This makes the challenging NO2 measurement possible with non-dispersive infrared sensors (NDIR) – especially in combination with the company’s differential pyros. Traditionally, the amount of NO2 in exhaust gases has been determined by UV or electrochemical methods. Engine development was the only field using laser-based IR process.

The concentration of carbon compounds has long been measured using NDIR. As a result different techniques were applied for each type of chemical compound.

Source: Control Engineering Europe - All Articles
More...