february2022 - 20

Koukal said technicians should check and
adjust maintenance intervals as conditions
warrant. " If a technician cleans a DPF at 100,000
miles but it isn't too dirty yet, maybe the interval
can extend to 150,000 miles. The main thing is to
get on a routine that is based on that DPF's needs, "
he explained.
Tips on DPF cleaning
With an effective cleaning, Hough said it is not
unusual to restore a DPF to 90% capacity. The key
is making sure the DPF is cleaned as thoroughly
as possible.
" Sometimes a technician can get away with
just blowing a DPF out, " Koukal added. " But most
of the time, the filter needs to be put through a
regeneration in an oven. Baking a filter is what
breaks down the molecule of the soot particle,
which eases the process of cleaning it with air. "
According to Koukal, more fleets are now
demanding the aqueous method of cleaning.
" This is basically the same process as using air,
only the technician uses water, " Koukal explained.
» " Not all aftermarket
manufacturers are created
equal, " said Dave Jerman,
sales director for Roadwarrior.
" Fleets should do their
homework and talk to other
fleets. Don't just take it
from the manufacturer. "
Photo: Roadwarrior Inc.
" Cleaning a DPF with water is much more effective.
If you bake a DPF and use air, it may take two
or three rounds to get it clean. With the aqueous
method, there's a much higher chance of getting
it clean on the first try. "
Regardless of the method used, Koukal said the
technician's attention to detail is the critical factor.
" Our cleaning system is unique in that it's a
manual system, " Koukal said. " The technician
is actually inside the machine cleaning the DPF
with their own hands and eyes. This is different
than most of the equipment out there that
is automated. "
CDS operates a manufacturing division under
» Face plugging, caused by
carbon buildup, hurts DPF
and SCR performance.
Photo: Roadwarrior Inc.
" Baking a
filter is what
breaks down
the molecule
of the soot
particle,
which eases
the process
of cleaning
it with air. "
Ryan Koukal, chief
operating officer, CDS
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20 Fleet Maintenance | February 2022
1/6/22 8:57 AM
the brand name Enviromotive, which has been
making DPF cleaning equipment since 2008. The
company also licenses shops that have purchased
Enviromotive equipment.
According to Koukal, the hands-on aspect
helps provide another level of quality control.
When a filter comes out of an automated cleaning
machine, a certain amount of soot may have been
left behind that leads the technician to prematurely
condemn the filter. Because the technician
didn't physically perform the cleaning, there is
no recognition that the filter could be cleaned a
bit better.
" Depending on how a DPF is mounted or how
the exhaust flows through it, you can get problem
areas on a DPF, " Koukal explained. " A DPF
doesn't get dirty uniformly, so cleaning it uniformly
doesn't really make a lot of sense. A technician
may have to spend 15 minutes in a 5-inch-diameter
circle because that area has a lot of compacted
soot and ash. "
Koukal pointed out a few tests to help technicians
confirm that a DPF has been cleaned
adequately. The technician can weigh the DPF
before and after cleaning to measure how much
soot and ash was removed.
" Another effective test is what we call a tap test, "
Koukal said. " The technician takes the cleaned
DPF with the inlet side facing down, lifts it off the
ground an inch, and drops it. The DPF will bounce
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february2022

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