A Noncryogenic Tunable Diode Laser Monitor for On-Road Vehicle EmissionsEPA Contract Number: 68D00270
Title: A Noncryogenic Tunable Diode Laser Monitor for On-Road Vehicle Emissions
Investigators: Nelson, David D.
Small Business: Aerodyne Research Inc.
EPA Contact: Richards, April
Project Period: September 1, 2000 through September 1, 2002
Project Amount: $224,899
RFA: Small Business Innovation Research (SBIR) - Phase II (2000) Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , SBIR - Monitoring , Small Business Innovation Research (SBIR)
Description:Remote sensing of on-road vehicle pollutant emissions is a powerful technique for evaluating real-world automotive and truck emissions. Thousands of vehicles are inspected by a single instrument during 1 day. Aerodyne Research, Inc., has previously demonstrated a laser spectrometer that remotely senses vehicle emissions with exquisite sensitivity and selectivity. This instrument used continuous wave lead sail diode lasers operated at cryogenic temperatures using a liquid nitrogen dewar. This use of cryogenic lasers increases the construction cost of the instrument, as well as its operating cost. The goal of this proposal is to build a noncryogenic instrument with similar capabilities that is more compact and less expensive.
During Phase I, Aerodyne proved that this can be done using quantum cascade QC lasers. The accomplishments included: (1) acquisition of a single mode QC laser operating near 965 cm-1; (2) demonstration of pulsed operation of this laser with pulse widths between 10 and 100 ns and repetition rates up to 200 kHz; (3) integration of this pulsed laser with Aerodyne's proprietary tunable diode laser data acquisition system; (4) acquisition of laboratory spectra of ethylene and ammonia using this system; (5) discovery of operating conditions producing light with a narrow spectral line width (0.012 cm-1); (6) integration of the QC laser with an open path optical system capable of making remote sensing measurements; and (7) remote sensing measurements of ammonia emissions from several automobiles driven through the sensor.
During Phase II, Aerodyne will design a dual QC laser system capable of detecting ammonia and carbon dioxide and, therefore, capable of making quantitative ammonia emissions measurements. This system will be compact, cryogen-free, and easily deployed. Aerodyne also will optimize the detection sensitivity and develop a scheme for measuring hydrocarbon emissions - a required element of all automotive inspection programs. The resulting instrument should retain the sensitivity of the existing instrument at a fraction of the cost, and without liquid nitrogen.
The market for a highly accurate, noncryogenic vehicle emissions monitor is large. It is believed that laser methodology will be widely implemented in state and federal emissions monitoring programs when the current research instrument is redesigned into a less expensive, more easily operated commercial version. Aerodyne has received repeated inquiries from several states encouraging the company to offer a portable, noncryogenic, inexpensive version of the highly successful (and recently patented) cryogenic remote sensing instrument. Aerodyne also is negotiating with companies that perform state inspection and maintenance programs.