The technology is called stop-start, idle-stop or micro-hybrid. Bottom line: It’s a cost-effective way to get a 10 percent efficiency improvement.
In recent years, Europe has been embracing stop-start systems—also known as “micro-hybrids”—but the US has been slow to adopt the technology. Until now. Automotive News reported this week that Hyundai and Ford will begin offering stop-start systems on several of their models.
“Start-stop will be a key part of our development activity in the next two product cycles,” Timothy White, Hyundai-Kia’s senior powertrain manager, said last week at the SAE World Congress. That could mean stop-start technology on a wide range of North American Hyundai and Kia models in about two years.
Ford promises to offer micro-hybrid technology on about 20 percent of its global nameplates by 2014. And Automotive News reported last year that Mazda is planning to bring its i-stop system to US cars.
What’s In a Name?
The auto industry has not settled on how to name or market the fuel-saving technology, which improves fuel economy by about 5 – 10 percent. Some will passionately argue that it’s not really a hybrid of any kind—but if you grant that the technology generates and re-uses energy for greater efficiency, then it belongs in the family hybrid technologies, which ranges from micro-hybrid to plug-in series hybrid (also known as extended range electric vehicle).
Whatever you call it, the technology is designed to shut off the engine when the car slows down or comes to a stop. The system is commonly composed of an energy storage device—like a battery—and a beefed-up starter-motor that can also act as a generator. As soon as the driver puts in the clutch, moves the shift lever, or accelerates, the battery powers the starter motor, which quickly switches on the engine. Full hybrids also employ a start-stop strategy.
Europe has so many cars with stop-start systems that it’s hard to keep up. The list includes the BMW 1-Series, BMW 320d, Volkswagen Passat BlueMotion diesel, Toyota Auris (sold as a Corolla hatchback elsewhere), Mini Cooper, Citroen C2, and Smart ForTwo.
Considering the relative lower cost of a stop-start system, global adoption of the technology is expected to outpace full hybrid or pure electric cars. Strategy Analytics Automotive Electronics Service forecasts that global sales of stop-start micro-hybrid systems will reach nearly 20 million units a year by 2015. Auto supplier Bosch has sold more than a half-million stop-start systems to BMW, which offers the system as standard equipment in its 1-series vehicles. Supplier Valeo is expected to supply 1 million systems to PSA Peugeot-Citroën by 2011.
The move to stop-start technology by Hyundai and Ford will likely be followed by other global automakers, which are scrambling to find the most cost-effective strategies to meet tougher efficiency and emissions standards.