EPA Decision Document:

Off Cycle Credits for Hyundai Motor
Group - Doowon Air Conditioning
Compressor

&EPA

United States
Environmental PrulutUon
Agency


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EPA Decision Document:
Off Cycle Credits for Hyundai Motor
Group - Doowon Air Conditioning

Compressor

Compliance Division
Office of Transportation and Air Quality
U.S. Environmental Protection Agency

A rnA ^ni^ed StatgB. _ „	EPA-420-R-22-019

Environmwntal Prol«clion	„„„„

r#i Ag en cy	August 2022


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EPA Decision Document: Off-Cycle Credits for
Hyundai Motor Group - Doowon Air Conditioning
Compressor

I.	Introduction

EPA's light-duty vehicle greenhouse gas (GHG) rules include opportunities for manufacturers to generate
C02 credits for technologies that provide C02 reductions not captured by the 2-cycle emissions test.
There are three pathways by which manufacturers can generate off-cycle credits: (1) a pre-determined
"menu" of technologies and credits that is available for 2014 and later model years, (2) a testing-based
option, and (3) an alternative methodology that includes opportunity for public comment. These are
described in more detail in Section II.

Pursuant to those rules, Hyundai Motor Group (Hyundai) submitted an application requesting off-cycle
credits for the use of a Doowon air conditioning compressor with crankcase suction valve (CS valve)
technology in vehicles equipped with this technology starting in model year 2022 and later.

This technology and methodology for demonstrating the effectiveness of this technology have been
previously approved through the public process by the EPA on multiple occasions. Therefore, the EPA is
not publishing this request and allowing for public comments as no adverse comments to this type of
technology have been received to date. Furthermore, the EPA is hereby approving the technologies,
methodologies for determining credits, and credit levels as described in the application from Hyundai.

Section II of this document provides background on EPA's off-cycle credits program. Section III provides
EPA's decision. This decision document applies only to the application referenced herein.

II.	EPA's Off-cycle Credits Program

EPA's light-duty vehicle greenhouse gas (GHG) program provides three pathways by which a
manufacturer may accrue off-cycle carbon dioxide (C02) credits for those off-cycle technologies that
achieve C02 reductions in the real world but where those reductions are not adequately captured on the
test procedure used to determine compliance with the C02 standards. The first is a predetermined list of
credit values for specific off-cycle technologies that may be used beginning in model year 2014.1 This
pathway allows manufacturers to use conservative credit values established by EPA for a wide range of
technologies, with minimal data submittal or testing requirements. In cases where additional laboratory
testing can demonstrate emission benefits of an off-cycle technology, a second pathway allows

1 See 40 CFR 86.1869-12(b).

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manufacturers to use a broader array of emission tests (known as "5-cycle" testing because the
methodology uses five different testing procedures) to demonstrate and justify off-cycle C02 credits.2
The additional emission tests allow emission benefits to be demonstrated over some elements of real-
world driving not captured by the GHG compliance tests, including high speeds, hard accelerations, and
cold temperatures. Credits determined according to this methodology do not undergo additional public
review. The third and last pathway allows manufacturers to seek EPA approval to use an alternative
methodology for determining the off-cycle C02 credits.3 This option is only available if the benefit of the
off-cycle technology cannot be adequately demonstrated using the 5-cycle methodology. Manufacturers
may also use this option for model years prior to 2014 to demonstrate off-cycle C02 reductions for
technologies that are on the predetermined list, or to demonstrate reductions that exceed those
available via use of the predetermined list.

Under the regulations, a manufacturer seeking to demonstrate off-cycle credits with an alternative
methodology (i.e., under the third pathway described above) must describe a methodology that meets
the following criteria:

•	Use modeling, on-road testing, on-road data collection, or other approved analytical or
engineering methods;

•	Be robust, verifiable, and capable of demonstrating the real-world emissions benefit with strong
statistical significance;

•	Result in a demonstration of baseline and controlled emissions over a wide range of driving
conditions and number of vehicles such that issues of data uncertainty are minimized;

•	Result in data on a model type basis unless the manufacturer demonstrates that another basis is
appropriate and adequate.

Further, the regulations specify the following requirements regarding an application for off-cycle C02
credits:

•	A manufacturer requesting off-cycle credits must develop a methodology for demonstrating and
determining the benefit of the off-cycle technology and carry out any necessary testing and
analysis required to support that methodology.

