Technical Paper
Diesel Fuel Effects on Emissions: Towards a Better Understanding
1998-10-19
982486
The diesel combustion process involves complex physical and chemical processes. Given this complexity it is not surprising that a wide range of fuel effects on emissions are reported in the literature. In the European Auto/Oil study the EPEFE programme showed that interactions between fuel and engine hardware could partially explain the observed emissions effects. Variations in fuel physical properties can lead to variations in injection timing, fuel delivery, exhaust gas recirculation (EGR) and other parameters. To understand fuel effects on emissions it is clear that we need to separate these different mechanisms. In this programme a modem, electronically controlled, direct-injection (DI) passenger car engine has been studied using a sophisticated test bed system which makes it possible to monitor and control all key engine variables. Seven fuels were tested, including four varying in density and poly-aromatics content taken from the EPEFE programme.