Research & Realization Of Adjustable Temperature Cooling System In Construction Vehicle With Double Closed Loop Control Based On Hydraulic Driving

The research of construction vehicle cooling system has been one of the main topics in both foreign and domestic vehicle studies. The main function of the system is to keep the normal temperature of engine system, steering system, braking system, hydraulic system, to make the driver feel more comfortable, and to make use of the necessity thermal energy, etc. In order to resolve the problem of over-hot on vehicle s engine and hydraulic system, it is necessary to research and build up a test system, which can accomplish the function of research and test on the vehicle thermal management system. The test system will improve the ability and degree of our country in the vehicle cooling system, and make for the need of developing vehicle s manufacturing technology, so it is very practicality.This dissertation designs double closed loop control in vehicle s cooling system based on hydraulic driving to control the temperature of water, oil which is used in hydraulic driving and oil which is used in torque converter in the exit of radiator, and then to keep the temperature of engine and hydraulic system in its normal temperature, which can reduce the energy-consumption when the vehicle works.Vehicle's engine provides the driving force of vehicle s cooling system, we want to analyze the status of vehicle s engine when it works in differ rotate speed, so simulate its status. Using the technique of frequency conversion in three-phase motor, it is convenient to simulate vehicle s engine in differ rotate speed.The double closed loop control in vehicle s cooling system is constitute by the outer loop, temperature closed loop control, and the inside loop, fan s rotate speed closed loop control. It controls the mechanics, electro-hydraulic proportional directional valve, the flux of hydraulic motor, then adjusts the rotate speed of cooling fan, alters the cooling ability of radiator, this will makes the temperature of water, oil in the exit of radiator keeping in the normal temperature scope, and then engine, hydraulic system work in it s perfect condition.In order to analyze the system stability, the mathematical model is built up, which contains the closed loop control in motor rotate speed and in the double closed...