Robert L. Greco, III

Group Director: Downstream and Industry Operations

1220 L Street, NW

Washington, DC 20005-4070

USA

Telephone 202-682-8167

Fax 202-682-8051

Email greco@api.org

www.api.org

October 24, 2013

Air and Radiation Docket and Information Center 

Environmental Protection Agency 

Mailcode 2822T 

1200 Pennsylvania Avenue, NW. 

Washington, DC 20460 

Re: Docket ID No. EPA-HQ-OAR-2011-0135 

Supplemental Comments of the American Petroleum Institute on the U.S. Environmental Protection Agency’s 

Proposed Rule on Control of Air Pollution from Motor Vehicles: Tier 3 Motor Vehicle Emission and Fuel 

Standards 

Submitted via email to a-and-r-docket@epa.gov

The American Petroleum Institute (API) recently became aware that the Manufacturers of Emission Controls 

Association (MECA) submitted “supplemental” comments to the EPA Tier 3 Rulemaking Docket that were critical 

of comments which we had filed jointly with the American Fuel and Petrochemical Manufacturers (AFPM) on 

June 28, 2013 concerning the Tier 3 Notice of Proposed Rulemaking (NPRM).1 Specifically, MECA stated that the 

intent of its submittal was:

“...to provide additional information and comments on four important topics: 1) the importance of 10 

ppm average sulfur gasoline to meeting proposed Tier 3 emission limits; 2) the synergy between ultralow sulfur gasoline and the introduction of cost effective, lean-burn, gasoline direct injection technology 

with improved fuel consumption; 3) costs associated with Tier 3 compliance on gasoline light-duty 

vehicles; and 4) harmonization with ARB’s 1 mg/mile LEV III PM standard.” 

In this submittal, MECA attempts to rebut the API/AFPM written comments concerning: (a) EPA’s 

inadequate justification of a technical need for a 10 ppm gasoline S standard, and (b) the future market 

penetration prospects for lean-burn GDI technology in the US light-duty vehicle fleet. 

The supplemental comments from MECA are based upon very limited data that have not been 

independently validated and that were generated using test fuels with potentially confounded properties. In 

addition, MECA’s outlook for lean-burn GDI technology in the US ignores the real-world experience of this 

technology in the European and Japanese markets where 10 ppm gasoline sulfur regulations have been in place. 

Our detailed response regarding each of these topics is further elucidated below.

 

1

Docket ID No. EPA-HQ-OAR-2011-0135
Page 2

Technical Need

MECA completely misses the point which API and AFPM were attempting to make with respect to the use of 

emission control technologies with lower sulfur sensitivity to reduce cold-start emissions in order to comply with 

the proposed Tier 3 standards. MECA asserts that API and AFPM “...assume that the use of three cold start 

emission control technologies [hydrocarbon adsorbers, reduced thermal mass substrates and exhaust piping, 

and secondary air injection] ...could be used to completely eliminate cold-start emissions with today’s gasoline 

sulfur levels.” This assertion takes the API and AFPM comments completely out of context. If one were to read 

our comments in their entirety, one would note that we never stated that these three technologies had zero 

sulfur sensitivity, nor did we assume that they would be used to completely eliminate cold start emissions with 

today’s gasoline sulfur levels. Rather, we noted that cold-start technologies “are not likely to be very sulfur 

sensitive” and that “... if manufacturers could completely eliminate cold-start emissions, the current level of 

catalyst technology would allow compliance with the Tier 3 standards” primarily because “warmed-up emissions 

are already at a level that is compatible with the standard.” A full rendition of our comments on this point 

follows (from p. 20 of our detailed comment submittal):

“The three technologies listed above are designed to reduce or eliminate emissions that occur during the 

early period of operation, when the engine is cold and the catalyst has not yet reached operating 

temperature. If these technologies are employed to provide the bulk of the reduction necessary, then clearly 

the need for sulfur reduction is lessened. Unfortunately, it appears EPA did not consider or even discuss this 

possibility. These listed technologies are exclusive of changes in engine design that EPA expects could and 

would be made to achieve compliance, and which are also not sensitive to gasoline sulfur levels.

Figure 2 shows that if manufacturers could completely eliminate cold-start emissions, the current level of 

catalyst technology would allow compliance with the Tier 3 standards. Furthermore, given that cold-start 

emissions and cold-start emission control technologies are not likely to be very sulfur sensitive, little or no 

reduction in gasoline sulfur content should be required to achieve compliance. While it is unlikely to be able 

to eliminate this source of emissions fully, the table clearly shows that warmed-up emissions are already at a 

level that is compatible with the standard, which again calls into question the need for additional reduction 

in gasoline sulfur content and EPA’s arbitrary selection of the proposed 10 ppm limit. Regardless, it is clear 

that EPA should have identified the possible emission control steps that are sulfur sensitive and those that 

are not sulfur sensitive, and evaluated whether 10 ppm sulfur was necessary and cost effective.”

