A method for automatically spraying water to cool high-temperature exhaust gas in an engine combustion chamber tester

Abstract

The present application discloses a method for controlling automatic water spray cooling of high-temperature exhaust gas of an engine combustion chamber tester. The method is based on a high-temperature exhaust gas water spray system. The method is based on the hardware of a high-pressure cooling water system. By automatically controlling a water inlet regulating valve and two water return regulating valves, the method controls the cooling water sprayed into the water jacket of the test piece cabin to change the appropriate flow value under different working conditions, so as to achieve the purpose of cooling the high-temperature exhaust gas of the engine combustion chamber tester to a set value. In the absence of dedicated monitoring, the method automatically executes a response action according to the current exhaust gas temperature, so that the exhaust temperature is effectively reduced. The exhaust gas temperature of the high-temperature exhaust gas water spray cooling system of the existing engine combustion chamber is automatically reduced to 150°C~200°C without manual monitoring after the control method. It can not only ensure that it is below 300°C, but also effectively control the injection flow rate to ensure that it is just vaporized without water accumulation, thereby meeting the two requirements of energy saving and consumption reduction and rapid cooling at the same time.

Description

Technical Field

[0001] The present application relates to the technical field of cooling control of engine combustion chamber testers, and in particular, to an automatic water spray cooling control method for high-temperature exhaust gas of an engine combustion chamber tester. Background Art

[0002] The exhaust gas temperature generated by the engine combustion chamber ground parts and components tester during the heating test is as high as 1800℃. If it is directly discharged to the rear pipeline through the exhaust valve without cooling, it will easily burn the insulation layer, seriously reduce the life of the valve and exhaust pipeline, and cause direct damage to the tester equipment.

[0003] The existing high-temperature exhaust gas water spray cooling system of the engine combustion chamber is mostly manually operated or simply automatically switched on and off. The former is completely manual, which not only consumes extra manpower, but also carries more risks of manual observation and operation errors. If the water spray volume does not change in time, it will seriously affect the safety of the equipment; the latter relies on the system to detect the current exhaust gas temperature in real time. Once the warning value (such as 300°C) is reached, the water spray pump will automatically run or the water spray valve will be opened for cooling, but the spray flow rate cannot be effectively controlled. If the water spray volume is too large, water will easily accumulate in the exhaust pipe and form a leak. If the water spray volume is too small, the gas temperature will be too high and the exhaust equipment will be damaged. Summary of the invention

[0004] The present application provides an automatic water spray cooling control method for high-temperature exhaust gas of an engine combustion chamber tester, so as to solve the technical problems that the existing high-temperature exhaust gas water spray cooling technology of the engine combustion chamber is labor-intensive and unsafe, and the inaccurate water spraying amount leads to water accumulation and damage to the exhaust equipment.

[0005] This application is implemented through the following scheme:

[0006] A method for automatically spraying water to cool high-temperature exhaust gas of an engine combustion chamber tester is provided. The method is based on a high-temperature exhaust gas spraying system. The high-temperature exhaust gas spraying system comprises a water reservoir, a manual valve, a filter, a high-pressure centrifugal water pump, a check valve, a water inlet regulating valve, a high-pressure water spraying rod, a large return water regulating valve, a small return water regulating valve, and an overflow valve. The input end of the high-pressure centrifugal water pump is connected to the filter, the manual valve, and the water reservoir in sequence. The output end of the high-pressure centrifugal water pump is connected to the check valve, the large return water regulating valve, the small return water regulating valve, and the input end of the overflow valve respectively. The output end of the overflow valve is connected to the input end of the high-pressure centrifugal water pump. The output ends of the large return water regulating valve and the small return water regulating valve are connected to the water reservoir. The output end of the check valve is connected to the water inlet regulating valve and the high-pressure water spraying rod in sequence. The high-pressure water spraying rod sprays water into the water jacket in the test specimen cabin. The method comprises the following steps:

[0007] S1. Before turning on the automatic control function, keep the opening of the water inlet regulating valve at 0%, the opening of the large return water regulating valve and the small return water regulating valve at 100%, and then turn on the high-pressure centrifugal water pump;

[0008] S2, set the pressure difference target value P respectively w差0 and the target temperature of the specimen in the cabin T t舱0 , where the pressure difference target value P w差0 Output pressure P of the water inlet regulating valve W水 The pressure P in the test chamber s舱 Difference P w差 The target value is greater than 0;

[0009] S3. Calculate the theoretical high-pressure cooling water flow rate W based on the heat that high-pressure water needs to absorb and the heat that 1 kg of water needs to absorb when it is completely vaporized from the inlet water temperature and heated to the required temperature after cooling under the maximum pressure of the combustion chamber outlet gas. a水0 , the PID input value for adjusting the opening of the water inlet regulating valve remains unchanged;

