A vehicle diesel engine cooling device for high temperature environments

Abstract

The utility model relates to diesel engine technical field especially discloses a vehicle diesel engine cooling device for high temperature environment, and high and low temperature environment cabin inner surface is fixedly connected with test bench, and the diesel engine body is arranged on the upper end of test bench, and the one end of high and low temperature environment cabin upper end is fixedly connected with adjustable speed fan near the diesel engine body, and the heat dissipation efficiency (such as fin radiator, fan wind speed matching) of air -cooled diesel engine body under extreme high temperature is directly evaluated through test, ensures that the cooling capacity satisfies the design requirement, verifies whether the temperature of key components such as cylinder body, cylinder cover, piston is lower than material tolerance limit, prevents the deformation or cracking caused by thermal stress, simulates high temperature scene such as desert, plateau, verifies the stability of diesel engine body under continuous high load working condition, exposes design defect in advance through test, reduces high temperature failure rate after product is put on the market, reduces after-sales maintenance service.

Description

Technical Field

[0001] This utility model relates to the field of diesel engine technology, and in particular to a vehicle diesel engine cooling device for high-temperature environments. Background Technology

[0002] An air-cooled diesel engine is a type of diesel engine that operates through internal combustion and relies on air as a cooling medium. In an air-cooled diesel engine, fuel (diesel) is burned in the cylinder to produce high-temperature, high-pressure gas, which drives the piston in a reciprocating motion. This reciprocating motion is then converted into the rotational motion of the crankshaft via the connecting rod, thus outputting power. Unlike water-cooled diesel engines, air-cooled diesel engines utilize high-speed airflow to directly blow heat away from high-temperature components such as the cylinder block and cylinder head, achieving engine cooling and maintaining its normal operating temperature.

[0003] However, when air-cooled diesel engines operate in high-temperature environments, the efficiency of the cooling system decreases, which may lead to excessively high temperatures in components (such as cylinder heads, pistons, turbochargers, etc.), causing thermal stress, lubrication failure, seal aging, or even mechanical failure. As the power of air-cooled diesel engines increases, the heat dissipation requirements are even higher. The +45℃ thermal balance test is usually conducted at an ambient temperature of 45℃ to simulate extreme high-temperature scenarios in the tropics, deserts, or summer, ensuring that the diesel engine can still operate normally in high-temperature environments. In the research of air-cooled diesel engine whole machines and components, thermal balance testing at an ambient temperature of +45℃ has become an indispensable test item. Utility Model Content

[0004] To address the shortcomings of existing technologies, this utility model provides a vehicle diesel engine cooling device for high-temperature environments. It solves the problem that when air-cooled diesel engines operate in high-temperature environments, the cooling system efficiency decreases, potentially leading to excessively high temperatures in components (such as cylinder heads, pistons, and turbochargers), causing thermal stress, lubrication failure, seal aging, and even mechanical failure. With the increasing power of air-cooled diesel engines, the heat dissipation requirements are even higher. The +45℃ thermal balance test is typically conducted at an ambient temperature of 45℃ to simulate extreme high-temperature scenarios such as tropical regions, deserts, or summer, ensuring that the diesel engine can still operate normally in high-temperature environments. Conducting thermal balance tests at an ambient temperature of +45℃ has become an indispensable technical issue in research projects on air-cooled diesel engines and their components.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A vehicle diesel engine cooling device for high-temperature environments includes a high-low temperature environment chamber. A test bench is fixedly connected to the inner surface of the high-low temperature environment chamber. A diesel engine body is disposed on the upper end of the test bench. An adjustable speed fan is fixedly connected to the upper end of the high-low temperature environment chamber near the diesel engine body. A radiator body is fixedly connected to the upper end of the test bench near the diesel engine body. The radiator body is fixedly connected to the upper end of the test bench away from the adjustable speed fan.

[0007] Preferably, a barometer is provided at the upper end of the adjustable speed fan, and infrared thermal imagers are fixedly connected to both the test bench and the outer surface of the adjustable speed fan. A group of infrared thermal imagers are respectively arranged near the diesel engine cylinder head, cylinder block, exhaust pipe, turbocharger, radiator inlet or outlet and fairing.

