Vehicle post-treatment vortex heating regeneration system and method

Abstract

The invention provides an after-treatment vortex heating regeneration system and method for a vehicle. A TWC three-way catalyst, a GPF particle trap and an electric heating system located between the TWC three-way catalyst and the GPF particle trap are arranged in a shell of the vortex heating regeneration system; the electric heating system comprises conical heating surfaces and cylindrical heating surfaces, the conical heating surfaces are concentrically arranged and fixedly supported through an inner supporting plate, the cylindrical heating surfaces are flush with the conical heating surfaces with different diameters and fixedly connected with the conical heating surfaces with the different diameters, and the free ends of the conical heating surfaces and the free ends of the cylindrical heating surfaces are fixed to a heating surface support. The heating surface bracket is fixed on the shell; a ceramic coating is arranged on the surface of the conical heating face on the outermost layer to serve as a ceramic support, an eddy current heating coil is embedded in the ceramic support, and leads on the two sides of the eddy current heating coil penetrate through the shell in a bent mode and are connected into an electromagnetic heating controller located outside the shell. When an automobile runs at a low rotating speed for a long time, the vortex heating regeneration system can timely increase the temperature of tail gas flow.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle emissions, and particularly relates to a vortex heating regeneration system and method for vehicle post-treatment. Background Art

[0002] With the increasingly stringent motor vehicle emission regulations, in view of the tightened limit requirements for pollutants such as NO X , CO, and PM in the Euro 7 standard to meet ultra-low emissions, in order to meet the international requirements, in the near future, domestic emission requirements will also be tightened synchronously.

[0003] The principle of the gasoline particulate filter (GPF) seems perfect. By intercepting carbon particles in the exhaust gas through a honeycomb ceramic structure, theoretically, 90% of the pollution can be reduced. However, in actual situations, urban short-distance commuting vehicle owners are the first to be affected. Since the GPF needs to burn the accumulated carbon at a high temperature (about 600°C) to complete "regeneration", frequent low-speed driving leads to particle accumulation, resulting in a significant increase in fuel consumption in the light case and a power attenuation like "stepping on cotton" in the severe case. Currently, the solution of many vehicle manufacturers is to let the vehicle owners "regularly drive on the highway to burn carbon", which undoubtedly increases the vehicle use cost of users and does not conform to the concept of energy conservation and environmental protection advocated by the country. Therefore, it is necessary to optimize and improve the existing GPF technology.

[0004] For short-distance commuters (daily mileage < 20 km), due to frequent ultra-short trips, the engine may not have enough time to fully warm up, the gasoline burns incompletely, and the exhaust temperature is not high enough to burn and discharge the particles in the GPF, resulting in GPF blockage. In addition, low-temperature operation is also a major factor causing GPF blockage, especially in winter or low-temperature regions, where the GPF may not reach the operating temperature, leading to a large amount of carbon deposition.

[0005] Under the current technical conditions, the adoption of an electric heating device in the exhaust system has become one of the main research directions of major vehicle manufacturers and OEMs. It is necessary to quickly reach the ignition temperature of the catalytic converter in the exhaust gas to remove the accumulated carbon inside the GPF. However, due to the current electric heating principle mainly being resistance type such as electric heating sheets and electric heating coils, there is a problem of low thermal efficiency generated by heat conduction, and it is difficult for the gas temperature to quickly reach the ignition temperature of the catalytic converter.

[0006] In addition, the electric heating coil wound by the resistance wire has a large thermal lag, is not easy to accurately control the temperature, and the resistance wire is easily burned out due to high-temperature aging. The commonly used electric heating coil has a short service life, so the maintenance workload is relatively large. In addition, the void characteristics of the resistance wire cannot make the most of the heating source area, resulting in the heating efficiency not being maximized. Summary of the Invention

[0007] The object of the present invention is to overcome the deficiencies existing in the prior art and provide a vehicle post-treatment eddy current heating regeneration system and method, aiming to enable the vehicle to timely increase the tail gas flow temperature and quickly activate the regeneration function when the engine runs at a low speed for a long time in a low-temperature environment and on urban roads.

