Open AccessVCSEL-based, high-speed, in situ TDLAS for in-cylinder water vapor measurements in IC engines
Author(s) -
Oliver Witzel,
Alexander Klein,
Christian Meffert,
Steven Wagner,
Sebastian Kaiser,
Christof Schulz,
Volker Ebert
Publication year - 2013
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.21.019951
Subject(s) - tunable diode laser absorption spectroscopy , vertical cavity surface emitting laser , optics , materials science , laser , tunable laser , calibration , diode , water vapor , semiconductor laser theory , absorption (acoustics) , optoelectronics , cylinder , noise (video) , physics , mechanical engineering , quantum mechanics , artificial intelligence , meteorology , computer science , image (mathematics) , engineering
We report the first application of a vertical-cavity surfaceemitting laser (VCSEL) for calibration- and sampling-free, high-speed, in situ H2O concentration measurements in IC engines using direct TDLAS (tunable diode laser absorption spectroscopy). Measurements were performed in a single-cylinder research engine operated under motored conditions with a time resolution down to 100 μs (i.e., 1.2 crank angle degrees at 2000 rpm). Signal-to-noise ratios (1σ) up to 29 were achieved, corresponding to a H2O precision of 0.046 vol.% H2O or 39 ppm · m. The modulation frequency dependence of the performance was investigated at different engine operating points in order to quantify the advantages of VCSEL against DFB lasers.