Engine plateau cold start test system and test method

Abstract

The present invention provides an engine plateau cold start test system and test method, which relates to the field of engine test technology, wherein the test system includes: a low temperature environment chamber; an oil supply unit, the oil supply unit includes an oil storage tank and a fuel consumption meter; the oil storage tank is placed in the low temperature environment chamber, the fuel consumption meter is placed outside the low temperature environment chamber and is connected with an oil inlet pipeline and an oil return pipeline, the oil inlet pipeline is connected with the oil storage tank, and the oil return pipeline is used to connect the engine to be tested; an oil temperature reduction heat exchanger and an oil temperature increase heat exchanger are respectively provided on the oil inlet pipeline and the oil return pipeline; an air supply unit, the air supply unit includes an air guide passage placed outside the low temperature environment chamber, an air intake fan, a negative pressure regulating valve, a positive pressure regulating valve and an exhaust fan are sequentially arranged on the air guide passage, and the air guide passage is connected with an air intake passage and an exhaust passage between the negative pressure regulating valve and the positive pressure regulating valve. The test system provided by the present invention can meet the plateau low temperature cold start test with different ambient temperatures and different altitudes.

Description

Technical Field

[0001] The present invention generally relates to the technical field of engine testing, and in particular to an engine plateau cold start testing system and a testing method. Background Art

[0002] All kinds of construction machinery, transport vehicles and special equipment will encounter problems such as difficulty in cold start, unstable idling and large amounts of black smoke when facing high altitude cold conditions. Therefore, it is very important to verify the cold start performance of an engine in high altitude.

[0003] When conducting engine plateau cold start R&D tests, most engine manufacturers and vehicle manufacturers will use engine plateau field tests, which may lead to a long test cycle, affect the product development progress and market launch time, and invest a lot of manpower and material resources. To solve this problem, the current test is carried out by building an environmental chamber that can simulate different temperatures and altitudes, but the existing environmental chamber construction cost and subsequent maintenance cost are high, and this method cannot accurately control the low-temperature cold start oil inlet temperature, intake air temperature and intake air pressure. Summary of the invention

[0004] In view of the above-mentioned defects or deficiencies in the prior art, it is desired to provide an engine plateau cold start test system and test method to solve the above-mentioned problems.

[0005] A first aspect of the present invention provides an engine plateau cold start test system, comprising:

[0006] A low temperature environment chamber, in which the engine to be tested is placed;

[0007] An oil supply unit, the oil supply unit comprising an oil storage tank and an oil consumption meter; the oil storage tank is placed in the low temperature environment chamber and is used to supply oil to the engine to be tested; the oil consumption meter is placed outside the low temperature environment chamber and is connected with an oil inlet pipeline and an oil return pipeline, the oil inlet pipeline is connected with the oil storage tank, and the oil return pipeline is used to connect with the engine to be tested; an oil temperature reduction heat exchanger and an oil temperature increase heat exchanger are respectively provided on the oil inlet pipeline and the oil return pipeline;

[0008] The oil temperature reduction heat exchanger is used to reduce the temperature of the fuel in the oil inlet pipeline to the test temperature before supplying it to the oil storage tank, so as to provide accurate oil inlet temperature for the cold start condition, low temperature steady state and transient condition of the engine to be tested;

[0009] An air supply unit, the air supply unit includes an air guide passage arranged outside the low-temperature environment chamber, the air guide passage is provided with an air intake fan, a negative pressure regulating valve, a positive pressure regulating valve and an exhaust fan in sequence, the air guide passage is connected with an air intake passage and an exhaust passage between the negative pressure regulating valve and the positive pressure regulating valve, the air intake passage is used to connect to the air intake end of the engine to be tested, and the exhaust passage is used to connect to the exhaust end of the engine to be tested.

[0010] According to the technical solution provided by the present invention, the air intake passage comprises an inner passage disposed inside the low temperature environment chamber and an outer passage disposed outside the low temperature environment chamber, and the outer passage is provided with a first node and a second node;

[0011] The air supply unit also includes:

[0012] an air cooler, the air cooler being connected in parallel between the first node and the second node on the external passage, and being used for cooling and regulating the intake air temperature;

[0013] a first control valve, the first control valve being disposed between the first node and the air cooler;

[0014] A second control valve is provided between the first node and the second node.

[0015] According to the technical solution provided by the present invention, a ventilation pipe is provided on the inner passage, the ventilation pipe connects the inner passage and the outside of the low-temperature environment chamber, and a third control valve is provided on the ventilation pipe.

[0016] According to the technical solution provided by the present invention, it also includes a refrigeration unit, which is used to provide a refrigerant; the refrigeration unit is connected to the air cooler through a first circulation pipeline, and the refrigeration unit is connected to the oil temperature reduction heat exchanger through a second circulation pipeline, and the refrigeration unit is used to adjust the temperature of the air cooler and the oil temperature reduction heat exchanger by circulating the refrigerant.

