Thermal management system with electric drive waste heat utilization and waste heat utilization control method

Abstract

A heat circulation system of a vehicle comprises a heat pump system, a battery system and an electric drive system, an output port of the heat pump system is connected with an input port of the electric drive system, an output port of the electric drive system is connected with an input port of a one-inlet two-outlet three-way valve, and an output port of the one-inlet two-outlet three-way valve is connected with an output port of the battery system. One output port of the one-inlet and two-outlet three-way valve is connected with an input port of the heat pump system and an input port of the battery system through a tee joint, and the other output port of the one-inlet and two-outlet three-way valve and an output port of the battery system are connected with two input ports of the two-inlet and one-outlet three-way valve. And an output port of the two-inlet and one-outlet three-way valve is connected with an input port of the electric drive system. According to the method, a joint simulation model based on a whole vehicle transmission system model, a thermal management thermal model and a control strategy model is combined and associated with a use scene, DOE multi-parameter setting is carried out on a plurality of temperature set thresholds, optimization analysis of transmission system energy loss, thermal management accessory energy consumption, battery energy loss and the like is carried out, and the control strategy model is established. And finally, according to an energy consumption optimization principle, a temperature setting threshold value is determined, and real-time regulation and control are performed.

Description

Technical Field

[0001] The present invention relates to the field of automobiles (including pure electric vehicles), and in particular to a thermal management system with electric drive waste heat utilization and a waste heat utilization control method. Background Art

[0002] With the widespread popularity of electric vehicles, the low-temperature endurance of electric vehicles has become one of the core pain points for customers. Reducing the low-temperature energy consumption of the entire vehicle and increasing the battery discharge energy have become top priorities. The heating heat source for vehicles in winter mainly comes from PTC electric heaters and heat pump systems, part of which comes from waste heat (waste heat) generated by electric drive. For example, the public document with publication number CN110254175A, publication date September 20, 2019, and patent name "A waste heat recovery heat pump thermal management device for new energy vehicles" discloses a waste heat recovery heat pump thermal management device including an electric compressor, one end of the electric compressor is connected to one end of a first three-way valve, the other end of the electric compressor is connected to a gas-liquid separator, and the other end of the first three-way valve is connected to one end of an outdoor heat exchanger. An evaporator and a plate heat exchanger are arranged in parallel between the outdoor heat exchanger and the gas-liquid separator, the evaporator is connected in series with a thermal expansion valve and a third two-way valve, and the plate heat exchanger is connected in series with a first electronic expansion valve; a second electronic expansion valve and a first two-way valve are arranged in parallel on the pipeline between the outdoor heat exchanger and the first electronic expansion valve.

[0003] The utilization of this energy in real cars is rather subjective, and it is difficult to optimize the utilization of waste heat. Specifically, if the waste heat is used for battery heating or heat pump heating too early, the temperature of the electric drive itself will be low and its own loss will be too large. If it is always in the state of self-heat storage, it will lead to energy waste and relatively low battery temperature, resulting in increased battery loss and reduced battery discharge, which is generally contrary to expectations. Summary of the invention

[0004] The technical problem to be solved by the present invention is to realize a control system and method for utilizing waste heat of electric drive, combine the joint simulation model based on the vehicle transmission system model, thermal management thermal model and control strategy model, associate the usage scenarios, and optimize the real-time transmission system energy loss, thermal management accessory energy consumption and battery energy loss.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a thermal management system with electric drive waste heat utilization, the vehicle's thermal circulation system includes a heat pump system, a battery system and an electric drive system, the output port of the heat pump system is connected to the input port of the electric drive system, the output port of the electric drive system is connected to the input port of a one-input and two-outlet three-way valve, one output port of the one-input and two-outlet three-way valve is connected to the input port of the heat pump system and the input port of the battery system through a three-way valve, the other output port of the one-input and two-outlet three-way valve and the output port of the battery system are connected to the two input ports of the two-input and one-outlet three-way valve, and the output port of the two-input and one-outlet three-way valve is connected to the input port of the electric drive system.

