 7 of the nine-way valve, port 1 of the nine-way valve, radiator 126, motor and electronic control assembly 127, port 3 of the nine-way valve, and port 6 of the nine-way valve before flowing back to the main route.

[0105] The low-temperature side coolant has two routes. The main route passes through the first water pump 118, PTC 117, and the coolant side of the evaporator 115, and splits into two branches at the cold-side three-way valve 120. Branch 1 is the dehumidification route for the vehicle compartment, and branch 2 is the battery cooling route. The flow rate of the two branches can be distributed through the cold-side three-way valve 120. In branch 1, the low-temperature side coolant enters the cooling air core 119, absorbs heat from the air, and then flows back to the main route. In branch 2, the low-temperature side coolant passes through port 9 and port 4 of the nine-way valve, the third water pump 128, the battery pack liquid cooling assembly 129, port 5 of the nine-way valve, and port 8 of the nine-way valve before flowing back to the main route.

[0106] Operating mode 13: Passenger cabin dehumidification and heating - battery heating mode. Nine-way valve 124 adopts connection method two. Cold side three-way valve 120 simultaneously connects the cold air core circuit and the low temperature coolant circuit. Hot side three-way valve 121 simultaneously connects the warm air core circuit and the high temperature coolant circuit. The heat pump circulation circuit is configured to work.

[0107] In the passenger compartment dehumidification and heating-battery heating mode, the high-temperature side coolant has two routes. The main route passes through the second water pump 123 and the coolant side of the condenser 113, and splits into two branches at the hot-side three-way valve 121. Branch 1 is the cabin heating route, and branch 2 is the battery heating route. The flow of the two branches can be distributed through the hot-side three-way valve 121. In branch 1, the high-temperature side coolant enters the heater core 122 and releases heat to the air before returning to the main route. In branch 2, the high-temperature side coolant passes through port 7 of the nine-way valve, port 4 of the nine-way valve, the third water pump 128, the battery pack liquid cooling assembly 129, port 5 of the nine-way valve, and port 6 of the nine-way valve before returning to the main route.

[0108] The low-temperature side coolant has two routes. The main route passes through the first water pump 118, PTC 117, and the coolant side of the evaporator 115, and splits into two branches at the cold-side three-way valve 120. Branch 1 is the dehumidification route for the vehicle compartment, and branch 2 is the outdoor heat dissipation route. The flow rate of the two branches can be distributed through the cold-side three-way valve 120. In branch 1, the low-temperature side coolant enters the cold air core 119, absorbs heat from the air, and then returns to the main route, causing some water vapor in the air to condense and reduce air humidity. In branch 2, the low-temperature side coolant passes through port 9 of the nine-way valve, port 1 of the nine-way valve, radiator 126, motor and electronic control assembly 127, port 3 of the nine-way valve, and port 8 of the nine-way valve before returning to the main route.

[0109] Operating mode fourteen: Battery equalization-motor cooling mode. The nine-way valve 124 is connected in mode four, the heat pump circulation loop is not working, and the first water pump 118 is in the closed state (that is, the cold air core loop and the low temperature coolant loop are also not working). The hot side three-way valve 121 is connected to the high temperature coolant loop.

[0110] In the battery temperature equalization-motor cooling mode, the battery circuit performs internal self-circulation cooling.

[0111] The high-temperature side coolant circulates sequentially through the second water pump 123, the coolant side of the condenser 113, the hot-side three-way valve 121, port 7 of the nine-way valve, port 1 of the nine-way valve, the radiator 126, the motor and electronic control assembly 127, port 3 of the nine-way valve, port 6 of the nine-way valve, and finally back to the second water pump 123. After the high-temperature side coolant dissipates heat to the air at the radiator 126, it cools down and then absorbs heat at the motor and electronic control assembly 127 to cool the assembly.

[0112] The following section provides a detailed introduction to the mode switching method of the electric vehicle thermal management system based on the nine-way valve.

[0113] A mode switching method for an electric vehicle thermal management system based on a nine-way valve is proposed, implemented using a hierarchical collaborative control architecture. This architecture includes a thermal management system controller (decision layer) and a TMM controller (execution layer). The two controllers interact via a CAN bus. The signal interaction within the hierarchical collaborative control architecture is as follows: Figure 3 As shown.

