Abstract: The noise/variation generate-mechanism and its variation law changing with engine speed and load were investigated by tests to realize diesel-engine on-line fault-diagnosis, and design and optimize enginestructure. The experiments were conducted in a turbocharged inter-cooled diesel engine fueled on Fischer- Tropsch (F-T) diesel or 0# diesel, in which measured were the surface vibration signals of engine combustion. The signals were analyzed by an A-Weighted network for diesel engine fault diagnosis. The results show that the sound pressure reach the peak for the two fuels with the noises in 86.7—99 dB at the frequencies of 0.5—2.0 kHz. The vibration acceleration variation law is obtained in a whole working cycle of cylinder head. The diesel engine fueled on F-T diesel has softer combustion, slower heat release rate, slower pressure rise rate, and smaller vibration / noise compared with the 0# diesel.

Key words: diesel engines, combustion, Fischer-Tropsch (F-T) diesel, vibration, noise, on-line fault diagnosis