Analysis of the noise emissions of a common-rail pump before and after an endurance test

Abstract

Abstract One of the problems of the modern era that we are facing nowadays, besides the pollution caused by fuel burning, is the level of noise pollution in constant growth in agglomerated cities. The main source of noise is the transport sector where the number of passenger cars had dramatically increased in recent years. Most of the vehicles around the world are powered by internal combustion engines equipped with a fuel injection system and a small percentage with an electric one. Researchers have shown that noise pollution affects human health from a psychological and physical point of view. Due to the manufacturing process of high-pressure pumps, some pumps mounted on the engine and running under certain conditions can produce a higher audible noise than the engine. The paper presents an experimental investigation on a high-pressure pump that provides a comparison between the noise level at the beginning of its lifetime and that resulting after an endurance test performed on a special test bench. It has been found that the greatest contributor to noise emissions is the high-pressure pump outlet valve when it opens. To improve the sound quality of the high-pressure pump, it is essential to further develop the outlet valve design and better control over the manufacturing process.