[0114] The mode switching method includes the following five core steps:

[0115] S1: Signal Acquisition

[0116] The decision-making layer receives and integrates multi-dimensional signals from the entire vehicle, including driving status, cabin environment, human-machine interaction commands (setting temperature, AC switch), and battery and motor temperatures. Based on the multi-dimensional signals from the entire vehicle, the decision-making layer makes a comprehensive judgment, identifies the target operating condition of the system, completes the formulation of high-level strategies, and sends the target operating mode signal (HMI_MOD) to the execution layer through the CAN bus.

[0117] The execution layer receives instructions from the upper layer and drives the lower-level components. It is responsible for the precise closed-loop control of specific actuators such as the nine-way valve, three-way valve, water pump, compressor, electronic expansion valve, and PTC in the TMM integrated module (i.e., the electric vehicle thermal management system based on the nine-way valve), ensuring that the actual flow rate, temperature, pressure and other parameters of the system can quickly and stably track and achieve the target set by the decision layer.

[0118] S2: Operating Condition Recognition and Pattern Determination

[0119] The decision-making level identifies the current operating conditions of the vehicle cabin, battery, and motor, and then matches and maps one of the 14 preset operating modes of the whole vehicle based on the target operating condition combination of the three.

[0120] Cabin operating condition identification: Cabin operating conditions include cabin cooling, cabin heating, and no demand. Identify the target operating condition to be switched according to the judgment conditions given in Table 1.

[0121] Table 1: Vehicle Cabin Cooling / Heating / No Need Determination Table

[0122]

[0123] Battery operating condition identification: Battery operating conditions include battery cooling, battery heating, and self-circulation. Identify the target operating condition to be switched to according to the judgment criteria given in Table 2.

[0124] Table 2: Battery Cooling / Heating / Self-Circulation Judgment Table

[0125]

[0126] A "buffer zone" is constructed by using a hysteresis interval (i.e., the asymmetric threshold difference between the mode entry and exit conditions) to prevent the system from frequently switching modes near the critical point due to signal noise or minor fluctuations. Taking battery cooling mode identification and exit as an example, the entry condition (trigger threshold) is: when the highest battery pack temperature is ≥ the upper limit of the battery pack safety temperature (e.g., 38℃), the cooling mode is entered to ensure safety. The exit condition (release threshold) is: it does not exit immediately when the temperature drops to 38℃, but only when the lowest battery pack temperature is ≤ the lower limit of the battery pack safety temperature (e.g., 30℃) and the absolute value of the temperature difference between the battery pack inlet and outlet liquids is less than a set value (e.g., ≤2℃). The temperature difference range between 38℃ (entry) and 30℃ (exit) is the "hysteresis interval". Within this interval (e.g., 30℃~38℃), even if the battery temperature fluctuates, the system maintains the current mode, thereby effectively avoiding frequent switching of the battery at the boundary between "cooling required" and "cooling not required".

[0127] Motor operating condition identification: Motor operating condition includes sufficient motor residual heat and insufficient motor residual heat. The judgment is made according to the temperature threshold in Table 3 combined with vehicle speed correction. The judgment result provides a basis for whether only motor residual heat is used.

[0128] Table 3: Thresholds for determining sufficient / insufficient residual heat in the motor (combined with vehicle speed correction)

[0129]

[0130] In Table 3, VehSpd represents vehicle speed, and ECC_MotdT represents motor temperature.

[0131] Target pattern matching: Based on the identification results of the working conditions of the cabin, battery, and motor, match one of the 14 preset operating modes according to Table 4. Each mode corresponds to a unique combination of actuator working states.

[0132] Table 4: Operating Mode Signal Table

[0133]

[0134] S3: Command Issuance and Mapping

[0135] The decision-making layer sends the target operating mode command (HMI_MOD code) to the execution layer. The execution layer (TMM controller) focuses on component-level drive, performing precise closed-loop control of the nine-way valve position, cold / hot side three-way valve opening, water pump speed, compressor speed, electronic expansion valve opening, and PTC power to ensure that the actual physical parameters quickly and stably track the upper-level target. Each mode corresponds to the opening of the nine-way valve, the cold side three-way valve, the hot side three-way valve, and the working status of the core actuator, as set in Table 5.

