An engine cooling system and control method

Abstract

This application relates to an engine cooling system and control method, belonging to the field of engine cooling technology. The system includes an engine with an exhaust manifold, a turbine, an intercooler, a main compressor, an intake manifold, a fan clutch, and a main cooling fan connected to the fan clutch. The exhaust manifold is connected to the turbine, the main compressor is coaxially connected to the turbine, and the main compressor is connected to the intercooler. The intercooler cools the compressed air from the main compressor before it is introduced into the intake manifold. The system also includes an electronic control unit (ECU), a secondary compressor coaxially connected to the turbine, and an air cooling device connected to the secondary compressor via cooling pipes. The air cooling device is installed on high-temperature components of the engine. A flow control valve is installed on the cooling pipes, and a temperature sensor is installed on the engine. The ECU is electrically connected to the fan clutch, the temperature sensor, and the flow control valve. This application can reduce the load on the main cooling fan and improve engine fuel economy.

Description

Technical Field

[0001] This invention relates to the field of engine cooling technology, and in particular to an engine cooling system and control method. Background Technology

[0002] Engine cooling systems typically include a coolant circulation loop and a main cooling fan. The main cooling fan is driven by the engine crankshaft via a belt or motor, consuming power from engine accessories and generating significant aerodynamic noise at high speeds. Traditional control strategies mostly rely on directly adjusting the fan speed based on coolant or engine body temperature to dissipate heat; this is the most common solution in the field. In recent years, solutions utilizing exhaust gas energy to drive cooling devices have emerged. For example, there is a dual-compressor turbocharger structure where the boosted air from the auxiliary compressor is cooled before entering the engine cylinders, but its purpose is not heat dissipation, but rather combustion optimization. This patent does not address the coordinated control with the main cooling fan.

[0003] The prior art CN2926532Y discloses an intercooling system for an automotive engine. This system collects various relevant technical parameters through sensors installed within the system and feeds them back to the program controller. However, the ultimate control object of this system is still the fan itself, failing to break free from the mindset of adjusting the fan. Furthermore, its cooling energy comes entirely from the power of engine accessories (fan consumption) and does not involve the recovery and utilization of exhaust gas energy. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide an engine cooling system and control method to solve the problems of high power consumption and high noise caused by simply relying on adjusting the fan speed in the prior art.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: an engine cooling system, including an engine, the engine having an exhaust manifold, a turbine, an intercooler, a main compressor, an intake manifold, a fan clutch, and a main cooling fan connected to the fan clutch. The exhaust manifold is connected to the turbine, the main compressor is coaxially connected to the turbine, and the main compressor is connected to the intercooler. The intercooler is used to cool the compressed air from the main compressor before inputting it into the intake manifold. The system also includes an electronic control unit, an auxiliary compressor coaxially connected to the turbine, and an air cooling device connected to the auxiliary compressor through a cooling pipe. The air cooling device is installed on the high-temperature components of the engine, and a flow control valve is provided on the cooling pipe. The auxiliary compressor is used to input compressed air into the air cooling device, and the air cooling device is used to perform air cooling on the high-temperature components of the engine to achieve engine cooling. The engine is equipped with a temperature sensor for detecting engine temperature, and the electronic control unit is electrically connected to the fan clutch, the temperature sensor and the flow control valve.

[0006] As a preferred embodiment, the engine is further provided with an exhaust pipe connected to the exhaust manifold and an intake pipe connected to the intake manifold. The exhaust pipe is connected to the turbine, and the intake pipe is connected to the intercooler. Both the main compressor and the auxiliary compressor are centrifugal compressors.

[0007] As a preferred embodiment, the high-temperature components of the engine include at least one of the following: cylinder head, exhaust manifold, turbine housing, and EGR cooler housing.

[0008] As a preferred embodiment, the temperature sensor is mounted on the exhaust manifold or turbine housing.

[0009] As a preferred embodiment, the main cooling fan is an electronically controlled silicone oil clutch fan, an electronically controlled electromagnetic clutch fan, or an electronic fan, and the electronic control unit controls the speed of the main cooling fan through the fan clutch.

