Semester

Fall

Date of Graduation

2011

Document Type

Thesis

Degree Type

MS

College

Statler College of Engineering and Mineral Resources

Department

Mechanical and Aerospace Engineering

Committee Chair

Benjamin Shade

Abstract

Over the past two decades increasingly strict emissions regulations have been implemented for on-road diesel engines. Additionally, reduced fuel consumption has recently become a priority for government regulatory agencies promising more stringent regulations on the horizon. This desire for less polluting, more efficient vehicles has fueled advanced engine research and development. Advanced combustion regimes such as homogeneous charge compression ignition (HCCI), premixed charge compression ignition (PCCI), and low temperature combustion (LTC) are topics at the forefront of this research. Each of these advanced combustion regimes essentially follow the same principle in which a homogeneous or near-homogeneous air and fuel mixture combusted at low temperatures can provide reductions in oxides of nitrogen (NOX), soot and fuel consumption while increasing brake-thermal efficiency.;Research performed at the Center for Alternative Fuels, Engines, and Emissions (CAFEE) at West Virginia University focused on achieving advanced combustion utilizing a European 1.9 Liter General Motors light-duty diesel engine. The engine was retrofit with a fully programmable electronic control unit (ECU) allowing for flexible control of fuel injection parameters, exhaust gas recirculation (EGR), boost pressure, and other independent control variables. Four different fuels with varying fuel properties, including but not limited to cetane number, aromatic content, 90 percent distillation temperature, and specific gravity, were tested during this research. Advanced injection strategies performed on each fuel were used to determine the effects of the fuel injection parameters, EGR, boost pressure, and fuel properties on advanced combustion.;Implementation of a single injection strategy with increased EGR levels and an advanced start of injection (SOI) timing resulted in significantly reduced NOX and soot emissions. Undesirable fuel consumption, extremely high carbon monoxide (CO) and hydrocarbon (HC) emissions, and in-cylinder pressure rise rates accompanying this strategy led to the development of a split injection strategy. Injection of 50 percent of the fuel at an early SOI timing, and the rest near top dead center reduced HC and CO emissions, improved fuel consumption from baseline tests, and retained NOX and soot emissions reductions. This split injection strategy also resulted in much safer in-cylinder pressure rise rates. Through testing of the different fuels it became apparent that cetane number was the dominant fuel property affecting gaseous emissions, soot, and in-cylinder pressure rise rates. Lower gaseous emissions were measured during the operation of high cetane number fuels. Fuels with lower cetane number resulted in less soot formation and lower in-cylinder pressure rise rates.

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