[0136] Table 5: Correspondence between 14 operating modes and actuator working states

[0137]

[0138] S4: Smooth Timing Switching

[0139] The thermal management system's operations are divided into dynamic mode switching logic and system start-up / shutdown logic. Asynchronous timing control is strictly executed according to the topological relationships and pressure response characteristics between components to avoid hydraulic shock and pressure fluctuations. Upon receiving a mode switching signal, anti-jitter judgment is performed, and the state of each actuator is adjusted strictly according to the predetermined dynamic timing. The "speed reduction and position preservation" and "step-by-step asynchronous response" mechanisms are used to eliminate hydraulic shock and pressure fluctuations.

[0140] Dynamic mode switching logic:

[0141] During vehicle operation, when the decision-making layer issues a mode switching command, the execution layer first performs a 1-second anti-shake delay judgment to filter transient signal jumps. After confirming a valid switch, the execution layer needs to perform a conditional branch judgment: if the change between the old and new modes does not involve a change in the position of the nine-way valve, each actuator directly performs closed-loop follow-up adjustment; if... Figure 4 As shown, if the switching process involves a change in the position of the nine-way valve, the following timing control chain must be strictly activated to avoid drastic hydraulic and pressure fluctuations:

[0142] 1) Power Source Coordinated Speed ​​Reduction (Vibration Reduction and Pressure Relief Stage): When it is confirmed that the nine-way valve needs to be reversed, the compressor is first controlled to actively reduce its speed, and then the water pumps in each circuit are linked to synchronously reduce their speed. Engineering objective: By reducing the speed of the power components, the kinetic energy of the large circulation of the liquid circuit system is quickly removed, and the high and low pressure difference of the refrigerant circuit is compressed to within the safe reversing threshold, preventing hard reversing under high pressure difference conditions from causing valve core wear or mechanical jamming.

[0143] 2) Valve body channel reconfiguration (reversing transition stage): After the power source decelerates, the nine-way valve is first driven to switch its position. After the nine-way valve is precisely positioned and locked, the cold / hot side three-way valve is then switched to the target opening. Project objective: To ensure that the main pipe level (nine-way valve) flow channel structure is finalized first, followed by local flow distribution by the branch level (three-way valve) flow channels, ensuring the uniqueness of the water circuit topology reconfiguration.

[0144] 3) Target Loop Re-pressurization (Dynamic Tracking Phase): After the valve body channel reconstruction is completed, the water pump control (restoring the target speed), compressor control (speed boost and pressurization), and electronic expansion valve control (superheat closed-loop regulation) are activated sequentially as needed. Engineering objective: To re-establish a stable fluid dynamic field and thermodynamic cycle within the new flow channel structure, enabling the vehicle's actual flow, temperature, and pressure parameters to quickly and smoothly track the target setpoints of the new mode.

[0145] System start / stop logic:

[0146] When the system is first powered on or shuts down upon receiving a vehicle hibernation command, it executes the following: Figure 5 The chain-like timing control is shown. When the system receives a start command, it first establishes the physical liquid circuit channels between the nine-way valve and the three-way valve; then the water pump starts to establish a stable coolant circulation flow; finally, the electronic expansion valve initializes to the preset opening degree, and the compressor starts to build pressure, ensuring the safety of the refrigerant circuit.

[0147] When the system receives a shutdown command, to prevent local abnormal high pressure or water hammer effect of the refrigerant, the compressor and water pump first work together to reduce their speed to zero, cut off the power source and eliminate dynamic pressure difference; then the three-way valve and nine-way valve sequentially perform reset or power-off position switching; finally, the electronic expansion valve is closed to achieve dynamic locking and safe pressure relief of the refrigerant circuit.

[0148] S5: Security Classification Protection

[0149] The execution layer monitors the operating parameters of core components in real time, performs full-process safety protection of "tiered early warning + fault shutdown", and links with the decision-making layer to switch to safety mode when a severe fault is triggered.

[0150] Compressor safety protection: Implement exhaust temperature protection, high pressure protection, and low pressure protection according to Tables 6 to 8 respectively.

[0151] Table 6: Compressor Discharge Temperature Protection Strategy

[0152]

[0153] Where ECC_EasOutlT is the compressor discharge temperature.

