Demonstration of Advanced Emission Controls for Nonroad SI Class II Engines

The U.S. Environmental Protection Agency has completed a program to demonstrate the feasibility of using low-cost engine management systems and modern, high-efficiency exhaust catalysts for nonroad spark ignition gasoline Class II engines (sub-19 kW, greater than 225 cc). Low-cost electronic engine management and fuel injection systems originally developed for motor-scooter and small motorcycle applications were installed on two 500cc single-cylinder spark-ignition lawn-and-garden engines. Integrated catalyst-muffler systems were developed for both engines and fuel control was calibrated to achieve emission control goals while maintaining or improving fuel consumption, engine durability and performance. NOx+HC emissions were reduced approximately 75% and brake-specific fuel-consumption improved by 6 to 12%. .