[0010] S4. Directly based on T t舱0 The setting value performs PID adjustment on the opening of the small return water regulating valve, so that the small return water regulating valve moves to the exhaust temperature T of the test piece. t舱 = Target value of the test piece temperature in the chamber T t舱0 ;

[0011] S5, automatically control the opening of the large return water regulating valve, so that P w差 Maintain at set value;

[0012] S6. Through corresponding adjustment methods, wait until the water inlet regulating valve, large return water regulating valve, and small return water regulating valve all enter the stage where the opening does not change or the opening change is less than the preset value, and the measured exhaust temperature T t舱 and the target temperature value T of the specimen in the cabin t舱0 When the difference between them is less than the preset value and maintained for the set time, and meets the set steady-state accuracy requirements, the high-temperature exhaust gas water spray system is judged to have reached a steady state. Finally, the large return water regulating valve, the small return water regulating valve, and the water inlet regulating valve are automatically controlled to make the high-pressure water spray rod spray water into the water jacket in the test specimen cabin to reduce the high-temperature exhaust gas to the target temperature.

[0013] Furthermore, in step S2, the pressure difference target value P is set. w差0 ∈(0.1~0.5)Mpa, set the target temperature value T of the test piece in the chamber t舱0 =150℃±5℃.

[0014] Furthermore, the step S3 specifically includes the steps of:

[0015] Calculate the heat that high pressure water needs to absorb:

[0016] Q=m a (C p1 ×T1-C p2 ×T2)

[0017] In the formula, Q is the heat absorbed by high-pressure water, that is, the heat released by high-temperature gas, m a is the mass of high temperature fuel gas, C p1 is the constant pressure specific heat of high temperature gas before cooling, C p2 is the constant pressure specific heat of the high temperature gas after cooling, T1 is the initial temperature of the high temperature gas, and T2 is the temperature of the high temperature gas after cooling;

[0018] Calculate the heat Q1 that needs to be absorbed when 1 kg of high-pressure water is completely vaporized from the inlet temperature and heated to the required temperature after cooling under the maximum pressure of the combustion chamber outlet gas:

[0019] Q1= h1- h2

[0020] Wherein, h1 is the enthalpy value of water vapor at the required cooling temperature when the combustion chamber outlet gas pressure is maximum; h2 is the enthalpy value of liquid water at the inlet water temperature when the combustion chamber outlet gas pressure is maximum;

[0021] Combining the above formulas, we get:

[0022] Q=m a (C p1 ×T1-C p2 ×T2) = h1- h2

[0023] Thus, the theoretical high-pressure cooling water flow rate W is obtained a水0 , the PID input value for adjusting the opening of the water inlet regulating valve remains unchanged to control the output flow of the water inlet regulating valve.

[0024] Furthermore, the theoretical high-pressure cooling water flow rate W is calculated a水0 Then, the theoretical high-pressure cooling water flow W a水0 ×1.2 as the PID input value for adjusting the opening of the water inlet regulating valve remains unchanged.

[0025] Further, in step S5, if the opening of the large return water regulating valve is automatically controlled, P w差 If the flow rate and temperature meet the requirements, the small return water regulating valve is manually adjusted to close the opening to make P w差 Maintain at set value.

[0026] Further, in step S5, when controlling the opening of the large return water regulating valve, the valve position of the large return water regulating valve is given by adopting the empirical fitting curve, so that P w差 Maintain at set value.

[0027] Furthermore, in step S6, the set steady-state accuracy is ±0.5%.

[0028] Furthermore, a liquid level controller is also provided in the water reservoir, and the liquid level controller is used to control the water inlet solenoid valve according to the water level in the water reservoir to maintain the water volume in the water reservoir.

[0029] Furthermore, the method further comprises the steps of:

[0030] S7, when the target temperature of the test piece in the chamber is set to T t舱0 If a change occurs, the control process of steps S3 to S6 is repeated, and water is sprayed into the water jacket in the test chamber to reduce the high-temperature exhaust gas to the target temperature.

[0031] Further, the method further comprises the steps of:

[0032] S8. If the measured exhaust temperature of the test piece is T t舱 and the target temperature value T of the specimen in the cabin t舱0 When the difference between the two is greater than the preset value and is maintained for the set time, if the measured exhaust temperature T t舱 and the target temperature value T of the specimen in the cabin t舱0 When the difference between them is greater than the preset value and maintained for the set time, the opening of the water inlet regulating valve, the large return water regulating valve and the small return water regulating valve are forcibly controlled, and the cooling water is forced to be sprayed in to drop below 100℃, giving priority to cooling.

