TIME RESOLVED NITRIC OXIDE MEASUREMENTS IN COMBUSTION EXHAUSTS

A RESEARCH AND DEVELOPMENT PROGRAM IS PLANNED THAT WOULD PRODUCE AN INSTRUMENT CAPABLE OF PROVIDING REAL TIME MEASUREMENTS OF NITRIC OXIDE (NO CONCENTRATIONS IN POWER PLANT OR INTERNAL COMBUSTION ENGINE EXHAUSTS. THIS INSTRUMENT WOULD BE CAPABLE OF MONITORING TRANSIENTS IN EMISSION WITH A RESOLUTION F 10 MS OR LESS. THIS APPROACH UTILIZES AN INEXPENSIVE, HIGH-RESOLUTION INSTRUMENT CONCEPT WHICH IS EASILY EXTENDABLE TO SPECIES OTHER THAN NO. THE MOTIVATION FOR THIS NEW CAPABILITY IS CLEAR. FEDERAL CLEAN-AIR INITIATIVES ARE PUSHING FUTURE EMISSIONS STANDARDS FOR NITROGEN OXIDS (NOX) TO EVER LOWER LEVELS. A REAL TIME, NON-EXTRACTIVE, NO MONITOR COULD BE USED AS THE SENSOR IN A FEEDBACK CONTROL LOOP; INFORMATION DERIVED FROM THIS MEASUREMENT SYSTEM WOULD ALLOW DIESEL ENGINE MANUFACTURERS TO CRITICALLY ASSESS THEIR ENGINES' POLLUTANT PERFORMANCE OVER THEIR ENTIRE OPERATING ENVELOPE. THE KEY TO THE TECHNICAL APPROACH IS TO MEASURE CONCENTRATIONS OF NO WITH ABSORPTION DIAGNOSTICS IN THE INFRARED AND PACKAGE THE INSTRUMENT IN A FASHION THAT FACILITATES ITS APPLICATION TO SEVERE ENVIRONMENTS. IN PHASE I CONCENTRATIONS OF NO WILL BE DERIVED FROM SINGLE LINE ABSORPTION MEASUREMENTS NEAR 5.2 MUM. THIS WAVELENGTH IS CHOSEN SPECIFICALLY TO AVOID SPECTROSCOPIC FEATURES FROM OTHER GASES TYPICAL OF COMBUSTION EXHAUSTS AND BE INSENSITIVE TO TYPICAL LOADINGS OF PARTICULATES IN THESE FLOWS.