On the Potential of Oxygenated Fuels as an Additional Degree of Freedom in the Mixture Formation in Direct Injection Diesel Engines

摘要

The current and future restrictions on pollutant emissions from internal combustion engines require a holistic investigation of the abilities of alternative fuels to optimize the combustion process and ensure cleaner combustion. In this regard, the Tailor-made Fuels from Biomass (TMFB) Cluster at Rheinisch-Westfalische Technische Hochschule (RWTH) Aachen University aims at designing production processes for biofuels as well as fuels optimal for use in internal combustion engines. The TMFB Cluster's scientific approach considers the molecular structure of the fuels as an additional degree of freedom for the optimization of both the production pathways and the combustion process of such novel biofuels. Thus, the model-based specification of target parameters is of the utmost importance to improve engine combustion performance and to send feedback information to the biofuel production process. In particular, computational fluid dynamics is used to underscore the role of the thermo-physical properties on the soot emissions in internal combustion engines. Utilizing a preliminary established sensitivity analysis, it was possible to identify C8 straight chain oxygenated molecules as the optimal candidate for the inherent reduction of soot emissions within the mixture formation process. Additionally, the Oxidation Potential Number (OPN) is presented as a new indicator of the inherent soot reduction inside diesel spray plumes.