[0033] Compared with the prior art, this application has the following beneficial effects:

[0034] The present invention provides a method for controlling automatic water spray cooling of high-temperature exhaust gas of an engine combustion chamber tester. The method, based on the hardware of a high-pressure cooling water system, automatically controls a water inlet regulating valve and two water return regulating valves to control the cooling water sprayed into the water jacket of a test piece cabin to change a suitable flow value under different working conditions, thereby avoiding abnormal situations such as excessive water spraying leading to water accumulation and leakage in the pipeline, and excessive gas temperature damaging exhaust equipment due to too small water spraying, so as to achieve the purpose of cooling the high-temperature exhaust gas of the engine combustion chamber tester to a set value, and realize automatic execution of response actions according to the current exhaust gas temperature without special personnel monitoring, so that the exhaust temperature is effectively reduced, and the exhaust gas temperature of the high-temperature exhaust gas water spray cooling system of the existing engine combustion chamber is automatically reduced to 150°C~200°C without manual monitoring after the control method, which can ensure that it is below 300°C and effectively control the injection flow rate to ensure that it is just vaporized without water accumulation, and at the same time meet the two requirements of energy saving and consumption reduction and rapid cooling.

[0035] In addition to the above-described purposes, features and advantages, the present application also has other purposes, features and advantages. The present application will be further described in detail with reference to the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application.

[0037] Figure 1 This is a schematic diagram of the piping of the high-temperature exhaust gas water spray system of the preferred embodiment of the present application;

[0038] Figure 2 This is a control principle diagram of the high-temperature exhaust gas water spray system of the preferred embodiment of the present application;

[0039] Figure 3 It is a flow chart of a method for automatically spraying water to cool high-temperature exhaust gas in an engine combustion chamber tester according to a preferred embodiment of the present application;

[0040] Figure 4 It is the P when the large return water regulating valve is opened at 60% and the small return water regulating valve is opened from 100% to 30%. w差 Value diagram;

[0041] Figure 5 It is the P when the large return water regulating valve is opened at 40% and the small return water regulating valve is opened from 100% to 20%. w差 Value diagram;

[0042] Figure 6 This is a schematic diagram of a linear function fitted to the opening of a large return water regulating valve.

[0043] In the figure: 1. Water reservoir; 2. Manual valve; 3. Filter; 4. Overflow valve; 5. High-pressure centrifugal water pump; 6. Check valve; 7. Water inlet regulating valve; 8. Water jacket in the test specimen cabin; 9. High-pressure water spraying rod; 10. Large return water regulating valve; 11. Small return water regulating valve; 12. Water inlet solenoid valve. DETAILED DESCRIPTION

[0044] The embodiments of the present application are described in detail below in conjunction with the accompanying drawings, but the present application can be implemented in a variety of different ways defined and covered below.

[0045] like Figure 1The high-temperature exhaust gas water spraying system shown in the figure comprises a water reservoir 1, a manual valve 2, a filter 3, an overflow valve 4, a high-pressure centrifugal water pump 5, a check valve 6, a water inlet regulating valve 7, a high-pressure water spraying rod 9, a large return water regulating valve 10, and a small return water regulating valve 11, wherein: the input end of the high-pressure centrifugal water pump 5 is connected to the filter 3, the manual valve 2 and the water reservoir 1 in sequence, and the output end of the high-pressure centrifugal water pump 5 is connected to the check valve 6, the large return water regulating valve 10, the small return water regulating valve 11, the overflow valve 4 and the output end of the high-pressure centrifugal water pump 5. The input ends are connected, the output end of the overflow valve 4 is connected to the input end of the high-pressure centrifugal water pump 5, the output ends of the large return water regulating valve 10 and the small return water regulating valve 11 are connected to the water reservoir 1, and the output end of the check valve 6 is connected to the water inlet regulating valve 7 and the high-pressure water spraying rod 9 in sequence. The high-pressure water spraying rod 9 sprays water into the water jacket 8 in the test specimen cabin. The water reservoir 1 is also provided with a liquid level controller such as a float. The liquid level controller is used to control the water inlet solenoid valve 12 to maintain the water volume in the water reservoir 1 according to the water level in the water reservoir 1.

[0046] The main control functions of water spraying of each equipment in the designed pipeline are as follows:

[0047] High-pressure centrifugal water pump: non-variable frequency stable operation, providing water inlet pressure and flow rate for water spraying;

[0048] Water inlet regulating valve 7: adjust the water inlet flow;

[0049] Large return water regulating valve 10 and small return water regulating valve 11: adjust the exhaust temperature after water spraying under the premise of ensuring the adjustment of water inlet pressure ∈ (0.1-0.5) MPa.

