Prediction of Diesel Engine Exhaust Valve and Fuel Injector Faults based on Exhaust Gas Pressure Measurement and Numerical Simulation

摘要

Recently the requirements for emission reduction and fuel economy improvements have increased significantly because of environmental protection concerns. One of the best ways to ensure an engine meets these higher requirements is to monitor the combustion process and hence to maximise the optimal performance throughout its service life. In this work, an exhaust gas pressure based analysis was developed for monitoring of different engine faults. A quasi-dimensional model was developed to simulate a 4- stroke direct injection diesel engine. The model includes the prediction of incidence of various faults in a combustion system. The valve clearance was altered and a faulty injector added to a Ford FSD 425 direct injection engine which was subsequently modelled mathematically. Results have shown that the simulated exhaust pressure behaviours and measured exhaust pressure waveforms are in good qualitative agreement and hence enable the waveforms to be used for the accurate diagnosis of the different fault sources from the complicated combustion system.