Reduction of Diesel Knock Noise by Controlling Piston Vibration Characteristics

Abstract

It has been required recently that diesel engines for passenger cars should meet various requirements, such as low noise, low fuel consumption, low exhaust gas emission and high power. The key to improve the noise is to reduce a combustion noise known as diesel knock noise. An experiment of the noise transfer path from a piston through a connecting rod and a crankshaft to an engine during engine operation revealed that piston resonance was a noise source. To absorb piston resonant energies, new piston structure with Natural Sound Smoother which resonates in the opposite phase to the piston is designed.