Transmission specialist Oerlikon Graziano, part of Oerlikon’s Drive Systems Segment, is presenting its innovative 4SED (4 Speed Electric Drive) to customers around Europe. This new compact, lightweight transmission boasts increased efficiency, seamlessly smooth shifting and a scalable design making it suitable for a wide range of vehicle types. “This is a fully new transmission concept which will advance the development of electric vehicles”, says Heriberto Diarte, CEO of the Drive Systems Segment.
Oerlikon Graziano, with more than 20 years of experience in electric and hybrid drivetrain design and manufacture, proactively developed the 4SED transmission in anticipation of market need for increasingly efficient transmissions for low and zero emission vehicles. The mechanical design concept has been developed by Oerlikon Graziano, while the shift control system was engineered by UK controls specialist Vocis Driveline.
The 4SED, based on Graziano and Vocis’s original eDCT, uses two traction motors in a very compact powertrain which provides four speeds to allow running closer to peak efficiency – approximately 90 percent. The result is an overall efficiency improvement of up to 15 percent, which translates into increased range or improved performance for the vehicle.
“The design of the gearbox is very simple”, says Paolo Mantelli, Head of Oerlikon Graziano Performance Automotive. “The transmission’s unique configuration uses two input shafts, each driven by its own electric motor. The two motors replace the twin clutches and the synchronizers, allow pre-selection of the next gear before the previous one has been disengaged, and can synchronize shaft speeds”. The use of the traction motors also permits a reduced set of software algorithms compared to a normal automated gearbox, and since there are no hydraulics, there is no need for valve control.
“The technology is scalable to suit a wide range of different vehicle types, urban electric cars, high performance cars, hybrid 4WD applications, electric buses and trucks. It is also suitable for applications with 48V motors, allowing significant cost savings and reducing risks of high voltage 4SED speaks for itself”, continues Mantelli, “it is seamless, it is clutch less, it needs no synchronizer and is truly innovative!”.
A demonstrator has been fitted to an electric Mercedes Vito minibus and is currently touring renowned European vehicle manufacturers to showcase its unique features. Initial customer feedback is very positive: “As a first demonstrator the shifting function is very impressive, there is no feeling of torque interruption and they are very smooth”. “This transmission is perfectly scalable to the needs of the customer through different platforms and performance requirements”.
More details on this innovative 4SED will follow at CTI symposium in Berlin in December 2013.
Source: Oerlikon Graziano
The fact that there is no hydraulics or clutches is a competitive edge against other transmission technologies. Do you think it is feasible from a comfort and controllability point of view to put an electric motor on an input shaft and a thermal engine on the other input shaft of this transmission?