Tail gas emission system and emission method for simulating plateau environment

Abstract

The invention belongs to the technical field of detection equipment, and particularly discloses a tail gas emission system for simulating a plateau environment, which comprises an environment simulation cabin, and a fresh air assembly, a fan assembly, a first vacuum pump assembly and a second vacuum pump assembly which are arranged on the outer side of the environment simulation cabin, and the fresh air assembly and the second vacuum pump assembly are connected with the environment simulation cabin; the fan assembly and the first vacuum pump assembly are selectively connected with the vehicle; in the normal-pressure operation mode, the first vacuum pump assembly and the second vacuum pump assembly are closed, the fan assembly and the fresh air assembly are started, and vehicle tail gas is discharged after being mixed and cooled through the fan assembly; and during low-pressure mode operation, the fan assembly is closed, the first vacuum pump assembly, the second vacuum pump assembly and the fresh air assembly are started, and vehicle tail gas is discharged through the first vacuum pump assembly. Tail gas is exhausted in a normal-pressure mode and a low-pressure mode, and energy waste and loss of equipment are reduced. The invention further discloses an emission method using the tail gas emission system for simulating the plateau environment.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of detection equipment, and particularly relates to a tail gas emission system and method for simulating a plateau environment. BACKGROUND

[0002] The plateau region has special natural environmental conditions such as low air pressure and low oxygen, which poses a severe challenge to the performance, reliability and safety of various engines, vehicles and equipment. For example, when a car enters a plateau region, oxygen deficiency occurs, which causes incomplete combustion and affects engine power, and the control of the entire vehicle system is very challenging. Therefore, simulating a plateau climate environment in a laboratory for testing has become an indispensable key link in the vehicle research and development and quality verification process.

[0003] In the prior art, a large vacuum cabin is generally used in combination with a vacuum pump set to realize vehicle tail gas emission in a plateau environment simulation system. However, the emission system of such a simulation system is usually designed only for low-pressure mode, which has the following problems in actual operation: The workers usually need to prepare for vehicle experiments in a normal-pressure environment, including connecting various harnesses, oil pipes and starting the engine of the vehicle, and since the system design does not consider tail gas treatment under normal pressure, even a small amount of tail gas generated by the vehicle during the preparation stage must be treated by starting the vacuum pump under low pressure. The core design function of the vacuum pump is to remove gas molecules from a closed space to create a vacuum environment. However, when the vacuum pump is started under normal pressure, it needs to overcome the resistance of one atmosphere (about 100 kPa) of normal pressure to pump air, which is the most laborious working condition, resulting in energy waste and large equipment loss. SUMMARY

[0004] The purpose of the present application is to provide a tail gas emission system for simulating a plateau environment, which distinguishes between normal-pressure mode and low-pressure mode for emitting tail gas, reduces energy waste of equipment, and reduces equipment loss.

[0005] The purpose of the present application is achieved by the technical scheme, and specifically provides a tail gas emission system for simulating a plateau environment, which includes an environment simulation cabin and a fresh air assembly, a fan assembly, a first vacuum pump assembly and a second vacuum pump assembly arranged outside the environment simulation cabin, the fresh air assembly and the second vacuum pump assembly being connected with the environment simulation cabin; the fan assembly includes a fan and a blower, and the fan assembly and the first vacuum pump assembly are selectively connectable with a vehicle; in a normal-pressure operation mode, the first vacuum pump assembly and the second vacuum pump assembly are closed, the fan assembly and the fresh air assembly are started, the fresh air assembly delivers gas to the environment simulation cabin, and the vehicle tail gas is mixed with the gas delivered by the blower and then extracted by the fan after being cooled; in a low-pressure operation mode, the fan assembly is closed, the first vacuum pump assembly, the second vacuum pump assembly and the fresh air assembly are started, and the vehicle tail gas is extracted by the first vacuum pump assembly.

[0006] Preferably, the first vacuum pump assembly comprises a first heat exchanger, a first buffer tank and a first vacuum pump; one end of the first heat exchanger is connected with the vehicle, and the other end is connected with the first buffer tank, and the other end of the first buffer tank is connected with the first vacuum pump.

[0007] Preferably, the fan assembly further comprises a second heat exchanger and a second buffer tank; one end of the second heat exchanger is connected with the air supply fan, and the other end is connected with the fan through the second buffer tank.

[0008] Preferably, the first vacuum pump assembly comprises a first heat exchanger, a first buffer tank and a first vacuum pump; one end of the first heat exchanger is connected with the vehicle and the air supply fan respectively, and the other end is connected with the first buffer tank, and the other end of the first buffer tank is connected with the first vacuum pump and the fan respectively.

