Steady State and Transient Response Characteristics of Commercial Carbon Monoxide Sensors

Abstract

Suggestions have been made to include sensor platforms that are capable of detecting potential bleed air contamination events on commercial airliners to protect the health and safety of aircraft passengers and crew. Detecting high levels of carbon monoxide in the bleed air system of an aircraft may indicate a contamination event since many of the suspected bleed air contaminants evolve carbon monoxide at the elevated temperatures seen in the compressor stages of the engine. Because the levels of carbon monoxide are not expected to reach a steady-state during a transitory contamination event, it is important to understand the transient response characteristics of carbon monoxide sensors. Several electrochemical carbon monoxide sensors were tested in a chamber designed to provide an almost instantaneous gas concentration change. The sensors were evaluated for their response time and accuracy. The sensors' initial response rates were found to be linear with respect to the imposed concentrations and this characteristic may enable estimates of the levels of contamination events due to brief indications of high levels of carbon monoxide.