Changing gears in transmission design
Transmission design is becoming more challenging – and interesting – as manufacturers gear up to cater for a growing variety of power plants and hybrid vehicles.
One of the leaders in the field is Getrag. Its PowerShift transmission was first fitted to the Mitsubishi Lancer Evo X, introduced end of 2007. Since then, Ford has introduced the PowerShift transmissions with the Focus and C-Max models, Volvo received good press feedback for its V50 and Chrysler offers Journey and Sebring models for the European market with PowerShift transmission. BMW had also great response for its new M3, which came to market in spring 2008.
Automotive Industries (AI) asked Chief Operating Officer Bernd Eckl what prompted BMW to select the first inline dual–clutch transmission for high – revolution engines.
Eckl: The 7DCI600 is the perfect fit for the high-revving engine of the M3. The compact size and high input torque capacity of up to 600Nm, the ratio flexibility given by the layshaft principle that allows the gears to perfectly adapt to the engine characteristics and delivers superior mechanical efficiency at minimal drag torque losses also the very flexible software allows the definition of a lot of strategies and launch characteristics.
AI: What other will we see?
Eckl: By the end of next year, we will introduce the dry PowerShift. This transverse application has a dry dual clutch and electromechanical actuation. It is capable of up to 250Nm.
AI: Are there any concepts for a hybrid version?
Eckl: We are very flexible regarding the connection of the e-motor to the transmission. We designed an axially parallel arrangement of the e-machine to one part-transmission of the PowerShift gearbox. This enables high revolution concepts and optimum operating conditions for the e-motor. There are designs for both inline and transverse versions and the flexible mounting of one or two e-machines allows mild-or full hybrid solutions with a lot of technical synergies.
AI: What about the electric axle drive?
Eckl: This so-called through-the-road hybrid combines the benefits of a hybrid system with the benefits of an all-wheel drive system. With electric axle drives, the costs are moderate, minimal space is needed for application, and there are only minor interactions with the conventional components of the vehicle.
AI: What other Powershift transmissions are coming to market?
Eckl: The new BMW 335i Coupé and Convertible. Both are very dynamic cars that are a real pleasure to drive with the inline PowerShift 7DCI600. The 7DCL750 PowerShift, a transmission for super sports cars with transaxle longitudinal design will come to market with the new Ferrari California and there are further applications for our existing customers: Ford, Volvo and Mitsubishi.
AI: What can we expect from Getrag in future?
Eckl: The next generation of PowerShift transmissions will achieve even greater fuel efficiencies. We will also expand the e-Drive business area.
AI: What is the future of the pure electric vehicles?
Eckl: We will see a shift in the end consumer’s view of mobility. There will be more specialized types of vehicles, such as electric vehicles for inner city or short distance leisure and delivery traffic, because an action range of 200km a day is sufficient for many of today’s car drivers. For all other purposes we will have conventional or hybrid powered vehicles.
AI: What are your efforts in this field?
Eckl: We are involved in the e-smart activities and have different customer projects running for battery electric vehicles. Think of small commercial vehicles for urban delivery services and lifestyle oriented cars. Therefore, we feel that Getrag is prepared for the future with its more diversified mobility concepts, as they have all one thing in common: it is all a matter of efficiency.