[0009] Preferably, a physical pressure relief device is further included and is arranged outside the cabin top of the environment simulation cabin.

[0010] Due to the adoption of the above technical scheme, the present application has the following advantages: In the plateau atmospheric environment simulation system, the vehicle exhaust is divided into normal pressure operation mode and low pressure operation mode, and the optimal exhaust treatment mode is configured for each mode, so that the first vacuum pump assembly is used to extract the exhaust under normal pressure, the fan assembly is used to extract the exhaust, and the environment air is used for mixing and cooling, thereby reducing energy waste and equipment loss.

[0011] Another object of the present application is to provide a method for simulating a plateau environment and discharging exhaust, which discharges exhaust according to normal pressure operation mode and low pressure operation mode, reduces energy waste and equipment loss of the equipment, and maintains the pressure in the environment simulation cabin.

[0012] Another object of the present application is achieved by the technical scheme, and specifically provides a method for simulating a plateau environment and discharging exhaust, which comprises the following steps: S1. Setting a target altitude value and a corresponding target pressure value; S2. Judging the target pressure value and the current environmental atmospheric pressure: if the target pressure value is greater than or equal to the current environmental atmospheric pressure, entering the normal pressure operation mode, and if the target pressure value is less than the current environmental atmospheric pressure, entering the low pressure operation mode; S3. In the normal pressure operation mode, the vehicle exhaust is discharged through the fan assembly, and the fresh air assembly is used to maintain the pressure in the environment simulation cabin at the target pressure value; or In the low pressure operation mode, the vehicle exhaust is extracted and discharged through the first vacuum pump assembly, and the fresh air assembly and the second vacuum pump assembly are used to maintain the pressure in the environment simulation cabin at the target pressure value.

[0013] Preferably, in step S3, the specific steps of the atmospheric pressure operation mode are as follows: turn off the first vacuum pump assembly and the second vacuum pump assembly, and at the same time start the fresh air assembly, control the air volume delivered by the fresh air assembly to the environmental simulation chamber to achieve and maintain the chamber pressure to the target pressure value.

[0014] Preferably, in step S3, the low-pressure operation mode specifically includes the following steps: S31. Turn off the fresh air assembly and simultaneously start the second vacuum pump assembly to evacuate the environmental simulation chamber to the target pressure value; S32. Maintain the pumping speed of the second vacuum pump assembly and stabilize the pressure of the environmental simulation chamber by controlling the amount of dry air delivered to the environmental simulation chamber by the fresh air assembly; S33. Start the vehicle engine, the vehicle exhausts the exhaust gas, and simultaneously start the first vacuum pump assembly to extract the vehicle exhaust gas to the outside of the environmental simulation chamber.

[0015] Preferably, in step S3, the system operates in atmospheric pressure mode, and the required exhaust volume of the fan assembly is M. 总 =Mx+Mw=Mw(t1-t3) / (t3-t2)+Mw, where Mx is the dilution air flow rate, Mw is the exhaust gas flow rate, t1 is the exhaust gas temperature, t2 is the ambient air temperature, and t3 is the target temperature after mixing.

[0016] Preferably, the experiment also includes the following step: after the experiment, the air pressure inside the environmental simulation chamber is restored to normal pressure.

[0017] Because of the adoption of the above technical solution, the present invention has the following advantages: The exhaust gas emission operates in two modes: normal pressure and low pressure. Through the coordinated operation of the fan assembly, fresh air assembly, first vacuum pump assembly, and second vacuum pump assembly, the exhaust gas is effectively discharged, reducing energy waste and equipment wear, and achieving and maintaining the pressure of the environmental simulation chamber. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the specific embodiments will be briefly introduced below. In all the drawings, the elements or parts are not necessarily drawn to scale.

[0019] Figure 1 This is a schematic diagram of the exhaust gas emission system for simulating a plateau environment according to the present invention; Figure 2 This is a schematic diagram of a second embodiment of the exhaust gas emission system for simulating a plateau environment according to the present invention; Figure 3 This describes the steps of a method for simulating exhaust gas emissions in a high-altitude environment.

