Process for Study of Micro-pilot Diesel-NG Dual Fuel Combustion in a Constant Volume Combustion Vessel Utilizing the Premixed Pre-burn Procedure 2019-01-1160
A constant volume spray and combustion vessel utilizing the pre-burn mixture procedure to generate pressure, temperature, and composition characteristic of near TDC conditions in compression ignition engines was modified with post pre-burn gas induction to incorporate a premixed methane gas prior to diesel injection to simulate processes in dual fuel engines. Two variants of the methane induction system were developed and studied. The first used a high-flow modified direct injection injector and the second utilized auxiliary ports in the vessel that are used for normal intake and exhaust events. Flow, mixing and limitations of the induction systems were studied. As a result of this study the high-flow modified direct injection injector was selected because of its controlled actuation and rapid closure.
Further studies of the induction system limits post pre-burn were conducted to determine the pressure and temperature limits of the methane autoignition. It was found that for sufficient induction and mixing time determined from experimental observations and CFD modeling studies, a maximum temperature -at the time of diesel pilot injection of 750K can be achieved. Although lower than TDC temperatures in diesel CI engines, this temperature is sufficient for studying dual fuel injection and autoignition with high cetane fuels. Subsequent studies of diesel pilot injection with and without post-burn methane injection were conducted and ignition delays and combustion rates were determined. Results from this work provide the basis for CFD validation and simulations of dual-fuel combustion and development of a 1D dual fuel combustion model for engine simulation.
Xuebin Yang, Vinicius Bonfochi Vinhaes, Marco Turcios, Gordon McTaggart-Cowan, Jian Huang, Jeffrey Naber, Mahdi Shahbakhti, Henry Schmidt, William Atkinson