Method for measuring pressure and flow rate of cooling water circuit of vehicle engine

Abstract

The present invention discloses a method for measuring the pressure and flow rate of a vehicle engine cooling water circuit, and the method comprises the following steps: step S1: drawing a cooling system schematic diagram; step S2: arranging cooling system flow measurement points; step S3: test method. The present invention can realize the optimal design of the coolant flow resistance of the cooling system, and can obtain the resistance of key components such as water pump, cylinder water jacket, cylinder head water jacket, water circuit, and radiator through accurate pressure measurement data, and can improve the key components of the cooling system so that each part reaches the optimal state, and realizes the "low resistance" flow of the entire cooling system; it can realize the reasonable adjustment of the temperature setting point, and use a multi-way control valve to optimize the coolant flow distribution at each engine operating point, and fully adapt to the cooling needs of the engine during actual operation, so as to realize the reasonable control of the engine water temperature in all operating conditions, extend the service life of the engine, and improve the working efficiency of the engine.

Description

Technical Field

[0001] The invention belongs to the technical field of engine testing, and relates to a method for testing the pressure and flow rate of a cooling water circuit of a vehicle engine. Background Art

[0002] With the continuous advancement of automobile technology, the specific power and thermal efficiency of automotive engines have been greatly improved. The cooling water temperature, flow rate, speed, and water flow distribution in the engine cooling system will directly affect the reliability, heat distribution and energy utilization of the engine. The performance of the cooling system directly affects the overall performance of the power system and has become one of the key issues restricting the further development of the engine. Therefore, designing appropriate cooling water flow, pressure, and reasonable flow field distribution has become an indispensable and important link in the research and development of high-efficiency and high-strength engines.

[0003] In the past, the maximum flow value obtained from the water pump bench test was always used in the calculation of the cooling system. However, the resistance of the actual vehicle cooling system is often greater than the resistance of the bench system, resulting in a certain error between the design value and the actual vehicle system. This problem has always plagued the technicians in the vehicle cooling system design. Researching and solving this problem is of great significance to the design of the vehicle cooling system. Summary of the invention

[0004] To achieve the above-mentioned purpose, the present invention provides a method for measuring the pressure and flow rate of a vehicle engine cooling water circuit, which can better obtain the accurate pressure and flow rate of a cooling system of an actual vehicle.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] A method for measuring pressure and flow rate of a vehicle engine cooling water circuit comprises the following steps:

[0007] Step S1: drawing a cooling system schematic diagram;

[0008] Step S11: completing the construction of the main components of the engine cooling system and the confirmation of the cooling system circulation mode;

[0009] Step S12: completing the confirmation of the parameters of the main components of the engine cooling system;

[0010] Step S13: creating an engine cooling system diagram according to the physical connection mode of the main components of the engine cooling system in step S11 and step S12;

[0011] Step S14: drawing a schematic diagram of the engine cooling system according to the different routes and flow rates to the radiator controlled by the thermostat;

[0012] Step S2: Arrange the cooling system pressure and flow measurement points

[0013] Step S21: combining the cooling system circulation mode and the cooling system parts utilization rate in step S14, selecting the maximum range (large cycle) to arrange the measuring points;

[0014] Step S22: Selecting the measuring point location. Since there are resistances in the pipeline, water jacket and radiator of the vehicle engine cooling system, it is necessary to arrange pressure and flow measuring points before and after the water pump, cylinder block, cylinder head, thermostat and radiator, the main parts of the engine cooling system confirmed in step S11;

[0015] Step S3: Test method

[0016] Step S31: Select a suitable flow sensor according to the cooling system component parameters in step S12;

[0017] Step S32: Selecting a characteristic point within the engine speed range of 1000-6000 rpm for testing;

[0018] Step S33: using the crankshaft pulley speed as a reference, using a bevel gauge to measure the engine speed;

[0019] Step S34: According to the working conditions selected in step S32, the coolant flow rate and pressure data under each test condition are measured.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. It can realize the optimal design of the coolant flow resistance of the cooling system. Through accurate pressure measurement data, the resistance of key components such as water pump, cylinder water jacket, cylinder head water jacket, water channel and radiator can be obtained. The key components of the cooling system can be improved to make each part reach the optimal state and realize the "low resistance" flow of the entire cooling system;