[0020] Figure label: 1- environmental simulation cabin, 11- pressure cabin, 12- heat preservation cabin, 13- first cabin door, 14- bearing table, 15- physical pressure relief device, 16- pressure sensor; 2- fresh air assembly, 21- first air valve; 3- fan assembly, 31- fan, 32- air blower, 33- fourth air valve, 34- fifth air valve, 35- gas mixing box, 36- second buffer tank, 37- second heat exchanger, 38- first coolant storage tank; 4- first vacuum pump assembly, 41- second air valve, 42- first heat exchanger, 43- first buffer tank, 44- first vacuum pump, 45- first coolant storage tank; 5- second vacuum pump assembly, 51- second vacuum pump, 52- air pipe, 53- third air valve. DETAILED DESCRIPTION

[0021] The embodiments of the technical solutions of the present application will be described in detail below with reference to the accompanying drawings.

[0022] Please refer to Figure 1 and Figure 2 , a tail gas emission system for simulating plateau environment, comprising an environmental simulation cabin 1 and a fresh air assembly 2, a fan assembly 3, a first vacuum pump assembly 4 and a second vacuum pump assembly 5 arranged outside the environmental simulation cabin 1, the fresh air assembly 2 and the second vacuum pump assembly 5 being connected with the environmental simulation cabin 1; the fan assembly 3 comprises a fan 31 and an air blower 32, and the fan assembly 3 and the first vacuum pump assembly 4 are selectively connectable with a vehicle; in normal pressure operation mode, the first vacuum pump assembly 4 and the second vacuum pump assembly 5 are closed, the fan assembly 3 and the fresh air assembly 2 are started, the fresh air assembly 2 delivers gas to the environmental simulation cabin 1, and the vehicle tail gas is extracted after being mixed with and cooled by the gas delivered by the air blower 32 through the fan 31; in low pressure operation mode, the fan assembly 3 is closed, the first vacuum pump assembly 4, the second vacuum pump assembly 5 and the fresh air assembly 2 are started, and the vehicle tail gas is extracted by the first vacuum pump assembly 4.

[0023] Specifically, the environmental simulation cabin 1 comprises a pressure cabin 11 and a heat preservation cabin 12 arranged inside the pressure cabin 11; the pressure cabin 11 is composed of a steel framework lattice shell and is placed in the outermost layer, and the size (length x width x height) of the pressure cabin 11 is about 24500 mm x 12800 mm x 9500 mm after the assembly of the present application is completed. The size (length x width x height) of the inner cavity of the heat preservation cabin 12 is about 22000 mm x 7500 mm x 7500 mm. One side of the pressure cabin 11 is provided with a first cabin door 13 for the entry and exit of test products, the first cabin door 13 comprises an outer door and an inner door, the outer door is a single-wing electric sliding door with pressure bearing function, and the inner door is a double-wing door with heat preservation function. A bearing table 14 for test products is arranged on the inner surface of the bottom of the heat preservation cabin 12.

[0024] The tail gas emission system simulating plateau environment is provided with a central processing unit, the central processing unit is electrically connected with the fresh air assembly 2, the fan assembly 3, the first vacuum pump assembly 4 and the second vacuum pump assembly 5 and other associated components, in the application, the S7 series programmable central processing unit produced by Siemens Company is adopted as the central processing unit, and digital I / O modules and analog I / O modules are provided, the working conditions of the refrigeration, heating, exhaust, gas conveying and other subsystems are controlled through software, so that high-precision control in the whole temperature and pressure range is ensured.

[0025] The fresh air assembly 2 adopts the existing technology, for example, the air intake air conditioning unit mentioned in the authorized announcement CN110940527B, entitled "Automobile engine simulated plateau environment intake and exhaust system", the fresh air assembly 2 provides dry gas to the environment simulation cabin 1. The fresh air assembly 2 is communicated or disconnected with the environment simulation cabin 1 through the first air valve 21.

[0026] The second vacuum pump assembly 5 includes a second vacuum pump 51 and at least two air pipes 52, each air pipe 52 is communicated with different positions of the heat preservation cabin 12, at least two air pipes are arranged, the air in the heat preservation cabin 12 can be uniformly extracted, so that the preset target pressure is quickly reached, the second vacuum pump assembly 5 is communicated or disconnected with the environment simulation cabin 1 through the third air valve 53. The second vacuum pump 51 adopts the water ring vacuum pump with a model of 2BE1-303 produced by Shandong Boshan Kaiyuan Industrial Pump Manufacturing Co., Ltd., the pumping speed is 4000m³ / h, which is used for air extraction of the environment simulation cabin 1, so as to keep the pressure of the environment simulation cabin 1 stable.

