40 CFR Part 600, Appendix III to Part 600 - Sample Fuel Economy Label Calculation

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View PDF at GPO Pt. 600, App. III
Appendix III to Part 600—Sample Fuel Economy Label Calculation
Suppose that a manufacturer called Mizer Motors has a product line composed of eight car lines. Of these eight, four are available with the 3.0 liter, 6 cylinder, sequential multi-point fuel injection, 4-valve per cylinder, and 3-way catalyst engine. These four car lines are:
Ajax
Boredom III
Dodo
Castor (Station Wagon)
A. A car line is defined in subpart A (with additional guidance provided in EPA Advisory Circular 89) as a group of vehicles within a make or division which has a degree of commonality in construction. Car line does not consider any level of decor or opulence and is not generally distinguished by such characteristics as roofline, number of doors, seats, or windows. Station wagons and light duty trucks are, however, identified separately from the remainder of each car line. In other words, a Castor station wagon would be considered a different car line than the normal Castor car line made up of sedans, coupes, etc.
B. The engine considered here is defined as a basic engine in subpart A of this part (with additional guidance provided in EPA Advisory Circular 83A). A basic engine is a unique combination of manufacturer, engine displacement, number of cylinders, fuel system, catalyst usage and other engine and emission control system characteristics specified by the Administrator. A model type is a unique combination of car line, basic engine, and transmission class. Thus Ajax is a car line but Ajax 3.0 liter, 6 cylinder manual four-speed transmission is a model type whereas Ajax 3.0 liter, 6 cylinder automatic three-speed transmission is a different model type.
C. The following calculations provide an example of the procedures described in subpart C of this part for the calculation of vehicle configuration and model type fuel economy values. In order to simplify the presentation, only city fuel economy values are included (as determined by either the derived 5-cycle method or vehicle-specific 5-cycle based method). The procedure is identical for highway and combined fuel economy values.
Step I. Input data as supplied by the manufacturer or as determined from testing conducted by the Administrator.
Manufacturer—Mizer Motors
Basic Engine: (3.0 liter, 6 cylinder, sequential multi-point fuel injection, 4-valve per cylinder, 3-way catalyst).
Test vehicle carline Engine code Trans Inertia weight Axle ratio Harmonically averaged. city MPG Specific label MPG 1 Vehicle config. sales
1 The vehicle configuration fuel economy values, rounded to the nearest mile per gallon, are the fuel economy values that would be used on specific labels for that vehicle configuration.
Ajax 1 M-4 3500 2.73 16.1001 16 15,000
Ajax 2 A-3 3500 2.56 15.9020 16 35,000
Boredom III 4 M-4 4000 3.08 14.2343 14 10,000
Ajax 3 M-4 4000 3.36 15.0000 15 15,000
Boredom III 8 A-3 4000 2.56 13.8138 14 25,000
Boredom III 5 A-3 4500 3.08 13.2203 13 20,000
Castor 5 A-3 5000 3.08 10.6006 11 40,000
Step II. Group vehicle fuel economy and sales data according to base level combinations within this basic engine.
Base level Transmission class Inertia weight Miles per gallon Projected vehicle configuration sales
A Manual-4 3,500 16.1001 15,000
B Automatic-3 3,500 15.9020 35,000
C Manual-4 4,000 14.2343 10,000
C Manual-4 4,000 15.0000 15,000
D Automatic-3 4,000 13.8138 25,000
E Automatic-3 4,500 13.2203 20,000
F Automatic-3 5,000 10.6006 40,000
Step III. Determine base level fuel economy values.
A. For all the base levels except the base level which includes 4,000 pound, manual four-speed transmission data, the base level fuel economy is as noted in Step II since only one vehicle configuration was tested within each of these base levels.
3,500 lb/M4 transmission 16.1001 mpg.
3,500 lb/A3 transmission 15.9020 mpg.
4,000 lb/A3 transmission 13.8138 mpg.
4,500 lb/A3 transmission 13.2203 mpg.
5,000 lb/A3 transmission 10.6006 mpg.
B. Since data from more than one vehicle configuration are included in the 4,000-pound, manual four-speed transmission base level, this fuel economy is harmonically averaged in proportion to the percentage of total sales of all vehicle configurations tested within that base level represented by each vehicle configuration tested within that base level.
Base level: M4 transmission, 4000 pounds:
Therefore, the 4000 pound, M4 transmission fuel economy is 14.6840 miles per gallon.
Note that the car line of the test vehicle using a given engine makes no difference—only the weight and transmission do.
Step IV. For each model type offered by the manufacturer with that basic engine, determine the sales fraction represented by each inertia weight/transmission class combination and the corresponding fuel economy.
Ajax M4 0.4000 at 3,500 lb 16.1001
0.6000 at 4,000 lb 14.6840
A3 0.3000 at 3,500 lb 15.9020
0.7000 at 4,000 lb 13.8138
Dodo M4 0.4000 at 3,500 lb 16.1001
0.6000 at 4,000 lb 14.6840
A3 0.3000 at 3,500 lb 15.9020
0.7000 at 4,000 lb 13.8138
Boredom III M4 1.0000 at 4,000 lb 14.6840
A3 0.2500 at 4,000 lb 13.8138
0.7500 at 4,500 lb 13.2203
Castor A3 0.2000 at 4,500 lb 13.2203
0.8000 at 5,000 lb 10.6006
Step V. Determine fuel economy for each model type (that is, car line/basic engine/transmission class combination).
Ajax, 3.0 liter, 6 cylinder, A3 transmission, model type MPG is calculated as follows:
Similarly, Ajax and Dodo 3.0 liter, 6 cylinder, M4 model type MPG is calculated as follows:
Dodo 3.0 liter, 6 cylinder, A3 model type MPG is calculated as follows:
Boredom III 3.0 liter 6 cylinder M4 model type MPG = 14.6840 mpg, which rounds to 15 mi./gal1

