Nov90610 pages

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daily

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THURSDAY

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NOVEMBER 9, 2006

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PAGE 4 OF 4

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viewpoint

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TWO FUEL-SAVING OPTIONS

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FOR CONVENTIONAL ENGINES

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Costly hybrid powertrains and exotic new fuels aren't the

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only options OEMs are pursuing to boost vehicle fuel econ-

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omy. Another quicker option is squeezing more efficiency

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from conventional engines by better

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managing how their power is used.

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Gates Corp., best known for its

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engine drive belts, has helped

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developed two systems that do just

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that. One is a belt-driven electro-

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mechanical drive (EMD) that

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enables an engine to shut down at a stoplight and restart

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instantly when the driver taps the throttle. The second is

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Drive, a two-speed belt drive that reduces power losses due

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to engine-driven accessories.

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Alexander Serkh, advanced

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product engineering manager at the

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Gates Technical Center in Rochester

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Hills, Mich., explains.

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A Tom kins Company

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How did Gates get involved

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with these two fuel-saving

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options?

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Both systems use special drive

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belts, and that's one of our centers

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of expertise. We've worked very closely with other compo-

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nent suppliers to develop both systems.

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How does an engine start-stop system work?

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Conventional cars have a starter motor geared directly to

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the engine's flywheel and a separate belt-driven alternator

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that provides electrical power to the vehicle once the engine

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is running. Gates electro-

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|—1 i\ , I p \ mechanical drive combines both

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W I I-1 V J functions in one belt-driven unit.

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ELECTRO-MECHANICAL DRIVE An electronic controller deter-

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mines when to shut off the

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engine, when to restart it and whether the starter-generator

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is working as an electric motor or power generator.

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Why does a start-stop system require a

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special belt?

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The load on the belt of a start-stop system is up to three

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times higher when the engine is being started as when it's

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running. And in some start-stop systems, the starter also is

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used to propel the vehicle for several seconds, which puts a

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sustained strain on the belt.

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Gates has developed a start-stop belt that lasts 150,000

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miles and can handle 500,000 startups. Gates EMD tech-

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nology is in production now for two models built and sold in

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Europe by PSA Peugeot Citroen and currently on the 2007

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Saturn Vue Green Line Hybrid SUV in North America.

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What about Gates' two-speed belt drive?

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This solution addresses the inherent problem of wasting

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engine power when driving accessories such as the power

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steering pump and air conditioning compressor.

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Accessories are powered by a drive belt that loops

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around a pulley on the end of the engine's driveshaft and

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pulleys on each device. The faster the engine goes the

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faster all the accessories turn.

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The problem is that accessories are generally designed

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to function at engine speeds at or slightly above idle. At

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actual driving speeds, the engine wastes power by turning

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accessory pulleys faster than necessary. We've come up

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with a system called E^ Drive that can improve drive effi-

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ciency, boost fuel economy and benefit the environment.

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How does E*3 Drive improve Economy,

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Efficiency and the Environment?

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Our system utilizes two belts. One drives the accessories at

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their optimized speed during cruising to reduce engine

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power consumption. When the engine slows to idle, the

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second accessory drive belt is automatically enabled, which

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increases the accessory drive

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to a proper speed. The system

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uses standard components

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and only needs to work during

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idle —about 5% of running

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time. Competing devices reduce pulley speed during above-

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idle conditions, so they must operate 95% of the time,

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thereby raising noise and durability issues.

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Our system allows accessories to operate more efficiently

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at closer to idle-speed than today's systems. This reduction in

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speed allows for greater component reliability and durability

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and enables the engine to produce more torque for vehicle

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acceleration. As a result, the E^ Drive System produces a

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more optimal accessory drive, while reducing fuel consump-

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tion and CO2 emissions by as much as 5% each.

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To learn more about Gates and its electromechanical drive

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and E3 systems, contact Darren Greene at (248) 260-2313

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or dgreene @ gates.com.

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Contents © 2006 Hampton AutoBeat LLC. All rights reserved.

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