[0027] The fan 31 adopts the tail gas emission fan with a model of XFB-450A / 7.5kW manufactured by Guangzhou Xinfeng Fan Co., Ltd. The fan 31 is connected with the output end of the exhaust tail gas through the fourth air valve 33, and the air supply fan 32 is connected with the output end of the exhaust tail gas through the fifth air valve 34. The gas mixing box 35 is arranged between the fan 31 and the air supply fan 32, which is used for providing a mixing and cooling space for the low-temperature air of the external environment transported by the air supply fan 32 and the high-temperature gas emitted by the vehicle, and then the mixed gas is extracted by the fan 31 and transported to the outside of the environment simulation cabin 1. The fan 31 adopts the model TB200-15 produced by Quanfeng Environmental Protection Technology Co., Ltd., and the motor power is 11kW.

[0028] The first vacuum pump assembly 4 is connected with the output end of the vehicle exhaust tail gas through the second air valve 41.

[0029] The first air valve 21, the third air valve 53, the fourth air valve 33 and the fifth air valve 34 are all DN250 regulating type air valves, which prevent the pumping speed from being too fast, and the second air valve 41 is a pressure control valve.

[0030] The central processor is electrically connected with the first air valve 21, the second air valve 41, the third air valve 53, the fourth air valve 33, the fifth air valve 34, the fresh air assembly 2, the fan assembly 3, the first vacuum pump assembly 4, the second vacuum pump assembly 5 and the like.

[0031] The exhaust emission system for simulating plateau environment of the application, when in use, the staff operates the vehicle test preparation work under normal pressure, after completion, starts the normal pressure mode operation, that is, closes the second air valve 41 and the third air valve 53, opens the first air valve 21 and the fourth air valve 33, starts the fan assembly 3, starts the vehicle engine, the vehicle exhaust high-temperature exhaust gas, the fan 31 extracts the high-temperature exhaust gas, first with the low-temperature gas delivered by the air blower 32 in the gas mixing box 35, then through the fan 31 to the environment simulation cabin 1 outside; after confirming that the vehicle can work normally, the fan assembly 3, the fourth air valve 33, the first air valve 21 and the second air valve 41 are closed, the second vacuum pump assembly 5 and the third air valve 53 are started, the environment simulation cabin 1 is pumped, until it is consistent with the preset target air pressure value, at this time, the pumping speed of the second vacuum pump 51 is kept, the fresh air assembly 2 and the first air valve 21 are started, and the pressure of the environment simulation cabin 1 is stabilized through the fresh air intake amount. The low-pressure mode operation is entered, the vehicle engine is started, the vehicle exhaust high-temperature exhaust gas, the first vacuum pump assembly 4 and the second air valve 41 are started, and the high-temperature exhaust gas is discharged outside the environment simulation cabin 1 after the first vacuum pump assembly 4, after the test, the air valves are closed, and the air pressure in the environment simulation cabin 1 is restored to normal pressure.

[0032] The plateau air pressure environment simulation system divides the vehicle exhaust into normal pressure operation mode and low pressure operation mode, and optimizes the exhaust treatment mode for each mode, which avoids the use of the first vacuum pump assembly 4 to extract the exhaust gas under normal pressure, the use of the fan assembly 3 to extract the exhaust gas, and the use of the environment air to mix and cool, which is the most economical and efficient way, reduces energy waste and equipment loss.

[0033] Example one Further, the first vacuum pump assembly 4 comprises a first heat exchanger 42, a first buffer tank 43 and a first vacuum pump 44. One end of the first heat exchanger 42 is connected with the vehicle, the other end is connected with the first buffer tank 43, and the other end of the first buffer tank 43 is connected with the first vacuum pump 44. Specifically, the first vacuum pump 44 adopts an explosion-proof vacuum pump, and a 2BE1-303 water ring vacuum pump produced by Boshan Kaiyuan Industrial Pump Manufacturing Co., Ltd. is adopted, with a suction speed of 4000m³ / h. In the present application, two or more first vacuum pumps 44 are connected in parallel. The working principle of the first vacuum pump assembly 4 is the same as that of the first vacuum system in the highland environment simulation test cabin of the internal combustion power equipment disclosed in the authorized announcement CN102866017B, and the name is the same. The first heat exchanger 42 adopts the heat exchanger disclosed in the authorized announcement CN114279253B, and the cooling liquid includes but is not limited to water. A first cooling liquid storage tank 45 is arranged on one side of the first heat exchanger 42, and the two ends of the first cooling liquid storage tank 45 are respectively communicated with the liquid inlet and the liquid outlet of the first heat exchanger 42.

