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DIESEL EXHAUST STANDARD
(PHASES 1-3)
CRC Project No.
AVFL-10a/b/c
Leaders: S. W. Jorgensen
K. J. Wright
Scope and Objective
The objective of this project is to identify the engine-out exhaust
composition of modern diesel engines from existing sources and to identify gaps
in the existing database so that a diesel exhaust standard can be developed for
simplified aftertreatment research evaluations.
Current Status and Future Program
Diesel exhaust aftertreatment is an important and
difficult process. With frequently cool exhaust temperatures (relative to
gasoline powered SI engines), and higher engine-out loadings of NOx
and PM, diesel exhaust conversion cannot be accomplished using standard gasoline
aftertreatment technology. The recent literature shows that bench level catalyst
testing is often done with a single hydrocarbon component (propene is a common
choice). There is a need for a more representative diesel exhaust standard.
This project is a three-phase project. Phase 1
(AVFL-10a) was a literature review. Phase 2 (AVFL-10b) builds on Phase 1 to fill
in gaps in the data on modern LD diesel exhaust speciation and propose a mixture
that might serve as the standard. Phase 3 (AVFL-10c) developed and demonstrated
a standard diesel exhaust mixture for broad research applications.
Contractors for Phases 1, 2, and 3 were selected
through competitive solicitations. The program objectives were:
1.
Overall program objective: Develop a reproducible standard mixture that
suitably captures the nature of actual diesel exhaust.
a.
A non-particulate, stable, mixture of pure compounds that includes major
species in appropriate proportions found in the exhaust of a wide variety of
diesel engines at various loads.
b.
A fuel and an associated method of preparation, which will generate an
exhaust and particle stream that represents the major conversion challenges in a
variety of diesel engines.
2.
Phase 1 specific objectives:
a.
Review and integrate the available international literature detailing the
speciated exhaust (gas and/or particulates) from diesel engines on an engine-out
basis.
b.
Define what experimental data are needed to allow informed definition of
a diesel exhaust standard mixture for use in after-treatment testing.
3.
Phase 2 specific objectives:
a.
Collect data on LD engine-out emissions to supplement Phase 1.
b.
Select a recipe for creating a diesel exhaust standard.
4.
Phase 3 specific objectives (either or both):
a.
Prepare a bottled non-particulate, stable mixture of pure compounds that
includes major species in appropriate proportions found in the exhaust of a wide
variety of at least LD diesel engines at various loads.
b.
Prepare a fuel, and an associated method of preparation, which will
generate an exhaust and particle stream that represents the major conversion
challenges in at least LD diesel engines.
The Phase 1 Final Report by SwRI and the associated committee summary (AVFL-10a)
have been published and posted on the CRC website (March 2004). The AVFL-10b
Final Report, released in August 2005, is posted on the CRC website.
In a related effort, ORNL was selected by the committee to collect and organize
existing data on diesel exhaust composition generated during "off-cycle"
operation such as rich combustion events or separate addition of reductants in
the exhaust stream. These techniques are being explored by catalyst and engine
manufacturers for regeneration, reduction or other methods for enhanced catalyst
performance. The Final Report on Project AVFL-10b-2 was published and is posted
on the CRC website (January 2005).
SwRI was selected to perform Phase 3. This project is complete, and a draft
final report is in review by the AVFL Committee.
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