[0006] The output port of the two-inlet-one-outlet three-way valve is connected to the pipeline between the heat pump system and the electric drive system through the three-way valve. The heat pump system, battery system, electric drive system, one-inlet-two-outlet three-way valve and two-inlet-one-out three-way valve are coordinated and controlled by the vehicle control unit, thermal management unit and electric drive control unit.

[0007] The electric drive system, the one-inlet and two-outlet three-way valve and the two-inlet and one-outlet three-way valve form a circulation loop, forming the electric drive's own hot water storage loop;

[0008] The battery system, a one-inlet and two-outlet three-way valve, an electric drive system, and a two-inlet and one-outlet three-way valve form a circulation loop, forming a battery heating water loop;

[0009] The heat pump system, the electric drive system, and the one-inlet and two-outlet three-way valve form a circulation loop, forming a heat pump heating water loop.

[0010] A waste heat utilization control method of a thermal management system with electric drive waste heat utilization:

[0011] The initial state executes the electric drive's own hot water storage circuit;

[0012] When condition 1 is met, the battery heating water circuit is executed;

[0013] The condition 1 is that the water path temperature Tm of the electric drive system exceeds the temperature setting threshold A, and the battery temperature Tb is less than the temperature setting threshold B.

[0014] When executing the battery heating water circuit, if condition 2 is met, the electric drive's own hot water storage circuit is executed;

[0015] The condition 2: the difference between Tm and Tb is less than the temperature setting threshold D.

[0016] If the battery temperature continues to rise, the temperature of the electric drive water circuit gradually decreases until condition 2 is met, and the electric drive switches to its own heat storage state and no longer heats the battery. When condition 1 is met again, the battery is heated again, or when condition 3 is met, the heat pump system is heated. Figure 6 At this time, the temperature of the electric drive water circuit gradually decreases until condition 4 is met, and the electric drive switches to its own heat storage state.

[0017] When condition 3 is met, the heat pump heats the water circuit;

[0018] The condition 3 is: the electric drive water circuit temperature Tm exceeds the temperature setting threshold C, and the battery temperature Tb is greater than the temperature setting threshold B.

[0019] 8. The waste heat utilization control method with electric drive waste heat utilization according to claim 7, when executing the heat pump heating water circuit, if condition 4 is met, the electric drive's own hot water storage circuit is executed;

[0020] The condition 4: Tm is less than the set temperature threshold E.

[0021] A joint simulation model based on the vehicle powertrain model, thermal management model and control strategy model is established. Based on the joint simulation model, DOE multi-parameter setting of the set temperature threshold is performed. Following the principle of energy consumption optimization, the set temperature threshold A, set temperature threshold B, set temperature threshold C, set temperature threshold D and set temperature threshold E are obtained respectively.

[0022] The control system and method for utilizing waste heat from electric drives of the present invention are based on a joint simulation model that combines a vehicle powertrain model, a thermal management model, and a control strategy model, and is associated with usage scenarios. DOE multi-parameter settings are performed on multiple temperature setting thresholds, and optimization analysis of powertrain energy loss, thermal management accessory energy consumption, and battery energy loss are performed. Finally, the temperature setting threshold is determined in accordance with the principle of energy consumption optimization, and real-time regulation is performed. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The following is a brief description of the contents expressed in each figure in the specification of the present invention:

[0024] Figure 1 It is a schematic diagram of the joint imitation model of the present invention;

[0025] Figure 2 This is a schematic diagram of a control method for utilizing waste heat from electric drive according to the present invention;

[0026] Figure 3 This is a schematic diagram of a water circuit for utilizing waste heat from electric drive in a thermal management system according to the present invention;

[0027] Figure 4 This is a schematic diagram of the electric drive waste heat utilization - electric drive own hot water storage circuit of the present invention;

