Fuel Dependent Heat Release Differences between Euro Diesel Fuel and RME in a HSDI Diesel Engine

In the degree that costs and demand of crude oil rise, diminish the economical disadvantages for alternative Diesel fuels, resulting in a variety of feasible substitutes. Diesel fuel substitutes have deviating exhaust emissions from conventional fuel. The methyl ester of rapeseed oil (known as RME/Biodiesel) is receiving increasing attention as an alternative fuel for Diesel engines. RME is a non-toxic, biodegradable, and renewable fuel with the potential to reduce engine exhaust emissions [1]. The main disadvantage for RME is its vaporisation and self ignition characteristics at low load conditions.
Engine experiments were carried out at 4 bar IMEP with Euro Diesel fuel (EDF) as reference and RME. During these engine experiments EGR and injection pressure were varied. As a result, differences in exhaust emissions due to EGR, injection pressure and fuel type were observed.
The objective of this work was to find answers for fuel dependent differences in indicated load and exhaust gas emissions. As combustion and emission formation of RME has not been fundamentally explained yet [2], a detailed analysis approach based on explanation models for fuel characteristics was chosen to explain the observed differences.