The Significance of High Value of Ignition Retard Control on the Catalyst Lightoff

Abstract

<div class="htmlview paragraph">Ever stringent emission legislation has called for more advanced measures for petrol engine emission control. The main chanllenge is to largely cut off the engine cold-start emissions. The problem is that the catalytic converter does not operate effectively at temperature below the range of 250 - 300 °C at engine cold start. This paper presents an alternative approach, which needs no assistance from the external heat source such as electrically heating or burner/afterburner-assisting, etc, for rapid light-off an automotive catalyst using high value of ignition retard control. Proper control strategies permit a catalyst to reach lightoff within 50 seconds from cold-start. Emission data of unburnt hydrocarbons (in terms of hexane-equivalence) and carbon monoxide at both the upstream and downstream of a catalytic converter are measured. Results show that significant reduction in emissions can be achieved with proper ignition control strategies. The effect of high value ignition retard on the cold-start NOx emission is also briefly discussed.</div>