[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: 40CFR90.104]
[Page 176-178]
TITLE 40--PROTECTION OF ENVIRONMENT
CHAPTER I--ENVIRONMENTAL PROTECTION AGENCY (CONTINUED)
PART 90--CONTROL OF EMISSIONS FROM NONROAD SPARK-IGNITION ENGINES AT OR
BELOW 19 KILOWATTS--Table of Contents
Subpart B--Emission Standards and Certification Provisions
Sec. 90.104 Compliance with emission standards.
Paragraphs (a) through (c) of this section apply to Phase 1 engines
only. Paragraphs (d) through (h) of this section apply only to Phase 2
engines.
(a) If all test engines representing an engine family have emissions
less than or equal to each emission standard in a given engine
displacement class, that family complies with that class of emission
standards.
(b) If any test engine representing an engine family has emissions
greater than any one emission standard in a given engine displacement
class, that family will be deemed not in compliance with that class of
emission standards.
(c) If catalysts are used in an engine family, the engine
manufacturer must affirm that catalyst durability has been confirmed on
the basis of the evaluation procedure that is specified in subpart E of
this part.
(d) The exhaust emission standards (FELs, where applicable) for
Phase 2 engines set forth in this part apply to the emissions of the
engines for their full useful lives as determined pursuant to
Sec. 90.105.
(e) For all Phase 2 engines, if all test engines representing an
engine family have emissions, when properly tested according to
procedures in this part, less than or equal to each Phase 2 emission
standard (FEL, where applicable) in a given engine class and given model
year, when multiplicatively adjusted by the deterioration factor
determined in this section, that family complies with that class of
emission standards for purposes of certification. If any test engine
representing an engine family has emissions adjusted multiplicatively by
the deterioration factor determined in this section, greater than any
one emission standard (FEL, where applicable) for a given displacement
class, that family does not comply with that class of emission
standards.
(f) Each engine manufacturer must comply with all provisions of the
averaging, banking and trading program outlined in subpart C of this
part for each engine family participating in that program.
(g)(1) Small volume engine manufacturers and small volume engine
families may, at their option, take deterioration factors for
HC+NOX (NMHC+NOX) and CO from Table 1 or Table 2
of this paragraph (g), or they may calculate deterioration factors for
HC+NOX (NMHC+NOX) and CO according to the process
described in paragraph (h) of this section. For technologies that are
not addressed in Table 1 or Table 2 of this paragraph (g), the
manufacturer may ask the Administrator to assign a deterioration factor
prior to the time of certification. The provisions of this paragraph (g)
do not apply to Class I-A and Class I-B engines.
(2) Table 1 follows:
[[Page 177]]
Table 1: Nonhandheld Engine HC+NOX (NMHC+NOX) and CO Assigned Deterioration Factors for Small Volume
Manufacturers and Small Volume Engine Families
----------------------------------------------------------------------------------------------------------------
Side valve engines Overhead valve
---------------------- engines
Engine class ---------------------- Engines with
HC+NOX CO HC+NOX aftertreatment
(NMHC+NOX) (NMHC+NOX) CO
----------------------------------------------------------------------------------------------------------------
Class I................................. 2.1 1.1 1.5 1.1 Dfs must be calculated
using the formula in Sec.
90.104(g)(4).
Class II................................ 1.6 1.1 1.4 1.1
----------------------------------------------------------------------------------------------------------------
(3) Table 2 follows:
Table 2--Handheld Engine HC+NOX and CO Assigned Deterioration Factors for Small Volume Manufacturers and Small
Volume Engine Families
----------------------------------------------------------------------------------------------------------------
Two-stroke engines1 Four-stroke engines
Engine class ---------------------------------------------------- Engines with
HC+NOX CO HC+NOX CO aftertreatment
----------------------------------------------------------------------------------------------------------------
Class III........................... 1.1 1.1 1.5 1.1 Dfs must be calculated
using the formula in
Sec. 90.104(g)(4).