[0008] Preferably, the adjustable speed fan is provided with an anemometer on its outer surface, the anemometer is located at the air inlet of the adjustable speed fan, and the anemometer is a hot-wire anemometer.

[0009] Preferably, a multi-channel high-speed recorder is fixedly connected to the inner surface of the high and low temperature environment chamber.

[0010] Preferably, a high-temperature load simulator is fixedly connected to one end of the inner surface of the high and low temperature environment chamber that is close to the multi-channel high-speed recorder, and the high-temperature load simulator is an electromagnetic load cabinet.

[0011] Preferably, a wind speed control device is fixedly connected to the inner surface of the high and low temperature environment chamber.

[0012] Preferably, the high and low temperature environment chamber is equipped with a double-layer insulation structure for temperature maintenance, the double-layer insulation structure including an outer steel plate and an inner insulation cotton.

[0013] Preferably, the outer steel plate is disposed on the inner surface of the high and low temperature environment chamber, and the inner thermal insulation cotton is disposed on the inner surface of the outer steel plate.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] 1. Through experiments, directly evaluate the heat dissipation efficiency of the air-cooled diesel engine body under extreme high temperatures (such as finned radiator and fan speed matching) to ensure that the cooling capacity meets the design requirements, verify whether the temperature of key components such as cylinder block, cylinder head, and piston is lower than the material tolerance limit, prevent deformation or cracking caused by thermal stress, simulate high-temperature scenarios such as desert and plateau, and verify the stability of the diesel engine body under continuous high load conditions.

[0016] Second, by conducting tests to expose design flaws in advance, the high-temperature failure rate after the product is launched on the market can be reduced, thus reducing after-sales maintenance services. Attached Figure Description

[0017] The above description is only an overview of the technical solution of this utility model. In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, the preferred embodiments of this utility model are described in detail below with reference to the accompanying drawings.

[0018] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0019] Figure 2 This is a diagram showing the connection structure of the diesel engine body of this utility model;

[0020] Figure 3 For the present utility model Figure 2 Enlarged view of point A in the middle;

[0021] Figure 4 This is a structural diagram of the experimental process of this utility model.

[0022] Legend: 11. High and low temperature environment chamber; 12. Test bench; 13. Diesel engine body; 14. Adjustable speed fan; 15. Radiator body; 16. Barometer; 17. Infrared thermal imager; 18. Anemometer; 19. Multi-channel high-speed recorder; 21. High temperature load simulator; 22. Wind speed control device; 23. Outer steel plate; 24. Inner insulation cotton. Detailed Implementation

[0023] This application provides a vehicle diesel engine cooling device for high-temperature environments, effectively solving the problem that the cooling system efficiency of air-cooled diesel engines decreases when operating in high-temperature environments, which may lead to excessively high temperatures in components (such as cylinder heads, pistons, turbochargers, etc.), causing thermal stress, lubrication failure, seal aging, or even mechanical failure. As the power of air-cooled diesel engines increases, the heat dissipation requirements are even higher. The +45°C thermal balance test is usually conducted at an ambient temperature of 45°C to simulate extreme high-temperature scenarios such as tropical, desert, or summer, ensuring that the diesel engine can still operate normally in high-temperature environments. In the research of air-cooled diesel engine whole and component, thermal balance testing at an ambient temperature of +45°C has become an indispensable test item. The test directly evaluates the heat dissipation efficiency of the air-cooled diesel engine body under extreme high temperatures (such as finned radiator and fan speed matching), ensuring that the cooling capacity meets the design requirements, verifying whether the temperature of key components such as cylinder block, cylinder head, and piston is below the material tolerance limit, preventing deformation or cracking caused by thermal stress, simulating high-temperature scenarios such as deserts and plateaus, and verifying the stability of the diesel engine body under continuous high-load conditions.

