Experimental Research on the Effects of Oxygen-Enriched Air on Combustion in a Small Spark-Ignition Engine

An investigation on the effects of oxygen-enriched air on engine performance was proposed. This investigation focuses on combustion performance. As the oxygen concentration of the air for combustion increases, the heat of combustion for an engine of the same size would increase. The size (displacement) of an engine can be effectively reduced to achieve the same power. Oxygen- enriched air will affect the combustion process and the overall engine thermodynamics. For example, as oxygen concentration is increased, under the same operating conditions, combustion temperature and cylinder pressure will be increased. The purpose of this study was to quantify these results for a range of operating conditions. Results include detailed thermodynamic output of pressures and other properties as related to the oxygen concentration of the air used for combustion. Results also include engine performance parameters such as power, torque, fuel consumption, and thermal efficiency. In one case, the combustion performance of the engine was recorded for an equivalent load with different oxygen concentrations of air. For air enriched with 24% oxygen, the cylinder pressure was increased by about 15%, the heat of combustion increased, and both the maximum pressure and the increased heat of combustion were achieved more quickly. Other results were recorded.