News Column

Stop-Start Can Save Gas, If Drivers Can Accept It

April 17, 2013
save gas, start-stop engine

Stop-start technology can improve the fuel economy of a car or truck by 15%, but the jury is out whether consumers are comfortable enough with their engines shutting down and starting automatically.

The systems save fuel consumption because they turn the engine off when a driver comes to a stop and restart it when a driver presses the accelerator.

In Europe, about 50% of the new cars offered by automakers come with the technology, either as a standard or an option. In the U.S. only a handful of models offer the system, which can cost several hundred dollars.

"We all can put good systems into production," said Scott Dahl, regional president of Robert Bosch's motor division. "But what we need to do is make sure the consumer is informed. We need to let them know what is happening in the vehicle."

Dahl and others who spoke Tuesday at SAE World Congress said U.S. consumers are still apprehensive about allowing their engine to be turned off at a stop light.

There are other possible problems. On a hot day, drivers don't want their air conditioning to be turned off.

Some consumers don't like the engine noise that comes with restarting the car.

But Robert Martin, director supplier Denso's engine group, argues that the industry sometimes worries too much about how sensitive consumers are.

With a good start-stop system, many consumers don't even notice that the engine is on and off.

Martin said the benefits are greater than any initial discomfort.

"If a car is idling, it is wasting fuel," Martin said. "Most people probably don't have a good handle on how much idling they actually do."

Michel Forissier, development director for Valeo powertrain systems, said start-stop systems typically cost between $400 and $500 dollars.

Forissier estimates that drivers can recoup that investment in one to three years, depending on the kind of driving they do. People who drive in congested cities get a greater benefit than those in rural areas.

Europeans were slow to embrace the technology, Forissier said. Manufacturers pushed ahead because it helped them meet stricter fuel efficiency standards.

Now, the U.S. automotive industry is racing to new standards that will be nearly as strict by 2025.

Mark Rakoski, executive director of Mitsubishi Electric Automotive America, said he expects 8 million cars and trucks in the U.S. will be sold with a start-stop system by 2020.

Chrysler, in its annual report in 2012, said it plans to deploy start-stop technology across 90% of its fleet by 2017. It currently offers a Fiat-developed system as an option on its Ram 1500 pickup.

"We are waiting to see how the market reacts," said Francois Fodale, director of powertrain integration for Fiat and Chrysler. "If the market wants it, we will give it to them. Everybody is projecting significant growth, but the consumer has to be willing to pay for it."


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