Roller cam followers for heavy-duty diesels

Mahle engineers applied kinematic and dynamic calculations of the valvetrain as well as finite element analysis to optimize size, weight, and strength of heavy-duty diesel engine components.

Valvetrains with roller camshaft followers are currently normal practice for larger American-made heavy-duty (HD) diesel engines and are increasingly common for European engines. Experts from Mahle Ventiltrieb predict that during the next five years, 40% of the smaller HD diesel engines with an individual cylinder displacement of about 1 L, and nearly 100% of the bigger engines with cylinder displacement of around 2 L, will have rolling contact valvetrain designs. Sliding contact followers are dominant presently in smaller engines and still have a considerable presence in bigger engines.

While roller followers reduce friction and frictional losses, they increase contact stress between the camshaft and follower. In addition, cam profiles must be altered to reach the same valve lift. Despite clear advantages, roller followers have added complexity in function and manufacturing.