SwRI Engineers Initiate Clean Diesel III Consortium, Develop Novel EGR System to Reduce NOx and PM
24 May 2000
SwRI Engineers Initiate Clean Diesel III Consortium, Develop Novel EGR System to Reduce NOx and PM
SAN ANTONIO--May 24, 2000--A consortium organized by engineers at Southwest Research Institute (SwRI) is developing low emission strategies that diesel engine manufacturers can put into production to improve air quality and meet stringent regulations.The four-year, $5.9 million Clean Diesel III program is composed of 18 participating engine manufacturers, component suppliers and petroleum companies from eight countries. The program builds on eight years of successful clean diesel consortia at SwRI.
"Our goals are ambitious -- to reduce emissions by 90 percent over the next four years," says Program Manager Daniel W. Dickey, a director in SwRI's Engine and Vehicle Research Division. Specifically, the consortium anticipates reducing emissions to 0.5 grams per horsepower-hour for oxides of nitrogen (NOx) and to 0.01 g/hp-hr for particulate matter (PM).
The diesel engine is the most efficient internal combustion engine. Its reputation for durability is excellent, but it produces NOx and PM emissions that can be harmful to the environment. A three-way catalyst, such as used on gasoline engines, isn't available to reduce those emissions on diesels.
"NOx emissions have already been reduced by a factor of five," says Dickey. "Despite this, an increase in the number of diesel vehicles on the road has caused emissions to actually rise over the last 10 years."
The consortium members select the areas of investigation and, as such, have opted to pursue five technologies that show promise for reducing diesel engine emissions. One of the most successful has been "water + exhaust gas recirculation (EGR)."
In traditional EGR, a portion of the exhaust is routed back to the intake manifold, helping to reduce the combustion flame temperature, which in turn lowers NOx emissions. SwRI recently developed and patented an EGR valve that is being considered by commercial clients to meet 2002 regulations.
NOx emissions are easily reduced with EGR technology; however, PM emissions increase during the process. Because the PM emitted by diesels is a suspected carcinogen, it is of serious concern. Several researchers are looking at the use of exotic fuels, such as dimethyl ether, to help reduce the occurrence of PM in various EGR schemes. SwRI's approach uses water, a much more readily available liquid.
The addition of water to the EGR process serves two functions. It acts as a diluent to reduce peak flame temperature and thus reduce NOx. The water also tends to boil before the fuel, breaking up the fuel particles and reducing particulates. A unique metering system developed by SwRI and Delphi mixes the water with diesel before injecting it into the engine.
SwRI tested the water + EGR system on an engine under laboratory conditions. Results showed that it greatly reduced NOx and effectively counteracted the production of particulates.
Other technologies being researched by the consortium include a novel direct-injection homogeneous charge compression ignition system, model-based engine controls, variable valve actuation systems and medium-duty gasoline engines. Additional projects will be addressed following completion of these tasks.
Editors: See www.swri.org/press/cd3.htm for pictures that dramatically illustrate the reduction of particulate emissions using the SwRI water + EGR system.
SwRI is an independent, nonprofit, applied research and development
organization based in San Antonio, Texas, with more than 2,700
employees and an annual research volume of more than $300 million.
Clean Diesel III reduces NOx and PM -----------------------------------
Fact Sheet
-- Clean Diesel III is a follow-on program to SwRI's highly
successful Clean Heavy-Duty Diesel Engine (CHDDE) I and II
programs, which began in 1991 and 1995, respectively.
-- There are current 18 members of the Clean Diesel III
consortium. U.S. participants include Caterpillar Inc.;
Delphi Diesel Systems; EMITEC Inc.; Jacobs Vehicle
Equipment Co.; Mack Trucks Inc./Renault Vehicules
Industriels; Cummins Engine Co.; Detroit Diesel Corp.;
Honeywell Turbocharging Systems; John Deere PEC; Eaton
Corp.; and Pure Energy Co. Overseas participants include
Isuzu Motors Advanced Engineering Center Ltd., Japan;
IVECO Motorenforschung AG, Switzerland; PSA Peugeot
Citroen, France; Volvo Truck Corp., Sweden; DAF Trucks,
N.V., Netherlands; Hyundai Motors Ltd., Korea; and
Komatsu Ltd., Japan.
-- The cost to participate in Clean Diesel III is $95,000,
per year for engine manufacturers and $55,000 per year for
component suppliers and fuel and oil companies. Several
new members are in the process of joining the consortium.
Contact Dickey at 210/522-3657 or ddickey@swri.org.
Southwest Research Institute and SwRI are official trademarks of Southwest Research Institute.