[0022] 2. Ability to achieve precise layout of medium flow, use minimum cooling to achieve the most correct temperature distribution, so that each part of the engine can operate at the optimal temperature set point;

[0023] 3. It can realize reasonable adjustment of temperature set point, use multi-way control valve to optimize coolant flow distribution at each engine operating point, fully adapt to the cooling needs of the engine during actual operation, so as to realize reasonable control of engine water temperature in all operating conditions, extend engine service life and improve engine working efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is the pressure-flow characteristic curve;

[0025] Figure 2 This is the structural diagram of the high temperature cooling system;

[0026] Figure 3 This is the structural diagram of the low temperature cooling system;

[0027] Figure 4 It is the high temperature cooling system small cycle mode (coolant temperature <50℃);

[0028] Figure 5 It is a high temperature cooling system small cycle mode (50℃≤coolant temperature<100℃);

[0029] Figure 6 It is a high temperature cooling system small cycle (100℃≤coolant temperature<103℃) mode;

[0030] Figure 7 It is the high temperature cooling system large cycle (103℃≤coolant temperature) mode;

[0031] Figure 8 It is the layout diagram of the pressure and flow measurement points of the cooling system;

[0032] In the figure: 1-water pump; 2-cylinder block; 3-cylinder head; 4-thermostat housing; 5-wax thermostat; 6-electronic thermostat; 7-oil cooler; 8-HVAC temperature control valve; 9-warm air; 10-radiator; 11-fan; 12-first expansion pot; 13-electronic water pump; 14-water-cooled intercooler; 15-supercharger; 16-second expansion pot; 17-low-temperature radiator; A1-engine water inlet flow; A2-cylinder head water jacket outlet flow ; A3-cylinder water jacket water flow; A4-small circulation water flow; A5-HVAC water flow; A6-engine water flow; A7-cylinder head overflow water flow; A8-radiator overflow water flow; B1-water pump inlet pressure; B2-water pump outlet pressure; B3-cylinder head water jacket outlet pressure; B4-cylinder water jacket outlet pressure; B5-HVAC return water pressure; B6-oil cooler outlet pressure; B7-radiator return water pressure. DETAILED DESCRIPTION

[0033] The technical solution of the present invention is further described below in conjunction with the accompanying drawings, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be included in the protection scope of the present invention.

[0034] The present invention provides a method for measuring pressure and flow of a vehicle engine cooling system, the method comprising the following steps:

[0035] Step S1: Draw the cooling system schematic

[0036] Step S11: Complete the confirmation of the main components of the engine cooling system and the cooling system circulation mode.

[0037] The test case of the present invention is a forced circulation water cooling system. Its working process is: the water pump sucks the coolant from outside the engine and pressurizes it, so that it flows into the engine cylinder water jacket from the front end of the engine through the water inlet pipe. In this way, the coolant absorbs heat from the cylinder wall and the temperature rises; it flows to the cylinder head water jacket, and after being heated again, it flows out from the rear end of the cylinder head and enters the radiator along the water outlet pipe. Through the strong suction of the fan, the air flow passes through the radiator at a high speed from front to back. Finally, the heat of the heated coolant continuously passes through the radiator and is dissipated into the atmosphere during the process of flowing through the radiator. The coolant is cooled, and after the cooled coolant flows to the bottom of the radiator, it is pressed into the cylinder water jacket through the water inlet pipe again under the suction and pressurization of the water pump, and circulates continuously in this way, so that the parts of the engine working under high temperature conditions are continuously cooled.

[0038] Step S12: Complete the confirmation of the parameters of the main components of the engine cooling system, including the water pump, cylinder block, cylinder head, thermostat, water inlet pipe, water outlet pipe, oil cooler and expansion pot, etc., wherein:

[0039] Water pump: speed ratio 1.35, pressure-flow characteristic curve as follows Figure 1 As shown;

[0040] Cylinder: Water jacket volume 600ml, pipeline resistance ≤30kpa;

[0041] Cylinder head: water jacket volume 870ml, pipeline resistance ≤33kpa;

[0042] Thermostat: initial opening temperature 100℃, full opening temperature 110℃;

[0043] Electronic thermostat: initial opening temperature without electricity is 103℃, full opening temperature is 115℃;

[0044] Temperature control valve (HVAC): inner diameter 16mm, initial opening temperature 50℃;

[0045] Water inlet: pipe diameter 30mm;

[0046] Water outlet: pipe diameter 30 mm;

[0047] Small circulation pipeline: pipe diameter 18 mm;

[0048] Oil cooler: pipe diameter φ16 mm, pipe resistance ≤35kpa;

[0049] Coolant expansion tank: pipe diameter 8 mm, maximum pressure of pressure cap ≤145kpa.

