Evaporative fuel processing apparatus for a lean-burn internal combustion engine

摘要

In an internal combustion engine in which a throttle valve is substantially fully opened in most of operating regions such as an in-cylinder injection type internal combustion engine, an object of the present invention is to provide a technique capable of effectively processing an evaporative fuel while stabilizing a combustion state of the internal combustion engine even in the case that an amount of evaporative fuel generated in a fuel tank or the like is increased. To achieve this object, according to an evaporative fuel processing apparatus of the present invention, a purge amount of evaporative fuel is increased by increasing a differential pressure between an upstream portion and a downstream portion of a purge passage, and the differential pressure is adjusted in accordance with the combustion state of the internal combustion engine at that time, thereby making it possible to purge the maximum amount of evaporative fuel within a range in which the combustion state is not unstabilized.