Refine Your Search

Search Results

Viewing 1 to 3 of 3
Journal Article

New MAHLE Steel Piston and Pin Coating System for Reduced TCO of CV Engines

Abstract Total cost of ownership is requiring further improvements to piston friction reduction as well as additional gains in thermal efficiency. A piston compression height reduction in combination with carbon based piston pin coatings is enabling advancements in both demands. MAHLE implemented a new innovative metal joining technology by using laser welding to generate a cooling gallery. The MonoLite concept offers design flexibility which cannot be matched by any other welding process. Especially an optimum design and position of the cooling gallery as well as durability for very high peak cylinder pressures can be matched. This is particularly advantageous for complex combustion bowl geometries that are needed in modern diesel engines to meet fuel economy and emission requirements. The MonoLite steel piston technology offers a superior compression height reduction potential compared to typical friction welded designs.
Technical Paper

Composite Piston Pin, A New Lightweight Design Concept

Abstract 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.
Technical Paper

Cast-In Cylinder Liners Designs to Improve Bonding and Shear Strength for Aluminum Block

The tendency to use aluminum alloys to replace conventional gray cast irons (GCI) materials in engine blocks of passenger cars is gaining more and more importance driven by reduction of engine weight to achieve expectation for lowering fuel consumption and CO₂ emissions. Cast-in cylinder liners are commonly applied inside of aluminum engine blocks with designs of the outer surface usually selected through analysis of the aluminum casting process (e.g., high pressure die casting, precision sand cast), geometry complexity, thermal and mechanical loads. A good quality of clamping (bonding and shear strength) between the cast-in cylinder liner and aluminum block might guarantee a reliable heat transfer and thus low bore distortion. The good clamping can also contribute to improve the final machining of the liner after block casting. The most effective variants of cast-in cylinder liner designs were selected for the evaluation of clamping performance.