Test system for low-pressure simulation test of cabin type internal combustion engine

Abstract

The utility model provides a cabin type internal combustion engine low-pressure simulation test system which comprises an air inlet pipeline, a test cabin, an exhaust pipeline and a vacuum pump which are communicated in sequence, and an internal combustion engine is arranged in the test cabin; the air inlet pipeline is provided with an air inlet adjusting valve; the exhaust pipeline is provided with an exhaust regulating valve; the exhaust pipeline between the exhaust regulating valve and the vacuum pump is connected with a compensation pipeline, the compensation pipeline is provided with a bypass regulating valve, the exhaust pipeline is also provided with a gas heating device for heating gas, and the gas heating device is positioned between the test cabin and the exhaust regulating valve; the air inlet regulating valve and the air outlet regulating valve are respectively arranged on the air inlet pipeline and the air outlet pipeline of the test chamber, so that the internal air pressure of the test chamber can be regulated, a relatively stable low-pressure environment is formed in the test chamber, the interference of the running internal combustion engine is reduced, and the stability and balance of the air pressure in the test chamber are kept; and the accuracy of test results in the low-pressure simulation test of the internal combustion engine is improved.

Description

Technical Field

[0001] The present application relates to the technical field of internal combustion engine testing, and in particular to a testing system for low-pressure simulation testing of a cabin-type internal combustion engine. Background Art

[0002] At present, internal combustion engines are still vital power equipment in economic construction and national defense security, and play a vital role in national strategic decision-making. Among them, one-third of my country's area is plateau area with high altitude and low air pressure. Therefore, the internal combustion engines used in this area should have good plateau adaptability to meet the corresponding power needs.

[0003] In order to test the working performance of internal combustion engines in plateau areas, low-pressure simulation tests are usually used to study the theory of adaptability of internal combustion engines to plateau environments, and combined with internal combustion engine test platforms, corresponding test means are provided for the demonstration, development, testing and use of the adaptability of internal combustion engines in plateau high-cold environments; since the displacement and working conditions of the internal combustion engine have a great influence on its ventilation volume, when conducting low-pressure simulation tests, it is necessary to accurately and quickly adjust and control the test air pressure of the environmental chamber according to the working conditions of the internal combustion engine to reduce the interference of the internal combustion engine to the low-pressure environment; the internal combustion engine test platform in the relevant technology usually uses a PID (Proportional Integral Derivative) control scheme to adjust the environmental air pressure of the test chamber where the internal combustion engine is located. However, since the adjustment process of this technical means is relatively complicated and the pressure adjustment cycle in the test chamber is relatively long, it is easy to be disturbed by the working conditions of the internal combustion engine during the adjustment process, and it is difficult to maintain the stability and balance of the low-pressure environment in the test chamber, thereby reducing the accuracy of the internal combustion engine test results. Utility Model Content

[0004] In view of this, the purpose of the present application is to propose a test system for low-pressure simulation test of cabin-type internal combustion engines to solve some or all of the technical problems mentioned above.

[0005] Based on the above purpose, the present application provides a test system for a low-pressure simulation test of a cabin-type internal combustion engine, comprising an intake pipeline, a test cabin, an exhaust pipeline and a vacuum pump connected in sequence, wherein an internal combustion engine is arranged in the test cabin;

[0006] The air inlet pipeline is provided with an air inlet regulating valve for regulating the gas flow entering the test chamber; the exhaust pipeline is provided with an exhaust regulating valve for regulating the gas flow discharged from the test chamber; the exhaust pipeline between the exhaust regulating valve and the vacuum pump is connected with a compensation pipeline, and the compensation pipeline is provided with a bypass regulating valve for performing gas compensation on the exhaust pipeline;

[0007] The exhaust pipeline is also provided with a gas heating device for heating the gas, and the gas heating device is located between the test chamber and the exhaust regulating valve.

[0008] From the above, it can be seen that the test system for the low-pressure simulation test of the cabin-type internal combustion engine provided by the present application is provided with an intake regulating valve in the intake pipe of the test cabin, and an outlet regulating valve in the outlet pipe. By adjusting the opening of the intake regulating valve and the outlet regulating valve, the internal air pressure inside the test cabin can be adjusted to form a relatively stable low-pressure environment in the test cabin, reduce the interference of the running internal combustion engine, maintain the stability and balance of the air pressure in the test cabin, and improve the accuracy of the test results in the low-pressure simulation test of the internal combustion engine; and the exhaust pipe is connected to the compensation pipe with a bypass regulating valve, which can compensate the exhaust pipe and ensure that the vacuum pump can continue to operate in a stable state in the low-pressure simulation test, thereby ensuring the smooth progress of the low-pressure simulation test; in addition, the gas heating device can heat the gas passing through the exhaust pipe to avoid the low gas temperature affecting the vacuum degree of the vacuum pump, so as to ensure the extraction efficiency of the vacuum pump. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions in the present application or related technologies, the drawings required for use in the embodiments or related technical descriptions are briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0010] Figure 1 A schematic diagram of a test system for a low-pressure simulation test of a cabin-type internal combustion engine in the present application;

[0011] Figure 2 This is a schematic diagram of the electrical connection relationship of the measurement and control unit in this application;

[0012] Figure 3 This is a flow chart of the test method of the embodiment of the present application;

[0013] Figure 4 This is a flow chart of a method for adjusting the current air pressure difference through an intake regulating valve and a bypass regulating valve in an embodiment of the present application.