[0017] According to the technical solution provided by the present invention, a fourth control valve is provided on the first circulation pipeline, and the fourth control valve is used to control the flow rate of refrigerant in the first circulation pipeline; a fifth control valve is provided on the second circulation pipeline, and the fifth control valve is used to control the flow rate of refrigerant in the second circulation pipeline.

[0018] According to the technical solution provided by the present invention, the air supply unit also includes an exhaust temperature heat exchanger, and the exhaust temperature heat exchanger is used to cool down and regulate the exhaust temperature.

[0019] According to the technical solution provided by the present invention, the air supply unit also includes a dehumidifier, and the dehumidifier is arranged on the air intake side of the air intake fan.

[0020] According to the technical solution provided by the present invention, the oil supply unit also includes a pressure regulating device, which is connected in series to the oil inlet pipeline and the oil return pipeline to adjust the oil inlet pressure and the oil return pressure.

[0021] A second aspect of the present invention provides an engine plateau cold start test method, based on the engine plateau cold start test system as described above, the method comprises:

[0022] Opening the low temperature environment chamber, and placing the engine to be tested in the low temperature environment chamber for freezing and standing;

[0023] Starting the refrigeration unit and the dehumidifier, setting the refrigeration temperature of the refrigeration unit, closing the second control valve and opening the first control valve, and adjusting the temperatures of the air cooler and the oil temperature reduction heat exchanger respectively through the fourth control valve and the fifth control valve so that the air intake temperature and the oil intake temperature meet the test temperature;

[0024] After the engine to be tested has been left at rest, the intake pressure is adjusted to be greater than the atmospheric pressure at the local altitude, and the third control valve is opened to allow the air in the external passage to exchange heat with the air cooler to drop to the test temperature;

[0025] When the temperature of the air discharged from the ventilation pipe reaches the test temperature, the third control valve is closed, and the intake pressure is adjusted to meet the altitude required to be simulated;

[0026] When the intake pressure meets the altitude required to be simulated, the engine to be tested is started to begin the test.

[0027] According to the technical solution provided by the present invention, while the temperatures of the air cooler and the oil temperature reduction heat exchanger are respectively adjusted by the fourth control valve and the fifth control valve, the invention also includes:

[0028] The temperature of the exhaust temperature heat exchanger is adjusted to reduce the exhaust temperature; and the temperature of the oil temperature increase heat exchanger is adjusted to increase the return oil temperature.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows: by setting up a low-temperature environment chamber, the test temperature can be controlled by placing the engine to be tested in the low-temperature environment chamber for testing; by placing an oil storage tank in the low-temperature environment chamber, the oil storage tank pre-stores fuel for the engine to be tested to run for a period of time, and before the test starts, the fuel in the oil storage tank and the engine to be tested can be frozen and left to stand in the low-temperature environment chamber together, thereby better simulating the cold start state and providing accurate oil inlet temperature for the cold start condition, low-temperature steady state and transient condition of the engine to be tested; by setting up a fuel consumption meter, the fuel flow rate of the oil inlet pipeline and the oil return pipeline can be measured. The fuel consumption of the engine to be tested is calculated. The fuel consumption meter is set outside the low-temperature environment chamber to avoid damage to the fuel consumption meter caused by the low-temperature environment. By respectively setting an oil temperature reduction heat exchanger and an oil temperature increase heat exchanger on the oil inlet pipeline and the oil return pipeline, the fuel supplied to the oil storage tank can be cooled to simulate the low-temperature environment, and the return oil of the engine to be tested can be cooled to prevent the return oil temperature from being too low and affecting the fuel consumption meter; by setting an air supply unit, the intake pressure can be adjusted by utilizing the coordinated action of the intake fan, the negative pressure regulating valve, the positive pressure regulating valve and the exhaust fan, thereby simulating the air pressure environment at different altitudes. The test system provided by the present invention can realize cold start tests of different engines at different altitudes, and has a simple structure and is easy to maintain. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0031] Figure 1 A schematic diagram of the structure of an engine plateau cold start test system provided in Example 1 of the present invention;

[0032] Figure 2 Schematic diagram of the change of oil inlet temperature before and after adding the oil storage tank during the -10℃ engine cold start process;

[0033] Figure 3 Schematic diagram of the change of intake air temperature before and after adding exhaust passage for the -20℃ engine cold start process;

[0034] Figure 4 This is a schematic diagram of the change in oil inlet temperature before and after the oil storage tank is installed during the WHTC test cycle of a -10℃ engine;

[0035] Figure 5 This is a flow chart of the steps of the engine plateau cold start test method provided in Example 2 of the present invention.

