Oxidation Catalyst Systems for Emission Control of LPG-Powered Forklift Trucks

An oxidation catalyst was installed on an industrial LPG-powered forklift truck. For high conversion efficiency in an oxidation system on a rich burning engine a secondary air supply to the catalyst is necessary. Two simple and cost-effective ways of secondary air supply were tested: an air valve and a venturi type injector. The amount of secondary air supplied by both devices was measured under a variety of conditions - different engine speed, load and exhaust system pressure.

Carbon monoxide emissions and the catalyst performance were measured and evaluated in terms of the secondary air flow.

Advantages and drawbacks of the air valve and venturi injector systems are discussed and compared.