JOURNAL OF THE FACULTY OF ENGINEERING AND ARCHITECTURE OF GAZI UNIVERSITY, cilt.24, sa.3, ss.509-515, 2009 (SCI-Expanded)
In automobile engines cam profiles are designed with a particular attention to accomplish a silent operation and long term duration of the valve system. Running of the valve system without vibration as well as satisfying an appropriate lift and lifted-valve period is also related to cam design procedure. In this paper, effects of varying cam profiles on the speed, acceleration and jerk of the followers were comparatively studied. Using a 5(th) order classical spline method, cam profiles were obtained for 2.02 radian (116 degrees), 2.16 radian (124 degrees) and 2.3 radian (132 degrees) lifted-valve periods. For each of these periods cam profiles obtained for 5, 6 and 7 mm cam strokes were compared. For a 5 mm valve stroke and 41.6 mm basic circle diameter 2.02 radian (116 degrees) lifted-valve period provides a reasonable cam profile. However, for a 7 mm cam stroke and 41.6 mm basic circle diameter at least a 2.16 radian (124 degrees) lifted-valve period becomes necessary. If the lifted-valve period is increased to 2.3 radian (132 degrees), the cam profile becomes much better.