[Code of Federal Regulations]
[Title 40, Volume 18]
[Revised as of July 1, 2003]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR89.116]

[Page 58-59]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 89--CONTROL OF EMISSIONS FROM NEW AND IN-USE NONROAD COMPRESSION-IGNITION 
ENGINES--Table of Contents
 
       Subpart B--Emission Standards and Certification Provisions
 
Sec. 89.116  Engine families.

    (a) A manufacturer's product line is divided into engine families 
that are comprised of engines expected to have similar emission 
characteristics throughout their useful life periods.
    (b) The following characteristics distinguish engine families:
    (1) Fuel;
    (2) Cooling medium;
    (3) Method of air aspiration;

[[Page 59]]

    (4) Method of exhaust aftertreatment (for example, catalytic 
converter or particulate trap);
    (5) Combustion chamber design;
    (6) Bore;
    (7) Stroke;
    (8) Number of cylinders, (engines with aftertreatment devices only); 
and
    (9) Cylinder arrangement (engines with aftertreatment devices only).
    (c) Upon a showing by the manufacturer that the useful life period 
emission characteristics are expected to be similar, engines differing 
in one or more of the characteristics in paragraph (b) of this section 
may be grouped in the same engine family.
    (d) Upon a showing by the manufacturer that the expected useful life 
period emission characteristics will be different, engines identical in 
all the characteristics of paragraph (b) of this section may be divided 
into separate engine families.
    (e)(1) This paragraph (e) applies only to the placement of Tier 1 
engines with power ratings under 37 kW into engine families. The 
provisions of paragraphs (a) through (d) of this section also apply to 
these engines. The power categories referred to in this paragraph (e) 
are those for which separate standards or implementation dates are 
described in Sec. 89.112.
    (2) A manufacturer may place engines with power ratings in one power 
category into an engine family comprised of engines with power ratings 
in another power category, and consider all engines in the engine family 
as being in the latter power category for the purpose of determining 
compliance with the standards and other requirements of this part, 
subject to approval in advance by the Administrator and the following 
restrictions:
    (i) The engines that have power ratings outside the engine family's 
power category must constitute less than half of the engine family's 
sales in each model year for which the engine family grouping is made; 
and
    (ii) The engines that have power ratings outside the engine family's 
power category must have power ratings that are within ten percent of 
either of the two power levels that define the engine family's power 
category.
    (3) The restrictions described in paragraphs (e)(2)(i) and 
(e)(2)(ii) of this section do not apply if the emissions standards and 
other requirements of this part are at least as stringent for the engine 
family's power category as those of the other power categories 
containing engines in the engine family.

[59 FR 31335, June 17, 1994. Redesignated and amended at 63 FR 56995, 
57003, Oct. 23, 1998]