Influence of Injection System Parameters on Combustion Noise of a Small Power Non-Road Diesel Engine

Combustion noise accounts for a large proportion of diesel engine noise. On the premise of not increasing the cost of diesel engine, the injection system parameters such as dynamic fuel supply advance angle and needle valve opening pressure are optimized, and the influence of the above parameters on the in-cylinder pressure, rate of pressure rise, in-cylinder pressure level (CPL) spectrum and high frequency pressure oscillation is analyzed. The study shows that reducing the dynamic fuel supply advance angle can effectively reduce the combustion noise, and appropriately increasing the needle valve opening pressure can also reduce the combustion noise. After the optimization of injection parameters, the combustion noise of the diesel engine with an electronically controlled VE pump-tube-nozzle injection system is significantly reduced compared with the prototype engine, and can reach the same level of combustion noise as the diesel engine with the common rail system without deterioration of fuel economy and emission performance. The experimental study can provide technical reference for diesel engines in the selection of injection system parameters and the optimization of combustion noise in the improvement stage.