AN INVESTIGATION OF THE ROLE OF INJECTION PARAMETERS ON DIESEL ENGINE NOISE

Abstract

As awareness of noise hazard is becoming widespread, there is now a growing interest in every means of reducing the noise of existing engines and designing quieter engines for future. Little inforMation is found in the literature on the behaviour of single cylinder small stationary diesel engines which are commonly employed in the country in the agricultural sector and in standby power units in urban areas. The first chapter outlines the problem area. The second chapter reviews the history of the development of the understanding of engine noise causes, control strategies with an emphasis on the role of injection parameters on engine noise. Third chapter describes the experimental setup and measurement procedure. The results of the investigation are presented and dicussed in chapter four. Finally chapter five gives the important conclusions arrived at in the present investigation. In essence, it was found that increasing the injector spring pre-load increased fuel line pressure and reduced peak cylinder pressure. There is an optimum range of the injector spring pre-load setting for which engine radiated noise and both BSFC and exhaust smoke opacity tend to have some minimum values. Increasing injector spring pre-load, delays the dynamic injection timings commencing it closer to tdc_and--hence a reduction in ignition delay and therefor•e•-a reduction in noise, fuel consumption and smoke in high to rated engine speed, suggesting a more efficient combustion. Reducing the injector spring pre-load at low engine speed, decreases fuel injection rate and reduces noise. Increasing injector spring pre-load for rated and higher speeds also reduces duration of injection, hence noise, fuel consumption and smoke is reduced.