DAAAC Consortia Currently Being Re-evaluated
The genesis of the DAAAC Consortium was the EPA Final Rule for Emissions Durability Test Procedures, published in December of 2005 [ LINK ]. It applies to the certification procedures required to sell vehicles in the U.S. The rule provides a Standard Bench Cycle (SBC) for accelerated aging of emissions system components. The SBC can be used in place of the Standard Road Cycle (SRC) that requires vehicles to be driven for 120,000 miles, with periodic emissions measurements. Using the SBC offers significant savings in both time and expense to achieve the certification requirements. However, it cannot be used for diesel-fueled vehicles. Hence, all such vehicles must currently perform the full 120,000 mile SRC procedure. Based on input from industry, there was a strong desire to have a similar Diesel Aftertreatment Accelerated Aging Cycle (DAAAC) for diesel emissions components.
On February 22, 2008, SwRI hosted the DAAAC symposium in San Antonio, TX. Fifty nine people from thirty four companies and organizations attended the Symposium (Attendees List). The Symposium reviewed some of the existing understanding of diesel aftertreatment system aging mechanisms and aging methods. The shared information and discussions provided insight to begin the challenge of developing a standard bench cycle for diesel aftertreatment systems.
At the Symposium, Southwest Research Institute offered a proposal for an industry consortium to develop DAAAC aging procedures. As a result of the feedback on the initial proposal, SwRI prepared a revised proposal, which is available on request (Consortium Proposal). The Consortium has two primary objectives:
1) To develop a DAAAC that can be considered by EPA for inclusion in the vehicle certification regulations
2) To develop accelerated aging procedures for heavy duty diesel emission system components that can be used generically, apart from any regulated procedures
The two-year program is roughly divided into two parts:
Year 1: Generic single component aging investigations
Year 2: Light-duty and heavy-duty emissions system aging investigations
The work in Year 1 will concentrate on accelerated aging parameters relevant to light-duty, medium-duty and heavy-duty applications. The work in Year 2 is split into the two primary objectives:
Objective 1: Development of DAAAC procedures for use in vehicle certification
Objective 2: Development of DAAAC procedures for emission system component aging targeted at heavy-duty applications