Design And Experimental Study On Intelligent Control Devices Of Cooling System In Construction Machinery

In order to solve the over-heat problem of the engine and inadequate cooling of the oil radiator as well as too much consumption of energy etc, we designed the electro-hydraulic mix-drive cooling control system, which divide traditional cooling system into two independent system, the engine cooling system and the oil cooling system. The engine cooling system was driven by hydraulic-oil, while the oil cooling system was driven by electric motor, both of the two cooling system were controlled by a single-chip according to the temperature signal which was detected by sensors. This new cooling system can cooling oil and engine separately, thus overcome many shortages exist in traditional cooling system, at the same time shortened the axial-distance when preparing the installation of the fan and improved its volumetric efficiency, lowed energy consumption of the engine, most importantly it solved the over-heat problem of the engine cooling system and the oil cooling system efficiently.The fan and pump of the engine cooling system using hydraulic motor as the original force, the flow-rate of which was controlled by electro-magnetic proportional over-flow valve, the single-chip can regulate the current value according to the coolant temperature and the target temperature, then the flow-rate of the hydraulic oil was controlled, finally the speed of the fan and the pump was controlled automatically. The fan of the oil cooling system was driven by a direct-current motor, the speed of the motor can be regulated by the single-chip which according to the temperature signal of the oil taken by oil sensor and the target temperature, at last the system can modulate the speed of the oil cooling fan automatically.The engine and oil cooling control system mainly using fuzzy control theory, in that it no need to find the specific mathematic mode of the control object, according to the control decision table which was organized by people, then from the table the system can decide the value of the control parameters. This research mainly include the following parts: the over-all design of this cooling control system, hardware design and choosing of the control system, software design and tests of this control system. Hardware design of this control system lies in the interface circuit design, while software design mainly include: main control mode design, interruption processing design, filter design, temperature sampling mode design and alarming mode design, etc.Test results show that this cooling system control device not only can solve the over heat problem of the construction machinery, but also has many other advantages, such as flexible installation, fuel saving, low nosing, small volumetric, and low power consumption, etc. This kind of cooling system suit the development of modern engine cooling system, after using this kind of control system in construction machinery largely, we will profit more from this device socially and economically.