Temp. regulation for exhaust gas probe - using electrically heated wire with its resistance depending on temp. and probe positioned in exhaust gas pipe of IC engine

摘要

The inner resistance of the exhaust gas probe or the heating unit is measured in the known manner for determining the temperature of the exhaust gas probe. The measured inner resistance is regulated by means of a continuous regulation to a predetermined desired value. The desired value corresponds to a temperature value, which the exhaust gas probe assumes with a specified operation condition of the IC engine with higher load conditions without the supply of electrical heating power. The system for carrying out the method includes the exhaust gas probe (3), a control unit (4), a mixture metering unit, a heating unit (8), a controllable switch (9) arranged between the heating unit and the voltage supply (Ub), a constant heat regulator (10) and a desired value/actual value comparator (11). ADVANTAGE - Probes temperature is kept constant within narrow range, without fluctuations occurring in lambda signal and compensates influence of unforeseen interference. Ensures quick heating of cold probe without risk of overheating.