Mixture controller for an internal combustion engine

US5586543A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

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

Key dates

• Filing date: Jan 17, 1995
• Grant date: Dec 24, 1996
• Expiry date: Jan 17, 2015

Classification

• Technology area (CPC F): Mechanical Engineering; Lighting; Heating
• CPC primary: F02D41/1477
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

A mixture controller for adjusting an output value, which is outputted by a PI two-point controller, to control the air/fuel ratio of a mixture supplied to an internal combustion engine to a pregiven value. The engine produces an exhaust-gas flow during operation and has an oxygen probe mounted in the exhaust-gas flow. The mixture controller continuously detects the signal of the oxygen probe to obtain sequential measurement values of the signal. A check is made as to whether a currently detected measurement value of the signal has crossed over a threshold value in the lean or rich direction compared to the previously detected measurement value of the signal. The output value is changed when a crossover of the signal in the lean direction is present by shifting the output value with a large step via a P-jump in the rich direction and starting an integration of the output value in the rich direction from a previous lean direction. The output value is also changed when a crossover of the signal in the rich direction is present by stopping the integration of the output value in the rich direction and starting an integration in the lean direction after a pregiven delay time has elapsed…