[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: 40CFR86.096-24]

[Page 345-352]
 
                   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 A_General Provisions for Emission Regulations for 1977 and Later 
 
Sec. 86.096-24  Test vehicles and engines.

    (a) General. This paragraph applies to the grouping of vehicles or 
engines into families.
    (1) The vehicles or engines covered by an application for 
certification will be divided into groupings of engines which are 
expected to have similar emission characteristics throughout their 
useful life. Each group of engines with similar emission characteristics 
is defined as a separate engine family.
    (2) To be classed in the same engine family, engines must be 
identical in all the respects listed in paragraphs (a)(2) (i) through 
(x) of this section.
    (i) The cylinder bore center-to-center dimensions.
    (ii)-(iii) [Reserved]
    (iv) The cylinder block configuration (air-cooled or water-cooled: 
L-6, 90 deg., V-8, and so forth).
    (v) The location of the intake and exhaust valves (or ports).
    (vi) The method of air aspiration.
    (vii) The combustion cycle.
    (viii) Catalytic converter characteristics.
    (ix) Thermal reactor characteristics.
    (x) Type of air inlet cooler (for example, intercoolers and after-
coolers) for diesel heavy-duty engines.
    (3)(i) Engines identical in all the respects listed in paragraph 
(a)(2) of this section may be further divided into different engine 
families if the Administrator determines that they may be expected to 
have different emission characteristics. This determination will be 
based upon a consideration of the features of each engine listed in 
paragraphs (a)(3)(i) (A) through (G) of this section.
    (A) The bore and stroke.
    (B) The surface-to-volume ratio of the nominally dimensioned 
cylinder at the top dead center positions.
    (C) The intake manifold induction port sizes and configuration.
    (D) The exhaust manifold port size and configuration.
    (E) The intake and exhaust valve sizes.
    (F) The fuel system.
    (G) The camshaft timing and ignition or injection timing 
characteristics.
    (ii) Light-duty trucks and heavy-duty engines produced in different 
model years and distinguishable in the respects listed in paragraph 
(a)(2) of this section are treated as belonging to a single engine 
family if the Administrator requires it, after determining that the 
engines may be expected to have similar emission deterioration 
characteristics.
    (4) Where engines are of a type which cannot be divided into engine 
families based upon the criteria listed in paragraphs (a)(2) and (3) of 
this section, the Administrator establishes families for those engines 
based upon those features most related to their emission 
characteristics. Engines that are eligible to be included in the same 
engine family based on the criteria in paragraphs (a)(2) and (a)(3)(i) 
of this section may be further divided into different

[[Page 346]]

