Engineering machinery engine cooling system
Engine cooling is essential for construction machinery, which allows the engine to be cooled appropriately and keeps it working in the most suitable temperature range. Poor operation of the cooling system is a malfunction of the engine. When the cooling is excessive, too much heat is lost, which increases fuel consumption. The fuel condensed on the cylinder wall flows into the crankcase to dilute the lubricating oil, and wear is aggravated. When the cooling is insufficient, the engine will overheat, the amount of charge will be reduced, and the combustion will be abnormal, the engine power will be reduced, and the lubrication will be poor, which will increase wear. Therefore, the cooling system is very important for construction machinery.
1. Cooling method
The cooling system of the engine has two forms of air cooling and liquid cooling. At present, the cooling of construction machinery engines uses liquid cooling technology, that is, the liquid used for cooling passes through the circulation system, and then the radiator heats the engine to cool the engine. The cooling fan It is used to compulsorily supply air to the radiator through the wind speed to meet the needs of moderate cooling of the engine. The water cooling system of construction machinery engines mainly includes water pumps, radiators, fans, water jackets, thermostats, shutters, water pipes and water temperature meters.
2. Working form of cooling fan
From the perspective of the working form of the cooling fan, there are three control methods for the cooling fan: one is the common mechanical drive control method in the current construction machinery; the other is the self-control electric control method that has nothing to do with the engine ECU and the environmental parameters are independently monitored; three It is a comprehensive intelligent control method that integrates multiple parameter information such as engine, air conditioner, compressor, and vehicle speed. The former mainly uses the principle of mechanical transmission, or is directly driven by the engine crankshaft, or the cooling fan is driven by the engine belt. Various fan control types and control technologies have their own characteristics. Each manufacturer chooses what it needs according to different situations. Therefore, various types of control technologies coexist at present. Mechanical drive is the mainstream, and automatic control and intelligent control are the trends.
3. Ventilation or blowing
But no matter which control method is adopted, the design of the engine radiator is suction type. Its design principle is to inhale the supercooling water tank from the white leaf window and then cool the engine, but it has nothing to do with the engine. The purpose is to dissipate heat (heat dissipation is to reduce the temperature), of course, to extract the air around the heat source. This is different from the concept of a human blowing fan, which is the evaporation of human sweat to take away heat. All places where there is no water are exhausted. For example: computer power supply fan, air compressor fan, air conditioning fan. Standing in front of the air conditioner, it is obvious that it is the wind blown by the fan, and there is nothing blocking it, indicating that the wind is not blowing against the radiator, but sucking.
The problem of thermal balance has always been the key to the diesel engine system. A correct understanding of the cooling system of the antifreeze system, avoiding incorrect operations in mechanical modification and maintenance, and avoiding the engine from being too "cold" or "hot" will affect the economy and power of the engine. , Work reliability has a profound impact.