Precisely Cool Condition:
How Visteon's Taking the Heat out of CAFE
which is making a reputation as a vehicle systems integrator, has gone
under the hood to develop a new engine coolant system that promises to
improve fuel economy and reduce hydrocarbon emissions.
Known as PrecisionCooling, Visteon's technology is a systematic approach
to monitoring and controlling engine temperature by regulating the flow
of fluid and air through the powertrain system.
optimizes the vehicle's use of its radiator, fan, water pump, and heater
core, according to Product Marketing Manager Ed Vela.
"PrecisionCooling is a revolutionary systems level technology at
Visteon. It integrates several of the heating and cooling systems components
as well as certain aspects of the vehicle's HVAC (heating, ventilation,
air conditioning) system," added Davide Piccirilli, Visteon System
the system has been tested on a North American-built, full-size pickup
truck with a V8 engine and a small European sedan. Preliminary results
have been promising, Vela said.
In the tests engines on the demonstration vehicles were able to run at
temperatures 10 to 15 degrees Centigrade above normal and were also able
to warm up faster. This led to fuel economy improvements.
The Visteon Precision Cooling System
"Our development vehicles showed up to a five percent improvement
in fuel economy," Piccirilli said. "That was achieved by operating
the engine at a higher temperature, which results in reduced friction
due to improved oil viscosity. And, we improved fuel economy by throttling
back on the fan when we don't need it."
The PrecisionCooling system also reduced hydrocarbon emissions on the
demonstration vehicles by up to 20 percent, while keeping nitrogen-oxide
(NOx) and carbon monoxide (CO) levels well below EPA requirements, Piccirilli
Again, this was achieved due to a faster warm-up by routing coolant circuits
through the engine as well as operating at a higher temperature.
In terms of passenger comfort, the Visteon system improved the heater's
performance on the demonstration vehicles by 10 degrees Celsius. The air
conditioner worked better too, by three degrees Celsius. "The demonstration
vehicle went from a market follower to a market leader in its segment,"
is that Visteon's customers can decide if they want to increase the performance
of their existing heating, ventilation, air-conditioning (HVAC) system
or, perhaps, downsize components to save weight and cost for the same
output. Visteon is specifically targeting the light truck market in North
America to launch this new technology due to concerns about fuel economy,
Many of the PrecisionCooling components exist today and could be dropped
into an existing vehicle, although OEMs could see weight savings if the
technology was integrated and optimized for a new vehicle, Piccirilli
said. The system could be launched on a 2005 or 2006 model year vehicle.
The system is also designed so it can be integrated into hybrid-electric
vehicles and it will work with an existing 12-volt electrical system or
the upcoming 42-volt system.
Visteon developed PrecisionCooling to address the needs of the Original
Equipment Manufacturers (OEMs), according to Vela. Automakers face increasing
stringent vehicle emissions regulations in North America and Europe. And
in Japan auto makers are concerned about improving fuel standards.
Visteon's forecasters predict that the U.S. Environmental Protection Agency
and the California Air Resources Board will continue to strengthen air
pollution standards. The federal government is also expected to raise
Corporate Average Fuel Economy (CAFE) standards.
The U.S. CAFE standard for passenger cars has not changed since 1990 and
is set at 27.5 miles per gallon. The light truck standard has not changed
since 1996 and it is set at 20.7 miles per gallon.
"Inevitably, the CAFE rules will become more stringent," Vela
said. "And, we have questions over the sustainability of gas prices.
They're currently at $2 per gallon and there is talk that it will approach
$3. Potentially, higher gas prices will drive consumers toward more fuel
In Europe, vehicle emission standards have also been tightened. Euro III,
the current European standard, which went into effect in 2000, covers
both gasoline and diesel engines - unlike the U.S. standard which only
covers gasoline engines. The Euro regulations monitor hydrocarbons, nitrous
oxide, carbon dioxide and particulate matter emissions from diesel engines.
A harsher Euro IV standard is expected in 2005 and an even more stringent
Euro V standard is expected to be in effect by 2008. The move from the
Euro III to Euro IV standard would require hydrocarbon and NOx emissions
to decline by 46 percent, NOx levels to decline 50 percent, CO levels
to dip by 22 percent and particulate matter emissions to be cut in half.