[0010] As a preferred embodiment, the system also includes an air storage tank, and the cooling pipeline includes a first sub-pipeline and a second sub-pipeline. The auxiliary compressor is connected to the air inlet of the air storage tank through the first sub-pipeline, and the air cooling device is connected to the air outlet of the air storage tank through the second sub-pipeline. A pressure regulating valve is provided at the air outlet of the air storage tank. The pressure regulating valve is used to provide compressed air at a constant pressure to the air cooling device, and a flow control valve is provided on the second sub-pipeline.

[0011] As a preferred embodiment, the air cooling device includes an air cooling pipe and a cooling intake pipe connected to the air cooling pipe. The cooling intake pipe is connected to a second sub-pipe. The air cooling pipe is provided with an air outlet gap. Compressed air from the auxiliary compressor is injected through the air outlet gap of the air cooling pipe. After the air cooling pipe is entrained by ambient air around the air cooling pipe to form a mixed airflow, it is blown toward the high-temperature components of the engine to achieve air cooling of the high-temperature components of the engine.

[0012] As a preferred embodiment, the air cooling pipe has an outer side wall and an inner side wall, forming an air supply chamber between the outer side wall and the inner side wall. An air outlet gap communicates with the air supply chamber. The inner side wall has an inwardly recessed flange that extends into the air supply chamber. The outer side wall has an outwardly recessed flange relative to the inwardly recessed flange. An air outlet gap is formed between the outwardly recessed flange and the inwardly recessed flange. The inner side wall has a Coanda surface connected to the inwardly recessed flange. The Coanda surface is located below the air outlet gap and is used to guide the compressed air injected from the air outlet gap to flow to the high-temperature components of the engine.

[0013] As a preferred embodiment, the air cooling pipe is strip-shaped, arc-shaped, or ring-shaped.

[0014] This application also provides a control method for an engine cooling system, characterized by comprising the following steps: S1. The temperature sensor detects the real-time temperature T of the engine and feeds it back to the electronic control unit. S2. When the real-time temperature T is greater than or equal to the first threshold T1 and less than the second threshold T2, the electronic control unit increases the gas flow rate of the input air cooling device by controlling the flow control valve, and at the same time controls the main cooling fan to run at low speed. S3. When the cooling capacity of the air cooling device reaches the preset upper limit and the real-time temperature T is greater than or equal to the second threshold T2, the electronic control unit controls the main cooling fan to run at high speed.

[0015] Furthermore, the first threshold T1 is 440℃~460℃, and the second threshold T2 is 540℃~560℃.

[0016] Furthermore, the conditions under which the cooling capacity of the air cooling device reaches the preset upper limit are: the flow control valve is fully open or the outlet pressure of the auxiliary compressor is lower than the minimum effective pressure, which is 0.15 MPa.

[0017] Furthermore, when the exhaust gas discharged from the exhaust manifold is insufficient to drive the turbine to generate compressed air by the auxiliary compressor, the electronic control unit controls the flow control valve to close and controls the main cooling fan to run.

[0018] The beneficial effects of this application are as follows: 1. This application provides an air cooling device on the high-temperature components of the engine. Compressed air from the auxiliary compressor is injected through the air outlet gap, and the ambient air around the air cooling device is entrained by the Coanda effect and fluid viscosity to form a mixed airflow that blows onto the high-temperature components of the engine, thereby achieving air cooling of the high-temperature components of the engine. The air cooling device utilizes the aerodynamic amplification effect, and can entrain a large amount of ambient air with a small amount of compressed air to perform air cooling of the high-temperature parts of the engine, resulting in low energy consumption and good effect.

[0019] 2. This application sets up a secondary compressor, which drives a turbine through the exhaust gas discharged from the engine exhaust manifold, thereby driving the secondary compressor to work and generate compressed air. This compressed air is cooled by an air cooling device to cool the high-temperature components of the engine, effectively recovering and utilizing exhaust gas, reducing the load on the main cooling fan, reducing the power consumption of engine accessories, and improving the engine's fuel economy.

