UNITED STATES ENVIRONMENTAL PROTECTION AGENCY NATIONAL VEHICLE AND FUEL EMISSIONS LABORATORY

2565 PLYMOUTH ROAD ANN ARBOR, MI 48105

- 2498

OFFICE OF AIR AND R ADIATION

July 1 6 , 2015

MEMORANDUM

SUBJECT: Example CO 2 Emissions Calculations for Box Trailers

FROM: Jessica Brakora, Engineer, Assessment and Standards Division

TO: Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium

- and

Heavy

- Duty Engines and Vehicles

- Phase 2

- Docket EPA

- HQ

- OAR

- 201 4

- 0827

Introduction Attached is a Microsoft Excel spreadsheet that can be used to estimate the CO 2 emissions from box trailers, while considering production volumes and potential averaging. The calculations in this spreadsheet use the GEM

- based equation constants derived from the proposed GEM Executable. It is likely there will be updates to the GEM Executable for the F inal Rule. T he constants for the proposed GEM

- based equation and the standards generated from the equation are subject to change as a result of those updates. Note that the equation constants, and the resulting standards, in the attached spreadsheet
vary slightly from those in the preamble and regulations of the NPRM. See our memo to the docket titled:

“ Numerical Standards for Tractors, Trailers, and Vocational Vehicles Based on the GEM Executable Code; and Derivation of the Numerical Engine Standards ” July 2015

The spread sheet is for illustrative purposes only. It will provide an estimate of the CO 2 emissions, but these values cannot be used for compliance. EPA and NHTSA will make a formal compliance template after we issue the Final Rule. The calc ulations do not use the same method for rounding results as used in compliance. Also, these calculations do not consider deficits that we are currently proposing to allow manufacturers to generate and carry

- over for up to three years. All regulation refe rences in this memo are with respect to the proposed provisions in Title 40 of the Code of Federal Regulations.

Using the Spreadsheet In the attached spreadsheet, users can update the white

- colored cells with their trailer information. The green cells w ill automatically update according to those inputs. The second tab (“ForReference”) includes tables from the proposed regulations. None of the information in the ForReference tab is used for calculations. These tables may help users identify appropriate values for the inputs.2

Users can change the model year ( white box above the Calculation Table ) to the year of interest. The standards will update automatically. Note that we are not proposing standards before MY 2018 and no standards will be shown if a year earlier than 2018 is used.

In the Calculation Table

, Column A is for the trailer Configuration name . This can be any user

specified name to identify a given set of trailers ; it does not factor into the calculations. A single “configuration” would include a unique set of work performing devices (Columns D and E ), and performance characteristics (Columns F

- I). Column B identifies the trailer sub category based on length and whether it is a dry or refrigerated van. Column C is the Averaging Se t /Family . By default, there are four averaging sets that align with the subcategories (i.e., LDV, LRV, SDV, and SRV), but manufacturers can include trailers with less

- stringent standards in a more

- stringent averaging set to reduce the number of tests and reporting required. See 1037.230(d) and 1037.740(a). For instance, a long refrigerated van (LRV) configuration could be included in the long dry van (LDV) family, because LDVs have more

- stringent standards.

If a trailer configuration has one or more of t he “work performing devices” in Columns D and E , users would enter a “Y” in the field. Otherwise they would enter an “N”. These columns are used to determine any r educed a ero o ptions (i.e., partial

- or non

- aero) that are available for the given configura tion. Column K will automatically display the aero options. Any configuration that has a “Y” in both Columns D and E would be a “Non

- Aero” trailer. There are no numerical standards for non

- aero trailers and no CO 2 value is calculated . Configurations th at have a “Y” in one of the work

- performing device columns are eligible for the “Partial

- Aero” option in MY 2027 and later. For years earlier than 2027, Column K will show that these configurations are “Full

- Aero”, since the proposed standards are the sam e for full

- and p artial

- a ero trailers during those model years

. If users do not want to consider partial

- aero trailers (i.e., believe they can meet the full

- aero standard in 2027), they would change any “Y” entries in under the Work

- Performing Devices columns (Columns D and E) to “N” and those trailers would be facto red into the full

- aero calculations.