[0024] Example

[0025] like Figure 1 , Figure 2 , Figure 3 and Figure 4As shown, the technical solution in this application embodiment effectively solves the problem that when an air-cooled diesel engine operates in a high-temperature environment, the cooling system efficiency decreases, which may lead to excessively high temperatures in components (such as cylinder heads, pistons, turbochargers, etc.), causing thermal stress, lubrication failure, seal aging, or even mechanical failure. With the increase in power of air-cooled diesel engines, the heat dissipation requirements are even higher. The +45℃ thermal balance test is usually conducted at an ambient temperature of 45℃ to simulate extreme high-temperature scenarios in the tropics, deserts, or summer, ensuring that the diesel engine can still operate normally in high-temperature environments. This is part of the research project on the air-cooled diesel engine as a whole and its components. Conducting thermal equilibrium tests at an ambient temperature of +45℃ is an indispensable technical challenge. The overall approach is as follows: A vehicle diesel engine cooling device for high-temperature environments includes a high-low temperature environment chamber 11. A test bench 12 is fixedly connected to the inner surface of the high-low temperature environment chamber 11. A diesel engine body 13 is mounted on the upper end of the test bench 12. An adjustable-speed fan 14 is fixedly connected to the upper end of the high-low temperature environment chamber 11 near the diesel engine body 13. A radiator body 15 is fixedly connected to the upper end of the test bench 12 near the diesel engine body 13. The radiator body 15 is fixed... A barometer 16 is installed on the upper end of the test bench 12, away from the adjustable speed fan 14. Infrared thermal imagers 17 are fixedly connected to the outer surfaces of both the test bench 12 and the adjustable speed fan 14. A set of infrared thermal imagers 17 are positioned near the diesel engine cylinder head, cylinder block, exhaust pipe, turbocharger, radiator inlet or outlet, and fairing. An anemometer 18 is installed on the outer surface of the adjustable speed fan 14, located at the air inlet of the fan. The anemometer 18 is a hot-wire anemometer. High and low temperature environmental chamber 11: temperature range -40°C. Temperature range: ℃~+150℃, control accuracy: ±0.5℃, built-in adjustable speed fan 14 (simulating natural wind or forced air cooling), wind speed control system is used to control the air output efficiency of adjustable speed fan 14: supports wind speed adjustment from 0.5 to 10 m / s, covering air flow adjustment at different altitudes or installation scenarios, infrared thermal imager 17, arranged in key areas such as cylinder head, cylinder block, exhaust pipe, turbocharger, radiator body 15 inlet or outlet, and deflector, gas temperature measuring point, which must be resistant to high temperature (≥800℃), anemometer 18 (hot wire anemometer), barometer 16 (monitoring the pressure difference before and after testing).

[0026] A multi-channel high-speed recorder 19 is fixedly connected to the inner surface of the high and low temperature environment chamber 11. A high-temperature load simulator 21 is fixedly connected to one end of the inner surface of the high and low temperature environment chamber 11 near the multi-channel high-speed recorder 19. The high-temperature load simulator 21 is an electromagnetic load cabinet. The multi-channel high-speed recorder 19 (sampling frequency ≥100Hz) synchronously records parameters such as temperature, wind speed, pressure, and vibration. An adjustable speed fan / blower (simulates different wind speed conditions) is also included. The high-temperature load simulator 21 (such as an electromagnetic load cabinet) and an infrared thermal imager 17 (real-time monitoring of surface temperature field distribution) are also included.

[0027] A wind speed control device 22 is fixedly connected to the inner surface of the high and low temperature environment chamber 11. The high and low temperature environment chamber 11 is equipped with a double-layer insulation structure for temperature maintenance. The double-layer insulation structure includes an outer steel plate 23 and an inner heat insulation cotton 24. The outer steel plate 23 is placed on the inner surface of the high and low temperature environment chamber 11, and the inner heat insulation cotton 24 is placed on the inner surface of the outer steel plate 23. The test chamber must be sealed and equipped with a double-layer insulation structure (outer steel plate 23 + inner heat insulation cotton 24). The test bench 12 must be insulated from the ground to avoid vibration interference with sensor signals.

[0028] To address the problems existing in the prior art, this utility model provides a vehicle diesel engine cooling device for high-temperature environments. It directly evaluates the heat dissipation efficiency of the air-cooled diesel engine body 13 under extreme high temperatures (such as the matching of finned radiators and fan speed) through experiments, ensuring that the cooling capacity meets the design requirements. It verifies whether the temperature of key components such as the cylinder block, cylinder head, and piston is lower than the material tolerance limit, preventing deformation or cracking caused by thermal stress. It also simulates high-temperature scenarios such as deserts and plateaus to verify the stability of the diesel engine body 13 under continuous high-load conditions.