[0034] Further, the fan assembly 3 further comprises a second heat exchanger 37 and a second buffer tank 36. One end of the second heat exchanger 37 is connected with the air blower 32, and the other end is connected with the fan 31 through the second buffer tank 36. Specifically, one end of the second heat exchanger 37 is communicated with the output end of the gas mixing box 35. In use, the vehicle exhaust first enters the gas mixing box 35, mixes with the low-temperature gas delivered by the air blower 32, and is cooled. The mixed gas is cooled for the second time by the second heat exchanger 37, and then is discharged by the fan 31 after being buffered by the second buffer tank 36. The second heat exchanger 37 is provided with a second cooling liquid storage tank 38. With this structure, it is helpful to reduce the temperature and pressure of the mixture and reduce the damage to the fan 31.

[0035] Please refer to Figure 2, embodiment two, the first vacuum pump assembly 4 includes a first heat exchanger 42, a first buffer tank 43 and a first vacuum pump 44; one end of the first heat exchanger 42 is connected with the vehicle and the air blower 32 respectively, the other end is connected with the first buffer tank 43, the other end of the first buffer tank 43 is connected with the first vacuum pump 44 and the fan 31 respectively. Specifically, the fan assembly 3 further includes a mixed gas heat exchanger and a mixed gas buffer tank, one end of the mixed gas heat exchanger is connected with the vehicle, the other end is connected with the mixed gas buffer tank, the other end of the mixed gas buffer tank is connected with the fan 31, preferably, in order to save cost, the fan assembly 3 and the first vacuum pump assembly 4 share a set of heat exchanger and buffer tank, one end of the first buffer tank 43 is connected with the fourth gas valve 33 and the second gas valve 41 respectively, the first heat exchanger 42 is connected with the gas mixing box 35 and the vehicle respectively. In use, when the normal pressure operation mode, the vehicle exhaust gas passes through the gas mixing box 35, the first heat exchanger 42, the first buffer tank 43 and the fourth gas valve 33 in turn, the mixed gas is discharged from the fan 31, which helps to further reduce the exhaust temperature of the mixed gas; when the normal pressure operation mode, the vehicle exhaust gas passes through the gas mixing box 35, the first heat exchanger 42, the first buffer tank 43 and the second gas valve 41 in turn, the exhaust gas is discharged from the first vacuum pump 44. With this structure, it will not affect the switching of normal pressure operation mode and low pressure operation mode.

[0036] Further, the exhaust emission system further comprises a physical pressure relief device 15 arranged outside the cabin top of the environmental simulation cabin 1. Specifically, one end of the physical pressure relief device 15 extends into the environmental simulation cabin 1 and is electrically connected with the central processor to monitor the air pressure of the environmental simulation cabin 1. When the system fails and the pressure is too low, the central processor controls the physical pressure relief device 15 to break when the cabin pressure is lower than 40Kpa, ensuring the safety of personnel and the cabin.

[0037] Further, the exhaust emission system further comprises not less than three pressure sensors 16, at least one of which is arranged outside the environmental cabin and at least two of which are arranged inside the environmental simulation cabin 1. Specifically, the pressure sensor 16 is electrically connected with the central processor, and when the data of any two pressure sensors 16 arranged inside the environmental simulation cabin 1 differ by 2KPa during real-time detection at low pressure, the central processor sends an alarm and quickly pressurizes to prevent inaccurate pressure sensors 16 from causing the pressure of the environmental simulation cabin 1 to be too low, causing damage to personnel or products.

[0038] Further, the exhaust emission system further comprises a differential pressure sensor to ensure that the pressure between the inside and outside of the cabin is slightly positive, thereby realizing automatic control and adjustment of fresh air volume, and keeping the cabin slightly positive (0Pa-100Pa) at all times under test cycle conditions.

[0039] Please refer to Figure 3A method for simulating high-altitude environment exhaust emission, comprising the following steps: S1. Setting a target altitude value and a corresponding target pressure value; S2. Determining whether the target pressure value is greater than or equal to the current ambient atmospheric pressure: if yes, entering a normal pressure operation mode, and if no, entering a low pressure operation mode; S3. In the normal pressure operation mode, the vehicle exhaust is discharged through the fan assembly 3, and the fresh air assembly 2 is used to achieve and maintain the pressure in the environment simulation cabin 1 at the target pressure value; or In the low pressure operation mode, the vehicle exhaust is extracted and discharged through the first vacuum pump assembly 4, and the fresh air assembly 2 and the second vacuum pump assembly 5 are used to achieve and maintain the pressure in the environment simulation cabin 1 at the target pressure value.

