Electric motor coach thermal management system and multi-mode control method

Abstract

The invention discloses an electric motor coach heat management system and a multi-mode control method, and the electric motor coach heat management system comprises a heat pump system, a cold water system, a hot water system, a cold and hot core body, a cold and hot temperature regulating unit, a battery temperature regulator, an external heat exchanger and an electric control and motor ATS cooling unit, the heat pump system is connected with the hot water system through the air cooler; the cold and hot core body, the cold and hot temperature regulating unit, the battery temperature regulator and the external heat exchanger are selectively communicated to a cold water system or a hot water system through valve switching; and under the working condition that the cold water system supplies cold, the battery thermolator is arranged at the downstream of the cold and hot core body and the cold and hot temperature adjusting unit, so that the cold energy in the first secondary refrigerant loop flows through the cold and hot core body and the cold and hot temperature adjusting unit and then enters the battery thermolator to cool the battery. Through integrated linkage of the heat pump, the cold water system and the hot water system, the secondary heat exchange loop design is combined, energy gradient utilization and efficient cooperation are achieved, energy consumption is remarkably reduced, and the endurance is prolonged.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal management of electric buses, and in particular relates to a thermal management system and a multi-mode control method for electric buses. Background Art

[0002] Amid the rapid development of the new energy vehicle industry, electric buses, as a core vehicle in the public transportation sector, face a crucial impact on the performance of their thermal management systems, impacting vehicle range, core component lifespan, and ride comfort. Electric buses must simultaneously meet multiple temperature control requirements: First, the battery, motor, and electronic control system (collectively, the "three-electric system") must be maintained within an optimal operating temperature range to ensure efficiency and safety. For example, when the battery is discharging, the water inlet temperature of the battery thermostat must be set at approximately 20°C, and the water outlet temperature of the electronic control motor must be controlled below 65°C. Second, the cockpit and passenger compartment must maintain a comfortable temperature and humidity environment, while also balancing system energy consumption and environmental adaptability. Typically, the air conditioning water inlet temperature for both cockpit and passenger compartments is set at approximately 7-10°C.

[0003] The existing technology has the following problems:

[0004] First, energy utilization is low and there's a lack of coordination. Functions like heat dissipation for the three-electric system and cabin environmental control are mostly implemented through independent subsystems, without coordination between them. For example, in spring and autumn, although ambient temperatures are lower than battery temperatures, battery cooling requires refrigeration units, consuming additional electricity. In winter, heating relies on PTC heating, failing to utilize waste heat from the three-electric system, resulting in high energy consumption and reduced range. In summer, battery cooling and cabin air conditioning (cockpit and passenger compartment) require different cold water temperatures, but energy cascade utilization is not implemented, resulting in wasted energy.

[0005] Second, the system lacks adaptability to extreme environments and suffers from low heating efficiency. In extremely cold environments below -25°C, battery heating relies heavily on PTC, which is inefficient and consumes a lot of power. The system struggles to effectively utilize ambient thermal energy or waste heat, failing to meet the rapid preheating requirements for batteries in low temperatures, and also impacting the overall performance of the heat pump system.

[0006] In summary, existing technologies have limitations in energy utilization and environmental adaptation, and an efficient and coordinated thermal management system is urgently needed. Summary of the Invention

[0007] In order to solve the above technical problems, the present invention proposes a thermal management system and a multi-mode control method for an electric bus.

[0008] In order to achieve the above object, the technical solution of the present invention is as follows:

[0009] In one aspect, the present invention discloses a thermal management system for an electric bus, comprising: a heat pump system, a chilled water system, and a hot water system. The heat pump system comprises: a compressor, an air cooler, an evaporator, and a refrigerant circulation loop connecting the various components. The heat pump system is connected to the chilled water system via the evaporator, and the heat pump system is connected to the hot water system via the air cooler.

[0010] The cold water system includes: a cold water pump and a first coolant circuit connecting various components;

[0011] The hot water system includes a hot water pump, a floor radiator, and a second refrigerant circuit connecting various components. The floor radiator is used to heat the passenger compartment.

[0012] The electric bus thermal management system further includes: a hot and cold core, a hot and cold temperature regulating unit, a battery thermostat, and an off-board heat exchanger. The hot and cold core, the hot and cold temperature regulating unit, the battery thermostat, and the off-board heat exchanger are selectively connected to the first refrigerant circuit or the second refrigerant circuit through valve switching.

[0013] The hot and cold core is used to adjust the temperature of the cockpit, and the hot and cold thermostat unit is used to adjust the temperature of the passenger compartment;

[0014] The battery thermostat is used to regulate the battery temperature. When the chilled water system is used for cooling, the battery thermostat is located downstream of the hot and cold cores and the hot and cold temperature control unit. This allows the cold air in the first refrigerant circuit to flow through the hot and cold cores and the hot and cold temperature control unit before entering the battery thermostat to cool the battery.

[0015] The off-board heat exchanger is used to discharge the heat generated by the hot water system to the outside environment, or absorb heat from the outside environment and transfer it to the cold water system;

[0016] The electric bus thermal management system also includes: an electronic control and motor ATS cooling unit, which can be switched by a valve to selectively connect to the first coolant circuit to achieve heat exchange with the coolant of the cold water system, and / or form an independent circulation pipeline to use its own ATS heat exchanger to directly discharge heat to the external environment. The electronic control and motor ATS cooling unit is used to dissipate heat for the electronic control and motor;

[0017] The cooling energy generated by the evaporator of the heat pump system is transferred to the chilled water system through the primary refrigerant circuit, forming a secondary cooling circuit;

[0018] The heat generated by the air cooler of the heat pump system is transferred to the hot water system through the second refrigerant circuit, forming a secondary heat circuit;

[0019] The cooling secondary circuit and the heating secondary circuit work independently to realize the distribution of cooling and heating respectively.

[0020] On the basis of the above technical solution, the following improvements can be made:

[0021] As a preferred solution, the electronic control and motor ATS cooling unit includes: electronic control, motor, ATS circulation pump and ATS heat exchanger.

