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 Clogged EGR valves can sometimes be cleaned, but replacement is necessary if the valve is faulty. In modern diesel engines, the EGR gas is cooled with a heat exchanger to allow the introduction of a greater mass of recirculated gas. Unlike spark-ignition engines, diesels are not limited by the need for a contiguous flamefront; furthermore, since diesels always operate with excess air, they benefit from EGR rates as high as 50% (at idle, when there is otherwise a large excess of air) in controlling NOx emissions. Exhaust recirculated back into the cylinder can increase engine wear as carbon particulates wash