Heat recovery system and control method thereof, vehicle

Abstract

This application discloses a waste heat recovery system, its control method, and a vehicle. The waste heat recovery system includes a waste heat recovery unit, an exhaust pipe, a third control valve, a fourth control valve, a first temperature and pressure sensor, and a controller. By installing a first temperature and pressure sensor at the outlet end of the heat exchange medium flow channel of the waste heat recovery unit, the temperature and pressure of the heat exchange medium discharged from the waste heat recovery unit are monitored. Combined with a control valve body on the exhaust pipe for controlling the flow rate of the exhaust gas entering the waste heat recovery unit, and the third control valve for controlling the flow rate of the heat exchange medium entering the waste heat recovery unit, and the fourth control valve for controlling the flow rate of the heat exchange medium exiting the waste heat recovery unit, the flow rates of the exhaust gas and the heat exchange medium entering the waste heat recovery unit are adjusted according to the discharge temperature and pressure of the heat exchange medium in the waste heat recovery unit, thereby improving the heat exchange efficiency of the exhaust gas and making the temperature and pressure of the output heat exchange medium more stable.

Description

Technical Field

[0001] This application relates to the technical field of heat recovery equipment and transportation vehicles, and in particular to a waste heat recovery system, a control method for a waste heat recovery system, and a vehicle. Background Technology

[0002] Currently, heat recovery devices for automotive exhaust typically regulate the amount of heat exchanged by adjusting the flow rate of exhaust gas entering the heat exchanger. However, this method does not monitor the heat exchange effect of the exhaust gas, resulting in low heat exchange efficiency. Furthermore, existing heat recovery devices for automotive exhaust generally use coolant to exchange heat with the exhaust gas. The coolant flows on the outside of the casing, and the exhaust gas flows on the outside of the casing, resulting in simple liquid flow and low heat exchange efficiency.

[0003] It is evident that existing technologies still need improvement and enhancement. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this application is to provide a waste heat recovery system and its control method, as well as a vehicle, which aims to improve the heat exchange efficiency of automobile exhaust gas.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] This application discloses a waste heat recovery system, including:

[0007] A waste heat recovery unit is provided with a heat exchange medium flow channel and an exhaust gas flow channel, and the heat exchange medium flow channel and the exhaust gas flow channel can transfer heat to each other.

[0008] An exhaust pipe is used to connect to the exhaust end of the exhaust gas. The inlet end of the exhaust gas passage and the exhaust end of the exhaust gas passage are respectively connected to the exhaust pipe. A control valve body is provided on the exhaust pipe. The control valve body is used to control the flow rate of the exhaust gas entering the waste heat recovery unit in the exhaust pipe.

[0009] The third control valve is used to control the flow rate of the heat exchange medium entering the waste heat recovery unit;

[0010] The fourth control valve is used to control the flow rate of the heat exchange medium discharged from the waste heat recovery unit;

[0011] The first temperature and pressure sensor is used to detect the temperature and pressure of the heat exchange medium at the outlet end of the heat exchange medium flow channel in the waste heat recovery unit.

[0012] The controller is electrically connected to the control valve body, the third control valve, the fourth control valve, and the first temperature and pressure sensor, respectively.

[0013] In some embodiments of this application, the control valve body includes a first control valve and a second control valve;

[0014] The exhaust pipe includes:

[0015] The first exhaust pipe is equipped with the first control valve.

[0016] The second exhaust pipe is connected to the first exhaust pipe and communicates with the intake end of the tail flow channel. The second control valve is installed on the second exhaust pipe.

[0017] The third exhaust pipe is connected to the first exhaust pipe, located downstream of the second exhaust pipe, and communicates with the exhaust end of the tailpipe.

[0018] In some embodiments of this application, the system further includes:

[0019] An inlet buffer chamber is connected to the inlet end of the heat exchange medium flow channel. The inlet buffer chamber is provided with a heat exchange medium inlet. The third control valve is installed on the heat exchange medium inlet and is used to regulate the flow rate of the heat exchange medium entering the inlet buffer chamber.

[0020] An outlet buffer chamber is connected to the outlet end of the heat exchange medium flow channel. The outlet buffer chamber is provided with a heat exchange medium discharge port. The fourth control valve is installed on the heat exchange medium discharge port and is used to regulate the flow rate of the heat exchange medium discharged from the outlet buffer chamber.

[0021] In some embodiments of this application, a temperature sensor is provided on the first exhaust pipe, the temperature sensor is located upstream of the second control valve, a second temperature and pressure sensor is provided in the inlet buffer chamber, and the controller is electrically connected to the temperature sensor and the second temperature and pressure sensor respectively.

[0022] In some embodiments of this application, the waste heat recovery unit is provided with multiple layers of heat exchange working fluid flow channels along the axial and radial directions, and multiple layers of exhaust flow channels are provided along the axial and radial directions, with the heat exchange working fluid flow channels and the exhaust flow channels being arranged alternately; adjacent heat exchange working fluid flow channels are interconnected to form the heat exchange working fluid flow channels; adjacent exhaust flow channels are interconnected to form the exhaust flow channels.

[0023] In some embodiments of this application, the heat exchange medium flow channel is provided with a heat exchange medium inlet and a heat exchange medium outlet. The heat exchange medium inlet is located outside the heat exchange medium outlet, and the heat exchange medium inlet is located at one end of the waste heat recovery unit, while the heat exchange medium outlet is located at the other end of the waste heat recovery unit.

[0024] The air inlet of the exhaust channel is located inside the exhaust end of the exhaust channel. The air inlet of the exhaust channel and the heat exchange medium outlet are located at the same end of the waste heat recovery unit, and the air inlet of the exhaust channel is located inside the heat exchange medium outlet. The exhaust end of the exhaust channel and the heat exchange medium inlet are located at the same end of the waste heat recovery unit, and the exhaust end of the exhaust channel is located outside the heat exchange medium inlet.

[0025] This application also provides a control method for a waste heat recovery system, the control method being applicable to the waste heat recovery system as described in any of the preceding claims, the control method comprising the following steps:

[0026] Step S1. Set the target temperature range [Tfl_out_1, Tfl_out_2] and target pressure range [Pf1_out_1, Pf1_out_2] of the heat exchange medium at the outlet end of the heat exchange medium channel, where Tfl_out_1 <Tfl_out_2,Pf1_out_1<Pf1_out_2;

[0027] Step S2. Open the fourth control valve and the third control valve;

[0028] Step S3. Open the first control valve and the second control valve;

[0029] Step S4. Obtain the temperature Tf1_out and pressure Pf1_out of the heat exchange medium at the outlet end of the heat exchange medium flow channel;

[0030] Step S5. Determine the relationship between the temperature Tf1_out of the heat exchange medium at the outlet end of the heat exchange medium flow channel and the set target temperature range [Tfl_out_1, Tfl_out_2], and the pressure Pf1_out and the set target pressure range [Pf1_out_1, Pf1_out_2].