[0022] As a preferred solution, the cold water system further comprises: a refrigerator, the refrigerator being used to refrigerate items;

[0023] The hot water system also includes: a high-temperature cabinet, which is used to heat items.

[0024] As a preferred solution, the hot and cold temperature control unit includes: a plurality of fan coil units arranged in parallel, and the fan coil units are installed on the top of the vehicle.

[0025] As a preferred solution, the heat pump system uses CO2 as refrigerant, and the heat pump system includes: a CO2 refrigeration compressor, an air cooler, a regenerator, a drying filter, an electronic expansion valve, an evaporator, and a liquid receiver;

[0026] The CO2 refrigeration compressor, air cooler, regenerator, filter drier, electronic expansion valve, evaporator, and liquid receiver are connected through pipelines to form a CO2 refrigerant circulation loop.

[0027] On the other hand, the present invention discloses a multi-mode control method for an electric bus thermal management system, which uses any of the above-mentioned electric bus thermal management systems to achieve thermal management, specifically controlling the operation of a heat pump system according to different seasons.

[0028] As a preferred solution, the heat pump system does not work in spring and autumn;

[0029] The electronic control and motor ATS cooling units are switched via valves and connected in series with the battery thermostat to form an independent three-electric circulation loop.

[0030] Open the corresponding valve of the cold water system so that the heat generated by the battery, electronic control and motor in the three-electric circulation loop can be directly discharged to the outside environment using the ATS heat exchanger under the action of the ATS circulation pump.

[0031] As a preferred solution, in summer, the heat pump system is started for cooling, and the cooling energy generated by the evaporator is transferred to the chilled water system through the first refrigerant loop;

[0032] Switching valves connect the hot and cold cores, the hot and cold temperature control units, and the battery thermostat to the first coolant circuit respectively;

[0033] Open the corresponding valve of the cold water system, driving the brine coolant under the action of the cold water pump to flow through the parallel hot and cold cores, the hot and cold temperature control units, the first bypass branch, and then into the parallel battery thermostat and the second bypass branch. The flow rate and temperature of the brine coolant flowing through the battery thermostat are adjusted by the valves on the first bypass branch, the second bypass branch, and the battery thermostat branch, and the battery thermostat is used to cool the battery;

[0034] The electronic control and motor ATS cooling units are switched by valves to form independent circulation loops that are not connected to the primary coolant loop. The heat from the electronic control and motor is discharged directly to the outside environment using the ATS heat exchanger.

[0035] The heat generated by the air cooler is transferred to the hot water system through the second refrigerant circuit;

[0036] Switching the valve to connect the off-board heat exchanger to the second refrigerant circuit;

[0037] Open the corresponding valve of the hot water system and drive the coolant to dissipate heat through the external heat exchanger under the action of the hot water pump.

[0038] As a preferred solution, in winter, the heat pump system is started for heating;

[0039] Switching valves to connect the battery thermostat and the off-vehicle heat exchanger to the first coolant circuit respectively;

[0040] The electronic control and motor ATS cooling units are switched through valves, not forming an independent circulation loop, but connected to the first coolant loop and connected in parallel with the battery thermostat to form a three-electric branch.

[0041] When the temperature of the refrigerant in the first refrigerant circuit is lower than the ambient temperature, the corresponding valve of the cold water system is opened, so that the three-electric branch is connected in series with the off-vehicle heat exchanger. The heat generated by the battery, electronic control, and motor in the three-electric branch, the heat absorbed from the environment by the ATS heat exchanger, and the heat absorbed from the environment by the off-vehicle heat exchanger are transferred to the evaporator of the heat pump system through the first refrigerant circuit, serving as a low-temperature heat source for the heat pump system. Alternatively, when the temperature of the refrigerant in the first refrigerant circuit is higher than the ambient temperature, the corresponding valve of the cold water system is opened, so that the heat generated by the battery, electronic control, and motor in the three-electric branch is transferred to the evaporator of the heat pump system through the first refrigerant circuit, serving as a low-temperature heat source for the heat pump system.

[0042] The heat generated by the air cooler is transferred to the hot water system through the second refrigerant circuit;

[0043] Switching valves connect the hot and cold cores and the hot and cold temperature control units to the second refrigerant circuit respectively;

[0044] Open the corresponding valve of the hot water system to drive the coolant to flow through the parallel hot and cold cores, hot and cold temperature control units and floor radiators under the action of the hot water pump.

[0045] As a preferred solution, when the vehicle is parked and charging in the cold winter, the heat pump system is activated for heating;

[0046] Switching the valve to connect the off-board heat exchanger to the first refrigerant circuit;

[0047] The electronic control and motor ATS cooling units are switched through valves and do not form independent circulation loops, but are connected to the first coolant loop;

[0048] When the temperature of the brine in the first brine loop is lower than the ambient temperature, the corresponding valve of the chilled water system is opened, so that the electronic control and motor ATS cooling unit is connected in series with the off-vehicle heat exchanger, and the heat generated by the electronic control and motor, the heat absorbed from the environment by the ATS heat exchanger, and the heat absorbed from the environment by the off-vehicle heat exchanger are transferred to the evaporator of the heat pump system through the first brine loop, serving as a low-temperature heat source for the heat pump system; or, when the temperature of the brine in the first brine loop is higher than the ambient temperature, the corresponding valve of the chilled water system is opened, so that the heat generated by the electronic control and motor is transferred to the evaporator of the heat pump system through the first brine loop, serving as a low-temperature heat source for the heat pump system;

[0049] Switching the valve to connect the battery thermostat to the second coolant circuit;

[0050] The heat generated by the air cooler is transferred to the hot water system through the second refrigerant circuit;

[0051] Open the corresponding valve of the hot water system and drive the coolant to flow through the battery thermostat under the action of the hot water pump.

[0052] The present invention discloses a thermal management system and a multi-mode control method for an electric bus, which have the following beneficial effects:

[0053] First, efficient energy transfer is achieved through the integrated linkage of heat pumps, cold water, and hot water systems, combined with the design of a secondary heat exchange circuit.

