Less drag, MorElectric


Looks like truck technology is migrating toward a territory that railroads have occupied for years – replacing mechanical loads with electrical ones.

Locomotives move by electromotive power. They use mammoth diesels, with cylinders the size of small garbage pails, to spin serious generators, which crank out a generous supply of electricity. The electricity is metered out to electric traction motors that drive the wheels, and off you go.

From both energy and packaging standpoints, it’s a more efficient setup than having the engine drive the wheels mechanically.

Unfortunately, such an arrangement would be cost-prohibitive for powering trucks, at least until a few million copies were sold and economies of scale could drive prices down.

However, the idea is adaptable to driving some mechanical engine loads – the water and oil pumps, and air and A/C compressors, for example. That’s the focus of a collaborative effort by Caterpillar Electronics, Peoria, Ill., in a partnership research initiative with the U.S. Department of Energy (DOE), Kenworth Truck Co., Kirkland, Wash., Engineered Machined Products, Escanaba, Mich., and Emerson Commercial Industrial Motor Group, St. Louis.

Cat Electronics is responsible for system integration, control software development and system performance. Kenworth brings one of its trucks to the party, while Engineered Machined Products makes water pumps, and Emerson brings its electric motor and control expertise.

Cat, which is calling the new venture “MorElectric,” notes that, while the ultimate goal is to reduce parasitic engine power loss, cut emissions and improve fuel economy, there are other advantages as well.

In the MorElectric system, the engine will drive a large generator, most likely mounted inside the bell housing. The generator, which will double as a starting motor, will provide power for electric motors driving accessories that currently are mechanically powered by the engine, via belts or gears.

Such a system, says Cat, would allow flexible vehicle design, because accessories would no longer have to be located in or on the engine. In addition, the system could run its loads only when they were needed, at the speed needed, rather than constantly at engine speed, as in current designs.

Moreover, Cat forecasts a reduction in parts and costs through the use of plug-in modules, which will reduce assembly and repair times.

To further reduce fuel consumption, trucks with MorElectric technology will be equipped to use shore power to reduce idling at truck stops, loading docks or terminals where there’s electricity. An option will be an onboard auxiliary power unit to provide driver comfort until shore-power plug-in locations become more widespread.

Elimination of idling alone could save 838 million gallons of annually squandered fuel, according to the Argonne National Laboratory, Argonne, Ill.

A MorElectric demonstration truck is under development, which the DOE expects will consume 9 to 18 percent less fuel than current-technology vehicles. The only drag is that the new technology won’t be commercially available until 2004.