Injector Nozzle Coking With Oxygenated Diesel

The use of substances other than petroleum based fuels for power sources is not a new concept. Prior to the advent of petroleum fueled vehicles numerous other substances were used to create mobile sources of power. As the world's petroleum supply dwindles, alternative fuel sources are sought after to replace petroleum fuels. Many industries are particularly interested in the development of renewable fuel sources, or biologically derived fuel sources, which includes ethanol.

The use of No. 2 diesel as well as many alternative fuels in compression ignition engines result in injector coking. Injector coking can severely limit engine performance by limiting the amount of fuel delivered to the combustion chamber and altering the spray pattern. Injector tip coking is also one of the most sensitive measures of diesel fuel quality [1].

A machine vision system was implemented to quantify injector coking accumulation when a compression ignition engine was fueled with oxydiesel. The results show a decrease in injector coking over 200 hours of engine operation when fueled with oxydiesel compared to the coking found after a 20 hour degreening period with No. 2 diesel.