[0054] Second, during summer cooling, the low-temperature refrigerant from the evaporator first flows through the cockpit heating and cooling core and the passenger compartment heating and cooling units to meet cabin cooling requirements. The heated refrigerant then enters the battery thermostat to cool the batteries. This not only ensures that the refrigerant temperature entering the batteries meets the required cooling requirements, but also fully utilizes the cooling capacity, reduces inefficient consumption, and achieves cascaded energy utilization and efficient synergy, significantly reducing energy consumption and extending battery life.

[0055] Third, in winter, the heat pump unit uses three-electric heat recovery technology to use the cold energy generated by the evaporator to cool the three electrics (battery, motor, and electronic control), and uses the heat generated by the air cooler to heat the vehicle cabin (cockpit and passenger compartment). Not only are the cold and heat energy of the heat pump unit fully utilized at the same time, the comprehensive energy efficiency coefficient of the heat pump is increased by more than 1 times, and the problem of poor performance of the heat pump or even inability to work normally in cold weather is solved.

[0056] Fourth, in spring and autumn, the battery and the electronically controlled motor are connected in series, and all the heat generated by the three electrics is discharged to the environment through the ATS heat exchanger. The environment is used to cool the battery, and the heat pump system does not need to work, which significantly reduces energy consumption.

[0057] Fifth, through multi-loop design and valve switching logic, precise adaptation to changes in cold and hot loads and extreme climates in different seasons and working conditions is achieved, solving the problem of weak environmental adaptability of traditional systems.

[0058] Sixth, on the basis of meeting core thermal management requirements, the vehicle's functional richness and riding experience are enhanced through component integration and collaborative control. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0060] Figure 1 This is a block diagram of the electric bus thermal management system provided by an embodiment of the present invention.

[0061] Figure 2 This is a block diagram of the electric bus thermal management system (spring and autumn) provided by an embodiment of the present invention.

[0062] Figure 3 This is a block diagram of the electric bus thermal management system (summer) provided by an embodiment of the present invention.

[0063] Figure 4 This is a block diagram of the electric bus thermal management system (winter) provided by an embodiment of the present invention.

[0064] Figure 5 This is a block diagram of the electric bus thermal management system (parking in severe winter weather) provided by an embodiment of the present invention.

[0065] Among them: 1-heat pump system, 11-CO2 refrigeration compressor, 12-air cooler, 13-regenerator, 14-drying filter, 15-electronic expansion valve, 16-evaporator, 17-liquid reservoir, 2-cold water system, 21-cold water pump, 22-freezer, 3-hot water system, 31-hot water pump, 32-floor radiator, 33-high temperature cabinet, 4-cold and hot core, 5-cold and hot temperature control unit, 51-fan coil, 6-battery thermostat, 7-outdoor heat exchanger, 8-electronic control and motor ATS cooling unit, 81-electronic control, 82-motor, 83-ATS circulation pump, 84-ATS heat exchanger, 85-ATS circulation pipeline, 91-first bypass branch, 92-second bypass branch. DETAILED DESCRIPTION

[0066] The preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0067] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0068] The expression “including” an element is an “open” expression. The “open” expression only means that the corresponding components or steps exist, and should not be interpreted as excluding additional components or steps.

[0069] In order to achieve the purpose of the present invention, some embodiments of the electric bus thermal management system and the multi-mode control method, such as Figure 1 As shown, the thermal management system of the electric bus includes: a heat pump system 1, a cold water system 2 and a hot water system 3. The heat pump system 1 includes: a compressor, an air cooler 12, an evaporator 16 and a refrigerant circulation loop connecting the various components. The heat pump system 1 is connected to the cold water system 2 through the evaporator 16, and the heat pump system 1 is connected to the hot water system 3 through the air cooler 12.

[0070] The cold water system 2 includes: a cold water pump 21 and a first coolant circuit connecting various components; the hot water system 3 includes: a hot water pump 31, a floor radiator 32 and a second coolant circuit connecting various components. The floor radiator 32 is used to heat the passenger compartment.

[0071] The thermal management system of the electric bus also includes: a hot and cold core 4, a hot and cold temperature control unit 5, a battery thermostat 6 and an external heat exchanger 7. The hot and cold core 4, the hot and cold temperature control unit 5, the battery thermostat 6 and the external heat exchanger 7 are selectively connected to the first refrigerant circuit or the second refrigerant circuit through valve switching.

[0072] The hot and cold core 4 is used to adjust the temperature of the cockpit, and the hot and cold temperature control unit 5 is used to adjust the temperature of the passenger compartment.

[0073] The battery thermostat 6 is used to adjust the battery temperature. When the cold water system 2 is supplying cooling, the battery thermostat 6 is arranged downstream of the hot and cold core 4 and the hot and cold temperature control unit 5, so that the cold in the first refrigerant circuit flows through the hot and cold core 4 and the hot and cold temperature control unit 5, and then enters the battery thermostat 6 to cool the battery.

[0074] The off-vehicle heat exchanger 7 is used to discharge the heat generated by the hot water system 3 to the outside environment, or absorb heat from the outside environment and transfer it to the cold water system 2.

[0075] The thermal management system of the electric bus also includes: an electronic control and motor ATS cooling unit 8. The electronic control and motor ATS cooling unit 8 can be switched through a valve to selectively connect to the first refrigerant circuit to achieve hot and cold interaction with the refrigerant of the cold water system 2, and / or form an independent circulation pipeline to use its own ATS heat exchanger 84 to discharge heat directly to the outside environment of the vehicle. The electronic control and motor ATS cooling unit 8 is used to dissipate heat for the electronic control 81 and the motor 82.

[0076] The cooling capacity generated by the evaporator 16 of the heat pump system 1 is transferred to the cold water system 2 through the first refrigerant circuit, forming a cooling secondary circuit; the heat generated by the air cooler 12 of the heat pump system 1 is transferred to the hot water system 3 through the second refrigerant circuit, forming a heat secondary circuit; the cooling secondary circuit and the heat secondary circuit operate independently to realize the distribution of cooling capacity and heat respectively.

[0077] The valves involved in the thermal management system of an electric bus may include, but are not limited to, a three-way reversing valve (L), a flow regulating valve (R), a check valve (H), etc.

