In modern car engines, the oscillating masses, the inertia forces of the moving engine parts has to be kept as low as possible. Small oscillating masses are not only the basis for the engine smoothness; they also have a great influence on the reliability and life of the components. The smaller oscillating mass in the crank mechanism minimizes, the weaker the vibrations and reduces friction and wear of the parts.
The contribution of the piston pin to the oscillating mass can be between ten and thirty percent. Mass reduction of the piston pin has a corresponding large effect.
In the newly developed MAHLE composite piston pin, an aluminum core is pressed in a steel sleeve. This enables a weight reduction in the piston pin up to twenty percent for gasoline engines and up to thirty percent for diesel passenger car engines.
As the production of piston pins should be kept simple and economical, the new composite piston pin utilizes a forming process for its manufacturing.
This paper introduces the design principle, the manufacturing process and properties of the composite piston pin.