engine families if the manufacturer determines that they may be expected 
to have different emission characteristics. This determination will be 
based upon a consideration of the features of each engine listed in 
paragraphs (a)(4) (i) through (iii) of this section.
    (i) The dimension from the center line of the crankshaft to the 
center line of the camshaft.
    (ii) The dimension from the center line of the crankshaft to the top 
of the cylinder block head face.
    (iii) The size of the intake and exhaust valves (or ports).
    (5) The gasoline-fueled and methanol-fueled light-duty vehicles and 
light-duty trucks covered by an application for certification will be 
divided into groupings which are expected to have similar evaporative 
emission characteristics throughout their useful life. Each group of 
vehicles with similar evaporative emission characteristics must be 
defined as a separate evaporative emission family.
    (6) For gasoline-fueled or methanol-fueled light-duty vehicles and 
light-duty trucks to be classed in the same evaporative emission family, 
vehicles must be similar with respect to the items listed in paragraphs 
(a)(6) (i) through (iii) of this section.
    (i) Type of vapor storage device (for example, canister, air 
cleaner, crankcase).
    (ii) Basic canister design.
    (iii) Fuel system.
    (7) Where vehicles are of a type which cannot be divided into 
evaporative emission families based on the criteria listed in paragraph 
(a)(2) of this section, the Administrator establishes families for those 
vehicles based upon the features most related to their evaporative 
emission characteristics.
    (8)(i) If the manufacturer elects to participate in the Production 
AMA Durability Program, the engine families covered by an application 
for certification must be grouped based upon similar engine design and 
emission control system characteristics. Each of these groups constitute 
a separate engine family group.
    (ii) To be classed in the same engine family group, engine families 
must contain engines identical in all of the respects listed in 
paragraphs (a)(8)(ii) (A) through (D) of this section.
    (A) The combustion cycle.
    (B) The cylinder block configuration (air-cooled or water-cooled: L-
6, V-8, rotary, etc.).
    (C) Displacement (engines of different displacement within 50 cubic 
inches or 15 percent of the largest displacement and contained within a 
multidisplacement engine family will be included in the same engine 
family group).
    (D) Catalytic converter usage and basic type (non-catalyst, 
oxidation catalyst only, three-way catalyst equipped).
    (9) Engine families identical in all respects listed in paragraph 
(a)(8) of this section may be further divided into different engine 
family groups if the Administrator determines that they are expected to 
have significantly different exhaust emission control system 
deterioration characteristics.
    (10) A manufacturer may request the Administrator to include in an 
engine family group engine families in addition to those grouped under 
the provisions of paragraph (a)(8) of this section. This request must be 
accompanied by information the manufacturer believes supports the 
inclusion of these additional engine families.
    (11) A manufacturer may combine into a single engine family group 
those light-duty vehicle and light-duty truck engine families which 
otherwise meet the requirements of paragraphs (a) (8) through (10) of 
this section.
    (12) Those vehicles covered by an application for certification 
which are equipped with gasoline-fueled or methanol-fueled heavy-duty 
engines will be divided into groupings of vehicles on the basis of 
physical features which are expected to affect evaporative emissions. 
Each group of vehicles with similar features must be defined as a 
separate evaporative emission family.
    (13) For gasoline-fueled or methanol-fueled heavy-duty vehicles to 
be classified in the same evaporative emission family, vehicles must be 
identical with respect to the items listed in paragraphs (a)(13) (i) and 
(ii) of this section.
    (i) Method of fuel/air metering (that is, carburetion versus fuel 
injection).

[[Page 347]]

    (ii) Carburetor bowl fuel volume, within a 10 cc range.
    (14) For vehicles equipped with gasoline-fueled or methanol-fueled 
heavy-duty engines to be classified in the same evaporative emission 
control system, vehicles must be identical with respect to the items 
listed in paragraphs (a)(14) (i) through (ix) of this section.
    (i) Method of vapor storage.
    (ii) Method of carburetor sealing.
    (iii) Method of air cleaner sealing.
    (iv) Vapor storage working capacity, within a 20g range.
    (v) Number of storage devices.
    (vi) Method of purging stored vapors.
    (vii) Method of venting the carburetor during both engine off and 
engine operation.
    (viii) Liquid fuel hose material.
    (ix) Vapor storage material.
    (15) Where vehicles equipped with gasoline-fueled or methanol-fueled 
heavy-duty engines are types which cannot be divided into evaporative 
emission family-control system combinations based on the criteria listed 
above, the Administrator establishes evaporative emission family-control 
system combinations for those vehicles based on features most related to 
their evaporative emission characteristics.
    (b) Emission data--(1) Light-duty vehicles and light-duty trucks. 
This paragraph applies to light-duty vehicle and light-duty truck 
emission data vehicles.
    (i) Vehicles are chosen to be operated and tested for emission data 
based upon engine family groupings. Within each engine family, one test 
vehicle is selected. The Administrator selects as the test vehicle the 
vehicle with the heaviest equivalent test weight (including options) 
within the family. If more than one vehicle meets this criterion, then 
within that vehicle grouping, the Administrator selects, in the order 
listed, the highest road-load power, largest displacement, the 
transmission with the highest numerical final gear ratio (including 
overdrive), the highest numerical axle ratio offered in that engine 
family, and the maximum fuel flow calibration.
    (ii) The Administrator selects one additional test vehicle from 
within each engine family. The additional vehicle selected is the 
vehicle expected to exhibit the highest emissions of those vehicles 
remaining in the engine family. If all vehicles within the engine family 
are similar, the Administrator may waive the requirements of this 
paragraph.
    (iii) Within an engine family and exhaust emission control system, 
the manufacturer may alter any emission data vehicle (or other vehicles 
such as current or previous model year emission data vehicles, fuel 
economy data vehicles, and development vehicles provided they meet 
emission data vehicles' protocol) to represent more than one selection 
under paragraph (b)(1) (i), (ii), (iv), or (vii) of this section.
    (iv) If the vehicles selected in accordance with paragraphs (b)(1) 
(i) and (ii) of this section do not represent each engine-system 
combination, then one vehicle of each engine-system combination not 
represented will be selected by the Administrator. The vehicle selected 
is the vehicle expected to exhibit the highest emissions of those 
vehicles remaining in the engine family.
    (v) For high-altitude exhaust emission compliance for each engine 
family, the manufacturer must follow one of the procedures described in 
paragraphs (b)(1)(v) (A) and (B) of this section.
    (A) The manufacturer must select for testing under high-altitude 
conditions the vehicle expected to exhibit the highest emissions from 
the nonexempt vehicles selected in accordance with Sec. 86.096-24(b)(1) 
(ii), (iii), and (iv); or
    (B) In lieu of testing vehicles according to paragraph (b)(1)(v)(A) 
of this section, a manufacturer may provide a statement in its 
application for certification that, based on the manufacturer's 
engineering evaluation of such high-altitude emission testing as the 
manufacturer deems appropriate, all light-duty vehicles and light-duty 
trucks not exempt under Sec. 86.090-8(h) or Sec. 86.094-9(h) comply 
with the emission standards at high altitude.
    (vi) If 90 percent or more of the engine family sales will be in 
California, a manufacturer may substitute emission data vehicles 
selected by the California Air Resources Board criteria for the 
selections specified in Sec. 86.096-24(b)(1) (i), (ii), and (iv).