[0050] like Figure 2 In the control schematic diagram of the high-temperature exhaust gas water spray system shown in the figure, the high-temperature exhaust gas water spray system is a subsystem (process equipment control) of the electrical remote I / O control of a combustion chamber tester, with PLC as the control core, touch screen (local) and industrial computer (remote) as the control interface, and the high-pressure centrifugal water pump, liquid level controller, water inlet regulating valve, large return water regulating valve and small return water regulating valve are controlled through analog / digital communication.

[0051] Among them, the core PLC of the control system is mainly composed of module power supply, analog input / output module, digital input / output module, remote I / 0 module, switch, etc. PLC has Ethernet communication function, ladder diagram is compiled, and remote control is performed according to actual conditions; it communicates with third-party human-machine interface software and test system industrial computer through OPC protocol, which is fast, convenient and flexible to use. At the same time, high-precision sensors and actuators are selected, and data is transmitted by analog signal solid line or Ethernet communication method, which ensures the control accuracy and reliability of the system.

[0052] Taking a combustion chamber tester as an example, its main technical indicators are as follows:

[0053] Maximum flow rate of combustion chamber inlet air: 4kg / s;

[0054] Maximum cooling capacity of combustion chamber outlet gas temperature: 2000℃;

[0055] Maximum gas pressure at combustion chamber outlet: 3.0MPa;

[0056] Maximum fuel flow rate in combustion chamber: 0.1kg / s;

[0057] The combustion chamber outlet gas temperature needs to be reduced to ≤300℃.

[0058] The working process of the above-mentioned high-temperature exhaust gas water spray system is as follows:

[0059] The high-pressure water supply enters the water reservoir 1 of a certain tester through the valve, and the water inlet solenoid valve 12 is controlled by the liquid level controller to keep the water in the water reservoir 1 sufficient. The high-pressure centrifugal water pump 5 pressurizes the water spray pipeline, so that the cooling water is sprayed into the rear-end pipeline in four ways: ① through the water inlet regulating valve 7 and the check valve 6, sprayed from the high-pressure water spray rod 9 into the water jacket 8 in the test specimen cabin; ② through the large return water regulating valve 10 to return to the water reservoir 1; ③ through the small return water regulating valve 11 to return to the water reservoir 1; ④ when the high-pressure centrifugal water pump 5 works normally and the water inlet regulating valve 7 and the two return water regulating valves are not opened, the water is returned through the overflow valve 4.

[0060] like Figure 3 As shown, the preferred embodiment of the present application provides a method for automatically spraying water to cool high-temperature exhaust gas of an engine combustion chamber tester, based on the high-temperature exhaust gas water spray system, comprising the steps of:

[0061] S1. Before turning on the automatic control function, keep the opening of the water inlet regulating valve at 0%, the opening of the large return water regulating valve and the small return water regulating valve at 100%, and then turn on the high-pressure centrifugal water pump;

[0062] S2, set the pressure difference target value P respectively w差0 and the target temperature of the specimen in the cabin T t舱0 , where the pressure difference target value P w差0 Output pressure P of the water inlet regulating valve W水 The pressure P in the test chamber s舱 Difference P w差 The target value is greater than 0;

[0063] S3. Calculate the theoretical high-pressure cooling water flow rate W based on the heat that high-pressure water needs to absorb and the heat that 1 kg of water needs to absorb when it is completely vaporized from the inlet water temperature and heated to the required temperature after cooling under the maximum pressure of the combustion chamber outlet gas. a水0 , the PID input value for adjusting the opening of the water inlet regulating valve remains unchanged;

[0064] S4. Directly based on Tt舱0 The setting value performs PID adjustment on the opening of the small return water regulating valve, so that the small return water regulating valve moves to the exhaust temperature T of the test piece. t舱 = Target value of the test piece temperature in the chamber T t舱0 ;

[0065] S5, automatically control the opening of the large return water regulating valve, so that P w差 Maintain at set value;

[0066] S6. Through corresponding adjustment methods, wait until the water inlet regulating valve, large return water regulating valve, and small return water regulating valve all enter the stage where the opening does not change or the opening change is less than the preset value, and the measured exhaust temperature T t舱 and the target temperature value T of the specimen in the cabin t舱0 When the difference between them is less than the preset value and maintained for the set time, and meets the set steady-state accuracy requirements, the high-temperature exhaust gas water spray system is judged to have reached a steady state. Finally, the large return water regulating valve, the small return water regulating valve, and the water inlet regulating valve are automatically controlled to make the high-pressure water spray rod spray water into the water jacket in the test specimen cabin to reduce the high-temperature exhaust gas to the target temperature.