[0040] Specifically, according to the test requirements, the target pressure values of different altitudes are set, and the pressure adjustment range is normal pressure-50kpa (5500m altitude). The central processing unit monitors the cabin and cabin atmospheric pressure of the environment simulation cabin 1, and if the staff is working under normal pressure, the vehicle test preparation work is carried out, and if not, the atmospheric pressure in the environment simulation cabin 1 is adjusted to be consistent with the cabin outside by controlling the fresh air assembly 2 and the first vacuum pump assembly 4.

[0041] Further, in the S3 step, the normal pressure operation mode specific steps are as follows: the first vacuum pump and the second vacuum pump are closed, and the fresh air assembly 2 is started to control the delivery air volume of the fresh air assembly 2 to the environment simulation cabin 1 to achieve the cabin pressure reaching and maintaining to the target pressure value. Start the vehicle engine, the vehicle exhaust, the fan assembly 3 absorbs the exhaust, the fan assembly 3 introduces the ambient air to mix and dilute the exhaust, and then cools and discharges outside the environment simulation cabin 1. In this process, in order to meet the consumption of the vehicle engine to the gas in the environment simulation cabin 1, the fresh air assembly 2 inputs dry fresh air to supplement, the exhaust volume of the fresh air assembly 2 is controlled by the differential pressure sensor to realize the balance of the cabin pressure, maintain the target pressure value of the environment simulation cabin 1, the fresh air assembly 2 adopts frequency conversion control, and the maximum output of the fresh air is 3600kg / h and can be adjusted.

[0042] Further, in step S3, the low-pressure operation mode specifically includes the following steps: S31. Shut down the fresh air assembly 2 and simultaneously start the second vacuum pump assembly 5 to evacuate the environmental simulation chamber 1 to the target pressure value; S32. Maintain the pumping speed of the second vacuum pump assembly 5 and stabilize the pressure of the environmental simulation chamber 1 by controlling the amount of dry air delivered to the environmental simulation chamber 1 by the fresh air assembly 2; S33. Start the vehicle engine, the vehicle exhausts, and simultaneously start the first vacuum pump assembly 4 to extract the vehicle exhaust to the outside of the environmental simulation chamber 1. During this process, in order to meet the consumption of gas in the environmental simulation chamber 1 by the vehicle engine, the exhaust volume of the fresh air assembly 2 is controlled by a differential pressure sensor to achieve pressure balance in the chamber and maintain the target pressure value of the environmental simulation chamber 1. The fresh air assembly 2 adopts frequency conversion control, and the maximum fresh air output is 3600 kg / h and is adjustable.

[0043] Furthermore, the process includes the following steps: After the test, the air pressure inside the environmental simulation chamber 1 is restored to normal pressure. The environmental simulation chamber 1 is equipped with several air intake valves spaced circumferentially on its walls. After the test is completed, the central processing unit activates the air intake valves, allowing the environmental simulation chamber 1 to quickly regain pressure. In this application, the environmental simulation chamber 1 recovers to normal pressure in approximately 2-3 minutes. With this structure, if the engine suddenly starts and the fresh air assembly 2 or the second vacuum pump fails, causing a rapid pressure drop or falling below a safe value, the central processing unit can control the air intake valves to activate quickly, preventing excessively low pressure from causing injury to equipment or personnel.

[0044] Furthermore, in step S3, operating in normal pressure mode, the required exhaust volume of the fan assembly 3 is: M 总 =Mx + Mw = Mw(t1-t3) / (t3-t2) + Mw, where Mx is the dilution air flow rate, Mw is the exhaust gas flow rate, t1 is the exhaust gas temperature, t2 is the ambient air temperature, and t3 is the target temperature after mixing. Specifically, the exhaust gas flow rate is calculated as follows: Based on Mw=ge×Pe(K×R+1), in this application, the engine power is 400kW, the fuel is diesel, the fuel consumption rate is 0.263kg / kW.h, the air-fuel ratio is 14.5, the air coefficient is 1.972, and the calculated vehicle exhaust mass flow rate is 3114kg / h.

[0045] The required air volume for the fan assembly 3 is the amount of air to be extracted after mixing and cooling the high-temperature exhaust gas generated by the engine with ambient air in a calculated ratio, M. 总= Mx+ Mw, the mixing ratio is determined by the heat balance formula Mx x C (t3-t2) = Mw x C (t1-t3), the mass flow of the mixed air at normal temperature is calculated to be 2650 kg / h; the mass flow of the exhaust gas to be discharged at normal pressure is 3113+2650=5764 kg / h, the density of the exhaust gas at a temperature of 270°C is 0.65 kg / m3, the safety factor is 1.1, and the total exhaust volume flow required is 5764 x 1.1 / 0.65 = 9755 m3 / h.

