Scania has introduced an hydraulic retarder—a form of auxiliary brake for trucks—that automatically disengages and enters a freewheeling mode when not active. This reduces drag losses because both vaned wheels that provide braking power when rotating in oil are disengaged. Actual fuel savings will vary depending on road conditions, but an average of a 0.5% reduction is taken as the rule of thumb.
When braking power is needed, the freewheeling stops and the engagement takes place smoothly and immediately using a type of synchronization that is similar to that in Scania gearboxes. Besides not requiring any energy, the freewheeling retarder also provides higher braking power—4,100 N·m instead of 3,500 N·m—as well as an increased braking effect at lower engine rpm with the help of higher gear ratios.
Reducing fuel consumption is Scania’s main priority. The freewheeling retarder produces further savings that also contributes to an elevated driving experience. The activation of the retarder itself is either initiated by the driver—via a lever on the steering column or with a light touch of the brake pedal—or when the cruise control requests braking. As soon as the retarder is not in use, it freewheels again on its own. But it remains ready to smoothly and firmly change from freewheeling to full braking power in no time.—Örjan Åslund, responsible for Product Affairs at Scania Trucks
Deliveries of the new retarder to customers will begin in the first quarter of 2015.
Separately, the Volkswagen Group has acquired more than 90% of the shares in Scania, enabling it to enact squeeze-out provisions to take full control of the company. The Group has been an investor in Scania since 2000, and held just under 90% until its latest offer. Volkswagen Group is looking at combining Scania with German truck maker MAN and Volkswagen Commercial Vehicles.