[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: 40CFR94.204]

[Page 613-614]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 94--CONTROL OF EMISSIONS FROM MARINE COMPRESSION-IGNITION ENGINES--
Table of Contents
 
                   Subpart C--Certification Provisions
 
Sec. 94.204  Designation of engine families.

    This section specifies the procedure and requirements for grouping 
of engines into engine families.
    (a) Manufacturers shall divide their engines into groupings of 
engines which are expected to have similar emission characteristics 
throughout their useful life. Each group shall be defined as a separate 
engine family.
    (b) For Category 1 marine engines, the following characteristics 
distinguish engine families:
    (1) Fuel;
    (2) Cooling method (including cooling medium);
    (3) Method of air aspiration;
    (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);
    (9) Cylinder arrangement (engines with aftertreatment devices only);
    (10) Fuel system configuration; and
    (11) Class (commercial or recreational).
    (c) For Category 2 marine engines, the following characteristics 
distinguish engine families:
    (1) The combustion cycle (e.g., diesel cycle);
    (2) The type of engine cooling employed (air-cooled or water-
cooled), and procedure(s) employed to maintain engine temperature within 
desired limits (thermostat, on-off radiator fan(s), radiator shutters, 
etc.);
    (3) The bore and stroke dimensions;
    (4) The approximate intake and exhaust event timing and duration 
(valve or port);
    (5) The location of the intake and exhaust valves (or ports);
    (6) The size of the intake and exhaust valves (or ports);
    (7) The overall injection, or as appropriate ignition, timing 
characteristics (i.e., the deviation of the timing curves from the 
optimal fuel economy timing curve must be similar in degree);
    (8) The combustion chamber configuration and the surface-to-volume 
ratio of the combustion chamber when the piston is at top dead center 
position, using nominal combustion chamber dimensions;
    (9) The location of the piston rings on the piston;
    (10) The method of air aspiration (turbocharged, supercharged, 
naturally aspirated, Roots blown);
    (11) The turbocharger or supercharger general performance 
characteristics (e.g., approximate boost pressure, approximate response 
time, approximate size relative to engine displacement);
    (12) The type of air inlet cooler (air-to-air, air-to-liquid, 
approximate degree to which inlet air is cooled);
    (13) The intake manifold induction port size and configuration;
    (14) The type of fuel and fuel system configuration;
    (15) The configuration of the fuel injectors and approximate 
injection pressure;

[[Page 614]]

    (16) The type of fuel injection system controls (i.e., mechanical or 
electronic);
    (17) The type of smoke control system;
    (18) The exhaust manifold port size and configuration; and
    (19) The type of exhaust aftertreatment system (oxidation catalyst, 
particulate trap), and characteristics of the aftertreatment system 
(catalyst loading, converter size vs engine size).
    (d) Upon request by the manufacturer, engines that are eligible to 
be included in the same engine family based on the criteria in paragraph 
(b) or (c) of this section may be divided into different engine 
families. This request must be accompanied by information the 
manufacturer believes supports the use of these different engine 
families.
    (e) Upon request by the manufacturer, the Administrator may allow 
engines that would be required to be grouped into separate engine 
families based on the criteria in paragraph (b) or (c) of this section 
to be grouped into a single engine family if the manufacturer 
demonstrates that the engines will have similar emission 
characteristics; however, recreational and commercial engines may not be 
grouped in the same engine family. This request must be accompanied by 
emission information supporting the appropriateness of such combined 
engine families.
    (f) Category 3 engines shall be grouped into engine families based 
on the criteria specified in Section 4.3 of the Annex VI Technical Code 
(incorporated by reference in Sec. 94.5), except as allowed in 
paragraphs (d) and (e) of this section.

[64 FR 73331, Dec. 29, 1999, as amended at 67 FR 68346, Nov. 8, 2002; 68 
FR 9785, Feb. 28, 2003]