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Alternative Methods for Calculating Off-Cycle Credits Under the Light-Duty Vehicle Greenhouse Gas Emissions Program: Applications From Toyota Motor North America

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Environmental Protection Agency (EPA).




The Environmental Protection Agency (EPA) is requesting comment on applications from Toyota Motor North America (“Toyota”) for off-cycle carbon dioxide (CO2) credits under EPA's light-duty vehicle greenhouse gas emissions standards. “Off-cycle” emission reductions can be achieved by employing technologies that result in real-world benefits, but where that benefit is not adequately captured on the test procedures used by manufacturers to demonstrate compliance with emission standards. EPA's light-duty vehicle greenhouse gas program acknowledges these benefits by giving automobile manufacturers several options for generating “off-cycle” CO2 credits. Under the regulations, a manufacturer may apply for CO2 credits for off-cycle technologies that result in off-cycle benefits. In these cases, a manufacturer must provide EPA with a proposed methodology for determining the real-world off-cycle benefit. Toyota has submitted applications that describe methodologies for determining off-cycle credits from technologies described in their applications. Pursuant to applicable regulations, EPA is making these off-cycle credit calculation methodologies available for public comment.


Comments must be received on or before May 1, 2020.


Submit your comments, identified by Docket ID No. EPA-HQ- OAR-2019-0333, to the Federal eRulemaking Portal: Follow the online instructions for submitting comments. Once submitted, comments cannot be edited or withdrawn. The EPA may publish any comment received to its public docket. Do not submit electronically any information you consider to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Multimedia submissions (audio, video, etc.) must be accompanied by a written comment. The written comment is considered the official comment and should include discussion of all points you wish to make. The EPA will generally not consider comments or comment contents located outside of the primary submission (i.e. on the web, cloud, or other file sharing system). For additional submission methods, the full EPA public comment policy, information about CBI or multimedia submissions, and general guidance on making effective comments, please visit​dockets/​commenting-epa-dockets.

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Linc Wehrly, Director, Light Duty Vehicle Center, Compliance Division, Office of Transportation and Air Quality, U.S. Environmental Protection Agency, 2000 Traverwood Drive, Ann Arbor, MI 48105. Telephone: (734) 214-4286. Fax: (734) 214-4053. Email address:

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I. Background

EPA's light-duty vehicle greenhouse gas (GHG) program provides three pathways by which a manufacturer may accrue off-cycle carbon dioxide (CO2) credits for those technologies that achieve CO2 reductions in the real world but where those reductions are not adequately captured on the test used to determine compliance with the CO2 standards, and which are not otherwise reflected in the standards' stringency. The first pathway 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, if the technologies meet EPA regulatory definitions. In cases where the off-cycle technology is not on the menu but additional laboratory testing can demonstrate emission benefits, a second pathway allows 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 CO2 credits.[2] The additional emission tests allow emission benefits to be demonstrated over some elements of real-world driving not adequately captured by the GHG compliance tests, including high speeds, hard accelerations, and cold temperatures. These first two methodologies were completely defined through notice and comment rulemaking and therefore no additional process is necessary for manufacturers to use these methods. The third and last pathway allows manufacturers to seek EPA approval to use an alternative methodology for determining the off-cycle CO2 credits.[3] This option is only available if the benefit of the technology cannot be adequately demonstrated using the 5-cycle methodology. Manufacturers may also use this option 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 CO2 credits:

  • A manufacturer requesting off-cycle credits must develop a methodology for demonstrating and determining the benefit of the off-cycle technology and Start Printed Page 18228carry 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 CO2 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.
  • 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.

