[Code of Federal Regulations]
[Title 40, Volume 29]
[Revised as of July 1, 2007]
From the U.S. Government Printing Office via GPO Access
[CITE: 40CFR610.21]

[Page 1002]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 610_FUEL ECONOMY RETROFIT DEVICES--Table of Contents
 
       Subpart B_Evaluation Criteria for the Preliminary Analysis
 
Sec. 610.21  Device functional category and vehicle system effects.

    (a) The devices evaluated in this program are organized into 
categories for purposes of definition and establishment of evaluation 
criteria and test procedures, and to indicate which vehicle functional 
characteristics (other than fuel economy) may be adversely affected by 
installation or use of the device.
    (b) A device's category will be based on:
    (1) Engineering principles governing operation of the device;
    (2) Interaction between the device and specific vehicle/engine 
operating characteristics; and
    (3) Constraints with respect to vehicle applicability of the device.
    (c) The device categories and the vehicle functional characteristics 
which may be adversely affected are noted for each device category in 
Table I. The notation for each characteristic is as follows:

Exhaust emissions......................................................1
Driveability...........................................................2
Durability.............................................................3
Performance............................................................4

                                 Table 1
------------------------------------------------------------------------
                                             Characteristics adversely
            Device categories                         affected
------------------------------------------------------------------------
             Fuel-Air System

Carburetors and fuel injection systems...  All.
Air-fuel ratio modifiers (e.g., air        All.
 bleeds).
Atomization devices (acoustic and          All.
 mechanical).
Vapor Injectors..........................  All.
Choke controls...........................  1, 2, and 4.
Air filters..............................  1, 2, and 4.
Fuel-air distribution systems (intake      1, 2, and 4.
 manifolds).
Fuel pressure regulators.................  All.

             Ignition System

Spark plugs..............................  All.
Spark timing control systems.............  All.
Spark duration control systems...........  1, 4.
Spark energy sources.....................  1, 4.

         Emission Control Systems

Exhaust gas recirculation (EGR) systems..  All.
After-treatment devices..................  1, 2, and 4.

                Drivetrain

Tires....................................  1.
Overdrive units..........................  All.
Torque converter lockups.................  1, 2, and 4.

              Exhaust System

Headers..................................  1.
Tuned exhaust systems....................  1.

               Accessories

Cooling fan or cooling fan couplings.....  1.
Cold start aids (e.g., engine heaters)...  1.

               Lubrication

Oil filters..............................  3.

               Vehicle Body

Aerodynamic drag reduction devices.......  1.

              Miscellaneous

Modification to valve timing.............  All.
Retrofit prechambers.....................  All.
Fuel additives...........................  All.
Other miscellaneous......................  Potentially all.
------------------------------------------------------------------------

    (d) In the absence of sufficient information from the device 
manufacturer on this topic or if the Administrator's preliminary 
analysis indicates that testing is necessary to determine the nature or 
extent of possible adverse effects of device installation and use on 
vehicle operation and performance, the Administrator will require such 
tests to be conducted prior to the publication of a complete evaluation 
of the device.

[44 FR 17946, Mar. 23, 1979, as amended at 49 FR 18489, May 1, 1984]