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Looming CO2 legislation and
mandatory rules on fuel economy provide the automotive industry
continued pressure to bring down fuel consumption quickly. The time
until strict rules will be in place is only six years in Europe
(2014) and even less in the U.S. According to the Green Diesel
Platform, this challenge means using existing, validated
technologies to bring down CO2 emissions quickly in conventional,
mass-production cars. The diesel engine, with its high level of fuel
efficiency, can help automakers meet the greenhouse gas legislation
limits; however, the issues of particulate matter (PM) and oxides of
nitrogen (NOx) emissions must also be addressed. The minimum target
is to bring diesel’s local pollution down to the same level as the
gasoline engine’s.
In
Europe, where about 50% of all new cars are equipped with a diesel
engine, much of the progress toward achieving the first ACEA target
of 140 g of CO2 per km (225 g/mi) by 2008 owes to the increasing
share of downsized turbocharged diesel engines. Despite an
increasing trend toward the use of powerful, large-capacity diesel
engines for premium sedans and large SUVs, the same underlying logic
still applies. Modern direct- injection, turbocharged diesel engines
better a naturally aspirated gasoline engine’s fuel efficiency by
roughly 30%.
Once the diesel engine is
turned into a clean machine, it offers a potential for lowering
carbon-dioxide fleet emissions. French carmaker Peugeot spearheaded
the use of the diesel particulate filter (DPF) with an additive-based
solution. Peugeot was the first company to equip its vehicles with
DPFs in 2000 when the rest of the European car industry,
particularly the German automakers, focused solely on bringing down
engine-out emissions. The massive success Peugeot achieved by
removing at least one of diesel’s
two “poison pills” forced the whole industry to review the situation.
By now, the DPF is nearly standard in new diesel cars, though it
will not be mandatory in the EU until the Euro 5 standard takes
effect in 2009. The next step will be the installation of selective
catalytic reduction (SCR) systems to achieve the NOx emissions
levels required by the currently debated Euro 6 standard, which will
be implemented in 2014.
The growing international
tendency to equip cars with diesel engines is the motivation for the
Green Diesel Platform. Created in 2002, the platform brings together
supplier skills in diesel exhaust aftertreatment. Aaqius & Aaqius,
Inergy, and Rhodia are pooling their managerial, business, and
technology know-how within the platform to adopt existing, off-the-shelf
technology. The
business rationale is to offer an integrated technology solution for
diesel exhaust aftertreatment. Platform partners focus on supporting
vehicle manufacturers, with the first Green Diesel Platform
application— the Audi Q7 diesel with SCR system—due in the U.S. in
2008.
Specialty chemicals group
Rhodia contributes the additive know-how that is behind the Peugeot
solution. Rhodia has refined the Eolys additive formula, which is
now in its third generation and so highly concentrated that 2 L (0.5
gal) are enough to last for 240,000 km (150,000 mi) before the
additive tank needs a refill.
Eolys is dosed to the diesel
tank in a low-ppm (parts per million) concentration every time the
car is refueled. The fuelborne catalyst brings down the temperature
level for DPF regeneration (the burning of soot) by 150 to 200°C
(270 to 360°F), so regeneration can be accomplished in less than 5
min at 450 to 500°C (840 to 930°F), according to Rhodia. The new
additive’s high efficiency also means that regenerating the DPF has
only a low impact on fuel consumption—a less-than-1% increase,
according to Laurent Rocher, Sales & Market Development Manager for
Rhodia. “This compares to around +5% with other technologies,”
Rocher added during a press briefing at the Frankfurt Motor Show.
Inergy, a plastic fuel tank
system supplier, was founded in 2000 as a joint venture between
Plastic Omnium and Solvay. The company brings to the platform the
additive storage and urea system know-how for SCR systems. Urea
storage and distribution is a challenge as SCR technology requires
around 1 L (0.3 gal) of urea solution per 1000 km (620 mi). Inergy
has developed tank solutions that hold 20 to 25 L (5.3 to 6.6 gal)
to give the SCR system an acceptable reach. To accommodate the
necessary installation space, this volume is often packaged in
multiple, separately located tanks. Since the solution freezes at
-12°C (10°F), the Inergy system incorporates a heating element to
ensure that molten urea is available after 20 min at -30°C (-22°F).
Tank, supply module, urea injector, heated lines, and electronic
control are marketed under the name Dinox.
Jörg Christoffel |
