[Code of Federal Regulations]
[Title 40, Volume 27]
[Revised as ofJuly 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR600.510-93]

[Page 910-913]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 600--FUEL ECONOMY OF MOTOR VEHICLES--Table of Contents
 
   Subpart F--Fuel Economy Regulations for Model Year 1978 Passenger
 
Sec. 600.510-93  Calculation of average fuel economy.

    (a) Average fuel economy will be calculated to the nearest 0.1 mpg 
for the classes of automobiles identified in this section, and the 
results of such calculations will be reported to the Secretary of 
Transportation for use in determining compliance with the applicable 
fuel economy standards.
    (1) An average fuel economy calculation will be made for the 
category of passenger automobiles that is domestically manufactured as 
defined in Sec. 600.511(d)(1).
    (2) An average fuel economy calculation will be made for the 
category of passenger automobiles that is not domestically manufactured 
as defined in Sec. 600.511(d)(2).
    (3) An average fuel economy calculation will be made for the 
category of light trucks that is domestically manufactured as defined in 
Sec. 600.511(e)(1).
    (4) An average fuel economy calculation will be made for the 
category of light trucks that is not domestically manufactured as 
defined in Sec. 600.511(e)(2).
    (b) For the purpose of calculating average fuel economy under 
paragraph (c), of this section:
    (1) All fuel economy data submitted in accordance with 
Sec. 600.006(e) or Sec. 600.502(c) shall be used.
    (2) The combined city/highway fuel economy will be calculated for 
each model type in accordance with Sec. 600.207 of this section except 
that:
    (i) Separate fuel economy values will be calculated for model types 
and base levels associated with car lines that are:
    (A) Domestically produced; and
    (B) Nondomestically produced and imported;
    (ii) Total model year production data, as required by this subpart, 
will be used instead of sales projections;
    (iii) The fuel economy value of diesel-powered model types will be 
multiplied by the factor 1.0 to correct gallons of diesel fuel to 
equivalent gallons of gasoline;
    (iv) The fuel economy value will be rounded to the nearest 0.1 mpg; 
and
    (v) At the manufacturer's option, those vehicle configurations that 
are selfcompensating to altitude changes may be separated by sales into 
high-altitude sales categories and low-altitude sales categories. These 
separate sales categories may then be treated (only for the purpose of 
this section) as separate configurations in accordance with the 
procedure of paragraph Sec. 600.207(a)(4)(ii).
    (3) The fuel economy value for each vehicle configuration is the 
combined

[[Page 911]]

fuel economy calculated according to Sec. 600.206 except that:
    (i) Separate fuel economy values will be calculated for vehicle 
configurations associated with car lines that are:
    (A) Domestically produced; and
    (B) Nondomestically produced and imported;
    (ii) Total model year production data, as required by this subpart 
will be used instead of sales projections; and
    (iii) The fuel economy value of diesel-powered model types will be 
multiplied by the factor 1.0 to convert gallons of diesel fuel to 
equivalent gallons of gasoline.
    (c) Except as permitted in paragraph (d) of this section, the 
average fuel economy will be calculated individually for each category 
identified in paragraph (a) of this section as follows:
    (1) Divide the total production volume of that category of 
automobiles; by
    (2) A sum of terms, each of which corresponds to a model type within 
that category of automobiles and is a fraction determined by dividing:
    (i) The number of automobiles of that model type produced by the 
manufacturer in the model year; by
    (ii) For gasoline-fueled and diesel-fueled model types, the fuel 
economy calculated for that model type in accordance with paragraph 
(b)(2) of this section; or
    (iii) For alcohol-fueled model types, the fuel economy value 
calculated for that model type in accordance with (b)(2) of this section 
divided by 0.15 and rounded to the nearest 0.1 mpg; or
    (iv) For natural gas-fueled model types, the fuel economy value 
calculated for that model type in accordance with (b)(2) of this section 
divided by 0.15 and rounded to the nearest 0.1 mpg; or
    (v) For alcohol dual fuel model types, for model years 1993 through 
2004, the harmonic average of the following two terms; the result 
rounded to the nearest 0.1 mpg:
    (A) The combined model type fuel economy value for operation on 
gasoline or diesel fuel as determined in Sec. 600.207(b)(5)(i); and
    (B) The combined model type fuel economy value for operation on 
alcohol fuel as determined in Sec. 600.207(b)(5)(ii) divided by 0.15 
provided the requirements of Sec. 600.510 (g) are met; or
    (vi) For natural gas dual fuel model types, for model years 1993 
through 2004, the harmonic average of the following two terms; the 
result rounded to the nearest 0.1 mpg:
    (A) The combined model type fuel economy value for operation on 
gasoline or diesel as determined in Sec. 600.207(b)(5)(i); and
    (B) The combined model type fuel economy value for operation on 
natural gas as determined in Sec. 600.207(b)(5)(ii) divided by 0.15 
provided the requirements of paragraph (g) of this section are met.
    (d) The Administrator may approve alternative calculation methods if 
they are part of an approved credit plan under the provisions of 15 
U.S.C. 2003.
    (e) For passenger categories identified in paragraphs (a) (1) and 
(2) of this section, the average fuel economy calculated in accordance 
with paragraph (c) of this section shall be adjusted using the following 
equation:

AFEadj = AFE[((0.55xaxc) + (0.45xc) + (0.5556xa) + 0.4487) / 
    ((0.55xa) + 0.45)] + IW

Where:

AFEadj = Adjusted average combined fuel economy, rounded to 
the nearest 0.1 mpg.
AFE = Average combined fuel economy as calculated in paragraph (c) of 
this section, rounded to the nearest 0.0001 mpg.
a = Sales-weight average (rounded to the nearest 0.0001 mpg) of all 
model type highway fuel economy values (rounded to the nearest 0.1 mpg) 
divided by the sales-weighted average (rounded to the nearest 0.0001 
mpg) of all model type city fuel economy values (rounded to the nearest 
0.1 mpg). The quotient shall be rounded to 4 decimal places. These 
average fuel economies shall be determined using the methodology of 
paragraph (c) of this section.
c = 0.0022 for the 1986 model year.
c = A constant value, fixed by model year. For 1987, the Administrator 
will specify the c value after the necessary laboratory humidity and 
test fuel data become available. For 1988 and later model years, the 
Administrator will specify the c value after the necessary laboratory 
humidity and test fuel data become available.
IW = (9.2917 x 10-3 x SF3 IWC x 
FE3 IWC) - (3.5123 x 10-3 x SF4 ETW x 
FE4 IWC)
    Note: Any calculated value of IW less than zero shall be set equal 
to zero.

[[Page 912]]

SF3 IWC = The 3000 lb. inertia weight class sales divided by 
total sales. The quotient shall be rounded to 4 decimal places.
SF4 ETW = The 4000 lb. equivalent test weight category sales 
divided by total sales. The quotient shall be rounded to 4 decimal 
places.
FE4 IWC = The sales-weighted average combined fuel economy of 
all 3000 lb. inertia weight class base levels in the compliance 
category. Round the result to the nearest 0.0001 mpg.
FE4 IWC = The sales-weighted average combined fuel economy of 
all 4000 lb. inertia weight class base levels in the compliance 
category. Round the result to the nearest 0.0001 mpg.

    (f) The Administrator shall calculate and apply additional average 
fuel economy adjustments if, after notice and opportunity for comment, 
the Administrator determines that, as a result of test procedure changes 
not previously considered, such correction is necessary to yield fuel 
economy test results that are comparable to those obtained under the 
1975 test procedures. In making such determinations, the Administrator 
must find that:
    (1) A directional change in measured fuel economy of an average 
vehicle can be predicted from a revision to the test procedures;
    (2) The magnitude of the change in measured fuel economy for any 
vehicle or fleet of vehicles caused by a revision to the test procedures 
is quantifiable from theoretical calculations or best available test 
data;
    (3) The impact of a change on average fuel economy is not due to 
eliminating the ability of manufacturers to take advantage of 
flexibility within the existing test procedures to gain measured 
improvements in fuel economy which are not the result of actual 
improvements in the fuel economy of production vehicles;
    (4) The impact of a change on average fuel economy is not solely due 
to a greater ability of manufacturers to reflect in average fuel economy 
those design changes expected to have comparable effects on in-use fuel 
economy;
    (5) The test procedure change is required by EPA or is a change 
initiated by EPA in its laboratory and is not a change implemented 
solely by a manufacturer in its own laboratory.
    (g)(1) Alcohol dual fuel automobiles and natural gas dual fuel 
automobiles must provide equal or greater energy efficiency while 
operating on alcohol or natural gas as while operating on gasoline or 
diesel fuel to obtain the CAFE credit determined in paragraphs (c)(2)(v) 
and (vi) of this section. The following equation must hold true:

Ealt/Epet  or = 1

Where:

Ealt = [FEalt/(NHValt 
xDalt)]x10 6 = energy efficiency while operating 
on alternative fuel rounded to the nearest 0.01 miles/million BTU.
Epet = [FEpet/(NHVpet 
xDpet)]x10 6 = energy efficiency while operating 
on gasoline or diesel (petroleum) fuel rounded to the nearest 0.01 
miles/million BTU.
FEalt is the fuel economy [miles/gallon for liquid fuels or 
miles/100 standard cubic feet for gaseous fuels] while operated on the 
alternative fuel as determined in Sec. 600.113;
FEpet is the fuel economy [miles/gallon] while operated on 
petroleum fuel (gasoline or diesel) as determined in Sec. 600.113;
NHValt is the net (lower) heating value [BTU/lb] of the 
alternative fuel;
NHVpet is the net (lower) heating value [BTU/lb] of the 
petroleum fuel;
Dalt is the density [lb/gallon for liquid fuels or lb/100 
standard cubic feet for gaseous fuels] of the alternative fuel;
Dpet is the density [lb/gallon] of the petroleum fuel.