[0014] Explanation of the reference numerals: 1. Intake pipe; 101. Intake regulating valve; 2. Test chamber; 3. Exhaust pipe; 301. Exhaust regulating valve; 302. Gas heating device; 4. Vacuum pump; 5. Internal combustion engine; 6. Compensation pipe; 601. Bypass regulating valve; 7. Measurement and control unit; 8. Pressure sensor; 9. Exhaust pipe; 901. Gas pressure stabilizing device; 902. Gas filtering device; 903. Gas cooling device. DETAILED DESCRIPTION

[0015] In order to make the objectives, technical solutions and advantages of the present application more clearly understood, the present application is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0016] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present application should be the usual meanings understood by people with ordinary skills in the field to which the present application belongs. The "first", "second" and similar words used in the embodiments of the present application do not represent any order, quantity or importance, but are only used to distinguish different components. "Including" or "comprising" and similar words mean that the elements or objects appearing in front of the word cover the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0017] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0018] In the related art, in order to test the working performance of internal combustion engines in plateau areas, low-pressure simulation tests are usually used to study the theory of adaptability of internal combustion engines to plateau environments, and combined with internal combustion engine test platforms, corresponding test means are provided for the demonstration, development, testing and use of the adaptability of internal combustion engines in plateau high-cold environments; since the displacement and operating conditions of the internal combustion engine have a great influence on its ventilation volume, when conducting low-pressure simulation tests, it is necessary to accurately and quickly adjust the test air pressure according to the operating conditions of the internal combustion engine to reduce the interference of the internal combustion engine to the low-pressure environment; the internal combustion engine test platform in the related art usually adopts a PID control scheme to adjust the ambient air pressure of the test cabin where the internal combustion engine is located; however, on the one hand, the process of adjusting the air pressure in the test cabin using the PID control scheme is relatively complicated, which prolongs the air pressure adjustment cycle in the test cabin, resulting in a decrease in the adjustment efficiency of the low-pressure environment in the test cabin; on the other hand, when conducting a low-pressure simulation test on the internal combustion engine, the internal air pressure of the test cabin is easily disturbed by the operating conditions of the internal combustion engine, and it is difficult to maintain the stability and balance of the low-pressure environment in the test cabin, thereby reducing the accuracy of the internal combustion engine test results.

[0019] In view of this, the present application provides a test system for a low-pressure simulation test of a cabin-type internal combustion engine 5, comprising an intake pipeline 1, a test cabin 2, an exhaust pipeline 3 and a vacuum pump 4 connected in sequence, wherein an internal combustion engine 5 is arranged in the test cabin 2; the intake pipeline 1 is provided with an intake regulating valve 101 for regulating the gas flow entering the test cabin 2; the exhaust pipeline 3 is provided with an exhaust regulating valve 301 for regulating the gas flow discharged from the test cabin 2; the exhaust pipeline 3 between the exhaust regulating valve 301 and the vacuum pump 4 is connected to a compensation pipeline 6, and the compensation pipeline 6 is provided with a bypass regulating valve 601 for performing gas compensation on the exhaust pipeline 3.

[0020] like Figure 1 and Figure 2 As shown, the present application provides a test system for a low-pressure simulation test of a cabin-type internal combustion engine 5, which is used to quickly and accurately adjust the air pressure in the test cabin 2 to provide a relatively stable low-pressure test environment for the internal combustion engine 5; wherein, the test system comprises an intake pipe 1, a test cabin 2, an exhaust pipe 3 and a vacuum pump 4 which are connected in sequence, and the internal combustion engine 5 is arranged inside the test cabin 2; by changing the intake and exhaust volumes of the test cabin 2, a low-pressure environment can be formed in the test cabin 2 to simulate a use scenario with low air pressure, so as to test the working performance of the internal combustion engine 5 in a low-pressure environment; specifically, the intake end and the exhaust end of the test cabin 2 are respectively The air intake pipe 1 and the air outlet pipe are connected respectively. Since the internal combustion engine 5 consumes a large amount of air pressure during operation, the air intake pipe can be used to replenish gas into the test chamber 2 to avoid excessive gas loss in the test chamber 2 and cause the internal test air pressure to be too low. Sufficient gas can be provided for the internal combustion engine 5 to ensure its normal operation. The air outlet end of the exhaust pipe 3 is connected to the vacuum pump 4. Under the suction action of the vacuum pump 4, the gas in the test chamber 2 can be discharged through the exhaust pipe 3, so that when the air pressure in the test chamber 2 is too high, the test chamber 2 can be quickly depressurized, so as to adjust or maintain the dynamic balance of the low-pressure environment in the test chamber 2.