[0067] The present embodiment provides a method for controlling automatic water spray cooling of high-temperature exhaust gas in an engine combustion chamber tester. The method, based on the hardware of the high-pressure cooling water system, automatically controls a water inlet regulating valve and two water return regulating valves to control the cooling water sprayed into the water jacket in the test specimen cabin to change the appropriate flow value under different working conditions, so as to avoid abnormal situations such as excessive water spraying leading to water accumulation and leakage in the pipeline, too small water spraying leading to excessive gas temperature damaging the exhaust equipment, etc., so as to achieve the purpose of cooling the high-temperature exhaust gas in the engine combustion chamber tester to the set value, and realize automatic execution of response actions according to the current exhaust gas temperature without special personnel monitoring, so that the exhaust temperature is effectively reduced, and the exhaust gas temperature of the high-temperature exhaust gas water spray cooling system of the existing engine combustion chamber is automatically reduced to 150℃~200℃ without manual monitoring after the control method, which can not only ensure that it is below 300℃, but also effectively control the injection flow rate to ensure that it is just vaporized without water accumulation, and at the same time meet the two requirements of energy saving and consumption reduction and rapid cooling.

[0068] Preferably, the step S3 specifically comprises the steps of:

[0069] S31. Calculate the heat that high pressure water needs to absorb:

[0070] Q=m a (C p1 ×T1-C p2 ×T2)

[0071] In the formula, Q is the heat absorbed by high-pressure water, that is, the heat released by high-temperature gas, m a is the mass of high temperature fuel gas, C p1 is the constant pressure specific heat of high temperature gas before cooling, C p2is the constant pressure specific heat of the high temperature gas after cooling, T1 is the initial temperature of the high temperature gas, and T2 is the temperature of the high temperature gas after cooling;

[0072] S32. Calculate the heat Q1 required to be absorbed when 1 kg of high-pressure water is completely vaporized from the inlet temperature and heated to the required temperature after cooling under the maximum gas pressure of 3 MP at the combustion chamber outlet:

[0073] Q1= h1- h2

[0074] Wherein, h1 is the enthalpy value of water vapor at the required cooling temperature when the combustion chamber outlet gas pressure is maximum; h2 is the enthalpy value of liquid water at the inlet water temperature when the combustion chamber outlet gas pressure is maximum;

[0075] S33. Combining the above formulas, we get:

[0076] Q=m a (C p1 ×T1-C p2 ×T2) = h1- h2

[0077] Thus, the theoretical high-pressure cooling water flow rate W is obtained a水0 , the PID input value for adjusting the opening of the water inlet regulating valve remains unchanged.

[0078] In this embodiment, in order to meet the requirements of energy saving and consumption reduction and rapid cooling at the same time, the above formula is used to control the cooling water sprayed into the exhaust pipe in the cabin to change the appropriate flow value under different working conditions, so as to avoid abnormal situations such as too much water spraying resulting in water accumulation and leakage in the pipeline, too little water spraying resulting in excessive gas temperature damaging the exhaust equipment, etc.

[0079] Specifically, the pressure difference target value P is set w差0 ∈(0.1~0.5)Mpa, set the target temperature value T of the test piece in the chamber t舱0 =150℃±5℃.

[0080] The design pressure of the tester pipeline is 3MPa (absolute pressure), and the pressure inside the water pipe is generally between 0.1 and 3MPa. In order to successfully spray cooling water into the pipeline in the test chamber, P W水 >P s舱 , that is, ΔP w差 >0, and taking energy saving and function into consideration, the measured pressure difference P w差 ∈(0.1-0.5)MPa is more appropriate.

[0081] The cooling water is distributed to the high-pressure water spray rod through the water spray ring and sprayed into the water jacket in the test chamber, causing the high-temperature exhaust gas to drop rapidly. If the temperature is too low, it will cause excessive condensation, water accumulation and leakage; if the temperature is still high, it will not have a cooling protection effect. It is more appropriate to be at (100-200)℃ just enough to vaporize, so the actual test chamber temperature limit is: Tt舱 =150℃±5℃.

[0082] Preferably, the theoretical high-pressure cooling water flow rate W is calculated a水0 Then, the theoretical high-pressure cooling water flow W a水0 ×1.2 is used as the PID input value for adjusting the opening of the water inlet regulating valve, thus avoiding the influence of backwater diversion.

[0083] Preferably, in step S5, if the opening of the large return water regulating valve is automatically controlled, P w差 If the flow rate and temperature meet the requirements, the small return water regulating valve is manually adjusted to close the opening to make P w差 Maintain at the set value. This embodiment allows manual / automatic control to be switched without disturbance by adding manual control in real time.

