[Code of Federal Regulations]
[Title 40, Volume 17]
[Revised as of July 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR86.129-80]
[Page 499-501]
TITLE 40--PROTECTION OF ENVIRONMENT
CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
PART 86_CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND
ENGINES--Table of Contents
Subpart B_Emission Regulations for 1977 and Later Model Year New Light-
Sec. 86.129-80 Road load power, test weight, and inertia weight class
determination.
(a) Flywheels, electrical or other means of simulating test weight
as shown in the following table shall be used. If the equivalent test
weight specified is not available on the dynamometer being used, the
next higher equivalent test weight (not to exceed 250 pounds) available
shall be used.
------------------------------------------------------------------------
Equivalent Inertia
Road load power at 50 mi/h-- Loaded vehicle test weight
light-duty trucks \1\ \2\ \3\ weight (pounds) weight class
(pounds) (pounds)
------------------------------------------------------------------------
Up to 1,062...... 1,000 1,000
1,063 to 1,187... 1,125 1,000
1,188 to 1,312... 1,250 1,250
1,313 to 1,437... 1,375 1,250
1,438 to 1,562... 1,500 1,500
1,563 to 1,687... 1,625 1,500
1,688 to 1,812... 1,750 1,750
1,813 to 1,937... 1,875 1,750
1,938 to 2,062... 2,000 2,000
2,063 to 2,187... 2,125 2,000
2,188 to 2,312... 2,250 2,250
2,313 to 2,437... 2,375 2,250
2,438 to 2,562... 2,500 2,500
[[Page 500]]
2,563 to 2,687... 2,625 2,500
2,688 to 2,812... 2,750 2,750
2,813 to 2,937... 2,875 2,750
2,938 to 3,062... 3,000 3,000
3,063 to 3,187... 3,125 3,000
3,188 to 3,312... 3,250 3,000
3,313 to 3,437... 3,375 3,500
3,438 to 3,562... 3,500 3,500
3,563 to 3,687... 3,625 3,500
3,688 to 3,812... 3,750 3,500
3,813 to 3,937... 3,875 4,000
3,938 to 4,125... 4,000 4,000
4,126 to 4,375... 4,250 4,000
4,376 to 4,625... 4,500 4,500
4,626 to 4,875... 4,750 4,500
4,876 to 5,125... 5,000 5,000
5,126 to 5,375... 5,250 5,000
5,376 to 5,750... 5,500 5,500
5,751 to 6,250... \4\ 6,000 6,000
6,251 to 6,750... 6,500 6,500
6,751 to 7,250... 7,000 7,000
7,251 to 7,750... 7,500 7,500
7,751 to 8,250... 8,000 8,000
8,251 to 8,750... 8,500 8,500
8,751 to 9,250... 9,000 9,000
9,251 to 9,750... 9,500 9,500
9,751 to 10,000.. 10,000 10,000
------------------------------------------------------------------------
\1\ For all light-duty trucks except vans, and for heavy duty vehicles
optionally certified as light-duty trucks, the road load power
(horsepower) at 50 mi/h shall be 0.58 times B (defined below) rounded
to the nearest \1/2\ hp.
\2\ For vans, the road load power at 50 mi/h (horsepower) shall be 0.50
times B (defined below) rounded to the nearest \1/2\ hp.
\3\ B is the basic vehicle frontal area (square foot) plus the
additional frontal area (square foot) of mirrors and optional
equipment exceeding 0.1 ft\2\ which are anticipated to be sold on more
than 33 pct of the car line. Frontal area measurements shall be
computed to the nearest 10th of a square foot using a method approved
in advanced by the administrator.
\4\ Light-duty vehicles over 5,750 lb loaded vehicle weight shall be
tested at a 5,500 lb equivalent test weight.
(b) Power absorption unit adjustment--light-duty trucks. (1) The
power absorption unit shall be adjusted to reproduce road load power at
50 mph true speed. The indicated road load power setting shall take into
account the dynamometer friction. The relationship between road load
(absorbed) power and indicated road load power for a particular
dynamometer shall be determined by the procedure outlined in Sec.
86.118 or other suitable means.
(2) The road load power listed in the table above shall be used or
the vehicle manufacturer may determine the road load power by an
alternate procedure requested by the manufacturer and approved in
advance by the Administrator.
(3) Where it is expected that more than 33 percent of a car line
within an engine-system combination will be equipped with air
conditioning per Sec. 86.080-24(g)(2), the road load power listed above
or as determined in paragraph (b)(2) of this section shall be increased
by 10 percent, up to a maximum increase of 1.4 horsepower, for testing
all test vehicies representing that car line within that engine-system
combination if those vehicles are intended to be offered with air
conditioning in production. The above increase for air conditioning
shall be added prior to rounding off as instructed by notes 2 and 3 of
the table.