[0036] Figure numbers: 1. Low temperature environment chamber; 2. Engine to be tested; 3. Oil storage tank; 4. Oil supply unit; 5. Fuel consumption meter; 6. Oil inlet pipeline; 7. Oil return pipeline; 8. Heat exchanger for lowering oil temperature; 9. Heat exchanger for raising oil temperature; 10. Air supply unit; 11. Air guide passage; 12. Air intake fan; 13. Negative pressure regulating valve; 14. Positive pressure regulating valve; 15. Exhaust fan; 16. Air intake passage; 17. Exhaust passage; 18. Internal passage; 19. External passage 1. First node; 20. Second node; 21. Air cooler; 23. First control valve; 24. Second control valve; 25. Ventilation pipe; 26. Third control valve; 27. Refrigeration unit; 28. First circulation pipeline; 29. ​​Second circulation pipeline; 30. Fourth control valve; 31. Fifth control valve; 32. Exhaust heat exchanger; 33. Dehumidifier; 34. Pressure regulating device; 35. Temperature control system; 36. Observation window; 37. Oil supply equipment. DETAILED DESCRIPTION

[0037] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the relevant invention, rather than to limit the invention. It should also be noted that, for ease of description, only the parts related to the invention are shown in the accompanying drawings.

[0038] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0039] The plateau cold start test of the engine is usually carried out in a low-temperature environmental chamber, which simulates the low-temperature environment of the engine in the plateau. During the initial test, the engine's fuel supply system and air supply system are usually placed in the low-temperature environmental chamber together, and the intake air temperature and oil intake temperature are simulated at low temperatures through the low-temperature environmental chamber. However, placing the fuel supply system and the air supply system in a low-temperature environmental chamber for a long time can easily reduce the accuracy of the equipment or even cause damage. In addition, the existing test system can only adjust the test temperature, and cannot adjust the oil intake pressure and air intake pressure according to the air pressure at different altitudes, which leads to inaccurate test results and the simulated scenarios are relatively single.

[0040] Example 1

[0041] Please refer to Figure 1 This embodiment provides an engine plateau cold start test system, comprising:

[0042] A low temperature environment chamber 1, wherein the low temperature environment chamber 1 is used to place an engine 2 to be tested;

[0043] The oil supply unit 4 includes an oil storage tank 3 and a fuel consumption meter 5; the oil storage tank 3 is arranged in the low temperature environment chamber 1, and is used to supply oil to the engine 2 to be tested; the fuel consumption meter 5 is placed outside the low temperature environment chamber 1 and is connected with an oil inlet pipeline 6 and an oil return pipeline 7, the oil inlet pipeline 6 is connected with the oil storage tank 3, and the oil return pipeline 7 is used to connect with the engine 2 to be tested; the oil inlet pipeline 6 and the oil return pipeline 7 are respectively provided with an oil temperature reducing heat exchanger 8 and an oil temperature increasing heat exchanger 9;

[0044] The oil temperature reduction heat exchanger 8 is used to reduce the temperature of the fuel in the oil inlet pipeline 6 to the test temperature before supplying it to the oil storage tank 3, so as to provide accurate oil inlet temperature for the cold start condition, low temperature steady state and transient condition of the engine 2 to be tested;

[0045] An air supply unit 10 includes an air guide passage 11 disposed outside the low-temperature environment chamber 1, and an air intake fan 12, a negative pressure regulating valve 13, a positive pressure regulating valve 14 and an exhaust fan 15 are sequentially arranged on the air guide passage 11. The air guide passage 11 is connected with an air intake passage 16 and an exhaust passage 17 between the negative pressure regulating valve 13 and the positive pressure regulating valve 14. The air intake passage 16 is used to connect to the air intake end of the engine 2 to be tested, and the exhaust passage 17 is used to connect to the exhaust end of the engine 2 to be tested.

[0046] Specifically, the test system provided in this embodiment includes three parts: a low temperature environment chamber 1, a fuel supply unit 4 and an air supply unit 10. The low temperature environment chamber 1 is used to provide a low temperature environment for testing the engine 2 to be tested; the fuel supply unit 4 is used to provide fuel of different temperatures to the engine 2 to be tested, so as to simulate the intake temperature at different altitudes; the air supply unit 10 is used to provide air of different pressures to the engine 2 to be tested, so as to simulate the intake pressure at different altitudes.

[0047] Specifically, a test space is formed inside the low temperature environment chamber 1. The test space is set according to the displacement of the engine to be tested, and the operating space for the upper and lower racks of the engine is reserved, so that the volume of the low temperature environment chamber 1 does not need to be too large; the low temperature environment chamber 1 is provided with a temperature control system 35, through which the temperature of the test space can be adjusted to simulate the test environment of different temperatures. In the test preparation stage, the engine 2 to be tested is cooled to the test temperature in advance in the test space, and the test temperature is the temperature corresponding to the altitude to be simulated; the low temperature environment chamber 1 is provided with an observation window 36, through which the working state of the engine 2 to be tested can be observed externally, and the observation window 36 is composed of three layers of tempered glass and has a heating function. The oil storage tank 3 stores fuel, and in the test preparation stage, the fuel in the oil storage tank 3 is cooled to the test temperature together with the engine 2 to be tested. The low temperature environment chamber 1 is also provided with a starter and a battery matching the engine 2 to be tested, the starter is used to drag the engine 2 to be tested during cold start, and the battery is used to power the starter.