[0028] Figure 5 This is a schematic diagram of the electric drive waste heat utilization-battery heating water circuit of the present invention;

[0029] Figure 6 This is a schematic diagram of the electric drive waste heat utilization-heat pump water heating circuit of the present invention. DETAILED DESCRIPTION

[0030] The following is a further detailed description of the specific implementation methods of the present invention, such as the shape, structure, relative position and connection relationship between the various components involved, the function and working principle of each part, the manufacturing process and operation method, etc., through the description of the embodiments with reference to the accompanying drawings, so as to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention.

[0031] The present invention is a control system and method for utilizing waste heat from electric drives. The joint simulation model is based on a vehicle powertrain model, a thermal management model, and a control strategy model, and is associated with usage scenarios. DOE multi-parameter settings are performed on multiple temperature setting thresholds, and optimization analysis of powertrain energy loss, thermal management accessory energy consumption, and battery energy loss are performed. Finally, the temperature setting threshold is determined in accordance with the energy consumption optimization principle, and real-time regulation is performed.

[0032] like Figure 3 As shown in the schematic diagram of the water circuit for utilizing waste heat from the electric drive of the thermal management system, the thermal management system with waste heat utilization of the electric drive, the thermal circulation system of the vehicle forms a new circulation circuit based on the existing heat pump system, battery system and thermal circulation system of the electric drive system, in which two electronically controlled valves are added for coordinated control, and the two electronically controlled valves are a one-inlet and two-outlet three-way valve and a two-inlet and one-outlet three-way valve respectively, and the thermal circulation systems of the heat pump system, the battery system and the electric drive system are all provided with an input port (water inlet) and an output port (water outlet).

[0033] The connection method is as follows:

[0034] One output port of the one-inlet and two-outlet three-way valve is connected to the heat pump system and the heat circulation system input port (water inlet) of the battery system respectively. Since the input ports of the two systems are connected at the same time, they can be connected through a three-way connection, that is, the three outlets of the three-way connection are connected to the heat pump system, the heat circulation system input port (water inlet) of the battery system, and one output port of the one-inlet and two-outlet three-way valve respectively through pipelines;

[0035] The other output port of the one-input-two-outlet three-way valve is connected to one input port of the two-input-one-outlet three-way valve through a pipeline, the thermal circulation system output port (water outlet) of the battery system is connected to the other input port of the two-input-one-outlet three-way valve, and the thermal circulation system output port (water outlet) of the electric drive system is connected to the input port of the one-input-two-outlet three-way valve through a pipeline;

[0036] The heat circulation system input port (water inlet) of the electric drive system is connected to the output port of the two-inlet and one-outlet three-way valve and the heat circulation system output port (water outlet) of the heat pump system through pipelines. Therefore, it can be connected through a three-way connection, that is, the three outlets of the three-way connection are connected to the heat circulation system output port (water outlet) of the heat pump system, the output port of the two-inlet and one-outlet three-way valve, and the heat circulation system input port (water inlet) of the electric drive system through pipelines.

[0037] The one-inlet-two-outlet three-way valve is electrically controlled to connect one of the output ports with the input port, and the two-inlet-one-outlet three-way valve is electrically controlled to connect one of the input ports with the output port. The specific selection needs to be coordinated and controlled according to the preset control logic.

