System and method for monitoring the efficiency of a catalyst treating engine exhaust

摘要

A method for monitoring the efficiency of a catalyst includes providing an oxygen sensor between an engine and the catalyst to generate an output signal indicative of oxygen content. The output signal is sampled to provide a first value indicative of the oxygen content of untreated exhaust. The exhaust is allowed to flow through the catalyst to produce treated exhaust and then the treated exhaust is caused to flow back to the oxygen sensor. The output signal is again sampled to provide a second value indicative of the oxygen content of treated exhaust. The second value is compared to the first value to provide an indication of the efficiency of the catalyst.