PR-179-13203-R01 Real Time Laser Sensor for Nitrogen Oxides and Carbon Monoxide

Performance of current NOx sensors is problematic, in particular drift and cross-sensitivity to other species. Many lean burn engines are operated based on earlier calibrations. Operators must allow for drift and use large margins to meet emissions. Laser sensors (based on absorption at target wavelengths) are self-calibrating and immune to interferences. In particular, recently developed Quantum Cascade Lasers (QCLs) allow measurements at mid-infrared (MIR) wavelengths thereby allowing stronger signals, better schemes to mitigate interferences, and fast time response. This project evaluated a commercial QCL-based NOx (NO, NO2) and CO sensor for use in gas engine applications. The project also developed and performed bench top testing of a custom sensor which uses a “pitch and catch” design.