[0031] When the temperature Tf1_out of the heat exchange medium at the outlet end of the heat exchange medium channel is less than the lower limit Tf1_out_1 of the target temperature range, and the pressure Pf1_out is less than the lower limit Pf1_out_1 of the target pressure range, the opening angle of the second control valve is increased.

[0032] When the temperature Tf1_out of the heat exchange medium at the outlet end of the heat exchange medium channel is greater than the upper limit Tfl_out_2 of the target temperature range, and the pressure Pf1_out is greater than the upper limit Pf1_out_2 of the target pressure range, the opening angle of the second control valve is reduced.

[0033] In some embodiments of this application, step S1 further includes:

[0034] Set the normal temperature range of the exhaust gas before it enters the waste heat recovery unit [Texh_1, Texh_2], and the target pressure range of the heat exchange medium at the inlet of the heat exchange medium flow channel [Pf1_in_1, Pf1_in_2], where Texh_1 <Texh_2,Pf1_in_1<Pf1_in_2;

[0035] Step S4 also includes:

[0036] Obtain the temperature of the exhaust gas before it enters the waste heat recovery unit, Texh.

[0037] Obtain the temperature Tf1_in and pressure Pf1_in of the heat exchange medium at the inlet end of the heat exchange medium flow channel.

[0038] In some embodiments of this application, when the temperature Tf1_out of the heat exchange medium at the outlet end of the heat exchange medium flow channel is less than the lower limit Tf1_out_1 of the set target temperature range, step S5 further includes the following step:

[0039] Step A. Determine the difference between the temperature Tf1_in at the inlet of the heat exchange medium and the temperature Tf1_out at the outlet of the heat exchange medium. If Tf1_out is not less than Tf1_in, proceed to the next step; otherwise, delay for a certain period of time and re-execute step S4.

[0040] Step B. Determine the relationship between the pressure Pf1_in of the heat exchange medium at the inlet end of the heat exchange medium flow channel and the target pressure range [Pf1_in_1, Pf1_in_2].

[0041] If the pressure Pf1_in of the heat exchange medium at the inlet end of the heat exchange medium flow channel is less than the lower limit Pf1_in_1 of the set target pressure range, the pressure Pf1_out of the heat exchange medium at the outlet end of the heat exchange medium flow channel is less than the lower limit Pf1_out_1 of the set target pressure range, and the exhaust gas temperature Texh is greater than the lower limit Texh_1 of the set normal temperature range, the opening angle of the second control valve is increased and the system issues a fault alarm.

[0042] If the pressure of the heat exchange medium at the inlet end of the heat exchange medium channel, Pf1_in, is greater than the upper limit of its target pressure range, Pf1_in_2, and the pressure of the heat exchange medium at the outlet end of the heat exchange medium channel, Pf1_out, is less than the lower limit of its target pressure range, Pf1_out_1, the opening angle of the third control valve is reduced, and the system issues a fault alarm. If the exhaust gas temperature is within the set temperature range, the opening angle of the second control valve is reduced; if the exhaust gas temperature is greater than the upper limit of the set temperature range, Texh_2, the second control valve is closed.

[0043] This application also provides a vehicle that includes the waste heat recovery system as described in any of the preceding claims.

[0044] Beneficial effects:

[0045] The waste heat recovery system provided in this application monitors the temperature and pressure of the heat exchange medium discharged from the waste heat recovery unit by installing a first temperature and pressure sensor at the outlet end of the heat exchange medium flow channel of the waste heat recovery unit. Combined with a control valve on the exhaust pipe to control the flow rate of the exhaust gas entering the waste heat recovery unit, a third control valve to control the flow rate of the heat exchange medium entering the waste heat recovery unit, and a fourth control valve to control the flow rate of the heat exchange medium discharged from the waste heat recovery unit, the system adjusts the flow rates of the exhaust gas and the heat exchange medium entering the waste heat recovery unit according to the discharge temperature and pressure of the heat exchange medium in the waste heat recovery unit, thereby improving the heat exchange efficiency of the exhaust gas and making the temperature and pressure of the output heat exchange medium more stable.

[0046] The control method for the waste heat recovery system provided in this application, through the aforementioned waste heat recovery system, adjusts the flow rates of the exhaust gas and the heat exchange medium in real time, and possesses all the advantages of the aforementioned system.

[0047] The vehicle provided in this application, including the aforementioned waste heat recovery system, has high heat exchange efficiency for exhaust gas and can output a heat exchange medium with stable temperature and pressure. Attached Figure Description

[0048] Figure 1 This is a structural diagram of a waste heat recovery system provided in one embodiment of this application.

[0049] Figure 2 This is a schematic diagram showing the flow direction of exhaust gas in a waste heat recovery system provided in one embodiment of this application when the first control valve is closed and the second control valve is open.

[0050] Figure 3 This is a schematic diagram showing the flow direction of the heat exchange medium in a waste heat recovery system provided in one embodiment of this application.

[0051] Figure 4 This is a schematic diagram showing the flow direction of exhaust gas when the first control valve is open and the second control valve is closed in a waste heat recovery system provided in one embodiment of this application.

[0052] Figure 5 This is a schematic diagram of the structure of a waste heat recovery device provided in one embodiment of this application.

[0053] Figure 6 Flowchart of the control method for a waste heat recovery system provided in one embodiment of this application Figure 1 .

[0054] Figure 7Flowchart of the control method for a waste heat recovery system provided in one embodiment of this application Figure 2 .

[0055] Figure 8 Flowchart of the control method for a waste heat recovery system provided in one embodiment of this application Figure 3 .

[0056] Key component symbols: 1. Waste heat recovery unit; 11. Heat exchange medium flow channel; 111. Heat exchange medium inlet; 112. Heat exchange medium outlet; 113. Heat exchange medium flow channel layer; 12. Exhaust gas flow channel; 121. Air inlet end of exhaust gas flow channel; 122. Exhaust end of exhaust gas flow channel; 123. Exhaust gas flow channel layer; 2. Exhaust pipe; 21. First exhaust pipe; 22. Second exhaust pipe; 23. Third exhaust pipe; 3. Control valve body; 31. First control valve; 32. Second control valve; 4. Third control valve; 5. Fourth control valve; 6. First temperature and pressure sensor; 7. Inlet buffer chamber; 71. Heat exchange medium inlet; 8. Outlet buffer chamber; 81. Heat exchange medium outlet; 9. Temperature sensor; 10. Second temperature and pressure sensor. Detailed Implementation

[0057] This application provides a waste heat recovery system and its control method, as well as a vehicle. To make the objectives, technical solutions, and effects of this application clearer and more explicit, the following detailed description is provided with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining this application and are not intended to limit this application.

