[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: 40CFR91.207]

[Page 314-316]
 
                   TITLE 40--PROTECTION OF ENVIRONMENT
 
         CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
 
PART 91--CONTROL OF EMISSIONS FROM MARINE SPARK-IGNITION ENGINES--Table of 
Contents
 
          Subpart C--Averaging, Banking, and Trading Provisions
 
Sec. 91.207  Credit calculation and manufacturer compliance with emission 
standards.

    (a) For each engine family, certification emission credits (positive 
or negative) are to be calculated according to the following equation 
and rounded, in accordance with ASTM E29-93a, to the nearest gram. ASTM 
E29-93a has been incorporated by reference. See Sec. 91.6. Consistent 
units are to be used throughout the equation. The following equation is 
used to determine hydrocarbon plus oxides of nitrogen credit status for 
an engine family, whether generating positive credits or negative 
credits:
[GRAPHIC] [TIFF OMITTED] TR04OC96.004

Where:
sales = the number of eligible sales tracked to the point of first 
retail sale for the given engine family during the model year. Annual 
production projections are used to project credit availability for 
initial certification. Actual sales volume is used in determining actual 
credits for end of-year compliance determination.
t = time in model years
Power = the average power of an engine family in kW (sales weighted). 
The power of each configuration is the rated output in kilowatts as 
determined by SAE J1228. This procedure has been incorporated by 
reference. See Sec. 91.6.

[[Page 315]]

max actual life = maximum actual life specific to the power rating and 
the application; max actual life = 2[mu]life
[mu]life = average actual life in years, specific to the 
power rating and the application as given below.
[GRAPHIC] [TIFF OMITTED] TR04OC96.054

Power = as defined above.
[mu]use = mean use in hours per year. For outboard engines,
[mu]use = 34.8 hrs /yr. For personal watercraft, 
[mu]use = 77.3 hrs/yr;
S(t) = cumulative fraction survived at time t;
S(t) = 
e-[lpar]tx0.906/[]life[rpar]4.0

STD = the current and applicable marine SI engine emission 
standard in grams per kilowatt hour as determined in Sec. 91.104.
FEL = the family emission limit for the engine family in grams per 
kilowatt hour.

    (b) Manufacturer compliance with the corporate average emission 
standard is determined on a corporate average basis at the end of each 
model year. A manufacturer is in compliance when the sum of positive and 
negative emission credits it holds is greater than or equal to zero, 
except as allowed under paragraph (c) of this section.
    (c)(1) Outboard Engines
    (i) For model year 1998, a manufacturer is in compliance when the 
sum of positive credits and negative emission credits it holds is 
greater than or equal to zero, including
    (A) Credits generated in MY 1998 exceed 70% of the negative credits 
generated in MY 1998. The remaining negative credits (up to 30% of the 
total negative credits) must be banked.
    (ii) For model year 1999, a manufacturer is in compliance when the 
positive credits generated in MY 1999 exceed the sum of 80% of the 
negative credits generated in MY 1999 and the negative credits banked in 
1998. The remaining negative credits (up to 20% of the total negative 
credits) must be banked.
    (iii) For model year 2000, a manufacturer is in compliance when the 
sum of positive and negative emission credits it holds is greater than 
or equal to zero, including
    (A) The negative credits banked in MY 1998 and MY 1999 and
    (B) Any adjustments to credits based on adjustments to FELs 
resulting from requirements in Sec. 91.118(h)(1)(i). Manufacturers do 
not have to recalculate compliance for model years 1998 and 1999.
    (2) Personal watercraft engines. (i) For model year 1999, a 
manufacturer is in compliance when the positive credits generated in MY 
1999 exceed 50% of the negative credits generated in MY 1999. The 
remaining negative credits (up to 50% of the total negative credits) 
must be banked.
    (ii) For model year 2000, a manufacturer is in compliance when the 
sum of positive and negative emission credits it holds is greater than 
or equal to zero, including
    (A) The negative credits banked in 1999 and
    (B) Any adjustments to credits based on adjustments to FELs 
resulting from requirements in Sec. 91.118(h)(1)(i). Manufacturers do 
not have to recalculate compliance for model year 1999.
    (d) When a manufacturer is not in compliance, the manufacturer will 
be in violation of these regulations and EPA may void ab initio the 
certificates of engine families for which the manufacturer has not 
obtained sufficient positive emission credits pursuant to Sec. 91.123.
    (e) Notwithstanding other provisions of this part, for model years 
beginning with model year 2000, a manufacturer having a negative credit 
balance during one period of up to four consecutive model years will not 
be considered to be in noncompliance in a model year up through and 
including model year 2009 where:
    (1) The manufacturer has a total annual production of engines 
subject to regulation under this part of 1000 or less; and
    (2) The manufacturer has not had a negative credit balance other 
than in three immediately preceding model years, except as permitted 
under paragraph (c) of this section; and
    (3) The FEL(s) of the family or families produced by the 
manufacturer are

[[Page 316]]

no higher than those of the corresponding family or families in the 
previous model year, except as allowed by the Administrator; and
    (4) The manufacturer submits a plan acceptable to the Administrator 
for coming into compliance with future model year standards including 
projected dates for the introduction or increased sales of engine 
families having FEL(s) below standard and projected dates for 
discontinuing or reducing sales of engines having FEL(s) above standard; 
and
    (5)(i) The manufacturer has set its FEL using emission testing as 
prescribed in subpart E of this part; or
    (ii) The manufacturer has set its FEL based on the equation and 
provisions of Sec. 91.118(h)(1)(i) and the manufacturer has submitted 
appropriate test data and revised its FEL(s) and recalculated its 
credits pursuant to the provisions of Sec. 91.118(h)(1); or
    (iii) The manufacturer has set its FEL using good engineering 
judgement, pursuant to the provisions of Sec. 91.118(h)(1)(ii) and 
(h)(2).

[64 FR 15239, Mar. 30, 1999, as amended at 65 FR 24314, Apr. 25, 2000]