Columns F through I are the performance parameters used as inputs to the proposed GEM

- based compliance equation. If the trailer configuration has an automatic tire inflation system (ATIS) installed, users enter a valu e of 0.985 in Column F. Otherwise, users enter a value of 1.0. Tire rolling resistance level (TRRL) values in Column G are the coefficient of rolling resistance (CRR) values

, likely obtained from testing performed by the tire manufacturers. TRRL values can range from 3.0 to 7.0 kg/ton. Delta C D A value s in Column G would come from aerodynamic tests performed by the trailer manufacturer, a contractor, or an aero device manufacturer that had its results pre

- approved. The aero test results would determine w hich of the trailer aerodynamic bins in Table 2 of 1037.515 applies, and the user would enter the associated delta C D A from the table into Column H for the given configuration

. Weight reduction values are obtained from the list of qualifying component sub stitutions in Table 3 of 1037.515 (trailer

- specific components) and Table 7 of 1037.520 (wheel

- related weight reductions). Users would sum the weight of all qualifying components installed on the given configuration, and enter that value in Column I. The TRRL and Delta C D A values should be rounded to the nearest tenth (0.1). The Weight Reduction values should be rounded to the nearest whole number (1.0). The aerodynamic bin table and the two weight reduction tables from the proposed regulations are repr oduced in the “ForReference” tab of the spreadsheet.3

This spreadsheet will not provide a warning if performance parameters are out of range. Table 1 below summarizes the limits for each parameter. Note that CO 2 will only be calculated if all four perfor mance parameter columns contain values.

Table 1: Limits for Performance Parameters in Proposed GEM

- Based Trailer Compliance Equation

User

- Defined Performance Parameter Units Minimum Value Maximum

Value Aerodynamic Drag Area (CdA) m^2 0.0 2.0 Tire Rolling Resistance Level (TRRL) kg/t 3.0 7.0 Weight Reduction lbs 0 .0 10,000 Automatic Tire Inflation System none 0.985 (yes) 1.0 (no)

The final user input is the production volume in Column J. Users would enter the number of trailers sold for that given configuration. This value is used to calculate the average for each full

- a ero averaging set/family.

Columns K throug h O of the Calculation Table display the results for each configuration. Non

- Aero trailers do not have numerical standards and have an “N/A” in the columns that refer to standards. Pa rtial

- a ero trailers have numerical standards, but are not eligible for averaging in this proposal. As a result, each partial

- aero trailer config uration must meet the standard to comply. In the spreadsheet, rows that contain p artial

- aero configurations that are above the standard are highlight ed pink so users can easily identify those trailers. Full

- aero trailers are not highlighted if they are a bove the standard, because those trailers could be accounted for with averaging.

The results are summarized in the two tables at the top of the worksheet. Summary Table 1 summarizes the results for the full

- a ero box trailer families that are eligible f or averaging in the proposed rule. Summary Table 2 summarizes the results for the p artial

- and n on

- a ero box trailer families that are not eligible for averaging in the proposal.

In Summary Table 1 calculations that do not apply (i.e., a trailer type is not included in the Calculation Table) are shown as “N/A”. The first row of Summary Table 1 displays the production

- weighted average for each family, considering the production volume of individual configuration s in the family

. T he second row shows the proposed standard for the given family in that model year for comparison

, and the third row indicates if the average value meets the standard (“NO” if above and “yes” if at or below the standard) . The last three row s are for refere nce only. They are not used in the calculation. They indicate the number of configurations that are above the standard, the total number of configurations in that family, and the total production volume of that family. If the “Total Configurations Above Standard” row is zero for any family, averaging is not required, since all trailers within that family are compliant.

Summary Table 2 does not contain an average CO 2 value , because all configurations that are assigned a partial

- or non

- aero status must meet their reduced

- aero standards

. For reference, the table shows the standard for the family, followed by the number of configurations that are above the standard, the total configurations in the family, and the total production volu me for the family. A s mentioned previously,4

all partial

- aero configurations that are above the standard are highlighted in pink in the Calculation Table to quickly identify them

.

Conclusion This spreadsheet is intended to provide an estimate of CO 2 emissions. This spreadsheet cannot be used for compliance and users should not expect that the results from these calculations will match those from official compliance calculations.

Attached: Example Trailer Emissions Calculations Spreadsheet

– [ fi lename ]