[[Page 348]]

    (vii)(A) Vehicles of each evaporative emission family are divided 
into evaporative emission control systems.
    (B) The Administrator selects the vehicle expected to exhibit the 
highest evaporative emissions from within each evaporative family to be 
certified. This vehicle is selected from among the vehicles represented 
by the exhaust emission data selections for the engine family, unless 
evaporative testing has already been completed on the vehicle expected 
to exhibit the highest evaporative emissions for the evaporative family 
as part of another engine family's testing.
    (C) If the vehicles selected in accordance with paragraph 
(b)(1)(vii)(B) of this section do not represent each evaporative 
emission control system then the Administrator selects the highest 
expected evaporative emission vehicle from within the unrepresented 
evaporative system.
    (viii) For high-altitude evaporative emission compliance for each 
evaporative emission family, the manufacturer must follow one of the 
procedures listed in paragraphs (b)(1)(viii) (A) and (B) of this 
section.
    (A) The manufacturer will select for testing under high-altitude 
conditions the one nonexempt vehicle previously selected under paragraph 
(b)(1)(vii) (B) or (C) of this section which is expected to have the 
highest level of evaporative emissions when operated at high altitude; 
or
    (B) In lieu of testing vehicles according to Sec. 86.096-
24(b)(1)(viii)(A), a manufacturer may provide a statement in its 
application for certification that, based on the manufacturer's 
engineering evaluation of such high-altitude emission testing as the 
manufacturer deems appropriate, all light-duty vehicles and light-duty 
trucks not exempt under Sec. 86.090-8(h) or Sec. 86.094-9(h) comply 
with the emission standards at high altitude.
    (ix) Vehicles selected under paragraph (b)(1)(v)(A) of this section 
may be used to satisfy the requirements of paragraph (b)(1)(viii)(A) of 
this section.
    (x) [Reserved]
    (xi) For cold temperature CO exhaust emission compliance for each 
engine family, the Administrator will select for testing the vehicle 
expected to emit the highest emissions from the vehicles selected in 
accordance with paragraphs (b)(1) (i), (ii), (iii), and (iv) of this 
section. This vehicle is tested by the manufacturer in accordance with 
the test procedures in subpart C of this part or with alternative 
procedures requested by the manufacturer and approved in advance by the 
Administrator.
    (xii) For CST exhaust emission compliance for each engine family, 
the Administrator will select for testing one vehicle from among the 
vehicles selected in accordance with paragraphs (b)(1) (i) through (iv) 
of this section. This vehicle is tested by the manufacturer in 
accordance with the test procedures set forth in subpart O of this part.
    (2) Otto-cycle heavy-duty emission data engines. This paragraph 
applies to Otto-cycle heavy-duty emission data engines.
    (i)-(ii) [Reserved]
    (iii) The Administrator selects a maximum of two engines within each 
engine family based upon features indicating that they may have the 
highest emission levels of the engines in the engine family in 
accordance with the criteria described in paragraphs (b)(2)(iii) (A) and 
(B) of this section.
    (A) The Administrator selects one emission data engine first based 
on the largest displacement within the engine family. Then from those 
within the largest displacement the Administrator selects, in the order 
listed, the engine with the highest fuel flow at the speed of maximum 
rated torque, with the most advanced spark timing, with no EGR or lowest 
EGR flow, and with no air pump or with the lowest actual flow air pump.
    (B) The Administrator selects one additional engine from within each 
engine family. The engine selected is the engine expected to exhibit the 
highest emissions of those engines remaining in the engine family. If 
all engines within the engine family are similar, the Administrator may 
waive the requirements of this paragraph.
    (iv) If the engines selected in accordance with paragraph 
(b)(2)(iii) of this section do not represent each engine displacement-
exhaust emission control system combination, then the Administrator 
selects one engine of each engine

