Abstract: A device is proposed for regulating the fuel-air ratio in the operating mixture of an internal combustion engine and for monitoring the operational readiness of a .lambda. sensor controlling the regulating device and functioning by the principle of ion conduction in solid electrolytes. The .lambda. sensor has an adjustable, constant reference voltage switched opposite to it. The reference voltage approximately equals the average sensor output voltage. The level of the resultant voltage, which is established with the aid of the resultant current and has values located symmetrically with respect to the reference voltage, is monitored by comparator devices. The output signal of the comparator devices is logically processed and furnishes a signal as to the operational readiness of the sensor.

Abstract: A method and an apparatus for regulating the fuel-air ratio of the operational mixture of an internal combustion engine and for monitoring the operational readiness of a .lambda. sensor controlling the regulating apparatus and functioning according to the principle of ionic conduction in fixed electrolytes. A constant reference voltage which approximately corresponds to the average sensor output voltage is connected opposite to the .lambda. sensor. The level of the resultant voltage thus established, the values of which are disposed symmetrically relative to the reference voltage, is utilized, along with the cooperation of a resultant electric current which causes a voltage drop across the temperature-dependent internal resistance of the .lambda. sensor as a gauge for the operational readiness of the .lambda. sensor.

Abstract: An apparatus for the open-loop or closed-loop control of the composition of the mixture desired in the combustion chamber of an internal combustion engine, which includes an exhaust gas sensor whose output signal together with other operational parameters, determines the mixture composition. The essential component of the apparatus is a storage unit with which charging and discharging sources controllable in accordance with the sensor signal are associated, wherein the magnitude of the charging and discharging signal is dependent on operational parameters. The storage unit may comprise a capacitor or a resistor-capacitor combination having one terminal connected to ground and another terminal efficiently connected with an operational voltage connection, so as to have in this manner an unequivocal association with a fixed potential.