Method and apparatus for controlling operational variables of an internal combustion engine

US4223644A · kind A · utility

Assignee

• Robert Bosch GmbH · DE

Inventors

• Reinhard Latsch · Leinfelden, DE
• Peter Schmidt · Schwieberdingen, DE
• Josef Wahl

Key dates

• Filing date: Nov 13, 1978
• Grant date: Sep 23, 1980
• Expiry date: Nov 13, 1998

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02T10/40
• WIPO field: Engines, pumps, turbines
• WIPO sector: Mechanical engineering

Abstract

A principal operational variable of an internal combustion engine, for example the fuel-air mixture ratio, is controlled by superposition of three separate control steps. The basic setting of a control variable is obtained with a relatively coarse forward control, for example a carburetor in the case of fuel-air mixture control. Superimposed on this basic control is a refined forward control step which is based on the prevailing magnitudes of at least one operational variable, preferably the engine speed and the throttle valve position, and which applies a multiplicative correction to the basic setting of the fuel-air mixture. The third superimposed control step is a feedback control of the fuel-air mixture within the range of correction applied by the second control steps but based on still another engine variable, in particular the exhaust gas composition as sensed by an oxygen sensor (.lambda.-sensor). After comparison with the reference signal, the .lambda.-sensor signal is multiplied with the sum of the values of the basic air factor setting and the first corrective air factor setting. The data required for applying the first correction are preferably stored in a digital memor…