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The accepted model of conventional diesel combustion [1] assumes a rich premixed flame slightly downstream of the maximum liquid penetration. The soot generated by this rich premixed flame is burnt out by a subsequent diffusion flame at the head of the jet. Even in situations in which the centre of combustion (CA50) is phased optimally to maximize efficiency, slow late stage combustion can still have a significant detrimental impact on thermal efficiency. Data is presented on potential late-stage combustion improvers in a EURO VI compliant HD engine at a range of speed and load points. The operating conditions (e.g. injection timings, EGR levels) were based on a EURO VI calibration which targets 3 g/kWh of engine-out NOx. Rates of heat release were determined from the pressure sensor data. To investigate late stage combustion, focus was made on the position in the cycle at which 90% of the fuel had combusted (CA90). An EN590 compliant fuel was tested.

Government regulations and market demands continue to emphasize conservation of fossil fuels in the transportation industry. As a consequence, any incremental improvement in fuel economy (FE) is of great importance in the automotive sector. For instance, lower viscosity lubricants have been shown to improve FE but the longevity of such improvement is compromised by viscosity increases often observed as a lubricant ages during an oil drain interval (ODI). To address this issue, an option to manage lubricant viscometrics via fuel is proposed. In order to investigate such mitigation of viscosity increase during an ODI, and potentially the delivery of an ODI-averaged FE benefit, a fleet test was conducted with a fuel-borne additive intended to control increases in lubricant viscosity. The fleet test compared a market-representative reference fuel to a fuel containing a viscosity control additive (VCA).

The effects of various aspects of FAME quality and sources on injector nozzle fouling, when blended into diesel were investigated systematically. The B10 fuels used for this investigation are representative of available FAME qualities in the market. The variables used to assess quality were age, water content, saturation level, monoglycerides level, antioxidant content and feedstock. The B10 fuels were tested in a PSA (Peugeot Société Anonyme) DW10 bench engine operating to a modified version of the CEC (Coordinating European Council) F-98 Nozzle Coking Test. Power loss was used as the primary indicator of nozzle fouling. Power loss did not exceed 1% with any of the B10 blends tested, which is within the repeatability limits. These results show that this set of B10s, formulated with market quality and worst-case quality FAME, did not cause measurable injector nozzle fouling in this modified version of the industry standard engine test.