Detection of oxidisable materials in exhaust gas of combustion engine - using Wheatstone bridge in which one branch has active pellistor as gas exhaust sensor while other branch has non-active pellistor

摘要

A exhaust material measuring method uses a measuring bridge with at least two sensors (D,R) arranged in the exhaust gas outlet of a combustion engine. One of the sensors forms an active sensor (D) by burning oxidisable materials on its surface which is heated by the resistance, thereby increasing its temperature dependent resistance. The other sensor (R) serves as a reference sensor depending on similar environmental parameters without increasing its temperature by the presence of combustible materials. Oxidisable materials are detected by measuring voltage variations with the measuring bridge, a flow of air being delivered to the exhaust gas outlet.