Post fuel injection control of an internal-combustion engine

摘要

The present invention provides a fuel control for an internal-combustion engine having an exhaust gas purifying device that is disposed in an exhaust system of the engine. A reducing agent is supplied to the exhaust gas purifying device by injecting fuel in an expansion stroke or an exhaust stroke of the engine. An intake air amount is decreased during the fuel injection for the supply of the reducing agent. The fuel control also includes advancing an injection timing (62,63,64,66) of the fuel injection for the supply of the reducing agent when an actual intake air amount (GA) is less than a desired intake air amount (GACMD) or when an actual boost pressure (BPA) is higher than a desired boost pressure (BPCMD). The advancement of the injection timing improves the combustibility of engine while decreasing the HC exhaust amount.