[0058] In the description of this application, it should be understood that the terms "upper," "lower," "left," and "right," etc., indicating orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or a specific orientational structure and operation. Therefore, they should not be construed as limitations on this application. Furthermore, "first" and "second" are only for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "multiple" means two or more.

[0059] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0060] Figure 1 This is a schematic diagram of the waste heat recovery system. Figure 2 This is a schematic diagram showing the flow direction of exhaust gas when the first control valve is closed and the second control valve is open in a waste heat recovery system. The arrows in the diagram indicate the flow direction of the exhaust gas. Figure 3 This is a schematic diagram of the flow direction of the heat exchange medium in a waste heat recovery system. The arrows in the diagram indicate the flow direction of the heat exchange medium. Figure 4 This diagram illustrates the flow direction of exhaust gas when the first control valve is open and the second control valve is closed in a waste heat recovery system. The arrows in the diagram indicate the flow direction of the exhaust gas.

[0061] As environmental protection requirements become increasingly stringent, the thermal efficiency requirements for gasoline-powered vehicles are also rising, and regulations on vehicle exhaust emissions are becoming more stringent. When vehicle exhaust exits the engine, it carries away a significant amount of heat (up to 30%). Recovering and utilizing this heat—for example, for power generation, engine warming, and battery heating—can reduce engine load, save energy, and indirectly improve engine thermal efficiency.

[0062] Please see Figure 1-4 This application provides a waste heat recovery system that recovers heat from exhaust gas by exchanging heat with a heat exchange medium; this waste heat recovery system is suitable for recovering heat from exhaust gas emitted by automobile engines.

[0063] The waste heat recovery system includes a waste heat recovery unit 1, an exhaust pipe 2, a third control valve 4, a fourth control valve 5, a first temperature and pressure sensor 6, and a controller (not shown in the figure).

[0064] The waste heat recovery unit 1 is equipped with a heat exchange medium flow channel 11 and an exhaust gas flow channel 12. The heat exchange medium flow channel 11 and the exhaust gas flow channel 12 can transfer heat to each other, transferring the heat in the exhaust gas to the heat exchange medium.

[0065] In order to improve the heat exchange efficiency between the heat exchange medium and the exhaust gas, the flow direction of the heat exchange medium in the heat exchange medium flow channel 11 is opposite to the flow direction of the exhaust gas in the exhaust gas flow channel 12.

[0066] The heat exchange medium uses phase change materials (PCMs). PCMs have good reversibility of phase change processes, can be recycled, and have low expansion and contraction, as well as high thermal conductivity. Specifically, PCMs can be selected from carbon dioxide, air conditioning refrigerants, water, etc.

[0067] The exhaust pipe 2 is used to connect to the exhaust end of the exhaust gas. The intake end and exhaust end of the exhaust gas passage 12 are respectively connected to the exhaust pipe 2, so that the exhaust gas after heat exchange can be discharged into the external environment along the exhaust pipe 2. A control valve body 3 is provided on the exhaust pipe 2. The control valve body 3 is used to control the flow rate of the exhaust gas entering the waste heat recovery unit 1 in the exhaust pipe 2. For example, when the waste heat recovery system is used to recover the heat of the exhaust gas of a car engine, the exhaust pipe 2 is connected to the exhaust gas outlet of the car engine, and the exhaust gas is introduced into the exhaust gas passage 12 of the waste heat recovery unit 1. The control valve body 3 on the exhaust pipe 2 can control the flow rate of the exhaust gas entering the waste heat recovery unit 1, thereby adjusting the heat exchange efficiency between the exhaust gas and the heat exchange medium.

[0068] The third control valve 4 is used to control the flow rate of the heat exchange medium entering the waste heat recovery unit 1, and the fourth control valve 5 is used to control the flow rate of the heat exchange medium exiting the waste heat recovery unit 1. The first temperature and pressure sensor 6 is used to detect the temperature and pressure of the heat exchange medium at the outlet end of the heat exchange medium in the waste heat recovery unit 1. Based on the temperature and pressure of the heat exchange medium detected by the first temperature and pressure sensor 6, the flow rates of the heat exchange medium and the exhaust gas are adjusted in conjunction with the third control valve 4, the fourth control valve 5, and the control valve body 3, so that the output temperature and pressure of the heat exchange medium can be maintained within a stable range, thereby improving the heat exchange efficiency.

[0069] The controller is electrically connected to control valve body 3, third control valve 4, fourth control valve 5, and first temperature and pressure sensor 6, respectively. The controller is a PLC controller, which improves the control accuracy of the system through unified control.

[0070] In some embodiments of this application, the control valve body 3 includes a first control valve 31 and a second control valve 32; the exhaust pipe 2 includes a first exhaust pipe 21, a second exhaust pipe 22, and a third exhaust pipe 23. The first exhaust pipe 21 is equipped with the first control valve 31. The second exhaust pipe 22 is connected to the first exhaust pipe 21 and communicates with the inlet end of the exhaust flow channel 12. The second control valve 32 is located on the second exhaust pipe 22. The third exhaust pipe 23 is connected to the first exhaust pipe 21, located downstream of the second exhaust pipe 22, and communicates with the exhaust end of the exhaust flow channel 12. The exhaust gas enters the exhaust flow channel 12 of the waste heat recovery unit 1 through the first exhaust pipe 21 and then enters the second exhaust pipe 22. After exchanging heat with the heat exchange medium in the waste heat recovery unit 1, it is discharged to the external environment through the third exhaust pipe 23. The exhaust gas that does not flow through the second exhaust pipe 22 can be directly discharged to the external environment through the first exhaust pipe 21. The first control valve 31 is used to control the flow rate of exhaust gas directly discharged into the external environment through the first exhaust pipe 21, and the second control valve 32 is used to control the flow rate of exhaust gas entering the waste heat recovery unit 1. Figure 2 As shown, when the first control valve 31 is closed and the second control valve 32 is open, the exhaust gas enters the second exhaust pipe 22 through the first exhaust pipe 21, and then enters the waste heat recovery unit 1. Figure 4 As shown, if the first control valve 31 is open and the second control valve 32 is closed, the high-level exhaust gas will be directly discharged into the external environment through the first exhaust pipe 21.

