Weight and Drivetrain optimization via Fuel pump & Vacuum Pump drive by engine camshaft in a pushrod type valve actuated engine.

Optimizing weight, cost and friction is critically focused in most modern powertrains. Lesser components in drive trains makes the systems` lightweight and more efficient. This paper explains the idea of integrating a fuel pump and a vacuum pump drive system on to the main camshaft eliminating many rotating & static parts in a two valve per cylinder push-rod type actuated 4-cylinder diesel engine, thereby reducing overall weight, cost and drive losses. The modified camshaft will now drive oil pump, vacuum pump, fuel pump and valve train together. The existing camshaft is extended with a slot at one end and a three lobed cam made of higher grade material is press fitted on to the said portion with an additional journal bearing face added. Proposed camshaft design is evaluated for handling higher power transmission considering multiple drives are connected. Design verification simulations are run including High cycle fatigue, camshaft bearing EHD, Timing drive dynamics to ensure all functions and safety factors are kept intact. Subsequent physical validations like over-load testing and cyclic load testing is cleared, proves the design robustness and reliability. In the due course of development, many design improvements are further added to increase the camshaft fatigue life and strength. Almost all design changes has ensured each of the critical failure modes covered. Approximately 7kg weight saving is realized and subsequently reflected in reduced costing. This concept has also helped to factor out reduced service cost. Fuel pump and Vacuum pump drive integrated common camshaft concept eliminates one of major sub-assembly stations in the production unit, simplifies the manufacturing process and reduced over-all assembly takt time, hence DFM-design for manufacturing added value.