[Federal Register Volume 71, Number 44 (Tuesday, March 7, 2006)]
[Notices]
[Pages 11411-11413]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-3146]


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ENVIRONMENTAL PROTECTION AGENCY

[FRL-8041-3]


Control of Emissions From New and In-Use Highway Vehicles and 
Engines: Approval of New Scheduled Maintenance for Diesel Particulate 
Filters in Certain Applications

AGENCY: Environmental Protection Agency (EPA).

ACTION: Notice.

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SUMMARY: This notice announces that EPA has established a minimum 
interval of 80,000 miles (or 2400 hours) for the scheduled maintenance 
(cleaning) of diesel particulate filters used in some space-constrained 
truck applications. This minimum interval applies for model years 2007-
2009. Diesel particulate filter cleaning is considered critical 
emission-related maintenance.

FOR FURTHER INFORMATION CONTACT: David Dickinson, Compliance and 
Innovative Strategies Division, U.S. Environmental Protection Agency, 
Ariel Rios Building (6405J), 1200 Pennsylvania Avenue, NW., Washington, 
DC 20460. Telephone: (202) 343-9256. E-mail address: 
[email protected].

SUPPLEMENTARY INFORMATION: The Agency adopted new emission standards 
for heavy-duty diesel engines (HDDEs) in 2001 (66 FR 5002; January 18, 
2001). These standards will result in the introduction of new highly-
effective

[[Page 11412]]

control technologies, beginning with a phase-in over the 2007-09 model 
years. We expect that diesel particulate filters (DPFs), also called 
particulate traps, will be used to meet the new standards on HDDEs 
beginning in 2007.
    The Agency has received information from two heavy-duty engine 
manufacturers, Caterpillar, Inc. and DaimlerChrysler, indicating that 
it is technologically necessary to perform the cleaning of uncombusted 
deposits from DPFs in certain space-constrained truck applications more 
frequently than at the minimum maintenance interval prescribed for this 
activity in 40 CFR 86.004-25(b)(4)(iii). These applications use engines 
in the medium- and heavy-heavy-duty service classes. One reason this 
minimum interval is included in the regulations is to ensure that the 
control of emissions in use is not compromised by a manufacturer's 
overly frequent scheduling of emission-related maintenance. However, 
Sec.  86.094-25(b)(7)(ii) provides a process by which a manufacturer 
may request EPA approval of new scheduled maintenance, provided that 
such requests include supporting data and other substantiation for the 
recommended maintenance category (emission-related or non-emission-
related, critical or non-critical) and for the interval suggested for 
emission-related maintenance.
    The information received from the manufacturers pertains to the 
technologically necessary maintenance interval only and not to the 
appropriate maintenance category for DPF cleaning. The Agency has 
already determined that DPFs (particulate traps) are critical emission-
related components (see Sec.  86.004-25(b)(6)(i)(G)). Based on our 
review of the manufacturers' data, we have established a 
technologically necessary minimum maintenance interval of 80,000 miles 
(or 2400 hours) for DPF cleaning on a number of specialty vehicle 
applications, primarily in the medium-heavy-duty service class. None of 
these are applications with high sales volumes such as line-haul trucks 
or heavy-duty pick-up trucks.
    The truck applications covered by this notice are those in which 
the application's purpose imposes severe space constraints on the 
situating of exhaust system components. The DPF units being designed 
for use in 2007 vehicles are somewhat larger than the mufflers that 
they replace, and are sized such that they include sufficient excess 
filter volume to store the uncombustible ash that normally accumulates 
between cleanings. There are steps a manufacturer can take to minimize 
the DPF volume needed for ash build-up, such as through redesigning the 
engine to burn less lubricating oil, which in turn lowers the oil-
derived ash accumulation rate. Our review of the information provided 
by the manufacturers indicates that they have taken reasonable steps to 
limit ash build-up through such means, but that the resulting filter 
volumes are still too large to fit in the space available. However, a 
modest decrease in the filter volume reserved for ash build-up, made 
possible through the more frequent scheduling of routine cleaning, 
results in a DPF small enough to fit in these applications.
    Based on a review of the information provided by the manufacturers, 
we have concluded that the following truck applications have space 
constraints that warrant this shorter minimum allowable maintenance 
interval:
     Beverage truck;
     Maintenance truck with integral tool boxes;
     Garbage collection truck with hydraulic packing or picking 
apparatus;
     Fire truck;
     Airport refueler truck with exhaust directed toward the 
front of the truck;
     Utility truck with integral tool boxes and outrigger 
apparatus;
     Snow plow with under-chassis plow;
     Dump truck;
     Concrete mixer truck;
     Car hauler with integral open racks;
     Street sweeper;
     Armored car;
     Day cab truck (only those for which the entire DPF is 
located in front of the vertical plane established by the back side of 
the cab, and which furthermore do not have a rear seat).
    Any manufacturer of engines used in applications on this list could 
make use of this provision. This minimum interval applies only to 
vehicles with engines in the medium- and heavy-HDDE service classes 
(that is, with gross vehicle weight ratings above 19,500 lbs); no 
information was provided establishing such a need in the light-HDDE 
service class. The functional needs of the applications in this list 
typically preclude the routing of exhaust systems in a vertical stack 
or in the space behind the cab outside the frame rails. However, if any 
model year 2007-09 trucks in this list are in fact designed with a DPF 
mounted in a vertical stack or in the space behind the cab outside the 
frame rails, they will not be eligible for the 80,000 mile minimum 
interval because no case has been established for space limitations in 
such designs. Also, if an engine family is used in multiple truck 
applications, some of which are not included in the above list, the 
engines used in ``non-listed'' applications are not eligible for the 
80,000 mile minimum interval. For these engines the manufacturer must 
provide the owners with proper maintenance instructions that specify 
the applicable interval, as required under Sec.  86.087-38.
    In addition, to make use of this 80,000 mile minimum maintenance 
interval, manufacturers must indicate their intention in the 
applications for certification. They must also state their intent to 
help ensure that the smaller DPFs will only be installed in the 
approved truck applications, and must show the reasonable likelihood of 
the maintenance being performed in use as required under CFR Sec.  
86.004-25(b)(6), with consideration given to the shorter specified 
maintenance interval.
    Although the 80,000 mile interval is significantly shorter than the 
nominal 150,000 mile interval that would otherwise apply, there are a 
number of factors helping to provide confidence that this maintenance 
is as likely to be properly performed on schedule. First, the covered 
vehicle applications are commercial in nature. In general, routine 
maintenance on commercial vehicles is more likely to be performed on 
schedule to avoid the costly job delays, customer dissatisfaction, 
workforce idling, and emergency repairs arising from component failures 
in the field, and also of course to avoid jeopardizing warranty 
coverage. Second, many of these vehicles are not typically driven over 
large distances during the course of a year. As a result, filter 
cleaning at 80,000 mile (or 2400 hour) intervals is not likely to be so 
frequent as to irritate vehicle operators or hamper them from 
accomplishing their daily tasks, which might in turn cause them to 
neglect the needed cleaning. Third, the continued build-up of ash from 
a lack of cleaning would increase engine backpressure, resulting in 
loss of power, poor fuel economy, and eventually vehicle stalling. 
Commercial vehicle drivers and maintenance technicians are likely to be 
well aware of these serious consequences from neglected maintenance. 
Fourth, we expect that most or all manufacturers will provide a visible 
signal or some similar indication to inform a driver of the need for 
filter cleaning, thus reducing reliance on manual tracking of vehicle 
mileage to provide the needed reminder that maintenance is due. 
Finally, DPF cleaning is covered under the ``critical emission-related 
components'' provision of 40 CFR 86.004-25(b)(6). Thus, manufacturers 
are ``required to show the reasonable likelihood of such maintenance 
being performed in use.'' A

