Journal Article
Recovery of Tail Pipe Species Concentrations and Its Effect on Emissions Calculations from Raw Exhaust Gas Streams during Chassis Dynamometer Tests
2016-04-05
2016-01-0984
This paper proposes a method to recover species concentrations at the tail pipe exit of heavy-duty vehicles during chassis dynamometer tests, and investigates its effect in the calculation of emissions from their raw exhaust streams. It was found that the method shown in this paper recovered the sharp peaks of the gas species. The effect on calculations was significant, as time-variant raw exhaust flow rate and emissions concentrations data are acquired continuously during a test (at 10 Hz), and their product is integrated during calculations. The response of the analyzer is delayed due to the time taken for transport of the sample gases from the probe tip to the analyzer, and deformed due to mixing and diffusion during this transport. This ‘convolution’ of the concentration data stream introduces an error in the final result, calculated in g/mile.
