초록 ▼

A method and apparatus for desulfating a NO.sub.x trap is proposed wherein the SO.sub.x purge temperature is achieved by modulating the amplitude of the A/F of the mixture supplied to the engine thereby storing oxygen in the trap during lean engine cylinder events and generating the required exother

A method and apparatus for desulfating a NO.sub.x trap is proposed wherein the SO.sub.x purge temperature is achieved by modulating the amplitude of the A/F of the mixture supplied to the engine thereby storing oxygen in the trap during lean engine cylinder events and generating the required exotherm during rich engine cylinder events.

대표청구항 ▼

[ What is claimed is:] [1.] A method of operating an engine supplied with a mixture of fuel and air and having a trap located in an exhaust path of the engine, said method comprising a sequence of the following steps:estimating the amount of contaminant accumulated in the trap;amplitude modulating t

[ What is claimed is:] [1.] A method of operating an engine supplied with a mixture of fuel and air and having a trap located in an exhaust path of the engine, said method comprising a sequence of the following steps:estimating the amount of contaminant accumulated in the trap;amplitude modulating the A/F of the mixture supplied to the engine between a lean and a rich mixture when the estimated amount of contaminant reaches a threshold amount to thereby raise the temperature of the trap to a predetermined temperature;purging the trap of contaminant when said predetermined temperature is reached;terminating the purging of said trap when a predetermined purge criteria is met.