Method for adjusting the fuel/air mixture for an internal combustion engine after an overrun phase of operation

US5438826A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Frank Blischke · Stuttgart, DE
• Klaus Hirschmann · Leonberg, DE
• Lothar Raff · Waiblingen, DE
• Eberhard Schnaibel · Hemmingen, DE

Key dates

• Filing date: Nov 1, 1993
• Grant date: Aug 8, 1995
• Expiry date: Nov 1, 2013

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F02D41/1475
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

The invention is directed to a method for reducing the exhaust-gas emissions of an internal combustion engine which is equipped with a lambda control and a catalytic converter and for which the metering of fuel can be interrupted in dependence upon operating parameters. The method is characterized in that the engine at first is operated with a rich fuel/air mixture during transition from operation without fuel metering to operation with fuel metering. The oxygen deficiency associated therewith compensates the oxygen excess which is stored in the catalytic converter when the metering of fuel is interrupted. An operating state wherein oxygen is loaded therefore occurs quickly after a fuel cutoff. This operating state also defines an optimum at steady state and this is advantageous especially for the conversion of nitrogen oxide.