Exhaust Gas Recirculation for Reducing the Oxides of Nitrogen in Spark Ignition Engines PDF

Keywords

exhaust gas, nitrogen, ignition engines

Abstract

Spark-ignition engine exhaust gases contain oxides of nitrogen (NO.), carbon monoxide (CO), and organic compounds that are unburned or partially burned hydrocarbons (HC). These exhaust emissions are presently subject to regulatory control. Of these harmful pollutants, NO. emissions are the hardest to control under the current status of emission control technology. The present paper deals with the use of the exhaust gas recirculation (EGR) for NO. control. The NO. concentration in the exhaust was studied experimentally, and theoretically using the method of element potential over a wide range of fuel-air ratios, percentage of exhaust gas recycled, and engine speeds. Comparison of the measured and calculated exhaust nitric oxide concentration shows good agreement overall operating conditions. To make the EGR method effective over a wide range of operating conditions, two EGR maps were constructed. They can be used as input data to a closed loop control system, to regulate the EGR rate required to reduce the NO. emission to the reduction target.