[0071] The opening angles of the first control valve 31 and the second control valve 32 can be adjusted. For example, when the temperature at the outlet of the heat exchange medium flow channel 11 is too low, the opening angle of the second control valve 32 can be increased to increase the amount of exhaust gas entering the waste heat recovery unit 1, allowing for sufficient heat exchange with the heat exchange medium. Conversely, when the temperature at the outlet of the heat exchange medium flow channel 11 is too high, the opening angle of the second control valve 32 can be reduced or directly closed, while the opening angle of the first control valve 31 is increased to reduce the flow rate of exhaust gas entering the waste heat recovery unit 1, enabling the waste heat recovery unit 1 to output a heat exchange medium with stable temperature and pressure.

[0072] Furthermore, the waste heat recovery system also includes an inlet buffer chamber 7 and an outlet buffer chamber 8. The inlet buffer chamber 7 is connected to the inlet end of the heat exchange medium flow channel 11, and has a heat exchange medium inlet 71. A third control valve 4 is installed on the heat exchange medium inlet 71 to regulate the flow rate of the heat exchange medium entering the inlet buffer chamber 7. The outlet buffer chamber 8 is connected to the outlet end of the heat exchange medium flow channel 11, and has a heat exchange medium outlet 81. A fourth control valve 5 is installed on the heat exchange medium outlet 81 to regulate the flow rate of the heat exchange medium exiting the outlet buffer chamber 8. The inlet buffer chamber 7 is provided at the inlet end of the heat exchange medium flow channel 11 to buffer the heat exchange medium before it enters the waste heat recovery unit 1. By adjusting the third control valve 4, the pressure in the inlet buffer chamber 7 is maintained at a stable state, ensuring that the heat exchange medium enters the waste heat recovery unit 1 under a stable pressure, thus preventing excessive pressure or flow rate of the heat exchange medium entering the waste heat recovery unit 1 and avoiding damage to the internal structure of the waste heat recovery unit 1. An outlet buffer chamber 8 is provided at the outlet end of the heat exchange medium flow channel 11 to buffer the heat exchange medium discharged from the waste heat recovery unit 1. By adjusting the fourth control valve 5, the pressure of the heat exchange medium discharged from the outlet buffer chamber 8 is maintained at a stable state. Furthermore, the heat exchange medium after heat exchange is generally used to provide heat for other components of the vehicle. Maintaining a stable pressure of the heat exchange medium discharged from the outlet buffer chamber can improve the stability of the operation of subsequent components.

[0073] Furthermore, a temperature sensor 9 is installed on the first exhaust pipe 21, located upstream of the second control valve 32. A second temperature and pressure sensor 10 is installed in the inlet buffer chamber 7. The controller is electrically connected to both the temperature sensor 9 and the second temperature and pressure sensor 10. The temperature sensor 9 is used to monitor whether the exhaust gas in the first exhaust pipe 21 is within the normal temperature range. Preferably, the temperature sensor 9 should be as close as possible to the intake end of the first exhaust pipe 21 to more accurately reflect the temperature of the exhaust gas when it is discharged from the car engine, thereby more accurately monitoring the temperature of the exhaust gas. Furthermore, by monitoring the temperature of the exhaust gas, combined with the temperature and pressure in the inlet buffer chamber 7 and the outlet buffer chamber 8, the controller can accurately calculate the increase or decrease of the opening angle of the second control valve 32, thereby controlling the increase or decrease of the opening angle of the second control valve 32 and improving the heat exchange accuracy of the waste heat recovery system.

[0074] Figure 5 This is a schematic diagram of a waste heat recovery unit.

[0075] like Figure 1 and 5As shown, furthermore, multiple layers of heat exchange working fluid flow channels 113 are respectively arranged along the axial and radial directions inside the waste heat recovery unit 1, and multiple layers of tail gas flow channels 123 are respectively arranged along the axial and radial directions inside the waste heat recovery unit 1. The heat exchange working fluid flow channels 113 and the tail gas flow channels 123 are arranged alternately. Adjacent heat exchange working fluid flow channels 113 are interconnected to form heat exchange working fluid flow channels 11. Adjacent tail gas flow channels 123 are interconnected to form tail gas flow channels 12. The heat exchange working fluid flow channels 113 and the tail gas flow channels 123 are arranged in multiple layers and are arranged alternately, so that the heat exchange working fluid and the tail gas can fully exchange heat, improve the utilization efficiency of the heat exchange working fluid, and fully recover the heat of the tail gas.

[0076] One or more small holes are formed on the exhaust gas flow channel layer 123 along the direction of exhaust gas flow, allowing the exhaust gas flow channel layers 123 to communicate with each other. The design of the small holes can prolong the residence time of the exhaust gas in the corresponding exhaust gas flow channel layer 123, thereby improving the heat exchange efficiency between the exhaust gas and the heat exchange medium. One or more small holes are formed on the heat exchange medium flow channel layer 113 along the direction of heat exchange medium flow, allowing the heat exchange medium flow channel layers 113 to communicate with each other. The design of the small holes can prolong the residence time of the heat exchange medium in the heat exchange medium flow channel layer 113, thereby further improving the heat exchange efficiency between the exhaust gas and the heat exchange medium.

[0077] Furthermore, the heat exchange medium flow channel 11 is provided with a heat exchange medium inlet 111 and a heat exchange medium outlet 112. The heat exchange medium inlet 111 is located outside the heat exchange medium outlet 112, and the heat exchange medium inlet 111 is located at one end of the waste heat recovery unit 1, while the heat exchange medium outlet 112 is located at the other end of the waste heat recovery unit 1. The air inlet end of the exhaust flow channel 12 is located inside the exhaust end of the exhaust flow channel 12. The air inlet end of the exhaust flow channel 12 and the heat exchange medium outlet 112 are located at the same end of the waste heat recovery unit 1, and the air inlet end of the exhaust flow channel 12 is located inside the heat exchange medium outlet 112. The exhaust end of the exhaust flow channel 12 and the heat exchange medium inlet 111 are located at the same end of the waste heat recovery unit 1, and the exhaust end of the exhaust flow channel 12 is located outside the heat exchange medium inlet 111. In the waste heat recovery unit 1, the innermost layer along its radial direction is the exhaust gas channel layer 123, and the outermost layer is also a high-temperature gas layer. The inlet end of the exhaust gas channel 12 is located in the middle of the radial direction of the waste heat recovery unit 1, and the exhaust end of the exhaust gas channel 12 is located on the outermost side of the radial direction of the waste heat recovery unit 1. In this way, the exhaust gas flows from the innermost side to the outer side of the waste heat recovery unit 1, and the heat exchange medium flows from the outer side to the inner side of the waste heat recovery unit 1, so that the heat exchange medium exchanges heat with the gradually increasing temperature of the exhaust gas from the outside to the inside, gradually raising the temperature and facilitating the control of the phase change of the heat exchange medium.

[0078] Figure 6 This is a flowchart of the control method for a waste heat recovery system.

