Fuel penalty from periodic rich combustion of a diesel fuelled engine during lean NOx trap purging
Compression ignition engines produce excessive NOX emissions compare to spark ignition engines. Lean NOX trap system is currently being investigated as an aftertreatment device to suppress the NOX emissions from compression ignition engines. The application of this aftertreatment device requires alt...
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| Main Authors: | , , |
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| Format: | Conference or Workshop Item |
| Published: |
2007
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| Subjects: | |
| Online Access: | http://eprints.uthm.edu.my/4155/ http://eprints.uthm.edu.my/4155/1/Ahmad_J._Alimin%2C.pdf |
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| Summary: | Compression ignition engines produce excessive
NOX emissions compare to spark ignition engines. Lean NOX
trap system is currently being investigated as an aftertreatment
device to suppress the NOX emissions from
compression ignition engines. The application of this aftertreatment
device requires alternating lean and rich exhaust gas
mixture, in order to produce the necessary reducing agents
necessary for purging the LNT system. In this study an engine
testbed was set-up which consisted of a 4-cylinder light-duty
diesel engine, a diesel oxidation catalyst (DOC) and an LNT
system. The LNT system purging utilised in-cylinder
enrichment method based on DSPACE system, which
controlled the engine management system (EMS) and the main
engine operating parameters. The enrichment method used
open-loop control system, to provide different storage/purge
cycles for the LNT system. During enrichment, extra fuelling
was needed to produce the required rich exhaust mixture.
Emissions test at low operating temperature using this method
had shown the capability of this in-cylinder enrichment
method to produce the required periodic rich exhaust mixture
for the LNT system. Nevertheless, the occurrences of periodic
rich combustion also led to the increase in fuel penalty.
Therefore, an acceptable trade-off between emissions
reduction and fuel penalty is necessary. |
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