[0020] 3. This application incorporates an electronic control unit, a flow control valve, and a fan clutch. By detecting the real-time engine temperature, the flow control valve and fan clutch are adjusted in stages. When the real-time engine temperature exceeds a first threshold, the air flow to the air cooling system is increased preferentially, while the main cooling fan operates at low speed. When the air cooling capacity reaches its upper limit and the real-time engine temperature exceeds a second threshold, the main cooling fan operates at high speed. This significantly reduces fan power consumption and noise generated during high-speed fan operation.

[0021] 4. This application incorporates an air storage tank and a pressure regulating valve. The compressed air generated by the auxiliary compressor first enters the air storage tank, and then passes through the pressure regulating valve to supply the air cooling device with a constant gas pressure. The pressure regulating valve is used to provide compressed air at a constant pressure to the air cooling device.

[0022] 5. Even if the exhaust gas-driven auxiliary compressor fails, the main cooling fan can still work independently without affecting engine safety. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the present invention.

[0024] Figure 2 This is a schematic diagram of the air cooling device in this invention.

[0025] Figure 3 This is a cross-sectional view of the air cooling device in this invention.

[0026] Illustration labels: 1. Turbine, 2. Main compressor, 3. Auxiliary compressor, 4. Air cooling system, 41. Air cooling pipe, 411. Outer wall, 412. Inner wall, 42. Cooling intake pipe, 43. Exhaust slit, 44. Air supply chamber, 45. Inner flange, 46. Outer flange, 47. Coanda surface, 5. Exhaust manifold, 6. Intercooler, 7. Air tank, 8. Intake manifold, 9. Flow control valve, 10. High-temperature engine components, 11. Electronic control unit, 12. Temperature sensor, 13. Fan clutch, 14. Main cooling fan, 15. Engine. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that, in the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or 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 a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] Please see Figure 1-3This invention provides an engine cooling system, including an engine 15. The engine 15 has an exhaust manifold 5, a turbine 1, an intercooler 6, a main compressor 2, an intake manifold 8, a fan clutch 13, and a main cooling fan 14 connected to the fan clutch 13. The exhaust manifold 5 is connected to the turbine 1, the main compressor 2 is coaxially connected to the turbine 1, and the main compressor 2 is connected to the intercooler 6. The intercooler 6 is used to cool the compressed air from the main compressor 2 before inputting it into the intake manifold 8. The system also includes an electronic control unit 11, an auxiliary compressor 3 coaxially connected to the turbine 1, and a communication circuit. An air cooling device 4 is connected to the auxiliary compressor 3 via a cooling pipe. The air cooling device 4 is installed on the high-temperature component 10 of the engine. A flow control valve 9 is provided on the cooling pipe. The auxiliary compressor 3 is used to input compressed air into the air cooling device 4. The air cooling device 4 is used to perform air cooling on the high-temperature component 10 of the engine to achieve heat dissipation for the engine 15. A temperature sensor 12 is provided on the engine 15 to detect the temperature of the engine 15. The electronic control unit 11 is electrically connected to the fan clutch 13, the temperature sensor 12 and the flow control valve 9 respectively.

[0029] The turbine 1 is driven by exhaust gas from the exhaust manifold 5. The engine 15 is also equipped with an exhaust pipe connected to the exhaust manifold 5 and an intake pipe connected to the intake manifold 8. The exhaust pipe is connected to the turbine 1, and the intake pipe is connected to the intercooler 6. The main compressor 2 and the auxiliary compressor 3 are both centrifugal compressors. The high-temperature components 10 of the engine include at least one of the following: cylinder head, exhaust manifold 5, turbine housing, and EGR cooler housing.

[0030] Temperature sensor 12 is mounted on the exhaust manifold 5 or the turbine housing, and is a type K thermocouple. The main cooling fan 14 is an electronically controlled silicone oil clutch fan, an electronically controlled electromagnetic clutch fan, or an electric fan. The electronic control unit 11 controls the speed of the main cooling fan 14 via the fan clutch 13. The flow control valve 9 is an electronically controlled proportional valve. It should be noted that any parts not detailed in this application are prior art.