The Euro V standard is still under development.
action, consumers are also demanding less polluting vehicles in both Europe
and North America.
"Consumers are demanding green products. We believe this will be
a stronger trend in the next decade," Vela said.
THE TRADITIONAL COOLING SYSTEM
Current gasoline- or diesel-powered vehicles have a thermostat, a water
pump and a fan. The thermostat is a valve that directs flow to either
the engine's bypass system or to the radiator. Plus, the water pump in
the cooling traditional system is a mechanical device that is linked to
the fan belt and, thus, coupled to the engine's RPM.
"There is a direct correlation between the water pump speed and the
engine's RPM," Piccirilli said. "Higher engine rpm results in
higher water pump RPM, even in conditions where the additional flow is
not necessary." Traditional water pumps also impact engine performance
by leeching horsepower away.
The engine's fan is either electrically controlled, so it can be turned
on or off as needed, or a mechanical fan that is coupled with the engine
RPM. Just like the water pump, the mechanical fan's power is directly
linked to the engine's RPM and can't be altered to adapt to different
Some vehicles, such as those made by Ford Motor Co., also have a degas
bottle, which is designed to remove air from the coolant system. A tube
connects the degas bottle to a nipple on radiator. So, when coolant flows
through the radiator, it automatically flows to degas bottle even when
it's not necessary, Piccirilli said.
THE VISTEON WAY
key difference between Visteon's PrecisionCooling technology and a traditional
coolant system is that the thermostat is replaced with a coolant control
device. This device is a five-port valve, with one input tube and four
output tubes, and controls the coolant flow not only to the radiator and
engine bypass, but also to the heater core and the degas bottle.
"We are now taking control of the coolant's flow. For example, maybe
we want to send the full flow to the radiator instead of the degas bottle
or maybe we want to send more coolant to the engine bypass circuit,"
The one challenge is trying to find space package the coolant control
device in the engine compartment. That isn't much of an obstacle because
the device doesn't need to be located in any one particular spot, according
to the company..
Next, Visteon has integrated the operations of the engine fan, the water
pump and the heater core with the radiator, the engine bypass circuit
and the degas bottle.
With PrecisionCooling, the vehicle's water pump and fan can either be
electrically- or mechanically-powered and independently controlled from
the engine's RPM. The mechanical pump and fan speeds are controlled by
electronic viscous clutch. The clutch will allow both the water pump and
fan speed to be controlled independently of the engine's RPM.
All of these operations are linked together by a control module, which
can be separate unit or the software can be integrated into the vehicle's
existing powertrain control module.
"The combination of all of these devices and how they operate to
optimize the engine operating temperature at a higher set point that allows
us to integrate the other systems, such as the climate control,"
"By having control of the heater core, we can determine when it is
necessary to send energy into that component, thereby affecting the engine
performance and heating performance."
During start up mode, when the vehicle has been parked overnight and the
engine is cold, the coolant is kept in the bypass loop, working only through
the engine so it can warm up to operating temperatures faster. If the
driver needs heat, the PrecisionCooling system will divert some of the
coolant to the heater core.
test vehicles were able to produce heat for the passengers that was 10
to 15 degrees Centigrade greater than the traditional system. Once the
coolant achieves its operating temperature, the system will divert the
fluid to the radiator and degas bottle, as needed so the engine won't
overheat. And, PrecisionCooling will adjust the fan and water pump speeds
In power and acceleration mode, when the vehicle is climbing a hill or
trying to pass someone, the water pump and fan speeds can be adjusted
to maximum to help induce cooling. The PrecisionCooling system will route
coolant to the radiator, degas bottle and heater core as needed.
Unlike traditional cooling systems, which react to changes in engine temperature,
Visteon's PrecisionCooling system is proactive. It will anticipate what
level of heat will be generated and adjust the water pump and fan settings
to promote cooling ahead of time to maintain coolant temperature,"
And in economy or cruise mode, when the vehicle is on the expressway,
for example, the PrecisionCooling system again will control the coolant
flow to the heater core and radiator while controlling the fan and water
pump settings as required.
Want more info on Visteon? Visit the company's climate systems site for
more details. http://www.visteon.com/climate/
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