[0029] High and low temperature environment chamber 11: Provides a space to simulate different temperature environments, with a temperature range of -40℃ to +150℃ and a control accuracy of ±0.5℃; its interior is equipped with a double-layer insulation structure (outer steel plate 23 and inner insulation cotton 24). The test chamber must be sealed to maintain a stable test temperature environment and reduce interference from the external environment to the test; at the same time, it has a built-in adjustable speed fan 14, which can simulate natural wind or forced air cooling. The wind speed control system can control the air output efficiency of the adjustable speed fan 14, supporting wind speed adjustment from 0.5 to 10 m / s to cover the air flow adjustment needs of different altitudes or installation scenarios. Together with the adjustable speed fan 14, it simulates different air cooling conditions for the diesel engine body 13 under test.

[0030] Test bench 12: Set inside the high and low temperature environment chamber 11, it is used to support the diesel engine body 13 and keep it in a stable test position; and the test bench 12 must be insulated from the ground to avoid vibration interference with sensor signals, ensure that the data collected by the sensors during the test is accurate and reliable, and work with other components to provide stable support and environmental protection for the test of the diesel engine body 13.

[0031] Diesel engine body 13: As a test object, its operation in a high-temperature environment is simulated in this device. Its heat dissipation efficiency, key component temperature, stability under continuous high load conditions and other performance indicators are evaluated through various tests to verify whether it meets the design requirements, expose design defects in advance, and reduce the high-temperature failure rate after the product is launched to the market.

[0032] Adjustable speed fan 14: Installed at the upper end of the high and low temperature environment chamber 11 near the diesel engine body 13, under the action of the wind speed control system of the high and low temperature environment chamber 11, the wind speed can be adjusted from 0.5 to 10 m / s to simulate natural wind or forced air cooling conditions, and provide cooling airflow of different wind speeds to the diesel engine body 13. Together with the high and low temperature environment chamber 11, it simulates the air cooling environment under different altitudes or installation scenarios, and evaluates the performance of the diesel engine body 13 under different air cooling conditions.

[0033] Radiator body 15: Fixed to the upper end of the test bench 12 away from the adjustable speed fan 14, and cooperates with the diesel engine body 13 to assist the diesel engine body 13 in heat dissipation; during the test, its surface is cleaned to ensure that there is no dust or foreign matter blocking it, so as to ensure its heat dissipation performance is good, and together with other components, the heat dissipation efficiency of the air-cooled diesel engine body 13 under extreme high temperature is evaluated, such as the matching of finned radiator and fan speed.

[0034] Barometer 16: Located at the upper end of the adjustable speed fan 14, it is used to monitor the pressure difference before and after the test, and to provide data support for analyzing the impact of changes in air volume and wind speed on the cooling effect of the diesel engine during the test. In conjunction with components such as anemometer 18 and multi-channel high-speed recorder 19, it comprehensively records the environmental parameters during the test.

[0035] Infrared thermal imager 17: A group of infrared thermal imagers 17 are respectively arranged near the diesel engine cylinder head, cylinder block, exhaust pipe, turbocharger, radiator inlet or outlet and fairing, etc., to monitor the surface temperature field distribution of these key areas in real time. By recording temperature data, it helps to evaluate the temperature status of each component of the diesel engine body 13 during the test, and verify whether the temperature of key components such as cylinder block, cylinder head, piston and so on is lower than the material tolerance limit, so as to prevent deformation or cracking caused by thermal stress. In conjunction with the multi-channel high-speed recorder 19, it records temperature data synchronously, providing a basis for analyzing diesel engine performance.

[0036] Anemometer 18: A hot-wire anemometer is set at the air inlet of the adjustable speed fan 14 to measure the wind speed at the air inlet of the adjustable speed fan 14, providing real-time wind speed data for the wind speed control system so as to accurately control the air output efficiency of the adjustable speed fan 14. Together with barometer 16, multi-channel high-speed recorder 19, etc., it records environmental parameters during the test process and helps to evaluate the cooling effect of the diesel engine under different wind speed conditions.