MECA relies heavily on an SAE paper authored by Ball, Clark and Moser (Umicore)2in attempting to rebut 

our argument that there are sulfur-insensitive automotive technologies available today that could be used to 

facilitate compliance with the proposed Tier 3 emissions standards without the need to reduce average gasoline 

sulfur content to 10 ppm. This SAE paper had reported measurements of the FTP NOx emissions response of a 

2009 model year Chevy Malibu PZEV to test gasolines with sulfur contents of 3 ppm and 33 ppm. 

In reply to MECA, we reiterate concerns which API and AFPM had raised in a critique of the Umicore SAE 

paper provided in our June 28, 2013 written comments on the Tier 3 NPRM and also in an earlier November 11, 

2011 API response to the AAM proposal to cap gasoline sulfur content at 10 ppm. Specifically:

 The SAE paper fails to note the differences in the underlying properties of the base fuel used and how this 

may confound the results. Specifically, when comparing a CARB Phase II certification fuel (33 ppm sulfur) 

with a EEE-Lube certification gasoline fuel (“zero sulfur”), differences in distillation properties, chemical 

 

2

Ball, D., Clark, D., and Moser, D., "Effects of Fuel Sulfur on FTP NOx Emissions from a PZEV 4 Cylinder Application," SAE Technical Paper 2011-01-

0300, 2011, doi:10.4271/2011-01-0300. Note that the MECA Supplemental comments include an incorrect (2013) date citation to the SAE 

publication number for this paper.
Page 3

composition and oxygenates can impact emissions results. The standard industry practice is to use sulfur 

dopants to avoid underlying base fuel changes impacting the emissions.

 Results from testing two fuels on a single vehicle do not provide much guidance on the potential impact of 

fuel sulfur levels on the fleet of future Tier 3 vehicles. In particular, the Umicore paper did not provide a 

statistical analysis to show whether the measurements made on the single vehicle tested were (a) 

statistically significant and/or (b) broadly characteristic of the underlying technology represented.

Market Penetration of Lean-Burn GDI Technology

MECA asserts that lean NOx adsorber catalysts are the preferred strategy for reducing NOx on lean GDI lightduty engines and claims that 10 ppm sulfur gasoline is necessary for the use of this technology in the U.S. 

However, MECA does not explain why lean-burn GDI technology failed to enter the European and Japanese 

markets in significant volumes after these two regions adopted 10 ppm gasoline sulfur standards. (i.e., market 

penetration of lean-burn GDI peaked at ~2% and has since been declining.) MECA also alludes to two European 

OEMs who want to introduce this technology into the US market. Given the relatively low US gasoline light-duty 

vehicle market penetration by European OEMs, combined with the relatively high incremental cost of this 

technology, MECA’s comments do not contradict an analysis performed by the Martec Group3 which estimates 

that the market opportunity for lean-burn GDI is limited to at most ~3% by 2020.

We further note that the Agency agreed with Martec’s evaluation of lean-burn GDI technology in its 

regulatory impact assessment conducted for the final rulemaking, “2017 and Later Model Year Light-Duty 

Vehicle Greenhouse Gas Emissions and Corporate Average Fuel Economy Standards.” Specifically, the EPA did 

not use lean-burn GDI in the vehicle technology packages that were evaluated for that rulemaking as it was

found less cost effective than other available technologies. In short, the Agency agreed with API’s comments on 

this issue.4

In summary, the supplemental comments from MECA are based upon very limited data that have not been 

independently validated and that were generated using test fuels with potentially confounded properties. In 

addition, MECA’s outlook for lean-burn GDI technology in the US ignores the real-world experience of this 

technology in the European and Japanese markets where 10 ppm gasoline sulfur regulations have been in place. 

Please contact David Lax at (202) 682-8479 if you have any questions concerning the above submittal.

Sincerely,

Robert L. Greco, III 

 

 

3 McMahon, K.B., Selecman, C., Botzem, F., and Stablein, B., “Lean GDI Technology Forecast: The Impact of Ultra-Low 

Sulfur Gasoline Standards,” Society of Automotive Engineers Technical Paper Series, Paper No. 2011-01-1226, 2011

4

See: 2017 and Later Model Year Light-Duty Vehicle Greenhouse Gas Emissions and Corporate Average Fuel Economy 

Standards: EPA Response to Comments, EPA-420-R-12-017, August 2012), p. 12-32, available here