METHOD FOR CONTROLLING ENGINE TO MAINTAIN PERFORMANCE OF OXIDATION CATALYST

摘要

The present invention provides a method for controlling an engine to maintain performance of an oxidation catalyst for purifying exhaust gas, for a compressed natural gas engine operating in a lean-burn state. The method for controlling an engine to maintain performance of an oxidation catalyst includes: a lean-burn combustion step of combusting a fuel in the compressed natural gas engine in order for an air-fuel equivalent ratio to be 1 or less; an activity calculation step of calculating an activity of the oxidation catalyst purifying the exhaust gas of the engine; a regeneration determination step of determining whether regeneration for recovering the activity of the oxidation catalyst is necessary, according to the calculated activity of the oxidation catalyst and a driving state of the engine; and a catalyst regeneration step of combusting the fuel by increasing the air-fuel equivalent ratio to 1.10-1.20 in case that the activity of the oxidation catalyst is a predetermined reference value or less in the regeneration determination step and a revolution number per minute of the engine is equal to or less than a predetermined revolution number.