Technical Paper
Effects of Pilot Injection Parameters on Combustion for Common Rail Diesel Engines
2003-03-03
2003-01-0700
The aim of the present work is to evaluate the influence of the pilot injection on combustion of a TDI Diesel engine for different engine torque and speed conditions. For this investigation, pilot injection timing and duration were varied on a wide range of values, and their effects on combustion pressure, rate of heat release, pilot and main combustion delay, combustion process and exhaust emissions in terms of NOx and smoke were analyzed. An in-line, four-cylinder, turbocharged FIAT 1930 cm3 TDI Diesel engine, equipped with Common Rail injection system, was tested. A piezoelectric sensor was located in the combustion chamber in order to acquire combustion pressure; from these signals, gross heat release rate was derived in order to analyze the combustion behavior. Pollutant emission levels have been measured by means of a gas analyzer, while for smoke an opacimeter was used.