[0031] It also includes an air storage tank 7, and the cooling pipeline includes a first sub-pipeline and a second sub-pipeline. The auxiliary compressor 3 is connected to the air inlet of the air storage tank 7 through the first sub-pipeline, and the air cooling device 4 is connected to the air outlet of the air storage tank 7 through the second sub-pipeline. A pressure regulating valve is provided at the air outlet of the air storage tank 7 to provide compressed air at a constant pressure to the air cooling device 4. A flow control valve 9 is located on the second sub-pipeline. In this embodiment, air cooling devices 4 are respectively provided on the exhaust manifold 5 and the turbine housing, and each air cooling device 4 is connected to the air storage tank 7 through the second sub-pipeline. The air storage tank 7 is used to store excess compressed air generated by the auxiliary compressor 3 when the engine 15 is under low load and release it under high load to enhance cooling.

[0032] Specifically, the air cooling device 4 includes an air cooling pipe 41 and a cooling intake pipe 42 connected to the air cooling pipe 41. The cooling intake pipe 42 is connected to a second sub-pipe. The air cooling pipe 41 is provided with an air outlet slit 43. Compressed air from the auxiliary compressor 3 is injected through the air outlet slit 43 of the air cooling pipe 41. After the air is mixed with ambient air around the air cooling pipe 41, it is blown towards the high-temperature components 10 of the engine to achieve air cooling of the high-temperature components 10 of the engine. The air cooling pipe 41 is fixed to the turbine housing by three stainless steel clamps. A high-temperature resistant ceramic fiber gasket is placed between the clamps and the turbine housing to isolate vibration and heat conduction. The high-temperature resistant ceramic fiber gasket is 2mm thick.

[0033] In this embodiment, the air cooling pipe 41 is annular and has an outer side wall 411 and an inner side wall 412. An air supply cavity 44 is formed between the outer side wall 411 and the inner side wall 412. An air outlet gap 43 communicates with the air supply cavity 44. The inner side wall 412 has an inner flange 45 that is recessed into the air supply cavity 44. The outer side wall 411 has an outer flange 46 that faces outward relative to the inner flange 45. An air outlet gap 43 is formed between the outer flange 46 and the inner flange 45. The inner side wall 412 has a Coanda surface 47 that is connected to the inner flange 45. The Coanda surface 47 is located below the air outlet gap 43 and is used to guide the compressed air injected from the air outlet gap 43 to flow to the high-temperature component 10 of the engine. The outer sidewall 411 is made of cast aluminum ZL104 with anodized surface treatment. The inner sidewall 412 is made of stainless steel SUS304 by stamping and the inner surface is polished to Ra0.8μm. The vent gap 43 is machined by precision wire cutting with a width of 0.15-3mm. The outer flange 46 and inner flange 45 are inlaid with wear-resistant tungsten carbide coating on the surface corresponding to the vent gap 43. The thickness of the wear-resistant tungsten carbide coating is 0.1mm, which improves wear resistance and extends service life.

[0034] The exhaust slit 43 is a continuous annular slit. Compressed air from the auxiliary compressor 3 enters the air supply chamber 44 and is then ejected at high speed from the exhaust slit 43. The high-speed airflow flows close to the Coanda surface 47, forming a low-pressure zone in the slit outlet area. It entrains a large amount of surrounding air and mixes it with the jet airflow, which then rushes out from the outlet end of the Coanda surface 47 at a total flow rate of more than 15 times, directly blowing onto the outer surface of the high-temperature engine component 10 to achieve forced air cooling.

[0035] Because the exhaust slit 43 is narrow, compressed air is ejected at high speed. Utilizing the viscosity of the fluid and the Coanda effect, it pulls in air dozens of times its volume, forming a powerful cooling airflow. This airflow acts directly on the surface of the engine's high-temperature components 10, dissipating heat through forced convection, thereby significantly improving the engine 15's thermal management capability without increasing additional energy consumption.

[0036] Of course, the present invention is not limited to the embodiments described above. Several other embodiments based on the design concept of the present invention are also provided below.

[0037] For example, in other embodiments, unlike the embodiments described above, the air cooling pipe 41 is strip-shaped or arc-shaped.

[0038] This application also provides a control method for an engine cooling system, characterized by comprising the following steps: S1. Temperature sensor 12 detects the real-time temperature T of engine 15 and feeds it back to electronic control unit 11.

