40 C.F.R. § 610.21

Current through October 31, 2024
Section 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

Device categories Characteristics adversely affected
Fuel-Air System
Carburetors and fuel injection systemsAll.
Air-fuel ratio modifiers (e.g., air bleeds)All.
Atomization devices (acoustic and mechanical)All.
Vapor InjectorsAll.
Choke controls1, 2, and 4.
Air filters1, 2, and 4.
Fuel-air distribution systems (intake manifolds)1, 2, and 4.
Fuel pressure regulatorsAll.
Ignition System
Spark plugsAll.
Spark timing control systemsAll.
Spark duration control systems1, 4.
Spark energy sources1, 4.
Emission Control Systems
Exhaust gas recirculation (EGR) systemsAll.
After-treatment devices1, 2, and 4.
Drivetrain
Tires1.
Overdrive unitsAll.
Torque converter lockups1, 2, and 4.
Exhaust System
Headers1.
Tuned exhaust systems1.
Accessories
Cooling fan or cooling fan couplings1.
Cold start aids (e.g., engine heaters)1.
Lubrication
Oil filters3.
Vehicle Body
Aerodynamic drag reduction devices1.
Miscellaneous
Modification to valve timingAll.
Retrofit prechambersAll.
Fuel additivesAll.
Other miscellaneousPotentially 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.

40 C.F.R. §610.21

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