[0048] Specifically, the oil supply unit 4 includes at least one oil storage tank 3 and a fuel consumption meter 5. The oil storage tank 3 is placed inside the test space and is used to supply fuel to the engine 2 to be tested. The fuel consumption meter 5 is placed outside the low temperature environment chamber 1 to prevent the low temperature inside the low temperature environment chamber 1 from damaging the fuel consumption meter 5. The fuel supply port of the fuel consumption meter 5 is connected to the external oil supply device 37. The oil inlet of the fuel consumption meter 5 is connected to the oil storage tank 3 through the oil inlet pipeline 6. The fuel provided by the external oil supply device 37 is supplied to the oil storage tank 3 through the fuel consumption meter 5 and the oil inlet pipeline 6; the oil return port of the fuel consumption meter 5 is connected to the engine 2 to be tested through the oil return pipeline 7. The fuel consumption meter 5 calculates the fuel consumption of the engine 2 to be tested at low temperature through the fuel flow of the oil inlet and the oil return port. The oil inlet pipeline 6 is provided with an oil temperature reduction heat exchanger 8, which is used to reduce the temperature of the fuel in the oil inlet pipeline 6 to the test temperature before supplying it to the oil storage tank 3, providing accurate oil inlet temperature for the cold start condition, low temperature steady state and transient condition of the engine 2 to be tested, so that the oil inlet temperature can meet the test temperature as much as possible. The oil return pipeline 7 is provided with an oil temperature increase heat exchanger 9, which is used to increase the temperature of the return oil of the engine 2 to be tested, so as to avoid the low temperature fuel affecting the accuracy of the fuel consumption meter 5 detection.

[0049] refer to Figure 2 This embodiment further explains the beneficial effects of the oil storage tank 3 through experimental data, such as Figure 2 As shown, Figure 2 The test data shown is for a test temperature of -10°C. Figure 2 The horizontal axis is the duration of the engine cold start process, and the vertical axis is the starting speed and oil inlet temperature of the engine cold start process. Figure 2 It can be seen that after the oil storage tank 3 is installed, it can ensure that the oil inlet temperature of the entire starting process is maintained within ±1°C of the test temperature, making it more suitable for the actual working environment of the vehicle in the low-temperature cold machine.

[0050] Specifically, the air supply unit 10 includes an air intake fan 12, a negative pressure regulating valve 13, a positive pressure regulating valve 14 and an exhaust fan 15. The air intake fan 12, the negative pressure regulating valve 13, the positive pressure regulating valve 14 and the exhaust fan 15 are arranged outside the low temperature environment chamber 1 and are connected in series through the air guide passage 11. The air intake passage 16 and the exhaust passage 17 are connected in the area between the negative pressure regulating valve 13 and the positive pressure regulating valve 14 of the air guide passage 11. The air intake passage 16 is arranged on a side close to the negative pressure regulating valve 13, and the exhaust passage 17 is arranged on a side close to the positive pressure regulating valve 14. The air intake passage 16 is connected to the air intake end of the engine 2 to be tested, and the exhaust passage 17 is connected to the exhaust end of the engine 2 to be tested.

[0051] When the air supply unit 10 is working, part of the air sucked in by the intake fan 12 enters the engine to be tested 2 through the intake passage 16, and the other part is discharged to the exhaust fan 15 through the air guide passage 11. The air exhausted by the engine to be tested 2 is discharged to the exhaust fan 15 through the exhaust passage 17 when the engine to be tested is working; the intake pressure can be controlled by adjusting the positive pressure regulating valve 14 and the negative pressure regulating valve 13. When the engine to be tested 2 needs to be tested at a low altitude, the air supply unit 10 needs to simulate positive pressure, inhale air into the passage through the intake fan 12, and hold the air pressure in the passage to the required pressure through the positive pressure regulating valve 14, thereby simulating the positive pressure situation at a low altitude; when the engine to be tested 2 needs to be tested at a high altitude, the air supply unit 10 needs to simulate negative pressure, extract the gas in the passage through the exhaust fan 15, and adjust the negative pressure in the passage through the negative pressure regulating valve 13. The air supply unit 10 provided in this embodiment can simulate an altitude of 540 mbar to 1050 mbar, thereby achieving regulation of different intake pressures of the engine 2 to be tested.

