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Going Further on the Same Tank

A technology coming to Chrysler vehicles can improve the fuel economy of standard gasoline engines by 25 percent.
August 19, 2010

Chrysler is unveiling a way to squeeze more fuel efficiency out of existing gasoline engines, adopting a technology pioneered by Fiat, which controls Chrysler. The effort represents the latest strategy by automakers to meet federal standards that require an automotive fleet to get an average of 35.5 miles per gallon by 2016.

MultiAir at work: This photo shows the position of red solenoids that push oil into actuators to open and close air-intake valves.

While General Motors and Ford have made progress in retooling their gasoline engines to make them more fuel-efficient, Chrysler has lagged. Now Chrysler hopes to catch up with the MultiAir technology, which it claims will increase fuel economy by 25 percent.

In a conventional engine, a camshaft opens and closes the valves that bring air into the engine. These valves all make the same movement all the time, even at low engine speeds, when less air is required. The MultiAir system is different because it electronically determines the most efficient way to open and close the valves, depending on road conditions and necessary power, allowing the car to run more efficiently at all speeds.

Here’s how it works: A small solenoid, a mechanical device that can act like a switch, opens and closes the valves. This solenoid adjusts the cycle of valves opening and closing so that the engine takes in the best amount of air for the load it’s handling at any given moment. Opening the valves for a short period of time at low loads is less work for the engine, increasing its efficiency. And because the system can open the valves longer when more power is needed, it can extract more energy out of the engine.

As a result, MultiAir not only increases fuel economy, it also increases the engine’s torque by 15 percent, says Chrysler spokesman Nick Cappa.

“It gives the engine a more efficient breathing pattern whether at idle or 6,000 rpm,” Cappa says.

The MultiAir technology was launched by Fiat in Europe in 2009. Its first application in the U.S. will be on the 2011 Fiat 500. Cappa says Chrysler is looking to use MultiAir on its new, more efficient Pentastar six-cylinder engines, which are used in everything from pickup trucks to small sedans. Cappa says the cost of adding the technology to a car hasn’t been determined yet.

Chrysler’s use of the technology is the latest attempt to improve the fuel efficiency of internal combustion engines. Shifting to radically different engines, like those in electric cars, may offer the best long-term benefits for the environment and fuel economy. But the infrastructure necessary for vehicle charging stations won’t spring up overnight.

The best near-term solution still comes from making the internal combustion engine burn cleaner and more efficiently, says Charles Territo, a spokesman for the Alliance of Automobile Manufacturers. “All manufacturers are working on new ways to get more miles out of a gallon of gasoline from an internal combustion engine,” he says.

For instance, Ford has its EcoBoost system, which uses a turbocharger and direct fuel injection to cut the engine size in half, reducing its weight and improving fuel efficiency by roughly 20 percent. General Motors is employing a variety of strategies, including direct injection, which helped the 2010 Chevrolet Equinox SUV get rated at 32 miles per gallon.

Neither GM nor Ford would comment on Chrysler’s MultiAir, but analysts praise the design. “I think MultiAir is a breakthrough technology,” says Michael Omotoso, senior manager of global powertrain for J.D. Power and Associates. He says the design will help Chrysler not only keep up with Ford and GM but possibly pull ahead on fuel economy while maintaining profitability.

Another analyst, John McElroy, predicts that Chrysler will have MultiAir on every one of its gas engines within five years. McElroy, host of the webcast Autoline Daily, has tracked the auto industry for over 30 years. He says the technology could be far cheaper than hybrids, which involve two separate power systems and an expensive battery pack, and diesels, which require emission control systems that average between $3,000 and $4,000 for a six- or eight-cylinder diesel engine. By not needing any additional costly moving parts, MultiAir could also be cheaper than Ford’s EcoBoost, which uses expensive turbochargers, McElroy says. On the 2011 Ford Explorer, EcoBoost is offered as a $995 option.

John German, program director of the International Council on Clean Transportation, is skeptical of Chrysler’s claims that MultiAir can improve fuel economy by 25 percent. He estimates that it’s closer to 10 percent to 15 percent, which would be less than what hybrids achieve. Even so, he thinks MultiAir is a “clever” system and applauds Fiat for answering the long-daunting question of how to control valves electronically.

Though Chrysler’s Cappa is optimistic about MultiAir, he acknowledges that it won’t be enough on its own for the company to meet the new fuel economy standards. “Transmissions, vehicle weight, and a number of other factors will all play significant roles in achieving the new standards,” he says.

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