Prediction Of Combustion Noise Of Diesel Engine

The combustion noise control is an important aspect of internal combustion engine noise control. The 4102BG diesel engine manufactured by the Chaoyang diesel engine plant is selected as the research object, the prediction and control of the combustion noise has been studied in detail.The paper established the 4102BG diesel engine work process simulation model with GT-POWER software. Then built the finite element model of engine block using ANSYS software, and discussed the problems on model simplifications and element selections.The model is built using shell elements and solid elements without small orbicular cornua and small convexities. The finite element mode analysis and experimental mode analysis are done the accordingly to understand the block structure dynamic characteristics and to confirm the reliability of the finite element model. The block distortion process in one cyclic is studied by transient dynamic analysis under the cylinder pressure and the crank main bearing. Based on transient analysis, the paper studies the block surface transient sound field using the infinite element method with the SYSNOISE software, simultaneously changes the diesel engine operating modes to carry on the contrast analysis on combustion noise in the different rotational speeds and under the different crank angles at start of injection. It is found that the combustion noise is loudered as the rotational speed is higher. The combustion noise is the lowest when crank angles at start of injection is a certain angle. Finally it is found that the result accords with combustion noise change rules.