    (i) The equation must hold true for both the city and highway fuel 
economy values for each test of each test vehicle.
    (ii)(A) The net heating value for alcohol fuels shall be determined 
per ASTM D 240 (Incorporated by reference as specified in Sec. 600.011-
93).
    (B) The density for alcohol fuels shall be determined per ASTM D 
1298 (Incorporated by reference as specified in Sec. 600.011-93).
    (iii) The net heating value and density of gasoline are to be 
determined by the manufacturer in accordance with Sec. 600.113(c).
    (2) For model years 1993 through 1995, alcohol dual fuel automobiles 
designed to operate on mixtures of alcohol and gasoline must, in 
addition to paragraph (g)(1) of this section, to obtain the CAFE credit 
determined in paragraphs (c)(2)(v) and (vi) of this section, provide 
equal or superior energy efficiency while operating on a mixture of 50% 
alcohol, 50% gasoline by volume, as while

[[Page 913]]

operating on gasoline fuel. The following equation must hold true:

E50/Egor=1

Where:

E50=[FE50/
(NHV50xD50)]x106=energy efficiency 
while operating on 50% alcohol, 50% gasoline rounded to the nearest 0.01 
miles/million BTU.
Eg=[FEg/
(NHVgxDg)]x106=energy efficiency while 
operating on gasoline fuel rounded to the nearest 0.01 miles/million 
BTU.
FE50 is the fuel economy [miles/gallon] while operated on 50% 
alcohol, 50% gasoline as determined in Sec. 600.113;
FEg is the fuel economy [miles/gallon] while operated on 
gasoline as determined in Sec. 600.113;
NHV50 is the net (lower) heating value [BTU/lb] of the 50/50 
blend;
NHVg is the net (lower) heating value [BTU/lb] of gasoline;
D50 is the density [lb/gallon] of the 50/50 blend;
Dg is the density [lb/gallon] of the gasoline.

    (i) To demonstrate that the equation holds true for each engine 
family, the manufacturer will:
    (A) Test one test vehicle in each engine family on both the city and 
highway cycles; or
    (B) In lieu of testing, provide a written statement attesting that 
equal or superior energy efficiency is attained while using a 50% 
alcohol, 50% gasoline mixture compared to using 100% gasoline.
    (ii)(A) The net heating value for the 50% alcohol, 50% gasoline 
mixture shall be determined by ASTM D 240 (Incorporated by reference as 
specified in Sec. 600.011-93).
    (B) The density for the 50% alcohol, 50% gasoline mixture shall be 
determined per ASTM D 1298 (Incorporated by reference as specified in 
Sec. 600.011-93).
    (iii) The net heating value and density of gasoline are to be 
determined by the manufacturer in accordance with Sec. 600.113(c).
    (3) Alcohol dual fuel passenger automobiles and natural gas dual 
fuel passenger automobiles manufactured during model years 1993 through 
2004 must meet the minimum driving range requirements established by the 
Secretary of Transportation (49 CFR part 538) to obtain the CAFE credit 
determined in paragraphs (c)(2)(v) and (vi) of this section.
    (h) For each of the model years 1993 through 2004, and for each 
category of automobile identified in paragraph (a) of this section, the 
maximum increase in average fuel economy determined in paragraph (c) of 
this section attributable to alcohol dual fuel automobiles and natural 
gas dual fuel automobiles shall be 1.2 miles per gallon or as provided 
for in paragraph (i) of this section.
    (1) The Administrator shall calculate the increase in average fuel 
economy to determine if the maximum increase provided in paragraph (h) 
of this section has been reached. The Administrator shall calculate the 
average fuel economy for each category of automobiles specified in 
paragraph (a) of this section by subtracting the average fuel economy 
values calculated in accordance with this section by assuming all 
alcohol dual fuel and natural gas dual fuel automobiles are operated 
exclusively on gasoline (or diesel) fuel from the average fuel economy 
values determined in paragraphs (b)(2)(vi), (b)(2)(vii), and (c) of this 
section. The difference is limited to the maximum increase specified in 
paragraph (h) of this section.
    (2) [Reserved]
    (i) In the event that the Secretary of Transportation lowers the 
corporate average fuel economy standard applicable to passenger 
automobiles below 27.5 miles per gallon for any model year during 1993 
through 2004, the maximum increase of 1.2 mpg per year specified in 
paragraph (h) of this section shall be reduced by the amount the 
standard was lowered, but not reduced below 0.7 mpg per year.

[59 FR 39659, Aug. 3, 1994]

    Effective Date Note: At 59 FR 39659, Aug. 3, 1994, Sec. 600.510-93 
was added. This section contains information collection and 
recordkeeping requirements and will not become effective until approval 
has been given by the Office of Management and Budget.