[0052] Furthermore, the air inlet passage 16 includes an inner passage 18 disposed inside the low temperature environment chamber 1 and an outer passage 19 disposed outside the low temperature environment chamber 1, and a first node 20 and a second node 21 are provided on the outer passage 19;

[0053] The air supply unit 10 further includes:

[0054] An air cooler 22, the air cooler 22 is connected in parallel between the first node 20 and the second node 21 on the external passage 19, and is used to cool down and regulate the intake air temperature;

[0055] A first control valve 23, wherein the first control valve 23 is disposed between the first node 20 and the air cooler 22;

[0056] The second control valve 24 is disposed between the first node 20 and the second node 21 .

[0057] Specifically, the air intake passage 16 includes two parts, the inner passage 18 and the outer passage 19. The inner passage 18 is a section of the air intake passage 16 placed inside the low-temperature environment chamber 1, and the outer passage 19 is a section of the air intake passage 16 placed outside the low-temperature environment chamber 1. The outer passage 19 has a branch in parallel in the area between the first node 20 and the second node 21. On this basis, the air supply unit 10 also includes an air cooler 22, a first control valve 23 and a second control valve 24. The air cooler 22 is arranged on the branch of the outer passage 19. The air cooler 22 is used to reduce the intake air temperature to different temperatures to meet the requirements of different test environments; the first control valve 23 is used to control the passage between the first node 20 and the air cooler 22, and the second control valve 24 is used to control the passage between the first node 20 and the second node 21. When the first control valve 23 is closed and the second control valve 24 is opened, the air in the intake passage 16 can directly enter the engine 2 to be tested for normal temperature testing; when the second control valve 24 is closed and the first control valve 23 is opened, the air in the intake passage 16 is first cooled by the air cooler 22 before entering the engine 2 to be tested.

[0058] Furthermore, a vent pipe 25 is provided on the inner passage 18 , and the vent pipe 25 connects the inner passage 18 and the outside of the low-temperature environment chamber 1 . A third control valve 26 is provided on the vent pipe 25 .

[0059] Specifically, the inner passage 18 is connected with the vent pipe 25, and the opening and closing of the vent pipe 25 is controlled by the third control valve 26. When the third control valve 26 is opened, the inner passage 18 is connected with the outside of the low temperature environment chamber 1. The functions of the vent pipe 25 and the third control valve 26 are to allow air to circulate, so that the air can better exchange heat with the air cooler 22, so as to solve the problem that the engine 2 to be tested cannot exchange heat with the air in the rear end passage of the air cooler 22 when it is stationary, resulting in a high temperature of the air section that affects the test results. In addition, the setting of the vent pipe 25 can also effectively reduce the temperature fluctuation of the intake temperature, so that the intake temperature can meet the test temperature as much as possible.

[0060] refer to Figure 3 This embodiment further explains the beneficial effects of the vent pipe 25 through experimental data, such as Figure 3 As shown, Figure 3 The test data shown is for a test temperature of -20°C. Figure 2 The horizontal axis is the duration of the engine cold start process, and the vertical axis is the starting speed and intake air temperature of the engine cold start process. Figure 3 It can be seen that after installing the vent pipe 25, it can ensure that the intake air temperature during the entire starting process is maintained within ±1°C of the test temperature, making it more suitable for the actual working environment of the vehicle in the low-temperature cold machine.

[0061] Furthermore, it also includes a refrigeration unit 27, which is used to provide a refrigerant; the refrigeration unit 27 is connected to the air cooler 22 through a first circulation pipeline 28, and the refrigeration unit 27 is connected to the oil temperature reduction heat exchanger 8 through a second circulation pipeline 29, and the refrigeration unit 27 is used to adjust the temperature of the air cooler 22 and the oil temperature reduction heat exchanger 8 through the circulation of the refrigerant.

[0062] Specifically, the test system also includes a refrigeration unit 27, which is provided with a refrigerant. The refrigeration unit 27 provides a refrigerant at -50-30°C through refrigeration, and circulates the refrigerant after pressurizing it with a compressor to achieve cooling; the refrigeration unit 27 realizes the circulation of refrigerant with the air cooler 22 through a first circulation pipeline 28, and the refrigeration unit 27 realizes the circulation of refrigerant with the oil temperature reduction heat exchanger 8 through a second circulation pipeline 29, and the air cooler 22 and the oil temperature reduction heat exchanger 8 achieve cooling through the refrigerant.

[0063] Furthermore, a fourth control valve 30 is provided on the first circulation pipeline 28, and the fourth control valve 30 is used to control the flow rate of refrigerant in the first circulation pipeline 28; a fifth control valve 31 is provided on the second circulation pipeline 29, and the fifth control valve 31 is used to control the flow rate of refrigerant in the second circulation pipeline 29.

