| Exhaust gas analyser | An exhaust gas analyser is a measuring instrument that serves to determine the volume fractions of specified components of the exhaust gas of a motor vehicle engine with spark ignition at the moisture level of the sample analysed. These gas components are carbon monoxide (CO), carbon dioxide (CO2), oxygen (O2) and hydrocarbons (HC). The content of hydrocarbons has to be expressed as concentration of n-hexane (C6H14), measured with near-infrared absorption techniques. The volume fractions of the gas components are expressed as a percentage (% vol) for CO, CO2 and O2 and in parts per million (ppm vol) for HC. Moreover, an exhaust gas analyser calculates the lambda value from the volume fractions of the components of the exhaust gas. |
| Lambda | Lambda is a dimensionless value representative of the burning efficiency of an engine in terms of air/fuel ratio in the exhaust gases. It is determined with a reference standardised formula. |