RME Behaviour in Current and Future Diesel Fuel FIE's

The addition of a proportion of Fatty Acid Methyl Esters (FAME) in automotive diesel fuel is becoming prevalent in different areas of the world. Indeed, in several countries it is now a legislative requirement that a proportion of diesel fuel must be derived from natural sources. This trend is increasing continuously, both in terms of geographical coverage and for the use of higher percentages of bio-derived fuel.

Our work has focused mostly on Rapeseed Methyl Ester (RME). A variety of diesel fuels containing different ratios of RME has been tested to assess their propensity to form injector deposits in engines using different fuel injection systems:

• Swirl chamber (for indirect fuel injection)
• Current common rail
• Future common rail

Results have been obtained using industry recognised tests and a new test that uses future fuel injection system design.

The results indicate that RME can generate higher levels of deposits in the swirl chamber system, RME10 increases flow loss by around 10%. Future Euro V type common rail injection systems show substantial deposit formation that can generate power loss as high as around 20%. The work carried out has also highlighted problems with increased test variability associated with the use of these types of bio-components.