of the electronics are then mounted
remotely, meaning there is no exposure to high temperatures or severe
Sappok said the technology is suitable for any vehicle or machine that
has a DPF and added that Filter
Sensing Technologies is also studying gasoline particulate filter applications with light-duty OEMs.
Filter Sensing Technologies received funding from the U.S. Dept.
of Energy (DOE) and the National
Science Foundation to help develop
the system. The DOE’s field tests on
the technology are slated to end next
summer, Sappok said. The system is
being tested on a fleet of Volvo and
Mack trucks operated by the New
York City Dept. of Sanitation.
The system also would have benefits for machines operating on biodiesel fuels, Sappok said.
“Right now, if you’re running some-
thing like a B20 that’s producing
slightly lower soot emissions, the
timer-based regen is going to kick in
regardless of how much soot is on
the DPF,” Sappok said. “By using
a cleaner fuel that’s producing less
soot, you can further extend the
regen intervals in our case since
we’re determining the regen by how
much soot is actually in the DPF.”
Oak Ridge National Laboratory
is running tests that compare DPF
regeneration intervals with standard
ultralow sulfur diesel, B20, as well as
an extreme case, B100 fuel, he said.
Sappok said by enabling less-frequent — and likely shorter —
regenerations, the system also limits
the time the DPF is exposed to the
very high temperatures needed to
remove the soot. That, in turn, would
reduce some of the thermal fatigue
that can affect the filter integrity over
time, so there’s potential to extend
the useful life of the DPF.
“The other thing we are able to
do with the sensing technology is to
detect not only the amount of soot in
the DPF, but also the amount of ash
that builds up over time,” he said. “We
can detect those simultaneously.”
Sappok said measuring ash build-
up based on pressure drop alone
is very difficult because ash essen-
tially increases pressure drop the
same way that soot does. For the
most part, OEMs now specify ash-
removal intervals that are based on
time or mileage.
“So filters are coming off to be
cleaned whether they need it or
not,” Sappok said. “By measuring the
amount of ash in the filter directly,
you could also alert the operator
when the filter needs to be cleaned.”
If a machine has an engine that
consumes little oil and creates
very little ash in the DPF, the ash-
cleaning interval could be extended.
Conversely, if for some reason a
machine is experiencing high levels
of ash relatively quickly, the operator
would have that information as well
so the filter could be cleaned more
appropriately, Sappok said.
With fewer regenerations, Sappok
said that the system can help achieve
fuel savings, something that OEMs
can tout to end users. And by better sensing what’s happening in the
DPF, OEMs and DPF manufacturers
can fine-tune systems and potentially save money.
“A lot of aftertreatment systems
are slightly oversized,” he said.
“They are using bigger filters, they’re
loading more precious metal catalyst
onto the filters than they otherwise
might need if they had a better measurement of what was happening on
“Now that DPFs have been out in
the field, the focus has shifted from
making sure that they work to bringing the cost down, reducing size
and improving packaging. Improved
sensing enables the use of less
expensive DPF materials, reduce
catalyst loadings, use smaller-sized
filters, all of which can have a significant cost savings to the OEMs.” dp
The company’s system is capable of operating with either
a single antenna or dual antennas. The size of the antenna
is similar to a conventional exhaust temperature sensor.