摘要 |
<p>A diesel (compression ignition) engine having combustion management means and an exhaust gas aftertreatment system without an NOx trap, which system comprising a platinum group metal (PGM) catalyst liable to be poisoned by fuel sulphur to cause significant degradation of catalyst performance, which engine is fuelled, at least intermittently, by a diesel fuel containing such levels of sulphur as to cause poisoning of the catalyst, wherein the combustion management means is effective to modulate the air/fuel ratio (μ) to 0.90, preferably 0.95, or richer for a time which is in aggregate sufficient to cause release of significant quantities of sulphur-containing species from the catalyst or catalyst components, whereby the catalyst is regenerated.</p> |