DCT Solenoid Development
As more gears are added, the package size of the control solenoid must shrink to fit the same real estate previously occupied by fewer solenoids while the operational requirements remain the same.
As CAFE sets strict standards to reduce emissions and improve fuel economy for passenger vehicles more major automotive companies will look to implement multi-speed dual-clutch transmissions. Dual-clutch transmissions are essentially two separate manual transmissions working as one unit where the gear shifting is carried out by the electrohydraulic components inside the transmission.
TLX Technologies has developed a proportional control solenoid for the electrohydraulic component in dual-clutch transmissions. These proportional control solenoids are used to operate spool valves in the hydraulics of dual-clutch transmissions during gear shifting. Proportional control of the spool valves is required for synchronization of gears during a shift to reduce shift shock. During the development of these proportional control solenoids TLX Technologies encountered multiple challenges which ultimately led to an innovative and efficient design.
One of the major challenges encountered with the design of the proportional control solenoids for dual-clutch transmissions was the overall package size of the solenoid. As automotive companies develop dual-clutch transmissions with more gears, the package size of the control solenoid must shrink to fit in the same real estate previously occupied by fewer control solenoids while the operational requirements remain the same. For example, increasing the number of gears in a dual-clutch transmission from six gears to nine gears reduces the maximum allowable outside diameter of the control solenoid by 30%, which means all of the force producing elements within the solenoid are also reduced. Using magnetic finite element analysis TLX Technologies has been able to model and achieve sufficient magnetic force to shift the hydraulics and maintain proportional control in a small package size by using a combination of radial and conical magnetic designs. The radial part of the magnetic design is used to achieve the high initial force requirement and the conical part of the magnetic design is used to keep the force consistent as the solenoid moves throughout the working stroke of the hydraulics. Using this combination of radial and conical magnetic designs TLX Technologies was able to achieve cycle-to-cycle repeatability of less than +/-0.25% and improve the controllability of the hydraulics in dual-clutch transmissions.
TLX Technologies answers unique system demands with superior electromagnetic solutions. We work with customers to design and develop solenoids and solenoid valves that meet the challenging requirements of their automotive system applications.
***First published in Transmission Technology International magazine, September 2015***