Electronic control system for an engine and the method thereof

摘要: The air-fuel ratio of a lean-burn engine is controlled so as to be adjusted with low NOx concentration. As this done, an actual combustion fluctuating rate detected from the cylinder pressure, and rich side respect lean-side limit, whereby satisfactory driving performance can secured. state exhaust determined by concentration, lean allowable limit exhaust. On other hand, value changing under conditions concerned are compared, while same compared. EGR amount decreased when higher than value, increased rate. Thus, decreased.