[0050] Step S13: Creating an engine cooling system diagram according to the physical connection mode of the main components of the engine cooling system in step S11.

[0051] Figure 2The figure shows the main cooling system of the engine (i.e., high-temperature cooling system), which includes the engine water pump, cylinder water jacket, cylinder head water jacket, thermostat housing, thermostat, oil cooler, heater, radiator (main), expansion pot (main), fan, etc. The coolant flows between the above components and forms a closed pressure stabilization system. The specific structure is as follows:

[0052] The high temperature cooling system is composed of a water pump 1, a cylinder block 2, a cylinder head 3, a wax thermostat 5, an electronic thermostat 6, an oil cooler 7, a HVAC temperature control valve 8, a heater 9, a radiator 10, a fan 11 and a first expansion pot 12;

[0053] The inlet of the water pump 1 is connected to the outlet of the radiator 10, and the outlet of the water pump 1 is connected to the water jacket inlet of the cylinder block 2 and the water jacket inlet of the cylinder head 3 respectively;

[0054] The water jacket outlet of the cylinder body 2 is equipped with a wax thermostat 5, and the water jacket outlet of the cylinder head 3 is connected to an electronic thermostat 6 outside the wax thermostat 5;

[0055] The water jacket outlet of the cylinder head 3 is connected to the warm air 9, and the HVAC temperature control valve 8 is arranged in the warm air water inlet pipe;

[0056] The water jacket outlet of the cylinder head 3 is connected to the water inlet of the oil cooler 7, and the water outlet of the oil cooler 7 is connected to the water inlet of the water pump 1;

[0057] The electronic thermostat 6 is connected to the water inlet of the radiator 10;

[0058] The bottom of the first expansion pot 12 is connected to the water inlet of the water pump 1 , and the cover of the first expansion pot 12 is connected to the exhaust port of the radiator 10 , the exhaust port of the cylinder head 3 and the water outlet and exhaust port of the engine.

[0059] Figure 3 The engine accessory cooling system (i.e. low-temperature cooling system) is shown, which is composed of an electronic water pump, a supercharger, a water-cooled intercooler, a radiator (sub), and an expansion pot (sub). It is independent of the high-temperature cooling system and has a water circulation. The electronic water pump independently controls the coolant flow to cool the compressed air, and the water and air perform heat exchange. At the same time, the cooling circuit can also cool the supercharger to protect the intermediate bearing to operate normally. The specific structure is as follows:

[0060] The low temperature cooling system is composed of an electronic water pump 13, a water-cooled intercooler 14, a supercharger 15, a second expansion pot 16 and a low temperature radiator 17;

[0061] The inlet of the electronic water pump 13 is connected to the outlet of the low-temperature radiator 17 , and the outlet of the electronic water pump 13 is connected to the inlet of the water-cooled intercooler 14 ;

[0062] The outlet of the water-cooled intercooler 14 is connected to the second expansion pot 16;

[0063] The second expansion pot 16 is connected to the exhaust port of the low-temperature radiator 17;

[0064] The cooling water inlet of the supercharger 15 is connected to the water inlet of the water-cooled intercooler 14 , and the cooling water outlet of the supercharger 15 is connected to the water outlet of the water-cooled intercooler 14 .

[0065] Step S14: Usually, there are two circulation routes of the coolant in the water cooling system, one is the large circulation and the other is the small circulation. The two are distinguished by whether the coolant flows through the radiator, and the cooling intensity is also different. The small circulation means that the coolant circulates only inside the engine, while the large circulation means that the coolant circulates between the engine and the radiator. Therefore, it is necessary to draw different engine cooling system schematics according to the different routes and flow rates controlled by the thermostat to the radiator.

