MEMORANDUM

FROM: Aron Butler

Assessment and Standards Division US EPA Office of Transportation and Air Quality

TO: Tier 3 Docket EPA

- HQ

- OAR

- 2011

- 0135

DATE: April 29 , 2013

SUBJECT : Data Collected in EPAct Fuel Effects Study Pilot Phases

Background

Section 1506 of the Energy Policy Act of 2005 require d EPA to produce an updated fuel effects model representing the current (at that time) light

- duty gasoline fleet, including determination of emission impacts of increased renewable fuel use. The resulting data collection activities came to be known as the EPAct test programs.

Prior to beginning emission measurements for the main statistically

- optimized matrix of 27 test fuels (also referred to as EPAct Phase 3 or EPAct/V2/E

- 89), EPA wished to perform a pilot study looking at impacts of ethanol blends on a representative fleet of Tier 2 vehicles

. This pilot work would also serve as a check

- out of procedural, analytical, and reporting requirements that the contractor (Southwest Research Inst itute) should meet before moving on to the much larger Phase 3 program

. 1

Goals and Design

This pilot testing consisted of emission measurements on the LA92 cycle for each of three fuels on each of 19 test vehicles. The fuels were a non

- ethanol base fuel, a10% ethanol blend, and a 15% ethanol blend (also referred to by their program designations 17, 18, and 19, respectively). The fuel propertie s were intended to approximate what typical market fuels of those types did or would look like, and the vehicles were to be representative of high sales makes and models. Table 1 shows test fuel properties and Table 2 the test vehicle models and engine configurations

. More detailed description of vehicle fleet selection is available in the E PAct/V2/E

- 89 testing report. 2

1 S ee report number EPA

- 420

- R

- 13

- 002, “ Assessing the Effect of Five Gasoline Properties on Exhaust Emissions from Light

- Duty Vehicles cert ified to Tier

- 2 Standards ”, available in the Tier 3 Docket EPA

- HQ

- OAR

- 2011

- 0135

, or on the web at http://www.epa.gov/otaq/models/moves/epact.htm

.Table 1. EPAct Phase 1

- 2 Test Fuel Properties

.

Property Unit Method Test Fuel 17 (E0) 18 (E10) 19 (E15)
Ethanol vol% D5599 <0.10 9.37 14.57
T50 ° F D86 215.3 211.8 202.4
T90 ° F D86 322.0 319.3 313.6
RVP psi D5191 9.20 9.08 9.05
Aromatics vol% D1319 29.1 23.1 22.0
Olefins vol% D1319 6.6 7.4 6.5
Benzene vol% D3606 0.55 0.55 0.45 Sulfur mg/kg D2699 23 23 20
RON

- D2699 93.1 93.7 93.6 MON

- D2700 83.5 85.1 84.4 (R+M)/2

- C alc. 88.3 89.4 89.0

Table 2. EPAct Phase 1

- 2 Test Vehicle Summary

.

Procedures

For Phase 1, the testing was performed at a nominal temperature of 75 ° F and for Phase 2 at 50 ° F. Fuels were tested in order of ascending ethanol content in each of Phases 1 and 2, with replicates on the same fuel being performed back

- to

- back. A summary of fuel change and prep proceduresis shown in Table 3. All fuel

- vehicle combinations were tes ted twice , with a third replicate being

performed in cases where the variability c riteria shown in Table 4 were exceeded

.

