Rapid In Situ Measurement of Fuel Dilution of Oil in a Diesel Engine using Laser-Induced Fluorescence Spectroscopy

2007 ◽  
Author(s):  
Jim Parks ◽  
Bill Partridge ◽  
Shawn Whitacre
Keyword(s):  
Diesel Engine ◽  
Fluorescence Spectroscopy ◽  
Laser Induced Fluorescence ◽  
In Situ Measurement ◽  
Fuel Dilution

scholarly journals CAFE: a new, improved nonresonant laser-induced fluorescence instrument for airborne in situ measurement of formaldehyde

2019 ◽  
Vol 12 (8) ◽  
pp. 4581-4590 ◽  
Author(s):  
Jason M. St. Clair ◽  
Andrew K. Swanson ◽  
Steven A. Bailey ◽  
Thomas F. Hanisco
Keyword(s):  
Curve Fitting ◽  
High Sensitivity ◽  
Laser Induced Fluorescence ◽  
Time Profile ◽  
In Situ Measurement ◽  
Quality Research ◽  
Research Aircraft ◽  
Operator Interaction ◽  
Nm Range

Abstract. NASA Compact Airborne Formaldehyde Experiment (CAFE) is a nonresonant laser-induced fluorescence instrument for airborne in situ measurement of formaldehyde (HCHO). The instrument is described here with highlighted improvements from the predecessor instrument, COmpact Formaldehyde FluorescencE Experiment (COFFEE). CAFE uses a 480 mW, 80 kHz laser at 355 nm to excite HCHO and detects the resulting fluorescence in the 420–550 nm range. The fluorescence is acquired at 5 ns resolution for 500 ns and the unique time profile of the HCHO fluorescence provides measurement selectivity. CAFE achieves a 1σ precision of 160 pptv (1 s) and 90 pptv (10 s) for [HCHO] = 0 pptv. The accuracy of CAFE, using its curve-fitting data processing, is estimated as ±20 % of [HCHO] + 100 pptv. CAFE has successfully flown on multiple aircraft platforms and is particularly well-suited to high-altitude research aircraft or small air quality research aircraft where high sensitivity is required but operator interaction and instrument payload is limited.

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