[0066] Step S141: Draw a schematic diagram of a small cycle of a high-temperature cooling system (coolant temperature < 50°C), such as Figure 4 As shown. The wax thermostat and the electronic thermostat are in the closed valve state, and the flow path to the radiator is disconnected. The HVAC temperature control valve is in the closed state. Even if the heater is turned on, the coolant in the HVAC pipe will not flow at this time. The cylinder water jacket outlet is also in the closed state at this moment because it has not reached the opening temperature of the wax thermostat. No coolant flows out, and the coolant in the cylinder water jacket heats up rapidly. The cylinder head water jacket coolant flows out normally, flows through the oil cooler to cool the engine oil to a certain extent, and finally flows back to the engine water pump. At this time, the water pump, cylinder head water jacket, and oil cooler form a loop, which ensures the cooling requirements of the cylinder head water jacket and the lubricating oil, and ensures that other systems quickly reach the optimal working state.

[0067] Step S142: Draw a schematic diagram of a small cycle of a high-temperature cooling system (50°C ≤ coolant temperature < 100°C), such as Figure 5 As shown. The wax thermostat and the electronic thermostat are in the closed valve state, and the flow path to the radiator is disconnected. The HVAC temperature control valve is in the open state, the coolant in the HVAC pipe begins to flow, and the oil cooler cools the oil to reduce the oil temperature. The cylinder water jacket outlet is in the closed state, no coolant flows out, and the coolant in the cylinder water jacket heats up rapidly. The cylinder head water jacket coolant flows out normally. At this time, the water pump, cylinder head water jacket, and oil cooler form a loop, which ensures the cooling demand of the cylinder head water jacket and ensures that the lubrication system is in the optimal working state.

[0068] Step S143: Draw a schematic diagram of a small cycle of a high-temperature cooling system (100°C ≤ coolant temperature < 103°C), such as Figure 6As shown. The electronic thermostat is in the closed valve state, and the path to the radiator is disconnected. The HVAC temperature control valve is in the open state, the coolant in the HVAC pipe begins to flow, and the oil cooler cools the oil to reduce the oil temperature. The wax thermostat is in the open valve state, the cylinder water jacket outlet is in the open state, the coolant flows out and merges with the cylinder head water jacket. At this time, the water pump, cylinder head water jacket, and cylinder water jacket form a loop, so that the temperature of the entire loop is maintained at the optimal working state of 100°C. At this time, the cylinder head temperature and cylinder body are at the optimal temperature, and the economy is the best.

[0069] Step S144: Draw a schematic diagram of the high-temperature cooling system large cycle (103°C ≤ coolant temperature), such as Figure 7 As shown. The electronic thermostat is in the open valve state, the path to the radiator is open, and the large circulation mode is turned on. The HVAC temperature control valve is in the open state, the coolant begins to flow in the HVAC pipe, and the oil cooler cools the oil to reduce the oil temperature. The wax thermostat is in the open valve state, the cylinder water jacket outlet is in the open state, the coolant flows out and merges with the cylinder head water jacket. At this time, the water pump, cylinder head water jacket, cylinder water jacket and radiator form a loop, so that the temperature of the entire loop begins to cool down and is adjusted to the optimal state.

[0070] Step S2: Arrange the cooling system pressure and flow measurement points

[0071] Based on the cooling system circulation mode and the utilization rate of cooling system parts, select the maximum range to arrange the measuring points.

[0072] like Figure 8As shown, the A1 measuring point is arranged between the radiator and the water pump connecting pipeline to measure the water inlet flow of the entire cooling water circuit; the A2 measuring point is arranged at the cylinder head water jacket outlet position to measure the cylinder head water jacket outlet flow; the A3 measuring point is arranged at the cylinder body water jacket outlet position to measure the cylinder body water jacket outlet flow; the A4 measuring point is arranged between the thermostat housing and the water pump pipeline to measure the small circulation water circuit flow; the A5 measuring point is arranged between the thermostat housing and the warm air pipeline to measure the coolant flow flowing to the warm air; the A6 measuring point is arranged between the engine water outlet and the radiator water inlet pipeline to measure the engine water outlet flow, the A7 measuring point is arranged between the cylinder head air pipe and the first expansion pot to measure the coolant flow in the air pipe; the A8 measuring point is arranged between the radiator air pipe and the first expansion pot to measure the coolant flow in the air pipe; the A9 measuring point is arranged between the first expansion pot and the water inlet of the water pump to measure the first expansion pot replenishment flow. The B1 measuring point is arranged between the radiator and the water pump connecting pipeline to measure the water pump inlet pressure; the B2 measuring point is arranged between the water pump outlet and the cylinder water inlet to measure the water pump outlet pressure; the B3 measuring point is arranged at the cylinder head water jacket outlet to measure the cylinder head water outlet pressure; the B4 measuring point is arranged at the cylinder water jacket outlet to measure the cylinder water jacket outlet pressure; the B5 measuring point is arranged on the warm air return pipe to measure the warm air return pipe pressure; the B6 measuring point is arranged behind the oil cooler to measure the pressure behind the oil cooler; the B7 measuring point is arranged between the engine water outlet and the radiator to measure the engine water outlet pressure.