[0037] Multi-channel high-speed recorder 19: Fixed on the inner surface of the high and low temperature environment chamber 11, with a sampling frequency ≥100Hz, it can simultaneously record parameters such as temperature, wind speed, pressure, and vibration; it integrates and records temperature data monitored by infrared thermal imager 17, wind speed data measured by anemometer 18, differential pressure data monitored by barometer 16, and vibration data collected by other relevant sensors, providing detailed data support for comprehensive analysis of the performance of diesel engine body 13 during the test process;

[0038] High-temperature load simulator 21: It adopts an electromagnetic load cabinet, which is fixed on the inner surface of the high and low temperature environment chamber 11 near one end of the multi-channel high-speed recorder 19. It is used to simulate the load of the diesel engine body 13 in actual operation, and gradually increases to 100% of the rated power (such as 25%, 50%, 75%, 100%). Each stage is run stably for 30 minutes. It is used in conjunction with the diesel engine body 13 to conduct steady-state thermal balance tests, etc., to evaluate the performance of the diesel engine under different loads. It is used in conjunction with the multi-channel high-speed recorder 19 to record relevant parameters and assist in the analysis of diesel engine performance.

[0039] Wind speed control device 22: Fixed on the inner surface of the high and low temperature environment chamber 11, working in conjunction with the wind speed control system of the high and low temperature environment chamber 11, precisely controlling the operation of the adjustable speed fan 14 according to the set wind speed requirements, realizing the adjustment of wind speed from 0.5 to 10 m / s, simulating different wind speed air-cooling environments for the diesel engine body 13, so as to evaluate its cooling performance under different air-cooling conditions.

[0040] Outer steel plate 23: As the outer layer of the double-layer insulation structure of the high and low temperature environment chamber 11, it is set on the inner surface of the high and low temperature environment chamber 11. Together with the inner insulation cotton 24, it forms an insulation structure, enhances the insulation performance of the high and low temperature environment chamber 11, reduces heat loss or external heat transfer, ensures the temperature inside the high and low temperature environment chamber 11 is stable, and provides a stable temperature environment for testing.

[0041] Inner layer insulation cotton 24: It is set on the inner surface of the outer steel plate 23 and together with the outer steel plate 23, it forms a double-layer insulation structure of the high and low temperature environment chamber 11. It effectively prevents heat transfer, improves the insulation effect of the high and low temperature environment chamber 11, and keeps the temperature inside the chamber within the set range, ensuring the stability of the test environment and facilitating accurate evaluation of the performance of the diesel engine body 13 under different temperature environments.

[0042] Working principle:

[0043] First, before conducting the operating environment test on the diesel engine block 13, clean the surface of the radiator block 15 to ensure it is free of dust or foreign matter. Replace it with high-temperature resistant lubricating oil (such as SAE 5W-40 fully synthetic oil). Place and install infrared thermal imagers 17 at the diesel engine cylinder head, turbocharger outlet, and exhaust pipe outlet. When conducting the operating environment test on the diesel engine block 13, first start the diesel engine block 13 under no-load cold break-in (0-30 min) and run it at low speed (500-800 rpm) under no-load conditions, gradually increasing it to (1500-2000 rpm). The key monitoring points are: lubricating oil pressure and cylinder temperature. Second, conduct a steady-state thermal balance test (1-2 h) with graded load loading: gradually increase to 100% of rated power (such as 25%, 50%, 75%, 100%), and run stably for 30 min at each stage. Data acquisition frequency: record key parameters (temperature, pressure) every 10 seconds. The criteria for judging the qualified results of the experiment are: oil temperature ≤120℃, cylinder head temperature ≤220℃, transient working condition simulation of rapid load switching: from 50% load to 100% load, observe the temperature response time (recovery stability ≤2min), extreme heat dissipation failure test: manually turn off the fan or block part of the heat sink, trigger protection (such as power reduction or shutdown), and directly evaluate the heat dissipation efficiency of the air-cooled diesel engine body 13 under extreme high temperature (such as finned heat sink, fan speed matching) through the test to ensure that the cooling capacity meets the design requirements, verify whether the temperature of key components such as cylinder block, cylinder head, piston and so on is lower than the material tolerance limit, prevent deformation or cracking caused by thermal stress, simulate high temperature scenarios such as desert and plateau, verify the stability of the diesel engine body 13 under continuous high load conditions through the test, expose design defects in advance through the test, reduce the high temperature failure rate after the product is launched to the market, and reduce after-sales maintenance services.