[0078] It is worth noting that multiple off-board radiators can be connected in parallel in this system.

[0079] The present invention discloses a thermal management system for an electric bus, which has the following beneficial effects:

[0080] First, the present invention places the battery thermostat 6 downstream of the hot and cold core 4 and the hot and cold temperature control unit 5. This allows the cooling capacity of the first refrigerant circuit to first meet the cooling needs of the cockpit (hot and cold core 4) and the passenger compartment (hot and cold temperature control unit 5). The heated refrigerant then enters the battery thermostat 6 to cool the batteries. This tiered utilization model, with the cabin first and the batteries second, allows the same cooling capacity to be fully utilized in different temperature demand scenarios, avoiding the waste caused by directly supplying cooling capacity to a single device in traditional systems and improving the energy efficiency of the chilled water system 2.

[0081] Second, to address winter heating's reliance on PTC electric heating, the system utilizes the synergy between heat pump system 1 and chilled water system 2 to recover waste heat from the three electrical systems (battery, electronic control 81, and motor 82). For example, in winter mode, chilled water system 2 switches valves to direct waste heat from the three electrical systems into the heat pump evaporator 16, raising the evaporation temperature and heating capacity. This heat is then transferred to hot water system 3 via air cooler 12 to heat the cabin. This design reduces reliance on PTC heating, lowers heating energy consumption, and significantly extends driving range.

[0082] Third, heat pump system 1 connects to chilled water system 2 (the secondary cooling circuit) via evaporator 16 and to hot water system 3 (the secondary heating circuit) via air cooler 12, with both circuits operating independently. This design avoids the mutual interference between cooling and heating in traditional systems, ensuring precise coordination between the three-system temperature control and cabin environmental regulation. For example, during summer cooling, cooling is centrally supplied to the cabin and batteries, while during winter heating, heating is prioritized to meet cabin needs, resolving the pain point of "lack of coordination between subsystems."

[0083] Fourth, the off-board heat exchanger 7 can achieve "bidirectional functionality" through valve switching. In winter, it absorbs heat energy from the environment and transfers it to the evaporator 16 via the chilled water system 2, enhancing the heat pump's low-temperature heating capabilities. In summer, it acts as a heat sink, discharging heat generated by the air cooler 12 and waste heat from the three electrical systems directly to the environment, preventing system efficiency degradation at high temperatures.

[0084] Fifth, the electronic control and motor ATS cooling unit 8 can be switched via a valve to select either "independent circulation" or "connected to chilled water system 2." During high summer temperatures, the independent circulation directly dissipates heat through the ATS heat exchanger 84, preventing waste heat from the three electrical systems from affecting the cooling capacity of chilled water system 2. In winter, the unit can connect to chilled water system 2 to recycle waste heat.

[0085] In order to further optimize the implementation effect of the present invention, in some other embodiments, the remaining characteristic technologies are the same, the difference is that the electronic control and motor ATS cooling unit 8 includes: electronic control 81, motor 82, ATS circulation pump 83 and ATS heat exchanger 84.

[0086] With the above technical solution, the electronic control and motor ATS cooling unit 8 uses the ATS circulation pipeline 85 to achieve independent circulation. The structure and function of the electronic control and motor ATS cooling unit 8 are clear, ensuring the reliable implementation of its independent circulation or waste heat recovery function, and improving system stability.

[0087] In order to further optimize the implementation effect of the present invention, in some other embodiments, the remaining characteristic technologies are the same, except that the cold water system 2 also includes: a refrigerator 22, which is used to refrigerate items; the hot water system 3 also includes: a high-temperature cabinet 33, which is used to heat items.

[0088] By adopting the above technical solution, the vehicle can have both refrigeration (such as fresh food and medicine) and heating (such as meals) functions in public transportation operations, thereby improving its practicality.

[0089] It is worth noting that the cold cabinet 22 is connected to the first refrigerant circuit through a valve, and the high-temperature cabinet 33 is connected to the second refrigerant circuit through a valve. They can be started and stopped as needed without affecting the three-electric system or cabin temperature control, taking into account both functional expansion and system stability.

[0090] In order to further optimize the implementation effect of the present invention, in some other embodiments, the remaining characteristic technologies are the same, except that the hot and cold temperature control unit 5 includes: a plurality of fan coil units 51 arranged in parallel, and the fan coil units 51 are installed on the top of the vehicle.

[0091] Using this technical solution, in winter mode, heat generated by the heat pump system 1 is delivered simultaneously to the top fan coil unit 51 and the bottom floor radiator 32 via the hot water system 3. The top fan coil unit 51 delivers hot air upward to the passenger compartment, while the bottom floor radiator 32 radiates heat upward, creating a convection cycle of "hot air upwards and heat radiation downwards." This effectively solves the stratification problem of "lower temperatures at the top and higher temperatures at the bottom" caused by traditional single heating methods, improving overall comfort.

[0092] At the same time, the fan coil units 51 arranged in parallel can adjust the air volume in each area through independent valves (such as separate control of the front, middle and rear areas of the passenger compartment). Combined with the top installation position, this ensures that the hot air evenly covers the entire cabin, avoiding local overheating or insufficient heating. Even if one fan coil unit 51 fails, the remaining coils can still operate normally, improving system reliability.

[0093] In order to further optimize the implementation effect of the present invention, in some other embodiments, the other characteristic technologies are the same, except that the heat pump system 1 uses CO2 as the refrigerant, and includes: a CO2 refrigeration compressor, an air cooler 12, a regenerator 13, a drying filter 14, an electronic expansion valve 15, an evaporator 16, and a liquid reservoir 17;

[0094] The CO2 refrigeration compressor, the air cooler 12, the regenerator 13, the drying filter 14, the electronic expansion valve 15, the evaporator 16, and the liquid storage tank 17 are connected through pipelines to form a CO2 refrigerant circulation loop.

[0095] Using this technical solution, CO2 refrigerant has an ODP (ozone depletion potential) of zero and a GWP (global warming potential) far lower than traditional refrigerants, making it more environmentally friendly. CO2 also has high heating efficiency at high pressure, and the air cooler 12 provides a more stable heating capacity.