Table 3

. Summary of Fuel Change, Prep, and Test Procedures.
Step Description

1 Drain vehicle fuel completely via fuel rail whenever possible

2 Turn vehicle ignition to RUN position for 30 seconds to allow controls to allow fuel level reading to stabilize. Confirm the return of fuel gauge reading to zero

3 Fill fuel tank to 40% with next test fuel in sequence. Fill

- up fuel must be at the temperature of the next LA92 test (75 or 50 o F)

4 Start vehicle and execute catalyst sulfur removal procedure described in Appendix C of CRC E

- 60 Program report

5 Drain fuel and refill to 40% with test fuel. Fill

- up fuel must be at the temperature of the next LA92 test (75 or 50 o F)

6 Start vehicle and drive one LA4 cycle. Allow vehicle to idle in park for 2 minutes before engine shut

- down

7 Move vehicle to soak area without starting or driving

8 Park vehicle in soak area at proper temperature (75 or 50 o F) for 12

- 36 hours

9 Move vehicle to test area without starting engine

10 Perform LA92 cycle emissions test

11 Park vehicle in soak area of proper temperature for 12

- 36 hours

12 Move vehicle to test area without driving

13 Perform LA92 emiss ions test

14 Determine whether third replicate is necessary, based on data variability criteria (see Table 4 below)

15 If a third replicate is required, repeat steps 10, 11 and 12

16 If third replicate is not required, return to step 1 and proceed with next fuel in test sequence

Table 4

. Variability Criteria for T riplicate T esting

. Dilute Gaseous Emission Criteria for requiring a third test

(composite cycle emissions)

CO 2 Ratio of higher / lower > 1.04 NOx Ratio of higher / lower > 1.81 NMHC Ratio of higher / lower > 1.67Pollutants reported at the bag level included THC, CH 4 , CO, CO 2 , NO x , NMHC, and particulate

mass. Modal (second by second) tailpipe measurements were also collected for several gaseous pollutants. Results comparing NMHC and NOx emissions between the 0% and 10% ethanol fuels are available in an earlier memo to the RFS2 docket. 2

Exhaust speciation of alcohols, carbonyls, and C 2 - C 12 hydrocarbons was performed for bag 1 of all tests, plus bags 2

- 3 for all tests on the following subset of three vehicles: Silverado, Civic, Sienna.

Following the completion of Phase 2, emissions data were collected over the FTP cycle for a subset of six vehicles (Accord, Altima, Camry, Caravan, Focus, Silve rado) on the three pilot fuels . Fuels were tested in descending order of ethanol content. Alcohol, carbonyl, and hydrocarbon speciation was performed in bag 1. This data was intended to enable comparison of the Phase 1

- 2 results with historical datasets collected over the FTP.

During review of exhaust speciation results being collected during Phase 1, high proportions of some blendstock components (e.g., cyclohexane) were noticed for the E0 and E10

. This was suggestive that the fuel blender may have used higher proportions of specific compounds relative to typical commercial gasoline, and this was verified with subsequent fuel analyses . While this was not optimal

, and suggested fuel blending would need to be more highly specified in later program pha ses, pilot testing was completed using the available fuels

.

T he intent had originally been to fold the data from pilot fuels (17, 18, 19) into the Phase 3 dataset when producing the final emission models. However, we later decided against it for a numb er of reasons related to improvements made in vehicle handling and prep procedures (e.g., fuel carryover and fuel trim learning) between Phase s 1 and 3, as well as the concerns related to fuel blending highlighted above.

Data collection activities for the se pilot phases occurred between April 2008 and January 2009.

Availability of Data

A summary database file containing fuel, vehicle, and emission data for Phases 1, 2 and FTP testing is available in the docket as an Excel file with name “EPAct Pilot data summary April 2013. xlsx ”.

As described in a separate report, speciation profiles based on data from this program were developed and included in EPA’s SPEC IATE database for emission source profiles

. 3

2 See document number EPA

- HQ

- OAR

- 2005

- 0161

- 3157 in docket EPA

- HQ

- OAR

- 2005

- 0161.
3 S ee report number EPA

- 420

- R

- 09

- 002, “ Exhaust Emission Profiles for EPA SPECIATE Database: Energy Policy Act (EPAct) Low

- Level Ethanol Fuel Blends and Tier 2 Light

- Duty Vehicles ”, available in the Tier 3 Docket EPA

HQ

- OAR

- 2011

- 0135

.