[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: 40CFR86.092-24]

[Page 196-203]
 
                   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. 86.092-24  Test vehicles and engines.

    (a)(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 
shall be defined as a separate engine family.
    (2) To be classed in the same engine family, engines must be 
identical in all the following respects:

[[Page 197]]

    (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, etc.).
    (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 (e.g., 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 following features of each engine:
    (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 size 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 shall be 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 (a)(3) 
of this section, the Administrator will establish 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 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 following features of each engine:
    (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 shall 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:
    (i) Type of vapor storage device (e.g., 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 above, the 
Administrator will establish 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 Alternative 
Durability Program, the engine families covered by an application for 
certification shall be grouped based upon similar engine design and 
emission control system characteristics. Each of these groups shall 
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 following respects:
    (A) The combustion cycle.

[[Page 198]]

    (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 
multi-displacement 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 (a)(10) of 
this section.
    (12) The vehicles covered by an application for certification 
equipped with gasoline-fueled and 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 shall 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:
    (i) Method of fuel/air metering (i.e., carburetion versus fuel 
injection).
    (ii) Carburetor bowl fuel volume, within a 10 cc range.
    (14) For vehicles equipped with gasoline-fueled and methanol-fueled 
heavy-duty engines to be classified in the same evaporative emission 
control system, vehicles must be identical with respect to:
    (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 will establish evaporative emission family-
control system combinations for those vehicles based on features most 
related to their evaporative emission characteristics.
    (16) No 1992 or later model year heavy-duty engine which is to be 
used to generate emission credits for 1992 and later banking, trading 
and averaging programs may also utilize nonconformance penalties (NCPs). 
Use of an NCP thus becomes an engine family criterion.
    (i) Use of either a NOX or a particulate matter NCP by an 
engine family precludes that family from generating either 
NOX or particulate matter emission credits.
    (ii) If a manufacturer desires to use both banked credits and NCPs 
on an engine family, two separate engine families must be established. 
One engine family must consist of engines certified for only credit use 
following the procedure specified in this subpart. The other engine 
family must be certified for only NCP use following the procedure as 
specified in 40 CFR part 86, subpart L.
    (b) Emission data--(1) Emission-data vehicles. Paragraph (b)(1) of 
this section applies to light-duty vehicle and light-duty truck 
emission-data vehicles.
    (i) Vehicles will be chosen to be operated and tested for emission 
data based upon engine family groupings. Within each engine family, one 
test vehicle will be selected based on the following

[[Page 199]]

criteria: The Administrator shall select the vehicle with the heaviest 
equivalent test weight (including options) within the family. Then 
within that vehicle the Administrator shall select, 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 shall select one additional test vehicle from 
within each engine family. The vehicle selected shall be 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 including 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 
shall be 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 shall follow one of the following procedures:
    (A) The manufacturer will select for testing under high-altitude 
conditions the vehicle expected to exhibit the highest emissions from 
the nonexempt vehicles selected in accordance with paragraphs (b)(1) 
(ii), (iii), and (iv) of this section 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,
    (1) That all light-duty vehicles not exempt under Sec. 86.090-8(h) 
comply with the emission standards at high altitude; and
    (2) That light-duty trucks sold for principal use at designated 
high-altitude locations comply with the high-altitude emission 
requirements and that all light-duty trucks sold at low altitude, which 
are not exempt under Sec. 86.091-9(g)(2), are capable of being modified 
to meet high-altitude standards.
    (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 paragraphs (b)(1) (i), (ii), and (iv) of this 
section.
    (vii)(A) Vehicles of each evaporative emission family will be 
divided into evaporative emission control systems.
    (B) The Administrator will select the vehicle expected to exhibit 
the highest evaporative emissions, from within each evaporative family 
to be certified, 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 will select 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 shall follow one of the 
following procedures:
    (A) The manufacturer will select for testing under high-altitude 
conditions the one nonexempt vehicle previously selected under 
paragraphs (b)(1)(vii) (B) or (C) of this section which is expected to 
have the highest level of evaporative

