UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

NATIONAL VEHICLE AND FUEL EMISSIONS LABORATORY

2000 TRAVERWOOD DRIVE

ANN ARBOR, MI 48105-2498

 OFFICE OF

AIR AND RADIATION

October 23, 2012

MEMORANDUM

SUBJECT: Alliance of Automobile Manufacturers Submittal of Recommended Technical 

Corrections for the “2017 and Later Model Year Light-duty Vehicle Greenhouse 

Gas Emissions and Corporate Average Fuel Economy Standards” Final Rule

FROM: Christopher Lieske, Environmental Engineer

TO: EPA Docket # EPA-HQ-OAR-2010-0799

On September 17, 2012, Julie Becker of the Alliance of Automobile Manufacturers sent EPA a 

list of recommended technical corrections to the EPA regulations for the final rule “2017 and 

Later Model Year Light-duty Vehicle Greenhouse Gas Emissions and Corporate Average Fuel 

Economy Standards.” The list of suggested technical corrections submitted by the Alliance is 

attached. The Alliance requested that EPA consider making the recommended corrections prior 

to the publication of the final rule in the Federal Register if possible. If it was not possible to 

make the corrections prior to publication, the Alliance suggested that EPA issue a postpublication technical correction.

Of the corrections suggested by the Alliance, there were three that corrected erroneous cross 

references in the regulations (directing the reader to incorrect sections), and in some cases to 

sections that were no longer in the regulations (items 3, 4, and 21 of the attached). Because the 

corrections to the cross references do not affect the meaning of the regulations, the Office of the 

Federal Register was able to make the corrections prior to publication upon request from EPA. 

The corrections to the regulatory text are shown below. Other recommended technical 

corrections provided by the Alliance remain under consideration by EPA, and any additional 

corrections that are deemed necessary will be done through a separate action.

Corrections to References in EPA Regulatory Text

§86.1869-12(b)(2)(i): corrections to references in “Credits” definition, changing (d)(5) to (f) and 

(d)(1(i) to (b)(1).

(i) Determine the gram per mile decrease for the combined passenger automobile and light truck 

fleet using the following formula: 
Where:

Credits = The total of passenger automobile and light truck credits, in Megagrams, determined 

according to paragraph (d)(5)(f) of this section and limited to those credits accrued by using the 

default gram per mile values in paragraph (d)(1)(i)(b)(1) of this section.

ProdC = The number of passenger automobiles produced by the manufacturer and delivered for 

sale in the U.S.

ProdT = The number of light trucks produced by the manufacturer and delivered for sale in the 

U.S.

§86.1869-12(c)(1) and (2): corrections to references, changing §600.113–08 to §600.113–12

(1) Testing without the off-cycle technology installed and/or operating. Determine carbon-related 

exhaust emissions over the FTP, the HFET, the US06, the SC03, and the cold temperature FTP 

test procedures according to the test procedure provisions specified in 40 CFR part 600 subpart B 

and using the calculation procedures specified in §600.113–0812 of this chapter. Run each of 

these tests a minimum of three times without the off-cycle technology installed and operating 

and average the per phase (bag) results for each test procedure. Calculate the 5-cycle weighted 

city/highway combined carbon-related exhaust emissions from the averaged per phase results, 

where the 5-cycle city value is weighted 55% and the 5-cycle highway value is weighted 45%. 

The resulting combined city/highway value is the baseline 5-cycle carbon-related exhaust 

emission value for the vehicle. 

(2) Testing with the off-cycle technology installed and/or operating. Determine carbon-related 

exhaust emissions over the US06, the SC03, and the cold temperature FTP test procedures 

according to the test procedure provisions specified in 40 CFR part 600 subpart B and using the 

calculation procedures specified in §600.113–0812 of this chapter. Run each of these tests a 

minimum of three times with the off-cycle technology installed and operating and average the 

per phase (bag) results for each test procedure. Calculate the 5-cycle weighted city/highway 

combined carbon-related exhaust emissions from the averaged per phase results, where the 5-

cycle city value is weighted 55% and the 5-cycle highway value is weighted 45%. Use the 

averaged per phase results for the FTP and HFET determined in paragraph (c)(1) of this section 

for operation without the off-cycle technology in this calculation. The resulting combined 

city/highway value is the 5-cycle carbon-related exhaust emission value including the off-cycle 

benefit of the technology but excluding any benefit of the technology on the FTP and HFET.

86.1868-12(f)(1) and §86.1868-12(g)(1) both reference §86.167-14. However, that section does 

not exist. Correct reference is to §86.167-17.

