Aerodyne Research, Inc.

Mark Stuart Zahniser

David D Nelson, Jr

Charles E Kolb

Paul L Kebabian

Scott Christopher Herndon

J Barry McManus

John Barry McManus

A non-contact, extractive sampling system and method is provided for measuring the exhaust gas composition and fine particle composition of exhaust emissions of various types of vehicles under actual operating conditions. A portion (or sample) of an exhaust plume of a vehicle is pulled or extracted through an extraction sampling tube, via a vacuum pump, to a remote trace gas detection system where the concentration of one or more constituents present in the sample of exhaust plume may be measured. In this regard, the invention enables vehicle emissions measurements to be made at a location remote from roadway, rather than using known, 'cross-path' remote emissions sensing systems.

Extractive sampling system and method for measuring one or more molecular species

A cross-road motor vehicle exhaust gas analyzer uses tunable infrared laser differential absorption spectroscopy incorporating photon infrared detection to determine the absolute fractional absorption of a laser by the gaseous medium. Spectroscopic constants of the gaseous species of interest are applied to the absolute fractional absorption to calculate the pertinent absolute column densities. In addition to a laser that sweeps across one or more absorption line of an component of interest, the system of the invention includes a laser source tunable over an absorption line of a reference species; the calculated column density of the reference species is used to normalize the concentration of the component of interest to the fuel consumption rate of the motor vehicle.

Laser system for cross-road measurement of motor vehicle exhaust gases

In a laser emitter-receiver system, a tunable diode laser provides a beam of coherent light having a selected frequency. An infrared detector spaced from the source detects the light transmitted along the beam path between the source and the detector and produces a corresponding output in response thereto. A heating laser provides radiation to the diode laser to heat, and thereby to change the frequency of, the latter laser. The radiation from the heating laser is varied periodically to modulate the intensity of the radiation incident on the diode laser thereby to frequency-modulate the diode laser output over a selected tuning range. A controller responsive to the detector output regulates the current to the diode laser to minimize selected frequency components of the modulated light beam from that laser so that the power output of the diode laser varies minimally when that laser is tuned over the selected tuning range.

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Lexington, MA, United States of America

Mark Stuart Zahniser