All-plastic manual-clutch actuation

Engineers at Automotive Products are developing the relatively new material application for improved economy, smaller engine compartments, and new vehicle concepts such as hybrids.

When all-plastic hydraulic-actuation systems for manual clutches appeared in the early 1990s, they gave automakers a lighter, less costly, easier to use, and more reliable system than cable-actuated clutches. Given these benefits, plastic systems are used in about 60% of all manual-shift vehicles made in the U.S. (about 12% of U.S. auto output), and their use is growing at a double-digit rate in many other countries. In 1999, about 1.5 million such systems were installed in cars and light trucks worldwide.

Although some use of plastics in hydraulic manual-clutch actuation dates to the early 1980s, it was not until plastic master and slave cylinders were developed that all-plastic actuation became possible. These cylinders, which used bodies of Ticona's Celstran long glass-fiber-reinforced nylon 6/6 to provide essential burst strength, first appeared in MY 1992. Today all-plastic systems are found in many passenger vehicles and light trucks, including the Ford Ranger and F150 and the Rover 75 and Freelander (Figure 1).