[0079] like Figure 6As shown in the figure, on the other hand, the present application also provides a control method for a waste heat recovery system. This control method is applicable to any of the waste heat recovery systems described above, and the control method includes the following steps:

[0080] Step S1. Set the target temperature range [Tfl_out_1, Tfl_out_2] and the target pressure range [Pf1_out_1, Pf1_out_2] of the heat transfer working medium at the outlet end of the heat transfer working medium flow channel 11, where Tfl_out_1 < Tfl_out_2 and Pf1_out_1 < Pf1_out_2; when the waste heat recovery system is provided with an outlet buffer chamber 8 at the outlet end of the heat transfer working medium flow channel 11, the temperature and pressure at the outlet end of the heat transfer working medium flow channel 11 can be the temperature and pressure of the heat transfer working medium in the outlet buffer chamber 8 respectively. Among them, the target temperature range of the heat transfer working medium at the outlet end of the heat transfer working medium flow channel 11 can be set according to the requirements of the demand side or the component system, so that the output heat transfer working medium is suitable for the utilization of downstream components; the pressure range of the heat transfer working medium at the outlet end of the heat transfer working medium flow channel 11 can be used to judge the pressure deviation of the heat transfer working medium. For example, Pf1_out_1 = 5 kPa and Pf1_out_2 = 10 kPa can be set. When the pressure of the heat transfer working medium at the outlet end of the heat transfer working medium flow channel 11 is between 5 kPa and 10 kPa, the pressure is in a normal state; if the pressure deviates, the cause of the failure can be judged by combining other data.

[0081] Step S2. Open the fourth control valve 5 and the third control valve 4 to allow the heat transfer working medium to flow through the waste heat recovery device 1; generally, first open the fourth control valve 5 and then open the third control valve 4 to form a passage at the outlet end of the heat transfer working medium flow channel 11 of the waste heat recovery device 1 first, avoiding an instantaneous increase in the pressure inside the waste heat recovery device 1 and damaging the internal structure of the waste heat recovery device 1.

[0082] Step S3. Open the first control valve 31 and the second control valve 32 to allow the tail gas to enter the waste heat recovery device 1. When the demand for heat energy by other components connected to the waste heat recovery system is large, the first control valve 31 can also be closed and only the second control valve 32 is opened, so that the tail gas all flows to the waste heat recovery device through the second exhaust pipe 22.

[0083] Step S4. Obtain the temperature Tf1_out and pressure Pf1_out of the heat transfer working medium at the outlet end of the heat transfer working medium flow channel 11; the temperature and pressure can be obtained by the first temperature and pressure sensor 6 at the outlet end of the heat transfer working medium flow channel 11, and after the first temperature and pressure sensor 6 obtains the temperature and pressure data, it transmits them to the controller.

[0084] Step S5. The controller compares the temperature Tf1_out of the heat exchange medium at the outlet end of the heat exchange medium flow channel 11 with the target temperature range [Tfl_out_1, Tfl_out_2] and the pressure Pf1_out with the target pressure range [Pf1_out_1, Pf1_out_2] based on the received data.

[0085] When the temperature Tf1_out of the heat exchange medium at the outlet of heat exchange medium channel 11 is less than the lower limit Tf1_out_1 of the target temperature range, and the pressure Pf1_out is less than the lower limit Pf1_out_1 of the target pressure range, the opening angle of the second control valve 32 is increased to allow more exhaust gas to enter the waste heat recovery unit 1 for sufficient heat exchange with the heat exchange medium, thereby improving heat exchange efficiency. At this time, the third control valve 4 can also be adjusted accordingly to reduce the flow rate of the heat exchange medium entering the waste heat recovery unit 1, thereby improving the utilization rate of the heat exchange medium. It is worth noting that at this time, the temperature of the heat exchange medium at the inlet of heat exchange medium channel 11 is less than the temperature of the heat exchange medium at the outlet of heat exchange medium channel 11. After the opening angle of the second control valve 32 is increased, the system re-acquires the temperature and pressure of the heat exchange medium at the outlet of heat exchange medium channel 11 after a certain delay, such as 10 to 30 seconds.

[0086] If the temperature of the heat exchange medium at the outlet end of the heat exchange medium flow channel 11 is within the target temperature range, the system delays for a certain period of time, such as 10 to 30 seconds, and then re-acquires the temperature and pressure of the heat exchange medium at the outlet end of the heat exchange medium flow channel 11.

[0087] When the temperature Tf1_out of the heat exchange medium at the outlet of the heat exchange medium channel 11 is greater than the upper limit Tfl_out_2 of the target temperature range, and the pressure Pf1_out is greater than the upper limit Pf1_out_2 of the target pressure range, the opening angle of the second control valve 32 is reduced, and the opening angle of the first control valve 31 is increased. This reduces the flow rate of the exhaust gas entering the waste heat recovery unit 1 and increases the flow rate of the exhaust gas directly discharged to the external environment, causing more heat exchange medium to undergo phase change and reducing the pressure of the heat exchange medium at the outlet of the heat exchange medium channel 11. After adjusting the opening angles of the second control valve 32 and the first control valve 31, the system re-acquires the temperature and pressure of the heat exchange medium at the outlet of the heat exchange medium channel 11 after a certain delay, such as 10 to 30 seconds.

[0088] If the temperature Tf1_out of the heat exchange working medium at the outlet end of the heat exchange working medium flow channel 11 is greater than the upper limit Tfl_out_2 of the target temperature range, but its pressure Pf1_out is less than the upper limit Pf1_out_2 of the target pressure range, the opening angle of the third control valve 4 can be increased to increase the flow rate at the inlet end of the heat exchange working medium flow channel 11, allowing more heat exchange working medium to enter the waste heat recovery device 1 and reducing the temperature of the heat exchange working medium at the outlet end of the heat exchange working medium flow channel 11. After adjusting the opening angle of the third control valve 4, the system delays for a certain period of time, such as 10 - 30 s, and then re-acquires the temperature and pressure of the heat exchange working medium at the outlet end of the heat exchange working medium flow channel 11.

[0089] Figure 7 It is a flowchart of the control method for the waste heat recovery system.

[0090] Such as Figure 7 As shown, in some embodiments of the present application, in addition to the above steps, before opening the third control valve 4 and the fourth control valve 5, the following steps are further included:

[0091] Set the normal temperature range [Texh_1, Texh_2] of the tail gas before entering the waste heat recovery device 1, where Texh_1 < Texh_2; judge whether the exhaust temperature of the engine is normal based on this temperature range. For example, Texh_1 can be set to 20 °C and Texh_2 can be set to 500 °C.