[0038] When the one-in-two-out three-way valve controls the electric drive system to be connected with the two-in-one-out three-way valve, and the two-in-one-out three-way valve controls the one-in-two-out three-way valve to be connected with the electric drive system, the electric drive system, the one-in-two-out three-way valve and the two-in-one-out three-way valve form a circulation loop, forming the electric drive's own hot water storage loop. Figure 4 As shown, the coolant flowing out of the electric drive system flows back to the electric drive system through the one-in-two-out three-way valve and the two-in-one-out three-way valve, forming a complete circulation loop;

[0039] When the one-in-two-out three-way valve controls the battery system and the electric drive system to be connected, and the two-in-one-out three-way valve controls the battery system and the electric drive system to be connected, the battery system, the one-in-two-out three-way valve, the electric drive system, and the two-in-one-out three-way valve form a circulation loop, forming a battery heating water loop. Figure 5 As shown, the coolant flowing out of the electric drive system flows to the battery system through a one-in-two-out three-way valve, and the coolant flowing out of the battery system flows to the electric drive system through a two-in-one-out three-way valve, forming a complete circulation loop;

[0040] When the one-in-two-out three-way valve controls the heat pump system and the electric drive system to be connected, the two-in-one-out three-way valve does not enter the circulation. The heat pump system, the electric drive system, and the one-in-two-out three-way valve form a circulation loop, forming a heat pump heating water loop. Figure 6 As shown, the coolant flowing out of the electric drive system flows to the heat pump system through a one-inlet and two-outlet three-way valve, and the coolant flowing out of the heat pump system flows back to the electric drive system, forming a complete circulation loop.

[0041] Based on the above thermal management system with electric drive waste heat utilization, the control method of electric drive waste heat utilization is a joint simulation model based on the vehicle powertrain model, thermal management model and control strategy model, which is associated with the usage scenario to optimize the real-time powertrain energy loss, thermal management accessory energy consumption and battery energy loss. The hardware parts required are the vehicle control unit, thermal management unit and electric drive control unit.

[0042] The vehicle control unit reads basic signal information: vehicle speed, ambient temperature, passenger compartment temperature, etc.

[0043] The thermal management unit reads basic signal information: battery water inlet temperature, etc.

[0044] The electric drive control unit reads basic signal information: electric drive stator temperature, etc.

[0045] Associated usage scenarios (as analysis boundaries and target inputs), read basic signal information through the vehicle control unit, thermal management unit and electric drive control unit: vehicle speed, ambient temperature, passenger compartment temperature, electric drive water inlet temperature, electric drive stator temperature, battery water inlet temperature and other vehicle and thermal management signals. Figure 1 As shown in the figure, in the established joint simulation model, the vehicle control unit serves as the control core of the system, and is connected and outputs drive signals to the one-input and two-outlet three-way valve and the two-input and one-outlet three-way valve at the same time. The thermal management unit is connected and coordinates the control of the heat pump system and the battery system. The electric drive control unit is connected and coordinates the control of the electric drive system. The vehicle control unit obtains the information of the thermal management unit and the electric drive control unit through the CAN network, and performs overall coordinated control. By controlling the one-input and two-outlet three-way valve and the two-input and one-out three-way valve, the waste heat of the electric drive of the thermal management system is utilized.

[0046] The joint simulation model is established by obtaining the ambient temperature, passenger compartment temperature, passenger compartment target temperature, vehicle speed, slope, etc. in real time through signals, and inputting the obtained data information into the transmission system physical model and thermal management physical model respectively. The transmission system physical model and thermal management physical model are data models pre-designed for each vehicle model, which are used to obtain relevant theoretical data. The collected signals are based on the transmission system physical model to obtain the required power of the whole vehicle, and the collected signals are based on the thermal management physical model to obtain the power consumption of thermal management accessories;

[0047] The power required by the vehicle includes: electric drive physical model, battery physical model, battery physical model

[0048] Based on settings:

[0049] Threshold A1 / A2...

[0050] Threshold C1 / C2……

[0051] Threshold D1 / D2...

[0052] The electric drive physical model is obtained: the electric drive system energy loss Q1 / Q2...

[0053] Battery physical model obtains: battery system energy loss W1 / W2……

[0054] Battery physical model acquisition: battery system discharge capacity E1 / E2……

[0055] The thermal management accessory power consumption is based on the threshold value B1 / B2... to obtain the thermal management system energy loss P1 / P2...

