26 November 1983 Tunable Diode Laser Measurements Of Carbon Monoxide In Engine Exhaust
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In the past few years we have made several studies of carbon monoxide (CO) in automotive exhaust with lead-salt tunable diode lasers. The laser system has several advantages over conventional exhaust analysis instrumentation including a fast response time (25 milliseconds) and the ability to measure CO in the presence of water vapor without interference. These studies were done using an engine dynamometer with a 5.7 ℓ V-8 engine. Initially, the CO was measured before and after the exhaust catalytic converter during step changes in the air-fuel ratio to study the dynamic response of the converter. The converter responded differently when the air-fuel ratio was switched from lean to rich than it did when switched from rich to lean. This behavior was attributed to chemical storage effects on the converter bed, among other factors. Next, the engine was closed-loop controlled at a given CO concentration level using the diode laser as a CO sensor rather than the conven-tional oxygen sensor. Limit cycle oscillations of the closed-loop system were substantially reduced by this method. Finally, a linearized model of the engine's CO emissions was developed based on the TDL measurements of CO during oscillation of the air-fuel ratio at different engine operating conditions.
© (1983) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Jeffrey A Sell, Jeffrey A Sell, } "Tunable Diode Laser Measurements Of Carbon Monoxide In Engine Exhaust", Proc. SPIE 0438, Tunable Diode Laser Development and Spectroscopy Applications, (26 November 1983); doi: 10.1117/12.937431; https://doi.org/10.1117/12.937431

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