An experimental and computational investigation on the pre-heating of fuel to improve cold starting of diesel engines
This paper describes the effect of elevated fuel temperature on cold starting operability in compression ignition engines. This study was based on the hypothesis that in a cold start condition, fuel heated to a temperature higher than the surrounding ambient air before it enters the combustion chamber would improve cold starting. Experiments on heating the injector and the fuel before the injection event were performed in a cold room facility with ambient temperatures varying from -20 degrees to 20 degrees Celsius. A computational analysis of the injector was conducted using Star-CD to more fully understand the physical phenomena involved and help explain results obtained from the experiment. Results indicated that fuel heating does affect the efflux velocity, Sauter mean diameter and the lifetime of a fuel droplet. Droplet break-up time and spray penetration are not much affected. Computational and experimental results were within 30% of each other. Results of this work should be useful in the design of improved cold starting methods of diesel fueled engines.