[0064] Specifically, the openings of the fourth control valve 30 and the fifth control valve 31 are adjustable through PID control. By controlling the openings of the fourth control valve 30 and the fifth control valve 31, the refrigerant flow rates in the first circulation pipeline 28 and the second circulation pipeline 29 can be adjusted respectively, thereby changing the temperatures of the air cooler 22 and the oil temperature reduction heat exchanger 8.

[0065] Furthermore, the air supply unit 10 also includes an exhaust temperature heat exchanger 32, and the exhaust temperature heat exchanger 32 is used to cool down and regulate the exhaust temperature.

[0066] Specifically, the exhaust temperature heat exchanger 32 is arranged between the positive pressure regulating valve 14 and the exhaust fan 15. The exhaust temperature heat exchanger 32 is temperature-controlled by 7°C circulating water. The exhaust temperature heat exchanger 32 is used to cool down the exhaust temperature of the engine 2 to be tested to prevent the exhaust temperature from being too high and affecting the working state of the exhaust fan 15 or causing damage to the exhaust fan 15.

[0067] Furthermore, the air supply unit 10 further includes a dehumidifier 33 , and the dehumidifier 33 is disposed on the air intake side of the air intake fan 12 .

[0068] Specifically, the dehumidifier 33 may be a honeycomb rotary dehumidifier, and the dehumidifier 33 provides the air supply unit 10 with dry air that does not produce frost under an intake condition of -50°C.

[0069] Furthermore, the oil supply unit 4 further includes a pressure regulating device 34, which is connected in series to the oil inlet pipeline 6 and the oil return pipeline 7, and is used to regulate the oil inlet pressure and the oil return pressure.

[0070] Specifically, the pressure regulating device 34 is disposed outside the low-temperature environment chamber 1 , and the oil inlet pressure and the oil return pressure can be adjusted by the pressure regulating device 34 , thereby simulating the oil pressure of different engines at different altitudes.

[0071] In addition to testing the engine cold start, the present invention also tests the WHTC test cycle conditions, such as Figure 4 As shown, Figure 4 The test data of the WHTC test cycle process is shown when the test temperature is -10℃. Figure 4 The horizontal axis is the duration of the WHTC test cycle, and the vertical axis is the oil inlet temperature of the WHTC test cycle. Figure 4 It can be seen that the setting of the oil storage tank 3 can ensure that the oil inlet temperature meets the test temperature under the WHTC test cycle conditions, and effectively reduce the temperature fluctuation of the oil inlet temperature.

[0072] Example 2

[0073] Please refer to Figure 5 This embodiment provides an engine plateau cold start test method, based on the engine plateau cold start test system as described in Example 1, the method comprises:

[0074] S1: Open the low temperature environment chamber 1, and place the engine 2 to be tested in the low temperature environment chamber 1 for freezing and standing;

[0075] S2: Start the refrigeration unit 27 and the dehumidifier 33, set the refrigeration temperature of the refrigeration unit 27, close the second control valve 24 and open the first control valve 23, and adjust the temperature of the air cooler 22 and the oil temperature reduction heat exchanger 8 through the fourth control valve 30 and the fifth control valve 31 respectively, so that the intake air temperature and the oil intake temperature meet the test temperature;

[0076] S3: After the engine 2 to be tested has been left to stand, the intake pressure is adjusted to be greater than the atmospheric pressure at the local altitude, and the third control valve 26 is opened to allow the air in the intake passage 16 to exchange heat with the air cooler 22 to drop to the test temperature;

[0077] S4: When the temperature of the air discharged from the ventilation pipe 25 reaches the test temperature, the third control valve 26 is closed to adjust the intake pressure to meet the altitude required for simulation;

[0078] S5: When the intake pressure meets the altitude required to be simulated, the engine 2 to be tested is started to start the test.

[0079] Specifically, the testing method provided in this embodiment specifically includes:

[0080] In step S1, the engine to be tested 2 is placed in the low-temperature environment chamber 1, the air intake passage 16 is connected to the air intake end of the engine to be tested 2, the exhaust passage 17 is connected to the exhaust end of the engine to be tested 2, and the oil inlet pipeline 6 and the oil return pipeline 7 are connected to the oil inlet port and the oil return port of the engine to be tested 2, respectively; then, the low-temperature environment chamber 1 is opened and the temperature of the low-temperature environment chamber 1 is adjusted to the test temperature through the temperature control system 35, and the engine to be tested 2 is left to stand in the low-temperature environment chamber 1;

[0081] In step S2, while the engine 2 to be tested is frozen and kept still, the second control valve 24 is closed and the first control valve 23 is opened to allow the air in the external passage 19 to circulate with the air cooler 22, and the refrigeration unit 27 and the dehumidifier 33 are opened at the same time. The refrigeration unit 27 provides a -50~30°C refrigerant to the first circulation pipeline 28 and the second circulation pipeline 29, and the flow of the refrigerant passing through the air cooler 22 is adjusted by the fourth control valve 30, thereby adjusting the intake air temperature to the test temperature; the flow of the refrigerant passing through the oil temperature reduction heat exchanger 8 is adjusted by the fifth control valve 31, thereby adjusting the intake oil temperature to the test temperature, and dry air is provided by the dehumidifier 33 during this period. The refrigeration temperature of the refrigeration unit 27 should be 5~10°C lower than the test temperature.