[0008] To achieve the above technical objectives, the technical solutions adopted in the embodiments of the present invention are as follows: In a first aspect, an embodiment of the present invention provides a vehicle post-treatment eddy current heating regeneration system, including a housing. Inside the housing, there are a TWC three-way catalyst and a GPF particulate filter, and an electric heating system is arranged between the TWC three-way catalyst and the GPF particulate filter. The electric heating system includes a conical heating surface and a cylindrical heating surface. A number of conical heating surfaces with different diameters are concentrically arranged and fixed and supported by inner support plates. A number of cylindrical heating surfaces are respectively aligned with and fixedly connected to the conical heating surfaces with different diameters. The free ends of the conical heating surface and the cylindrical heating surface are respectively fixed on a heating surface bracket, and the heating surface bracket is fixed on the housing. On the surface of the outermost conical heating surface, there is a ceramic coating as a ceramic bracket, and an eddy current heating coil is embedded in the ceramic bracket. The leads on both sides of the eddy current heating coil pass through the housing by bending and are connected to an electromagnetic heating controller located outside the housing.

[0009] Further, the housing includes an outer housing and an inner housing. A TWC catalyst gasket is arranged between the TWC three-way catalyst and the outer housing, and a GPF carrier gasket is arranged between the GPF particulate filter and the outer housing. The inner housing is only arranged between the heating surface brackets, and the heating surface brackets are fixedly connected to the inner housing. Heat insulation cotton is arranged between the outer housing and the inner housing.

[0010] Further, the electromagnetic heating controller is arranged on a mounting bracket, the mounting bracket is mounted on a heat insulation bracket, and the heat insulation bracket is welded to the outer housing.

[0011] Further, the outer layer of the eddy current heating coil is wrapped with a high-temperature resistant insulating material, and the temperature resistance is greater than 800 °C.

[0012] Further, the first end of the conical heating surface is arranged close to the TWC three-way catalyst, the second end of the conical heating surface is fixedly connected to the cylindrical heating surface, and the diameters of the connected conical heating surface and the cylindrical heating surface are the same. The diameter of the first end of the conical heating surface is smaller than the diameter of the second end of the conical heating surface.

[0013] Further, the taper of the conical heating surface is 30°-45°, the length is 150-200 mm, and the tapers of the concentrically arranged conical heating surfaces are the same; The inner diameter d of the inner shell satisfies the following condition: nt < d / 3, where n is the number of conical heating surfaces and / or cylindrical heating surfaces, and t is the thickness of the conical heating surface and / or cylindrical heating surface, where 1.5 mm ≤ t ≤ 2.5 mm; Both the conical heating surface and the cylindrical heating surface are made of 3-series or 4-series stainless steel alloys.

[0014] Further, a temperature sensor is provided at the front section of the GPF particulate trap. The temperature sensor is used to detect the temperature T of the gas flow heated by the electric heating system and transmit the temperature signal to the electromagnetic heating controller. The electromagnetic heating controller controls the start and stop of the electric heating system according to the temperature signal.

[0015] Further, differential pressure sensors are provided at both ends of the GPF particulate trap. The differential pressure sensors are used to detect the pressure difference △P at both ends of the GPF particulate trap and transmit the differential pressure signal to the electromagnetic heating controller. The electromagnetic heating controller controls the start and stop of the electric heating system according to the differential pressure signal. Further, the heating surface support includes an outer ring surface, an inner ring surface, and a support. The supports are evenly distributed between the outer ring surface and the inner ring surface, and the outer ring surface and the inner ring surface are concentrically arranged. The outer ring surface is fixedly connected to the inner shell.

[0016] In a second aspect, an embodiment of the present invention provides a method for post-treatment eddy current heating regeneration for vehicles, which is carried out on the post-treatment eddy current heating regeneration system described in the first aspect, and includes the following steps: Step S1: When the engine is cold-started, after receiving the ECU ignition signal, the electromagnetic heating controller synchronously turns on the electric heating system. After the eddy current heating coil is energized, a magnetic field is generated, and the gas flow passing through the conical heating surface and the inside of the cylindrical heating surface is quickly heated up; Step S2: When the vehicle mileage L < 2000 km, collect the temperature T of the temperature sensor: when T < 250 °C, the electric heating system heats at a 50% drive duty ratio; when T ≥ 400 °C, the electric heating system stops heating; When the vehicle mileage L ≥ 2000 km, collect the differential pressure △P of the differential pressure sensor: when 5 kPa ≤ △P < 20 kPa, the electric heating system heats at an 80% drive duty ratio, raises the temperature T at the rear end of the DOC to 600-610 °C and maintains it to promote the regeneration function of the GPF and remove carbon particles; When △P ≥ 20 kPa, the electric heating system heats at a 100% driving duty cycle, raising the temperature T at the rear end of the DOC to 600 - 610 °C and maintaining it to promote the regeneration function of the GPF and remove carbon particulate matter. Step S3: When the continuous heating time reaches 10 minutes, read the pressure difference △P again. If △P < 5 kPa, the electric heating system stops heating. If 5 kPa ≤ △P < 20 kPa, repeat the above heating operation.

