UNITED STATES ENVIRONMENTAL PROTECTION AGENCY 

NATIONAL VEHI CLE AND FUEL EMI SSIONS LABORATORY 

2565 PLYMOUTH ROAD 

ANN ARBOR, MICHIGAN 48105&2498 

MEMORANDUM AuglN8,2013 

OFFICE OF 

AIR AND RADIATION 

SUBJECT: EPA, Alliance, a nd G loba l Automakers Meetin g on Issues Re lated to 

T ier 3 Cert Fue l and the CAFE "R" Factor 

FROM: Glenn W. Passavant, Office of Transportation and Air Quality 

TO: Public Docket EPA-HQ-OAR-2011 -0 135 

In response to a request from the Alliance of Automobile Manufacturers (Alliance) and the 

Association of Global Auto makers (GA) EPA met with representatives of these groups in 

Ann Arbor to follow-up on their comments on the Tier 3 NPRM (July 1, 20 13) related to 

the "R" factor. The meeting was held on August 7, 2013. A list of attendees is attached. 

EPA provided the attached presentation. It laid out a concept developed by EPA staff 

(near term option) which could potentially create a regulatory construct which would allow 

for manufacturers to continue CAFE testing on Indolene (EO) while conducting emissions 

testing on a different certification fuel. If adopted, this concept would stay in place at least 

until EPA took a final action on an "R" value change (assuming EPA changes certification 

fuel specifications in Tier 3). The presentation also provided a background on the issue 

related to the value for the "R" factor itself and updated EPA's analysis based on 

information recently received from Oak Ridge National Laboratory. There was a lively 

and constructive exchange on both topics. EPA asked the Alliance/GA to provide us input 

and feedback on the potential near term concept. Both EPA and the manufacturers agreed 

to conduct further analysis of the data used in the "R" factor analysis including the effect 

of potential other changes to Tier 3 certifi cation fuel. 
M~{t k~ ol~q~ . : Yo.T}, F( t . .. \~Je.:.:. . 

, uJ ~.U Ot .,;-. R '-l , Y\. <\ 

l ~~ ~ ..vJ~ h- ' :"""I .J. M _ , _, \( ·~ ·~

·! GredrcZ.: ~ A-M~r_oav..:f:O 

_: &-r~ _':" rE-N fPJ!_ AJ f:!i7 

-------- .(Y't4fsf-v--_ tJrY:t lf: 

_ .. -----·-·· .j Uavi'd!. ~~ i )i..r _· . ,, 

_. -;-Je._ ~ y I C,J;;:l,. (0 

-· '~- .i\.vV'.i u ~ li 

1- k 

-- ·· ·· f~~Ael~ 

. - ~ ~ S----u...kz.. 

fVI A-H-N6ub ~1 ft-sS t.rle 

. DO;vA LD tJAG'I 

I 

:-::3 bc_PiAC h 

.! 

' e c;,:... 

. . -o~ ...... ,.s ~ct ~q k t?. t)a .... ,..., ·~.J.:J.LS ) ~ ):1 ' • 7i'l"'it 

J ~~~ ['e__ ~~~ ~~d ~ Jf!./~~~ ce. 

&t-:1 . (1.4 /f. 

E-61 

VVJ 

( ( V\N{l1 6. () ~ 

~~ 

ef?A- 1 ~ Cf;:t _ 

C h r:.Z:S /-4' 

61"'] 

Cla-w.6,ro.z~ +.;;@. C4k&..c.N<.c< cr ... (., : ~i ~~~ "'-·-d ~-"~~t:f.' e~~· C.C '::' _ ' 

/l ~o...w-q.@_~~~ctC\.~~ ~ C.O U\_ 

L(Jv ~) i-,~. de~:-'~ It\ (t). ~(hJ. ~~ ' 

)e. nn ~ Slj _.e-{lco @ Vw ~t:r} 

tA ti~ ~ ~ ~~~ .t <0 f¥1 

-to~\-~'{-C..~~ @.~~ 4M~.c~ 

Yh ,- ~/)'\. ~ "'w"' ~ e/'?4~:J of/ 

S: ·(:c J_ ~i:;~['!; 'J~ 

d<rn ..tJ ??") J &. J'"' , e 0771 

-::Ib 1.-0 v t c.. \-:\- ~ 'FVR. D • co tvJ 
Fuel Economy R-Factor: 

