Research Projects

Project at a Glance

Project Status: complete

Report Published April 1999:

Title: Three-way catalyst technology for off-road equipment powered by gasoline and LPG engines.

Principal Investigator / Author(s): Ingalls, Melvin & James Carroll

Contractor: Southwest Research Institute

Contract Number: 95-340

Research Program Area: Emissions Monitoring & Control

Topic Areas: Mobile Sources & Fuels


Research was done to demonstrate the feasibility of using closed-loop three-way catalyst (TWC) technology in off-road large spark-ignited (LSI) engine applications to meet California State Implementation Plan (SIP) emission reduction goals. Available technology was investigated for applicability to engines in this category. A technical Adviry Committee, made up of engine and equipment manufacturers and representatives from industry organizations, was formed to provide input on technical issues. Appropriate test cycles were recommmended, and five representative engines were selected and baseline emission tested. Total feasible emission reductions were calculated. The retail price equivalent (RPE) for the recommended emission control technology was determined and cost-effectiveness was calculated. Emission standards necessary to meet SIP goals were recommended.

Two emission reduction systems, incorporating three-way catalysts with electronic fuel control, were designed, constructed and emission tested. Emissions durability testing was then performed to demonstrate the feasibility of application of these technologies to category equipment. Results showed that low emission levels, easily meeting CARB's newly adopted LSI emission standards, could be achieved.

Engine identification is coded in report sections presenting emission results. Manufacturers agreed to loan engines to the program for testing, providing results were coded to maintain manufacturer confidentiality.


For questions regarding this research project, including available data and progress status, contact: Heather Choi at (916) 322-3893

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