[0021] In addition, the air intake pipe 1 is provided with an air intake regulating valve 101. By adjusting the opening of the air intake regulating valve 101, the gas flow rate flowing into the test cabin 2 can be changed, so that the gas entering the test cabin 2 meets the requirements of the low-pressure simulation test and the operation requirements of the internal combustion engine 5, and avoids the gas flow rate flowing into the test cabin 2 being too large or too small to cause the low-pressure environment to become unstable; the exhaust pipe 3 is provided with an exhaust regulating valve 301. By adjusting the opening of the exhaust regulating valve 301, the gas flow rate flowing out of the test cabin 2 can be changed, and the pressure can be released in time when the air pressure in the test cabin 2 is too high, thereby realizing precise control of the low-pressure environment in the test cabin 2, and maintaining the balance of the low-pressure environment in the test cabin 2, improving the efficiency of regulating the test air pressure, ensuring that the low-pressure simulation environment is more closely aligned with the air pressure in the real plateau area, and making the test results more accurate.

[0022] In addition, the test system provided in the present application also includes a compensation pipeline 6, the outlet end of which is connected to the exhaust pipeline 3 between the exhaust regulating valve 301 and the vacuum pump 4. Since the test air pressure in the test chamber 2 needs to be continuously and dynamically regulated in the low-pressure simulation test, the vacuum pump 4 in the test system needs to be continuously operated; wherein, when the gas flow rate input into the exhaust pipeline 3 from the test chamber 2 is low, the compensation pipeline 6 can be used to perform gas compensation on the exhaust pipeline 3 connected between the exhaust regulating valve 301 and the vacuum pump 4, and the size of the compensation airflow can be changed by adjusting the bypass regulating valve 601 on the compensation pipeline 6 to ensure that the vacuum pump 4 can operate continuously and stably.

[0023] It should be noted that the air intake regulating valve 101, the exhaust regulating valve 301 and the bypass regulating valve 601 mentioned above all adopt electric gas valves; by adopting electric gas valves, the adjustment speed of the opening of the gas valve itself can be improved, and the adjustment time of the low-pressure environment can be shortened. At the same time, the opening of the gas valve itself can also be accurately adjusted to ensure the accuracy of the pressure environment control in the test cabin 2; the air intake end of the air intake pipeline 1 is connected to an air pump, which is used as a supplementary air source for the test system. The air pump transports gas to the test cabin 2 through the air intake pipeline 1 to replenish the gas to the test cabin 2 in time.

[0024] In some embodiments, the test system also includes a measurement and control unit 7, which is electrically connected to the intake regulating valve 101, the exhaust regulating valve 301 and the bypass regulating valve 601, respectively, and is used to control the intake regulating valve 101, the exhaust regulating valve 301 and the bypass regulating valve 601 to adjust their respective openings; and also includes a pressure sensor 8 for detecting the gas pressure in the test chamber 2, and the pressure sensor 8 is arranged inside the test chamber 2 and is electrically connected to the measurement and control unit 7.

[0025] like Figure 2 As shown, the test system also includes a measurement and control unit 7, wherein the measurement and control unit 7 is electrically connected to the intake regulating valve 101, the exhaust regulating valve 301 and the bypass regulating valve 601, respectively, and is used to control the intake regulating valve 101, the exhaust regulating valve 301 and the bypass regulating valve 601 to adjust their own openings, so as to realize the automatic adjustment of the test system and ensure the stability and balance of the low-pressure environment in the test cabin 2; and in the test system, it also includes a pressure sensor 8 arranged in the test cabin 2, by which the air pressure information in the test cabin 2 can be collected in real time, and the collected air pressure information can be sent to the measurement and control unit 7. After receiving the air pressure information of the test cabin 2, the measurement and control unit 7 adjusts the intake regulating valve 101, the exhaust regulating valve 301 and the bypass regulating valve 601 to adjust the appropriate opening according to the current air pressure information in the test cabin 2, so as to adjust the intake and exhaust conditions in the test cabin 2, ensure that the actual air pressure in the test cabin 2 always meets the test requirements, and improve the accuracy of the test results in the low-pressure simulation test.

[0026] For example, when the test air pressure in the test chamber 2 is adjusted, the pressure sensor 8 disposed inside the test chamber 2 collects the air pressure information of the test air pressure, and sends the acquired air pressure information to the measurement and control unit 7 in a wired or wireless manner; after receiving the air pressure information, the measurement and control unit 7 can control the intake regulating valve 101, the exhaust regulating valve 301 and the bypass regulating valve 601 to adjust their respective openings according to the received air pressure information, change the gas flow rate flowing into the test chamber 2 through the intake pipe 1 by adjusting the opening of the intake regulating valve 101, and adjust the gas flow rate flowing into the test chamber 2 through the exhaust pipe 3 by adjusting the opening of the exhaust regulating valve 301. The gas flow out of the test chamber 2 can realize the rapid adjustment of the test air pressure in the test chamber 2, maintain the dynamic balance of the low-pressure environment in the test chamber 2, and ensure the accuracy of the test air pressure adjustment; and in the low-pressure simulation test process, in order to ensure that the test chamber 2 always maintains a stable low-pressure environment, it is necessary to continuously adjust the test air pressure in the test chamber 2, so it is necessary to keep the vacuum pump 4 in operation. When the gas flow in the exhaust pipe 3 is small, the compensation pipe 6 can be used to supplement the air flow in the exhaust pipe 3, and the bypass regulating valve 601 set in the compensation pipe 6 can be used to change the size of the compensation air flow to ensure the stability of the operation of the vacuum pump 4.

