Device and method for adjusting active temperature of SCR (Selective Catalytic Reduction) catalyst by utilizing thermoelectric power generation system

Abstract

The invention belongs to the field of exhaust emission, and discloses a device and method for adjusting the active temperature of an SCR catalyst through a thermoelectric power generation system.The device comprises an engine cooling system, the engine cooling system is connected with a cold end radiator of the thermoelectric power generation system, and a thermoelectric power generation plate is connected with a storage battery through a power supply module; the second temperature sensor is arranged at an outlet of the electric heating device, the first temperature sensor and the second temperature sensor are connected with the engine control unit, the engine control unit is connected with the power supply module, the electric heating device is connected with the storage battery through the power supply module, and the engine control unit is used for controlling charging and discharging of the storage battery. When the SCR device is in the efficient temperature interval, the engine control unit controls the power supply module to charge the storage battery through the thermoelectric power generation system; and when the SCR device is out of the efficient temperature interval, the storage battery is used for discharging the electric heating device or controlling the engine cooling system to use a cold end radiator of the thermoelectric power generation system to forcibly dissipate heat so as to adjust the temperature of the SCR device.

Description

Technical Field

[0001] The present invention belongs to the technical field of exhaust gas emission, and relates to a device and method for regulating the active temperature of an SCR catalyst by using a thermoelectric power generation system. Background Art

[0002] As of 2022, the national emissions of nitrogen oxides (NO x ) from motor vehicles were 5.267 million tons. Among them, the NO x emissions from diesel vehicles exceeded 80% of the total vehicle emissions. Therefore, emission regulations have clearly defined limits for NO x emissions from diesel engines. To reduce NO x emissions from diesel engines, the most effective method currently is to use selective catalytic reduction technology (SCR). Under the action of a catalyst, a reducing agent such as ammonia or urea is injected to reduce NO in the tail gas x to N2 and H2O. The efficient operating temperature range of the SCR catalyst is usually between 200°C and 400°C. However, when the diesel engine is in cold start or low load conditions, the exhaust gas temperature is difficult to reach the efficient range of SCR. And when the diesel engine is in high load or regeneration conditions, the excessive exhaust gas temperature will accelerate the thermal aging of SCR, and the temperature of the tail gas is difficult to be effectively utilized.

[0003] For cold start or low load conditions, a method of electrically heating the catalyst has been proposed to improve the catalytic performance of the catalyst at low temperatures, but it requires additional energy consumption. For high load or regeneration conditions, mainly the structure and composition of the catalyst are improved to enhance the anti-aging performance of the catalyst, and there is no more direct solution. The present invention uses waste heat thermoelectric power generation of the tail gas, and realizes thermoelectric power generation through the characteristics of thermoelectric conversion devices using the heat of the vehicle exhaust gas, which can effectively save the fuel consumption of the vehicle and at the same time achieve the purpose of regulating the exhaust gas temperature. Summary of the Invention

[0004] Aiming at the deficiencies of the existing technology, the purpose of the present invention is to provide a device and method for regulating the active temperature of an SCR catalyst by using a thermoelectric power generation system, using waste heat of the tail gas for thermoelectric power generation to provide energy for the electric heating device, automatically regulating the temperature of the SCR device according to the exhaust gas temperature, and ensuring the ability of the SCR device to efficiently remove NO x without consuming additional energy.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions: The present invention provides a device for regulating the active temperature of an SCR catalyst by using a thermoelectric power generation system, including a thermoelectric power generation system. One end of the thermoelectric power generation system is connected to an exhaust pipe, and the other end is connected to an electric heating device. An SCR device is arranged on the side of the electric heating device away from the thermoelectric power generation system; the thermoelectric power generation system is connected to an engine cooling system through a cooling pipe and connected to a storage battery through a power supply module; the engine cooling system is also connected to an engine control unit, and the engine control unit is connected to the power supply module; a first temperature sensor is arranged between the thermoelectric power generation system and the electric heating device, and a second temperature sensor is arranged between the electric heating device and the SCR device.

[0006] Further, the thermoelectric power generation system includes a housing, a thermoelectric power generation plate and a cold-end radiator sequentially installed on both sides of the housing. The cold-end radiator is connected to the engine cooling system through a cooling pipe; a hot-end heat exchanger is arranged in the housing, and the hot-end heat exchanger is fixedly connected to the housing.

[0007] Further, the first temperature sensor is used to detect the inlet temperature of the electric heating device, and the second temperature sensor is used to detect the outlet temperature of the electric heating device.

