LuK GmbH & Co. KG · Germany

• Company
• Worldwide Locations
• Products
• Services
• Press Office
  • Press releases
  • Press media
  • NAIAS Press Kit
  • IAA Press Kit
• Careers
• Events
• Suppliers
• Sales

2010-01-27 | 000-002-204 DE-EN
LUK GMBH & CO. OHG, BÜHL, BADEN

Minor cause — major effect

Modern consumers purchasing new-generation vehicles have come to view a sporty yet comfortable driving experience and low emission statistics for CO2 and other harmful substances as standard requirements. A promising solution to implement these requirements is the so called start-stop-system that shuts down the engine when the vehicle is at a standstill. As soon as the driver depresses the clutch pedal, the system automatically restarts the engine. Driving comfort and safety remain consistent. Currently only 2 percent of all vehicles on the market are equipped with the start-stop-system, but this number is going to increase considerably in the next years. In order to ensure a optimal performance, the vehicles continuously needs information about the adjustment travel of the hydraulic actuating cylinders. Here, the newest innovation of LuK GmbH & Co. oHG, a clutch cylinder with sensor, takes action. This product started successfully in serial production at Volkswagen and also promises huge potential for other car manufacturers.

With such demanding goals to be met, simply optimising individual components has long since ceased to be sufficient; what is needed is an overhaul of the entire system. A specialist team at LuK GmbH & Co. oHG has been working on release sys-tem development for over ten years now. The latest innovation to be born out of this work is the clutch cylinder featuring extensometer technology; it is currently being used successfully in series production at VW and looks set to yield great potential for other vehicle manufacturers too.

As the heart of the entire clutch and actuation system and the link between the pedal and clutch, the release system has a decisive influence on driving feel. Among the criteria to be fulfilled are smooth disengagement, actuation-friendly force-travel characteristics at the pedal, noise-free, vibration-free actuation and pleasant modulation properties when moving off and changing gear. The entire system needs to function perfectly under all operating conditions as well as ensuring optimum interplay with the other vehicle components.

Vehicles with start/stop functionality, automated transmissions and automatically actuated clutches in hybrid vehicles require information about the positioning travel of the hydraulic actuating cylinder in order to deliver optimum performance. The system developed by automotive supplier LuK to provide this information comprises extensometers fitted in the hydraulic clutch operation system. When used on the clutch master cylinder, the applications of this kind of sensor technology include promptly identifying driver requirements, which is a vital function for the existing start/stop systems. When fitted to the clutch slave cylinder, however, extensometers are used primarily for automated transmissions, certain hybrid drive configurations and double clutch transmissions, where they ensure accurate clutch control.

Baden-based automotive supplier LuK offers products to fulfil both of these requirements. The sensors used to relay the information feature non-contact technology, using a magnet attached to the hydraulic piston as their target. The benefit of this approach for automotive manufacturers is that the cylinder and sensor can be purchased as a pre-assembled solution. The two components form a pre-calibrated, pre-tested unit and each unit has its own unique marker, guaranteeing that LuK will be able to track the products even years down the line.

"The release system with extensometer is yet another innovation that LuK is proud to unveil", verifies Roland Welter, who heads up the release systems product line. "Over ten years, LuK has acquired a wealth of expertise in release systems, and our experience is brought to bear once more with this new product."

Depending on the type of electronics used, measurement is accurate to approx. +/- 3% and the sensor can withstand usage temperatures ranging from -40°C to +120°C with short-term temperature spikes of up to +160°C. This product has huge potential — as well as being used in series production at VW it has consolidated its position in the highly competitive market.

SERVICE

CONTACT