[0056] Because this system uses real-time vehicle data to obtain current vehicle status information, the vehicle's required power and the power consumption of thermal management accessories change with the vehicle's status, making the thermal management system's electric drive waste heat utilization more reliable and reasonable.

[0057] Finally, based on the energy loss of the electric drive system, the energy loss of the battery system, the discharge of the battery system, and the energy loss of the thermal management system, we optimize Q+W+P+E, determine the A / B / C thresholds, and perform DOE multi-parameter settings for the temperature setting thresholds A / B / C / D / E. We also perform optimization analysis on the energy loss of the powertrain, the energy consumption of thermal management accessories, and the energy loss of the battery;

[0058] Follow the principle of energy consumption optimization, that is, find the best value among Q+W+P+E, and determine the corresponding temperature setting threshold values ​​A / B / C / D / E;

[0059] Then, according to the control strategy logic, the initial state is that the electric drive stores heat by itself. If the electric drive water circuit temperature Tm exceeds the temperature setting threshold A, and the battery temperature Tb is less than the temperature setting threshold B, the electric drive waste heat is used to heat the battery. When the heating capacity is small, that is, the difference between Tm and Tb is less than the temperature setting threshold D, the battery heating is exited and the electric drive enters the self-heat storage state. If the electric drive heating capacity is sufficient and the battery does not need to be heated, that is, the electric drive water circuit temperature Tm exceeds the temperature setting threshold C, and the battery temperature Tb is greater than the temperature setting threshold B, the electric drive waste heat is used to heat the heat pump. When the electric drive temperature is low, that is, Tm is less than the set temperature threshold E, the heat pump heating is exited and the electric drive enters the self-heat storage state.

[0060] Secondly, in association with the usage scenarios, basic signal information is read through the vehicle control unit, thermal management unit and electric drive control unit: vehicle speed, ambient temperature, passenger compartment temperature, electric drive water inlet temperature, electric drive stator temperature, battery water inlet temperature and other vehicle and thermal management signals; based on the established joint simulation model, DOE multi-parameter setting of the temperature setting thresholds A / B / C / D / E is performed, and optimization analysis of transmission system energy loss, thermal management accessory energy consumption and battery energy loss is performed.

[0061] The specific strategy logic is as follows:

[0062] In the initial state, that is, when the vehicle is started, the electric drive's own hot water storage circuit is executed;

[0063] Set the following conditions:

[0064] Condition 1: If the electric drive water circuit temperature Tm exceeds the temperature setting threshold A, and the battery temperature Tb is less than the temperature setting threshold B, the electric drive waste heat is used to heat the battery;

[0065] Condition 2: When the heating capacity is small, that is, when the difference between Tm and Tb is less than the temperature setting threshold D, the battery heating is exited and the electric drive enters the self-heat storage state;

[0066] Condition 3: If the electric drive heating capacity is sufficient and the battery does not need to be heated, that is, the electric drive water path temperature Tm exceeds the temperature setting threshold C, and the battery temperature Tb is greater than the temperature setting threshold B, the electric drive waste heat is used to heat the heat pump;

[0067] Condition 4: When the temperature of the electric drive is low, that is, when Tm is less than the set temperature threshold E, the heat pump heating is exited and the electric drive enters its own heat storage state;

[0068] When condition 1 is met, the electric drive water circuit is switched to the battery heating water circuit. Figure 5 As shown, the battery temperature continues to rise, and the temperature of the electric drive water circuit gradually decreases;

[0069] When condition 2 is met, the electric drive switches to its own hot water storage circuit and no longer heats the battery. When condition 1 is met again, the battery is heated again.

[0070] When condition 3 is met, the heat pump system is heated and the electric drive is switched to the heat pump heating water circuit. Figure 6 , at this time, the temperature of the electric drive water circuit gradually decreases;

[0071] In the heat pump heating water circuit state, when condition 4 is met, the electric drive switches to the electric drive's own hot water storage circuit.