[0082] In step S3, after the engine 2 to be tested has been left to stand still, that is, the oil temperature, coolant temperature and fuel temperature of the engine 2 to be tested have all reached the test temperature, the intake pressure is adjusted by the intake fan 12 and the positive pressure regulating valve 14 until the intake pressure is greater than the atmospheric pressure at the local altitude, and then the third control valve 26 is opened. After the third control valve 26 is opened, the air in the inner passage 18 can exchange heat with the air in the air cooler 22 to achieve cooling, until the temperature of the air discharged from the vent pipe 25 reaches the test temperature. The setting of the third control valve 26 is firstly conducive to the circulation of air in the intake passage 16, and secondly, because the air in the intake passage 16 does not circulate when the engine 2 to be tested is not started, the refrigeration efficiency of the air cooler 22 cannot be optimized, and the third control valve 26 can be set to control the intake temperature of the engine 2 to be tested during the low-temperature cold start process to be between ±1°C.

[0083] In step S4, after the temperature of the air discharged from the ventilation pipe 25 reaches the test temperature, the third control valve 26 is closed, and the intake pressure is adjusted to meet the altitude required to be simulated according to the test requirements; when the altitude required to be simulated is greater than the set altitude, it is considered to be in a high-altitude test, the exhaust fan 15 is turned on, and the pressure is adjusted to meet the altitude required to be simulated through the negative pressure regulating valve 13; when the altitude required to be simulated is less than or equal to the set altitude, it is considered to be in a low-altitude test, the intake fan 12 is turned on, and the intake pressure is adjusted to meet the altitude required to be simulated through the positive pressure regulating valve 14; it should be noted that the test altitude is the altitude required to be simulated during the test, and the set altitude is an artificially set limit, and the default is that greater than the set altitude is high altitude, and less than or equal to the set altitude is low altitude.

[0084] In step S5 , when the intake pressure meets the altitude required to be simulated, a cold engine start test is performed on the engine to be tested 2 , and the fuel consumption rate during the cold engine start process is measured by the fuel consumption meter 5 .

[0085] It should be noted that in order to make the intake air temperature meet the following Figure 3 The situation shown needs to be experimented according to the method steps provided in this embodiment.

[0086] Furthermore, while adjusting the temperatures of the air cooler 22 and the oil temperature reduction heat exchanger 8 respectively by the fourth control valve 30 and the fifth control valve 31, the method further includes:

[0087] The temperature of the exhaust temperature heat exchanger 32 is adjusted to cool the exhaust temperature; and the temperature of the oil temperature increase heat exchanger 9 is adjusted to increase the return oil temperature.

[0088] Specifically, the exhaust temperature is reduced by the exhaust temperature heat exchanger 32 to prevent high temperature gas from affecting the state of the exhaust fan 15, thereby improving the efficiency of the exhaust fan 15; the oil temperature increase heat exchanger 9 is used to increase the return oil temperature, thereby reducing the damage of low temperature fuel to the components of the fuel consumption meter 5, and improving the test accuracy. It should be noted that the oil temperature increase heat exchanger 9 realizes temperature control through 30°C circulating water.

[0089] The above description is only a preferred embodiment of the present invention and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present invention is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in the present invention (but not limited to) to form a technical solution.

Claims

1. An engine plateau cold start test system, characterized in that: include: A low temperature environment chamber (1), wherein the low temperature environment chamber (1) is used to place an engine (2) to be tested; An oil supply unit (4), the oil supply unit (4) comprising an oil storage tank (3) and an oil consumption meter (5); the oil storage tank (3) is arranged in the low temperature environment chamber (1) and is used to supply oil to the engine to be tested (2); the oil consumption meter (5) is arranged outside the low temperature environment chamber (1) and is connected to an oil inlet pipeline (6) and an oil return pipeline (7); the oil inlet pipeline (6) is connected to the oil storage tank (3), and the oil return pipeline (7) is used to be connected to the engine to be tested (2); an oil temperature reducing heat exchanger (8) and an oil temperature increasing heat exchanger (9) are respectively provided on the oil inlet pipeline (6) and the oil return pipeline (7); The oil temperature reduction heat exchanger (8) is used to reduce the temperature of the fuel in the oil inlet pipeline (6) to a test temperature before supplying it to the oil storage tank (3), thereby providing accurate oil inlet temperature for the cold start condition, low temperature steady state and transient condition of the engine to be tested (2); An air supply unit (10), the air supply unit (10) comprising an air guide passage (11) disposed outside the low-temperature environment chamber (1), the air guide passage (11) being provided with an air intake fan (12), a negative pressure regulating valve (13), a positive pressure regulating valve (14) and an exhaust fan (15) in sequence, the air guide passage (11) being connected to an air intake passage (16) and an exhaust passage (17) between the negative pressure regulating valve (13) and the positive pressure regulating valve (14), the air intake passage (16) being used to be connected to an air intake end of the engine to be tested (2), and the exhaust passage (17) being used to be connected to an exhaust end of the engine to be tested (2); The air intake passage (16) comprises an inner passage (18) disposed inside the low-temperature environment chamber (1) and an outer passage (19) disposed outside the low-temperature environment chamber (1); The inner passage (18) is provided with a vent pipe (25), the vent pipe (25) being in communication with the inner passage (18) and the outside of the low-temperature environment chamber (1), the vent pipe (25) being provided with a third control valve (26), the vent pipe (25) being used to allow air to circulate and to exchange heat between the air and the air cooler (22).

