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 ¨C AMT ¨C 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.