[0096] The addition of components such as the regenerator 13 and filter drier 14 optimizes the CO2 cycle. The regenerator 13 reduces refrigerant throttling losses, the filter drier 14 prevents moisture from affecting the system, and the electronic expansion valve 15 precisely regulates flow, ensuring stable circulation even in extreme temperatures. This design balances environmental performance with performance, adapting to the complex operating conditions of electric buses.

[0097] In other embodiments, the present invention discloses a multi-mode control method for an electric bus thermal management system, which uses any of the above electric bus thermal management systems to implement thermal management, specifically controlling the operation of the heat pump system 1 according to different seasons.

[0098] In response to the problem of excessive energy consumption caused by the fixed operating mode of the thermal management system in the existing technology and its inability to adapt to seasonal changes, the present invention adopts targeted operating strategies for different seasons to achieve dynamic optimization and adjustment of the system.

[0099] The following is a detailed introduction to the operating mode of each season. Figure 2-5 As shown in the figure, the blue and green pipes are the cooling secondary circuit, the red and yellow pipes are the heating secondary circuit, and the arrows indicate the flow direction of the brine. The dotted line indicates that the pipe is blocked in this mode.

[0100] Further, if Figure 2 As shown, in spring and autumn (e.g., 5°C-25°C), the heat pump system 1 does not work;

[0101] The electronic control and motor ATS cooling unit 8 is connected in series with the battery thermostat 6 through valve switching to form an independent three-electric circulation loop;

[0102] Open the corresponding valve of the cold water system 2 so that the heat generated by the battery, electronic control 81, and motor 82 in the three-electric circulation loop is directly discharged to the outside environment using the ATS heat exchanger 84 under the action of the ATS circulation pump 83.

[0103] The above technical solution adopts the "common mode in spring and autumn: the heat pump system does not work, the battery and electronic control 81 and motor 82 are connected in series, and all the heat generated by the three electrics is discharged to the environment through the ATS heat exchanger 84". It is aimed at the scenarios with suitable ambient temperatures in spring and autumn, and solves the energy waste problem caused by the system relying on heat pump operation throughout the year in the existing technology.

[0104] In this mode, heat pump system 1 completely stops operating, with only the circulating pump of chilled water system 2 driving the refrigerant. This forms a series circuit with the battery, electronic control 81, and motor 82. Waste heat generated by the three-electric system is discharged directly to the outside environment via the ATS heat exchanger 84. Because the temperature difference between the ambient temperature and the waste heat from the three-electric system is relatively small in spring and autumn, natural heat dissipation can meet the temperature control requirements of the three-electric system, eliminating the need to activate the heat pump for cooling or heating, thereby minimizing inefficient energy consumption.

[0105] Compared with the existing design of "maintaining low-load operation of the heat pump regardless of the season", this mode reduces thermal management energy consumption in spring and autumn by simplifying the system operation logic, while reducing the start and stop times of core components such as the heat pump compressor and electronic expansion valve 15, reducing mechanical losses, extending the service life of the system, and achieving efficient and energy-saving operation in mild climates.

[0106] Further, if Figure 3 As shown, in summer (e.g., above 25°C), the heat pump system 1 is started for cooling, and the cooling energy generated by the evaporator 16 is transferred to the chilled water system 2 through the first refrigerant circuit;

[0107] Switch the valves to connect the hot and cold core 4, the hot and cold temperature control unit 5, and the battery thermostat 6 to the first coolant circuit respectively;

[0108] Open the corresponding valves of the cold water system 2, driving the brine under the action of the cold water pump 21 to flow through the parallel cold and hot cores 4, the cold and hot temperature control unit 5, the first bypass branch 91, and then into the parallel battery thermostat 6 and the second bypass branch 92. The flow rate and temperature of the brine flowing through the battery thermostat 6 are regulated by the valve R1 on the first bypass branch 91, the valve R10 on the second bypass branch 92, and the valve R9 on the battery thermostat 6 branch, and the battery thermostat 6 is used to cool the battery.

[0109] The electronic control and motor ATS cooling unit 8 forms an independent circulation loop through valve switching and is not connected to the first coolant loop. The heat of the electronic control 81 and motor 82 is directly discharged to the outside environment through the ATS heat exchanger 84;

[0110] The heat generated by the air cooler 12 is transferred to the hot water system 3 through the second coolant circuit;

[0111] Switch the valve to connect the external heat exchanger 7 to the second refrigerant circuit;

[0112] The corresponding valve of the hot water system 3 is opened to drive the coolant to dissipate heat through the off-vehicle heat exchanger 7 under the action of the hot water pump 31.

[0113] The above technical solution refines the operating logic of the "common summer cooling mode" and optimizes the problem of "interference between the heat dissipation of the three-electric system and the cabin cooling, resulting in insufficient cooling capacity" in high summer temperatures through circuit isolation and cascade cooling design. The specific results are as follows:

[0114] 1) Cascaded utilization of cooling capacity reduces waste. The cooling capacity generated by the evaporator 16 of the heat pump system 1 is transported to the chilled water system 2 via the first refrigerant circuit. The refrigerant then flows through the cockpit cooling and heating core 4 and the passenger compartment fan coil 51. The heated refrigerant then enters the battery thermostat 6. This allows the same cooling capacity to be fully utilized in different temperature demand scenarios, improving cooling capacity utilization.

[0115] 2) Isolating and discharging waste heat to ensure cooling efficiency. The electronic control and motor ATS cooling unit 8 forms an independent circulation system (not connected to the cold water system 2) through valve switching. The high-temperature waste heat generated is directly discharged to the outside of the vehicle through the ATS heat exchanger 84, preventing it from mixing with the cold water system 2 and affecting cooling capacity, ensuring stable cooling of the cabin and batteries.

[0116] 3) Efficient heat removal maintains heat pump performance. The condensation heat generated by the air cooler 12 of the heat pump system 1 is transferred to the hot water system 3 via the second refrigerant circuit. Driven by the hot water pump 31, the refrigerant flows through the off-board heat exchanger 7 to rapidly dissipate the heat, thus preventing excessive condensation pressure and cooling efficiency degradation caused by high summer temperatures.

