Technical  Bulletin
              Diesel Oxidation Catalyst         National Clean  Diesel  Campaign
     Installation, Operation and Maintenance        www.epa.gov/cieandiesei
Pre-lnstallation
Prior to installing any retrofit device, engine inspection
and maintenance should be performed to ensure proper
engine operation, vehicle exhaust  system  integrity and
amount of lubrication oil  consumption.
Technology Selection

To select the best Diesel Particulate Filter (DPF)  for a
specific vehicle, it is necessary to identify:

 •  Vehicle Type: Highway or Nonroad

 •  Vehicle Class: School Bus, Class 8ATractor, Ferry,
   Locomotive, Forklift, etc

 •  Vehicle Specifications: Manufacturer, Model, Year

 •  Engine Specifications: Manufacturer, Model, Year,
   Displacement, Horsepower; Location, Turbo-charge,
   Exhaust Gas Recirculation (EGR)

 •  EPA Engine Family Name: Can be found on the engine's
   emission label and contains 11 or 12 characters such  as
   TCP7.2RZBDBRB or 3NVXHO466ANA
 •  Annual Miles Traveled (Highway) or Annual Hours of
   Operation (Nonroad)

 •  Engine-out PM emission levels and

 •  Engine duty cycle and the resultant exhaust temperatures.
The verified diesel retrofit technologies lists of the United
States  Environmental Protection Agency (EPA) and the
California Air Resources Board (GARB) define the specific
engine operating criteria that must be met to successfully
apply  a  particular  retrofit  technology  (www.epa.gov/
otaq/retrofit/verif-list.htm).  Installing  retrofits on engines
not included in the verification designation  may void the
engine and emission control component warranties, and
may  be considered tampering.


Exhaust Temperature Data Logging
To achieve verified levels of emissions reductions, DOCs
typically require a minimum exhaust gas temperature
of 150°C, this  is easily met on  a wide range  of engine
models, years,  and duty cycles.
Data logging must  be performed on each vehicle to
document  exhaust  temperatures.  If varying vehicle
routes  or sporadic work loads  are  used,  or significant
changes  in  ambient temperatures  are expected,  data
logging under different conditions may be  necessary to
accurately document duty cycle and the resultant exhaust
temperatures. Exhaust pipe insulation may be used to
retain heat. If insulation is used, data logging should be
performed with  insulation installed. Fleets should maintain
data  logging records for all vehicles for later reference.
          Diesel Oxidation Catalyst (DOC)
                  on Track Dozer
Installation
Installation may be performed by the retrofit supplier, or
the retrofit supplier may provide training to fleet personal
to perform installation.
Since a DOC typically weighs more and may be larger
than  the muffler, stronger clamps and brackets may be
required in place of those used with the original muffler.
Failure to  utilize appropriate hardware can result in a
mechanical failure of support brackets and damage to the
equipment.
In most applications, the DOC matches the dimensions of
the conventional muffler and can be installed as a muffler
replacement. In other cases the space available for DOC
installation on the vehicle or equipment is very restricted
and the DOC configuration must be  custom-designed.
Safety, visibility, and vibration issues may also need to be
addressed by a custom installation. The time required for
                                                                                       EPA-420-F-09-011
                                                                                           February 2009

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DOC installation will vary depending on the situation and is
generally one to three hours.
The DOC must be mounted  within a set distance of the
exhaust  manifold, as  specified  by  the manufacturer.
Exhaust pipe insulation may be used to retain heat.
Backpressure Monitoring

In most DOC retrofit  applications there is  no  need for
backpressure monitoring. However,  if the vehicle emits
extremely  high levels of PM and/or idles for  long periods
of time, an exhaust backpressure monitoring  and operator
notification system may be installed to notify the operator
when maintenance is needed.
Maintenance and Operation
Once properly installed, DOCs require little maintenance.
DOC manufacturers and product suppliers should provide
vehicle service technicians with training on proper retrofit
maintenance procedures.
Plugging is very rare, but it can occur in older, high-emitting
or poorly maintained vehicles and/or in situations where an
engine idles for a long period of time. As a result, the DOC
can be  overwhelmed with unburned fuel and lubricants
(ash) that must be removed by cleaning.
In general, cleaning requires removing the DOC from the
vehicle, heating it, and using compressed air combined
with a vacuum system to blow out the ash and capture  it
in a sealed container. Professional cleaning services are
available.  Highly  automated cleaning stations  are  also
becoming  available, allowing fleet service technicians to
perform cleaning on-site.
It is important to properly maintain vehicles and monitor
fuel and lubrication oil consumption. A bad fuel injector or
increased  oil consumption may be masked by a DOC. A
DOC may  be damaged by a  poorly maintained engine.

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