CLEVELAND — Despite a two-year setback due to a slow economy, engineers say they are more certain than ever that automakers will soon replace the venerable 12-volt car battery with a 42-V model. Automotive experts at the 42-Volt Automotive Systems Conference here this past week predicted that half of all new vehicles will incorporate 42-V electrical architectures by 2010, and 100 percent will have the technology by 2020.

The massive technological changeover will create new opportunities for manufacturers of batteries and power electronics, and will usher in a new era of high-tech automotive features that today's 12-V batteries couldn't support, engineers said.

Several car manufacturers also said they already have, or will soon introduce, cars with 42-V architectures. Toyota described the development of its new Crown Mild Hybrid, which incorporates a 42-V/14-V electrical architecture, and Ford Motor Co. said it is working on a dual-voltage (42/14-V) station wagon, the Mondeo. DaimlerChrysler, meanwhile, has announced that it will also employ a dual-voltage design on a future Mercedes SL.

"We know that 42 volts is definitely going to happen; it's just a matter of when," said Randy Frank, automotive-sector technical-marketing manager for International Rectifier (El Segundo, Calif.) and co-chairman of this week's 42-volt conference. "The programs may be pushed out due to current economics, but as the power loads in vehicles continue to grow, it's becoming more obvious that 42 V is the most viable solution."

Engineers cited a multitude of reasons for the imminent change, starting with fuel economy and reduced emissions. A 42-V architecture, they said, is seen as an enabler for such features as "idle stop," in which a vehicle's engine would shut down at traffic lights, saving gas and reducing pollutants.

"The regulatory push is the key," said Philip Gott, director of consulting for the Global Automotive Group at DRI-WEFA Inc. (Lexington, Mass.), a consultant. "Forty-two volts can give you fuel economy benefits that would otherwise be available only from the introduction of advanced power train technologies that would require huge capital investments."

In a presentation to an audience of about 200 automotive engineers, Gott described 42-V architectures as a "cost-avoidance strategy" that could help automakers meet stringent fuel economy and emission requirements without developing a new breed of power train technologies. "We expect 42 V will become an integral part of every manufacturer's strategy," he said.

Newfound optimism

The optimistic assessments of 42-V technology were 180° from those voiced just two years ago at a Future Car Conference in Costa Mesa, Calif. There, engineers and technical panelists questioned whether 42-V technologies were really needed. "If it's costing us more, then we have to ask ourselves why we're doing this," said one engineer in a typical lament.

But participants at this week's conference did not ponder why the switch will be made, only when and how. Engineers said that in the past two years automakers have pushed back the 42-V timetable by investing more in the engineering of existing 12-V systems. But they added that auto companies need to maintain their investments in 42-V development in order to meet the needs that will arise when the current recession ends.

"We've seen a couple of years' delay in the automotive-model changes because of the economy," said Norman Traub, director of the 42-V initiative for the Society of Automotive Engineers' Strategic Alliance (Troy, Mich.). "But when the economy turns, the model changes will start again and the power requirements will go up, and the conversion to 42 V will become necessary."

Beyond fuel economy and emission reduction, 42-V architectures are seen as a necessity for a raft of bells and whistles that automakers want to add. Such features as variable valve timing, electric power steering and braking, dynamic suspensions, and heated steering wheels and windshields would be impossibilities with today's 12-V architectures. Not only do such features offer comfort and convenience for consumers, but some of them form the foundation for future automotive capabilities, such as adaptive cruise control and collision avoidance.

The 42-V systems could serve as the electrical backbone for the larger electrical loads such technologies pose, observers said. Moreover, 42-V architectures allow engineers to deal with these larger loads without a corresponding increase in the thickness of wiring harnesses. Wiring thickness is a function of current, rather than voltage, engineers said.

Industry analysts maintained that the move to the larger electrical loads is inevitable, and warned that automakers must be prepared to deal with it when the time comes. "The longer we postpone this change, the steeper the uptake curve will be and the more difficult the financial end of it will be," DRI-WEFA's Gott said.

Increasing the investment in 12-V technology is just "a stopgap measure," added Traub of the Society of Automotive Engineers. "In time, we're going to have to make this switch."

Several industry analysts predicted that all new vehicles will have 42-V systems by 2020. Some vehicles, they said, will still use hybrid 42/14-V systems, which employ both a 12-V battery and a 42-V battery, while others will use a single 42-V battery. Analysts also said they expect a quarter to half of all new vehicles to use hybrid 42-V systems by 2010.

Long road

But engineers warned that the change to 42 V will travel a lengthy road filled with scores of technological hurdles. Engineers compared the task to the one automakers faced a half-century ago, when they switched from the 6-V to the 12-V battery. Traub said that General Motors started the switch in 1955 and Volkswagen was the last to come on board in 1966. "It took 11 or 12 years to make the change back then," Traub recalled. "It could take even longer this time."

First on the agenda for automakers, said Traub and others, are such issues as battery technology, arcing, corrosion and the higher cost of power semiconductors for 42-V systems. Batteries are a particular problem, he said, because 42-V versions do not have the same long-life characteristics as their 12-V counterparts. A number of suppliers offered solutions at the conference, including lithium-based models, along with nickel-metal hydride and sealed lead-acid.

Analysts predicted that lead-acid would be the favored battery technology in the early years of 42-V systems, mainly because of its lower cost.

"A lot of the technical problems come back to cost," Traub said. "You can get better batteries at a cost. You can solve arcing and corrosion by putting in battery disconnect switches and sealed connections at a cost. It's not that we don't know how to do it. It's just that it becomes expensive when you roll all the new technology together into a new vehicle."

Opportunities abound

Analysts said that the move to 42 V could open the market for some automotive suppliers. "There are a lot of opportunities there for power supply manufacturers," said Linnea Brush, senior research analyst for the Darnell Group (Corona, Calif.).

Opportunities in 42-V are said to be particularly good for makers of batteries, voltage regulators, motor controllers, power semiconductors, dc/dc converters and other types of load control devices.

Engineers said it's important for the entire auto industry to lock on to 42 V as the high-voltage solution. If the industry doesn't, it will run the risk of some engineering groups' opting for a different solution.

"If 42 V isn't a done deal, then someone will start looking at higher voltages, especially for traction applications," said Frank of International Rectifier.

Traub said the industry must continue its work on 42-V standards, as well. Working groups are putting together a standard (ISO 21848) that describes a 42-V system, including such parameters as maximum steady-state and reverse voltages. "The goal is to have the formal ISO standard completed by the end of next year," he said.

Engineers at the conference called agreement on such matters critical, allowing suppliers to build new devices to a single specification. "If we don't have a standard, then suppliers won't know which way to go with the technology," Traub said. "But as long as there's a standard, suppliers will be more inclined to develop products for it, and we can start moving forward."