Semiconductor gas sensors as control monitors for NO{sub}x storage catalytic converters

摘要

Silicon Carbide (SiC)-based high temperature semi-conductor gas sensors were tested for potential applications in the closed-loop control of NO{sub}x storage catalytic converters. The exhaust gas composition behind a storage catalyst was simulated by synthetic gas mixtures supplied from a gas-blending manifold. In lean-oxidizing ambients the sensors produced signals opposite in sign upon the appearance of NO{sub}x on the one hand and mixtures of HC and CO on the other hand. Transient gas measurements revealed response times ranging between several milliseconds for HC and several seconds for NO{sub}x. These features render SiC-based sensors potentially useful for the control of NO{sub}x storage catalytic converters.