2012 Kia Rio brings 'start-stop' technology to masses

The drumbeat of idling engines at stoplights is starting to be replaced by dead silence.

It's the result of more use of "start-stop" engine technology that shuts off the engine when the car is stopped for more than few seconds, then restarts it, in most systems, when the driver releases the brake.

Commonly used in hybrids, it's just now coming to conventional vehicles in the U.S. market -- mostly high-end vehicles. Though it requires some tricky electronic controls, in a conventional car, a start-stop system requires only a beefed-up battery and starter and a few other parts.

Enter the 2012 Kia Rio subcompact, due in showrooms next month. The most inexpensive car in Kia's lineup -- today, Kia will announce a Rio starting price of $14,350 with shipping -- will offer start-stop as the centerpiece of a $400 "Eco" option on the redesigned 2012.

Kia -- at a price for the masses -- joins BMW and Porsche, which offer start-stop in the U.S. on several new models.

This could be the start of a start-stop wave, says John O'Dell, a senior editor Edmunds.com, who sees it on more than half of all models within five years. ""It's going to be very popular. It's a fairly inexpensive way to get a 3% to 5% fuel-economy increase."

That's a big deal as automakers race to find the cost-effective technology to raise average fuel economy to the required 35.5 miles per gallon by 2016.

Why don't more cars have it? It's partly because of how the Environmental Protection Agency conducts its tests.

With only about six parts, start-stop was a fairly simple addition to save gas in the Rio, says Kia product planner Steve Kosowski. He says Rio owners will gain, even though they won't see it reflected in the window-sticker mileage rating because of the EPA's test procedures.

The non-start-stop Rio will be rated the same as its sibling, the 2012 Hyundai Accent, which doesn't have stop-start. But because the EPA test cycle used few stops long enough for the engine to shut off, Kia estimates that a Rio with start-stop would rate just .1 or .2 mpg higher for city driving, But Kia says it will have much more impact in the real world for owners who choose the option.

Automakers currently are lobbying the government for testing that better counts start-stop in mileage ratings, as is done in Europe.

But some aren't waiting. Here are others leading the way with start-stop:

• BMW. After using start-stop on its M3 performance car, BMW is adding it to its Z4 sDrive 28i sports car and 5-series sedans, among its best-sellers. Stop-start comes with the manual or automatic transmission or both, depending on the model. "We think it could have some gas-mileage gains in normal, everyday driving," said spokesman Dave Buchko. "We're looking at any and all avenues, trying to find any fuel savings that we can."
• Porsche. Now on the Cayenne crossover and Panamera sedan, it's coming to the new 911 sports car. In Porsches, the feature can be turned on or off with a button. Spokesman Nick Twork says start-stop was a key features in boosting the mileage rating of the new 911 by 15% in European testing compared with the outgoing model.