INTERNAL COMBUSTION ENGINE

摘要

An internal combustion engine is provided, which is capable of performing normal perturbation for a long period of time according to changes in a valve with time such as contamination, and wear. A gas engine 1 is configured to detect a stoichiometric air-fuel ratio by oxygen sensors 11 and 15 and to perform the perturbation using a solenoid valve 21. The gas engine 1 includes: an A/F valve 22 disposed in parallel with the solenoid valve 21; and a control unit 10. The control unit 10 controls to perform the perturbation in an intermediate region 21a of an opening/closing region of the solenoid valve 21 by detecting time deviations T1 and T2 of an air-fuel ratio that change due to the perturbation and by opening the A/F valve 22 according to the time deviations T1 and T2.