Traditionally manual clutch actuation for automobiles was a spinoff from hydraulic brake technology namely heavy steel or cast iron cylinders, steel pipes and rubber hoses. Because of this archaic, inefficient and expensive approach to providing a mechanical advantage, an alternative lower cost system of cable operation gained popularity throughout the industry. However, the 1:1 ratio of a cable plus routing problems, NVH issues, efficiency losses and the need for complex adjustment mechanisms, opened up the opportunity for a rebirth of the old hydraulic concept.
The goal was to design a system with a totally new approach that would meet the following criteria: High efficiency, increased temperature resistance, increased durability, reduced package size and weight, cost competitive with cable systems, and finally to take advantage of the latest advances in materials and processes.
This paper will describe the “New Generation Clutch Hydraulic Actuation System” (see Figure 1) from initial concepts, through to the full production stage and acceptance in the automobile industry.