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Construction machinery technology adapted to plateau desert environment

Guide: Feng Huisheng, deputy director of Xining Institute of plateau construction machinery, construction machinery adapted to plateau environment (1) power recovery supercharging technology ordinary supercharged diesel engines are used in plateau areas, the power and economic indicators will still decline, and the supercharger speed will increase and match

(1) power recovery supercharging technology

ordinary supercharged diesel engines are used in plateau areas, and the power and economy index

will still decline, resulting in problems such as the increase of supercharger speed, the right shift of matching surge line,

the left shift of blocking area, the narrowing of flow range, and the reduction of compressor working range

A large number of tests have proved that the sharp increase of thermal load and the serious overspeed of supercharger are the most important factors affecting the reliability of supercharged diesel engine

plateau power recovery supercharging is mainly to take supercharging measures for non supercharged diesel engines when the plateau work

rate decreases. Within a set altitude,

make the diesel engine power, economic indicators and heat load indicators return to the original low altitude level. It increases the charge density of the cylinder through pressurized air supply, so as to improve the excess

air coefficient, so as to achieve the purpose of full combustion of fuel in the cylinder, recovery of average effective pressure and recovery of

complex power. In addition to giving the common working point sufficient margin for maximum efficiency and rated constant speed during matching, there are also corresponding requirements for turbocharger performance and structure. Reducing the heat load of diesel engine is the main auxiliary means

(2) intercooler and its application Jinan testing machine factory how to adjust the error

after the air is compressed, the temperature and pressure will increase at the same time. When the boost pressure ratio is 2

, the inflation temperature will reach more than 120 ℃, which will greatly increase the thermal load of the diesel engine

the device that cools the pressurized air before entering the cylinder is called intercooler

after the supercharged diesel engine adopts intercooling, the charging temperature decreases and the density increases, which can greatly increase the power of the diesel engine and improve the economy and heat load. The maximum combustion temperature

degree, cycle average temperature, exhaust temperature and cylinder head temperature will all decrease significantly. For this reason, intercooling technology is one of the effective and economic measures to improve diesel engine power, reduce fuel consumption and improve thermal load

(3) heat balance technology

to solve the plateau cooling problem of hydraulic system, it should be comprehensively considered together with diesel engine power recovery. It is necessary to control not only the increase of the heat load caused by the supercharging of the diesel engine, but also the temperature rise caused by the decline of the heat dissipation capacity of the transmission heat dissipation system on the plateau. When calculating the heat balance of the

system, the following factors are generally considered: cooling air volume,

air weight (the altitude can protect the sensor to a certain extent), ambient temperature, the heat dissipation capacity of the radiator, the rotation speed of the fan As an important material in the household appliance industry, the geometric parameters of the fan, the average temperature difference of the heat exchange medium, and the

heat transfer coefficient related to the material

the heat balance and heat dissipation of hydraulic transmission system shall be considered respectively according to different models

(4) Plateau low-temperature starting

due to the influence of Plateau on three aspects of low-temperature starting (in fact, it is the influence of four factors, namely, air pressure, air temperature, battery capacity, starting load), and the blocking effect of turbocharger of plateau supercharged diesel engine on engine starting intake, the low-temperature starting conditions of Plateau

supercharged construction machinery are relatively harsh. At present, there are many kinds of low-temperature measures,

, but they are rarely used in plateau areas. Therefore, more efforts should be made to solve the problem of low-temperature starting performance of construction machinery and equipment at Plateau

(5) air filtration

represents that the three characteristics of the air filter affect each other. When a certain index is

improved, other indexes will be constrained. Therefore, it is difficult to design a special series of products of

air filter suitable for plateau environment, so that it has all kinds of excellent

performances such as high efficiency, low resistance, large flow rate, long service life, small volume, light weight, low cost, easy maintenance, etc. Only the main aspects can be taken into consideration in design and research, so as to achieve relatively high performance

(6) Plateau engineering construction machinery materials and their selection

for the construction machinery used in severe cold areas, reasonably select the low temperature resistant materials in the design, and adopt the correct structural form and its welding, heat treatment process, etc.