(f) AC17 reporting requirements. Manufacturers may use the provisions of this paragraph (f) as 

an alternative to the use of the Air Conditioning Idle Test to demonstrate eligibility to generate 

air conditioning efficiency credits for the 2014 through 2016 model years. This paragraph (f) is 

required for the 2017 through 2019 model years. 

(1) The manufacturer shall perform the AC17 test specified in §86.167-1417 of this part on each 

unique air conditioning system design and vehicle platform combination for which the 

manufacturer intends to accrue air conditioning efficiency credits. The manufacturer must test at 
least one unique air conditioning system within each vehicle platform in a model year, unless all 

unique air conditioning systems within a vehicle platform have been previously tested. A unique 

air conditioning system design is a system with unique or substantially different component 

designs or types and/or system control strategies (e.g., fixed-displacement vs. variable 

displacement compressors, orifice tube vs. thermostatic expansion valve, single vs. dual 

evaporator, etc.). In the first year of such testing, the tested vehicle configuration shall be the 

highest production vehicle configuration within each platform. In subsequent model years the 

manufacturer must test other unique air conditioning systems within the vehicle platform, 

proceeding from the highest production untested system until all unique air conditioning systems 

within the platform have been tested, or until the vehicle platform experiences a major redesign. 

Whenever a new unique air conditioning system is tested, the highest production configuration 

using that system shall be the vehicle selected for testing. Air conditioning system designs 

which have similar cooling capacity, component types, and control strategies, yet differ in terms 

of compressor pulley ratios or condenser or evaporator surface areas will not be considered to be 

unique system designs. The test results from one unique system design may represent all variants 

of that design. Manufacturers must use good engineering judgment to identify the unique air 

conditioning system designs which will require AC17 testing in subsequent model years. Results 

must be reported separately for all four phases (two phases with air conditioning off and two 

phases with air conditioning on) of the test to the Environmental Protection Agency, and the 

results of the calculations required in §86.167 paragraphs (m) and (n) must also be reported. In 

each subsequent model year additional air conditioning system designs, if such systems exist, 

within a vehicle platform that is generating air conditioning credits must be tested using the 

AC17 procedure. When all unique air conditioning system designs within a platform have been 

tested, no additional testing is required within that platform, and credits may be carried over to 

subsequent model years until there is a significant change in the platform design, at which point 

a new sequence of testing must be initiated. No more than one vehicle from each creditgenerating platform is required to be tested in each model year.

(g) AC17 validation testing and reporting requirements. For the 2020 and later model years, 

manufacturers must validate air conditioning credits by using the AC17 Test Procedure 

according to the provisions of this paragraph (g). 

(1) For each air conditioning system selected by the manufacturer to generate air conditioning 

efficiency credits, the manufacturer shall perform the AC17 Air Conditioning Efficiency Test 

Procedure specified in §86.167-1417 of this part, according to the requirements of this paragraph 

(g).

Attachment
Alliance’s List of Technical Corrections on 2017-2025 GHG Regulations 

(Submitted to EPA on 9-17-2012)

No. Comment

1

Dual Fuel CAFE Credits: the final rule should reflect that CAFE credit for dual fuel vehicles is 

available for MY 2020 and later based on EPA quantification, as indicated on p. 1706 of the 

Preamble. The chart on p. 1935 should be updated to remove the 0.0 mpg “maximum increase” 

for 2020 model year and later. Also see p. 1981-1982, where the NHTSA requirement references 

the EPA section of the regulations, §600.510-12(c).

2

Definitions: The definitions of full size pickup truck, mild hybrid electric vehicle and strong hybrid 

electric vehicle were moved to the overall definition section of Subpart S in §86.1803-01 (pp. 

1810-1812). One concern is that those definitions could come into play for other unintended 

components of the regulation. We suggest moving them back to the specific section that 

discusses full size pickup truck credits, §86.1870-12, and that the NHTSA definitions for these

items in 523.2 (pp. 1944, 1947, and 1949) also be updated to reference §86.1870-12. This will 

help avoid confusion and assure that the rule does not inadvertently identify a new class of 

vehicles without first carefully considering any future use of these definitions.

3

§86.1869-12(b)(2)(i): “Credits” is defined as the total of PC/LT credits in Megagrams determined 

according to paragraph (d)(5) of this section. However, paragraph (d)(5) does not exist. We 

believe this was meant to refer to paragraph (f) of the section.

