Engine controller

Abstract

An engine controller controlling an engine including an occlusion reduction catalyst in an exhaust device includes a fuel injection controller that controls a fuel injection amount of an injector, an EGR controller that controls an EGR device, a sulfur purge determiner that determines whether sulfur purging of the catalyst is to be performed, and a sulfur purge controller that executes sulfur purge control if the sulfur purging is performed. The sulfur purge control involves performing a fuel injection to achieve a rich air-fuel ratio at an inlet of the catalyst and prohibiting the exhaust-gas introduction. The sulfur purge controller executes sulfur-purge standby control when a sulfur-purge standby condition is satisfied, and resumes the sulfur purge control when the condition becomes non-satisfied after starting the sulfur-purge standby control. The sulfur-purge standby control involves performing the fuel injection to nearly achieve a stoichiometric air-fuel ratio and prohibiting the exhaust-gas introduction.