[0044] The second step involves a high and low temperature environment chamber 11: temperature range -40℃ to +150℃, control accuracy ±0.5℃, and a built-in adjustable speed fan 14 (simulating natural wind or forced air cooling). A wind speed control system is used to control the airflow efficiency of the adjustable speed fan 14, supporting wind speed adjustment from 0.5 to 10 m / s, covering airflow adjustment at different altitudes or installation scenarios. An infrared thermal imager 17 is placed in key areas such as the cylinder head, cylinder block, exhaust pipe, turbocharger, radiator body 15 inlet or outlet, and fairing. It serves as a gas temperature measuring point and must be heat resistant (≥800℃). The equipment includes a tachometer 18 (hot-wire anemometer), a barometer 16 (monitoring pressure difference before and after testing), a multi-channel high-speed recorder 19 (sampling frequency ≥100Hz) to simultaneously record parameters such as temperature, wind speed, pressure, and vibration, an adjustable speed fan / blower (simulating different wind speed conditions), a high-temperature load simulator 21 (such as an electromagnetic load cabinet), and an infrared thermal imager 17 (real-time monitoring of surface temperature field distribution). The test chamber must be sealed and equipped with a double-layer insulation structure (outer steel plate 23 + inner insulation cotton 24). The test bench 12 must be insulated from the ground to avoid vibration interference with sensor signals.

[0045] Finally, it should be noted that the above embodiments are merely examples for clearly illustrating the present invention and are not intended to limit the implementation. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations. However, obvious variations or modifications derived therefrom are still within the protection scope of this invention.

Claims

1. A vehicle diesel engine cooling device for high-temperature environments, comprising a high-low temperature environment chamber (11), wherein a test bench (12) is fixedly connected to the inner surface of the high-low temperature environment chamber (11), characterized in that, The test bench (12) is provided with a diesel engine body (13) at the upper end. The high and low temperature environment chamber (11) is fixedly connected to an adjustable speed fan (14) at the upper end near the diesel engine body (13). The test bench (12) is fixedly connected to a radiator body (15) at the upper end near the diesel engine body (13). The radiator body (15) is fixedly connected to the upper end of the test bench (12) away from the adjustable speed fan (14).

2. The vehicle diesel engine cooling device for high-temperature environments as described in claim 1, characterized in that, A barometer (16) is provided at the upper end of the adjustable speed fan (14). In the test bench (12) and the variable speed fan (14), infrared thermal imagers (17) are fixedly connected to the outer surfaces. A group of infrared thermal imagers (17) are respectively arranged near the diesel engine cylinder head, cylinder block, exhaust pipe, turbocharger, radiator inlet or outlet and fairing.

3. A vehicle diesel engine cooling device for high-temperature environments as described in claim 2, characterized in that, An anemometer (18) is provided on the outer surface of the adjustable speed fan (14); The anemometer (18) is located at the air inlet of the adjustable speed fan (14), and the anemometer (18) is a hot wire anemometer.

4. A vehicle diesel engine cooling device for high-temperature environments as described in claim 3, characterized in that, A multi-channel high-speed recorder (19) is fixedly connected to the inner surface of the high and low temperature environment chamber (11).

5. A vehicle diesel engine cooling device for high-temperature environments as described in claim 4, characterized in that, A high-temperature load simulator (21) is fixedly connected to one end of the inner surface of the high and low temperature environment chamber (11) near the multi-channel high-speed recorder (19). The high-temperature load simulator (21) is an electromagnetic load cabinet.

6. A vehicle diesel engine cooling device for high-temperature environments as described in claim 5, characterized in that, A wind speed control device (22) is fixedly connected to the inner surface of the high and low temperature environment chamber (11).

7. A vehicle diesel engine cooling device for high-temperature environments as described in claim 6, characterized in that, The high and low temperature environment chamber (11) is equipped with a double-layer insulation structure for temperature maintenance. The double-layer insulation structure includes an outer steel plate (23) and an inner insulation cotton (24).

8. A vehicle diesel engine cooling device for high-temperature environments as described in claim 7, characterized in that, The outer steel plate (23) is installed on the inner surface of the high and low temperature environment chamber (11); The inner layer of heat insulation cotton (24) is disposed on the inner surface of the outer layer of steel plate (23).

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