SAE 2014 Light Duty Emissions Control Symposium
Technical Session Schedule
Wednesday, December 10
(Session Code: LDD700)
Room Salon ABCD 3:00 p.m.
Moderators - Michael Andrew Smith, Chrysler Group LLC
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|Applying the DAAAC Protocol™ - Considerations for Light-Duty Diesel Applications
Accelerated aging of automotive gasoline emissions catalysts has been performed on bench engines for decades. The EPA regulations include an accelerated aging cycle called the Standard Bench Cycle (SBC) that is modeled on the RAT-A cycle developed by GM Corp. and published in 1988. However, this cycle cannot be used for diesel aftertreatment components because it is based on stoichiometric operation, whereas diesel engines typically operate under excess air (lean) conditions.
The necessity for accelerated aging cycles for diesel emissions systems can be illustrated by considering that the full useful life requirement in the United States for heavy-duty on-highway trucks is 435,000 miles, and off-road applications may be 8,000 hours. Aging under normal operating conditions is excessively time-consuming and expensive. This need was recognized, and the DAAAC Protocol™ developed to provide accelerated aging cycles for the vast majority of diesel emissions system applications. Although the DAAAC Protocol™ was developed for heavy-duty applications, there are no reasons not to utilize it for light-duty applications as well. However, there are distinct differences that should be taken into consideration.
This presentation will summarize the DAAAC Protocol™ and discuss some of the considerations for adaptation to light-duty applications.
Gordon J. Bartley, Southwest Research Institute
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|Durability of Light Duty Diesel and Gasoline Emission Control Systems
One of the most important aspects of meeting emission standards is catalyst robustness. Emissions must be met at high mileage, termed “full useful life”, which is 150,000 mi for light and medium duty vehicles under Tier3/LEV3. Catalyst durability is application and system specific. Full useful life aging and correlations to accelerated aging schemes typically include both hydrothermal exposure and chemical poisoning. Robustness tests are designed to exceed the limits of a particular catalyst or filter material and test to failure. New aging schemes and robustness tests are needed when new technologies such as cold start traps for HC and NOx, gasoline particle filters, and SCR coated filters are incorporated into conventional three-way and diesel exhaust systems. This presentation will include a summary of recent emission certifications and publications by various vehicle manufacturers, aging and robustness testing of conventional exhaust systems, as well as a look into the durability of future emission control technologies.
Christine K. Lambert, Ford Motor Co.