The introduction of stringent emission legislation has rendered many existing emission-control measures inadequate, and the catalytic converter is one of these. The problem is that the catalyst does not operate effectively at temperatures below 250-300 degrees C from a cold start. This paper presents a method that reaches rapid catalyst lightoff by means of a high value of ignition retard, and thereby obviates the need for an external heat source, such as with electrically heated or burner/afterburner-assisted catalysts. Proper control strategies show that the catalyst could reach its lightoff temperature within 50 seconds when both the engine and the catalyst are initially cold. Emission data of unburnt hydrocarbons and carbon monoxide at both the upstream and downstream sides of a catalyst converter were measured, and the results show that significant reductions in emissions can be obtained with appropriate ignition-control strategies.