[0017] The beneficial effects brought by the technical solution provided in the embodiment of the present invention are as follows: 1. The eddy current heating regeneration system of the present invention uses electromagnetic induction heating, which has the advantages of fast heating speed, energy conservation and environmental protection, safety and reliability, etc. Compared with traditional heating methods, the electromagnetic induction heating frequency converter can heat the heating body to the required temperature faster and can achieve precise temperature control, avoiding problems such as low heat transfer efficiency and energy waste existing in the traditional heating air flow method.

[0018] 2. Changing the traditional electric heating wire heating method to the electromagnetic induction eddy current heating method, compared with resistance heating, the heating speed of the electromagnetic heater is more than one - quarter faster, reducing the heating time and increasing the heat transfer efficiency of the air flow.

[0019] 3. The method of combining the conical eddy current coil with the conical heating surface increases the heating area of the air flow, effectively avoiding the void characteristics of the existing electric heaters that generally use electric heating wires, enabling the air flow to be fully heated and raised in temperature; designing the eddy current coil to be conical can increase the over - heated area of the air flow.

[0020] 4. The eddy current heating regeneration system of the present invention sets a heating zone between the TWC section and the GPF section, enabling the TWC and the GPF to be heated simultaneously, which can raise the air flow temperature, quickly reach the regeneration temperature condition for the GPF bed temperature, play a positive role in the regeneration function, make up for the problem that passive regeneration does not work under low - temperature conditions, save the fuel required for active regeneration, achieve the effect of energy conservation and emission reduction, and can avoid the problem that the air flow cannot reach the reaction temperature during short - distance driving.

[0021] 5. The eddy current heating regeneration system of the present invention buries the eddy current coil in the ceramic, effectively ensuring the stability and reliability of the heating coil, enabling the heating system to have excellent impact resistance. When the carbon loading is relatively high, it can increase the heating current and quickly raise the temperature to 600 - 610 °C to replace the injection of fuel to play the function of active regeneration. Description of the Drawings

[0022] Figure 1 It is a schematic structural diagram of the vehicle post - treatment eddy current heating regeneration system in the embodiment of the present invention.

[0023] Figure 2 This is a sectional view of the vehicle post-treatment eddy current heating regeneration system in the embodiment of the present invention.

[0024] Figure 3 It is Figure 1 A schematic structural diagram of the eddy current heating coil in the vehicle post-treatment eddy current heating regeneration system.

[0025] Figure 4 It is Figure 1 A schematic structural diagram of the ceramic support in the vehicle post-treatment eddy current heating regeneration system.

[0026] Figure 5 It is Figure 1 A schematic structural diagram of the conical heating surface in the vehicle post-treatment eddy current heating regeneration system.

[0027] Figure 6 It is Figure 1 A schematic structural diagram of the heating surface support in the vehicle post-treatment eddy current heating regeneration system.

[0028] Explanation of reference numerals: 1 - TWC three-way catalyst; 2 - ceramic support; 3 - heat insulation support; 4 - electromagnetic heating controller; 5 - mounting support; 6 - cylindrical heating surface; 7 - GPF particulate trap; 8 - GPF carrier gasket; 9 - heating surface support; 10 - heat insulation cotton; 11 - eddy current heating coil; 12 - inner support plate; 13 - outer housing; 14 - TWC catalyst gasket; 15 - conical heating surface; 16 - inner housing; 17 - temperature sensor; 18 - differential pressure sensor; 91 - outer ring surface; 92 - inner ring surface; 93 - support. Detailed implementation manners

[0029] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by orientation words such as "inside, outside", "up, down", "left, right", etc. is usually based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description. Without contrary description, these orientation words do not indicate and imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as limiting the protection scope of the present invention.

