Ignition and Combustion Variances of Jet Propellant-8 and Diesel Fuel in Military Diesel Engines

摘要

Currently, the U.S. Army can not purchase commercial off the shelf (COTS) on-road diesel engines for tactical wheeled vehicles due to a variety of reasons related to Environmental Protection Agency (EPA) emission regulations. Such reasons include Jet Propellant-8 (JP-8) incompatibility issues with exhaust after treatment devices and cooled exhaust gas recirculation (EGR) systems, unstable combustion regimes at part-load operation while operating on widely varying cetane number fuels such as JP-8, thermal management load increases that impact vehicle mobility and survivability, and high pressure fuel system reliability issues associated with using low lubricity fuels such as JP-8. This submission will briefly discuss these practical engine system issues and then present recent applied research that has focused on quantifying ignition and combustion differences between representative JP-8 and DF-2 samples in direct and indirect injected diesel engines through single and multicylinder experimentation, constant volume bomb experiments, spray and liquid length evaporation modeling, and shock tube experiments. The ultimate goal of this effort is to aid military engine suppliers in either converting current COTS engines to operate on JP-8 or in developing the next generation of military engines that must operate on JP-8. Such research is strictly applicable to the Army and other service agencies since military engine suppliers are currently focused on meeting future EPA emission standards which must operate on commercial ultra low sulfur diesel fuel.