Friction-Aware Optimization of Manufacturable Balancing Cam Profiles for Passive Torque and Velocity Stabilization in Internal Combustion Engines

Torque and angular velocity fluctuations during idle and low-speed operation decrease drivetrain efficiency, increase vibration, and impose irregular loading on coupled systems such as hybrid powertrain generators and conventional transmissions. Building upon a previously validated balancing cam mechanism, this research presents a friction-aware redesign methodology that generates manufacturable cam profiles while preserving the torque characteristics necessary for effective compensation. Two target torque definitions are considered for cam synthesis: a smoothed profile derived from experimentally measured angular velocity and a cycle-resolved profile obtained from engine simulation. To account for friction effects, the selected target torque is reformulated to incorporate the parasitic torque introduced by the mechanism. Manufacturability constraints are then applied to ensure compatibility with the available cam-radius range and follower-stroke limit, while retaining regions of high compensation. The redesigned cam is subsequently implemented on a single-cylinder engine and evaluated through simulations and laboratory measurements. The assessment quantifies torque ripple and angular velocity fluctuation and evaluates the effect of incorporating estimated parasitic torque into cam-profile synthesis. Relative to the previously validated cam profile, the redesigned profile reduced angular-velocity standard deviation fluctuation by 50% and torque peak-to-peak by 44%. These improvements were achieved while maintaining manufacturable geometry and stable follower motion.