New SAE Emissions Standard J2992 and the Promise of FTIR Spectroscopy

As EPA emissions standards for internal combustion have become stricter, engineers require tools that are capable of accurately detecting smaller and smaller concentrations of gaseous emissions. Examples include Carbon monoxide (CO), Carbon Dioxide (CO2), Oxides of Nitrogen (NO, NO2, N2O) ammonia (NH3) methane (CH4), and formaldehyde (H2CO). One technology that holds significant promise for the engine testing professional is Fourier Transform Infrared (FTIR) spectroscopy.

FTIRs already have a foothold in diesel engine test labs for use in of Selective Catalytic Reduction (SCR) development. FTIR is also a mature technology with a long track record in other industries – petro chemical, pharmaceutical, criminal investigation – to name a few. Given that some engine testing facilities already have access to an FTIR analyzer, the possibility of using an existing tool for testing a wider variety of gaseous constituents is very attractive.

What’s the catch? Well, currently EPA 1065, Engine Testing Procedures, does not have much to say about engine testing with FTIRs. Sure, there are a couple mentions in relation to N2O but these are very general (for example, “use appropriate analytical procedures…”) or point to other EPA test methods (EPT Test Method 320 in specific) which are quite cumbersome to read and aren’t written specifically for engine testing. In addition, many professionals in the engine testing field don’t have extensive experience with FTIR so it can be challenging to use this tool in a manner that both works for the user and keeps the EPA happy.

This is where the new SAE standard comes in. J2992, is written to provide specific practical guidance to test engineers who plan to use FTIR for gaseous engine emissions detection and analysis. It provides the “how” and “when” for testing to be EPA 1065 compliant. The end user can be confident in the Standard since it is written by industry professionals with FTIR experience and is based off 1065 practices for other gaseous analyzers. In addition, the SAE Emissions Standard Committee (ESC) didn’t write this document in a vacuum. The SAE ESC worked in close collaboration with the EPA during the development process to ensure that guidance given in the standard was sound and sensible.

Conclusion

FTIR is a robust and well understood instrument technology. By following the SAE standard, testing professionals can gain confidence in their results, making FTIR an invaluable tool in testing gaseous emissions levels for EPA compliance and certification.

Learn more about the J2992 standard