EMPLOYING EXPERIMENTAL AND COMPUTATIONAL FLUID DYNAMIC METHODS TO REDUCE METHANE EMISSIONS IN LARGE BORE TWO-STROKE NATURAL GAS ENGINES BY USING IN-CYLINDER TECHNIQUES

Abstract

Methane slip from internal combustion engines is an issue that escalates the increase of theaverage global temperature society is seeing today. Governmental policy has pushed for a reduction of emissions from internal combustion engines to help combat this change in global weather. The purpose of this research was to investigate multiple in-cylinder techniques that were designed to reduce the engine out emissions of a large bore two-stroke natural gas integral compressor engine. Experimental and computational fluid dynamic simulations were used throughout the research. The first technique investigated was using a hydrogen and natural gas blended fuel compared to a solely natural gas fuel. The second technique was designing a pre-combustion chamber that addressed areas of poor or incomplete combustion. Finally, the third technique studied was the injection of a premixed natural gas and air charge into the pre-combustion chamber to improve homogeneity of the pre-combustion chamber. Using hydrogen as a fuel saw reductions in methane emissions of nearly 30%. The optimized prechamber design saw decreases between 22% and 31%, depending on the engines operating conditions. The premixed fuel and air injection did not produce any favorable results. The reductions seen in the first two techniques show that large dimunitions in emissions are not only possible, but likely across multiple platforms.