Continental Using BASF’s Ultramid Plastic in Latest Control Units for Dual-Clutch Transmission

30 March 2009

The plastic parts of the integrated control units for dual-clutch transmissions produced by Continental for use at VW, Audi, Ford and BMW are made of Ultramid A3WG6, a proven PA 66 produced by BASF. This material is highly heat-stabilized, oil-resistant and, if needed, laser-markable.

The transmission control unit is a sophisticated, compact mechatronic component that is installed directly on the transmission and is thus also surrounded by hot transmission oil. Consequently, the main requirement made of this plastic part—into which numerous sensors, molded interconnect devices and other metallic structures have to be securely integrated—is that it has to be chemically resistant to transmission oil within the temperature range from -40 °C to +145 °C (-40 °F to +293 °F). It even has to be able to withstand brief peak temperatures of up to +170 °C (+338 °F) without being damaged.

In this context, transmission oils pose a challenge since they are considerably more aggressive and less standardized than motor oils. But even under such harsh conditions, the material has no problem ensuring the requisite high level of dimensional stability of the plastic parts.

The dual-clutch transmission consists of two separate clutches, each driving specific gears. The main task of the electronic control unit is to ascertain the next gear needed as a function of the driving circumstances so that it can then engage one clutch and disengage the other. When the gear is being shifted, the next gear is already selected in the not-yet active transmission part before the actual shifting operation. This accounts for smooth gear shifting, without any interruption of the power transmission. Not least due to the intelligent control unit, it is now possible to further improve the efficiency of these transmissions and to cut fuel consumption to a level that is even lower than that of a manual transmission.