[[Page 11413]]

number of means are available to make this showing, including the 
visible signal indication mentioned above.
    We are limiting this determination to the 2007-2009 model years for 
two reasons. First, we believe that the problem of redesigning the 
covered vehicles to accommodate DPFs, though a matter of technological 
necessity, arises largely from the time remaining before 2007, which 
precludes manufacturers performing an extensive redesign of these 
space-constrained vehicles to accommodate the DPFs. Given more time, 
the somewhat larger DPFs needed to achieve 150,000 mile cleaning 
intervals could be accommodated in vehicle designs without compromising 
mission objectives.
    Second, the compliance strategies being chosen by the engine 
manufacturers generally entail a two step approach to meeting the new 
NOX standards, such that NOX aftertreatment 
devices will not be employed until 2010, and engine/vehicle designs 
will remain stable through the 2007-2009 phase-in period. Although the 
technology choices for 2010 NOX control have not yet been 
made, we think it likely that new exhaust system space requirements 
will be added to those entailed by the use of DPFs in 2007. Given that 
three additional years of leadtime are available before 2010, and that 
adjusting the DPF cleaning interval can contribute, at best, only 
modest relief to these space constraint problems, we expect 
manufacturers to rely on broader vehicle redesigns rather than on 
shorter cleaning intervals to resolve any such problems. Should that 
process identify applications in which shorter DPF cleaning intervals 
are still technologically necessary for 2010 and later heavy-duty 
vehicles, we would expect manufacturers to take this up with us in a 
timely manner.

    Dated: February 27, 2006.
William L. Wehrum,
Acting Assistant Administrator, Office of Air and Radiation.
 [FR Doc. E6-3146 Filed 3-6-06; 8:45 am]
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