[0030] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0031] Embodiment 1 As Figure 1-4As shown in the figure, a vehicle post-treatment eddy current heating regeneration system includes a housing. Inside the housing, a TWC three-way catalyst 1 and a GPF particulate trap 7 are provided. An electric heating system is arranged between the TWC three-way catalyst 1 and the GPF particulate trap 7. The electric heating system includes a conical heating surface 15 and a cylindrical heating surface 6. A number of conical heating surfaces 15 with different diameters are concentrically arranged and fixedly supported by an inner support plate 12. A number of cylindrical heating surfaces 6 are respectively aligned and fixedly connected with the conical heating surfaces 15 with different diameters. The free ends of the conical heating surface 15 and the cylindrical heating surface 6 are respectively fixed on a heating surface support 9, and the heating surface support 9 is fixed on the housing. On the surface of the outermost conical heating surface 15, a ceramic coating with a thickness of 1 - 1.5 cm is provided as a ceramic support 2. An eddy current heating coil 11 is embedded in the ceramic support 2. The leads on both sides of the eddy current heating coil 11 pass through the housing in a bent manner and are connected to an electromagnetic heating controller 4 located outside the housing.

[0032] The housing includes an outer housing 13 and an inner housing 16. A TWC catalyst gasket 14 is arranged between the TWC three-way catalyst 1 and the outer housing 13, and a GPF carrier gasket 8 is arranged between the GPF particulate trap 7 and the outer housing 13. The inner housing 16 is only arranged between the heating surface supports 9, and the heating surface supports 9 are fixedly connected to the inner housing 16. An insulating cotton 10 is arranged between the outer housing 13 and the inner housing 16.

[0033] The electromagnetic heating controller 4 is arranged on a mounting bracket 5, the mounting bracket 5 is mounted on a heat insulation bracket 3, and the heat insulation bracket 3 is welded to the outer housing 13.

[0034] The outer layer of the eddy current heating coil 11 is wrapped with a high-temperature resistant insulating material, and the temperature resistance is greater than 800 °C. As an implementation method, the high-temperature resistant insulating material is made of alumina ceramic.

[0035] As Figure 5 shown in the figure, the first end of the conical heating surface 15 is arranged close to the TWC three-way catalyst 1, the second end of the conical heating surface 15 is fixedly connected to the cylindrical heating surface 6, and the diameters of the connected conical heating surface 15 and the cylindrical heating surface 6 are the same. The diameter of the first end of the conical heating surface 15 is smaller than the diameter of the second end of the conical heating surface 15.

[0036] The taper of the conical heating surface 15 is 30° - 45°, and the length is 150 - 200 mm. The tapers of the concentrically arranged conical heating surfaces 15 are the same. The inner diameter d of the inner housing 16 satisfies the following condition: nt < d / 3, where n is the number of the conical heating surface 15 and the cylindrical heating surface 6, and t is the thickness of the conical heating surface 15 and the cylindrical heating surface 6, where 1.5 mm ≤ t ≤ 2.5 mm. As an implementation, n = 4 and t = 2.0 mm.

[0037] Both the conical heating surface 15 and the cylindrical heating surface 6 are made of 3-series or 4-series stainless steel alloys.

[0038] A temperature sensor 17 is provided at the front section of the GPF particulate trap 7. The temperature sensor 17 is used to detect the temperature T of the air flow heated by the electric heating system and transmit the temperature signal to the electromagnetic heating controller 4. The electromagnetic heating controller 4 controls the start and stop of the electric heating system according to the temperature signal.

[0039] Differential pressure sensors 18 are provided at both ends of the GPF particulate trap 7. The differential pressure sensors 18 are used to detect the pressure difference ΔP at both ends of the GPF particulate trap 7 and transmit the differential pressure signal to the electromagnetic heating controller 4. The electromagnetic heating controller 4 controls the start and stop of the electric heating system according to the differential pressure signal. As Figure 6 As shown, the heating surface support 9 includes an outer ring surface 91, an inner ring surface 92, and supports 93. The supports 93 are evenly distributed between the outer ring surface 91 and the inner ring surface 92, and the outer ring surface 91 and the inner ring surface 92 are concentrically arranged. The outer ring surface 91 is fixedly connected to the inner housing 16.

