The Precise Control Of Engine Temperature

This is a disquisition on the study of the engine temperature precisely control. We reconstructed the cooling system of 491Q engine which is a single point injection engine,and dismissed the relation between the water pump and the cooling fan clutch; There are two 12v DC motors driving the water pump and cooling fan and controlling the rotate speed by PWM method; There is also a controllable thermostat that is designed by myself replaced the primary paraffine thermostat and a temperature sensor which is installed at the place of radiator's output water pipe. The temperature of engine output water signal,the temperature of engine input water signal,the engine speed signal and the pressure of manifold signal were send to the DAQ board in NI measurement and control system after processed .Those signals were acquired and calibrated as the input parameter of the controller. Since the precise mathematic model of engine cooling system is not established easily, I used the fuzzy control concept and realized control in the LabVIEW. The controlled objects are the water pump motor,cooling fan motor and the controllable thermostats. The engine temperature measurement and control system is a multi-input and multi-output system, the controlling target keeps the setting temperature value(engine output water temperature) in the small scope of the error(±1℃).The main content of my study is engine cooling control system that is introduced ahead. Based on this ,using eddy current dynamometer,fuel consumption instrument and exhaust analysis equipment, under the different load-conditions, try to find the optimal temperature point in the current condition depending on the power,economic performance index though the analysis of correlative data.