DIESEL EXHAUST STANDARD (PHASES 1-3)

CRC Project No. AVFL-10a/b/c

Leaders:    S. W. Jorgensen
                  K. J. Wright

Scope and Objective

Diesel exhaust aftertreatment is an important and difficult process. With frequently cool exhaust temperatures (relative to gasoline-powered spark-ignited 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.

The scope 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.

This project consisted of three phases.  Phase 1 (AVFL-10a) was a literature review. Phase 2 (AVFL-10b) built on Phase 1 with an experimental program 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. 

Detailed objectives:

Overall program objectives:

1. Develop a reproducible standard mixture that suitably captures the nature of actual diesel exhaust.
2. Develop 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.
3. Develop 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.

Phase 1 specific objectives:

1. Review and integrate the available international literature detailing the speciated exhaust (gas and/or particulates) from diesel engines on an engine-out basis.
2. Define what experimental data are needed to allow informed definition of a diesel exhaust standard mixture for use in after-treatment testing.

Phase 2 specific objectives:

1. Collect data on LD engine-out emissions to supplement Phase 1.
2. Select a recipe for creating a diesel exhaust standard.

Phase 3 specific objectives (either a or b; or both):

1. 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.
2. 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.

Current Status and Future Program

Contractors for Phases 1, 2, and 3 were selected through competitive solicitations.  SwRI was independently selected for each phase.

The Phase 1 Final Report and the associated committee summary (AVFL-10a) have been published and posted on the CRC website (March 2004).  The AVFL-10b Phase 2 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).

The Phase 3 project is complete, and the Final Report was released in June 2008.

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