Next Wave of Hybrids Getting an Exciting New Makeover
OIT -- Fans of the gasoline engine may feel a slight chill as they walk through the exhibits at the North American International Auto Show.While an ice age for internal combustion engines does not seem imminent, it is clear from the number of hybrid-power vehicles on display here that automakers are reserving their warmest feelings for powertrains that team electric motors with petroleum-burning engines. The best-selling car in the United States, the Toyota Camry, will add a hybrid option for the redesigned 2007 model that goes on sale this spring. Equally significant, the next Lexus flagship, the LS460, will also join the hybrid fleet, providing a philosophical bookend to the frugal Prius at the other end of Toyota's line. With these additions, Toyota expects its global sales of hybrids to top 400,000 in 2006. General Motors showed hybrid versions of its large SUVs that will go on sale next year as 2008 models, and announced a Cadillac Escalade hybrid. Design studies from various automakers suggest that hybrids will be coming in other shapes, too: Ford rolled out a design study for a sporty diesel-hybrid coupe, the Reflex; Mitsubishi showed the CT, a concept car that may hold engineering promise; and Subaru displayed the B5-TPH, a high-performance two-seater. Even longtime hybrid doubters like Robert Lutz, vice chairman of GM, are admitting that the systems have gone mainstream. "They're here, and if we've got to have them, at least we have the most economical one," he said. GM's Saturn division will charge customers a premium of less than $2,000 for the "mild" hybrid system in the Vue Green Line utility wagon. The system delivers power directly to the gasoline engine using a motor-generator that replaces the conventional alternator, rather than driving through the transmission. GM says the hybrid Vue will be the lowest-priced hybrid SUV when it arrives in showrooms this summer. The Vue's 42-volt system, using an approach less complex than the high-voltage equipment of other hybrids, shows an emerging diversity in technology - and customer appeal. While early hybrids emphasized environmental benefits, recent entries like the Honda Accord hybrid have played up the boost in acceleration provided by an electric motor; the Vue appeal is a low purchase price. GM also used the Detroit show to highlight the two-mode hybrid it is developing with BMW and DaimlerChrysler. The system, to be used first in the Chevrolet Tahoe and GMC Yukon, uses electric motors inside the transmission to augment a 300-horsepower V-8. The two drive modes, one for slower city driving and the other for highway cruising, are expected to improve mileage by 25 percent, GM says. The propulsion system in the Mitsubishi CT concept places its electric motors - four in all - out at the wheels, using them both for propulsion and stability control. Motors at the wheels are used in Honda's second-generation FCX fuel-cell research vehicle: 25-kilowatt wheel-hub motors at each rear wheel supplement an 80-kilowatt motor driving the front wheels. While hybrid designs vary greatly in layout and technical details, they all rely on batteries to store power for the electric motors. At the Detroit show, it was apparent that there is little consensus in battery technology. Conventional cars carry a heavy lead-acid battery to start the engine and power accessories, but hybrids depend on high-power battery packs using different chemistry, typically nickel-metal hydride batteries that are scaled-up versions of those used in cellphones and power tools. They need careful computer management to charge and discharge correctly and are sensitive to temperatures. They also take a long time to charge. Subaru engineers who are searching for a better battery - one that is lighter, more powerful and can accept a charge faster - think that lithium ion units, as used in the B5-TPH concept car, are the best option. These batteries, already used in power tools, require about half the space of nickel batteries, weigh about half as much and accept a charge more quickly without damage. Among the different kinds of lithium ion batteries available, manganese units have recently gained support because they are cheaper to make and less prone to overheat. But battery experts say this formulation typically offers a much shorter life before performance begins to degrade. Not only is there a battle over battery technology, there is a shoving match among potential suppliers of hybrid-car batteries. Subaru's parent, Fuji Heavy Industries, working with a battery supplier, NEC Lamilion Energy, claims to have developed a manganese-lithium ion battery that will last more than 10 years and can charge in a little more than five minutes. Other makers have concentrated on nickel batteries. SAFT, a French company, and Johnson Controls, a large automotive supplier, announced a joint venture to produce nickel batteries for hybrids; the battery packs are expected to last more than 15 years. While today's hybrid cars use gasoline engines, there is interest in combining fuel-sipping diesels with electric motors to improve fuel economy. As cleaner diesels emerge, the proposal becomes more attractive. "A diesel hybrid is, we think, one of the engines of the future," said Mark Fields, executive vice president for the Americas at Ford.
|<< PREVIOUS||NEXT >>|
blog comments powered by Disqus