Discussion of ORNL Program and 

Overall R-Factor Value 

EPA-Alliance-Global· Automakers 

R-Factor Discussion 

August 7, 2013 

U.S. EPA Presentation 

U.S. EPA- Staff Draft Only - Do Not Quote 

or Cite- For Discussion Purposes On ly 
Overview 

• Regulatory and Interim Options to Address R-Factor 

• Historic and Recent R-Factor Estimates 

• Alliance Re-Analysis of EPAct Study 

• EPA Response to Alliance Re-Analysis of EPAct Study 

• Overview of ORNL Study 

• EPA Review of Recent ORNL Study 

• Overview and Analysis of All R-Factor Estimates 

• Summary 

08/07/2013 U.S. EPA - Staff Draft Only - Do Not Quote 

or Cite - For Discussion Purposes Only 

2 
Regulatory and Interim Options to Address R-Factor: 

R-Factor in The Preamble to the Tier 3 NPRM 

• The T3 NPRM contained text concerning the effects of a potential 

certification test fuel changes on C02, CAFE and labeling and the 

. need to address these programs. 

• The T3 NPRM also acknowledged the "R" factor issue, but indicated 

that it was not directly or fully a certification test fuel change issue. 

- The docket included an EPA memo entitled "Analysis of the Effects of 

Changing Fuel Properties on the EPA Fuel Economy Equation and RFactor". 

• The T3 NPRM indicated that if action were ultimately taken to 

change the "R" factor it would be done in a later action. 

- No specific value was discussed in the Preamble or regulations. 

- No timing for a future action was indicated. 

• Regs written to address long term goal that FE/C02 will at some 

point be based on EXX and not EO cert fuel. 

08/07/2013 U.S. EPA - Staff Draft Only- Do Not Quote 

or Cite - For Discussion Purposes Only 3 
Regulatory and Interim Options to Address R-Factor: 

Near Term Process 

• It is clear that manufacturers want EPA to take immediate action on the Rfactor. 

- Make a change in the Tier 3 FRM. 

- Adjust the "R" factor value upward to 1. 

• We cannot act on 11R" factor in Tier 3. 

- Notice/comment issues 

- Coordination with NHTSA 

• Staff is working a plan which would permit use of indolene (EO) for 

CAFE/GHG testing (assuming we change cert fuel to EXX) until R factor is 

addressed. 

- Adjust proposed reg text related to fuel use requirements for various tests. 

- Address test burden related to using different fuels 

- Resolve timing for future action. 

• Attempt to reach technical consensus on R factor value. 

08/07/2013 U.S. EPA- Staff Draft Only - Do Not Quote 

or Cite - For Discussion Purposes Only 

4 
Regulatory and Interim Options to Address R-Factor: 

Potentia/Interim Changes for Emission Testing on EXX 

(until an EPA "Rn factor action is completed) 

• Allow FE and GHG testing (done as a set) on EO even if criteria 

pollutant emission testing is on EXX. 

- Revise proposed §86.113-04(2)(i)(B) and §86.113-077(a)(l)). 

• Expand §86.113-07(a)(S) such that during transition period, it only 

requires vehicles to pass criteria pollutants on the emissions cert 

fuel (EXX) even if it uses EO for FE testing. 

- AECD/Defeat Device policy still applies 

• Only need to do EDV on EXX for criteria pollutants; not required to 

use this value in FE as is currently done. 

- Should use EO data from dual testing on EDV for fuel economy 

08/07/2013 U.S. EPA - Staff Draft Only- Do Not Quote 

or Cite- For Discussion Purposes Only 

5 
Regulatory and Interim Options to Address R-Factor: 

Potentia/Interim Changes for Emission Testing on EXX 

(until an EPA URN factor action is completed) · 

• Litmus on EXX for labeling tests, but also allow the 

use of EO. 

- Manufacturer calculations only; not submitted/included 

in EPA database (Verify) due to R-Factor concerns on EXX 

- SG/CWF/NHV calculation method for EXX to be provided 

in guidance letter 

• Same fuels used for certification must be used on 

IUVP for criteria pollutants and GHG. 

08/ 07/2013 U.S. EPA- Staff Draft Only- Do Not Quote 

or Cite- For Discussion Purposes Only 

6 
Historic and Recent R-Factor Estimates 

Below is a table showing all the R-Factor estimates that have 

currently been proposed and generated based on actual test 

programs. 