[0154] Table 7: High-Pressure Protection Strategy for Compressors (Applicable Operating Conditions)

[0155]

[0156] Where P is the compressor pressure.

[0157] Table 8: Compressor Low-Pressure Protection Strategy (Applicable Operating Conditions)

[0158]

[0159] Valve body and water pump fault protection: If the valve core of the nine-way valve is stuck for more than 10% for 500ms, the opening of the three-way valve is not adjusted within 1s, or the speed / flow rate of the water pump does not reach the threshold (the lower limit of the expected flow rate corresponding to the target speed, such as 70%~80% of the target flow rate) after 300ms of water pump start-up, the system will shut down or reduce to a safe opening according to the preset strategy.

[0160] System-level fault protection: When any actuator triggers a fault shutdown, the execution layer immediately cuts off the enable signal of the actuator and feeds back the fault signal to the decision layer; after receiving the fault signal, the decision layer switches to the safety mode, shuts down the heat pump circulation loop, and retains only the necessary cooling / heating loops to ensure the safe operation of the battery and motor.

[0161] In summary, the thermal management system controller collects diverse parameters from the vehicle compartment, battery, motor, and environment to identify operating conditions and determine 14 operating modes, outputting target temperature and mode commands. The TMM controller receives commands from the upper layer, achieving precise closed-loop control of actuators such as the nine-way valve, three-way valve, water pump, compressor, and electronic expansion valve. It also incorporates anti-shake mechanisms for mode switching, component start-up and shutdown sequencing, waste heat recovery grading, and safety protection strategies. This invention achieves flexible heat distribution and efficient coordination across the various loops of the thermal management system, improving system temperature control accuracy and energy utilization efficiency, reducing energy consumption, and ensuring stable and reliable system operation under all operating conditions.

Claims

1. A mode switching method for an electric vehicle thermal management system based on a nine-way valve, characterized in that, The electric vehicle thermal management system includes a motor control main circuit, a motor control auxiliary circuit, a battery circuit, a passenger compartment circuit, a cold air core circuit, a low-temperature coolant circuit, a warm air core circuit, a high-temperature coolant circuit, a heat pump circulation circuit, a cold-side three-way valve (120), a hot-side three-way valve (121), and a nine-way valve (124). The main circuit of the motor control is connected to ports 1 and 3 of the nine-way valve, respectively. The auxiliary circuit of the motor control is connected to ports 2 and 3 of the nine-way valve, respectively. The battery circuit is connected to ports 4 and 5 of the nine-way valve, respectively. The battery circuit has a third water pump (128). The cold air core circuit is thermally coupled to the heat pump circulation circuit through the evaporator (115). The inlet and outlet of the cold-side three-way valve (120) are connected to the cold air core circuit. At the same time, the cold air core circuit is thermally coupled to the crew compartment circuit through the cold air core (119). The cold air core circuit has a first water pump (118) and a PTC (117). The low-temperature coolant circuit is formed by adding a parallel cold air core pipeline on the basis of the cold air core circuit. The parallel cold air core pipeline includes a connection between port 9 of the nine-way valve and the cold-side three-way valve (120). The pipeline includes the second outlet end of the heating core circuit and the pipeline connecting the 8th port of the nine-way valve and the coolant outlet end of the cold air core (119). The heating core circuit is thermally coupled to the heat pump circulation circuit through the condenser (113). The inlet end and the first outlet end of the hot-side three-way valve (121) are connected to the heating core circuit. At the same time, the heating core circuit is thermally coupled to the crew compartment circuit through the heating core (122). The heating core circuit has a second water pump (123). The high-temperature coolant circuit is formed by adding a parallel heating core pipeline on the basis of the heating core circuit. The parallel heating core pipeline includes the pipeline connecting the 7th port of the nine-way valve and the second outlet end of the hot-side three-way valve (121), and the pipeline connecting the 6th port of the nine-way valve and the coolant outlet end of the heating core (122). The heat pump circulation circuit has a compressor (112) and an electronic expansion valve (114). By controlling the connection mode of the cold-side three-way valve (120), the hot-side three-way valve (121) and the nine-way valve (124), and configuring the heat pump circulation loop to work or not work, the main circuit of motor control, the auxiliary circuit of motor control, the battery circuit, the cold air core circuit, the low temperature coolant circuit, the warm air core circuit and the high temperature coolant circuit can form different circuits, so as to realize that the electric vehicle thermal management system works in different operating modes; The mode switching method is implemented based on a hierarchical collaborative control architecture of the decision-making layer and the execution layer, including: S1: Signal Acquisition: The decision-making layer receives and integrates multi-dimensional signals from the entire vehicle, including driving status, cabin environment, human-machine interaction commands, battery and motor temperatures; S2: Operating Condition Identification and Mode Determination: The decision-making layer identifies the current state of the vehicle compartment, battery, and motor, and then matches and maps one of the several preset operating modes of the vehicle based on the target operating condition combination of the three. S3: Command Issuance and Mapping: The decision-making layer issues the target operating mode command to the execution layer, and the execution layer performs closed-loop control on each actuator of the electric vehicle thermal management system. S4: Smooth timing switching: The action execution of the thermal management system is divided into dynamic mode switching logic and system start-up and shutdown logic. After receiving the mode switching signal, anti-jitter judgment is performed, and the state of each actuator is adjusted according to the predetermined dynamic timing. The hydraulic shock and pressure fluctuation are eliminated by using the "speed reduction and position preservation" and "step-by-step asynchronous response" mechanisms. S5: Safety graded protection: The execution layer monitors the operating parameters of core components in real time, performs full-process safety protection of "graded early warning + fault shutdown", and links the decision layer to switch to safety mode when a serious fault is triggered; core components include compressor, valve body and water pump.