[0073] Step S3: Test method

[0074] Step S31: Select a suitable flow sensor according to the cooling system component parameters of step S12. The present invention adopts electromagnetic flowmeters produced by Tokyo Metering, A1~A6 select electromagnetic flowmeters with a range of 250L / min, and A7 and A8 select electromagnetic flowmeters with a range of 55L / min.

[0075] Step S32: Select an external characteristic point in the engine speed range of 1000-6000 rpm for testing.

[0076] Step S33: Using the crankshaft pulley speed as a reference, the engine speed is measured using a bevel gauge.

[0077] Step S34: Measure the coolant flow rate and pressure under each test condition of step S141, step S142, step S143, and step S144, and fill in the test measurement table, as shown in Table 1 and Table 2.

[0078] Table 1

[0079]

[0080] Table 2

[0081]

Claims

1. A method for measuring pressure and flow rate of a vehicle engine cooling water circuit, characterized in that: The method comprises the following steps: Step S1: Draw a cooling system schematic diagram. The specific steps are as follows: Step S11: completing the component composition of the engine cooling system and the confirmation of the cooling system circulation mode; Step S12: completing the confirmation of engine cooling system component parameters; Step S13: creating an engine cooling system diagram according to the physical connection mode of the engine cooling system components in step S11 and step S12; Step S14: drawing a schematic diagram of the engine cooling system according to the different routes and flow rates to the radiator controlled by the thermostat; The engine cooling system includes a high-temperature cooling system and a low-temperature cooling system, wherein: The high temperature cooling system includes a water pump, a cylinder block, a cylinder head, a wax thermostat, an electronic thermostat, an oil cooler, a HVAC temperature control valve, a heater, a radiator and a first expansion pot; The inlet of the water pump is connected to the outlet of the radiator, and the outlet of the water pump is connected to the water jacket inlet of the cylinder body and the water jacket inlet of the cylinder head respectively; The water jacket outlet of the cylinder body is equipped with a wax thermostat, and the water jacket outlet of the cylinder head is connected to an electronic thermostat outside the wax thermostat; The water jacket outlet of the cylinder head is connected to the warm air water inlet pipe, and the HVAC temperature control valve is arranged in the warm air water inlet pipe; The water jacket outlet of the cylinder head is connected to the water inlet of the oil cooler, and the water outlet of the oil cooler is connected to the water inlet of the water pump; The thermostat is connected to the water inlet of the radiator; The bottom of the first expansion pot is connected to the water inlet of the water pump, and the cover of the first expansion pot is connected to the exhaust port of the radiator, the exhaust port of the cylinder head and the water outlet and exhaust port of the engine; The low-temperature cooling system includes an electronic water pump, a water-cooled intercooler, a supercharger, a second expansion pot and a low-temperature radiator; The inlet of the electronic water pump is connected to the outlet of the low-temperature radiator, and the outlet of the electronic water pump is connected to the inlet of the water-cooled intercooler; The outlet of the water-cooled intercooler is connected to the second expansion pot; The second expansion pot is connected to the exhaust port of the low-temperature radiator; The cooling water inlet of the supercharger is connected to the water inlet of the water-cooled intercooler, and the cooling water outlet of the supercharger is connected to the water outlet of the water-cooled intercooler; The cooling system schematic diagram includes the following three small cycle schematic diagrams and one large cycle schematic diagram: Schematic diagram of small circulation of high-temperature cooling system: When the coolant temperature is less than 50℃, the wax thermostat and the electronic thermostat are in the closed valve state, and the flow path to the radiator is disconnected; the HVAC temperature control valve is in the closed state, and the coolant does not flow in the HVAC pipe; the water outlet of the cylinder water jacket is in the closed state, and no coolant flows out, and the coolant in the cylinder water jacket heats up rapidly; the coolant in the cylinder head water jacket flows out normally, flows through the oil cooler to cool the engine oil, and finally flows back to the engine water pump; at this time, the water pump, cylinder head water jacket, and oil cooler form a loop; Schematic diagram of small cycle of high-temperature cooling system: 50℃≤coolant