Optimizing Engine Dynamics with Hydraulic Lash Adjusters in Type-5 Valvetrain Systems Mahindra and Mahindra

Format:

Book

Conference/Event

Author/Creator:

John, Shijino Shaji, author.

Contributor:

Bagal, Pratik

Conference Name:

Off-Highway Technical Conference 2025 (2025-11-06 : Pune, India)

Language:

English

Physical Description:

1 online resource cm

Place of Publication:

Warrendale, PA SAE International 2025

Summary:

For the diesel engines first designed and developed before 2000s, push-rod type valvetrains with mechanical valve lash adjustment were common. For one such legacy diesel engine, first developed for tractors and now applicated for on road vehicles, having push-rod valvetrain architecture and mechanical valve lash adjustment (Type-5 valvetrain system) with flat follower tappet, integrating HLAs for enhancing the NVH and serviceability presented certain challenges. This paper delves into the challenges faced in the design and development phase of HLA integration project on a four-cylinder diesel engine. For integration of HLA, first, the packaging evaluation of valvetrain assembly was done followed by oil flow assessment and necessary changes in the oil pump and circuit. Then, valve lift profile optimizations were done since the ramp rate and seating velocity requirements are different for valvetrains with mechanical lash and HLAs. Numerous iterations were performed for cam-profile design to balance the air flow and volumetric efficiency requirements with the kinematic limitations of higher inertia valvetrain. In parallel, spring force margin was checked for each cam-profile proposal to prevent loss of contact during high speed engine operation and springs with higher preloads and stiffness were evaluated while maintaining the contact stresses at cam nose under material limits. Analytical excel-based calculators were developed for quick first-level assessment of valvetrain kinematics, spring force margin, spring design, cam-profile curve generation from valve lift profile and cam-lobe peak contact stress calculation. For combinations that passed the analytical assessment, 1D simulations were done for checking the engine performance and efficiency while CAE simulation was performed for the valvetrain dynamics. Physical DVP was performed with the finalized valvetrain configuration which included Overloading, High-speed and Cyclic loading tests on engine-level to confirm the performance, functionality and durability with HLA integration

Notes:

Vendor supplied data

Publisher Number:

2025-28-0235

Access Restriction:

Restricted for use by site license