40 C.F.R. § 600 app III to Part 600

Current through September 30, 2024
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 carlineEngine code Trans Inertia weightAxle ratio Harmonically averaged. city MPG Specific label MPG1 Vehicle config. sales
Ajax1M-435002.7316.10011615,000
Ajax2A-335002.5615.90201635,000
Boredom III4M-440003.0814.23431410,000
Ajax3M-440003.3615.00001515,000
Boredom III8A-340002.5613.81381425,000
Boredom III5A-345003.0813.22031320,000
Castor5A-350003.0810.60061140,000

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.

Step II. Group vehicle fuel economy and sales data according to base level combinations within this basic engine.

Base level Transmission class Inertia weightMiles per gallon Projected vehicle configuration sales
AManual-43,50016.100115,000
BAutomatic-33,50015.902035,000
CManual-44,00014.234310,000
CManual-44,00015.000015,000
DAutomatic-34,00013.813825,000
EAutomatic-34,50013.220320,000
FAutomatic-35,00010.600640,000

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 transmission16.1001 mpg.
3,500 lb/A3 transmission15.9020 mpg.
4,000 lb/A3 transmission13.8138 mpg.
4,500 lb/A3 transmission13.2203 mpg.
5,000 lb/A3 transmission10.6006 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.

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Base level: M4 transmission, 4000 pounds:

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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.

AjaxM40.4000 at 3,500 lb16.1001
0.6000 at 4,000 lb14.6840
A30.3000 at 3,500 lb15.9020
0.7000 at 4,000 lb13.8138
DodoM40.4000 at 3,500 lb16.1001
0.6000 at 4,000 lb14.6840
A30.3000 at 3,500 lb15.9020
0.7000 at 4,000 lb13.8138
Boredom IIIM41.0000 at 4,000 lb14.6840
A30.2500 at 4,000 lb13.8138
0.7500 at 4,500 lb13.2203
CastorA30.2000 at 4,500 lb13.2203
0.8000 at 5,000 lb10.6006

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:

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Similarly, Ajax and Dodo 3.0 liter, 6 cylinder, M4 model type MPG is calculated as follows:

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Dodo 3.0 liter, 6 cylinder, A3 model type MPG is calculated as follows:

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Boredom III 3.0 liter 6 cylinder M4 model type MPG = 14.6840 mpg, which rounds to 15 mi./gal

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:

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Castor 3.0 liter, 6 cylinder, A3 model type MPG is calculated as follows:

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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.

40 C.F.R. 600 app III to Part 600

71 FR 77958, Dec. 27, 2006