[0008] Further, the power supply module includes a bidirectional DC / DC converter and an overload protection circuit, charges the storage battery through the thermoelectric power generation system; supplies power to the electric heating device through the storage battery.

[0009] Further, a resistance wire is arranged in the electric heating device to heat the exhaust gas temperature at the front end of the SCR device to above 200°C.

[0010] The present invention also provides a method for regulating the active temperature of an SCR catalyst by using a thermoelectric power generation system. Based on the above device for regulating the active temperature of an SCR catalyst by using a thermoelectric power generation system, it is characterized by including the following steps: The engine control unit monitors the temperature of the first temperature sensor; if the temperature of the first temperature sensor is less than 200°C, the generator control unit controls the power supply module to switch to the heating mode, and the storage battery is used as a power source to supply power to the electric heating device for heating; if the temperature of the first temperature sensor is greater than or equal to 200°C and less than 450°C, the generator control unit controls the power supply module to switch from the heating mode to the thermoelectric power generation mode; if the temperature of the first temperature sensor is greater than or equal to 450°C, the generator control unit controls the engine cooling system to increase the flow rate in the cold-end radiator of the thermoelectric power generation system to forcibly cool the thermoelectric power generation system.

[0011] Further, the generator control unit controls the power supply module to switch to the heating mode, including the following steps: obtaining the state of charge of the battery and determining whether the state of charge of the battery meets the discharge condition; if the state of charge of the battery meets the discharge condition, the engine control unit controls the power supply module to switch to the heating mode.

[0012] Further, after the generator control unit controls the power supply module to switch to the heating mode, the following steps are further included: obtaining the inlet and outlet temperatures of the electric heating device according to the first temperature sensor and the second temperature sensor; the generator control unit calculates the power required to heat the exhaust gas to 200 °C according to the inlet and outlet temperatures of the electric heating device and the power density; the power supply module controls the discharge power of the battery according to the power required to heat the exhaust gas to 200 °C.

[0013] Further, the generator control unit controls the power supply module to switch from the heating mode to the thermoelectric generation mode, including the following steps: obtaining the state of charge of the battery; determining whether the state of charge of the battery meets the discharge condition; if the state of charge of the battery meets the discharge condition, the generator control unit controls the power supply module to switch to the thermoelectric generation mode and controls the charging power according to the state of charge of the battery.

[0014] Further, after the generator control unit controls the power supply module to switch to the thermoelectric generation mode, the following steps are further included: the coolant of the engine cooling system enters the cold-end radiator in the thermoelectric generation system through the cooling pipeline for circulation, and the thermoelectric generation system charges the battery.

[0015] Compared with the prior art, the present invention has the following beneficial technical effects: The device for regulating the active temperature of the SCR catalyst by using the thermoelectric generation system according to the present invention effectively converts heat energy into electrical energy by using the temperature difference between the exhaust gas in the exhaust pipe and the engine coolant. It not only realizes the reuse of energy, but also helps to reduce the exhaust gas temperature and inhibit the thermal aging of the aftertreatment system. A part of the electrical energy generated by the thermoelectric generation system can be directly supplied to the battery for storage for emergencies; the other part can be used to drive the electric heating device to provide necessary heating for the exhaust gas at the inlet of the SCR device to ensure that the exhaust gas reaches the optimal activation temperature, usually above 200 °C, before entering the catalyst layer, so as to maximize the efficiency and effect of the catalytic reduction reaction.

[0016] A method for regulating the active temperature of an SCR catalyst using a thermoelectric power generation system according to the present invention. When the inlet exhaust gas temperature of the electric heating device is lower than 200 °C, the power supply module switches to the heating mode, and the storage battery provides power for the electric heating device. When the inlet exhaust gas temperature of the electric heating device is greater than or equal to 200 °C and less than 450 °C, it switches to the power generation mode, and the thermoelectric power generation system charges the storage battery. When the inlet exhaust gas temperature of the electric heating device is greater than or equal to 450 °C, the generator control unit controls the generator cooling system to increase the coolant flow rate to twice the original, forcibly increasing the heat dissipation of the thermoelectric power generation system and reducing the inlet exhaust gas temperature of the SCR device, so that the SCR catalyst always maintains an efficient working range. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural diagram of a device for regulating the active temperature of an SCR catalyst using a thermoelectric power generation system according to the present invention; Figure 2 It is a schematic structural diagram of the thermoelectric power generation system in an embodiment of the present invention.