4

§86.1869-12(b)(2)(i): In the definition of the term “Credits” EPA refers to the “default gram per 

mile values in paragraph (d)(1)(i).” However, paragraph (d)(1)(i) is a single component of the data 

which must be provided when using an off-cycle technology demonstration program with 

alternative EPA-approved methodology. We believe this was meant to refer to paragraph (b)(1).

5

§86.1869(b)(3): Allows manufacturers to determine alternative credit values for the “table” 

technologies, but it is not clear whether the 10 g/mi cap still applies. The preamble suggests that 

it would not, but the location of this subparagraph (3) within the larger context of paragraph (b) 

may lead to confusion in the future.

6

§86.1869-12(b)(4)(iii): Definition of high efficiency exterior lighting includes backup/reverse lights, 

but no credit was specified at (b)(1)(ii) for this position.

7

§86.1869-12(c)(1) and (2) refer to calculation procedures specified in 600.113-08. Why not 

600.113-12?

8

2014-2016 Idle Test: The Alliance recommended widening the temperature (to 75 ±5 deg F on 

average and 75 ±10 deg F as an instantaneous) and humidity tolerances (to 50 ±10 grains/lb). 

Although EPA agreed with this comment, the final rule does not reflect the change. For the a/c 

idle test, §86.165-12(c)(2) requires 73-80 deg F average and 75±5 deg F instantaneous. This 

average temperature tolerance (73-80 deg F) is tighter than our current ambient test site limits of 

68-86 deg F where this testing will take place, which will limit at what times we can test. Also with 

the instantaneous and average temperature upper limits being identical (800F), this will effectively 

further reduce the average temperature upper limit of 800F, down to perhaps 780F or less. This 

73-78 deg F average temperature window is very narrow for high production around the clock 

testing. See TSD page 514.

9

For AC17, the Alliance recommending setting the soak fan speed at 4mph instead of 0mph. 

Although EPA agreed with this comment, and §86.167-17 (i)(5) does allow 4mph fan speed, this is 

only for “...maintenance of ambient requirements.” This provision should cite this as a means of 

reflecting real-world conditions.
10

For AC17, the Alliance recommended allowing the window opening for wires into the interior to 

be covered up. Although EPA agreed, no such allowance is shown in §86.167-17. Page 518 of the 

Technical Support Document states, “Also, if the windows on the vehicle need to be partially open 

to allow for instrumentation and writing to be passed through to the interior, a temporary seal 

(e.g. foam or tape) can be used to close the window gap.” Incorporating such an allowance in the 

regulatory language is preferred.

11

For AC17, the Alliance recommended adding “nominal” to the time on the test flow chart in 

§86.167-17(a). We are unable to verify whether this was done (no chart is shown in the final rule 

– see p. 1800 where we believe the figure was to be included).

12

For AC17, the Alliance recommended widening the average and instantaneous test humidity and 

temperature specs. EPA left the tolerances for temperature and humidity as proposed, but 

stipulated that these tolerances apply only during the emissions measurement portions of the 

test, and temperature and humidity deviations during the non-emissions measurement portions 

of the test (e.g. preconditioning and soak) may exceed these tolerances, as long at the duration of 

the deviation is no more than three minutes. In addition, EPA will allow manufacturers to use a 

30-second moving average on the temperature tolerance, instead of an instantaneous 

temperature value (see§86.167-17(i)(1)(i)). The Alliance asked for a wider tolerance on the 

average temperature from 77±20F to 77±30F. ±20F is a tight tolerance to maintain for all vehicle 

types and basically represents the accuracy tolerance of a single temperature probe, and leaves 

no allowance for variation between multiple temperature probes used in the test facility, the air 

handling and fan speed controls, and vehicle operating impacts to this temperature 

measurement). See TSD p. 519.

13

For AC17, the Alliance recommended “nominal” interior thermocouple location specifications. 

EPA agreed in the TSD page 530 for headrest locations (For headrest locations, the temperature 

measuring devices shall be nominally 30 millimeters behind the center of the headrest), but then 

did not implement this change in the regulations. §86.167-17(j)(1)(ii) states this temperature 

probe “...shall be 30mm behind each headrest”. This requires the temperature probe to be 

located to within 0.49mm of 30mm, which is neither executable nor practical. “...shall be 

30mm...” should be replaced with “...shall be nominally 30mm...” See p. 1803.

