Lightweight valves

The performance of a valve train system is mainly determined by the oscillating moved masses. As a result, the stiffness of the complete valve train must for instance be increased for high-speed engines. Alternatively, the mass of the valves can be reduced, as the largest part of the moved mass in the cylinder head.








Thanks to more lightweight valves, it is also possible to achieve more lightweight and cost-effective designs for cam lobes, cam followers, tappets, and springs at the same engine speed level, while also improving fuel consumption and engine noise development.

MAHLE has systematically examined material and design approaches for more lightweight valves. The results of this extensive development work are the new MAHLE lightweight valves made from sheet metal, which enable a weight reduction of up to 50 percent in comparison to conventional solid stem valves. Besides a reduction of the moved mass in the valve train, this development also results in a lower static mass of the engine. The lightweight valves significantly reduce the wear at the valve seat and valve seat insert. In respect to the weight tolerances as well, the new valves reveal considerable advantages through a very low dispersion.

The new MAHLE lightweight valve is a welded hollow structure made from cold formed steel sheet parts. The connection between the plate and shaft tube, which effectively absorbs the combustion chamber pressure and lateral forces, ensures the highest stability. Neither the very precise laser welded joints nor the cold formed sheet metal parts require an additional mechanical reworking - only the functional areas are still ground. Due to its stable design, the lightweight valve can withstand very high ignition pressures. With the exhaust valves, sodium can be introduced into the hollow structure for reducing the valve temperatures before welding on the valve tip. A technique which is especially used in turbo- charged engines and is suited for exhaust gas temperatures beyond 1,000 °C.