Method and apparatus for controlling the composition of the combustible mixture of an engine

摘要

An internal combustion engine is provided with an ion current sensor in the exhaust conduit. The sensor may be simply a spark plug across which is applied the vehicle battery voltage. The operation of the engine at various values of mixture composition yields characteristic curves for the ion current and for the fluctuations in the ion current as a function of the air number. These characteristic data are used to provide set point values against which the prevailing ion current is compared. If a set point value is exceeded, the fuel-air mixture is adjusted accordingly by an integral controller.