[0046] According to the above calculation, the exhaust fan selection at normal pressure is the exhaust fan XFB-450A / 7.5kW produced by Xinfeng, with a maximum air volume of 13220 m3 / h, which meets the requirement of the maximum exhaust gas volume of 9755 m3 / h at normal temperature.

[0047] In the S3 step, when the low-pressure mode is running, according to the above exhaust gas discharge mass flow calculation, the engine with a power of 400 kW has a mass flow discharge of 3114 kg / h, and when the air pressure is low, the exhaust gas cooling is directly extracted to the environment simulation cabin 1 outside, and does not need air mixing cooling, so the mass flow of the exhaust gas is calculated to be 3114 kg / h, and the volume flow of the exhaust gas at 50KPa is calculated to be 5772 m3 / h.

[0048] High-altitude climate exhaust vacuum pump configuration: according to the above calculation of the volume flow of the high-altitude climate exhaust gas, the volume flow is 5772 m3 / h, the safety factor is taken as 1.2, 5772 x 1.2 = 6926 m3 / h, that is, the required vacuum pump pumping speed is 6926 m3 / h at 50KPa, a water ring vacuum pump is selected, two Kairun 2BE1-303 vacuum pumps are configured, and the single pumping speed is 4000 m3 / h, the total pumping speed is 8000 m3 / h, the required vacuum pump pumping speed is 6926 m3 / h, which meets the exhaust discharge requirement.

[0049]

[0050] In this application, the vacuum pump configuration in the environment simulation cabin 1: the volume of the environment simulation cabin 1 is 1578 m3, according to the calculation, it takes 20 minutes to reach 50KPa, and the pumping speed required is 3938 m3 / h, a 2BE1-303 water ring vacuum pump is configured, the pumping speed is 4000 m3 / h, which meets the demand of the environment simulation cabin 1 for air exhaust and pressure maintenance.

[0051]

[0052] From the above process, it is shown that the most economical and effective cooling method under normal pressure is to introduce ambient air for mixing and dilution, which only needs the power consumption of the fan 31 and the blower 32, and the total motor power consumption is 11+7.5=18.5kW; if the same amount of gas is extracted using the first vacuum pump assembly 4, two first vacuum pumps 44 are needed, 110x2=220kW, so the energy consumption will increase by 11 times to complete the same work, causing huge waste of electricity. And under normal pressure, the first vacuum pump 44 compresses the gas conversion heat energy, which is absorbed by the circulating water in it, which will cause the water temperature to rise sharply, resulting in large equipment loss.

[0053] The tail gas emission system and test method of the present application simulate the plateau environment, and the normal pressure tail discharge and low pressure discharge are switched according to the environmental test pressure. When the set value of the target pressure value is greater than the current atmospheric pressure, the normal pressure operation mode is adopted, and when the set value is less than the current atmospheric pressure, the low pressure operation mode is adopted. The vehicle tail gas is divided into normal pressure operation mode and low pressure operation mode, and the optimal tail gas treatment method is configured for each mode, avoiding the use of the first vacuum pump to extract the exhaust gas under normal pressure, using the fan assembly 3 to extract the exhaust gas, and mixing and cooling with ambient air, which is the most economical and efficient way, reducing energy waste and equipment loss. The fan assembly 3 and the first vacuum pump assembly 4 share a set of heat exchanger and buffer tank, saving cost.

[0054] The above specific embodiments further illustrate the purpose, technical solutions and advantages of the present application. It should be understood that the above description is only a specific implementation method of the present application and is not intended to limit the present application. Any modification, equivalent replacement and improvement within the scope of the present application should be included in the protection scope of the present application.

