STATEMENT OF THE MANUFACTURERS OF EMISSION CONTROLS ASSOCIATION ON THE ENVIRONMENTAL PROTECTION AGENCY'S PROPOSAL: GREENHOUSE GAS EMISSIONS STANDARDS AND FUEL EFFICIENCY STANDARDS FOR MEDIUM- AND HEAVY-DUTY ENGINES AND VEffiCLESPBASE2 

### August 18,2015
Good afternoon, I am Dr. Rasto Brezny, the Deputy Dir ector of the Manufacturers of Em issio n Contro l s Association. MECA is pleased to provide comments in s upport of the U.S. EPA ' s proposed rulemaking to establish medium- and heavy -duty greenhouse gas emiss ion standard s and corporate average fue l economy standard s for mode l years 20 1 8 and beyond.
MECA is a non-profit association ofthe world's l ead ing manufacturers of emission control technology for mobile sources. S ince the li st of regulated pollutants ha s been broadened to include C0 2, the portfolio of products offered by our members ha s also expanded beyond exhaust catalysts and filters to inc lude technologies that impact combustion effic iency and improve the overall C0 2 emissions of the powertrain.
We will s ubmit detailed written comments, however, today I wo uld like to focus on a few spec ific aspects ofEPA's Phase 2 proposal:
l

. MECA strongly s upport s the continued use of separate engine and vehicl e standard s. Th is framework, estab li s hed under the Phase 1 heavy-duty standards , ensu re s the important testing linkage between engine criteria and greenhouse gas emissions , and ensures that manufacturers deliver durable , enforceable improvements to truck fuel efficiency.
2. MECA believes that cost effective technical so lution s will be available to allow for the faster 2024 implementation timeline included under Alternative 4 in EPA ' s proposal. Manufacturers need this regulatory clarity to continue to make investments in technologies that will deliver the target reduction s. 3. MECA supports EPA ' s proposal to lower the cap on N20 em issions by 50%

. This tighter N 2 0 cap at 50 mglbhp-hr will be challenging in th e expected future of lower exhaust temperatures associated with improved engine efficiencies but manufacturers ha ve a numb er of technical opportunities avai lable to them to keep N2 0 emissions at low level s , including improved catalyst formulations , ammonia s lip catalysts with high se lectivity for nitrogen formation, and efficient urea dosing strategies.

4. MECA s upport s EPA ' s proposal to close th e curre nt e mi ssio n s loophole on truck glider kits

. It ' s time to in sure that all new trucks utilize the clean diesel engine options that have been availab le s inc e 2010. MECA asks EPA to cons ider an earl i er impl e me nt atio n date for thi s glider truck provision in stead of waiting until 20 1 8.5. MECA believes that PM emissio ns from auxiliary power units should be contro ll ed through the application of proven diesel particulate filter technology. There are already examples of sma ll off-road diesel engines engineered with filter so lutions that include active regeneration. EPA should follow California 's lead and implement policies so that APU e n gi ne s can benefit from the use of cost effectiv e filter so lutions.
Finall y, MECA believes that further reductions in NOx emissions from new heavy-duty on-road diesel engines , beyond the 20 10 highway requirements, will be possible through the combination of advanced diesel engines and evo lutionary improve ments to the existing suite of diesel exhaust emissio n control technologies. Clean diesel emission technologies and calibrations have evo lved and matured since EPA finalized their heavy-duty 2007-20 10 emission standards nearly 15 years ago. The current technologies will continue to advance by including high cell density , lo w thermal mass s ub strates, improved SCR catalysts coated directly on particulate filters , and next generation oxidation catalysts that include low temperature passive NOx adsorber capabilities. The application ofSCR technology on diesel engines has allowed eng in e manufacturers to optimize for both low NOx emissions and impro ved fuel efficiency and we believe that these optimizations can continue in the future to further reduc e both C02 and NOx em issions.
Advanced diesel emissio n control technologies are currently being evaluated in a California- sponsored test program to demonstrate the ability to meet a 0.02 g/bhp-hr NOx standard without n egatively impacting C02 emissions. T he diesel emiss ion co ntrol technologi es being demonstrated in this program are focused on delivering NOx reductions during the cold transient portion of the test cycle and on impro ving NOx emissions performance in low temperature duty-cycle operations. These technologies w ill in tum facilitate the r eduction of C02 emissions from vehicle s by extending the calibration window available to optimize combustion effic ienc y over lower temperatures.
Furthermore, reduced NOx emiss ions from heavy-duty e ngines wi ll provide important cost-effective reductions for regions ofthe country with current and future ozone non-attainment issues. A MECA spo n sored modeling study, using MOVES2014 , estimated the NOx reduction benefits of a national 0.02 g/b hp-hr federal heavy-duty NOx standard. When fully implemented , such a program wou ld deliver 266,000 tons per year or 730 tons per day ofNOx reductions ac ro ss the 47 contiguous states outside of California

. MECA asks EPA to initiate a rulemaking that will further r educe NOx emissions from heavyduty engi nes as soon as possible to allow the industry to develop fully optimized future engines that deliver improved fuel efficiency and ultra-low NOx emiss ions.

CONTACT: Rasto Brezny, Deputy Director MECA, E -mail: rbrezny @ meca
.org

2