Method and system for detection of hydrocarbon species in a gas

The present invention relates generally to gas sensing systems and vehicle emission detection systems. More particularly, the present invention relates to a method and system for detecting and measuring various species of hydrocarbons in a gas, such as a vehicle exhaust. The measurements detected by the present invention can be used in vehicle emission testing and other emission sensing systems and processes. A method and system for measuring hydrocarbon content in a gas sample measures individual hydrocarbon concentrations in the gas sample and determines a total concentration based on the individual concentrations. The total concentration is validated and/or scaled by determining whether water interference may be occurring and either adjusting the total concentration or flagging the total concentration as invalid. The total concentration may also be adjusted to account for ambient conditions, such as temperature, pressure or relative humidity, as well as for potential double-counting of individual hydrocarbon species.