Selbstdiagnose Vorrichtung eines Verbrennungsmotors

摘要

The invention relates to an engine self-diagnosis system (1) capable of performing diagnosis of the light-off performance of a catalyst (50) at a low cost and high accuracy without requiring addition or improvement of a sensor, etc. The engine self-diagnosis system (1) comprises a unit (140) for directly or indirectly detecting performance A of an exhaust cleaning catalyst (50) when temperature of the catalyst (50) is within a predetermined temperature range, and a unit (150) for, based on the detected catalyst performance A, estimating performance B of the catalyst (50), which is resulted when the temperature of the catalyst is outside the predetermined temperature range.