[0018] REFERENCE SIGNS: 1 - exhaust pipe; 2 - thermoelectric power generation system; 21 - housing; 22 - thermoelectric power generation plate; 23 - cold end radiator; 3 - electric heating device; 4 - SCR device; 5 - cooling pipe; 6 - engine cooling system; 7 - power supply module; 8 - storage battery; 9 - engine control unit. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0020] Embodiment 1 A device for regulating the active temperature of an SCR catalyst using a thermoelectric power generation system according to the present invention includes a thermoelectric power generation system 2. One end of the thermoelectric power generation system 2 is connected to the exhaust pipe 1, and the other end is connected to the electric heating device 3. An SCR device 4 is arranged on the side of the electric heating device 3 away from the thermoelectric power generation system 2. The thermoelectric power generation system 2 is connected to the engine cooling system 6 through a cooling pipe 5 and is connected to the storage battery 8 through a power supply module 7. The engine cooling system 6 is also connected to the engine control unit 9, and the engine control unit 9 is connected to the power supply module 7. A first temperature sensor is arranged between the thermoelectric power generation system 2 and the electric heating device 3, and a second temperature sensor is arranged between the electric heating device 3 and the SCR device 4.

[0021] Specifically, as Figure 1 shown, the exhaust pipe 1 is sequentially connected to the thermoelectric power generation system 2, the electric heating device 3, and the SCR device 4 according to the exhaust gas emission order. A first temperature sensor is provided at the front end, i.e., the inlet of the electric heating device 3, and a second temperature sensor is provided at the front end of the SCR device. It further includes a power supply module 7, and the power supply module 7 is respectively connected to the thermoelectric power generation system 2, the generator control unit 9, the electric heating device 3, and the battery 8; the power supply module 7 is used to switch the power generation mode or the heating mode according to the data of the first temperature sensor. As Figure 2 shown, the thermoelectric power generation system 2 is composed of a housing 21, a thermoelectric power generation panel 22, and a cold-end radiator 23.

[0022] Utilizing the temperature difference between the exhaust gas in the exhaust pipe 1 and the coolant in the cold-end radiator 23, the thermal energy is effectively converted into electrical energy. It not only realizes the reuse of energy but also helps to reduce the exhaust gas temperature and inhibit the thermal aging of the post-treatment system. A part of the electrical energy generated by the thermoelectric power generation system 2 can be directly supplied to the battery 8 for storage in case of need; another part can be used to drive the electric heating device 3 to provide necessary heating for the exhaust gas at the inlet of the SCR device 4 to ensure that the exhaust gas reaches the optimal activation temperature, generally above 200 °C, before entering the catalyst layer, so as to maximize the efficiency and effect of the catalytic reduction reaction.

[0023] The thermoelectric power generation system 2 includes a housing 21, a thermoelectric power generation panel 22 and a cold-end radiator 23 sequentially installed on both sides of the housing 21, and the cold-end radiator 23 is connected to the engine cooling system 6 through a cooling pipe 5.

[0024] The inlet end of the housing 21 is communicated with the exhaust pipe 1, and the outlet end is communicated with the electric heating device 3 through a pipe. The first temperature sensor is installed in the pipe. The cold-end radiator 23 is connected to the generator cooling system 6 through the cooling pipe 5; the thermoelectric power generation panel 22 is electrically connected to the battery 8 through the power supply module 7, and the electric heating device 3 is connected to the battery 8 through the power supply module 7. It should be noted that both the first temperature sensor and the second temperature sensor are connected to the generator control unit 9.

[0025] The thermoelectric power generation principle of the thermoelectric power generation system 2 is as follows: The exhaust gas in the exhaust pipe 1 enters the thermoelectric power generation system 2, and the hot-end heat exchanger absorbs the heat of the exhaust gas; the coolant in the engine cooling system 6 circulates in the cold-end radiator 23 of the thermoelectric power generation system 2 through the cooling pipe 5, and electricity is generated according to the temperature difference between the hot-end heat exchanger and the cold-end radiator 23.