[0027] In addition, multiple pressure sensors 8 can be set in the test cabin 2; since the internal combustion engine 5 is located inside the test cabin 2, and the internal combustion engine 5 needs to consume the gas in the test cabin 2 during operation, therefore, by setting up multiple pressure sensors 8 and making the multiple pressure sensors 8 evenly distributed in the test cabin 2, it is possible to collect pressure information at different positions in the test cabin 2, thereby obtaining the pressure distribution in the test cabin 2. When the measurement and control unit 7 detects through multiple pressure sensors 8 that the test air pressure in the test cabin 2 is poorly uniform, it means that the low-pressure environment simulated in the test cabin 2 deviates greatly from the low-pressure environment in the real plateau area, and the accuracy of the obtained test results is low. Therefore, the test personnel are required to adjust the test air pressure in the test cabin 2 in time.

[0028] In some embodiments, the exhaust pipeline 3 is further provided with a gas heating device 302 for heating the gas. The gas heating device 302 is located between the test chamber 2 and the exhaust regulating valve 301 and is electrically connected to the measurement and control unit 7 .

[0029] like Figure 1As shown, since it is necessary to simulate the low-pressure environment of the plateau area in the test cabin 2, the air pressure in the test cabin 2 is relatively low, and the temperature of the gas discharged through the exhaust pipe 3 is also relatively low; when the gas with a lower temperature enters the vacuum pump 4 through the exhaust pipe 3, the temperature of the vacuum pump 4 is rapidly reduced, and liquefaction is likely to occur inside the vacuum pump 4, affecting the vacuum degree and mechanical properties of the vacuum pump 4, thereby reducing the extraction efficiency of the vacuum pump 4; therefore, by providing a gas heating device 302 in the exhaust pipe 3 between the test cabin 2 and the vacuum pump 4, and electrically connecting the measurement and control unit 7 to the gas heating device 302, the gas can be heated, the gas temperature in the exhaust pipe 3 is increased, and the impact on the performance of the vacuum pump 4 is reduced.

[0030] In some embodiments, the exhaust pipe 3 between the gas heating device 302 and the exhaust regulating valve 301 is connected to the internal combustion engine 5 through an exhaust pipe 9; the exhaust pipe 9 is provided with a gas pressure stabilizing device 901 for regulating the pressure of the exhaust gas discharged from the internal combustion engine 5.

[0031] like Figure 1 As shown, the exhaust gas pipeline 9 is connected to the internal combustion engine 5, and is used to transport the gas generated by the internal combustion engine 5 to the outside of the test chamber 2, so as to prevent the exhaust gas generated by the internal combustion engine 5 from destroying the low-pressure environment in the test chamber 2; at the same time, the exhaust gas pipeline 9 is connected to the exhaust pipeline 3, and the outlet end of the exhaust pipeline 3 is connected to the vacuum pump 4, so that the gas in the exhaust pipeline 3 and the exhaust gas in the exhaust pipeline 9 can be exhausted by the same vacuum pump 4, simplifying the overall structure of the test system and reducing the manufacturing cost of the equipment; at the same time, since the exhaust gas pressure of the internal combustion engine 5 is relatively high during operation, and there is a certain pressure difference with the exhaust gas pressure in the exhaust pipeline 3, it is not easy to be discharged smoothly through the exhaust pipeline 3; therefore, by arranging a gas pressure stabilizing device 901 in the exhaust gas pipeline 9, the exhaust gas pressure in the exhaust gas pipeline 9 can be adjusted, so that the exhaust gas pressure in the exhaust gas pipeline 9 is close to the exhaust gas pressure in the exhaust pipeline 3, so that the vacuum pump 4 can simultaneously extract the exhaust gas in the exhaust pipeline 3 and the exhaust gas in the exhaust pipeline 9.

[0032] In some embodiments, the exhaust gas pipeline 9 is further provided with a gas filter device 902 for filtering the exhaust gas of the internal combustion engine 5, and the gas filter device 902 is arranged between the internal combustion engine 5 and the gas pressure stabilizing device 901;

[0033] like Figure 1As shown, since the internal combustion engine 5 uses fuel oil as a power fuel, impurities such as water vapor and smoke particles are generated during the operation of the internal combustion engine 5, and when the vacuum pump 4 is used for extraction, the impurities are easily attached to the inside of the vacuum pump 4 and cause the vacuum pump 4 to be blocked, thereby affecting the extraction capacity of the vacuum pump 4; by arranging a gas filter device 902 on the exhaust gas pipeline 9, the exhaust gas passing through the exhaust gas pipeline 9 can be adsorbed and filtered, so as to remove impurities such as moisture and smoke particles in the exhaust gas before the exhaust gas is merged into the exhaust pipeline 3, thereby reducing the impact of the exhaust gas on the vacuum pump 4 and ensuring that the vacuum pump 4 can operate stably.

