Haibo Dong (Advisor), Hui Wan (Committee Member), Zifeng Yang (Committee Member)
Master of Science in Engineering (MSEgr)
A Gasoline Direct Injection (GDI) engine enables an increased fuel efficiency and higher power output than a conventional Port Fuel Injection (PFI) system. By injecting pressurized fuel straight into each cylinder of an internal-combustion engine, the degree of fuel atomization is increased, as well as the fuel vaporization rate. In order to further harness the effects of direct injection, ethanol is implemented as a fuel. The cooling effect of ethanol fuel droplets changing to vapor inside the combustion chamber facilitates a higher compression ratio, thus increasing engine power and efficiency. Three dimensional computational simulation is used to investigate the feasibility of ethanol and gasoline-ethanol mixtures as a fuel over varying compression ratios in a GDI engine. ANSYS Workbench is used to build a dynamic mesh of the varying compression ratio models, in conjunction with SolidWorks modeling software. To simulate flow physics, fuel injection, and combustion in the engine, ANSYS Fluent is employed. A parametric study of the effect of spark timing and compression ratio under ethanol operation at cruise RPM is performed. Additionally, a dual-injector gasoline-ethanol setup is implemented for the GDI engine and the effects of injection timing and mixture fraction of fuel is analyzed. Both ethanol and bi-fuel operation settings are found to provide significantly higher horsepower than the stock GDI engine. The dual-injector, bi-fuel operation is found to provide a specific fuel consumption comparable to the stock engine while providing substantially higher output. The results yield a promising fuel delivery strategy which can be appealing to many direct injection engine applications.
Department or Program
Department of Mechanical and Materials Engineering
Year Degree Awarded
Copyright 2012, all rights reserved. This open access ETD is published by Wright State University and OhioLINK.