1983 

1987 

1993 

2013 

08/07/2013 

0.866-0.93 

(EPA} 

0.6 

(GM/Ford) 

0.93 

(Auto/Oil Study) 

0.86 (EPAct E0-10} 

0.93 (EPAct all data) 

0.94 (V4 dataset) 

U.S. EPA- Staff Draft Only- Do Not Quote 

or Cite- For Discussion Purposes Only 

1.0 

(Mfr. Preference) 

7 
Alliance Re-Analysis of EPAct Study 

• Alliance pointed out a possible outlier/ 

erroneous heating value reported by SwRI for 

EPAct fuel 25 {E20) that was used in EPA's 

initial R-factor analyses 

• Alliance re-analyzed data ·without this suspect 

fuel and arrived at R = 0.96 

-Cited as supp.orting R-factor value of 1.0 

08/07/2013 U.S. EPA- Staff Draft Only- Do Not Quote 

or Cite- For Discussion Purposes Only 

8 
EPA Response to Alliance 

Re-Analysis of EPAct Study 

• In June, EPA updated its EPAct Study R-factor calculations to 

use round-robin heating values instead of SwRI values in 

emission test data files (compare slides 10 & 11) 

• For the ElO analysis, some results for individual vehicles 

moved around slightly, but the weighted test fleet average 

(0.86) did not change from the docket memo 

• For the E20 analysis, results shifted substantially higher for 

most vehicles, moving the average from 0.82 to 0.93 

- According to a t-test, R-factor for E20 vs. EO group is now significantly 

different from the ElO vs. EO group 

08/ 07/2013 

U.S. EPA- Staff Draft Only- Do Not Quote 

or Cite -For Discussion Purposes Only 9 
1.1 

EPAct Phase 3 Fuel Economy R-values by vehicle 

1 

0.9 I ..._, I 

0.8 I '- Y I '- e i' l _......-- , ......_.. I J/T I J • 

0.7 

ElO avg = 0.86 

E20 avg = 0. 82 

0.6 +----------------------------- +-------------------------------

0.5 +-----------------------------------------------------------------

-+-wtd ElO vs EO 

---wtd E20 vs EO 

Results based on EO & E20 fuel groups 

0.4 +---~--~---r--~--~---,-- r---.---~--~--~-- ---r--~----

CCOB CIMP CSIL DCAL FlSO FEXP FFOC HCIV HODY JLIB NAL T SOUT TCAM TCOR TSIE 

This chart shows the R-factor calculated from the weighted dataset as in the previous slideJ then adds a line for 

E20. A t-test suggests there is no difference between the two sets of values. 

ORIGINAL PLOT FROM DOCKET MEMOJ MARCH 2013 

08/07/2013 

U.S. EPA- Staff Draft Only- Do Not Quote 

.or Cite- For Discussion Purposes Only 10 
1.1 

EPAct Phase 3 Fuel Economy R-values by Vehicle 

1.0 I • • fi • • I\ 

o.9 I • e '\ I I \\ I I \ - I ~._ ""- ~ \ 

0.8 I • \ I \ I ~ ~ ~ 

0.7 

0.6 

0.5 

0.4 

ElO avg = 0.86 

E20 avg = 0.93 

Results based on EO & E20 fuel groups 

CCOB CIMP CSIL DCAL FlSO FEXP FFOC HCIV HODY JLIB NALT SOUT TCAM TCOR TSIE 

...,_ ElOwtd 

---E20wtd 

This chart shows the R-factor calculated from the weighted dataset as in the previous slide, then adds a line for 

E20. A t-test suggests there is a difference between the two sets of values. 

PLOT UPDATED WITH ROUND ROBIN HEATING VALUES, JUNE 2013 

08/07/2013 U.S. EPA - Staff Draft Only - Do Not Quote 

or Cite- For Discussion Purposes Only 11 
EPA Response to Alliance 

Re-Analys.is of EPAct Study 

• EPA also updated its analysis to include a linear 

regression of MPG on heating value for each vehicle 

- Slope of this line can be used to calculate R-factor for all or 

a subset of fuels and vehicles 

- This is the method the Alliance suggested and has been 

used in the past 

• Results are very similar to the fuel grouping method 

previously used (see slide 13) 

08/07/2013 U.S. EPA - Staff Draft Only - Do Not Quote 

or Cite - For Discussion Purposes Only 

12 
1.1 

1.0 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

EPAct Phase 3 Fuel Economy R-Values by Vehicle 

i 

22 ·.---------------------------------------

EPAct Phase 3 Impala 

21 I • -~ • ~ 

~ - - v. 0.0002x+ 0.8823 

R'=0.909 

19+-------.-------.-------.-------.-------, 105000 107500 110000 112500 115000 117500 

Net Hell inc Value, Btu/col 

E0-10 avg = 0.84 

All fue ls avg = 0.92 

Results based on slope of line through all tests on f uels listed 

CCOB CIMP CSJL DCAL Fl SO FEXP FFOC HCIV HODY JLIB NAL T SOUT TCAM TCOR TSJE 

~ EO-ElO only 

-11-AII fuels 

This chart shows the R-factor calculated by the slope method. First a linear regression is made for FE versus heating value for each 

vehicle, then the high and low heating values are used to calculate predicted FE values. Those FE and heating values are then used 

in the standard R-factor equation. The inset plot is an example of the slope fit for the Impala, where the red dots are E20 fuels. 