[[Page 349]]

displacement-exhaust emission control system combination not 
represented.
    (v) Within an engine family/displacement/control system combination, 
the manufacturer may alter any emission data engine (or other engine 
including current or previous model year emission data engines and 
development engines provided they meet the emission data engines' 
protocol) to represent more than one selection under paragraph 
(b)(2)(iii) of this section.
    (3) Diesel heavy-duty emission data engines. This paragraph applies 
to diesel-cycle heavy-duty emission data engines.
    (i) Engines will be chosen to be run for emission data based upon 
engine family groupings. Within each engine family, the requirements of 
paragraphs (b)(3) (i) through (iv) of this section must be met.
    (ii) Engines of each engine family will be divided into groups based 
upon their exhaust emission control systems. One engine of each engine 
system combination must be run for smoke emission data and gaseous 
emission data. Either the complete gaseous emission test or the complete 
smoke test may be conducted first. Within each combination, the engine 
that features the highest fuel feed per stroke, primarily at the speed 
of maximum rated torque and secondarily at rated speed, will usually be 
selected. If there are military engines with higher fuel rates than 
other engines in the same engine system combinations, then one military 
engine is also selected. The engine with the highest fuel feed per 
stroke is usually the one selected.
    (iii) The Administrator may select a maximum of one additional 
engine within each engine-system combination based upon features 
indicating that it may have the highest emission levels of the engines 
of that combination. In selecting this engine, the Administrator will 
consider such features as the injection system, fuel system, compression 
ratio, rated speed, rated horsepower, peak torque speed, and peak 
torque.
    (iv) Within an engine family control system combination, the 
manufacturer may alter any emission data engine (or other engine 
including current or previous model year emission data engines and 
development engines provided they meet the emission data engines' 
protocol) to represent more than one selection under paragraphs (b)(3) 
(ii) and (iii) of this section.
    (c) Durability data--(1) Light-duty vehicle durability data 
vehicles. This paragraph applies to light-duty vehicle durability data 
vehicles.
    (i) A durability data vehicle is selected by the Administrator to 
represent each engine-system combination. The vehicle selected must be 
of the engine displacement with the largest projected sales volume of 
vehicles with that control-system combination in that engine family and 
is designated by the Administrator as to transmission type, fuel system, 
inertia weight class, and test weight.
    (ii) A manufacturer may elect to operate and test additional 
vehicles to represent any engine-system combination. The additional 
vehicles must be of the same engine displacement, transmission type, 
fuel system, and inertia weight class as the vehicle selected for that 
engine-system combination in accordance with the provisions of paragraph 
(c)(1)(i) of this section. Notice of an intent to operate and test 
additional vehicles must be given to the Administrator no later than 30 
days following notification of the test fleet selection.
    (2) Light-duty trucks. This paragraph applies to vehicles, engines, 
subsystems, or components used to establish exhaust emission 
deterioration factors for light-duty trucks.
    (i) The manufacturer must select the vehicles, engines, subsystems, 
or components to be used to determine exhaust emission deterioration 
factors for each engine-family control system combination. Whether 
vehicles, engines, subsystems, or components are used, they must be 
selected so that their emission deterioration characteristics may be 
expected to represent those of in-use vehicles, based on good 
engineering judgment.
    (ii) [Reserved]
    (3) Heavy-duty engines. This paragraph applies to engines, 
subsystems, or components used to establish exhaust emission 
deterioration factors for heavy-duty engines.