2. The engine plateau cold start test system according to claim 1, characterized in that: The outer passage (19) is provided with a first node (20) and a second node (21); The air supply unit (10) further comprises: an air cooler (22), the air cooler (22) being connected in parallel between the first node (20) and the second node (21) on the external passage (19) and being used to cool down and regulate the intake air temperature; a first control valve (23), the first control valve (23) being arranged between the first node (20) and the air cooler (22); A second control valve (24), wherein the second control valve (24) is arranged between the first node (20) and the second node (21).

3. The engine plateau cold start test system according to claim 2, characterized in that: The invention also includes a refrigeration unit (27), wherein the refrigeration unit (27) is used to provide a refrigerant; the refrigeration unit (27) is connected to the air cooler (22) via a first circulation pipeline (28), and the refrigeration unit (27) is connected to the oil temperature reduction heat exchanger (8) via a second circulation pipeline (29); the refrigeration unit (27) is used to adjust the temperature of the air cooler (22) and the oil temperature reduction heat exchanger (8) by circulating the refrigerant.

4. The engine plateau cold start test system according to claim 3, characterized in that: The first circulation pipeline (28) is provided with a fourth control valve (30), and the fourth control valve (30) is used to control the flow rate of the refrigerant in the first circulation pipeline (28); the second circulation pipeline (29) is provided with a fifth control valve (31), and the fifth control valve (31) is used to control the flow rate of the refrigerant in the second circulation pipeline (29).

5. The engine plateau cold start test system according to claim 4, characterized in that: The air supply unit (10) further comprises an exhaust temperature heat exchanger (32), wherein the exhaust temperature heat exchanger (32) is used to cool and regulate the exhaust temperature.

6. The engine plateau cold start test system according to claim 5, characterized in that: The air supply unit (10) further comprises a dehumidifier (33), wherein the dehumidifier (33) is arranged on the air intake side of the air intake fan (12).

7. The engine plateau cold start test system according to claim 6, characterized in that: The oil supply unit (4) further comprises a pressure regulating device (34), wherein the pressure regulating device (34) is connected in series to the oil inlet pipeline (6) and the oil return pipeline (7) and is used to regulate the oil inlet pressure and the oil return pressure.

8. A method for testing engine cold start at high altitude, characterized in that: Based on the engine high-altitude cold start test system according to claim 7, the method comprises: Opening the low-temperature environment chamber (1), and placing the engine to be tested (2) in the low-temperature environment chamber (1) to be frozen and left to stand; Starting the refrigeration unit (27) and the dehumidifier (33), setting the refrigeration temperature of the refrigeration unit (27), closing the second control valve (24) and opening the first control valve (23), and adjusting the temperatures of the air cooler (22) and the oil temperature reduction heat exchanger (8) respectively through the fourth control valve (30) and the fifth control valve (31) so that the air intake temperature and the oil intake temperature meet the test temperature; After the engine (2) to be tested has been left to rest, the intake pressure is adjusted to be greater than the atmospheric pressure at the local altitude, and the third control valve (26) is opened to allow the air in the external passage (19) to exchange heat with the air cooler (22) to be reduced to the test temperature; When the temperature of the air discharged from the ventilation pipe (25) reaches the test temperature, the third control valve (26) is closed, and the air intake pressure is adjusted to meet the altitude required to be simulated; When the intake air pressure meets the altitude required to be simulated, the engine to be tested (2) is started to begin the test.

9. The engine plateau cold start test method according to claim 8, characterized in that: While the temperatures of the air cooler (22) and the oil temperature reduction heat exchanger (8) are respectively adjusted by the fourth control valve (30) and the fifth control valve (31), the method further comprises: The temperature of the exhaust temperature heat exchanger (32) is adjusted to reduce the exhaust temperature; and the temperature of the oil temperature increasing heat exchanger (9) is adjusted to increase the return oil temperature.

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