[0117] 4) Introduce the first bypass branch 91, the second bypass branch 92 and the battery thermostat 6 branch, and coordinately adjust them through the valves of each branch.

[0118] R1 (valve 91 of the first bypass branch) controls the battery inlet water temperature: when the temperature of the coolant is low after being cooled by the cabin, R1 opens to allow some low-temperature coolant that has not been fully heat exchanged to mix directly in, avoiding overcooling of the battery; when the coolant temperature is slightly high, R1 closes to ensure that the coolant temperature entering the battery meets the requirements, so that the battery inlet water temperature is stable.

[0119] R9 (battery thermostat 6 branch valve) and R10 (second bypass branch 92 valve) jointly control the flow: R9 adjusts the total amount of coolant entering the battery thermostat 6, and R10 controls the flow actually involved in cooling by diverting the flow. The two can be dynamically adjusted according to the battery load (for example, when the load is high, R9 opens the diameter and R10 closes the diameter to enhance cooling; vice versa when the load is low), avoiding "excess or insufficient cooling" caused by traditional fixed flow design, ensuring that the battery is always in a safe operating range.

[0120] Further, if Figure 4 As shown, in winter (e.g., below 5°C), the heat pump system 1 is started for heating;

[0121] Switching valves connects the battery thermostat 6 and the off-board heat exchanger 7 to the first coolant circuit respectively;

[0122] The electronic control and motor ATS cooling unit 8 is switched by a valve, does not form an independent circulation loop, is connected to the first coolant loop, and is connected in parallel with the battery thermostat 6 to form a three-electric branch;

[0123] When the temperature of the brine in the first brine loop is lower than the ambient temperature, the corresponding valve of the chilled water system 2 is opened, so that the three-electric branch is connected in series with the off-vehicle heat exchanger 7. The heat generated by the battery, the electronic control 81, and the motor 82 in the three-electric branch, the heat absorbed from the environment by the ATS heat exchanger 84, and the heat absorbed from the environment by the off-vehicle heat exchanger 7 are transferred to the evaporator 16 of the heat pump system 1 through the first brine loop, serving as a low-temperature heat source for the heat pump system 1. Alternatively, when the temperature of the brine in the first brine loop is higher than the ambient temperature, the corresponding valve of the chilled water system 2 is opened, so that the heat generated by the battery, the electronic control 81, and the motor 82 in the three-electric branch is transferred to the evaporator 16 of the heat pump system 1 through the first brine loop, serving as a low-temperature heat source for the heat pump system 1.

[0124] The heat generated by the air cooler 12 is transferred to the hot water system 3 through the second coolant circuit;

[0125] Switch the valves to connect the hot and cold cores 4 and the hot and cold temperature control units 5 to the second refrigerant circuit respectively;

[0126] The corresponding valve of the hot water system 3 is opened, and the coolant is driven to flow through the parallel hot and cold cores 4, the hot and cold temperature control units 5 and the floor radiator 32 under the action of the hot water pump 31.

[0127] The above technical solution is adopted, through the coordination of waste heat recovery of three-electricity and heat pump heating, to solve the problem of existing technology "winter heating relies on PTC, high energy consumption and uneven temperature in the cabin", and adapt to the efficient operation requirements in cold environment.

[0128] From an energy utilization perspective, in winter mode, the system switches valves to connect the electronic control and motor ATS cooling unit 8 to the cold water system 2, and connects it in parallel with the battery thermostat 6 to form a three-electric branch. When the refrigerant temperature is lower than the ambient temperature, the three-electric branch is connected in series with the external heat exchanger 7, recovering the waste heat from the three electric units and absorbing heat from the environment through the ATS heat exchanger 84 and the external heat exchanger 7. Together, these two branches serve as a low-temperature heat source for the heat pump evaporator 16, raising the evaporation temperature and heating capacity. When the refrigerant temperature is higher than the ambient temperature, the waste heat from the three electric units is directly used to power the heat pump. This design significantly reduces reliance on high-energy-consuming PTC heating, significantly reducing heating energy consumption and extending the range of electric vehicles.

[0129] If the waste heat from the three electric systems is very low or even nonexistent (such as when the vehicle is just started), the brine temperature exiting evaporator 16 is lower than the ambient temperature. In this case, the brine needs to absorb heat from the environment. Specifically, whether this absorption is necessary is determined by the brine temperature after valve H5. If the brine temperature is lower than the ambient temperature at this point, the brine flows to the off-board heat exchanger 7. Otherwise, the brine does not flow to the off-board heat exchanger 7.

[0130] From the perspective of comfort, the heat generated by the air cooler 12 is transported through the hot water system 3 to the parallel hot and cold core 4 (cockpit), the hot and cold temperature control unit 5 (the fan coil 51 on the top of the passenger compartment) and the floor radiator 32 (the bottom of the passenger compartment), forming a "top blowing + bottom radiation" heating combination, effectively solving the "cold on top and hot on bottom" problem caused by a single heating method in winter, and improving riding comfort.

[0131] Further, if Figure 5 As shown, in the case of parking charging in severe winter (e.g., below -25°C), the heat pump system 1 is started for heating;

[0132] Switch the valve to connect the external heat exchanger 7 to the first refrigerant circuit;

[0133] The electronic control and motor ATS cooling unit 8 is switched by a valve, does not form an independent circulation loop, and is connected to the first coolant loop;

[0134] When the temperature of the brine in the first brine loop is lower than the ambient temperature, the corresponding valve of the chilled water system 2 is opened, so that the electronic control and motor ATS cooling unit 8 is connected in series with the external heat exchanger 7, and the heat generated by the electronic control 81 and the motor 82, the heat absorbed from the environment by the ATS heat exchanger 84, and the heat absorbed from the environment by the external heat exchanger 7 are transferred to the evaporator 16 of the heat pump system 1 through the first brine loop, serving as a low-temperature heat source for the heat pump system 1; or, when the temperature of the brine in the first brine loop is higher than the ambient temperature, the corresponding valve of the chilled water system 2 is opened, so that the heat generated by the electronic control 81 and the motor 82 is transferred to the evaporator 16 of the heat pump system 1 through the first brine loop, serving as a low-temperature heat source for the heat pump system 1;

[0135] Switch the valve to connect the battery thermostat 6 to the second coolant circuit;

[0136] The heat generated by the air cooler 12 is transferred to the hot water system 3 through the second coolant circuit;

[0137] The corresponding valve of the hot water system 3 is opened to drive the coolant to flow through the battery thermostat 6 under the action of the hot water pump 31 .

