Most folks envision some wondrous new technology sweeping in and replacing the old faithful internal combustion engine (ICE) virtually overnight. Ain't gonna happen. Those in the know have long viewed the automotive powertrain evolution as a chart with market penetration up the vertical (totaling 100 percent) and calendar years along the horizontal axis.
Electric and steam were substantial segments in the industry's early years before gasoline ICE, for excellent reasons, grew to 100 percent. Following the fuel crises of the 1970s, a sliver of diesel ICE (long dominant in heavy-duty trucks and buses) began to grow within the passenger vehicle spectrum, then shrank again to barely visible in this country. Given different priorities, taxation and emissions requirements, however, diesel has grown in Europe and elsewhere to nearly 50 percent in some markets today.
You need a microscope to see any battery electric vehicle (BEV) share despite ill-considered laws attempting to force BEV sales in some U.S. states. Hybrid electric (HEV), while beginning to grow, remains barely visible as an emerging segment. And the promised kind of affordable furl cell electrics (FCEVs) seems perpetually 10 years away.
Where do industry experts and leaders see these and other "advanced" powertrain technologies a decade from now? We asked Ford Vice President, Research and Advanced Engineering, Gerhard Schmidt; GM Executive Director, Hybrid Powertrain, Larry Nitz; and Toyota Executive Engineer, Environmental Engineering, Dave Hermance for their thoughts.
Ford Hybrids
"Hybrids are not rocket science," Ford's Schmidt offers. Honda's Insight and Civic and Toyota's Prius HEVs have long been available, and more will arrive this year, including Ford's Escape Hybrid. "We are the first non-Japanese company offering a full hybrid," he says, "and first with an SUV. We are pioneering this technology in this type of vehicle."
Ford has designed and developed its own hybrid system, though it is similar to Toyota's Hybrid Synergy Drive (HSD) and incorporates a version of the Prius' Aisin two-motor transaxle, including its Toyota patents. "This is a no-compromise hybrid," Schmidt contends. "It's a tour cylinder engine in combination with an electric motor with the performance of a V6. We intend to expand the range of products with this technology,."
Is a hybrid's extra cost worth its efficiency benefit, and can it be competitive with modern diesels offering similar efficiency with lower cost and complexity? "Should we have to go to a partial zero emission (PZEV) standard in California," Schmidt responds, "this could be an interesting competition. You have some really expensive parts in the hybrid, especially the battery, but you would also have added cost for the diesel's after-treatment.
"If you drive in downtown Tokyo, a gasoline electric hybrid may be an excellent choice. But if you drive from Detroit to Chicago, a high-torque diesel is a better choice, because you set your cruise control and get no benefit from regen braking or start/stop. In Tokyo, you might see as much as 50 percent economy benefit with a hybrid, but with typical European driving, you won't see the stone benefits. It depends on the customer profile and the driving cycle.
"The main benefits of a hybrid are regenerative braking and start-stop operation. You also get some benefit from downsizing the engine and making it a little more efficient, but you lose towing capacity. And if you go uphill for half an hour, you won't have energy in the battery.
GM Hybrids
"We have a portfolio of systems to deploy where we think they make sense," says GM's Nitz. Two different GM systems are now in limited production. The first, in Chevy Silverado and GMC Sierra hybrids, the first full-size pickup HEVs, are available to fleets this year and retail customers for '05. "This is a flywheel/alternator/starter technology," Nitz says. "We've basically downsized the torque converter and wrapped a motor/generator around it, which keeps the transmission's length and diameter the same. It does decel fuel cut-off, engine stop/start and a mild amount of regenerative braking, and it gets about a 10 percent increase in fuel economy."
Because the 42V electric motor provides performance-boosting torque, regen braking and a ll0V power takeoff, but not power to the wheels, this system is considered a "mild" hybrid. "Some people criticize that," Nitz says, "but it delivers the same hybrid capability that a strong hybrid does." Given the $2,500 premium, volumes will be modest--500 for fleets this year and "several thousand" in '05. "The market will tell us how many it wants," he adds.
The second, Advanced Hybrid System II for urban buses, a joint development with GM Allison Transmission, is a "two-mode input compound split architecture," Nitz explains. "The power flow is split ... part mechanically, part electrically. For a vehicle of that size with that amount of tractive effort and both city and highway speeds, we went with a compound split--two electric CVTs that select between each other. The starting mode is an input split; then, at a synchronous point around 20 mph, a fixed gear ratio of about 1.7, it shifts to a compound split. It gives you excellent balance of mechanical vs. electric power at the start and in the city and excellent balance of electric vs. mechanical power at higher speeds.
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