With the uncertainty of fuel prices and the concern that gasoline could
again top $4 a gallon across the nation, Americans have been shifting
their vehicle-buying behaviors toward more fuel-efficient vehicles.
While gasoline-electric hybrid vehicles have been getting much of the
attention as the next step in fuel-sipping vehicles, turbocharging
which is used by roughly half of new vehicles in Europe is emerging
as an engine technology U.S. consumers “didn’t know they wanted.”
In a recent study of U.S. consumers by Honeywell, more than half of
those who plan to purchase a vehicle in the next two years believe fuel
efficiency is more important than it was during their last vehicle
purchase. The study also found that more than 80 percent of American
consumers were more likely to consider purchasing a turbocharged
vehicle after learning that the readily available turbocharger helps to
increase the fuel efficiency of a gas engine by up to 20 percent,
without sacrificing performance or reliability.
According to David Paja, vice president, marketing for Honeywell Turbo
Technologies, the recent “Cash for Clunkers” program also was a good
indicator for automakers to incorporate turbo technology into today’s
vehicles. According to the U.S. Department of Transportation, nine out
of the 10 most popular vehicles purchased in the program were equipped
with smaller, more fuel-efficient versions of conventional technology
“For that reason, almost every major automaker has announced plans to
broadly introduce turbocharged engines to the U.S. market in the coming
years. We anticipate demand for gas and diesel turbocharged engines in
the U.S. market may increase from 5 percent today to 25 percent by
2014, and could top 85 percent by 2020,” Paja said.
While turbocharging an engine is nothing new (Volvo, Saab, Audi,
Porsche, Volkswagen, Subaru and even Chrysler have produced
turbocharged cars for years), today’s turbo technology has seen much
improvement over previous generations.
Automotive technicians who have serviced these vehicles know that
turbochargers can be damaged by dirty or ineffective oil. In fact, most
manufacturers recommend more frequent oil changes for turbocharged
engines. This is an issue, as more and more drivers seem to be inching
up in miles driven between oil changes.
One way to combat that problem is selling their customers synthetic
oils, which tend to flow more readily when cold and do not break down
as quickly as conventional oils.
And, because the turbocharger will heat when running, some OEs
recommend letting the engine idle for one to three minutes before
shutting off the engine if the turbocharger was used shortly before
stopping. In fact, most manufacturers determined a 10-second period of
idling before switching off to ensure the turbocharger is running at
its idle speed would prevent damage to the bearings when the oil supply
is cut off.
While some in the industry saw problems, another OE saw potential.
Recently, Ford Motor Co. began introducing a twin-turbocharged, 365-hp
3.5L V6 EcoBoost engine into its vehicle lineup. Ford says these twin
turbochargers harness exhaust gas to pump V8 power out of the
smaller-displacement EcoBoost V6 engine. This technology in
conjunction with direct fuel injection allows EcoBoost to punch above
its size in terms of power and responsiveness.
According to Ford engineers, the EcoBoost engine has been designed with
such refinement that the driver never notices the turbocharger
operation. Sophisticated electronic controls balance boost and torque
levels to give the driver the feeling of continuous torque delivery,
without turbo “whines” and “whooshes” that characterized some
previous-generation turbo engines.
And even though the EcoBoost turbo system runs at a very high
temperature (1,740° F), an air-to-air intercooler is used to cool the
compressed intake air before it enters the combustion chamber, and
water cooling protects the internal turbo bearings in the
high-temperature operating environment.
Ford’s advanced engine engineers explained that the use of these
water-cooled turbochargers combats oil coking. “During normal turbo
operation, the turbo receives most of its bearing cooling through oil,”
said Keith Plagens, turbo system engineer.
“After shutdown, the problems with turbos in the past were you would
get coking in the center bearing oil would collect in the bearings,
the heat soaks in and the oil would start to coke on the side and foul
the bearing. Water cooling eliminates that worry because the EcoBoost
engine uses passive thermal siphoning for water cooling," Plagens said.
Plagens explained that during normal engine operation, the engine’s
water pump cycles coolant through the center bearing. After engine
shutdown renders the water pump inactive, the coolant flow reverses
coolant heats up and flows away from the turbocharger water jacket,
pulling fresh, cool coolant in behind.
Ford believes this combination of direct fuel injection (similar to
what is used in diesel applications) coupled with turbocharging, is the
wave of the future for powerful, fuel-efficient vehicles. By 2013, more
than 90 percent of Ford’s North American lineup will be available with
The engineers at Ford may be on to something. The EcoBoost engine was
honored last month with a Popular Mechanics Breakthrough Award at a
ceremony at the Hearst Tower in New York City. The Popular Mechanics
Breakthrough Awards, now in their fifth year, recognize products and
celebrate innovations poised to change the world. Ford was the only
automaker this year to receive a Breakthrough Award.
*This article was originally published in Underhood Service magazine.