Recent Developments in P/M Variable-Valve-Timing Systems for Automobiles  (439KB)
Heinrich Wiedemann, Patrice Delarbre, Bernd Engelmann, Michael Krehl and Lorenz S. Sigl
2002 PM2-Tec Conference, Orlando

The basics and historic developments of variable valve timing (VVT) systems are briefly discussed. VVT systems reduce the fuel consumption and the subsequent formation of exhaust gases and improve the performance of engines, especially the torque characteristics at low rpm. The actual general of VVTs in series production employs the vane-type concept, which uses complex shaped components with tight tolerances. Such parts require materials, which combine moderate strength and high wear resistance with the feasibility for mass-production. These requirements are best met by steels manufactured by the powder metallurgy (P/M) route. Using lean manufacturing processes, P/M steels exhibit all required properties and offer unrivaled economic viability. Thus VVTs are a new and highly attractive market for automotive P/M-suppliers. Finally, an outlook on the market potential for VVTs is given.