Fleet Operator's Tool Kit >>
Diesel Engine Retrofits
for Particulate Matter and
Diesel Oxidation Catalyst (DOC)
A diesel oxidation catalyst (DOC) is a flow through
device that consists of a canister containing a honeycomb-like
structure or substrate. The substrate has a large surface area that is
coated with an active catalyst layer. This layer contains a small,
well dispersed amount of precious metals such as platinum or
palladium. As the exhaust gases traverse the catalyst, carbon
monoxide, gaseous hydrocarbons and liquid hydrocarbon particles
(unburned fuel and oil) are oxidized, thereby reducing harmful
Oxidation Catalysts enable a chemical reaction that removes
approximately 20% of PM, and reduces HC by nearly 50%3. These
catalysts range in price from $1,000-$2,000, depending upon catalyst
composition and installation charges. DOCs can last upwards of 10
years, and require little to no maintenance once installed.
Installation of a DOC can take between 1-3 hours.
Diesel Particulate Filters (DPF)
of removing 60-90% of PM, HC, and CO when used correctly4. DPFs are
best suited for buses newer than 1995 in order to ensure that ideal
temperatures are reached in the exhaust stream to decompose particles
that accumulate in the filter. A DPF has a working life span between
7 and 15 years, and costs between $8,000-$10,0005. Applicants for 20
or more buses may apply for funding for particulate filter
regenerators, which must be used for all DPFs, including the ones that
will be used in new 2007 diesels.
Diesel Multi-Stage Filter
muffler removes 71-75% of PM, HC, and CO. The DMF is priced between
$6,000- $8,000, and requires minimal maintenance. This unit is
considered to be an effective compromise between the less expensive
DOC and the more efficient DPF5.
Crankcase Ventilation System (CCV)
crankcase is the source of the vast majority of pollution that impacts
students on the bus. Emissions from the engine compartment seep
through cracks and openings in windows and doors to create conditions
in which the particulate matter concentrations inside the bus may be
many times that of ambient conditions.
Crankcase filters ultimately reduce emissions of particulate matter to
the cabin by nearly 100%. Priced near $400-$700 each, CCVSs achieve
the highest emission reductions to the cabin per dollar. The CCVS
must be maintained on a regular basis by replacing the internal filter
at each oil change, at a cost of approximately $50.
CCVS can be used in conjunction with DMFs, DOCs, or DPFs. Both
tailpipe and crankcase retrofits are beneficial to students and the
public, reducing pollutants that reach the ambient air, as well as
reducing what seeps into the cabin of buses.
Diesel Particulate Filter Cleaning Systems
Shireman, General Manager for UHL Truck Sales, Louisville and
Palmyra, IN examines a Diesel Particulate Filter (DPF) ready for
cleaning. The market for DPF's has grown exponentially over the last
two years. They provide
a more affordable method for truck owners and operators to reduce
The FSX brand equipment includes the Test Bench,
Trap Blaster, Stage 2 Trap Burner and the Soot Sucker.
When DPF's do not burn the harmful particulate off
in normal operation, they are taken off and cleaned by a system such
as this. The cleaning
process takes 12 - 18 hours.
Only three of these DPF cleaning systems are
located in the Louisville region.
In the News
10.03.2012 - Clean Diesel Funding Announced
Who's Using Diesel
Engine Retrofits in Kentucky?
Ashland Independent School District
Corbin Independent Schools
Daviess County Public Schools
Elizabethtown Independent Schools
Floyd County Schools
Frankfort Independent Schools
Franklin County Public Schools
Gallatin County Schools
Grayson County Schools
Jefferson County Public Schools
Lincoln County School District
Livingston County Schools
Madison County Schools
Marion County Public Schools
Montgomery County Schools
Owsley County Schools
Pike County Schools
Pulaski County School System
Somerset Independent Schools
Spencer County Public Schools
Taylor County Schools
Trigg County Public Schools
Warren County Public Schools.
Who can Assist Me
with Diesel Engine Retrofits in Kentucky?