Emissions reduction benefits of adapting electronic closed loop fueling control on a mechanically controlled spark-ignited engine

Recent government gaseous exhaust emissions regulations have been expanded to include a variety of mobile air pollution sources. Exhaust emissions from non-road engines have recently become a focus of Environmental Protection Agency (EPA) regulations. The term "non-road engines" covers many industrial and general aviation (GA) type engines that are currently unregulated. This study examines the gaseous exhaust gas emissions produced from a mechanically-controlled Lycoming IO-360-B GA engine and studies the benefits of conversion to electronic fuel injection with closed loop feedback control. The study concludes that the overall gaseous exhaust emissions from the unmodified engine far exceed current automotive standards. The conversion to electronic fuel injection substantially reduces the exhaust emissions produced by the engine (particularly unburned hydrocarbon and carbon monoxide emissions), but still not to the point of meeting prevailing automotive regulations. The engine's quiescent, low swirl, low turbulence and low compression ratio combustion chamber design restricts the total benefits realized from the conversion. These emissions reduction benefits demonstrated here are immediately applicable to other spark-ignited non-road or utility engines, such as those used in portable power generation, construction, irrigation and ground power applications.