Method and system for vehicle emission testing
AssigneeGordon-Darby Systems, Inc.
InventorsRobert J. Tefft, S. Jay Gordon, Clifton Mahaffey, Thomas C. Austin, Thomas R. Carlson
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Abstract
A method and system for vehicle emission testing measures pollutant concentration, but then provides for conversion of the measured pollutant concentration into its corresponding pollutant mass, thereby allowing for the calculation of a vehicle's emission test scores for one or more common pollutants in units of mass per distance. Through the use of the method and system of the present invention, significantly more accurate results can be obtained as compared to prior art test methods, and without the implementation, operating, and maintenance costs of comparable test methods.
Claims18
A method for determining a mass of a pollutant in an emissions sample obtained from a particular vehicle, comprising the steps of:
- extracting the emissions sample from the particular vehicle as it is operated over a testing period comprised of one or more discrete time intervals;
- determining instantaneous fuel consumption of the particular vehicle;
- calculating an exhaust flow rate based on the instantaneous fuel consumption of the particular vehicle at each discrete time interval;
- analyzing the emissions sample extracted from the particular vehicle to measure the concentration of the pollutant in said sample at each discrete time interval;
- and
- determining the mass of the pollutant at each discrete time interval by multiplying the exhaust flow rate by the measured concentration of the pollutant by a known density of the pollutant.
A method for determining a mass of a pollutant in an emissions sample obtained from a particular vehicle, comprising the steps of:
- measuring a velocity and an acceleration rate of the particular vehicle over a testing period comprised of one or more discrete time intervals;
- measuring a concentration of the pollutant in the emissions sample at each discrete time interval;
- calculating a total drive wheel power demand at each discrete time interval based on the velocity, the acceleration rate and certain physical characteristics of the particular vehicle:
- determining an engine load and an engine speed based on the total drive wheel power demand;
- determining instantaneous fuel consumption of the particular vehicle;
- calculating an exhaust flow rate based on the instantaneous fuel consumption of the particular vehicle at each discrete time interval;
- and
- converting measured pollutant concentration into pollutant mass at each discrete time interval by multiplying the exhaust flow rate by the measured concentration of the pollutant by a known density of the pollutant.
Dependencies are inferred from the claim text.