[[Page 350]]

    (i) The manufacturer must select the engines, subsystems, or 
components to be used to determine exhaust emission deterioration 
factors for each engine-family control system combination. Whether 
engines, subsystems, or components are used, they must be selected so 
that their emission deterioration characteristics may be expected to 
represent those of in-use engines, based on good engineering judgment.
    (ii) [Reserved]
    (d) For purposes of testing under Sec. 86.094-26 (a)(9) or (b)(11), 
the Administrator may require additional emission data vehicles (or 
emission data engines) and durability data vehicles (light-duty vehicles 
only) identical in all material respects to vehicles (or engines) 
selected in accordance with paragraphs (b) and (c) of this section, 
provided that the number of vehicles (or engines) selected may not 
increase the size of either the emission data fleet or the durability 
data fleet by more than 20 percent or one vehicle (or engine), whichever 
is greater.
    (e)(1) [Reserved]
    (2) Any manufacturer may request to certify engine families with 
combined total sales of fewer than 10,000 light-duty vehicles, light-
duty trucks, heavy-duty vehicles, and heavy-duty engines utilizing the 
procedures contained in Sec. 86.094-14 for emission data vehicle 
selection and determination of deterioration factors. The deterioration 
factors are applied only to entire engine families.
    (f) Carryover and carryacross of durability and emission data. In 
lieu of testing an emission data or durability data vehicle (or engine) 
selected under paragraph (b) or (c) of this section, and submitting data 
therefore, a manufacturer may, with the prior written approval of the 
Administrator, submit exhaust emission data and/or evaporative emission 
data, as applicable on a similar vehicle (or engine) for which 
certification has previously been obtained or for which all applicable 
data required under Sec. 86.096-23 has previously been submitted.
    (g) This paragraph applies to light-duty vehicles and light-duty 
trucks, but does not apply to the production vehicles selected under 
paragraph (h) of this section.
    (1)(i) Where it is expected that more than 33 percent of a carline, 
within an engine-system combination, will be equipped with an item 
(whether that item is standard equipment or an option), the full 
estimated weight of that item must be included in the curb weight 
computation for each vehicle available with that item in that carline, 
within that engine-system combination.
    (ii) Where it is expected that 33 percent or less of the carline, 
within an engine-system combination, will be equipped with an item 
(whether that item is standard equipment or an option), no weight for 
that item will be added in computing the curb weight for any vehicle in 
that carline, within that engine-system combination, unless that item is 
standard equipment on the vehicle.
    (iii) In the case of mutually exclusive options, only the weight of 
the heavier option will be added in computing the curb weight.
    (iv) Optional equipment weighing less than three pounds per item 
need not be considered.
    (2)(i) Where it is expected that more than 33 percent of a carline, 
within an engine-system combination, will be equipped with an item 
(whether that item is standard equipment or an option) that can 
reasonably be expected to influence emissions, then such items must 
actually be installed (unless excluded under paragraph (g)(2)(ii) of 
this section) on all emission data and durability data vehicles of that 
carline, within that engine-system combination, on which the items are 
intended to be offered in production. Items that can reasonably be 
expected to influence emissions are: air conditioning, power steering, 
power brakes, and other items determined by the Administrator.
    (ii) If the manufacturer determines by test data or engineering 
evaluation that the actual installation of the optional equipment 
required by paragraph (g)(2)(i) of this section does not affect the 
emissions or fuel economy values, the optional equipment need not be 
installed on the test vehicle.
    (iii) The weight of the options must be included in the design curb 
weight