•	A manufacturer requesting off-cycle credits must conduct testing and/or prepare engineering
analyses that demonstrate the in-use durability of the technology for the full useful life of the
vehicle.

•	The application must contain a detailed description of the off-cycle technology and how it
functions to reduce C02 emissions under conditions not represented on the compliance tests.

•	The application must contain a list of the vehicle model(s) which will be equipped with the
technology.

2	See 40 CFR 86.1869-12(c).

3	See 40 CFR 86.1869-12(d).

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•	The application must contain a detailed description of the test vehicles selected and an
engineering analysis that supports the selection of those vehicles for testing.

•	The application must contain all testing and/or simulation data required under the regulations,
plus any other data the manufacturer has considered in the analysis.

Finally, the alternative methodology must be approved by EPA prior to the manufacturer using it to
generate credits. As part of the review process defined by regulation, the alternative methodology
submitted to EPA for consideration must be made available for public comment.4 EPA will consider
public comments as part of its final decision to approve or deny the request for off-cycle credits.

Although these credits are requested under regulatory provisions that don't explicitly require
limitations, or caps, on credit values, EPA is stipulating here that credits for technologies for which there
is a regulatory cap must be held to the applicable regulatory cap, if such credits are approved by EPA.
For example, for reasons described in the implementing rulemaking documents and analyses, EPA
established caps on thermal technology credits of 3.0 grams/mile for cars and 4.3 grams/mile for trucks.
The rationale for these caps is applicable regardless of the off-cycle pathway being used to achieve such
credits. EPA also established caps on technologies that improve the efficiency of air conditioning
systems (5 grams/mile for cars and 7.2 grams per mile for trucks). Thus, credits approved in this Decision
Document are being approved only to the extent that the regulatory caps on credits for certain
technologies or categories of technologies are not exceeded.

III. EPA Decisions on Off-cycle Credit Applications

A. Doowon Air Conditioning Compressor with CS Valve Technology

Hyundai applied for off-cycle credits for an air conditioning compressor manufactured by Doowon that
has been shown to result in efficiency improvements warranting air conditioning efficiency credits
beyond those provided in the regulations. This compressor, called the Doowon compressor with
crankcase suction valve (CS valve) technology, improves the internal valve system within the variable-
displacement compressor to reduce the internal refrigerant flow necessary throughout the range of
displacements that the compressor may use during its operating cycle. The addition of a variable
crankcase suction valve allows a larger mass flow under maximum capacity and compressor start-up
conditions (when high flow is ideal), and then it can reduce to smaller openings with reduced mass flow
in mid-or low-capacity conditions. The refrigerant exiting the crankcase is thus optimized across the
range of operating conditions, reducing the overall energy consumption of the air conditioning system.
EPA previously approved credits for the use of similar technology, manufactured by Hannon for this
manufacturer, and other compressors manufactured by Denso, for other vehicle manufacturers.

The manufacturer has calculated credit values for this compressor model to be 1.3 g/mi. The
manufacturer cited bench testing and Life Cycle Climate Performance (LCCP) modeling and analysis to

4 See 40 CFR 86.1869-12(d)(2).

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back up this value. These values are similar to values already approved for similar technology in other
supplier's air conditioning compressors.5 6 The application with test data for Hyundai can be found here.

EPA has evaluated the application and finds that the methodologies described therein are sound and
appropriate. Therefore, EPA is approving the credits requested by Hyundai for the 2022 model year and
later for all vehicles using this technology as described in Hyundai's application. Caps or limits on credits
that are specified in the regulations also apply to the credits being approved in this document. All
information necessary to determine the total Megagrams of credits must be included in the reporting to
EPA, and the total Megagrams for each fleet and model year should be included in a summary of credit
averaging, banking, and trading.

5	"EPA Decision Document: Off-Cycle Credits for General Motors and Toyota Motor Corporation," EPA-
420-R-18-014, June 2018

6	"EPA Decision Document: Off-cycle Credits for Fiat Chrysler Automobiles, Ford Motor Company, and
General Motors Corporation." Compliance Division, Office of Transportation and Air Quality, U.S. Environmental
Protection Agency. EPA-420-R-15-014, September 2015.

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