[0026] As Figure 2As shown in the figure, heat dissipation fins are provided on the hot end heat exchanger. The temperature of the exhaust gas directly affects the heat dissipation requirement of the hot end heat exchanger. When the exhaust gas temperature is high, in order to effectively dissipate heat and prevent the system from overheating, it is necessary to increase the number of heat dissipation fins, thereby increasing the heat dissipation area and improving the heat dissipation efficiency. An appropriate length of the heat dissipation fins can ensure that the heat of the exhaust gas is fully transferred and dissipated on the heat dissipation fins, while avoiding problems such as an increase in pressure drop and a decrease in heat dissipation efficiency caused by too long fins. Through reasonable length design, it can be ensured that the hot end heat exchanger can meet the heat dissipation requirement while maintaining low energy consumption and high working efficiency. The width of the heat dissipation fins can provide a larger heat dissipation area, which is conducive to the rapid dissipation of heat.

[0027] In summary, the number, length, and width of the heat dissipation fins are set according to the upper limit of the exhaust gas temperature in the exhaust pipe 1 and the upper limit of the SCR device temperature.

[0028] The power supply module 7 is provided with a bidirectional DC / DC converter and an overload protection circuit, so that the output power is greater than 1KW to support the power generation mode and the heat release mode. The thermoelectric generation of the thermoelectric generation system 2 charges the battery 8, and the battery 8 supplies power to the electric heating device 3.

[0029] The electric heating device 3 is provided with a resistance wire for heating the exhaust gas temperature in front of the SCR device 4 to above 200°C.

[0030] When the exhaust gas temperature is lower than 200°C, the electric heating device 3 is started, and the electric energy from the thermoelectric generation system 2 is used to heat the exhaust gas to an appropriate reaction temperature, thereby activating the catalyst and promoting the conversion of harmful substances such as NO x etc. When the exhaust gas temperature exceeds 450°C, the thermoelectric generation system 2 can adjust its working state and use the thermoelectric effect to assist in heat dissipation to help maintain the temperature stability inside the SCR device 4 and prevent the catalyst from being damaged due to overheating.

[0031] In addition, the electric heating device 3 is provided with a spiral heating wire for heating the exhaust gas temperature at the inlet of the SCR device. The heating wire generates heat through the action of an electric current, and this heat is quickly and evenly transferred to the exhaust gas flowing around it, so that the exhaust gas reaches the ideal reaction temperature range before entering the SCR device. The spiral heating wire can increase the contact area and time between the exhaust gas and the heating wire, thereby promoting the effective transfer of heat, helping to reduce energy loss during the heating process, and improving the thermal efficiency of the entire system.

[0032] In summary, the engine cooling system 6 is connected to the cold-end radiator 23 of the thermoelectric power generation system 2. The thermoelectric power generation panel 22 is connected to the storage battery 8 through the power supply module 7. The second temperature sensor is arranged at the outlet of the electric heating device 3. The first temperature sensor and the second temperature sensor are connected to the engine control unit 9. The engine control unit 9 is connected to the power supply module 7. The electric heating device 3 is connected to the storage battery 8 through the power supply module 7. The engine control unit 9 is used for controlling the charge and discharge of the storage battery 8. When the SCR device 4 is in the high-efficiency temperature range, the engine control unit 9 controls the power supply module 7 to charge the storage battery 8 by using the thermoelectric power generation system 2. When the SCR device 4 is outside the high-efficiency temperature range, the engine control unit 9 controls the power supply module 7 to discharge the storage battery 8 to the electric heating device 3 or controls the engine cooling system 6 to increase the supply of the coolant in the thermoelectric power generation system 2, so as to adjust the temperature of the SCR device 4 and improve the conversion efficiency of NOx and the energy utilization rate.

[0033] Embodiment 2 A method for regulating the active temperature of an SCR catalyst by using a thermoelectric power generation system includes the following steps: The engine control unit 9 monitors the temperature of the first temperature sensor. If the temperature detected by the first temperature sensor is less than 200 °C, the generator control unit 9 controls the power supply module 7 to switch to the heating mode, and the storage battery 8 supplies power to the electric heating device 3 for heating. If the temperature detected by the first temperature sensor is greater than or equal to 200 °C and less than 450 °C, the generator control unit 9 controls the power supply module 7 to switch from the heating mode to the thermoelectric power generation mode. If the temperature detected by the first temperature sensor is greater than or equal to 450 °C, the generator control unit 9 controls the engine cooling system 6 to cool down the thermoelectric power generation system 2.

[0034] Specifically, when the first temperature sensor detects that the exhaust gas at the inlet of the electric heating device 3 is lower than 200 °C, the generator control unit 9 controls the power supply module 7 to switch to the heating mode, and the storage battery 8 supplies power to the electric heating device 3 until the second temperature sensor detects that the exhaust gas temperature at the outlet of the electric heating device 3 is higher than 200 °C.