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and must also be represented in the weight of the test vehicles.
    (iv) The engineering evaluation, including any test data, used to 
support the deletion of optional equipment from test vehicles, must be 
maintained by the manufacturer and be made available to the 
Administrator upon request.
    (3) Where it is expected that 33 percent or less of a carline, 
within an engine-system combination, will be equipped with an item 
(whether that item is standard equipment or an option) that can 
reasonably be expected to influence emissions, that item may not be 
installed on any emission data vehicle or durability data vehicle of 
that carline, within that engine-system combination, unless that item is 
standard equipment on that vehicle or specifically required by the 
Administrator.
    (h) Production AMA Durability Program durability data vehicles. This 
paragraph applies to light-duty vehicle durability data vehicles 
selected under the Production AMA Durability Program described in Sec. 
86.094-13.
    (1) In order to update the durability data to be used to determine a 
deterioration factor for each engine family group, the Administrator 
will select durability data vehicles from the manufacturer's production 
line. Production vehicles will be selected from each model year's 
production for those vehicles certified using the Production AMA 
Durability Program procedures.
    (i) The Administrator selects the production durability data vehicle 
designs from the designs that the manufacturer offers for sale. For each 
model year and for each engine family group, the Administrator may 
select production durability data vehicle designs of equal number to the 
number of engine families within the engine family group, up to a 
maximum of three vehicles.
    (ii) The production durability data vehicles representing the 
designs selected in paragraph (h)(1)(i) of this section are randomly 
selected from the manufacturer's production. The Administrator makes 
these random selections unless the manufacturer (with prior approval of 
the Administrator) elects to make the random selections.
    (iii) The manufacturer may select additional production durability 
data vehicle designs from within the engine family group. The production 
durability data vehicles representing these designs must be randomly 
selected from the manufacturer's production in accordance with paragraph 
(h)(1)(ii) of this section.
    (iv) For each production durability data vehicle selected under 
paragraph (h)(1) of this section, the manufacturer must provide to the 
Administrator (before the vehicle is tested or begins service 
accumulation) the vehicle identification number. Before the vehicle 
begins service accumulation the manufacturer must also provide the 
Administrator with a description of the durability data vehicle as 
specified by the Administrator.
    (v) In lieu of testing a production durability data vehicle selected 
under paragraph (h)(1) of this section, and submitting data therefrom, a 
manufacturer may, with the prior written approval of the Administrator, 
submit exhaust emission data from a production vehicle of the same 
configuration for which all applicable data has previously been 
submitted.
    (2) If, within an existing engine family group, a manufacturer 
requests to certify vehicles of a new design, engine family, emission 
control system, or with any other durability-related design difference, 
the Administrator determines if the existing engine family group 
deterioration factor is appropriate for the new design. If the 
Administrator cannot make this determination or deems the deterioration 
factor not appropriate, the Administrator selects preproduction 
durability data vehicles under the provisions of paragraph (c) of this 
section. If vehicles are then certified using the new design, the 
Administrator may select production vehicles with the new design under 
the provisions of paragraph (h)(1) of this section.
    (3) If a manufacturer requests to certify vehicles of a new design 
that the Administrator determines are a new engine family group, the 
Administrator selects preproduction durability data vehicles under the 
provisions of paragraph (c) of this section. If vehicles are then 
certified using the new design, the

[[Page 352]]

Administrator may select production vehicles of that design under the 
provisions of paragraph (h)(1) of this section.

[58 FR 58417, Nov. 1, 1993]