[0034] In some embodiments, the exhaust gas pipeline 9 is further provided with a gas cooling device 903 for cooling the exhaust gas of the internal combustion engine 5 . The gas cooling device 903 is arranged between the internal combustion engine 5 and the gas filtering device 902 , and is electrically connected to the measurement and control unit 7 .

[0035] like Figure 1 As shown, since the exhaust gas temperature generated by the internal combustion engine 5 is relatively high, when the exhaust gas with a relatively high temperature flows into the exhaust pipe 3, the temperature of the gas in the exhaust pipe 3 will gradually increase. If the vacuum pump 4 pumps out the gas with a relatively high temperature for a long time, it is easy to increase the working temperature of the vacuum pump 4, thereby reducing the gas pumping efficiency of the vacuum pump 4; therefore, by arranging a gas cooling device 903 in the exhaust gas pipe 9, the exhaust gas generated by the internal combustion engine can be cooled, and the temperature of the exhaust gas flowing into the exhaust pipe 3 can be reduced, so as to ensure that the vacuum pump 4 has a good operating environment.

[0036] In some embodiments, a sealing component (not marked in the figure) for sealing is provided between the test chamber 2 and the exhaust gas pipe 9; for the test system, since the internal combustion engine 5 is arranged inside the test chamber 2, it is necessary to use the exhaust gas pipe 9 to discharge the exhaust gas generated by the internal combustion engine 5; wherein, by providing a sealing component between the exhaust gas pipe 9 and the test chamber 2, the airtightness of the test chamber 2 can be ensured, and gas leakage in the test chamber 2 can be avoided.

[0037] Based on the same concept, the present application also provides a test method for a cabin-type internal combustion engine 5 test platform, which is applicable to a test system as in any of the above embodiments, such as Figure 3 As shown, the test methods include:

[0038] Step S100: Control the air intake regulating valve 101, the exhaust regulating valve 301 and the bypass regulating valve 601 to open, and control the vacuum pump 4 to start, to obtain the actual air pressure in the test chamber 2, wherein the openings of the bypass regulating valve 601 and the air intake regulating valve 101 are both smaller than the opening of the exhaust regulating valve 301;

[0039] In this step, when testing the working performance of the internal combustion engine 5 in the low-pressure simulation test, the test system is started to open the intake regulating valve 101, the exhaust regulating valve 301 and the bypass regulating valve 601 in the pressure controller system, and the intake pipe 1, the exhaust pipe 3 and the bypass pipe connected to the test chamber 2 are connected; the vacuum pump 4 is controlled to start so that the vacuum pump 4 exhausts the gas in the test chamber 2 through the exhaust pipe 3, so that the internal air pressure of the test chamber 2 is gradually reduced; during this period, the actual air pressure in the test chamber 2 can be obtained in real time, and it is determined whether the current low-pressure simulation test requirements of the internal combustion engine 5 are met based on the actual air pressure obtained.

[0040] It should be noted that before conducting the low-pressure simulation test, in order to shorten the time for forming a low-pressure environment, it is necessary to quickly reduce the air pressure in the test chamber 2. At this time, the opening of the air intake regulating valve 101 can be controlled to be smaller than the opening of the exhaust regulating valve 301, so that the air intake volume of the test chamber 2 is smaller than its exhaust volume. Under the pumping action of the vacuum pump 4, the speed of reducing the air pressure in the test chamber is accelerated; at the same time, since the gas flow in the exhaust pipeline 3 is large at this time, there is no need to compensate the gas to the exhaust pipeline 3 through the compensation pipeline 6, so the opening of the bypass regulating valve 601 can be made smaller than the opening of the exhaust regulating valve 301, or it can be kept closed to avoid excessive load on the vacuum pump 4; illustratively, when controlling the air intake regulating valve 101, the exhaust regulating valve 301 and the bypass regulating valve 601 to be opened, the opening of the air intake regulating valve 101 can be made 30%, the opening of the exhaust regulating valve 301 can be made 100%, and the opening of the bypass regulating valve 601 can be made 30%, so that the air pressure in the test chamber 2 can drop quickly and steadily.

[0041] Step S200: determining the current air pressure difference according to the actual air pressure and the preset air pressure threshold, and adjusting the opening of the air intake regulating valve 101 and the bypass regulating valve 601 based on the current air pressure difference and the preset control rule to adjust the actual air pressure in the current test chamber 2, wherein the preset control rule is to compare the current air pressure difference with the first preset air pressure difference threshold and the second preset air pressure difference threshold, respectively, and the first preset air pressure difference threshold is less than the second preset air pressure difference threshold;

[0042] In this step, after obtaining the actual air pressure in the test chamber 2, the current air pressure difference between the actual air pressure obtained and the preset air pressure threshold is determined. After obtaining the current air pressure, the opening of the air intake regulating valve 101 and the bypass regulating valve 601 are controlled based on the preset control rules. By adjusting the opening of the air intake regulating valve 101, the gas flow entering the test chamber 2 is adjusted to supplement the internal combustion engine 5 with the gas required for operation and to adjust the test air pressure in the test chamber 2; and by adjusting the opening of the bypass regulating valve 601, the gas pressure in the exhaust pipe 3 can be compensated to ensure that the vacuum pump 4 can operate stably.

