Combustion noise radiation during the acceleration of a turbocharged diesel engine operating with biodiesel or n-butanol diesel fuel blends

Abstract

In the current study, experimental tests were conducted on a turbocharged truck diesel engine in order to investigate the mechanism of combustion noise radiation during various accelerations and for various fuel blends. With this aim, a fully instrumented test bed was set up in order to capture the development of key engine and turbocharger parameters. Apart from the baseline diesel fuel, the engine was operated with a blend of diesel with either 30 vol % biodiesel or 25 vol % n-butanol. Analytical diagrams are provided to explain the behaviour of combustion noise radiation in conjunction with the cylinder pressure, the pressure rise rates, the frequency spectrum and the turbocharger and governor–fuel pump responses. The blend of diesel fuel with n-butanol exhibited the highest noise emissions throughout each of the transient tests examined, with differences up to 4 dBA from those with neat diesel operation. On the other hand, the biodiesel blend was found to behave marginally noisier than neat diesel oil but without a clear trend established throughout the transient events.