May 21, 2008 — Southwest Research Institute® (SwRI®) will launch a cooperative research program this June to develop accelerated aging procedures for diesel emission systems and components. The effort will seek to provide common procedures for use by industry in general, and to potentially simplify certification procedures required to sell diesel-powered vehicles in the United States.
The consortium, Diesel Aftertreatment Accelerated Aging Cycles (DAAAC), intends to develop standard accelerated aging procedures for diesel emission systems for use in the same way as those the Environmental Protection Agency (EPA) has adopted for gasoline vehicles. Currently, the EPA requires diesel vehicle manufacturers to drive vehicles for 120,000 miles with periodic emissions measurements to certify the vehicles for sale. Gasoline vehicle manufacturers, however, can replace actual driving with an accelerated aging procedure (the standard bench cycle), providing for significant savings in both time and expense to meet certification requirements.
"If there are good accelerated aging procedures available, the EPA should be willing to consider writing them into the regulations," said Dr. Gordon Bartley, principal scientist in the Engine and Vehicle Research and Development Department in SwRI's Engine, Emissions and Vehicle Research Division. "Through this consortium, we will develop the procedures with technical input from industry- industry shares the cost - and at the end of the day, there will be standard procedures available to the members that all can agree on."
SwRI hosted a symposium in February to discuss the technical issues and obtain industry input in planning the formal consortium. Representatives from 35 companies and organizations attended and agreed that the consortium should work to develop procedures that can be considered for the vehicle certification regulations by the EPA. They also recommended developing procedures for heavy-duty diesel emission components and systems that can be used generically apart from any regulated procedures. In the first year of the two-year consortium, members will work on single-component aging procedures to identify the simplest effective procedures. During the second year, members will develop procedures for vehicle certification and for heavy-duty emission system applications.
"Developing acceptable procedures will be a complex process," Bartley said, adding that at least four different aftertreatment systems must be considered: the diesel oxidation catalyst (DOC), the diesel particulate filter (DPF), the lean NOx trap (LNT) or NOx adsorption catalyst (NAC), and the urea (ammonia) selective catalytic reduction catalyst (SCR).
"Given the many system configuration possibilities, it's not going to be easy to develop a single DAAAC procedure that covers them all," Bartley said. "But if we develop aging procedures for each of the possible aftertreatment devices, we may then be able to combine them into a single, modularized aging protocol that can be adapted to any given mix of devices and configurations."
Members will have access to all information developed during the consortium activities. They will also be able to use the developed procedures, whether or not they are published and written into the regulations. The advantage of membership is that the impact of the yearly contribution is multiplied by the number of participants, providing substantially more pre-competitive research and development than would be possible through similar funding from a single entity.
The DAAAC consortium kick-off meeting is scheduled June 13, at Southwest Research Institute, San Antonio.