Experimental analysis of a small engine operating on diesel-natural gas and soybean vegetable oil-natural gas

The purpose of this article is to investigate the effects of an unmodified small engine operating on diesel oil-natural gas (DO-NG) and soybean vegetable oil-natural gas at intermediate load. This is significant to reduce our dependency from diesel oil and the emissions of warming gases. Although it is important to highlight that the literature regarding this experimental conditions is scarce, due the use of soybean vegetable oil and natural gas in dual-fuel mode, characterizing a totally diesel oil replacement. The experiments were conducted in a single-cylinder diesel engine coupled to a generator. Natural gas was introduced at the engine intake manifold. The diesel oil and soybean vegetable oil substitution rates were from 16.6 to 91.1% and from 17.6 to 90.7%, respectively. The experimental results were satisfactory being observed a decrease in specific fuel consumption (until 80% of replacement) and a maximum reduction around 80% in NOx emissions. On the other hand, there have been an increase in CO emissions and a decrease in thermal efficiency for all conditions performed. Soybean vegetable oil-natural gas operation demonstrates same trends with a little higher specific fuel consumption and NOx emission than DO-NG.