II. Off-Cycle Credit Applications

A. Denso Electric Scroll Air Conditioning Compressor

Toyota is applying for off-cycle GHG credits for the use of the Denso Electric Scroll Air Conditioning Compressor Variation B (ESB) with pressure adjusting valve technology. This technology improves the efficiency of the electric scroll compressor using a pressure adjusting valve to optimize back pressure on the fixed scroll and reduce mechanical losses. This is similar to the off cycle alternative method technology for the belt driven Denso SES/SAS compressor, for which credits were granted to Toyota in June 2018.[5] The requested credit amount was confirmed by Toyota through bench testing, following the method in the Society of Automotive Engineers (SAE) procedure J2765, to confirm air conditioning system power reduction of the technology resulting from the reduced mechanical losses in the compressor. The SAE J2766 standard (using the GREEN MAC Life Cycle Climate Performance Model) was used to calculate the normalized grams CO2 per mile improvement of the technology for the U.S. market. The CO2 grams per mile improvement was derived from the bench test results.

Toyota is applying for a credit of 1.9 grams/mile for 2016 and later model years for vehicles sold in the U.S. and equipped with the Denso ESB air conditioning compressor. EPA considers this compressor technology to be a technology that, if approved, will be subject to the maximum limits for an A/C system of 5.0 g/mi for passenger automobiles and 7.2 g/mi for light trucks specified in the regulations.[6] Details of the testing and analysis can be found in the manufacturer's applications.

B. Dual Layer HVAC Technology

Toyota is applying for off-cycle GHG credits for the use of a dual layer (or 2-layer) HVAC technology. Ventilation and heat transfer losses between the cabin and outside ambient are the key HVAC thermal losses during warmup. Ventilation losses can be reduced by recirculating the cabin air, but this has the adverse effect of building up cabin humidity, which can then become a safety hazard due to increased windshield fogging. Dual layer HVAC uses two separate “layers” of airflow within the vehicle and a two‐stage fan that can recirculate air through the lower outlets while flowing fresh, low humidity air through the upper ducts (includes the windshield defroster). The module has a door that selects full fresh, full recirculate, or dual layer mode based on logic parameters. Low humidity air is needed to better defog the windshield and recirculated air improves warm up performance. With the use of recirculated air less engine heat is needed to warm the cabin, and both the cabin and the engine warm up faster. Faster engine warmup improves vehicle efficiency.

Toyota is applying for a credit of 0.6 grams/mile for 2016 and later model years for vehicles sold in the U.S. and equipped with the dual layer HVAC technology. Details of the testing and analysis can be found in the manufacturer's applications.

III. EPA Decision Process

EPA has reviewed the applications for completeness and is now making the applications available for public review and comment as required by the regulations. The off-cycle credit applications submitted by the manufacturers (with confidential business information redacted) have been placed in the public docket (see ADDRESSES section above) and on EPA's website at​vehicle-and-engine-certification/​compliance-information-light-duty-greenhouse-gas-ghg-standards.

EPA is providing a 30-day comment period on the applications for off-cycle credits described in this document, as specified by the regulations. The manufacturers may submit a written rebuttal of comments for EPA's consideration, or may revise an application in response to comments. After reviewing any public comments and any rebuttal of comments submitted by manufacturers, EPA will make a final decision regarding the credit requests. EPA will make its decision available to the public by placing a decision document (or multiple decision documents) in the docket and on EPA's website at the same manufacturer-specific pages shown above. While the broad methodologies used by these manufacturers could potentially be used for other vehicles and by other manufacturers, the vehicle specific data needed to demonstrate the off-cycle emissions reductions would likely be different. In such cases, a new application would be required, including an opportunity for public comment.

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Dated: March 25, 2020.

Byron J. Bunker,

Director, Compliance Division, Office of Transportation and Air Quality, Office of Air and Radiation.

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5.  “EPA Decision Document: Off-cycle Credits for General Motors and Toyota Motor Corporation.” Compliance Division, Office of Transportation and Air Quality, U.S. Environmental Protection Agency. EPA-420-R-18-014, June 2018.

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[FR Doc. 2020-06709 Filed 3-31-20; 8:45 am]