[[Page 200]]

emissions when operated at high altitude or
    (B) In lieu of testing vehicles according to paragraph 
(b)(1)(viii)(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,
    (1) That all light-duty vehicles not exempt under Sec. 86.090-8(h) 
comply with the emission standards at high altitude, and
    (2) That light-duty trucks sold for principal use at designated 
high-altitude locations comply with the high-altitude emission 
requirements and that all light-duty trucks sold at low-altitude, which 
are not exempt under Sec. 86.091-9(g)(2), are capable of being modified 
to meet high-altitude standards.
    (ix) Vehicles selected under paragraph (b)(1)(v)(A) of this section 
may be used to satisfy the requirements of (b)(1)(viii)(A) of this 
section.
    (x) Light-duty trucks only: (A) The manufacturer may reconfigure any 
of the low-altitude emission-data vehicles to represent the vehicle 
configuration required to be tested at high altitude.
    (B) The manufacturer is not required to test the reconfigured 
vehicle at low altitude.
    (2) Otto-cycle heavy-duty emission-data engines. Paragraph (b)(2) of 
this section applies to Otto-cycle heavy-duty engines.
    (i)-(ii) [Reserved]
    (iii) The Administrator shall select 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 as follows:
    (A) The Administrator shall select one emission-data engine first 
based on the largest displacement within the engine family. Then within 
the largest displacement the Administrator shall select, in the order 
listed, highest fuel flow at the speed of maximum rated torque, the 
engine with the most advanced spark timing, no EGR or lowest EGR flow, 
and no air pump or lowest actual flow air pump.
    (B) The Administrator shall select one additional engine, from 
within each engine family. The engine selected shall be 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) 
(ii) and (iii) of this section do not represent each engine 
displacement-exhaust emission control system combination, then one 
engine of each engine displacement-exhaust emission control system 
combination not represented shall be selected by the Administrator.
    (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. Paragraph (b)(3) of 
this section applies to diesel heavy-duty emission-data vehicles.
    (i) Engines will be chosen to be run for emission data based upon 
engine family groupings. Within each engine family, the requirements of 
this paragraph 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 system 
combination shall 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 shall also be selected. The engine with the highest fuel feed per 
stroke will usually be selected.
    (iii) The Administrator may select a maximum of one additional 
engine

[[Page 201]]

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 paragraph 
(b)(3)(ii) and (iii) of this section.
    (c) Durability data--(1) Light-duty vehicle durability-data 
vehicles. Paragraph (c)(1) of this section applies to light-duty vehicle 
durability-data vehicles.
    (i) A durability-data vehicle will be selected by the Administrator 
to represent each engine-system combination. The vehicle selected shall 
be of the engine displacement with the largest projected sales volume of 
vehicles with that control-system combination in that engine family and 
will be designated by the Administration 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 shall be given to the Administrator no later than 30 
days following notification of the test fleet selection.
    (2) Light-duty trucks. Paragraph (c)(2) of this section applies to 
vehicles, engines, subsystems, or components used to establish exhaust 
emission deterioration factors for light-duty trucks.
    (i) The manufacturer shall 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 shall be 
selected so that their emissions deterioration characteristics may be 
expected to represent those of in-use vehicles, based on good 
engineering judgment.
    (ii) [Reserved]
    (3) Heavy-duty engines. Paragraph (c)(3) of this section applies to 
engines, subsystems, or components used to establish exhaust emission 
deterioration factors for heavy-duty engines.
    (i) The manufacturer shall 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 shall be selected so 
that their emissions 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. 86.092-26 (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 shall 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. 86.092-14 of this subpart for emission-
data vehicle selection and determination of deterioration factors. The 
deterioration factors shall be applied only to entire engine families.
    (f) 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

[[Page 202]]

the prior written approval of the Administrator, submit exhaust emission 
data and/or fuel 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. 86.091-23 has 
previously been submitted.
    (g)(1) 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.
    (2)(i) Where it is expected that more than 33 percent of a carline, 
within an engine-system combination, may be equipped with an item 
(whether that item is standard equipment or an option), the full 
estimated weight of that item shall be included in the curb weight 
computation of 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.
    (3)(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 shall 
actually be installed (unless excluded under paragraph (g)(3)(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)(3)(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 shall be included in the design curb 
weight and 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, shall be 
maintained by the manufacturer and shall be made available to the 
Administrator upon request.
    (4) 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 shall 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) Alternative Durability Program durability-data vehicles. This 
section applies to light-duty vehicle and light-duty truck durability-
data vehicles selected under the Alternative Durability Program 
described in Sec. 86.085-13.
    (1) 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 Alternative Durability 
Program procedures.
    (i) The Administrator shall select 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

[[Page 203]]

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 will be randomly 
selected from the manufacturer's production. The Administrator will make 
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 shall 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 shall 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 shall 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 will determine 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 shall select 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 shall select 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 of that design under the provisions of paragraph (h)(1) of this 
section.

[55 FR 7190, Feb. 28, 1990, as amended at 55 FR 30626, July 26, 1990]