Air/fuel ratio control system for outboard motor engine

摘要

In an air/fuel ratio control system for an outboard motor engine, a learned correction coefficient KTIMn used in open-loop control for correcting a basic fuel injection amount to be supplied to the engine, is updated only when the manifold absolute pressure PBA (indicative of engine load) is within a predetermined range relative to the engine speed NE concerned. As a result, the air/fuel ratio can be accurately controlled to one other than the stoichiometric air/fuel ratio, even when an O₂ sensor that produces an output whose property only changes near the stoichiometeic air/fuel ratio is used.