[0084] Preferably, in step S5, when controlling the opening of the large return water regulating valve, an empirical fitting curve is used to set the valve position of the large return water regulating valve so that P w差 Maintain at set value.

[0085] The main function of the large return water regulating valve is to control the pressure difference P w差 (ie: P W水 -P s舱 ) is kept at a certain positive value so that water can be sprayed into the pipeline in the cabin smoothly. Here, the valve position is given by the empirical fitting curve to ensure that P w差 ≥0.1Mpa, considering comprehensive energy saving, keep it between (0.1-0.5)Mpa.

[0086] To ensure that P is maintained under the condition of free adjustment of the opening of the small return water regulating valve 11 w差 is a positive value. It is found that when the opening of the large return water regulating valve 10 is between 40% and 60%, no matter which value the small return water regulating valve 11 is opened to between 20% and 80%, P w差 can be maintained within the range of (0.08-1.1) Mpa, ensuring that water pressure > cabin pressure, see Figure 4 (The opening of the large return water regulating valve is 60%) Figure 5 (The opening of the large return water regulating valve is 40%).

[0087] Therefore, considering energy saving, stability, and the pressure before the pump should not be too large, the large return water regulating valve 10 is set as an empirical regulating valve. As shown in Table 1, when the opening of the large return water regulating valve 10 is between 40% and 60%, the small return water regulating valve 11 is between 40% and 80%, which meets the requirements. Under this condition, the fitted linear function curve is as follows Figure 6 shown.

[0088] Table 1

[0089] Water inlet regulating valve opening Large return water regulating valve opening Small backwater regulating valve opening Pressure difference 0% 61% / 0 0% 55% 82.30% 0.1 0% 54% 55.80% 0.2 0% 47% 46.30% 0.3 0% 44% 42% 0.4 0% 41% 39.80% 0.5

[0090] The fitting empirical curve formula of the large backwater regulating valve 10 is as follows:

[0091] y =-40 x +60.

[0092] According to this formula, to set P w差 For input value x , automatically calculate the opening value of the given large return water regulating valve 10 y .

[0093] Set the pressure difference target value P w差0 When the water inlet regulating valve output pressure P W水 The pressure P in the test chamber s舱 The target value of the difference is greater than 0 and water resources are saved. In order to effectively maintain the conditions and improve efficiency, P is directly set w差0 Between (0.1-0.5)Mpa.

[0094] Priority is given to feedforward setting to assist manual adjustment. The control system performs real-time feedforward setting about 2s in advance through the above fitting experience curve formula. During the entire adjustment process, P w差 If none of them can effectively exceed 0.1Mpa, it is preferred to manually close the opening value of the large return water regulating valve 10 (<40% and >20%) to ensure the water pipe pressure value.

[0095] The large backwater regulating valve 10 does not directly participate in T t舱 The main function of the regulation is to ensure the water pipe pressure (pressure difference). If the temperature setting value T t舱0 If a change occurs, the opening value of the large return water regulating valve 10 is not considered or considered last, but the PID self-regulation is performed by adjusting the opening of the small return water regulating valve 11. In other words, the main function of the small return water regulating valve 11 is to control the final target: the exhaust temperature T of the test piece t舱 The size of the chamber temperature is kept at (150±5)℃, while minimizing the amount of interference, avoiding chain reactions, and reducing the control burden. Under constant flow and constant pressure, when the set chamber temperature target value T t舱0 The higher the value, the less water spray is needed, and the larger the opening of the small return water regulating valve 11 is. When the target value of the test piece temperature in the cabin is set, T t舱0 The lower it is, the greater the required water spray volume is, and the smaller the opening of the small return water regulating valve 11 is.

[0096] Preferably, the engine combustion chamber tester high temperature exhaust gas automatic water spray cooling control method further comprises the steps of:

[0097] S7, when the target temperature of the test piece in the chamber is set to T t舱0 If a change occurs, the control process of steps S3 to S6 is repeated, and water is sprayed into the water jacket in the test chamber to reduce the high-temperature exhaust gas to the target temperature.

[0098] In this embodiment, when the target temperature of the test piece in the chamber is set to T t舱0 When a change occurs, it means that the temperature of the specimen in the cabin has different target requirements. In this case, only the target value T of the temperature of the specimen in the cabin needs to be changed. t舱0 , and repeat the control process of steps S3 to S6, and then spray water into the water jacket in the test chamber to reduce the high-temperature exhaust gas to the target temperature, which greatly improves the adaptability and flexibility of the control method of the present application and meets the needs of different cooling conditions.