[0043] It should be noted that the current air pressure difference mentioned above can be the difference between the actual air pressure and the preset air pressure threshold, and the pre-set preset control rule can be to compare the current air pressure difference with the first preset air pressure difference threshold and the second preset air pressure difference threshold respectively, and make the first preset air pressure difference threshold smaller than the second preset air pressure difference threshold, so as to adjust the opening of the air intake regulating valve 101 according to the size relationship between the current air pressure difference and the first preset air pressure difference threshold, and the size relationship between the current air pressure difference and the second preset air pressure difference threshold, until the current air pressure difference in the test chamber 2 meets the test requirements of the low-pressure simulation test.

[0044] Step S300: when it is determined that the current air pressure difference is greater than the first preset air pressure difference threshold and less than the second preset air pressure difference threshold, the internal combustion engine 5 is controlled to start and run for a preset time, the current air pressure difference is calibrated by adjusting the opening of the intake regulating valve 101, and the working performance of the internal combustion engine 5 is tested;

[0045] In this step, the test system is adjusted by using the air intake regulating valve 101 and the bypass regulating valve 601 until a low-pressure environment that meets the low-pressure simulation test is adjusted in the test cabin 2; wherein, when the current air pressure difference in the test cabin 2 is greater than the first preset air pressure difference threshold and less than the second preset air pressure difference threshold, it means that the actual air pressure in the test cabin 2 meets the test requirements of the low-pressure simulation test and is consistent with the low-pressure environment of the real plateau area; at this time, the internal combustion engine 5 is controlled to start and run. Since the internal combustion engine 5 consumes the gas in the test cabin 2 during the startup process, the test cabin 2 will be The actual air pressure inside the test chamber 2 drops. At this time, the actual air pressure inside the test chamber 2 can be adjusted by adjusting the opening of the air intake regulating valve 101, that is, the current air pressure difference is calibrated to make the current air pressure difference meet the test requirements of the low-pressure simulation test again, so as to avoid affecting the balance of the low-pressure environment in the test chamber 2 due to the start of the internal combustion engine 5; and when the internal combustion engine 5 has run for a preset time, the working performance of the internal combustion engine 5 is tested again. At this time, the operating condition of the internal combustion engine 5 tends to be stable, and at the same time, the adjustment time of the low-pressure environment is reserved to ensure the accuracy of the test results in the low-pressure simulation test.

[0046] Exemplarily, in the above, the current air pressure difference can be set to ΔP, the first preset air pressure difference threshold can be -0.3kPa, and the second preset air pressure difference threshold can be 0.3kPa. When the current air pressure difference is greater than -0.3kP and less than 0.3kPa, that is, -0.3kPa<ΔP<0.3kPa, it means that the actual air pressure in the test chamber 2 is not much different from the preset air pressure threshold, and has little impact on the test results of the low-pressure simulation test, which meets the test requirements of the low-pressure simulation test. Therefore, the performance of the internal combustion engine 5 can be tested; at this time, the internal combustion engine 5 is controlled to start and run for 2-3 minutes. During this period, the opening of the intake regulating valve 101 can be adjusted at a rate of 0.06% per second to avoid affecting the accuracy of the opening adjustment of the intake regulating valve 101 due to too fast adjustment, until the actual air pressure in the test chamber 2 is close to the preset air pressure threshold and tends to be stable, and the current air pressure difference meets the test requirements of the low-pressure simulation test.

[0047] Step S400: when it is determined that the working performance of the internal combustion engine 5 has been tested, the intake regulating valve 101 is controlled to be adjusted to the first preset opening, the exhaust regulating valve 301 is closed, the bypass regulating valve 601 is adjusted to the second preset opening, and the current air pressure in the test chamber 2 is obtained;

[0048] In this step, after the working performance of the internal combustion engine 5 is tested using the test system, it is necessary to pressurize the test chamber 2 to reduce the burden on the test chamber 2; specifically, the intake regulating valve 101 is controlled to be adjusted to a first preset opening, the exhaust regulating valve 301 is closed, and the bypass regulating valve 601 is adjusted to a second preset opening, for example, the first preset opening can be 50%, that is, the opening of the intake regulating valve 101 is adjusted to 50%, so that the gas can quickly enter the test chamber 2 through the intake pipe 1 and the intake regulating valve 101, thereby making the test air pressure in the test chamber 2 rise quickly and stably, changing the low-pressure environment during the test; at the same time, by adjusting the bypass regulating valve 601 to the second preset opening, for example, the second preset opening can be 50%, that is, the opening of the bypass regulating valve 601 can be adjusted to 50%, so as to compensate the exhaust pipe 3 for gas through the compensation pipe 6, ensure that the exhaust gas in the exhaust pipe 9 is fully discharged, and ensure that the vacuum pump 4 can operate stably.

