Less than 10 years ago, most cars in the U.S. were still using four- and five-speed automatic transmissions. Now, they’re using six-, seven-, and eight-speed transmissions, and a nine-speed automatic is on its way. When will the madness end?
Soon, says German transmission maker ZF. Julio Caspari, the North American president of the transmission maker says that his company and others started the race to aid in engine efficiency, allowing cars to run at lower engine speeds. But their incremental gains are becoming minute. According to Caspari in an interview with Automotive News, his company’s current eight-speed is only 11 percent more efficient than its six-speed.
Currently, many luxury automakers are using versions of ZF’s eight-speed, including BMW across its range, and Chrysler for the full-size 300 sedan. Chrysler is also planning to use a nine-speed automatic transmission for its upcoming Chrysler 200 and Dodge Avenger midsize sedan replacement.
Automotive News reports that Hyundai is experimenting with a 10-speed automatic transmission for future versions of the Hyundai Genesis and Equus sedans, and probably for the Kia K9, which shares the same basic mechanical parts. After that, however, heading to a 11-, 12-, or any number higher -speed transmission could add cost and complexity without any realized gains in fuel efficiency that automakers are searching for as they prepare for mounting Corporate Average Fuel Economy (CAFE) regulations from the federal government set to go up to 54.5 mpg by 2025.
Eventually, it may all end up coming down to automakers following Nissan’s lead, using continuously variable automatic transmissions across most of its lineup. Instead of using a fixed number of gears, the Nissan transmission uses a chain-link belt that shuffles across two cone-shaped pulleys to give a nearly infinite variability, instead of fixed gears.
So expect the ceasefire to come soon, or at least an armistice. With Hyundai and ZF reportedly still developing transmissions with more gears, though, the race may still go on for at least the next decade. “Soon,” after all, is a relative word.
Source: Automotive News (Subscription required)