[0040] Embodiment 2 A vehicle post-treatment eddy current heating regeneration method is carried out on the above vehicle post-treatment eddy current heating regeneration system, including the following steps: Step S1: When the engine is cold-started, after the electromagnetic heating controller 4 receives the ECU ignition signal, the electric heating system is synchronously turned on. After the eddy current heating coil 11 is energized, a magnetic field is generated, and the air flow passing through the conical heating surface 15 and the cylindrical heating surface 6 is quickly heated up. Step S2: When the vehicle mileage L < 2000 km, collect the temperature T of the temperature sensor 17: When T < 250 °C, the electric heating system heats with a 50% drive duty ratio; when T ≥ 400 °C, the electric heating system stops heating. When the vehicle mileage L ≥ 2000 km, collect the differential pressure ΔP of the differential pressure sensor 18: When 5 kPa ≤ ΔP < 20 kPa, the electric heating system heats with an 80% drive duty ratio, raises the temperature T at the rear end of the DOC to 600 - 610 °C and maintains it to promote the regeneration function of the GPF and remove carbon particles. When ΔP ≥ 20 kPa, the electric heating system heats with a 100% drive duty ratio, raises the temperature T at the rear end of the DOC to 600 - 610 °C and maintains it to promote the regeneration function of the GPF and remove carbon particles. Step S3: When the continuous heating time reaches 10 min, read the pressure difference △P again. If △P < 5 kPa, the electric heating system stops heating. If 5 kPa ≤ △P < 20 kPa, repeat the above heating operation.

[0041] The eddy current heating regeneration system of the present invention sets a heating zone between the TWC section and the GPF section, so that the TWC and the GPF are heated simultaneously, which can increase the gas flow temperature, enable the GPF bed temperature to quickly reach the regeneration temperature condition, play a positive role in the regeneration function, make up for the problem that passive regeneration does not work under low-temperature conditions, save the fuel required for active regeneration, achieve the effect of energy conservation and emission reduction, and can avoid the problem that the gas flow cannot reach the reaction temperature during short-distance driving.

[0042] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention and are not restrictive. Although the present invention has been described in detail with reference to the examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A vehicle post-treatment eddy current heating regeneration system, characterized in that It includes a housing, inside which a TWC three-way catalyst (1) and a GPF particulate trap (7) are provided, and an electric heating system is arranged between the TWC three-way catalyst (1) and the GPF particulate trap (7). The electric heating system includes a conical heating surface (15) and a cylindrical heating surface (6). A number of conical heating surfaces (15) with different diameters are concentrically arranged and fixedly supported by an inner support plate (12). A number of cylindrical heating surfaces (6) are respectively aligned with and fixedly connected to the conical heating surfaces (15) with different diameters. The free ends of the conical heating surface (15) and the cylindrical heating surface (6) are respectively fixed on a heating surface support (9), and the heating surface support (9) is fixed on the housing. A ceramic coating is provided on the surface of the outermost conical heating surface (15) as a ceramic support (2), and an eddy current heating coil (11) is embedded in the ceramic support (2). The leads on both sides of the eddy current heating coil (11) pass through the housing in a bent manner and are connected to an electromagnetic heating controller (4) located outside the housing.

2. The vehicle post-treatment eddy current heating regeneration system according to claim 1, wherein, The housing includes an outer housing (13) and an inner housing (16). A TWC catalyst gasket (14) is arranged between the TWC three-way catalyst (1) and the outer housing (13), and a GPF carrier gasket (8) is arranged between the GPF particulate trap (7) and the outer housing (13). The inner housing (16) is only provided between the heating surface supports (9), and the heating surface supports (9) are fixedly connected to the inner housing (16). Heat insulation cotton (10) is arranged between the outer housing (13) and the inner housing (16).

3. The vehicle post-treatment eddy current heating regeneration system according to claim 2, characterized in that, The electromagnetic heating controller (4) is arranged on a mounting bracket (5), the mounting bracket (5) is mounted on a heat insulation bracket (3), and the heat insulation bracket (3) is welded to the outer housing (13).