2. The mode switching method for the electric vehicle thermal management system based on a nine-way valve according to claim 1, characterized in that, In step S2, the cabin operating conditions include cabin cooling, cabin heating, and no demand. The cabin cooling condition is entered when the cabin temperature is ≥ the cabin set temperature, and exited when the user manually turns off the air conditioner or the cabin set temperature is ≥ the outdoor ambient temperature. The cabin heating condition is entered when the cabin temperature is ≤ the cabin set temperature, and exited when the user manually turns off the air conditioner or the cabin set temperature is ≤ the outdoor ambient temperature. The condition for entering the no-demand operating mode is that the user manually turns off the air conditioner, and the condition for exiting is that the conditions for entering the vehicle cabin cooling or heating operating mode are met.

3. The mode switching method for the electric vehicle thermal management system based on a nine-way valve according to claim 1, characterized in that, In step S2, the battery operating conditions include battery cooling, battery heating and self-circulation. The entry condition for battery cooling is that the highest temperature of the battery pack is ≥ the upper limit temperature of the battery pack safety, and the exit condition is that |the temperature difference between the inlet and outlet liquids of the battery pack| < the battery cooling exit value and the lowest temperature of the battery pack is ≤ the lower limit temperature of the battery pack safety. The entry condition for battery heating mode is that the lowest temperature of the battery pack is ≤ the lower limit temperature of the battery pack, and the exit condition is that the temperature difference between the inlet and outlet of the battery pack is greater than the battery heating exit value and the highest temperature of the battery pack is ≥ the upper limit temperature of the battery pack. The entry condition for self-circulation mode is that the highest temperature of the battery pack is ≤ the upper limit temperature of the battery pack or the lowest temperature of the battery pack is ≥ the lower limit temperature of the battery pack, and the exit condition is that the highest temperature of the battery pack is ≥ the upper limit temperature of the battery pack or the lowest temperature of the battery pack is ≤ the lower limit temperature of the battery pack.

4. The mode switching method for the electric vehicle thermal management system based on a nine-way valve according to claim 1, characterized in that, In step S2, the motor operating conditions include sufficient motor residual heat and insufficient motor residual heat. Different motor temperature thresholds are determined according to the vehicle speed, and then the motor temperature is used for judgment. When the motor temperature is greater than the motor temperature threshold, the motor residual heat is sufficient; otherwise, the motor residual heat is insufficient.

