(14) ``Lean-on-cruise'' calibration strategies. (i) For Tier 2 and
interim non-Tier 2 vehicles, the manufacturer must state in the
Application for Certification whether any ``lean-on-cruise'' strategies
are incorporated into the vehicle design. A ``lean-on-cruise'' air-fuel
calibration strategy is defined as the use of an air-fuel ratio
significantly greater than stoichiometry, during non-deceleration
conditions at speeds above 40 mph. ``Lean-on-cruise'' air-fuel
calibration strategies must not be employed during vehicle operation in
normal driving conditions, including A/C usage, unless at least one of
the following conditions is met:
(A) Such strategies are substantially employed during the FTP or
SFTP;
(B) Such strategies are demonstrated not to significantly reduce
vehicle NMHC+NOX emission control effectiveness over the
operating conditions in which they are employed; or
(C) Such strategies are demonstrated to be necessary to protect the
vehicle occupants, engine, or emission control hardware.
(ii) If the manufacturer proposes to use a ``lean-on-cruise''
calibration strategy, the manufacturer must specify the circumstances
under which such a calibration would be used, and the reason or reasons
for the proposed use of such a calibration.
* * * * *
(o) Unless otherwise approved by the Administrator, manufacturers
must measure NMOG emissions in accordance with the California Non-
Methane Organic Gas Test Procedures. These procedures are incorporated
by reference (see Sec. 86.1).
(p) For gasoline and diesel-fueled Tier 2 and interim non-Tier 2
vehicles, manufacturers may measure non-methane hydrocarbons (NMHC) in
lieu of NMOG. Manufacturers must multiply NMHC measurements from
gasoline vehicles by an adjustment factor of 1.04 before comparing with
the NMOG standard to determine compliance with that standard.
Manufacturers may use other factors to adjust NMHC results to more
properly represent NMOG results. Such factors must be based upon
comparative testing of NMOG and NMHC emissions and be approved in
advance by the Administrator.
http://www.epa.gov/fedrgstr/EPA-AIR/...ay-10/a19d.htm