Document ID: EPA-HQ-OAR-2010-0162-3612
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2011-08-29T04:00Z

UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                NATIONAL VEHICLE AND FUEL EMISSIONS LABORATORY
                             2000 TRAVERWOOD ROAD
                           ANN ARBOR, MI  48105-2498

									          	OFFICE OF
										AIR AND RADIATION

July 29, 2011

MEMORANDUM

SUBJECT:	Meeting with PACCAR

FROM:	Angela Cullen

TO:		Docket EPA-HQ-OAR-2010-0162

This memorandum documents a meeting held on May 3, 2011 between PACCAR and EPA.  

Paccar requested a meeting to discuss the tractor aerodynamic drag certification testing method.  In the NPRM, the agencies proposed that tractor manufacturers use a two part screening approach for determining the aerodynamic inputs to the GEM.  The first part of the proposed evaluation approach uses a bin structure characterizing the expected aerodynamic performance of tractors based on definable vehicle attributes.  The first part would require manufacturers to assign each vehicle aerodynamic configuration to one of five aerodynamic bins.  For each bin, EPA and NHTSA have already defined a nominal Cd. The five bins are "classic," which incorporate few if any aerodynamic features; "conventional" which represent the average new tractor sold today; "SmartWay" which have added components to reduce drag:  "Advanced SmartWay," which have underbody airflow treatments, down exhaust, and other features, and "Advanced SmartWay II which incorporates technologies that are still in the prototype stage such as advanced gap closing.  The second proposed evaluation uses aerodynamic testing.  Manufacturers would be required to compare their test results with the bin Cds. If their test data shows a better or worse result than the Cd assignment, they would be required to certify to the correct bin.  The agencies expressed an interested in working with the regulated industry to develop a primary test approach.  The agencies proposed to allow Cd assessments with vehicle coast down testing, wind tunnel testing, computational fluid dynamics, and constant speed tests combined with good engineering judgment.  There are two sub-categories for class 7 trucks: 1) low/mid roof day cabs; and 2) high roof day cabs.  There are five sub-categories for class 8 trucks: 1) low/mid roof day cabs; 2) high roof day cabs; 3) low roof sleeper cabs; 4) mid roof sleeper cabs; and 5) high roof sleeper cabs. 

Paccar asked that in addition to requests made by EMA/TMA to improve the aerodynamic drag coefficient test method and which are described in a memo to the docket several additional items be considered by the agencies in establishing the reference test method.   Paccar stated the proposed changes would improve repeatability and accuracy and reduce the test burden on regulated entities.  They requested the following:
         o Closed road for coast down testing;  
         o Standardized trailer gap at the centerline of the vehicle; 
         o Specified height of the trailer at front and back; 
         o Specified tractor tires (including mileage and other important parameters);
         o The agencies identify and define parameters that have not been defined (such as data smoothing, frequency of calculation, etc.); 
         o Recommend limiting grade to 0.1% (vs. 0.5% currently) because the gravitational effect of a 68,000 pound vehicle is a large contributing factor to low speed road load.