Speciation of Nitrogen Oxides in a Light Duty Diesel Engine During an EGR System Failure Horiba Automotive Test Systems Corporation

Format:

Conference/Event

Author/Creator:

Nevius, Nevius, author.

Contributor:

Rooney, Richard

Zummer, Robert

Conference Name:

SAE 2012 World Congress & Exhibition (2012-04-24 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2012

Summary:

A 2.5-liter light-duty diesel van certified to Euro 4 emissionstandards was tested in a chassis dynamometer test cell, whichincluded a modal FTIR exhaust gas analyzer with the capability ofmeasuring 22 separate gas species. The engine was equipped with acooled Exhaust Gas Recirculation (EGR) system, which controls thenitrogen oxide emissions (NOx) to less than the 390 mg/km limitrequired by Euro 4 regulations. The vehicle was tested bydynamometer with the New European Drive Cycle (NEDC) sequence, andfound to exceed the 390 mg/km NOx limit. The FTIR was applied as adiagnostic tool for the engine EGR function.The FTIR monitored N₂O, NO, NO₂, and NH₃ over the NEDC testcycles. The linear-control EGR valve failed abruptly during asubsequent test, and the relative concentration of the reduced andoxidized nitrogen species showed significant changes. The nitrousoxide increase in concentration preceded the increase in NO and NO₂by several seconds, which suggests the EGR system failure couldgenerate both reducing and oxidizing conditions in the LDD engine.The increase in nitrous oxide emission is interesting because it istypically an insignificant fraction of the total nitrogen massemissions, so more nitrous oxide emitted during EGR failure isunexpected. Nitrous oxide is also of interest because it is apriority greenhouse gas that has recently been considered forregulation.After the EGR system was repaired, tests yielded NOx emissionsnear the 390 mg/km limit. The modal gas concentrations of thenitrogen species are shown during the EGR failure, and after theEGR repair, which resulted in low NOx and N₂O concentrations. Thisdemonstrated the FTIR analyzer was capable of diagnosing EGRproblems, and it demonstrated the value of monitoring unexpectedexhaust components when an engine has failing emission controlcomponents, poisoned catalysts, or any unconventional emissionproblem

Notes:

Vendor supplied data

Publisher Number:

2012-01-0876

Access Restriction:

Restricted for use by site license