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Tenneco introduced its oval-shaped gasoline
particulate filter (GPF) at the 2015 Frankfurt
Motor Show, designed for gasoline direct
injection (GDI) engines to reduce particulate
emissions in compliance with the Euro 6c
emissions regulations, which take effect in
September 2017.
Although GDI engines help improve fuel
economy and reduce CO2 emissions, they can
have higher particulate emissions due to shorter
in-cylinder fuel/air mixing times, compared with
multiport fuel injection engines. Advanced fuel
injection strategies are currently used to control
gasoline particulate emissions in-cylinder, but
they are designed for a particular emission test
cycle and may be less effective under real
driving conditions. Gasoline particulate filters
effectively control particulate emissions under
all operating conditions.
“The cut-off is currently 23 microns,” said
Frank Terres, executive director, core science,
advanced engineering and hot end development,
Tenneco Clean Air, “but there’s ongoing debate
that could see it reduced to ten and that will
create issues trying to engineer engine
developments to meet that criteria.”
GPFs use the same type of wall-flow
substrates as diesel particulate filters and can
be included in the exhaust system in addition to
the series three-way catalyst, or the catalyst
coating can be directly applied to the filter
substrate to form a four-way catalyst. Tenneco
has successfully adapted its canning technology
to accommodate these highly porous, fragile
substrates.
“The advantage GPFs enjoy over diesel
particulate filters is that, because they run at
550°-600°C, there’s no need for regeneration,
as that will occur under normal operating
conditions. It is, however, important to monitor
soot levels with a sensor via the engine
calibration as a precaution.” The first
applications are predicted to be “heavy cars
with small 1.6-1.8-litre capacity” engine.
8 www.automotivedesign.eu.com
September 2015
News
Delphi has created a joint venture with Tula
Technology to develop its ground-breaking
Dynamic Skip Fire (DSF) cylinder deactivation
system, claimed to be the industry’s first
individual cylinder deactivation system capable
of delivering improved fuel efficiency, whilst
managing engine noise, vibration and
harshness (NVH). In independent tests, DSF has
improved fuel efficiency by 17%, as measured
on a CAFE basis when compared to a vehicle
that does not have cylinder deactivation.
Tula’s revolutionary control approach
integrates advanced digital signal processing,
derived from consumer electronics technology,
with sophisticated powertrain controls, to
create what it described as the ultimate
variable displacement engine.
DSF technology does not rely on fixed
cylinder deactivation or switching between fixed
patterns. Rather, it continuously makes dynamic
firing decisions on an individual cylinder basis
to deliver the required engine torque for all
vehicle speeds and loads, while avoiding
unwanted vibration, but delivering optimal fuel
efficiency over a wide range of driving
conditions.
Matthew Younkins, Tula’s chief engineer
powertrain, explained that DSF can go from
“Zero to all cylinders, and any fraction between,
allowing you to match the number of cylinders
to the required torque need from the engine”.
Largely a software company, Tula has
developed a set of software algorithms that
allows the engine management control to
decide whether to fire or not fire every cylinder
Dynamic cylinder deactivation system revealed
Example torque request with conceptual skips and fires dynamically determined
1
.50 0.5 1.0 2.0 2.5 3.0
1.0
0
.5
0
T
ime (sec)
Skip
Fire
Torque demand
Particulate emissions targeted
ahead of Euro regs
Tenneco also launched two new dampers:
the CVSA2 (pictured) and its DRiV Smart
Damper. CVSA2 is Tenneco’s newest
generation of lightweight semi-active
dampers. It offers
significant improvements
in ride performance from
single valve technology,
as each damper features
two independent electro-
hydraulic valves for the
rebound and compression
motions to provide an
increased tuning range
for even greater vehicle
dynamics and higher
comfort levels.
It will be launched on
a luxury car later this year
and, said Rudi
Schurmans, executive
director, global
engineering, Tenneco Ride
Performance, bridges the
gap between the CVSAe
and CV2A2/Kinetic
dampers. DRiV Smart
Damper has a range of 2
to 4 digital valves for up
to 16 settings. Switching
time is limited by hydraulic
reaction to around 10 m/secs, but, added
Schurmans, power consumption is
minimised, as energy is only demanded
during compression or rebound.