may2021 - 20

»An example of face-plugging due to an
aftertreatment system that hadn't been
working properly. Face-plugging refers to
a heavy buildup of carbon on the inlet side
of a DOC (diesel oxidation catalyst). Randy
Griffith, director of sales at Emission & Cooling
Solutions (E+CS), said face-plugging like this
would likely be traced to an upstream issue
such as a leaking turbo or EGR, or something
as simple as a lack of regular maintenance.
Photo courtesy of E+CS

minimal expense for a fleet, Griffith says it has
risen to the top of the list behind fuel, oil, and tires.
" Aftertreatment components are expensive, "
Griffith said. " Without knowledge of the system
and the proper diagnostic equipment, a fleet can
easily spend tens of thousands of dollars to fix
one system. Furthermore, fleets will typically deal
with an ongoing occurrence until the root cause
is repaired correctly. "

How some fleets illegally bypass
aftertreatment systems
Given all of these hurdles, some smaller fleets
have gone the way of removing entire systems
from a truck. This creates both environmental and
legal issues. Additionally, E+CS' Griffith says there
can also be some drivability issues that cannot be
repaired through the typical OE dealer channel.
" From my understanding, an OE dealership
will not touch a truck in which the aftertreatment
systems have been tampered with, " he pointed
out. " This leaves fleets with very little support if
there is a major issue down the road. "
Nonetheless, some fleets make the ill-advised
decision to tamper.
Griffith stresses the fact that E+CS has never
engaged in the removal or bypassing of an aftertreatment system. " We are in the business of

Improving aftertreatment
systems in vocational
applications
Len Copeland, product marketing manager
for Detroit Products, said a few key updates
have been made to Detroit engines to improve
the aftertreatment system performance of
heavy duty trucks in vocational applications.
* An " auto elevate " feature eliminates hydrocarbon buildup in the aftertreatment
system. Exhaust temperatures are temporarily increased during a slow ramp-up of
RPMs while idling for a short period of time.
Copeland also pointed out that this functionality will not interfere with PTO operation.
* For select applications, passive regens
are possible during PTO operation,
allowing uninterrupted use.
* With Detroit's DD15 Gen 5 engine update,
ThermoCoasting and Asymmetric Injection
at idle help to further maintain exhaust
temperatures in low-load situations.

20 Fleet Maintenance | May 2021

cleaning and repairing aftertreatment systems
as well as providing aftermarket products to
keep systems intact as they were intended to be, "
Griffith emphasized. That said, his many years in
the industry have exposed Griffith to a story or
two. Plus, his knowledge of engines and aftertreatment systems allows him to see where tampering
could take place.
" I was in a shop in early April where a customer brought in a truck with a head gasket issue, "
Griffith related. " When the technician went to
clean the filters, he found that the DPF had been
drilled out due to contamination. According to
the owner-operator of the truck, he had no idea
the truck had been deleted when he'd recently
purchased it. "
Drilling out the DPF is a common way people
delete their aftertreatment systems. This is generally done with a hole saw to make large passages through the filter media so it can bypass the
filtration. Generally, this will cause aftertreatment
codes which will then need to be either left in the
system or programmed out of the system.
Another bypass method Griffith has heard
about is the installation of block-off plates in place
of the exhaust gas circulation (EGR) cooler. That
keeps the system from recirculating the exhaust
back into the engine. " This is common on early
aftertreatment systems, " Griffith added.

" When it comes to a
person or company
actually tampering
with a vehicle, there
are many consequences
including voiding of
the warranty, hefty
fines from the EPA
(Environmental
Protection Agency) or
CARB (California Air
Resources Board), and
possible imprisonment. "
Johan Agebrand, director of product
marketing for Volvo Trucks North America

may2021

Table of Contents for the Digital Edition of may2021