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ARGUABLY
the most cost-effective alternative fuel nowadays is
liquefied petroleum gas (LPG). There’s no need to
convert sugar or corn into ethanol and no need for
complex electrical or hydrogen-powered reciprocating
engines. Also, LPG is actually quite safe in comparison
with other fuels, since it has a high ignition
temperature (about 450°C to 510°C) compared with about
257°C for gasoline, making it less likely to ignite
spontaneously.
Because
it “piggybacks” itself to a conventional gasoline
engine, an LPG-powered vehicle has an emulator to
transfer signals correctly from the ECU (electronic
control unit, a vehicle’s brain) and a
regulator/vaporizer to use heat from the car’s cooling
fluids to vaporize the propane into gas form, as well as
cutting the flow of gas if the engine stops or stalls.
Unfortunately, most LPG-equipped vehicles are of the
open-loop type, in which a restrictor valve is added to
the pipe between the mixer and the vaporizer, which the
installer will use to tune the system. By adjusting this
valve, the installer can tune how much of the vacuum the
vaporizer experiences, so it can control how much gas
can join the airflow and keep the engine in tune.
However, vaporizer diaphragms bed in over time, thus
tuning deviates (and becomes frequent), with significant
drops in power and economy.
Enter
the closed-loop LPG system. This type of automobile LPG
technology uses an electronic controller that operates
in as much the same way as in petrol fuel-injection
systems, using an oxygen sensor to effectively measure
the air-fuel mixture by measuring the oxygen content of
the exhaust and control valve on the converter or in the
vapor line to adjust the mixture. The result is very
little drop-off in power and fuel efficiency.
Recently
a select number of motoring media were given the chance
to experience closed-loop LPG technology with Eroom, a
Korean-based company that has the technology to convert
gasoline-powered automobiles into biofuel rolling energy
savers. Established in 2000, the company has been at the
forefront of alternative fuel, recyclable energy and
air-quality improvement technology research. In fact,
the company claims to have retrofitted 51,200 vehicles
in Korea with Auto LPG technology. “This was borne out
of an obligation to overcome the worldwide pollution
issue, which is becoming worse with each passing day. We
feel that we have a commitment to improve mankind’s
future by contributing to the creation of a global
village where people can live in a clean environment,”
said David Do, Eroom Philippines Inc. (Philippine
representative of Eroom Co. Ltd. of Korea) president.
Scribes
were made to test—from Mandaluyong to Tagaytay and
back—several vehicles equipped with Eroom closed-loop
Auto LPG. Among them were a third-generation (1999 to
2003) Nissan Cefiro 2.0L V6, an eighth-generation (1998
to 2002) Toyota Corolla 1.6L, a 1999 Honda City 1.5L M/T
and a 2001 Honda Civic 1.6L A/T. This writer had the ’01
Civic as his stablemate for the rest of the day, and the
performance was good as advertised. The EP (chassis code
for the ’01 Civic) displayed little drop-off in power
and torque (particularly on acceleration from rest), but
tended to hesitate when letting off the gas and jumping
on the right pedal again. It also tended to take its
sweet time bordering on 1,900 to 2,000 rpm when
traveling on steep 35-degree inclines. Then again, most
LPG-retrofitted vehicles rarely traverse mountain passes
and inclines.
Eroom’s
arrival gives consumers extra—and perhaps better—room
for LPG options to be fitted to their respective
automobiles. |