[0092] Set the target pressure range [Pf1_in_1, Pf1_in_2] of the heat exchange working medium at the inlet end of the heat exchange working medium flow channel 11, where Pf1_in_1 < Pf1_in_2; by comparing the pressure of the heat exchange working medium at the inlet end of the heat exchange working medium flow channel 11 measured in real time with the size relationship of this pressure range, it can be judged whether there is a fault in the flow of the heat exchange working medium. When the inlet end of the heat exchange working medium flow channel 11 of the waste heat recovery device 1 is connected with an inlet buffer chamber, the temperature and pressure of the heat exchange working medium at the inlet end of the heat exchange working medium flow channel 11 can be the temperature and pressure of the heat exchange working medium in the inlet buffer chamber 7.

[0093] After opening the first control valve 31 and the second control valve 32, the following steps are further included:

[0094] Obtain the temperature Texh of the tail gas before entering the waste heat recovery device 1;

[0095] Obtain the temperature Tf1_in and pressure Pf1_in of the heat transfer working medium at the inlet end of the heat transfer working medium flow channel 11. Based on the above-obtained data, when it is necessary to increase the opening angle of the second control valve 32, the increased opening angle can be calculated. It can be understood that when it is necessary to increase the opening angle of the second control valve 32, the temperature Tf1_in of the heat transfer working medium at the inlet end of the heat transfer working medium flow channel 11 is not greater than the temperature Tf1_out at its outlet end, and the temperature Texh of the tail gas is greater than the lower limit Texh_1 of the set normal temperature range;

[0096] The specific calculation method for the increased opening angle of the second control valve 32 is shown in Equation (1):

[0097]

[0098] Among them, a1 is the flow coefficient, and 0 < a1 < 0.9;

[0099] a1 is obtained by preliminary calibration. The higher the engine speed, the smaller a1, and vice versa.

[0100] When the temperature Tf1_out of the heat transfer working medium at the outlet end of the heat transfer working medium flow channel 11 is not less than the temperature Tf1_in at its inlet end, and is greater than the upper limit Tf1_out_2 of its target temperature range, the pressure of the heat transfer working medium at the outlet end of the heat transfer working medium flow channel 11 is greater than the upper limit Pf1_out_2 of the target pressure range, and the temperature of the tail gas is greater than the upper limit Texh_2 of its normal temperature range, the specific calculation of the decreased opening angle of the second control valve 32 is shown in Equation (2):

[0101]

[0102] Among them, a1 is the flow coefficient, and 0 < a1 < 0.9.

[0103] When the temperature Tf1_out of the heat transfer working medium at the outlet end of the heat transfer working medium flow channel 11 is not less than the temperature Tf1_in at its inlet end, and is greater than the upper limit Tf1_out_2 of its target temperature range, the pressure of the heat transfer working medium at the outlet end of the heat transfer working medium flow channel 11 is greater than the upper limit Pf1_out_2 of the target pressure range, and the temperature of the tail gas is not greater than the upper limit Texh_2 of its normal temperature range, the specific calculation of the decreased opening angle of the second control valve 32 is shown in Equation (3):

[0104]

[0105] Among them, a1 is the flow coefficient, 0 < a1 < 0.9; b1 is the exhaust temperature weighting coefficient,

[0106]

[0107] Generally, after adjusting the opening angle of the first control valve 31, the opening angle of the third control valve 4 needs to be adjusted accordingly. Specifically, the opening increase angle Aef1_inc of the third control valve 4 is calculated using equation (5):

[0108]

[0109] Where c1 is the temperature weighting coefficient;

[0110]

[0111] The reduced opening angle Aefl_dec of the third control valve 4 is calculated using equation (7):

[0112]

[0113] Where d1 is the temperature weighting coefficient;

[0114]

[0115] Figure 8 This is a flowchart of the control method for a waste heat recovery system.

[0116] Please see Figure 8 In some embodiments of this application, the method further includes determining the magnitude of the temperature Tf1_in of the heat exchange medium at the outlet end of the heat exchange medium flow channel 11 and the temperature Tf1_out of the heat exchange medium at the outlet end of the heat exchange medium flow channel 11 when the temperature Tf1_out at the outlet end of the heat exchange medium flow channel 11 is less than the lower limit Tf1_out_1 of the set target temperature range.

[0117] a. If Tf1_out is less than Tf1_in, the system re-acquires the exhaust gas temperature Texh, the heat exchange medium temperature Tf1_in and pressure Pf1_in at the inlet end of the heat exchange medium flow channel 11, and the heat exchange medium temperature Tf1_out and pressure Pf1_out at the outlet end of the heat exchange medium flow channel 11 after a certain delay.

[0118] b. If Tf1_out is not less than Tf1_in, determine the relationship between the pressure Pf1_in of the heat exchange medium at the inlet end of the heat exchange medium flow channel 11 and the target pressure range [Pf1_in_1, Pf1_in_2].

[0119] b1. If the pressure Pf1_in of the heat exchange medium at the inlet end of the heat exchange medium flow channel 11 is less than the lower limit Pf1_in_1 of the set pressure range; determine the relationship between the pressure Pf1_out of the heat exchange medium at the outlet end of the heat exchange medium flow channel 11 and the set target pressure range [Pf1_out_1, Pf1_out_2].

[0120] b1-1. If the pressure Pf1_out of the heat exchange medium at the outlet end of the heat exchange medium flow channel 11 is less than the lower limit Pf1_out_1 of the set pressure range, and the temperature Texh of the exhaust gas is greater than the lower limit Texh_1 of the set lower temperature range, the opening angle of the second control valve 32 is increased. If the temperature Texh of the exhaust gas is still greater than the lower limit Texh_1 of the set lower temperature range after repeatedly acquiring the temperature of the exhaust gas (e.g., repeating 100 times), the system issues a fault alarm for low exhaust temperature. After a certain delay, the system reacquires the temperature Texh of the exhaust gas, the temperature Tf1_in and pressure Pf1_in of the heat exchange medium at the inlet end of the heat exchange medium flow channel 11, and the temperature Tf1_out and pressure Pf1_out of the heat exchange medium at the outlet end of the heat exchange medium flow channel 11.

[0121] b1-2. If the pressure Pf1_out of the heat exchange medium at the outlet end of the heat exchange medium flow channel 11 is within the target pressure range [Pf1_in_1, Pf1_in_2], the system delays for a certain period of time to reacquire the temperature Texh of the exhaust gas, the temperature Tf1_in and pressure Pf1_in of the heat exchange medium at the inlet end of the heat exchange medium flow channel 11, and the temperature Tf1_out and pressure Pf1_out of the heat exchange medium at the outlet end of the heat exchange medium flow channel 11.

[0122] b1-3. If the pressure Pf1_out of the heat exchange medium at the outlet end of the heat exchange medium flow channel 11 is greater than the upper limit Pf1_out_2 of the set target pressure range, reduce the opening angle of the third control valve 4.

