Nov90610 pages
daily
nnnnTHURSDAY
nnnnNOVEMBER 9, 2006
nnnnPAGE 4 OF 4
nnnnviewpoint
nnnnTWO FUEL-SAVING OPTIONS
nnnnFOR CONVENTIONAL ENGINES
nnnnCostly hybrid powertrains and exotic new fuels aren't the
nnnnonly options OEMs are pursuing to boost vehicle fuel econ-
nnnnomy. Another quicker option is squeezing more efficiency
nnnnfrom conventional engines by better
nnnnmanaging how their power is used.
nnnnGates Corp., best known for its
nnnnengine drive belts, has helped
nnnndeveloped two systems that do just
nnnnthat. One is a belt-driven electro-
nnnnmechanical drive (EMD) that
nnnnenables an engine to shut down at a stoplight and restart
nnnninstantly when the driver taps the throttle. The second is
nnnnDrive, a two-speed belt drive that reduces power losses due
nnnnto engine-driven accessories.
nnnnAlexander Serkh, advanced
nnnnproduct engineering manager at the
nnnnGates Technical Center in Rochester
nnnnHills, Mich., explains.
nnnnA Tom kins Company
nnnnHow did Gates get involved
nnnnwith these two fuel-saving
nnnnoptions?
nnnnBoth systems use special drive
nnnnbelts, and that's one of our centers
nnnnof expertise. We've worked very closely with other compo-
nnnnnent suppliers to develop both systems.
nnnnHow does an engine start-stop system work?
nnnnConventional cars have a starter motor geared directly to
nnnnthe engine's flywheel and a separate belt-driven alternator
nnnnthat provides electrical power to the vehicle once the engine
nnnnis running. Gates electro-
nnnn|—1 i\ , I p \ mechanical drive combines both
nnnnW I I-1 V J functions in one belt-driven unit.
nnnnELECTRO-MECHANICAL DRIVE An electronic controller deter-
nnnnmines when to shut off the
nnnnengine, when to restart it and whether the starter-generator
nnnnis working as an electric motor or power generator.
nnnnWhy does a start-stop system require a
nnnnspecial belt?
nnnnThe load on the belt of a start-stop system is up to three
nnnntimes higher when the engine is being started as when it's
nnnnrunning. And in some start-stop systems, the starter also is
nnnnused to propel the vehicle for several seconds, which puts a
nnnnsustained strain on the belt.
nnnnGates has developed a start-stop belt that lasts 150,000
nnnnmiles and can handle 500,000 startups. Gates EMD tech-
nnnnnology is in production now for two models built and sold in
nnnnEurope by PSA Peugeot Citroen and currently on the 2007
nnnnSaturn Vue Green Line Hybrid SUV in North America.
nnnnWhat about Gates' two-speed belt drive?
nnnnThis solution addresses the inherent problem of wasting
nnnnengine power when driving accessories such as the power
nnnnsteering pump and air conditioning compressor.
nnnnAccessories are powered by a drive belt that loops
nnnnaround a pulley on the end of the engine's driveshaft and
nnnnpulleys on each device. The faster the engine goes the
nnnnfaster all the accessories turn.
nnnnThe problem is that accessories are generally designed
nnnnto function at engine speeds at or slightly above idle. At
nnnnactual driving speeds, the engine wastes power by turning
nnnnaccessory pulleys faster than necessary. We've come up
nnnnwith a system called E^ Drive that can improve drive effi-
nnnnciency, boost fuel economy and benefit the environment.
nnnnHow does E*3 Drive improve Economy,
nnnnEfficiency and the Environment?
nnnnOur system utilizes two belts. One drives the accessories at
nnnntheir optimized speed during cruising to reduce engine
nnnnpower consumption. When the engine slows to idle, the
nnnnsecond accessory drive belt is automatically enabled, which
nnnnincreases the accessory drive
nnnnto a proper speed. The system
nnnnuses standard components
nnnnand only needs to work during
nnnnidle —about 5% of running
nnnntime. Competing devices reduce pulley speed during above-
nnnnidle conditions, so they must operate 95% of the time,
nnnnthereby raising noise and durability issues.
nnnnOur system allows accessories to operate more efficiently
nnnnat closer to idle-speed than today's systems. This reduction in
nnnnspeed allows for greater component reliability and durability
nnnnand enables the engine to produce more torque for vehicle
nnnnacceleration. As a result, the E^ Drive System produces a
nnnnmore optimal accessory drive, while reducing fuel consump-
nnnntion and CO2 emissions by as much as 5% each.
nnnnTo learn more about Gates and its electromechanical drive
nnnnand E3 systems, contact Darren Greene at (248) 260-2313
nnnnor dgreene @ gates.com.
nnnnContents © 2006 Hampton AutoBeat LLC. All rights reserved.
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