Why do automatic transmissions now get better fuel efficiency than manuals?
Not so long ago, it was common for automatic transmissions to be referred to as slushboxes, since that's how they often behaved. Rather than use a mechanical clutch, traditional automatic transmissions use a fluid coupling between the engine and the gear-sets to transmit drive torque. This provides some benefits, but isn't a perfect system.
Affordability as the watchword Tuesday as automotive engineers at the SAE World Congress discussed how to meet the new 2016 corporate average fuel economy standards. Automakers will have to get their fleets to an average of 34.1 miles per gallon (35.5 equivalent with other factors for the EPA CO2 limits). Most automakers are already well on their way to this level with their next-generation designs. However, to do it they will have to make improvements to virtually every model in the entire flee
Audi has just added a new transmission option to European-market versions of the A4 and A5. The company's 7-speed S-Tronic dual clutch gearbox is now available with the 2.0L TFSI four cylinder. The A5 picks up 0.3 seconds in the 0-60 run and cuts 1g/km of CO2 emissions with the new gearbox. In the sedan, the mileage is unchanged at 31.8 mpg compared to the 6-speed manual. Here in the U.S., the A4 2.0L currently comes standard with a CVT while manual and conventional automatics are optional.
Over in the UK, drivers buying a new Passat CC now have a new transmission option that gives them an extra 1.2 mpg. The 160 hp 1.8L TSI four cylinder can now be paired with VW's 7-speed DSG dual clutch gearbox in place of the 6-speed manual. The DSG yields a combined 32.2 mpg (U.S.) compared to the 31.0 mpg (U.S.) with the manual. Similarly, the CO2 emissions have dropped from 178 g/km to 172 g/km. The 2.0L TDI diesel and gasoline 3.6L V6 are available with the 6-speed DSG, in addition to the ma
Now that Chrysler's deal to build dual clutch transmissions in a joint venture with Getrag is officially kaput, the company will stick with its existing 6-speed automatic for now. In early 2007, Chrysler announced the deal with Getrag to supply up to 700,000 transmissions a year that could cut fuel consumption by six percent. It was part of a series of powertrain announcements that included the new Phoenix V6 engine family. Getrag was unable to raise the $300 million needed to pay for its toolin
The current credit crisis could be playing further havoc with Chrysler's future powertrain product plans. In the first half of 2007, Chrysler announced investment plans to build two new engine plants and a transmission plant for 2010 model cars. The transmission facility was to be a joint venture with Getrag to build fuel saving dual clutch transmissions. Chrysler already offers German-built Getrag DCTs in the European specification Journey and Sebring. Unfortunately Getrag's apparent inability
There's no doubt that there are a lot of advances in powertrain technology that will improve the efficiency of vehicles over the next few years. There are near-term features like direct fuel injection, turbocharging and dual clutch transmissions. Other features like start stop systems and electrification of accessory drives will help too. The problem is these features all add cost to the vehicle. If consumers don't buy vehicles equipped with this kind of technology, there is no net benefit. Erni
Earlier this week, after the groundbreaking for Chrysler's new axle plant near Marysville, Michigan, company spokesman David Elshoff spoke to the Worldwide Automotive Report. The new axles to be built at the plant are designed to help improve the fuel efficiency of both the Chrysler and Mercedes cars and trucks they go into.
Late next year, dual clutch gearboxes will cease to be a Volkswagen Group exclusive when Volvo introduces a similar design in their S40/V50 models. The dual clutch gearbox first appeared in the mid-1980s in some Porsche 962 endurance racers and Audi Quattro rally cars. They disappeared through most of the 1990s until a few years ago when they started appearing on some VW and Audi models. Since then they have become a popular option where they're available. Since they're essentially the same as m