AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
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Diesel Exhaust Particle Number Measurement and Measurement Variability Using Off-Highway Test Cycles
KIRBY J BAUMGARD, Nicholas J Barsic, John Deere Power Systems
Abstract Number: 447 Working Group: Combustion
Abstract Tailpipe particle number (PN) emission limits for European heavy-duty diesel engines have been introduced as part of the off-highway Stage V regulations. The regulations state that PN must be measured from either an approved partial flow dilution system or a full flow dilution system [EU 2016/1628]. This paper investigates: 1) ideal particle sampling probe location for the Sierra BG3 partial flow dilution system, 2) compares steady-state PN measurements for both CVS and BG3 systems, and 3) compares NRTC, non-road transient test cycle, and RMC, ramped modal cycle, data between CVS and BG3 systems.
The initial sample probe location was immediately downstream of the BG3 mini-dilution tunnel. PN results suggested that particles were not fully mixed at that location so the probe was moved downstream after the cyclonic separator. PN diluted by the BG3 and measured after the cyclonic separator resulted in good agreement with PN measured in the exhaust pipe with a second APC.
To compare the particle number emissions from the BG3 system to the CVS system, an exhaust sample was diluted with the BG3, passed through the cyclonic separator and then sampled with APC #1. Simultaneously, a second APC sampled from the CVS dilution system. A total of 133 data points were measured with and without a DPF and therefore, the PN concentration range varied from 1x10E10 to 1x10E14 #/cm3. Using a Pierson’s correlation analysis, the BG3 PN values were typically within 2% of the CVS values.
Repeated NRTC and RMC tests indicated that CVS and BG3 system %COVs were less than 1.5% and 7.5%, respectively. PN Comparisons between the CVS and BG3 for the NRTC and RMC cycles were typically within 10%. These values were measured without exhaust aftertreatment.