[0035] It should be noted that before the generator control unit controls the power supply module 7 to switch to the heating mode, it is also necessary to obtain the state of charge of the storage battery 8 and determine whether the state of charge of the storage battery 8 meets the discharge condition, so as to avoid the damage or performance degradation that may be caused by over-discharging of the storage battery 8. If the state of charge of the storage battery 8 meets the discharge condition, the mode conversion is carried out.

[0036] After switching to the heating mode, the first temperature sensor and the second temperature sensor acquire the inlet and outlet temperatures of the electric heating device 3, and the generator control unit 9 calculates the power required to heat the exhaust gas to 200°C based on the inlet and outlet temperatures of the electric heating device 3 and the power density; the power supply module 7 controls the discharge power of the battery 8 according to the power required to heat the exhaust gas to 200°C.

[0037] When the temperature of the first temperature sensor is greater than or equal to 200°C and less than 450°C, the generator control unit 9 controls the power supply module 7 to switch from the heating mode to the thermoelectric generation mode.

[0038] Specifically, when the temperature of the first temperature sensor is greater than or equal to 200°C, the generator control unit 9 controls the power supply module 7 to switch to the power generation mode, and the thermoelectric generation system 2 supplies power to the battery 8 until the battery 8 reaches 90% of its charge, and then the thermoelectric generation system 2 starts to supply power to other electrical devices of the vehicle.

[0039] It should be noted that before switching to the thermoelectric generation mode, it is also necessary to obtain the state of charge of the battery 8, determine whether the state of charge of the battery 8 meets the discharge condition. If it meets the discharge condition, then switch to the power generation mode, and control the charging power through the state of charge of the battery 8.

[0040] When the temperature of the first temperature sensor is greater than or equal to 450°C, the generator control unit 9 controls the engine cooling system 6 to cool down the thermoelectric generation system 2.

[0041] Specifically, when the first temperature sensor detects that the inlet exhaust gas temperature of the electric heating device 3 reaches above 450°C, the generator control unit 9 controls the engine cooling system 6 to increase the coolant flow rate in the cold-end radiator 23 of the thermoelectric generation system 2, improve the heat dissipation of the hot-end heat exchanger of the thermoelectric generation system 2 to reduce the temperature, until the first temperature sensor detects that the inlet exhaust gas temperature of the electric heating device 3 drops below 450°C and then the coolant flow rate is restored. It should be noted that when the first temperature sensor detects that the inlet exhaust gas temperature of the electric heating device 3 is above 450°C, the coolant flow rate is increased to twice the original.

[0042] The first temperature sensor is used to detect the inlet temperature of the electric heating device 3, and the second temperature sensor is used to detect the outlet temperature of the electric heating device 3.

[0043] In summary, when the inlet exhaust gas temperature of the electric heating device 3 is lower than 200 °C, the power supply module 7 switches to the heating mode, and the storage battery 8 supplies power to the electric heating device 3; when the inlet exhaust gas temperature of the electric heating device 3 is greater than or equal to 200 °C and less than 450 °C, it switches to the power generation mode, and the thermoelectric power generation system 2 charges the storage battery; when the inlet exhaust gas temperature of the electric heating device 3 is greater than or equal to 450 °C, the generator control unit 9 controls the generator cooling system 6 to increase the coolant flow rate to twice the original value, forcibly increasing the heat dissipation of the thermoelectric power generation system 2 and reducing the inlet exhaust gas temperature of the SCR device 4, so that the SCR catalyst always maintains in the efficient working range.

[0044] It should be noted that the terms "first", "second", etc. in the description, claims and above-mentioned drawings of the present invention are used to distinguish similar objects, and do not necessarily need to be used to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances, so that the embodiments of the present invention described here can be implemented in an order other than those illustrated or described here. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device comprising a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

Claims

1. A device for adjusting the active temperature of an SCR catalyst using a temperature difference power generation system, characterized in that: The invention comprises a temperature difference power generation system (2), one end of the temperature difference power generation system (2) being connected to an exhaust pipe (1), and the other end being connected to an electric heating device (3), wherein an SCR device (4) is arranged on a side of the electric heating device (3) away from the temperature difference power generation system (2); the temperature difference power generation system (2) is connected to an engine cooling system (6) via a cooling pipe (5), and is connected to a battery (8) via a power supply module (7); the engine cooling system (6) is also connected to an engine control unit (9), and the engine control unit (9) is connected to the power supply module (7); A first temperature sensor is provided between the temperature difference power generation system (2) and the electric heating device (3), and a second temperature sensor is provided between the electric heating device (3) and the SCR device (4).

