Exhaust gas analyzer of this sensor and to create smaller devices.Typical NDIR sensors cost in the (US) $100 to $1000 range. Used by older aircraft, the Cambridge Mixture Indicator displayed air-fuel ratio by measuring the thermal conductivity of exhaust gas. It was manufactured by the Cambridge Instrument Company. This device was installed on airplanes in the 1930s, including the Lockheed Model 10 Electra flown by Amelia Earhart on her last flight. Exhaust gas analyzer An exhaust gas analyser or exhaust CO analyser is an instrument for the measurement of carbon monoxide among other gases in the exhaust, caused by an incorrect combustion, the
Exhaust gas recirculation the engine was running. Difficult starting, rough idling, and reduced performance and fuel economy resulted. By 1973, an EGR valve controlled by manifold vacuum opened or closed to admit exhaust to the intake tract only under certain conditions. Control systems grew more sophisticated as automakers gained experience; Chrysler's "Coolant Controlled Exhaust Gas Recirculation" system of 1973 exemplified this evolution: a coolant temperature sensor blocked vacuum to the EGR valve until the engine reached normal operating temperature. This prevented driveability problems due to unnecessary exhaust induction; NOx forms under elevated temperature conditions generally not present with a cold engine. Moreover, the