Claims

1. An exhaust emission system simulating a high altitude environment, characterized in that, The application relates to an environment simulation cabin (1) and a fresh air assembly (2), a fan assembly (3), a first vacuum pump assembly (4) and a second vacuum pump assembly (5) arranged outside the environment simulation cabin (1), the fresh air assembly (2) and the second vacuum pump assembly (5) are connected with the environment simulation cabin (1); the fan assembly (3) comprises a fan (31) and a blower (32), and the fan assembly (3) and the first vacuum pump assembly (4) can be selectively connected with a vehicle; In the normal pressure operation mode, the first vacuum pump assembly (4) and the second vacuum pump assembly (5) are closed, the fan assembly (3) and the fresh air assembly (2) are started, the fresh air assembly (2) transports gas to the environment simulation cabin (1), the vehicle exhaust is mixed with the gas transported by the blower (32), and the mixture is extracted through the fan (31) after being cooled; In the low pressure operation mode, the fan assembly (3) is closed, and the first vacuum pump assembly (4), the second vacuum pump assembly (5) and the fresh air assembly (2) are started, and the vehicle exhaust is extracted through the first vacuum pump assembly (4). The first vacuum pump assembly (4) comprises a first heat exchanger (42), a first buffer tank (43) and a first vacuum pump (44); one end of the first heat exchanger (42) is connected with the vehicle, the other end is connected with the first buffer tank (43), and the other end of the first buffer tank (43) is connected with the first vacuum pump (44).

2. The simulated altitude environment tailpipe exhaust system of claim 1, wherein, The fan assembly (3) further comprises a second heat exchanger (37) and a second buffer tank (36), one end of the second heat exchanger (37) is connected with the blower (32), and the other end is connected with the fan (31) through the second buffer tank (36).

3. The simulated altitude environment exhaust system of claim 1 or 2, wherein, The first vacuum pump assembly (4) comprises a first heat exchanger (42), a first buffer tank (43) and a first vacuum pump (44); one end of the first heat exchanger (42) is connected with the vehicle and the blower (32) respectively, the other end is connected with the first buffer tank (43), and the other end of the first buffer tank (43) is connected with the first vacuum pump (44) and the fan (31) respectively.

4. The simulated altitude environment tailpipe exhaust system of claim 1, wherein, The physical pressure relief device (15) is arranged outside the top of the environment simulation cabin (1).

5. The simulated altitude environment exhaust system of claim 1, 2, or 4, wherein, The application further relates to a method for controlling the environment simulation cabin (1), and the method comprises the following steps:

6. An exhaust emission method using the simulated plateau environment exhaust emission system according to any one of claims 1 to 5, characterized by, S1. setting a target altitude value and a corresponding target pressure value; S2. judging the target pressure value and the current atmospheric pressure: if the target pressure value is greater than or equal to the current atmospheric pressure, the normal pressure operation mode is entered, and if the target pressure value is less than the current atmospheric pressure, the low pressure operation mode is entered; S3. in the normal pressure operation mode, the vehicle exhaust is discharged through the fan assembly (3), and the fresh air assembly (2) is used to reach and maintain the pressure in the environment simulation cabin (1) to be the target pressure value; or In the low pressure operation mode, the vehicle exhaust is extracted and discharged through the first vacuum pump assembly (4), and the fresh air assembly (2) and the second vacuum pump assembly (5) are used to reach and maintain the pressure in the environment simulation cabin (1) to be the target pressure value. In the S3 step, the normal pressure operation mode specifically comprises the following steps: the first vacuum pump assembly (4) and the second vacuum pump assembly (5) are closed, the fresh air assembly (2) is started at the same time, the delivery air volume of the fresh air assembly (2) to the environment simulation cabin (1) is controlled, and the pressure of the environment simulation cabin (1) is reached and maintained to be the target pressure value.

7. The venting method of claim 6, wherein, ​ 8. The venting method of claim 6, wherein, In the S3 step, the low-pressure operation mode specifically includes the following steps: S31, the fresh air assembly (2) is closed, and the second vacuum pump assembly (5) is started to pump the environment simulation cabin (1) to a target pressure value; S32, the pumping speed of the second vacuum pump assembly (5) is kept, and the dry air volume delivered by the fresh air assembly (2) to the environment simulation cabin (1) is controlled to stabilize the pressure of the environment simulation cabin (1); and S33, the vehicle engine is started, the vehicle exhaust is emitted, and the first vacuum pump assembly (4) is started to pump the vehicle exhaust out of the environment simulation cabin (1).

9. The venting method according to any one of claims 6 to 8, characterized in that, In the S3 step, the normal-pressure mode is operated, and the required exhaust air volume of the fan assembly (3) is M 总 =Mx+Mw=Mw(t1-t3) / (t3-t2)+Mw, Mx is the dilution air flow rate, Mw is the exhaust gas flow rate, t1 is the exhaust gas temperature, t2 is the normal temperature air temperature, and t3 is the target temperature after mixing.

10. The venting method according to any one of claims 6 to 8, characterized in that, The method further includes the following step: after the test is completed, the air pressure in the environment simulation cabin (1) is restored to normal pressure.

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