Multec 3.5 Fuel Injector Application Manual Fundamentals
Delphi Energy and Chassis Systems
Revision: 11/05-1 2-11
content of the fuel (see Table 2-1.) This must be considered in the flow
sizing of the injector and fuel supply system, as a given application will
have slightly higher fuel consumption depending on the percentage of
oxygenate in the fuel.
Ref. Sec. 2.2.7.2 & 8.4.1
In addition, small additions of these oxygenated fuels can greatly increase
the volatility of the fuel. Since this may require the fuel system
calibration to be adjusted to accommodate these types of fuels, vehicle
development testing at both hot and cold temperature extremes with these
fuels is recommended.
In general, increasing oxygenate concentrations tend to increase
deterioration of plastics and swell in elastomers. Because oxygenates
increase the solubility of water in the fuel, use of these types of fuels can
accelerate wear and corrosion in fuel system components.
For high ethanol concentration fuels, deviations from regulated or typical
levels of pHe and corrosives could compromise fuel injector performance.
Note:
Delphi tests most fuel system components to be robust to typically
available U.S. oxygenated fuel blends (maximum 2.7 mass% oxygen,
which is roughly 15% MTBE or 10% denatured ethanol). Higher
ercentages of alcohols will shorten the operating life of the injector.
Please consult a Delphi representative to obtain a current list of all fuels
the Multec 3.5 Fuel Injector has been validated in.
Specific injector models are available from Delphi with enhancements to
operate with higher oxygenated blends.
2.2.6.3 Gasoline Composition
The following provides an overview of how other constituents in gasoline
can impact both performance and emissions.
2.2.6.3.1 Paraffins (approx. 54 %mass)
As paraffin concentration increases:
• Soot formation reduced
• Resistance to surface ignition increased
• Reduced heating value (thus lower energy content and increased fuel
consumption)
• Effects octane rating
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