is important for eliminating the internal stress of structural parts, making the metal structure uniform, improving the impact toughness of metal materials, and reducing the cold brittleness of materials

for the structural members of construction machinery, such as the working arm, bucket handle, bucket, bucket teeth, frame, etc., the metal materials used should not only meet the strength requirements, but also consider the impact toughness and brittle fracture rate at low temperature

the seal is easy to age in case of low temperature; Rubber pipe fittings are prone to cracking and aging under ultraviolet radiation at high altitude; Fatigue and easy to burst under the condition of low pressure at high altitude. Therefore, its durability should be considered

in addition, the rational use of oil products in plateau environment is the main link to solve the mechanical performance. General requirements: ① the transmission oil should have high flash point, low solidifying point, small change in viscosity temperature

and be resistant to oxygen, corrosion, rust and foam; ② The viscosity temperature performance of lubricating oil is stable to ensure good lubrication performance under low temperature conditions and high oil film strength under high temperature conditions; ③ For high-pressure supercharged construction machinery, due to the high thermal load, large mechanical load and harsh working conditions of the diesel engine, the lubricating oil used is required to have good low-temperature dispersion performance in addition to the above characteristics

special requirements of desert environment for engineering construction machinery

and engineering vehicles

the requirements of desert environment for engineering machinery include the following aspects:

(1) desert engineering machinery should have the characteristics of high power, flexible turning and good climbing performance. The frame should have suspension floating performance, and the machinery should also have the ability to Wade and

surpass the swamp

(2) the soft desert ground requires that the traveling devices of construction machinery vehicles have

sufficient adhesion. The advanced technology adopts tubeless compound radial tire,

and is equipped with automatic inflation and deflation device. The inflation and deflation are controlled by the sensor. The specific pressure of tire grounding will change with the driving resistance on the road. The driver monitors the tire pressure through the instrument

(3) the sandy desert environment often blocks the air filter of the engine, which is very easy to cause the wear and cylinder pulling of the engine cylinder, and it is also the main factor affecting the service life of the engine. Therefore, it is necessary to consider the use of multi-stage filtration and new structural method

(4) it is necessary to ensure that the engine has a reliable cooling system to overcome the radiation high temperature of more than 60 ℃ 1 meter away from the ground. In order to save water, it is necessary to adopt the closed

that is, the medium-sized machine may have to wait more than 30 minutes for the circulating cooling system, and improve its heat dissipation capacity to an appropriate level

(5) it is an essential and important safety measure to equip a radio communication system with reliable performance, so as to rescue when it is submerged by the desert in an unexpected storm. It is required that the power and antenna of the communication equipment should meet the requirements of the contact distance with the base

(6) install the hydraulic winch, and its drag force should meet the requirements of the machinery itself or the total weight of the loaded vehicle to drag on the dune terrain, so that mutual rescue or self rescue can be carried out between the vehicles in an unexpected environment

(7) the mobility of working vehicles in the desert is very strong. The severe desert winter that lasts for several months requires engineering machinery to have excellent low-temperature starting performance. Generally, it is required to have the ability to start reliably at -40 ℃

(8) under the operating conditions of great temperature difference in winter and summer, the cab must be equipped with

air conditioners and maintain good sealing performance. The cab must be equipped with necessary living equipment, such as double-layer sleeping bunks, workbenches, tape recorders, and water and food storage cabinets that can store food for a week

(9) crawler type construction machinery must be equipped with fully sealed lubrication crawler and overhead drive

driving wheel. Under the condition of surface temperature of about 70 ℃, the grease fitting filling method cannot guarantee the lubrication conditions. The overhead drive wheel can take measures locally when the machine cannot walk due to failure and needs to be towed, so that the crawler will not be stuck by the transmission system

(10) once the machinery breaks down in the desert, the cost is quite expensive

, and even cause the machine to be destroyed and people to die. The reliability of machine parts, electrical circuits and equipment must be improved as much as possible, and the complete construction machinery with high reliability index must be selected for desert adaptability transformation to minimize the mechanical failure rate

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