14

For AC17, the Alliance recommended that the requirement for “6 volts at the motor” is too 

unwieldy a specification to be reliably executed in high volume testing and may not even be 

achievable, given varying motor voltage configurations such as vehicles with systems other than 

12-volt. Instead the Alliance recommended for manual blower speed settings that it be reduced to 

the setting closest to “6 volts at the motor” or the blower switch position at 50% of maximum 

blower speed, or immediately below 50% if there are an odd number of positions. EPA disagreed. 

See p. 1804.

15

The Alliance continues to have a concern on how to verify this 6 volt requirement. What if fans 

operate at different voltages, either now or in the future? What if the manual switch positions 

don’t hit 6 volts? Using a nominal 50% of maximum fan speed is much more universal and 

prescriptive.

16

Also, the word “nominal” should be added to the requirement “...to provide 55 deg F...” since (1) 

this temperature may change with different segments of the test (idles, accelerations, cruses, 

decelerations) or (2) with some vehicles may not achievable or stable at this idle period, and (3) 

implies a tolerance of ±0.49 deg F which may be difficult to set in such a short period of time.

17

Finally, on vehicles that "default to recirculated air above 75 deg F," the OEM should have the 

option to let this feature function as intended and not be required to start in recirculated air and 

change to outside air at the first idle of the SC03. 
18

For AC 17, the Alliance recommended an expanded time tolerance for turn-on and warming up of 

solar lamps. EPA agreed that the 30 minute soak time is a nominal time requirement and not a 

precise interval, as the test involves coordination of the operator exiting and entering the vehicle 

at the beginning and end of the soak period as well as activation of the solar lamps (see TSD page 

419). However this preamble allowance did not become part of the regulation §86.167-17(l)(8) 

which states:

“Following the preconditioning cycle, the test vehicle and cooling fan(s) are turned off, all windows 

are rolled up, and the vehicle is allowed to soak in the ambient conditions of paragraph (i) of this 

section for 30 ±1 minutes. If emissions are being measured with the air conditioner operating, the 

solar heat system must be turned on and generating 850 W/m2 within 1 minute of turning the 

engine off. Otherwise the solar heat system shall be turned off.”

Comments: (1) The 30 minute soak time is not nominal, rather is precisely defined in the 

regulations. (2) The second sentence still gives very prescriptive requirements on how quickly 

that the solar lights need to be turned on (“...within 1 minute...”) and generating 850 W/m2 lights. 

Our facilities simply cannot meet this requirement and there is no technical need for such a fast 

turn on time of solar lights especially if the preamble intent was to make this timing nominal. The 

Alliance’s original recommendation was:

“The solar heat system must be turned on within one minute of turning the engine off. The 30 

minute soak starts immediately after the solar load has achieved 850 ± 45 W/m2. Facility 

calibration data on solar lamp warm-up can be used to establish the start of solar soak time. Total 

soak time would be time to turn on the lights (e.g., one minute) plus lamp warm-up time (from 

calibration data) plus 30 minute solar soak. For example if the facility calibration demonstrates the 

lamps reach 850 W/m 2 within two minutes, the soak time can be standardized at 33 minutes 

after engine off for that facility.”

19

For AC17, the Alliance recommended some form of driver comfort ventilation for the air 

conditioning off test modes, on SC03 and HFET drive cycles. However §86.167-17(l)(8) requires 

“...all windows are rolled up...”, and (9) requires “... the air conditioning system should be 

completely off.” This puts the driver in a sealed vehicle with no ventilation. Provisions need to be 

made to allow the driver to get sufficient cooling, such as allowing the windows to be partially or 

fully opened during the “air conditioning off” portion of the test.

20

For AC17 , §86.167-17(l) (12)&(13), the prescribed phase timing and emissions sampling between 

the SC03 and HFET cycles is problematic because it conflicts with current SC03 and HFET CFR 

requirements. We recommend the SC03 and HFET cycles be run back to back with no time delay 

during the transition. For §86.167-17(l)(12) we recommend the SC03 should end emissions 

sampling 6 seconds after the end of the last deceleration [similar to §86.160-00 (d)(10)&(11)], and 

for HFET - start emissions sampling 2 seconds before the first acceleration [600.111-08 

(b)(9)(viii)]. Doing this puts the sample switch point between the two cycles. We also recommend 

deleting §86.167-17(l)(13) – the idle of 14-16 seconds between the SC03 and HFET cycles. (This 

issue was not identified in the Alliance comments on the NPRM but has been raised in the 

discussion of changes to Part 1066.)

21

86.1868-12(f)(1) (on page 1864) and §86.1868-12(g)(1) (on page 1966) both reference §86.167-14, 

however that section does not exist. We believe the section that should be referenced is §86.167-

17.