Footnote(s):
1 The model type fuel economy values rounded to the nearest mile per gallon, are the fuel economy values listed in the EPA Fuel Economy Guide and used on the general labels (window stickers) for production vehicles for that model year.

Boredom III 3.0 liter, 6 cylinder, A3 model type MPG is calculated as follows:
Castor 3.0 liter, 6 cylinder, A3 model type MPG is calculated as follows:
Note that even though no Dodo was actually tested, this approach permits its fuel economy figure to be estimated, based on the inertia weight distribution of projected Dodo sales within a specific engine and transmission grouping.
[71 FR 77958, Dec. 27, 2006]

Title 40 published on 2013-07-01

The following are only the Rules published in the Federal Register after the published date of Title 40.

For a complete list of all Rules, Proposed Rules, and Notices view the Rulemaking tab.

  • 2014-04-28; vol. 79 # 81 - Monday, April 28, 2014
    1. 79 FR 23414 - Control of Air Pollution From Motor Vehicles: Tier 3 Motor Vehicle Emission and Fuel Standards
      GPO FDSys XML | Text
      ENVIRONMENTAL PROTECTION AGENCY
      Final rule.
      This final rule is effective on June 27, 2014. The incorporation by reference of certain publications listed in this regulation is approved by the Director of the Federal Register as of June 27, 2014.
      40 CFR Parts 79, 80, 85, 86, 600, 1036, 1037, 1039, 1042, 1048, 1054, 1065, and 1066

Title 40 published on 2013-07-01

The following are ALL rules, proposed rules, and notices (chronologically) published in the Federal Register relating to 40 CFR 600 after this date.

  • 2014-04-28; vol. 79 # 81 - Monday, April 28, 2014
    1. 79 FR 23414 - Control of Air Pollution From Motor Vehicles: Tier 3 Motor Vehicle Emission and Fuel Standards
      GPO FDSys XML | Text
      ENVIRONMENTAL PROTECTION AGENCY
      Final rule.
      This final rule is effective on June 27, 2014. The incorporation by reference of certain publications listed in this regulation is approved by the Director of the Federal Register as of June 27, 2014.
      40 CFR Parts 79, 80, 85, 86, 600, 1036, 1037, 1039, 1042, 1048, 1054, 1065, and 1066