AIR-FUEL RATIO CONTROLLING DEVICE OF INTERNAL COMBUSTION ENGINE AND PLANT CONTROLLING DEVICE

摘要

PROBLEM TO BE SOLVED: To provide an air-fuel ratio controlling device of internal combustion engine for a system in which the air-fuel ratio of internal combustion engine is controlled to settle the output of exhaust gas sensor on the downstream side of catalyst device toward a predetermined target value, that compensates the influence of dead time on the exhaust system containing the catalyst device, while further increasing accuracy and quick response performance of the control for settling the exhaust gas sensor output to target value. SOLUTION: This device is provided with a reference value setting part 11 that variably sets a reference air-fuel ratio FLAF/BASE to send to an exhaust system containing a catalyst device in accordance with a componentμadp. The componentμadp is based on the adaptation law of air-fuel ratio control amountμsl, which is generated by a control instrument 27 through processing of adaptive sliding mode control in order to settle an O2 sensor output VO2/OUT of the sensor located downstream of the catalyst device toward a target value VO2/TARGET. An estimation instrument 26 estimates a deviation VO2 between an O2 sensor output after dead time of the exhaust system and a target output by using a deviation kact between the determined reference value FLAF/BASE and a detected air-fuel ratio KACT. The estimated deviation VO2 is sent to the control instrument 27.