[0049] Step S500: When it is determined that the current air pressure is greater than or equal to the preset pressure stabilization threshold, the internal combustion engine 5 is controlled to stop running, and the vacuum pump 4 is controlled to be turned off.

[0050] In this step, the current air pressure in the test cabin 2 is obtained in real time. When it is determined that the current air pressure in the test cabin 2 is greater than or equal to the preset stable air pressure, it means that the current air pressure is not much different from the external air pressure and tends to be stable, and will not affect the reuse of the test cabin 2. At this time, the internal combustion engine 5 is controlled to stop running, and the vacuum pump 4 is controlled to be turned off, thereby ending the low-pressure simulation test of the internal combustion engine 5; illustratively, the preset stable air pressure can be set to 95kPa, that is, when the current air pressure in the test cabin 2 is greater than or equal to 95kPa, the internal and external air pressures in the test cabin 2 tend to be relatively stable.

[0051] In some embodiments, the openings of the intake regulating valve 101 and the bypass regulating valve 601 are regulated based on the current pressure difference and the preset regulation rules, such as Figure 4 As shown, including:

[0052] Step S210: when it is determined that the current air pressure difference is less than or equal to the first preset air pressure difference threshold, the intake regulating valve 101 and the bypass regulating valve 601 are respectively controlled to increase their openings;

[0053] In this step, after obtaining the current air pressure difference, the openings of the air intake regulating valve 101 and the bypass regulating valve 601 are regulated according to the current air pressure difference and the preset control rules, and the air intake regulating valve 101 and the bypass regulating valve 601 are used to change the test air pressure in the test cabin 2 until a low-pressure environment that meets the low-pressure simulation test is adjusted in the test cabin 2; if the current air pressure difference is less than or equal to the first preset air pressure difference threshold, such as ΔP≤0.3kPa, it means that the actual air pressure in the test cabin 2 is less than the preset air pressure threshold and the deviation is large, and the fit with the low-pressure environment in the real plateau area is low, which does not meet the test of the low-pressure simulation test. Requirements; at this time, control the air intake regulating valve 101 to increase its opening, speed up the air intake speed in the test chamber 2, so that the actual air pressure in the test chamber 2 gradually rises, until the current air pressure difference is greater than the first preset air pressure difference threshold and less than the second preset air pressure difference threshold, so that the actual air pressure inside the test chamber 2 meets the low-pressure simulation test requirements; at the same time, since the air pressure in the test chamber 2 is relatively low, the gas flow in the exhaust pipe 3 may also be relatively small. At this time, the bypass regulating valve 601 can be appropriately adjusted to properly compensate the gas in the exhaust pipe 3 through the compensation pipe 6 to ensure the stability of the vacuum pump 4 exhaust.

[0054] Step S220: When it is determined that the current pressure difference is greater than or equal to the second preset pressure difference threshold, the intake regulating valve 101 is controlled to be opened less, and the bypass regulating valve 601 is controlled to be opened less or closed.

[0055] In this step, if the current air pressure difference is greater than or equal to the first preset air pressure difference threshold, such as ΔP ≥ 0.3 kPa, it means that the actual air pressure in the test cabin 2 is greater than the preset air pressure threshold and the deviation is large, and the degree of fit with the low-pressure environment of the actual plateau area is low, which does not meet the test requirements of the low-pressure simulation test; at this time, the air intake regulating valve 101 is controlled to adjust its opening to reduce the air intake speed in the test cabin 2, so that the actual air pressure in the test cabin 2 gradually decreases until the current air pressure difference is greater than the first preset air pressure difference threshold and less than the second preset air pressure difference threshold, so that the actual air pressure inside the test cabin 2 meets the requirements of the low-pressure simulation test; at the same time, since the air pressure in the test cabin 2 is relatively large, the gas flow in the exhaust pipe 3 may also be relatively large. At this time, there is no need to compensate for the gas in the exhaust pipe 3, so the opening of the bypass regulating valve 601 can be controlled to be reduced or closed to avoid overloading the vacuum pump 4.

[0056] In some embodiments, the control method further includes: when the working state of the internal combustion engine 5 is changed, re-obtaining the actual air pressure in the test chamber 2, and determining a new current air pressure difference based on the re-obtained actual air pressure and a preset air pressure threshold.

[0057] Specifically, during the low-pressure simulation test, it is necessary to adjust the opening of the intake regulating valve 101 and the bypass regulating valve 601 based on the current air pressure difference and the preset control rules to make the actual air pressure in the test chamber 2 meet the test requirements of the low-pressure simulation test. Therefore, when the working state of the internal combustion engine 5 is changed, the ventilation volume of the internal combustion engine 5 during operation changes, resulting in changes in the actual air pressure in the test chamber 2. Therefore, it is necessary to re-acquire the actual air pressure in the test chamber 2, and then determine a new current air pressure difference based on the re-acquired actual air pressure and the preset air pressure threshold. Then, use the new current air pressure difference to determine whether the actual air pressure in the test chamber 2 meets the test requirements of the low-pressure simulation test. If not, use the intake regulating valve 101 and the bypass regulating valve 601 to readjust the actual air pressure in the test chamber 2 to ensure the accuracy of the test results.