2. The device for adjusting the active temperature of the SCR catalyst using a temperature difference power generation system according to claim 1, characterized in that: The temperature difference power generation system (2) comprises a housing (21), a temperature difference power generation plate (22) and a cold end radiator (23) which are sequentially mounted on both sides of the housing (21), and the cold end radiator (23) is connected to an engine cooling system (6) via a cooling pipe (5); A hot end heat exchanger is arranged in the shell (21), and the hot end heat exchanger is fixedly connected to the shell (21).

3. The device for adjusting the active temperature of the SCR catalyst using a temperature difference power generation system according to claim 1, characterized in that: The first temperature sensor is used to detect the inlet temperature of the electric heating device (3), and the second temperature sensor is used to detect the outlet temperature of the electric heating device (3).

4. The device for adjusting the active temperature of the SCR catalyst using a temperature difference power generation system according to claim 3, characterized in that: The power supply module (7) comprises a bidirectional DC / DC converter and an overload protection circuit, and charges the storage battery (8) through the temperature difference power generation system (2); and supplies power to the electric heating device (3) through the storage battery (8).

5. The device for adjusting the active temperature of the SCR catalyst using a temperature difference power generation system according to claim 1, characterized in that: The electric heating device (3) is provided with a resistance wire for heating the exhaust gas temperature at the front end of the SCR device (4) to above 200°C.

6. A method for adjusting the active temperature of an SCR catalyst using a thermoelectric power generation system, based on the device for adjusting the active temperature of an SCR catalyst using a thermoelectric power generation system according to any one of claims 1 to 5, characterized in that: The following steps are involved: The engine control unit (9) monitors the temperature of the first temperature sensor; If the temperature of the first temperature sensor is less than 200° C., the generator control unit (9) controls the power supply module (7) to switch to a heating mode, and the storage battery (8) serves as a power source to supply power to the electric heating device (3) and perform heating; If the temperature of the first temperature sensor is greater than or equal to 200° C. and less than 450° C., the generator control unit (9) controls the power supply module (7) to switch from a heating mode to a temperature difference power generation mode; If the temperature of the first temperature sensor is greater than or equal to 450° C., the generator control unit (9) controls the engine cooling system (6) to increase the flow rate in the cold end radiator (23) to force cooling of the temperature difference power generation system (2).

7. The method for adjusting the active temperature of the SCR catalyst using a temperature difference power generation system according to claim 6, characterized in that: The generator control unit (9) controls the power supply module (7) to switch to a heating mode, comprising the following steps: Obtaining the state of charge of the storage battery (8), and determining whether the state of charge of the storage battery (8) satisfies a discharge condition; If the charge state of the storage battery (8) meets the discharge condition, the engine control unit (9) controls the power supply module (7) to switch to the heating mode.

8. The method for adjusting the active temperature of the SCR catalyst using a temperature difference power generation system according to claim 6, characterized in that: After the generator control unit (9) controls the power supply module (7) to switch to the heating mode, the following steps are also included: Acquiring the inlet and outlet temperatures of the electric heating device (3) according to the first temperature sensor and the second temperature sensor; The generator control unit (9) calculates the power required to heat the exhaust gas to 200° C. according to the inlet and outlet temperatures and the power density of the electric heating device (3); The power supply module (7) controls the discharge power of the storage battery (8) according to the power required to heat the exhaust gas to 200°C.

9. The method for adjusting the active temperature of the SCR catalyst using a temperature difference power generation system according to claim 8, characterized in that: The generator control unit (9) controls the power supply module (7) to switch from a heating mode to a temperature difference power generation mode, comprising the following steps: Obtaining the state of charge of the battery (8); Determining whether the state of charge of the battery (8) satisfies a discharge condition; If the charge state of the storage battery (8) meets the discharge condition, the generator control unit (9) controls the power supply module (7) to switch to the temperature difference power generation mode, and controls the charging power according to the charge state of the storage battery (8).

10. The method for adjusting the active temperature of the SCR catalyst using a temperature difference power generation system according to claim 9, characterized in that: After the generator control unit (9) controls the power supply module (7) to switch to the temperature difference power generation mode, the following steps are also included: The coolant of the engine cooling system (6) enters the cold end radiator (23) in the temperature difference power generation system (2) through the cooling pipe (5) for circulation, and the temperature difference power generation system (2) charges the storage battery (8).

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