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As efficient and low-pollution alternative fuel, dimethyl ether (DME) has shown its excellent performance of combustion and emissions. There is a phenomenon of DME gasification in the in-line fuel pump of DME-diesel engine. DME gasification can result in “vapor lock” and serious inequality of the fuel supply in DME-diesel fuel system. This paper presents a simple solution to improve DME gasification in DME-diesel fuel system. The key feature of the solution is just a bypass check valve, which is assembled between the intake fuel supply and the plunger chamber of the in-line pump. DME gasification in the in-line pump can be effectively eliminated by means of the bypass valve design.

This article presents a set of formulas for estimating the impact of reformed ethanol fuel on volumetric efficiency in I.C. engines. Both partial and complete usages of reformed ethanol fuel are discussed. Analysis suggests that volumetric efficiency drastically decreases as the level of fuel reforming increases in S.I. engines. Such impact on volumetric efficiency is reduced when the reformed fuel is partially used in diesel engines. A formula for calculating the impact of intake air temperature variation on volumetric efficiency is also presented. This formula is validated against engine simulation on factors such as engine load, speed, displacement, intake air temperature and reformed fuel temperature. Validation results show a maximum of 0.5% error, indicating an accurate approximation and hence high feasibility of this formula.