5. The mode switching method for the electric vehicle thermal management system based on a nine-way valve according to claim 1, characterized in that, In step S4, the dynamic mode switching logic is as follows: during the operation of the vehicle, when the decision layer issues a mode switching command, the execution layer first performs a set time anti-shake delay judgment to filter signal transient jumps. Once the switch is confirmed to be valid, the execution layer will determine the condition branch: if the switch does not involve a change in the position of the nine-way valve, each actuator will directly perform closed-loop follow adjustment; if the switch involves a change in the position of the nine-way valve, the set timing control chain will be activated to avoid drastic hydraulic and pressure fluctuations.

6. The mode switching method for the electric vehicle thermal management system based on a nine-way valve according to claim 5, characterized in that, The established timing control chain includes: 1) Power source coordinated deceleration: When it is confirmed that the nine-way valve needs to be reversed, the compressor is first controlled to actively reduce speed, and then the water pumps in each circuit are linked to synchronously reduce speed; 2) Valve body channel reconfiguration: After the power source decelerates, the nine-way valve is first driven to perform the work position switching; after the nine-way valve is accurately positioned and locked, the cold / hot side three-way valve is then switched to the target opening degree; 3) Target circuit re-pressure: After the valve body channel is reconstructed, activate the water pump control, compressor control and electronic expansion valve control in sequence as needed.

7. The mode switching method for the electric vehicle thermal management system based on a nine-way valve according to claim 1, characterized in that, In step S4, the system start-stop logic is as follows: When the system receives a start command, it first establishes the physical liquid circuit channels of the nine-way valve and the three-way valve; then the water pump starts to establish a stable coolant circulation flow; finally, the electronic expansion valve initializes according to the preset opening degree, and the compressor starts to build pressure to ensure the safety of the refrigerant circuit; when the system receives a shutdown command, the compressor and water pump first work together to reduce speed to zero, cut off the power source and eliminate dynamic pressure difference; then the three-way valve and the nine-way valve sequentially perform reset or power-off position-keeping switching; finally, the electronic expansion valve is closed to achieve dynamic locking and safe pressure release of the refrigerant circuit.

8. The mode switching method for the electric vehicle thermal management system based on a nine-way valve according to claim 1, characterized in that, In step S5, the compressor safety protection includes: exhaust temperature protection, high pressure protection and low pressure protection, which are executed according to the warning stage and the shutdown stage; The exhaust temperature protection determines the warning stage and the shutdown stage based on the compressor exhaust temperature and different exhaust temperature thresholds. During the warning stage, a speed reduction action is performed. During the shutdown stage, the compressor enable is immediately cut off and a fault signal is fed back. The recovery condition is that the compressor exhaust temperature drops below the recovery temperature threshold and stabilizes for a first specified time. The high-pressure protection determines the warning stage and the shutdown stage based on the compressor pressure and different high-pressure thresholds. During the warning stage, a speed reduction action is performed. During the shutdown stage, the compressor enable is immediately cut off, the electronic expansion valve is activated, and a fault signal is fed back. The recovery condition is that the compressor pressure drops below the first recovery pressure threshold and stabilizes for a second specified time. The low-pressure protection determines the warning stage and the shutdown stage based on the compressor pressure and different low-pressure thresholds. During the warning stage, it performs a speed reduction action or reduces the speed and activates the corresponding valves. During the shutdown stage, it immediately cuts off the compressor enable or immediately cuts off the compressor enable and activates the corresponding valves, while feeding back a fault signal. The recovery condition is that the compressor pressure rises above the second recovery pressure threshold and stabilizes for a third specified time.

9. The mode switching method for the electric vehicle thermal management system based on a nine-way valve according to claim 1, characterized in that, In step S5, valve body and water pump fault protection: if the valve core of the nine-way valve is stuck and the deviation is greater than 10% for 500ms, if the opening of the three-way valve is not adjusted within 1s, or if the speed / flow rate of the water pump does not reach the threshold after 300ms of starting, the system will shut down or reduce to a safe opening according to the preset strategy.

10. The mode switching method for the electric vehicle thermal management system based on a nine-way valve according to claim 1, characterized in that, In step S5, when any actuator triggers a fault shutdown, the execution layer immediately cuts off the enable signal of the actuator and feeds back the fault signal to the decision layer. After receiving the fault signal, the decision layer switches to the safety mode, shuts down the heat pump circulation loop, and retains only the necessary cooling / heating loops to ensure the safe operation of the battery and motor.

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