[0039] S2. When the real-time temperature T is greater than or equal to the first threshold T1 and less than the second threshold T2, the electronic control unit 11 increases the gas flow rate of the input air cooling device 4 by controlling the flow control valve 9, and at the same time controls the main cooling fan 14 to run at low speed.

[0040] S3. When the cooling capacity of the air cooling device 4 reaches the preset upper limit and the real-time temperature T is greater than or equal to the second threshold T2, the electronic control unit 11 controls the main cooling fan 14 to run at high speed.

[0041] The first threshold T1 is 440℃~460℃, and the second threshold T2 is 540℃~560℃. The cooling capacity of the air cooling device 4 reaches the preset upper limit under the following conditions: the real-time temperature T continues to rise, and the flow control valve 9 is fully open or the outlet pressure of the auxiliary compressor 3 is lower than the minimum effective pressure, which is 0.15MPa. A pressure sensor is provided at the outlet of the auxiliary compressor 3, and the electronic control unit 11 is electrically connected to the pressure sensor. In this embodiment, the main cooling fan 14 is an electronically controlled silicone oil clutch fan with a maximum speed of 3200rpm. The low speed of the main cooling fan 14 in this invention is as follows: when the engine speed is lower than 2000rpm, the speed of the main cooling fan 14 is locked at 800±50rpm; when the engine speed is ≥2000rpm, the fan speed is adjusted according to formula n. 风扇转速 = 0.4 × n 发动机转速 The calculation is limited to a maximum of 1500 rpm.

[0042] When the engine 15 is idling or at low speed and low load, and the exhaust gas discharged from the exhaust manifold 5 is insufficient to drive the turbine 1 to drive the auxiliary compressor 3 to generate compressed air, the electronic control unit 11 controls the flow control valve 9 to close and controls the main cooling fan 14 to operate. When the auxiliary compressor 3 malfunctions and cannot work, the electronic control unit 11 controls the flow control valve 9 to close and controls the main cooling fan 14 to operate.

[0043] When the real-time temperature T drops below the first threshold T1, the electronic control unit 11 gradually reduces the opening of the flow control valve 9 and restores the main cooling fan 14 to a low speed. While keeping the flow control valve 9 fully open, the electronic control unit 11 gradually increases the speed of the main cooling fan 14 until the real-time temperature T drops to a safe range.

[0044] This invention is applicable to various types of diesel and gasoline engines used in machinery, and is especially suitable for turbocharged engines with high heat loads that require compact and efficient cooling systems, and has broad application prospects.

[0045] It should be noted that the above embodiments are only used to illustrate the present invention, but the present invention is not limited to the above embodiments. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. An engine cooling system comprising an engine (15), the engine (15) having an exhaust manifold (5), a turbine (1), an intercooler (6), a main compressor (2), an intake manifold (8), a fan clutch (13), and a main cooling fan (14) connected to the fan clutch (13), the exhaust manifold (5) being connected to the turbine (1), the main compressor (2) being coaxially connected to the turbine (1), the main compressor (2) being connected to the intercooler (6), the intercooler (6) being used to cool the compressed air from the main compressor (2) before inputting it into the intake manifold (8), characterized in that, It also includes an electronic control unit (11), an auxiliary compressor (3) coaxially connected to the turbine (1), and an air cooling device (4) connected to the auxiliary compressor (3) through a cooling pipe. The air cooling device (4) is installed on the high-temperature components (10) of the engine. A flow control valve (9) is provided on the cooling pipe. The auxiliary compressor (3) is used to input compressed air into the air cooling device (4). The air cooling device (4) is used to perform air cooling on the high-temperature components (10) of the engine to achieve heat dissipation of the engine (15). The engine (15) is equipped with a temperature sensor (12) for detecting the temperature of the engine (15), and the electronic control unit (11) is electrically connected to the fan clutch (13), the temperature sensor (12) and the flow control valve (9).

2. The engine cooling system according to claim 1, characterized in that, The engine (15) is also provided with an exhaust pipe connected to the exhaust manifold (5) and an intake pipe connected to the intake manifold (8). The exhaust pipe is connected to the turbine (1), and the intake pipe is connected to the intercooler (6). The main compressor (2) and the auxiliary compressor (3) are both centrifugal compressors.

