BASF's hydrocarbon trapping technology, which
prevents a large amount of evaporative emissions from reaching the
environment, can help automakers with tough, new standards. Under a
phase-in schedule beginning now, carmakers are required to
dramatically reduce evaporative emissions. All gasoline-powered
vehicles will be required to meet the new standards by 2007.
This technology provides carmakers with an additional tool to deal
with increasingly stringent California LEV (Low Emission Vehicle)
II standards and United States Environmental Protection Agency
(EPA) Tier II standards for evaporative emissions that began to
take effect in 2004. All gasoline-powered vehicles will be required
to meet the new standards by 2007.
Evaporative emissions are hydrocarbon (HC) vapors that come from
sources in an automobile other than the exhaust system. Major
sources of evaporative emissions include an automobile's air intake
system, fuel rail, exhaust gas recirculation system and gas
tank.
With today's efficient exhaust emission controls and cleaner
gasoline formulations, the United States Environmental Protection
Agency estimates that evaporative emissions can account for the
majority of the total hydrocarbon pollution from current model cars
on hot days when ozone (smog) levels are highest.
BASF developed a proprietary zeolite composition based on its
earlier successes in reducing "cold- start" emissions (pollution
that escapes a car in the first minute or so after ignition). This
new zeolite composition has a high capacity for hydrocarbons, which
are trapped within its pores and channels. BASF coats the zeolite
composition onto a substrate using a special binder that is
designed to provide excellent adhesion.
This "hydrocarbon trap" is placed between a car’s air cleaner and
engine where it can capture hydrocarbons that are escaping through
the air intake. This position is desirable because the air intake
system contributes as much as 50% of total evaporative
emissions.
The trap adsorbs hydrocarbons that are emitted when the engine is
stopped. Once the car is started and driven, the trap releases the
hydrocarbons into the engine where they are burned. In this way,
the new hydrocarbon trap continually regenerates itself.
The hydrocarbon trap is designed to be tamper proof so it does not
require the use of costly on board diagnostics (OBD) equipment. The
trap also has minimal impact on airflow into the engine and can
withstand exposure to ice, water, salt, dust, air filter surfactant
and engine backfire.
Our hydrocarbon adsorbent coating can be applied to substrates of
various size and shape to address individual emission control
needs. The choice of substrate is not the only source of control,
but also the coating amount. This way the hydrocarbon adsorbing
capacity of the trap can be tailored to the vehicle application.
The first commercialized product is a metallic monolith design. The
monolith is placed in the air intake tube between the engine and
the air cleaner. Another approach involves coating a screen that
can be placed directly into the air cleaner itself as shown in the
photo above.
The BASF hydrocarbon trap's ability to prevent evaporative emission
from the air intake has been demonstrated by SHED (Sealed Housing
for Evaporative Determination) testing. A modified version of the
standard SHED test was used to evaluate the HC trap's effectiveness
on air intake emissions. The difference was that a bag was placed
over the air intake in order to isolate the air intake emissions.
The bag was later analyzed for collected hydrocarbons. Two-day
Dirurnal SHED tests show that the HC trap significantly reduces air
intake system evaporative emissions.