Active driveline

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Land Rover Range Rover Evoque (2012 model, 3-door)

The Active Driveline is an all-wheel drive technology from the car manufacturer Land Rover . The system combines the functions of all-wheel hang-on clutch, transverse limited slip differential and torque vectoring (yaw support when cornering) with the greatest possible shutdown of the drive train if necessary. Compared to conventional hang-on all-wheel drive, the vehicle behavior ( traction and handling) is improved and fuel consumption / CO2 emissions are reduced.

Name Active Driveline

While Land Rover prefers the term Active Driveline, the supplier GKN Driveline markets the all-wheel drive concept used under the name Eco Twinster. The partial formulation "Eco" covers the function of the adaptive all-wheel disconnection, which is also regularly referred to as disconnect in the relevant specialist literature and is intended to ensure an improved ecological balance of the vehicle by reducing power loss. The trademark "Twinster" with a copyright stands for the implementation of torque vectoring via two separately hydraulically operated friction plate clutches. Due to the fact that both couplings are identical, the English translation for the German term twin was used. However, from a promotional point of view, the linguistic proximity to the word "Twister" as a name for a storm does not appear to be disadvantageous for the manufacturer.

Due to the relatively specific features of the overall concept, it is conceivable that if the technology is implemented, a proprietary name that is independent of the manufacturer will be created. However, this has not yet been clearly done in the industry, but the positive expression “Active”, which is in contrast to “Disconnect”, seems to be establishing itself. This is how the automobile manufacturer Jeep names its basically similar all-wheel drive implementation with Active Drive.

functionality

Twinster coupling

The principle is essentially based on a double function of the Twinster clutch. On the one hand, the Twinster replaces the positive torque transmission of a classic mechanical differential gear with a frictional connection via two friction plate clutches, which in the sense of a torque distribution - resp. Yaw control can be activated according to the driving situation. This is intended to generate less power understeer when cornering, since the torque is individually transmitted with precision via an autarkic electronic control unit if required. This wheel-selective torque distribution enables, on the one hand, yaw support when cornering (the wheel running inside the curve receives less torque) and, on the other hand, the traction behavior is significantly improved, since it also represents a lateral function. If both clutches are closed, this corresponds to a vehicle with a 100% locked distributor and rear axle differential. With regard to the actuators, GKN Driveline expanded its product range to include the variant of an electro-hydraulic actuator. The wet friction clutches are acted upon by hydraulic pressure, which is generated by a motor-pump combination and metered via two pressure control valves. The advantage over electro-mechanical energy conversions, for example, is that the spatial allocation in the vehicle can be designed very variably. The system is also able to engage all-wheel drive within 300 ms.

Adaptive all-wheel drive

On the other hand, the clutches represent the interface for deactivating the drive train in the rear axle by interrupting the frictional connection if necessary. As a result, a compact and efficient system with as few components as possible was developed, as no potentially complex mechanical decoupling of the drive train is necessary in the rear axle. With regard to the disconnection of the cardan shaft required in the front axle, a conventional solution was chosen. A mechanical synchronization built into the PTU is used here, through which the masses can be accelerated separately or even independently of the wheel. The actuation takes place via the same actuators that are already used for the Twinster clutches. By switching it on and off as required, the additional fuel consumption of the all-wheel drive system can be reduced by up to 80%, as the drag torques are considerably reduced. In a prototype vehicle, a consumption advantage of 0.54 l per 100 km was demonstrated in the NEDC. This corresponds to a CO 2 saving of 14.2 g per km.

history

The concept of the Active Driveline was developed by the Baden-Wuerttemberg automotive supplier Getrag , the later implementation basically only includes the constructive adaptation to the customer Land Rover. The system was presented to the public for the first time in 2011 in the Automobiltechnischen Zeitschrift (ATZ). In this and other publications, Getrag always saw the adaptive all-wheel drive system as the answer to the tightening of the CO 2 regulations that was already emerging at the time .

With regard to the “Twinster clutch” module used in the Active Driveline, a general increase in marketing was carried out. In 2004, Getrag developed an all-wheel drive system with Twinster based on the Mini Cooper S. By installing the Twinster clutch in the already very agile BMW Mini, the prototype was intended to demonstrate a further increase in driving safety and dynamics through the pronounced yaw control . The trade press reacted positively to this and certified the vehicle to understeer significantly less when cornering and to behave much more neutrally, which goes hand in hand with the subjective feeling of greater driving pleasure.

In 2011, GKN Driveline took over the Driveline Products division of Getrag KG and thus also the further development of the Active Driveline. The technology's preliminary breakthrough came in 2013 when it was used in series production in the Range Rover Evoque , which combines its 2.0 liter petrol engine with the Active Driveline, while the diesel variants use conventional all-wheel drive. In the Range Rover Discovery Sport, model year 2015, the Active Driveline is offered for the powerful diesel engines (optional) and the gasoline engine (standard). The Active Driveline was largely recognized as an innovation at the time of its introduction, so the system made it into the circle of finalists for the awarding of the Pace Awards 2014. The developers felt confirmed by the competition, which systems for decommissioning the propshaft also in their portfolio Recordings. In fact, the Jeep Cherokee appeared on the market as the first supplier of a disengageable all-wheel drive, the series launch of the all-wheel drive produced by the supplier American Axle & Manufacturing came in 2013 a few weeks before the Land Rover Evoque was presented.

Web links

Individual evidence

  1. ↑ Article on Auto.de: Powertrain Innovations - Increased Dynamics.Retrieved on November 23, 2014
  2. ↑ Information from the manufacturer Jeep: Explanations about the Jeep Allrad  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. Retrieved November 23, 2014@1@ 2Template: Dead Link / www.jeep.de  
  3. ^ Technical article in the ATZ - Automobiltechnische Zeitschrift, issue no .: 2011-10
  4. ^ Technical article in the ATZ - Automobiltechnische Zeitschrift, issue no .: 2011-10
  5. ↑ Article on Autobild.de: Driving report Mini Twinster Retrieved on November 23, 2014
  6. ↑ Press release from GKN Driveline: Takeover of Getrag Driveline Products ( Memento of the original from March 4, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved November 23, 2014 @1@ 2Template: Webachiv / IABot / media-centre.gkndriveline.com
  7. ↑ Information from the manufacturer Range Rover: Explanations for the Range Rover Evoque all-wheel drive. Accessed on November 27, 2014
  8. ↑ Information from the manufacturer Range Rover: Explanations for the Range Rover Discovery Allrad.Retrieved on November 25, 2014
  9. ↑ Article on Autonews.com: PACE Award Finalists of the Year 2014 ( Memento of the original from November 21, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Retrieved November 27, 2014 @1@ 2Template: Webachiv / IABot / www.autonews.com
  10. ↑ Article by Green Car Congress.com: First introduction of a disused all-wheel drive.Retrieved on November 20, 2014