Fuel Effects on Diesel Emissions - A New Understanding 2001-01-3522

The factors governing fuel effects on diesel emissions are complex. Previous studies have demonstrated that interactions between fuel physical properties and the engine control system can result in engine calibration changes (primarily injection timing and EGR) despite the use of sophisticated electronic controls. In standard production engines, fuel effects on emissions can be strongly influenced by these interactions, making it impossible to determine the effects of fuel changes on the in-cylinder mixing and combustion processes. This paper describes fuel effects on engine-out emissions from a European light-duty diesel engine. The calibration effects were eliminated using a sophisticated test bed control system to maintain timing and EGR rate accurately at the design settings. By these means, fuel effects on the in-cylinder process could be accurately determined.