[0099] Preferably, the engine combustion chamber tester high temperature exhaust gas automatic water spray cooling control method further comprises the steps of:

[0100] S8. If the measured exhaust temperature of the test piece is T t舱 and the target temperature value T of the specimen in the cabin t舱0 When the difference between them is greater than the preset value and maintained for the set time, the opening of the water inlet regulating valve is forced to be controlled to 60%, the opening of the large return water regulating valve is 40%, and the opening of the small return water regulating valve is 40%. The cooling water is forcibly sprayed in to drop below 100℃, with cooling as priority, or the operator can switch to manual adjustment as needed.

[0101] In this embodiment, when the normal control process described above cannot make the measured test piece exhaust temperature T t舱 When the expected control temperature is reached, this embodiment, from the perspective of safety first, forcibly controls the opening of the water inlet regulating valve to 60%, the opening of the large return water regulating valve to 40%, and the opening of the small return water regulating valve to 40%. The cooling water is forcibly sprayed to below 100°C to prevent direct damage to the test equipment and improve the safety of equipment operation.

[0102] The above embodiment finally sprays high-pressure water into the test chamber through the automatic control of three valves to reduce the high-temperature exhaust gas to (150±5)℃. When combined with the combustion chamber high-pressure bench component test, P w差 , the measured output flow rate W of the water inlet regulating valve a水 As shown in Table 2, it indicates that the limit results and control accuracy meet the requirements.

[0103] Table 2 High voltage regulation test data

[0104] <![CDATA[Exhaust P s舱 / Mpa]]> <![CDATA[T t舱 / ℃]]> <![CDATA[T t舱0 / ℃]]> <![CDATA[W a气 / kg / s]]> <![CDATA[W a水 kg / s]]> <![CDATA[W a水0 / kg / s]]> <![CDATA[P w差 / MPa]]> <![CDATA[P w差0 / MPa]]> <![CDATA[P w水 / MPa]]> 0.4 800 150 0.6 0.23 0.21 0.1 0.1 0.3 0.8 900 150 0.9 0.40 0.38 0.15 0.2 0.65 1.2 1000 150 1.2 0.60 0.52 0.18 0.2 1.02 1.5 1100 150 1.4 0.78 0.73 0.2 0.2 1.3 2 1400 150 1.8 1.32 1.35 0.25 0.3 1.75 2.5 1200 150 2.5 1.54 1.60 0.32 0.3 2.18

[0105] Although the preferred embodiments of the present application have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0106] Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A method for automatically spraying water to cool high-temperature exhaust gas in an engine combustion chamber tester, based on a high-temperature exhaust gas spray system, which includes a water reservoir, a manual valve, a filter, a high-pressure centrifugal water pump, a check valve, a water inlet regulating valve, a high-pressure water spray rod, a large return water regulating valve, a small return water regulating valve, and a relief valve, wherein: The input end of the high-pressure centrifugal water pump is connected to the filter, the manual valve and the water reservoir in sequence, the output end of the high-pressure centrifugal water pump is connected to the check valve, the large return water regulating valve, the small return water regulating valve, and the input end of the overflow valve respectively, the output end of the overflow valve is connected to the input end of the high-pressure centrifugal water pump, the output ends of the large return water regulating valve and the small return water regulating valve are connected to the water reservoir, the output end of the check valve is connected to the water inlet regulating valve and the high-pressure water spraying rod in sequence, the high-pressure water spraying rod sprays water into the water jacket in the test specimen cabin, and is characterized in that it includes the steps of: S1. Before turning on the automatic control function, keep the opening of the water inlet regulating valve at 0%, the opening of the large return water regulating valve and the small return water regulating valve at 100%, and then turn on the high-pressure centrifugal water pump; S2. Set the pressure difference target value P respectively w差0 and the target temperature of the specimen in the cabin T t舱0 , where the pressure difference target value P w差0 Output pressure P of the water inlet regulating valve W水 The pressure P in the test chamber s舱 Difference P w差 The target value is greater than 0; S3. Calculate the theoretical high-pressure cooling water flow rate W based on the heat that high-pressure water needs to absorb and the heat that 1 kg of water needs to absorb when it is completely vaporized from the inlet water temperature and heated to the required temperature after cooling under the maximum pressure of the combustion chamber outlet gas. a水0 , the PID input value for adjusting the opening of the water inlet regulating valve remains unchanged; S4. Directly based on T t舱0 The setting value performs PID adjustment on the opening of the small return water regulating valve, so that the small return water regulating valve moves to the exhaust temperature T of the test piece. t舱 = Target value of the test piece temperature in the chamber T t舱0 ; S5, automatically control the opening of the large return water regulating valve, so that P w差 Maintain at set value; S6. Through corresponding adjustment methods, wait until the water inlet regulating valve, large return water regulating valve, and small return water regulating valve all enter the stage where the opening does not change or the opening change is less than the preset value, and the measured exhaust temperature T t舱 and the target temperature value T of the specimen in the cabin t舱0 When the difference between them is less than the preset value and maintained for the set time, and meets the set steady-state accuracy requirements, the high-temperature exhaust gas water spray system is judged to have reached a steady state. Finally, the large return water regulating valve, the small return water regulating valve, and the water inlet regulating valve are automatically controlled to make the high-pressure water spray rod spray water into the water jacket in the test specimen cabin to reduce the high-temperature exhaust gas to the target temperature.

