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A new technique for measuring ignition quality of diesel fuels has been evaluated. Primarily a constant volume combustion apparatus, the Diesel Fuel Ignition Analyser (DFIA) provides a direct output of ignition delay. Microprocessor control and semi-automatic operation ensure rapid determinations. Tests were performed to find the operating conditions giving the best results in terms of various performance indicators, settling upon 450°C/20bar for combustion air preheat and pressure. A preliminary correlation model based on ignition delay predicted D613 Cetane Number with ± 1.3CN at 95% confidence. More results are required to improve this correlation and define statistical precision of the method.

The results for the light duty and heavy duty diesel studies in the EPEFE have been compared, and areas of similarity and differences explored. Consistent with the intent to choose the widest possible range of engine technologies and vehicle configurations, the impact of the vehicle and engine sets on emissions was larger than that of the matrix of fuel properties. Vehicles showed a wide range in response to the fuel properties investigated. In some cases, the effects of fuel changes on emissions from the LD vehicle and HD engine sets were similar, but in other cases emissions changed in opposite directions in the two sets for the same fuel change. However, fuel changes that were beneficial for PM in LD vehicles were also positive for NOx and PM in HD engines. Differences between engine design features and test cycles were examined to investigate the reasons for these results. Fuel effects were generally larger in percentage terms for Light Duty Vehicles than for Heavy Duty Engines.