4. The vehicle post-treatment eddy current heating regeneration system according to claim 1, wherein, The outer layer of the eddy current heating coil (11) is wrapped with a high-temperature resistant insulating material, and the temperature resistance is greater than 800 °C.

5. The vehicle post-treatment eddy current heating regeneration system according to claim 1, characterized in that, The first end of the conical heating surface (15) is arranged close to the TWC three-way catalyst (1), the second end of the conical heating surface (15) is fixedly connected to the cylindrical heating surface (6), and the diameters of the connected conical heating surface (15) and the cylindrical heating surface (6) are the same. The diameter of the first end of the conical heating surface (15) is smaller than the diameter of the second end of the conical heating surface (15).

6. The vehicle post-treatment eddy current heating regeneration system according to claim 2, wherein The taper of the conical heating surface (15) is 30° - 45°, the length is 150 - 200 mm, and the tapers of the concentrically arranged conical heating surfaces (15) are the same. The inner diameter d of the inner housing (16) satisfies the following condition: nt < d / 3, where n is the number of the conical heating surface (15) and / or the cylindrical heating surface (6), and t is the thickness of the conical heating surface (15) and / or the cylindrical heating surface (6), where 1.5 mm ≤ t ≤ 2.5 mm. Both the conical heating surface (15) and the cylindrical heating surface (6) are made of 3-series or 4-series stainless steel alloy.

7. The vehicle post-treatment eddy current heating regeneration system according to claim 1, wherein A temperature sensor (17) is provided at the front section of the GPF particulate trap (7). The temperature sensor (17) is used to detect the temperature T of the air flow heated by the electric heating system and transmit a temperature signal to the electromagnetic heating controller (4). The electromagnetic heating controller (4) controls the start and stop of the electric heating system according to the temperature signal.

8. The vehicular post-treatment eddy current heating regeneration system according to claim 1, wherein, Differential pressure sensors (18) are provided at both ends of the GPF particulate trap (7). The differential pressure sensors (18) are used to detect the pressure difference △P at both ends of the GPF particulate trap (7) and transmit a differential pressure signal to the electromagnetic heating controller (4). The electromagnetic heating controller (4) controls the start and stop of the electric heating system according to the differential pressure signal.

9. The vehicle post-treatment eddy current heating regeneration system according to claim 2, wherein The heating surface support (9) includes an outer ring surface (91), an inner ring surface (92), and a support (93). The supports (93) are evenly distributed between the outer ring surface (91) and the inner ring surface (92), and the outer ring surface (91) and the inner ring surface (92) are concentrically arranged. The outer ring surface (91) is fixedly connected to the inner housing (16).

10. A post-treatment eddy current heating regeneration method for vehicles, characterized in that, It is carried out on the vehicle post-treatment eddy current heating regeneration system according to any one of claims 1-9, including the following steps: Step S1: When the engine is cold-started, after the electromagnetic heating controller (4) receives the ECU ignition signal, the electric heating system is synchronously turned on. After the eddy current heating coil (11) is energized, a magnetic field is generated, and the air flow passing through the conical heating surface (15) and the inside of the cylindrical heating surface (6) is rapidly heated. Step S2: When the vehicle mileage L < 2000 km, the temperature T of the temperature sensor (17) is collected. When T < 250 °C, the electric heating system is heated at a drive duty ratio of 50%. When T ≥ 400 °C, the electric heating system stops heating. When the vehicle mileage L ≥ 2000 km, the differential pressure △P of the differential pressure sensor (18) is collected. When 5 kPa ≤ △P < 20 kPa, the electric heating system is heated at a drive duty ratio of 80%, raising the temperature T at the rear end of the DOC to 600-610 °C and maintaining it to promote the regeneration function of the GPF and remove carbon particles. When △P ≥ 20 kPa, the electric heating system is heated at a drive duty ratio of 100%, raising the temperature T at the rear end of the DOC to 600-610 °C and maintaining it to promote the regeneration function of the GPF and remove carbon particles. Step S3: When the continuous heating time reaches 10 min, the differential pressure value △P is read again. If △P < 5 kPa, the electric heating system stops heating. If 5 kPa ≤ △P < 20 kPa, the above heating operation is repeated.

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