08/07/2013 U.S. EPA- Staff Draft Only- Do Not Quote 

or Cite- For Discussion Purposes Only 

13 
Overview of ORNL R-factor Analysis 

• Used DOE V4 dataset 

- V4 study was commissioned by DOE in 2007 to examine emission controls 

durability of vehicles operating on mid-level ethanol blends 

• 18 vehicle models tested with 4 different ethanol levels 

{EO/E10/E15/E20) 

- 59 vehicles tested total, covering PCs and LOTs MY 2002-2009 

• 5 models tested on all four ethanol levels 

• 13 models tested on three ethanol levels (ElO omitted) 

- Replicate testing was performed for each ethanol level 

• Emission measurements were taken prior to, in the middle of, and 

at the end of full useful life aging on an assigned blend 

• R-Factor Results: 0.94 {+/-) 0.04 for full data set 

- 0.96 (+/-) 0.04 if one vehicle with questionable results is omitted from the 

dataset (2007 Honda Accord) 

08/07/2013 U.S. EPA - Staff Draft Only - Do Not Quote 

or Cite - For Discussion Purposes Only 

14 
EPA Review of ORNL R-Factor Analysis 

• EPA reviewed the ORNL report and talked with one of 

the authors, focusing on suitability of the data for Rfactor analysis 

• Identified some sources of uncertainty and key design 

differences relative to the EPAct study: 

- Potential influence of fuel tank carryover during fuel 

changes 

- Uncertainty in fuel heating value measurements 

- Potential influence of test cycle (FTP vs. LA92) 

- Imbalance of ElO certification fuel test results vs ElS and 

E20 fuel test results 

- Omission of questionable results for 2007 Honda Accord 

- Each of these is discussed more in the following slides 

08/ 07/2013 U.S. EPA - Staff Draft Only - Do Not Quote 

or Cite - For Discussion Purposes Only 15 
EPA Review of ORNL R-Factor Analysis: 

Potential influence of fuel tank carryover 

• Fuel carryover would make NHVs closer together for 

different test fuels, which could influence resulting 

R-factor 

• The ORNL program used a sequence of two 

drain/fills for all vehicles when changing test fuels 

• EPAct investigated carryover, and used three 

drain/fills on most vehicles, including several 

models that were also used by ORNL 

08/07/2013 

U.S. EPA - Staff Draft Only- Do Not Quote 

or Cite - For Discussion Purposes Only 16 
EPA Review of ORNL R-Factor Analysis: 

Uncertainty in fuel heating value measurements 

• NHV has a first order impact on R-factor calculations 

• ORNL adjusted the measured heating values for 

some TRC test fuels based on engineering judgement 

• While this may have been justified, it highlights the 

fact that· the V4 fuel properties were based on single 

measurements 

• EPAct NHV values resulted from multiple 

measurements from a round robin process 

08/07/2013 

U.S. EPA- Staff Draft Only- Do Not Quote 

or Cite - For Discussion Purposes Only 17 
EPA Review of ORNL R-Factor Analysis: 

Potential influence of test cycle (FTP vs. LA92} 

• No large datasets varying test cycle as a control 

parameter 

• Expect primarily two factors may influence R-value: 

cold operation and aggressive driving 

- Both are transient modes representing relatively 

low-efficiency operation 

• LA92 cycle contains higher speeds and accel rates 

than FTP, and its composite result weights cold 

operation more than FTP 

- May explain difference in results seen here 

08/07/ 2013 U.S. EPA- Staff Draft Only - Do Not Quote 

or Cite- For Discussion Purposes Only 

18 
EPA Review of ORNL R-Factor A_nalysis: 

Imbalance of E10 certification fuel test results versus 

E15 and E20 fuel test results 

• The ORNL R-factor analysis had 31 E10 and 216 E15+E20 

• In contrast, EPAct had 295 E10 t~sts and 312 E15+E20 tests. 

- As a result, EPAct has nearly lOx as many ElO observations, and 

one third more for the mid-level blends. 

