Date of Award

5-2008

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Science

First Advisor

Dr. Mohamed Younes

Second Advisor

Dr. Mohamed Gadalla

Third Advisor

Dr. Emad Elnajjar

Abstract

This study examines the effects of adding the water to the intake air of a dual fuel engine on the performance and combustion noise. Dual fuel engine is a diesel engine using small amount (5%) liquid diesel fuel as a pilot fuel and burns a liquefied petroleum gas as the main fuel. The addition of water to the combustion chamber has known effects on reducing the dangerous emission of nitrogen oxides. Previous research has attributed the observed reduction of nitrogen oxide emissions to a suppression of flame temperature due to quenching effects from the water, thereby reducing thermal NOx formation.

The thesis highlights the effects on the performance, CO/HC/Smoke exhaust emission and combustion noise of the dual fuel engine. Experimental procedures conducted using a Ricardo diesel version variable compression research engine are discussed. Results from testing dual fuel engine with varying the added water to fuel ratios and other design and operating parameters will be presented and discussed.

The data shows slight decrease in the power output with increasing the amount of water added. This drop can be recovered by reducing the compression ratio of the engine. The addition of water also shows an increase in the combustion noise, however the noise can be decreased by increasing the engine speed, reducing the pilot fuel mass, retarding the injection timing or reducing the compression ratio. CO and He emissions have shown slight increase but still within the accepted range and can be reduced further by a catalytic converter. Exhaust opacity has shown slight increase with adding more water; however it can be also reduced by reducing the mass of pilot fuel.

Recommendations are given for further studies, including the use of CFD simulation and the use of more water amounts.

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