[0072] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A thermal management system with electric drive waste heat utilization, the thermal circulation system of the vehicle includes a heat pump system, a battery system and an electric drive system, characterized in that: The output port of the heat pump system is connected to the input port of the electric drive system, the output port of the electric drive system is connected to the input port of a one-input and two-outlet three-way valve, one output port of the one-input and two-outlet three-way valve is connected to the input port of the heat pump system and the input port of the battery system via a three-way valve, the other output port of the one-input and two-outlet three-way valve and the output port of the battery system are connected to the two input ports of the two-input and one-outlet three-way valve, and the output port of the two-input and one-outlet three-way valve is connected to the input port of the electric drive system.

2. The thermal management system with electric drive waste heat utilization according to claim 1 is characterized in that: The output port of the two-inlet-one-outlet three-way valve is connected to the pipeline between the heat pump system and the electric drive system through the three-way valve. The heat pump system, battery system, electric drive system, one-inlet-two-outlet three-way valve and two-inlet-one-out three-way valve are coordinated and controlled by the vehicle control unit, thermal management unit and electric drive control unit.

3. The thermal management system with electric drive waste heat utilization according to claim 2 is characterized in that: The electric drive system, the one-inlet and two-outlet three-way valve and the two-inlet and one-outlet three-way valve form a circulation loop, forming the electric drive's own hot water storage loop; The battery system, a one-inlet and two-outlet three-way valve, an electric drive system, and a two-inlet and one-outlet three-way valve form a circulation loop, forming a battery heating water loop; The heat pump system, the electric drive system, and the one-inlet and two-outlet three-way valve form a circulation loop, forming a heat pump heating water loop.

4. A waste heat utilization control method of a thermal management system with electric drive waste heat utilization, characterized in that: The initial state executes the electric drive's own hot water storage circuit; When condition 1 is met, the battery heating water circuit is executed; The condition 1 is that the water path temperature Tm of the electric drive system exceeds the temperature setting threshold A, and the battery temperature Tb is less than the temperature setting threshold B.

5. The waste heat utilization control method with electric drive waste heat utilization according to claim 4 is characterized in that: When executing the battery heating water circuit, if condition 2 is met, the electric drive's own hot water storage circuit is executed; The condition 2: the difference between Tm and Tb is less than the temperature setting threshold D.

6. The waste heat utilization control method with electric drive waste heat utilization according to claim 5, characterized in that: If the battery temperature continues to rise, the temperature of the electric drive water circuit gradually decreases until condition 2 is met, and the electric drive switches to its own heat storage state and no longer heats the battery. When condition 1 is met again, the battery is heated again, or when condition 3 is met, the heat pump system is heated, as shown in Figure 6. At this time, the temperature of the electric drive water circuit gradually decreases until condition 4 is met, and the electric drive switches to its own heat storage state.

7. The waste heat utilization control method with electric drive waste heat utilization according to claim 6, characterized in that: When condition 3 is met, the heat pump heats the water circuit; The condition 3 is: the electric drive water circuit temperature Tm exceeds the temperature setting threshold C, and the battery temperature Tb is greater than the temperature setting threshold B.

8. The waste heat utilization control method with electric drive waste heat utilization according to claim 7, characterized in that: When executing the heat pump heating water circuit, if condition 4 is met, the electric drive's own hot water storage circuit will be executed; The condition 4: Tm is less than the set temperature threshold E.

9. The waste heat utilization control method with electric drive waste heat utilization according to claim 8, characterized in that: A joint simulation model based on the vehicle powertrain model, thermal management model and control strategy model is established. Based on the joint simulation model, DOE multi-parameter setting of the set temperature threshold is performed. Following the principle of energy consumption optimization, the set temperature threshold A, set temperature threshold B, set temperature threshold C, set temperature threshold D and set temperature threshold E are obtained respectively.

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