- In total, EPAct had about 50% more tests (930 vs about 600). 

• Calibration differences near the limits of fuel trim likely 

create more variability in the E20 results 

- R-factor is very sensitive to fuel economy measurement 

08/07/2013 U.S. EPA - Staff Draft Only- Do Not Quote 

or Cite- For Discussion Purposes Only 

19 
EPA Review of ORNL R-Factor Analysis: 

Removal of questionable fuel economy results 

• OR·NL removed the results for the 2007 Honda Accord 

since the "FTP fuel economy results showed 

unexpected variability that resulted in R factors that 

were deemed to be illogical and unrepeatable~" 

although no single issue with the vehicle was 

established. 

• EPAct dataset had some vehicles with R-values <0.8 · 

• Difficult to defend on a statistical basis (see next slide) 

08/07/2013 U.S. EPA - Staff Draft Only - Do Not Quote 

or Cite - For Discussion Purposes Only 20 
... 

s 

u 

"' ~ 

1.60 

1.40 

ex: 1.20 ~ 'iii 

8. 

g 1.00 

u 

"'C 

CIJ 

... 

.s: 

.!!» 0.80 

~ Q. 

..... 

~ 0.60 

0.40 

EPA Review of ORNL R-Factor Analysis: 

Removal of questionable fuel economy results 

Values are average values per vehide for 

all fuels and all test intervals for the V4 

program. Error bars are 95% confidence 

intervals for each vehid e . 

!..?:, ~"' to (&~ $' ~ . to ~,0 ~., ~ -1\.<. ~"' fb <,~ ~"' {7 !..'& ~ c..O ~ ~ ~ (§> ~~ ~ ~'I> §- _,~ (}~ ~0 0~ ~'\- ~'I> ~- ~'l$ ~<'"-

~~c.; 9>~ ~<7 d !o() Q.;§ ~(,0 ~e 9>""'1> ~0 ~0, ..e~o ~+q r:S>" ro'~ ~"''I> .c..v ~ 

'),rS> ,...,<§5 ,..,~ # '),~ r§>"" rSl"' ~ ') '),<§5 '),~ ~ "~ #' ~ ,..,~ ,.._rS> ,..rS>~ ,.,§lO; 

08/07/2013 

~ ~ ~,..,~ "~ "" 

Figure 2. Average R factor for each vehicle model. 

Source: ORNL Report #ORNL/TM-2013/198, pg_ 9 

U-S. EPA - Staff Draft Only - Do Not Quot e 

or Cite- For Discussion Purposes Only 

21 
EPA Review of ORNL R-Factor Analysis 

• Bottom line: 

- Both EPAct and ORNL analyses leave questions about 

accuracy and relevance of resulting R-values 

• EPAct has a larger dataset across the ethanol blend levels, so 

expect a more precise R-factor estimate 

• EPAct was also designed as a fuel effects study with . 

attention to key details like fuel carryover and fuel analysis 

• V4 data is on the FTP cycle, which may be expected to 

produce different results from LA92 

- Reasonable to consider both in a quantitative analysis 

08/07/2013 

U.S. EPA - Staff Draft Only - Do Not Quote 

or Cite - For Discussion Purposes Only 

22 
Summary 

• Focusing on more recent studies, EPA's current 

thinking is that available data would support an Rfactor value of 0.9 

08/07/2013 

R-Factor Values from Data 

0.6 GM 1985 study 

0.933 EPA 1987 Rule theoretical calculation 

0.866 EPA 1987 Rule theoretical calculation (discounted) 

0.93 19 

0.86 EPAct Study (EO~ElO data) 

0.92 EPA re-analysis of EPAct Study (all fuels) 

0.94 ORNL V4 dataset 

0.96 ORNL V4-dataset with lowest vehicle omitted 

U.S. EPA- Staff Draft Only - Do Not Quote 

or Cite- For Discussion Purposes Only 23 
Summary 

• Determine best process and arena to revise R-factor 

- Tier 3: Not proposed! Only requested comment in 

preamble 

- EPAct R-Factor technical memo included in Tier 3 docket to 

spur comment, not to indicate regulatory direction/intent 

• Best course of action: Separate rulemaking to address 

this and any other fuel economy equation technical 

amendments 

• In the interim or future, we welcome any data from the 

OEMs that can add to or enhance the currentlyavailable, R-Factor dataset 

08/07/2013 

U.S. EPA- Staff Draft Only - Do Not Quote 

or Cite- For Discussion Purposes Only 24