[0123] b2. If the pressure Pf1_in of the heat exchange medium at the inlet end of the heat exchange medium flow channel 11 is within the set target pressure range [Pf1_in_1, Pf1_in_2], the system re-acquires the temperature Texh of the exhaust gas, the temperature Tf1_in and pressure Pf1_in of the heat exchange medium at the inlet end of the heat exchange medium flow channel 11, and the temperature Tf1_out and pressure Pf1_out of the heat exchange medium at the outlet end of the heat exchange medium flow channel 11 after a certain delay.

[0124] b3. If the pressure Pf1_in of the heat exchange medium at the inlet end of the heat exchange medium flow channel 11 is greater than the upper limit Pf1_in_2 of its target pressure range, determine the relationship between the pressure Pf1_out of the heat exchange medium at the outlet end of the heat exchange medium flow channel 11 and the lower limit Pf1_out_1 of its target pressure range.

[0125] b3-1. If the pressure of the heat exchange medium at the outlet end of the heat exchange medium flow channel 11 is not less than the lower limit of its target pressure range Pf1_out_1, the system re-acquires the temperature Texh of the exhaust gas, the temperature Tf1_in and pressure Pf1_in of the heat exchange medium at the inlet end of the heat exchange medium flow channel 11, and the temperature Tf1_out and pressure Pf1_out of the heat exchange medium at the outlet end of the heat exchange medium flow channel 11 after a certain delay.

[0126] b3-2. If the pressure Pf1_out of the heat exchange medium at the outlet of the heat exchange medium channel 11 is less than the lower limit Pf1_out_1 of its target pressure range, and Pf1_out is still less than Pf1_out_1 after repeated measurements, reduce the opening angle of the third control valve 4.

[0127] If the measurement is repeated multiple times, determine whether the pressure Pf1_out of the heat exchange medium at the outlet of the heat exchange medium channel 11 is still less than the lower limit Pf1_out_1 of its target pressure range;

[0128] If not, the system will reacquire the exhaust gas temperature Texh, the heat exchange medium temperature Tf1_in and pressure Pf1_in at the inlet end of the heat exchange medium flow channel 11, and the heat exchange medium temperature Tf1_out and pressure Pf1_out at the outlet end of the heat exchange medium flow channel 11 after a certain delay.

[0129] If so, the system issues a fault alarm indicating that the pressure at the inlet end (inlet buffer chamber 7) of the heat exchange medium flow channel 11 is too high. If the exhaust gas temperature is within the set temperature range, the opening angle of the second control valve 32 is reduced, and the system re-acquires the exhaust gas temperature Texh, the heat exchange medium temperature Tf1_in and pressure Pf1_in at the inlet end of the heat exchange medium flow channel 11, and the heat exchange medium temperature Tf1_out and pressure Pf1_out at the outlet end of the heat exchange medium flow channel 11 after a certain delay. If the exhaust gas temperature is greater than the upper limit Texh_2 of the set temperature range, the second control valve 32 is closed. The system re-acquires the exhaust gas temperature Texh, the heat exchange medium temperature Tf1_in and pressure Pf1_in at the inlet end of the heat exchange medium flow channel 11, and the heat exchange medium temperature Tf1_out and pressure Pf1_out at the outlet end of the heat exchange medium flow channel 11 after a certain delay.

[0130] In the above embodiments, the system delay time can be set according to actual usage needs, and is not limited here.

[0131] This application also provides a vehicle, specifically a gasoline-powered automobile, which includes a waste heat recovery system as described in any of the preceding claims. The intake end of the first exhaust pipe 2 in the waste heat recovery system is connected to the exhaust outlet of the vehicle's engine, enabling the exhaust gas from the engine to be introduced into the waste heat recovery unit 1 for heat exchange with a phase change material serving as the heat exchange medium, outputting a heat exchange medium with stable pressure and temperature.

[0132] The heat carried by the heat exchange medium discharged from the waste heat recovery unit 1 can be recovered and utilized for the vehicle's power generation, engine warming, and battery heating. After releasing heat, the heat exchange medium re-enters the waste heat recovery unit 1 through the inlet buffer chamber 7 via the circulation loop to exchange heat with the exhaust gas. By recovering and utilizing the heat of the exhaust gas, the thermal efficiency of the vehicle engine is indirectly improved.

[0133] The structure of the waste heat recovery system is as described in any of the above embodiments, and will not be repeated here.

[0134] In summary, the waste heat recovery system disclosed in this application collects the temperature and pressure of the heat exchange medium at the outlet end of the heat exchange medium through the first temperature and pressure sensor 6. It works in conjunction with the first control valve 31 and the second control valve 32 to regulate the flow rate of the exhaust gas entering the waste heat recovery unit 1, the third control valve 4 to regulate the flow rate of the heat exchange medium entering the waste heat recovery unit 1, and the fourth control valve 5 to regulate the flow rate of the heat exchange medium discharged from the waste heat recovery unit 1. This enables the waste heat recovery system to output a stable temperature and pressure for the heat exchange medium, improve heat exchange efficiency, and prevent damage caused by excessive internal pressure.

[0135] In addition, the use of phase change material as heat exchange medium provides a stable heat exchange medium, which further improves the heat exchange effect. The exhaust gas channel 12 and the heat exchange medium channel 11 inside the waste heat recovery unit 1 are arranged in a multi-layered manner, and the high temperature gas flows from the inside to the outside and the heat exchange medium flows from the outside to the inside, which further improves the heat exchange efficiency.

[0136] It is understood that those skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of this application, and all such substitutions or changes should fall within the protection scope of the appended claims.

Claims

1. A waste heat recovery system, characterized in that, include: A waste heat recovery unit includes heat exchange medium channels and exhaust gas channels. The heat exchange medium channels and exhaust gas channels are capable of mutual heat transfer. Multiple layers of heat exchange medium channels and multiple layers of exhaust gas channels are arranged axially and radially within the waste heat recovery unit, with the heat exchange medium channels and exhaust gas channels being staggered. One or more small holes are formed in each heat exchange medium channel layer along the direction of the heat exchange medium's movement, allowing adjacent heat exchange medium channels to communicate and form the heat exchange medium channel. Similarly, one or more small holes are formed in each exhaust gas channel layer along the direction of the exhaust gas's movement, allowing adjacent exhaust gas channel layers to communicate and form the exhaust gas channel. The exhaust channel has a heat exchange medium inlet and an outlet. The heat exchange medium inlet is located outside the heat exchange medium outlet and is situated at one end of the waste heat recovery unit. The heat exchange medium outlet is situated at the other end of the waste heat recovery unit. The air inlet of the exhaust channel is located inside the exhaust end of the exhaust channel. The air inlet of the exhaust channel and the heat exchange medium outlet are located at the same end of the waste heat recovery unit, and the air inlet of the exhaust channel is located inside the heat exchange medium outlet. The exhaust end of the exhaust channel and the heat exchange medium inlet are located at the same end of the waste heat recovery unit, and the exhaust end of the exhaust channel is located outside the heat exchange medium inlet. An exhaust pipe is used to connect to the exhaust end of the exhaust gas. The inlet end of the exhaust gas passage and the exhaust end of the exhaust gas passage are respectively connected to the exhaust pipe. A control valve body is provided on the exhaust pipe. The control valve body is used to control the flow rate of the exhaust gas entering the waste heat recovery unit in the exhaust pipe. The third control valve is used to control the flow rate of the heat exchange medium entering the waste heat recovery unit; The fourth control valve is used to control the flow rate of the heat exchange medium discharged from the waste heat recovery unit; The first temperature and pressure sensor is used to detect the temperature and pressure of the heat exchange medium at the outlet end of the heat exchange medium flow channel in the waste heat recovery unit. The controller is electrically connected to the control valve body, the third control valve, the fourth control valve, and the first temperature and pressure sensor, respectively.