[0058] In some embodiments, the control method further includes: when the preset air pressure threshold is updated, determining a new current air pressure difference according to the actual air pressure and the updated preset air pressure threshold.

[0059] Specifically, during the low-pressure simulation test, when the preset air pressure threshold is updated, the current test difference between the actual air pressure in the test chamber 2 and the updated preset air pressure threshold changes, and therefore it is necessary to re-determine whether the new current test difference meets the test requirements of the low-pressure simulation test; specifically, the current air pressure difference is re-judged based on the preset control rules, and when the new current air pressure difference is less than or equal to the first preset air pressure difference threshold, or greater than or equal to the second preset air pressure difference threshold, the air intake regulating valve 101 and the bypass regulating valve 601 are used to re-adjust the actual air pressure in the test chamber 2 to ensure the accuracy of the test results.

[0060] It should be noted that the above describes some embodiments of the present application. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the above embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0061] The various embodiments in the present application are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0062] The description of the present application is given for the purpose of illustration and description, and is not intended to be exhaustive or to limit the present application to the disclosed form. Many modifications and variations are obvious to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present application, and to enable those of ordinary skill in the art to understand the present application and thus design various embodiments with various modifications suitable for specific purposes.

[0063] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the present application (including the claims) is limited to these examples. In line with the concept of the present application, the technical features in the above embodiments or different embodiments may be combined, the steps may be implemented in any order, and there are many other variations of the different aspects of the embodiments of the present application as described above, which are not provided in detail for the sake of simplicity.

[0064] Although the present application has been described in conjunction with specific embodiments thereof, many alternatives, modifications and variations of these embodiments will be apparent to those skilled in the art in light of the foregoing description.

[0065] The embodiments of the present application are intended to cover all such substitutions, modifications and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present application should be included in the scope of protection of the present application.

Claims

1. A test system for low-pressure simulation test of cabin internal combustion engines, characterized in that: It includes an air intake pipeline, a test chamber, an exhaust pipeline and a vacuum pump which are connected in sequence, and an internal combustion engine is arranged in the test chamber; The air inlet pipeline is provided with an air inlet regulating valve for regulating the gas flow entering the test chamber; the exhaust pipeline is provided with an exhaust regulating valve for regulating the gas flow discharged from the test chamber; the exhaust pipeline between the exhaust regulating valve and the vacuum pump is connected with a compensation pipeline, and the compensation pipeline is provided with a bypass regulating valve for performing gas compensation on the exhaust pipeline; The exhaust pipeline is also provided with a gas heating device for heating the gas, and the gas heating device is located between the test chamber and the exhaust regulating valve.

2. The test system for low-pressure simulation test of cabin internal combustion engine according to claim 1, characterized in that: It also includes a measurement and control unit, which is electrically connected to the intake regulating valve, the exhaust regulating valve and the bypass regulating valve respectively, and is used to control the intake regulating valve, the exhaust regulating valve and the bypass regulating valve to adjust their respective openings.

3. The test system for low-pressure simulation test of cabin internal combustion engine according to claim 2, characterized in that: It also includes a pressure sensor for detecting the gas pressure in the test chamber. The pressure sensor is arranged inside the test chamber and is electrically connected to the measurement and control unit.

4. The test system for low-pressure simulation test of cabin internal combustion engine according to claim 3, characterized in that: A plurality of pressure sensors are provided.

5. The test system for low-pressure simulation test of cabin internal combustion engine according to claim 1, characterized in that: The air inlet end of the air inlet pipeline is connected to an air pump, and the air pump delivers gas to the test chamber through the air inlet pipeline.

6. The test system for low-pressure simulation test of cabin internal combustion engine according to claim 1, characterized in that: The internal combustion engine is connected to an exhaust gas pipeline, and the exhaust gas pipeline between the gas heating device and the exhaust regulating valve is connected to the exhaust gas pipeline; the exhaust gas pipeline is provided with a gas pressure stabilizing device for regulating the pressure of the exhaust gas discharged from the internal combustion engine.

7. The test system for low-pressure simulation test of cabin internal combustion engine according to claim 6, characterized in that: The exhaust gas pipeline is also provided with a gas filtering device for filtering the exhaust gas of the internal combustion engine, and the gas filtering device is arranged between the internal combustion engine and the gas pressure stabilizing device.

8. The test system for low-pressure simulation test of cabin internal combustion engines according to claim 7, characterized in that: The exhaust gas pipeline is further provided with a gas cooling device for cooling the exhaust gas of the internal combustion engine, and the gas cooling device is arranged between the internal combustion engine and the gas filtering device.

9. The test system for low-pressure simulation test of cabin internal combustion engine according to claim 6, characterized in that: A sealing component for sealing is arranged between the test chamber and the exhaust gas pipeline.

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