Sensor controlled pyrolysis in consumer ovens

Pyrolysis means to heat a material up to high temperatures at which its molecular structure is thermally cracked. The residues of the heated material are gases and ashes. In modern consumer ovens this method is used to clean the walls of the oven cavity. The cavity is heated up to about 480°C. At this temperature the dirt sticking on the walls is thermally cracked into gases and ashes. The approach of the system described in this paper is to estimate the quantity of dirt to be pyrolysed in the cavity. This is done by using a gas sensor. The sensor measures the concentration of the gaseous residues in the exhaust air of the oven. Evaluation of the sensor signal makes it possible to minimise the energy consumption during the process. Furthermore, the sensor can be used as a safety device.