[0138] By adopting the above technical solution, the system introduces a heat pump system 1 to address the defects of the existing technology of "low battery heating efficiency and poor system adaptability in severe cold environments below -25°C". In severe winter, heat can be directly transferred to the battery thermostat 6 to heat the battery.

[0139] Heat pump system 1 heats the battery. Heat generated by air cooler 12 is directly transferred to battery thermostat 6 via a second refrigerant circuit, achieving targeted heating. Compared to traditional PTC electric heating, heat pump system 1 offers a higher coefficient of performance (COP) at -25°C and faster heating speeds, ensuring the battery quickly reaches its optimal operating temperature in extremely cold environments, preventing capacity loss and battery life loss caused by low temperatures.

[0140] When the refrigerant temperature in the first refrigerant circuit is lower than the ambient temperature, the heat generated by the air cooler 12 directly enters the inlet of the battery thermostat 6 through valve R5 to heat the battery; at the same time, the refrigerant flowing out of the evaporator 16 enters the ATS heat exchanger 84 and the external heat exchanger 7 through valves R1 and R8, absorbing low-grade thermal energy from the extremely low temperature environment to supplement the cooling capacity demand of the evaporator 16.

[0141] Furthermore, the system uses dotted lines (no flow) to cut off non-essential circuits, reducing heat loss and concentrating heat on battery heating, thus avoiding energy dissipation. This design is particularly important in parking and charging scenarios, as it ensures battery activity without draining the onboard battery (which can rely on charging stations for power). This addresses the pain point of electric buses in cold regions, where batteries can lose temperature after parking, leading to a sharp drop in range upon the next start.

[0142] The present invention discloses a thermal management system and a multi-mode control method for an electric bus, which have the following beneficial effects:

[0143] First, efficient energy transfer is achieved through the integrated linkage of heat pumps, cold water, and hot water systems, combined with the design of a secondary heat exchange circuit.

[0144] Second, during summer cooling, the low-temperature refrigerant from the evaporator first flows through the cockpit heating and cooling core and the passenger compartment heating and cooling units to meet cabin cooling requirements. The heated refrigerant then enters the battery thermostat to cool the batteries. This not only ensures that the refrigerant temperature entering the batteries meets the required cooling requirements, but also fully utilizes the cooling capacity, reduces inefficient consumption, and achieves cascaded energy utilization and efficient synergy, significantly reducing energy consumption and extending battery life.

[0145] Third, in winter, the heat pump unit uses three-electric heat recovery technology to use the cold energy generated by the evaporator to cool the three electrics (battery, motor, and electronic control), and uses the heat generated by the air cooler to heat the vehicle cabin (cockpit and passenger compartment). Not only are the cold and heat energy of the heat pump unit fully utilized at the same time, the comprehensive energy efficiency coefficient of the heat pump is increased by more than 1 times, and the problem of poor performance of the heat pump or even inability to work normally in cold weather is solved.

[0146] Fourth, in spring and autumn, the battery and the electronically controlled motor are connected in series, and all the heat generated by the three electrics is discharged to the environment through the ATS heat exchanger. The environment is used to cool the battery, and the heat pump system does not need to work, which significantly reduces energy consumption.

[0147] Fifth, through multi-loop design and valve switching logic, precise adaptation to changes in cold and hot loads and extreme climates in different seasons and working conditions is achieved, solving the problem of weak environmental adaptability of traditional systems.

[0148] Sixth, on the basis of meeting core thermal management requirements, the vehicle's functional richness and riding experience are enhanced through component integration and collaborative control.

[0149] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which shall fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. Electric bus thermal management system, characterized in that: include: A heat pump system, a chilled water system, and a hot water system. The heat pump system includes a compressor, an air cooler, an evaporator, and a refrigerant circulation loop connecting the various components. The heat pump system is connected to the chilled water system via the evaporator, and the heat pump system is connected to the hot water system via the air cooler. The cold water system includes: a cold water pump and a first coolant circuit connecting various components; The hot water system includes: a hot water pump, a floor radiator and a second coolant circuit connecting various components, wherein the floor radiator is used to heat the passenger compartment; The electric bus thermal management system further includes: a hot and cold core, a hot and cold temperature regulating unit, a battery thermostat, and an off-board heat exchanger, wherein the hot and cold core, the hot and cold temperature regulating unit, the battery thermostat, and the off-board heat exchanger are selectively connected to the first coolant circuit or the second coolant circuit through valve switching. The hot and cold core is used to adjust the temperature of the cockpit, and the hot and cold temperature regulating unit is used to adjust the temperature of the passenger compartment; The battery thermostat is used to regulate the battery temperature. When the cold water system is operating in a cooling mode, the battery thermostat is disposed downstream of the hot and cold core and the hot and cold temperature regulating unit, so that the cold in the first refrigerant circuit flows through the hot and cold core and the hot and cold temperature regulating unit before entering the battery thermostat to cool the battery. The off-vehicle heat exchanger is used to discharge the heat generated by the hot water system to the outside environment, or absorb heat from the outside environment and transfer it to the cold water system; The electric bus thermal management system further includes: an electric control and motor ATS cooling unit, which can be selectively connected to the first coolant circuit through valve switching to achieve heat exchange with the coolant of the cold water system, and / or form an independent circulation pipeline to use its own ATS heat exchanger to directly discharge heat to the external environment of the vehicle. The electric control and motor ATS cooling unit is used to dissipate heat for the electric control and motor; The cooling energy generated by the evaporator of the heat pump system is transferred to the chilled water system through the first refrigerant circuit to form a secondary cooling energy circuit; The heat generated by the air cooler of the heat pump system is transferred to the hot water system through the second refrigerant circuit to form a secondary heat circuit; The cooling secondary circuit and the heating secondary circuit work independently to realize the distribution of cooling and heating respectively.