2. The waste heat recovery system according to claim 1, characterized in that, The control valve body includes a first control valve and a second control valve; The exhaust pipe includes: The first exhaust pipe is equipped with the first control valve. The second exhaust pipe is connected to the first exhaust pipe and communicates with the intake end of the tail flow channel. The second control valve is installed on the second exhaust pipe. The third exhaust pipe is connected to the first exhaust pipe, located downstream of the second exhaust pipe, and communicates with the exhaust end of the tailpipe.

3. The waste heat recovery system according to claim 2, characterized in that, The system also includes: An inlet buffer chamber is connected to the inlet end of the heat exchange medium flow channel. The inlet buffer chamber is provided with a heat exchange medium inlet. The third control valve is installed on the heat exchange medium inlet and is used to regulate the flow rate of the heat exchange medium entering the inlet buffer chamber. An outlet buffer chamber is connected to the outlet end of the heat exchange medium flow channel. The outlet buffer chamber is provided with a heat exchange medium discharge port. The fourth control valve is installed on the heat exchange medium discharge port and is used to regulate the flow rate of the heat exchange medium discharged from the outlet buffer chamber.

4. The waste heat recovery system according to claim 3, characterized in that, A temperature sensor is provided on the first exhaust pipe, and the temperature sensor is located upstream of the second control valve. A second temperature and pressure sensor is provided in the inlet buffer chamber. The controller is electrically connected to the temperature sensor and the second temperature and pressure sensor respectively.

5. A control method for a waste heat recovery system, characterized in that, The control method is applicable to the waste heat recovery system as described in any one of claims 2 to 4, and the control method includes the following steps: Step S1. Set the target temperature range [Tfl_out_1, Tfl_out_2] and target pressure range [Pf1_out_1, Pf1_out_2] of the heat exchange medium at the outlet end of the heat exchange medium channel, where Tfl_out_1 <Tfl_out_2,Pf1_out_1<Pf1_out_2; Step S2. Open the fourth control valve and the third control valve; Step S3. Open the first control valve and the second control valve; Step S4. Obtain the temperature Tf1_out and pressure Pf1_out of the heat exchange medium at the outlet end of the heat exchange medium flow channel; Step S5. Determine the relationship between the temperature Tf1_out of the heat exchange medium at the outlet end of the heat exchange medium flow channel and the set target temperature range [Tfl_out_1, Tfl_out_2], and the pressure Pf1_out and the set target pressure range [Pf1_out_1, Pf1_out_2]. When the temperature Tf1_out of the heat exchange medium at the outlet end of the heat exchange medium channel is less than the lower limit Tf1_out_1 of the target temperature range, and the pressure Pf1_out is less than the lower limit Pf1_out_1 of the target pressure range, the opening angle of the second control valve is increased. When the temperature Tf1_out of the heat exchange medium at the outlet end of the heat exchange medium channel is greater than the upper limit Tfl_out_2 of the target temperature range, and the pressure Pf1_out is greater than the upper limit Pf1_out_2 of the target pressure range, the opening angle of the second control valve is reduced.

6. The control method for the waste heat recovery system according to claim 5, characterized in that, Step S1 also includes: Set the normal temperature range [Texh_1, Texh_2] of the exhaust gas before entering the waste heat recovery unit, and the target pressure range [Pf1_in_1, Pf1_in_2] of the heat exchange medium at the inlet of the heat exchange medium flow channel, where Texh_1 <Texh_2,Pf1_in_1<Pf1_in_2; Step S4 also includes: Obtain the temperature of the exhaust gas before it enters the waste heat recovery unit, Texh. Obtain the temperature Tf1_in and pressure Pf1_in of the heat exchange medium at the inlet end of the heat exchange medium flow channel.

7. The control method for the waste heat recovery system according to claim 6, characterized in that, In step S5, when the temperature Tf1_out of the heat exchange medium at the outlet of the heat exchange medium channel is less than the lower limit Tf1_out_1 of the set target temperature range, the following steps are also included: Step A. Determine the difference between the temperature Tf1_in at the inlet of the heat exchange medium and the temperature Tf1_out at the outlet of the heat exchange medium. If Tf1_out is not less than Tf1_in, proceed to the next step; otherwise, delay for a certain period of time and re-execute step S4. Step B. Determine the relationship between the pressure Pf1_in of the heat exchange medium at the inlet end of the heat exchange medium flow channel and the target pressure range [Pf1_in_1, Pf1_in_2]. If the pressure Pf1_in of the heat exchange medium at the inlet end of the heat exchange medium flow channel is less than the lower limit Pf1_in_1 of the set target pressure range, the pressure Pf1_out of the heat exchange medium at the outlet end of the heat exchange medium flow channel is less than the lower limit Pf1_out_1 of the set target pressure range, and the exhaust gas temperature Texh is greater than the lower limit Texh_1 of the set normal temperature range, the opening angle of the second control valve is increased and the system issues a fault alarm. If the pressure of the heat exchange medium at the inlet end of the heat exchange medium channel, Pf1_in, is greater than the upper limit of its target pressure range, Pf1_in_2, and the pressure of the heat exchange medium at the outlet end of the heat exchange medium channel, Pf1_out, is less than the lower limit of its target pressure range, Pf1_out_1, the opening angle of the third control valve is reduced, and the system issues a fault alarm. If the exhaust gas temperature is within the set temperature range, the opening angle of the second control valve is reduced; if the exhaust gas temperature is greater than the upper limit of the set temperature range, Texh_2, the second control valve is closed.

8. A vehicle, characterized in that, Includes the waste heat recovery system as described in any one of claims 1 to 4.

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