temperature<100℃, wax thermostat and electronic thermostat are in closed valve state, and the flow path to the radiator is disconnected; HVAC temperature control valve is in open state, coolant starts to flow in the HVAC pipe, and the oil cooler cools the oil to reduce the oil temperature; the cylinder water jacket outlet is in closed state, no coolant flows out, and the coolant in the cylinder water jacket heats up rapidly; the cylinder head water jacket coolant flows out normally; at this time, the water pump, cylinder head water jacket, and oil cooler form a loop; Schematic diagram of small cycle of high-temperature cooling system: 100℃≤coolant temperature<103℃, the electronic thermostat is in the closed valve state, and the path to the radiator is disconnected; the HVAC temperature control valve is in the open state, the coolant in the HVAC pipe begins to flow, and the oil cooler cools the oil to reduce the oil temperature; the wax thermostat is in the open valve state, the cylinder water jacket outlet is in the open state, the coolant flows out and merges with the cylinder head water jacket, at this time the water pump, cylinder head water jacket, and cylinder water jacket form a loop; Schematic diagram of the large circulation of the high-temperature cooling system: 103℃≤coolant temperature, the electronic thermostat is in the open valve state, the flow path to the radiator is open, and the large circulation mode is turned on; the HVAC temperature control valve is in the open state, the coolant in the HVAC pipe begins to flow, and the oil cooler cools the oil to reduce the oil temperature; the wax thermostat is in the open valve state, the cylinder water jacket outlet is in the open state, the coolant flows out and merges with the cylinder head water jacket. At this time, the water pump, cylinder head water jacket, cylinder water jacket and radiator form a loop. Step S2: Arrange the cooling system pressure and flow measurement points Combined with the cooling system circulation mode and the cooling system parts utilization rate, the maximum range of measurement points is selected. The specific arrangement positions of the measurement points are as follows: The A1 measuring point is arranged between the radiator and the water pump connecting pipeline to measure the water inlet flow of the entire cooling water circuit; the A2 measuring point is arranged at the outlet of the cylinder head water jacket to measure the outlet flow of the cylinder head water jacket; the A3 measuring point is arranged at the outlet of the cylinder water jacket to measure the outlet flow of the cylinder water jacket; the A4 measuring point is arranged between the thermostat housing and the water pump pipeline to measure the flow of the small circulation water circuit; the A5 measuring point is arranged between the thermostat housing and the warm air pipeline to measure the coolant flow to the warm air; the A6 measuring point is arranged between the engine water outlet and the radiator water inlet pipeline to measure the engine water outlet flow; the A7 measuring point is arranged between the cylinder head air pipe and the first expansion pot to measure the coolant flow in the air pipe; the A8 measuring point is arranged between the radiator air pipe and the first The A9 measuring point is arranged between the first expansion pot and the water inlet of the water pump to measure the replenishment flow of the first expansion pot; the B1 measuring point is arranged between the radiator and the water pump connecting pipeline to measure the water pump inlet pressure; the B2 measuring point is arranged between the water pump outlet and the cylinder upper water inlet to measure the water pump outlet pressure; the B3 measuring point is arranged at the cylinder head water jacket outlet to measure the cylinder head water outlet pressure; the B4 measuring point is arranged at the cylinder water jacket outlet to measure the cylinder water jacket outlet pressure; the B5 measuring point is arranged on the warm air return pipe to measure the warm air return pipe pressure; the B6 measuring point is arranged behind the oil cooler to measure the pressure behind the oil cooler; the B7 measuring point is arranged between the engine water outlet and the radiator to measure the engine water outlet pressure; Step S3: Test method Step S31: Selecting a suitable flow sensor according to the parameters of cooling system components; Step S32: Selecting a characteristic point within the engine speed range of 1000-6000 rpm for testing; Step S33: using the crankshaft pulley speed as a reference, using a bevel gauge to measure the engine speed; Step S34: According to the working conditions selected in step S32, the coolant flow rate and pressure data under each test condition are measured.

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