Freewheeling retarder reduces fuel consumption
Commercial Vehicles Safety & Compliance

Freewheeling retarder reduces fuel consumption


Many trucks have some form of auxiliary brakes. For almost two decades Scania’s customers have been able to appreciate just how powerful, yet smooth, effect a hydraulic retarder from Scania can provide. Besides comfort and a relaxing drive, it also provides savings by reducing the need for normal brake system maintenance. In this latest version, the retarder automatically disengages and freewheels when not in use to save on fuel. And it is now even more powerful than before.

One of the Scania Retarder models is now available in a new version (R4100D) 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 half percent reduction is taken as the rule of thumb. 

The driver doesn’t have to do anything. When braking power is needed, the free­wheeling stops and the engagement takes place smoothly and immediately using a type of synchronisation that is similar to that in Scania gearboxes. Besides not requiring any energy, the freewheeling retarder also provides higher braking power, 4,100 Nm instead of 3,500 Nm, 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,” says Örjan Åslund, responsible for Product Affairs at Scania Trucks. “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, says Åslund. 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.” 

Deliveries of the new retarder to customers will begin in the first quarter of 2015.  

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