(c) Power absorption unit adjustment--light-duty vehicles. (1) The
power absorption unit shall be adjusted to reproduce road load power at
50 mph true speed. The dynamometer power absorption shall take into
account the dynamometer friction, as discussed in Sec. 86.118.
(2) The dynamometer road load setting is determined from the
equivalent test weight, the reference frontal area, the body shape, the
vehicle protuberances, and the tire type by the following equations.
(i) For light-duty vehicles to be tested on a twin roll dynamometer.
Hp = aA + P + tW
where:
Hp = the dynamometer power absorber setting at 50 mph (horsepower).
A = the vehicle reference frontal area (ft\2\). The vehicle reference
frontal area is defined as the area of the orthogonal projection of the
vehicle; including tires and suspension components, but excluding
vehicle protuberances, onto a plane perpendicular to both the
longitudinal plane of the vehicle and the surface upon which the vehicle
is positioned. Measurements of this area shall be computed to the
nearest tenth of a square foot using a method approved in advance by the
Administrator.
P = the protuberance power correction factor from table 1 of this
paragraph (horsepower).
W = vehicle equivalent test weight (lbs) from the table in paragraph
(a).
a = 0.43 for fastback-shaped vehicles; = 0.50 for all other light duty
vehicles.
t = 0.0 for vehicles equipped with radial ply tires; = 3 x
10- 4 for all other vehicles.
A vehicle is considered to have a fastback shape if the rearward
projection of that portion of the rear surface (Ab) which
slopes at an angle of less than 20 degrees from the horizontal is at
least 25 percent as large as the vehicle reference frontal area. In
addition, this
[[Page 501]]
surface must be smooth, continuous, and free from any local transitions
greater than four degrees. An example of a fastback shape is presented
in Figure 1.
[GRAPHIC] [TIFF OMITTED] TR06OC93.161
Table I--Protuberance Power, P. Versus Total Protuberance Frontal Area,
Ap
------------------------------------------------------------------------
P
Ap (square foot) (horsepower)
------------------------------------------------------------------------
Ap<0.30................................................... 0.0
0.30 Ap<0.60.............................................. .40
0.60 Ap<0.90.............................................. .70
0.90 Ap<1.20.............................................. 1.00
1.20 Ap<1.50.............................................. 1.30
1.50 Ap<1.80.............................................. 1.60
1.80 Ap<2.10.............................................. 1.90
2.10 Ap<2.40.............................................. 2.20
2.40 Ap<2.70.............................................. 2.50
2.70 Ap<3.00.............................................. 2.80
3.00 Ap................................................... 3.10
------------------------------------------------------------------------
The protuberance frontal area, Ap, is defined in a manner analogous
to the definition of the vehicle reference frontal area, i.e., the total
area of the orthogonal projections of the vehicle mirrors, hood
ornaments, roof racks, and other protuberance onto a plane(s)
perpendicular to both the longitudinal plane of the vehicle and the
surface upon which the vehicle is positioned. A protuberance is defined
as any fixture attached to the vehicle protruding more than 1 inch from
the vehicle surface and having a projected area greater than 0.01 ft\2\
with the area calculated by a method approved in advance by the
Administrator. Included in the total protuberance frontal area shall be
all fixtures which occur as standard equipment. The area of any optional
equipment shall also be included if it is expected that more than 33
percent of the car line sold will be equipped with this option.
(ii) The dynamometer power absorber setting for light-duty vehicles
shall be rounded to the nearest 0.1 horsepower.
(iii) For light-duty vehicles to be tested on a single, large roll
dynamometer.
Hp = aA + P + (5.0 x 10 - 4 + 0.33t)W
All symbols in the above equation are defined in paragraph (c)(2)(i) of
this section. The rounding criteria of paragraph (c)(2)(i) also apply to
this paragraph.
(3) The road load power calculated above shall be used or the
vehicle manufacturer may determine the road load power by an alternate
procedure requested by the manufacturer and approved in advance by the
Administrator.
(4) Where it is expected that more than 33 percent of a car line
within an engine-system combination will be equipped with air
conditioning, per Sec. 86.080-24(g)(2), the road load power as
determined in paragraph (c) (2) or (3) of this section shall be
increased by 10 percent up to a maximum increment of 1.4 horsepower, for
testing all test vehicles of that car line within that engine-system
combination if those vehicles are intended to be offered with air
conditioning in production. This power increment shall be added to the
indicated dynamometer power absorption setting prior to rounding off
this value.
[42 FR 45653, Sept. 12, 1977, as amended at 43 FR 52921, Nov. 14, 1978]