Catalytic Particulate Control for Off-Highway Diesels

The widespread use of diesel engines for industrial power plants in enclosed environments has long caused concern over the health effects of long-term exposure to diesel exhaust emissions. This concern has led to developments in engine design and exhaust after-treatment aimed at significantly reducing the pollutant levels in diesel exhaust.

The basic principles of diesel emissions control using a Catalytic Trap Oxidizer were developed by Johnson Matthey for use on light-duty road vehicles. The system makes use of a radial-flow impingement filter structure supporting a specially formulated precious metal catalyst. The filter is effective in trapping particulates and enables their removal, by catalytic oxidation, at attainable temperatures. The catalyst is also effective in enabling oxidation of gaseous organic and carbon monoxide emissions at low temperature.

The experience gained on light-duty vehicles is now being used as the basis of a program to develop further and evaluate the technology in off-road applications. Initial studies on test-bed engines have led to development of prototype systems currently in actual service testing. Catalytic Trap Oxidizer performance data are presented on a variety of industrial diesel applications, together with concepts for assisted regeneration.