Class IV............................ 1.1 1.1 1.5 1.1
Class V............................. 1.1 1.1 1.5 1.1
----------------------------------------------------------------------------------------------------------------
1 Two-stroke technologies to which these assigned deterioration factors apply include conventional two-strokes,
compression wave designs, and stratified scavenging designs.
(4) Formula for calculating deterioration factors for engines with
aftertreatment:
DF = [(NE * EDF)-(CC * F)]/(NE-CC)
Where:
DF = deterioration factor.
NE = new engine emission levels prior to the catalyst (g/kW-hr)
EDF = deterioration factor for engines without catalyst as shown in
Table 1 or Table 2 of this paragraph (g)
CC = amount converted at 0 hours in g/kW-hr.
F = 0.8 for HC (NMHC), 0.0 for NOX, and 0.8 for CO for all
classes of engines.
(h)(1) Manufacturers shall obtain an assigned df or calculate a df,
as appropriate, for each regulated pollutant for all Phase 2 engine
families. Such dfs shall be used for certification, production line
testing, and Selective Enforcement Auditing.
(2) For engines not using assigned dfs from Table 1 or Table 2 of
paragraph (g) of this section, dfs shall be determined as follows:
(i) On at least one test engine representing the configuration
chosen to be the most likely to exceed HC+NOX
(NMHC+NOX) emission standards, (FELs where applicable), and
constructed to be representative of production engines pursuant to
Sec. 90.117, conduct full Federal test procedure emission testing
pursuant to the regulations of subpart E of this part at the number of
hours representing stabilized emissions pursuant to Sec. 90.118. If more
than one engine is tested, average the results and round to the same
number of decimal places contained in the applicable standard, expressed
to one additional significant figure;
(ii) Conduct such emission testing again following aging the engine.
The aging procedure should be designed to allow the manufacturer to
appropriately predict the in-use emission deterioration expected over
the useful life of the engine, taking into account the type of wear and
other deterioration mechanisms expected under typical consumer use which
could affect emissions performance. If more than one engine is tested,
average the results and round to the same number of decimal places
contained in the applicable standard, expressed to one additional
significant figure;
(iii) Divide the full useful life emissions (average emissions, if
applicable) for each regulated pollutant by the stabilized emissions
(average emissions, if applicable) and round to two significant figures.
The resulting number
[[Page 178]]
shall be the df, unless it is less than 1.0, in which case the df shall
be 1.0.
(iv) At the manufacturer's option additional emission test points
can be scheduled between the stabilized emission test point and the full
useful life test period. If intermediate tests are scheduled, the test
points must be evenly spaced over the full useful life period (plus or
minus 2 hours) and one such test point shall be at one-half of full
useful life (plus or minus 2 hours). For each pollutant
HC+NOX (NMHC+NOX) and CO, a line must be fitted to
the data points treating the initial test as occurring at hour zero, and
using the method of least-squares. The deterioration factor is the
calculated emissions durability period divided by the calculated
emissions at zero hours.
(3) EPA may reject a df if it has evidence that the df is not
appropriate for that family within 30 days of receipt from the
manufacturer. The manufacturer must retain actual emission test data to
support its choice of df and furnish that data to the Administrator upon
request. Manufacturers may request approval by the Administrator of
alternate procedures for determining deterioration. Any submitted df not
rejected by EPA within 30 days shall be deemed to have been approved.
(4) Calculated deterioration factors may cover families and model
years in addition to the one upon which they were generated if the
manufacturer submits a justification acceptable to the Administrator in
advance of certification that the affected engine families can be
reasonably expected to have similar emission deterioration
characteristics.
(5) Engine families that undergo running changes need not generate a
new df if the manufacturer submits a justification acceptable to the
Administrator concurrent with the running change that the affected
engine families can be reasonably expected to have similar emission
deterioration characteristics.
[60 FR 34598, July 3, 1995, as amended by 64 FR 15237, Mar. 30, 1999; 65
FR 24306, Apr. 25, 2000]