2. The automatic water spray cooling control method for high temperature exhaust gas of an engine combustion chamber tester according to claim 1, characterized in that: In step S2, the pressure difference target value P is set. w差0 ∈(0.1~0.5)Mpa, set the target temperature value T of the test piece in the cabin t舱0 =150℃±5℃.

3. The automatic water spray cooling control method for high temperature exhaust gas of an engine combustion chamber tester according to claim 1, characterized in that: The step S3 specifically comprises the following steps: Calculate the heat that high pressure water needs to absorb: Q=m a (C p1 ×T1- C p2 ×T2) In the formula, Q is the heat absorbed by high-pressure water, that is, the heat released by high-temperature gas, m a is the mass of high temperature fuel gas, C p1 is the constant pressure specific heat of high temperature gas before cooling, C p2 is the constant pressure specific heat of the high temperature gas after cooling, T1 is the initial temperature of the high temperature gas, and T2 is the temperature of the high temperature gas after cooling; Calculate the heat Q1 that needs to be absorbed when 1 kg of high-pressure water is completely vaporized from the inlet temperature and heated to the required temperature after cooling under the maximum pressure of the combustion chamber outlet gas: Q1= h1- h2 Wherein, h1 is the enthalpy value of water vapor at the required cooling temperature when the combustion chamber outlet gas pressure is maximum; h2 is the enthalpy value of liquid water at the inlet water temperature when the combustion chamber outlet gas pressure is maximum; Combining the above formulas, we get: Q=m a (C p1 ×T1- C p2 ×T2)= h1- h2 Thus, the theoretical high-pressure cooling water flow rate W is obtained a水0 , the PID input value for adjusting the opening of the water inlet regulating valve remains unchanged to control the output flow of the water inlet regulating valve.

4. The automatic water spray cooling control method for high temperature exhaust gas of an engine combustion chamber tester according to claim 3 is characterized in that: Calculate the theoretical high-pressure cooling water flow rate W a水0 Then, the theoretical high-pressure cooling water flow W a水0 ×1.2 as the PID input value for adjusting the opening of the water inlet regulating valve remains unchanged.

5. The automatic water spray cooling control method for high temperature exhaust gas of an engine combustion chamber tester according to claim 1, characterized in that: In step S5, if the opening of the large return water regulating valve is automatically controlled, P w差 If the flow rate and temperature meet the requirements, the small return water regulating valve is manually adjusted to close the opening to make P w差 Maintain at set value.

6. The automatic water spray cooling control method for high temperature exhaust gas of an engine combustion chamber tester according to claim 1, characterized in that: In step S5, when controlling the opening of the large return water regulating valve, the valve position of the large return water regulating valve is given by adopting the empirical fitting curve, so that P w差 Maintain at set value.

7. The automatic water spray cooling control method for high temperature exhaust gas of an engine combustion chamber tester according to claim 1, characterized in that: In step S6, the set steady-state accuracy is ±0.5%.

8. The method for controlling the automatic water spray cooling of high temperature exhaust gas of an engine combustion chamber tester according to claim 5, characterized in that: The water reservoir is also provided with a liquid level controller, which is used to control the water inlet solenoid valve according to the water level in the water reservoir to maintain the water volume in the water reservoir.

9. The automatic water spray cooling control method for high temperature exhaust gas of an engine combustion chamber tester according to claim 1, characterized in that: Also includes the steps: S7, when the target temperature of the test piece in the chamber is set to T t舱0 If a change occurs, the control process of steps S3 to S6 is repeated, and water is sprayed into the water jacket in the test chamber to reduce the high-temperature exhaust gas to the target temperature.

10. The automatic water spray cooling control method for high temperature exhaust gas of an engine combustion chamber tester according to any one of claims 1 to 9, characterized in that: Also includes the steps: S8. If the measured exhaust temperature of the test piece is T t舱 and the target temperature value T of the specimen in the cabin t舱0 When the difference between them is greater than the preset value and maintained for the set time, the opening of the water inlet regulating valve, the large return water regulating valve and the small return water regulating valve are forcibly controlled, and the cooling water is forced to be sprayed in to drop below 100℃, giving priority to cooling.

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