Importance of fuel injection system for low emissions, combustion noise and low fuel consumption

Due to increasingly stringent global regulations on engine and noise emissions, the fuel injection system plays a key role in reaching the stricter limits. The performance, low level of emissions and noise of a diesel engine is directly influenced by the fuel injection system which the main purpose is to deliver fuel at high pressure into engine's cylinders. Another aspect of a diesel engine is that it generates much more noise compared to a gasoline one. For this problem, the appropriate fuel injection system, such as a common-rail system, has made it possible to reduce combustion noise. The strategy consists in the use of a split injection into the combustion chamber by splitting the main injection. The purpose of this paper is to emphasize the difference between servo-controlled electrohydraulic injectors and direct acting (piezoelectric) injectors of the common-rail injection system and to explain how they can support the engine in achieving stricter emissions and noise regulations.