3. The engine cooling system according to claim 2, characterized in that, The engine high-temperature components (10) include at least one of the following: cylinder head, exhaust manifold (5), turbine housing, and EGR cooler housing.

4. The engine cooling system according to claim 1, characterized in that, The temperature sensor (12) is located on the exhaust manifold (5) or the turbine housing.

5. An engine cooling system according to claim 4, characterized in that, The main cooling fan (14) is an electrically controlled silicone oil clutch fan, an electrically controlled electromagnetic clutch fan, or an electronic fan. The electronic control unit (11) controls the speed of the main cooling fan (14) through the fan clutch (13).

6. An engine cooling system according to claim 1, characterized in that, It also includes an air storage tank (7), and the cooling pipeline includes a first sub-pipeline and a second sub-pipeline. The auxiliary compressor (3) is connected to the air inlet of the air storage tank (7) through the first sub-pipeline. The air cooling device (4) is connected to the air outlet of the air storage tank (7) through the second sub-pipeline. A pressure regulating valve is provided at the air outlet of the air storage tank (7). The pressure regulating valve is used to provide compressed air with a constant pressure to the air cooling device (4). The flow control valve (9) is set on the second sub-pipeline.

7. An engine cooling system according to claim 6, characterized in that, The air cooling device (4) includes an air cooling pipe (41) and a cooling intake pipe (42) connected to the air cooling pipe (41). The cooling intake pipe (42) is connected to the second sub-pipe. An air outlet gap (43) is provided on the air cooling pipe (41). Compressed air from the auxiliary compressor (3) is injected through the air outlet gap (43) of the air cooling pipe (41). After the air cooling pipe (41) is entrained and the ambient air around it is mixed, the air is blown toward the high-temperature components (10) of the engine to achieve air cooling of the high-temperature components (10).

8. An engine cooling system according to claim 7, characterized in that, The air cooling pipe (41) has an outer side wall (411) and an inner side wall (412), and an air supply cavity (44) is formed between the outer side wall (411) and the inner side wall (412). An air outlet gap (43) is connected to the air supply cavity (44). The inner side wall (412) has an inner flange (45) that is recessed into the air supply cavity (44). The outer side wall (411) has an outer flange (46) that is outward relative to the inner flange (45). An air outlet gap (43) is formed between the outer flange (46) and the inner flange (45). The inner side wall (412) has a Coanda surface (47) that is connected to the inner flange (45). The Coanda surface (47) is located below the air outlet gap (43) and is used to guide the compressed air injected from the air outlet gap (43) to the high-temperature components (10) of the engine.

9. An engine cooling system according to claim 8, characterized in that, The air cooling pipe (41) is strip-shaped, arc-shaped, or ring-shaped.

10. A control method for an engine cooling system according to any one of claims 1-9, characterized in that, Includes the following steps: S1. Temperature sensor (12) detects the real-time temperature T of engine (15) and feeds it back to electronic control unit (11). S2. When the real-time temperature T is greater than or equal to the first threshold T1 and less than the second threshold T2, the electronic control unit (11) increases the gas flow of the input air cooling device (4) by controlling the flow control valve (9) and at the same time controls the main cooling fan (14) to run at low speed. S3. When the cooling capacity of the air cooling device (4) reaches the preset upper limit and the real-time temperature T is greater than or equal to the second threshold T2, the electronic control unit (11) controls the main cooling fan (14) to run at high speed.

11. The control method for an engine cooling system according to claim 10, characterized in that, The first threshold T1 is 440℃~460℃, and the second threshold T2 is 540℃~560℃.

12. The control method for an engine cooling system according to claim 10, characterized in that, The conditions under which the cooling capacity of the air cooling device (4) reaches the preset upper limit are: the flow control valve (9) is in the fully open state or the outlet pressure of the auxiliary compressor (3) is lower than the minimum effective pressure, which is 0.15MPa.

13. The control method for an engine cooling system according to claim 10, characterized in that, When the exhaust gas discharged from the exhaust manifold (5) is insufficient to drive the turbine (1) to drive the auxiliary compressor (3) to generate compressed air, the electronic control unit (11) controls the flow control valve (9) to close and controls the main cooling fan (14) to run.

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