A smart and robust NOx emission evaluation tool for the environmental screening of heavy-duty vehicles
conference paper
At the request of the Dutch Ministry of Infrastructure and Environment a smart measurement system was developed to judge the real world NOx emission of heavy-duty vehicles. The measurement system uses a NOx - O2 sensor for the measurement of the tail pipe concentration of NOx and to estimate the tail pipe concentration of CO2 for diesel engines. A GPS measures the time-based vehicle speed profile over the test trip. Furthermore, a special data-evaluation method helps to reveal emission performance over the speed ranges of a vehicle. The method is based on collecting (binning) emissions of NOx and CO2 in speed intervals and calculates the CO2 specific NOx emissions for each interval. The measurement system proved to correlate well with PEMS, which can be seen as an accurate reference measurement. The method is less accurate than PEMS, but its merit to simply measure more and longer at lower costs increases the overall accuracy, because more of the often variable emission behaviour is captured. The method can be extended with more exhaust gas compounds like NH3 and CH4 and particulate matter once accurate sensors become available. The measurement system could fulfil several purposes, for instance as a screening tool for national emission surveillance programs, national approval schemes, in-service conformity checking and as tool to check emission requirements in the procurement of vehicle fleets.
TNO Identifier
573239
Source title
19th International Transport and Air Pollution Conference 2012, Thessaloniki, Greece, 26-27 November 2012
Collation
11 p.
Files
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