On the Cooling Fan Actuator to EMS in the Vehicle

Abstract

The drive force of engine cooling fan increases in the proportion of engine size and operation velocity. It's one of the reasons of engine power consumption and is the main source of engine noise and vibration. Generally, insufficient fan revolution results in overheating and poor cooling operation. In case of engine overcooling the driving horse power decreases and results in engine noise. If a fan is kept in operation continuously, poor fuel economy, unwanted noise and battery dead will be caused. In case of cooling fan by thermostatic coil spring, even the advantages of viscous cooling fan clutch, it's impossible to control precise engine temperature and fan revolution velocity because of its only On/Off function for valve lever by bimetallic spring with two different thermal coefficients. Hence, it's imperative to apply high edge electronic systems to solve strict technology issues and it's essential to apply electronic sensor and actuator for vehicles which requires high environmental protection and reliability in harsh service areas. In this paper, the optimization of engine management system (EMS) controlled viscous cooling fan was investigated to control cooling fan drive and its velocity by direct engine temperature and engine management system according to PWM signals.