Identification and Optimisation of Power consumed by Engine Cooling fan with viscous clutch drive in a Commercial Truck 2019-01-0146
In the present scenario detailed work is happening in the field of auxiliary power loss reduction to increase the total power output from an engine. One of the main contributors is the Engine Cooling system Fan which requires drive from engine Crank shaft to reject the heat in radiator and Charge air cooler. Auxiliary loss reduction due to this can be achieved by proper thermal management of Engine Cooling system to increase energy efficiency. The power consumed by engine Cooling fan in a vehicle during its run is difficult to measure. It is nearly 7 - 9% for a 180hp diesel engine in Commercial truck application. This loss can be reduced if we rightly balance the subsystems of engine cooling and reduce the fan duty. Now most of the Commerical vehicle engine cooling system fan drives are change from fixed to viscous clutch. Further scope is identified in optimizing the viscous fan clutch if its characteristics changes from ON-OFF to modulating.
A testing methodology is defined to measure the Fan power on engine dynamometer and further to arrive the total power consumed by fan in a typical vehicle duty cycle. This is defines as percentage of Engine brake power. The total specific fuel consumed in the engine cylinder to drive the fan is arrived. Further optimization of fan speed, behavior of viscous fan clutch and thermostat setting is done to reduce the fuel consumed to drive fan and arrive at an efficient cooling package.