2. The electric bus thermal management system according to claim 1, characterized in that: The electronic control and motor ATS cooling unit includes: electronic control, motor, ATS circulation pump and ATS heat exchanger.

3. The electric bus thermal management system according to claim 1, characterized in that: The cold water system further comprises: a refrigerator, wherein the refrigerator is used to refrigerate items; The hot water system further comprises a high temperature cabinet, which is used for heating items.

4. The electric bus thermal management system according to claim 1, characterized in that: The cooling and heating temperature control unit includes: a plurality of fan coil units arranged in parallel, and the fan coil units are installed on the top of the vehicle.

5. The electric bus thermal management system according to claim 1, characterized in that: The heat pump system uses CO2 as refrigerant, and the heat pump system includes: a CO2 refrigeration compressor, an air cooler, a regenerator, a drying filter, an electronic expansion valve, an evaporator, and a liquid receiver; The CO2 refrigeration compressor, air cooler, regenerator, drying filter, electronic expansion valve, evaporator and liquid storage are connected through pipelines to form a CO2 refrigerant circulation loop.

6. A multi-mode control method for a thermal management system of an electric bus, characterized in that: Thermal management is achieved by utilizing the thermal management system for an electric bus as described in any one of claims 1 to 5, specifically controlling the operation of the heat pump system according to different seasons.

7. The multi-mode operation method according to claim 6, characterized in that: In spring and fall, the heat pump system does not work; The electronic control and motor ATS cooling units are switched via valves and connected in series with the battery thermostat to form an independent three-electric circulation loop. Open the corresponding valve of the cold water system so that the heat generated by the battery, electronic control and motor in the three-electric circulation loop can be directly discharged to the outside environment using the ATS heat exchanger under the action of the ATS circulation pump.

8. The multi-mode operation method according to claim 6, characterized in that: In summer, the heat pump system is started for cooling, and the cooling capacity generated by the evaporator is transferred to the chilled water system through the first refrigerant loop; Switching valves connect the hot and cold cores, the hot and cold temperature control units, and the battery thermostat to the first coolant circuit respectively; Open the corresponding valve of the cold water system, driving the brine coolant under the action of the cold water pump to flow through the parallel hot and cold cores, the hot and cold temperature control units, the first bypass branch, and then into the parallel battery thermostat and the second bypass branch. The flow rate and temperature of the brine coolant flowing through the battery thermostat are adjusted by the valves on the first bypass branch, the second bypass branch, and the battery thermostat branch, and the battery thermostat is used to cool the battery; The electronic control and motor ATS cooling units are switched by valves to form independent circulation loops that are not connected to the primary coolant loop. The heat from the electronic control and motor is discharged directly to the outside environment using the ATS heat exchanger. The heat generated by the air cooler is transferred to the hot water system through the second refrigerant circuit; Switching the valve to connect the off-board heat exchanger to the second refrigerant circuit; Open the corresponding valve of the hot water system and drive the coolant to dissipate heat through the external heat exchanger under the action of the hot water pump.

9. The multi-mode operation method according to claim 6, characterized in that: In winter, start the heat pump system for heating; Switching valves to connect the battery thermostat and the off-vehicle heat exchanger to the first coolant circuit respectively; The electronic control and motor ATS cooling units are switched through valves, not forming an independent circulation loop, but connected to the first coolant loop and connected in parallel with the battery thermostat to form a three-electric branch. When the temperature of the refrigerant in the first refrigerant circuit is lower than the ambient temperature, the corresponding valve of the cold water system is opened, so that the three-electric branch is connected in series with the off-vehicle heat exchanger. The heat generated by the battery, electronic control, and motor in the three-electric branch, the heat absorbed from the environment by the ATS heat exchanger, and the heat absorbed from the environment by the off-vehicle heat exchanger are transferred to the evaporator of the heat pump system through the first refrigerant circuit, serving as a low-temperature heat source for the heat pump system. Alternatively, when the temperature of the refrigerant in the first refrigerant circuit is higher than the ambient temperature, the corresponding valve of the cold water system is opened, so that the heat generated by the battery, electronic control, and motor in the three-electric branch is transferred to the evaporator of the heat pump system through the first refrigerant circuit, serving as a low-temperature heat source for the heat pump system. The heat generated by the air cooler is transferred to the hot water system through the second refrigerant circuit; Switching valves connect the hot and cold cores and the hot and cold temperature control units to the second refrigerant circuit respectively; Open the corresponding valve of the hot water system to drive the coolant to flow through the parallel hot and cold cores, hot and cold temperature control units and floor radiators under the action of the hot water pump.

10. The multi-mode operation method according to claim 6, characterized in that: During parking and charging in severe winter, the heat pump system is activated for heating; Switching the valve to connect the off-board heat exchanger to the first refrigerant circuit; The electronic control and motor ATS cooling units are switched through valves and do not form independent circulation loops, but are connected to the first coolant loop; When the temperature of the brine in the first brine loop is lower than the ambient temperature, the corresponding valve of the chilled water system is opened, so that the electronic control and motor ATS cooling unit is connected in series with the off-vehicle heat exchanger, and the heat generated by the electronic control and motor, the heat absorbed from the environment by the ATS heat exchanger, and the heat absorbed from the environment by the off-vehicle heat exchanger are transferred to the evaporator of the heat pump system through the first brine loop, serving as a low-temperature heat source for the heat pump system; or, when the temperature of the brine in the first brine loop is higher than the ambient temperature, the corresponding valve of the chilled water system is opened, so that the heat generated by the electronic control and motor is transferred to the evaporator of the heat pump system through the first brine loop, serving as a low-temperature heat source for the heat pump system; Switching the valve to connect the battery thermostat to the second coolant circuit; The heat generated by the air cooler is transferred to the hot water system through the second refrigerant circuit; Open the corresponding valve of the hot water system and drive the coolant to flow through the battery thermostat under the action of the hot water pump.

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