To accurately set an air-fuel ratio by taking a filling condition of oxygen for a catalyst at this point of time into consideration when an air-fuel ratio of mixed air is to be set, and diagnosing the catalyst based on a relation between an oxygen accumulation capacity and a deterioration condition.
A primary controller 2.6 is provided for the control system of an engine 2.1 provided with a trigonal catalyst 2.2 in its exhaust system. The result of evaluation at the parameter evaluation 2.3 inputting an exhaust gas flow rate m*(t) and deviations from the quantity of oxygen contained, is inputted in a catalyst model 2.4 and a feed block 2.5, and the degree ROL of relative oxygen filling is thereby obtained by the catalyst model 2.4 corresponding to an oxygen accumulation model. Respective data such as the degree ROL of relative oxygen filling, the integration speeds KIN and KIP of a positive and a negative deviation from the feed block 2.5, the aforesaid flow rate m*(t) and the deviations Δλ, is fed to the primary controller 2.6, and a λ factor ΔFλ is operated so as to be made serviceable to the correction of a fuel injection time based on the reference value of the degree ROL of relative oxygen filling for the catalyst.
EERIHI SHIYUNAIDAA
RIYUUDEIGAA DAIBERUTO
HANSU PEETAA GEERINGU
KURISUCHIYAN RODOUNAA
ESUFUANDEIAA SHIYAFUAI
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