Theoretical and experimental study of compression ignition engine vibration and noise

الملخص EN

This paper presents an analytical model of the pressure force and vibratory response of the cylinder induced by the piston movement of compression ignition engine.

In this method, the equation of motion for the coupled system of piston and cylinder is derived, taking account of three–degree of freedom system of the piston to simulate accurately time of the pressure force and vibratory response.

The characteristics under different engine torque conditions of acoustic emission and vibration signals of the compression ignition engine from a baseline test are presented in this work.

The purpose of this research is to investigate relation the engine vibration and noise with engine performance parameters (indicated specific fuel consumption, indicated power, indicated pressure and indicated thermal efficiency), and the effect of different pressure forces on vibrations in a small diesel engine.

The investigated parameters are indicated engine performance parameters, sound pressure level (SPL) and vibration generated from engine are calculated using cylinder pressure measurements.

A MATLAB program is developed to get the pressure forces and vibration amplitudes in the three–dimensions.

It was found that the peak amplitude of acoustic emission root mean square (RMS) signals correlating to the impact like combustion related events decreased in general as the engine torque increases.

It is also noticed that the peak amplitude of the acoustic emission RMS attributing to indicated specific fuel consumption increases as the engine torque decreases.

The calculation performance of the combined system is 76.72 % when tested on the validation (theoretical) set and 75.47 % on the final test set.

The calculated results by MATLAB program show that the pressure forces and the piston vibration amplitudes agree well with measured results with relative true error of 3 %.