Aachen based engineering service provider FEV has developed a cost-effective and compact dual clutch transmission (DCT) for use in city cars. The so-called 5DCT130 transmission offers five speeds plus one reverse speed and is capable of a torque range up to 130 Nm. During the development effort, FEV focused on the combination of available high-volume production components to assure successful series development including short time-to-market.
“Today, the majority of A-segment vehicles are not equipped with automatic transmissions. However, this technology offers a big comfort plus since, in rural driving, many shift and start events occur”, explained Professor Stefan Pischinger, President and CEO of FEV Group. “In combination with proven components, the compact concept of our 5DCT130 transmission meets the individual demands of the A-segment.”
Today, cost-intensive comfort functions and high-end technologies are often foregone in A-segment vehicles. Different concepts are available to increase shifting comfort also in this vehicle segment. “From the perspective of product cost, the automated manual transmission – AMT – has clear benefits compared to a DCT but, because of its design, it presents the disadvantage of rough gear shifts”, explained Dr. Ingo Steinberg, Group Vice President Transmission Systems at FEV. “To address this, we focused on comparing the cost benefit with the potential advantage of the softer powershifts offered by the DCT.” At the same time, the transmission supports fast engine start/stop systems, sailing with the combustion engine turned off, and a park-by-wire function.
Series components as the key to economy
To compensate the disadvantage of the DCT, FEV decided to re-use high-volume production components in developing the 5DCT130 dual clutch transmission, which relies on off-the-shelf parts for most of its components. It also fits within the spatial envelope of a narrow transmission for this vehicle segment, since it only has one output shaft.
FEV’s experts selected a combustion engine-powered pump to realize clutch control and cooling. The solenoids of the compact hydraulic system have been carried-over from the product portfolio of a leading supplier.
A power-on-demand gear actuator in the form of an electro-mechanic off-the-shelf system was well-suited and added the advantage of cost-effective introduction of the park-by-wire function. Apart from the gear actuator, off-the shelf components in the form of the attached control unit, synchronization assemblies, wet dual clutch, differential, series synchronization as well as catalog bearings have been used.
