We present a methodology to design cams for motor engine valve trainsusing a constrained optimization algorithm. The imposed constraints arethe maximum valve lift and timings while the objective function is tomaximize the time integral of the valve area opened to gas flow. Apiecewise analytically defined acceleration is imposed, so that the timeinstants controlling the profile of accelerations are used as variablesfor optimization. The strategy takes into account some geometricalconstraints, e.g. to avoid interference between intake and exhaustvalves, and between valves and piston. Also, minimum and maximum levelsof acceleration are limited to avoid excessive forces in the mechanismschain, and to prevent the possibility of separation between cam andfollower. Once an optimal lift profile is determined, the cam shape iscomputed using an inverse kinematics analysis that takes into accountall the geometric nonlinearities introduced by the kinematical chain.Finally, the whole mechanism is verified in a dynamics analysis to checksatisfaction of the criteria for design. Comparisons with standardprofiles of motion were made. Also, the profile was evaluated in anexperimental device, where the actual valve displacement was measured.
This is a preview of subscription content,to check access.
Access this article
Bagci, C. and Kurnool, S., 'Exact response analysis and dynamic design of cam-follower systems using Laplace transforms', Journal of Mechanical Design 119, 1997, 359-369.
Cardona, A. and Géradin, M., 'Kinematic and dynamic analysis of mechanisms with cams', Computer Methods in Applied Mechanics and Engineering 103, 1993, 115-134.
Cardona, A., Géradin, M. and Doan, D., 'Rigid and flexible joint modelling in multibody dynamics using finite elements', Computer Methods in Applied Mechanics and Engineering 89, 1991, 395-418.
Farouki, R., Mandunathaiah, J. and Jee, S., 'Design of rational cam profiles with Pythagoreanhodograph curves', Mechanics Machine Theory 33, 1998, 669-682.
Grewal, P. and Newcombe, W., 'Dynamic performance of high-speed semi-rigid follower cam systems-Effects of cam profile errors', Mechanics and Machine Theory 23, 1988, 121-133.
Hanachi, S. and Freudenstein, F., 'The development of a predictive model for the optimization of high-speed cam-follower systems with Coulomb damping internal friction and elastic and fluidic elements', Journal of Mechanisms, Transmissions, and Automation in Design 108, 1986, 506-515.
Heizler, H., Advanced Engine Technology, SAE International, Warrendale, PA, 1995.
Heywood, J., 'Fluid motion within the cylinder of internal combustion engines-The 1986 Freeman Scholar Lecture', Journal of Fluids Engineering 109, 1987, 3-35.
Lin, Y., Hodges, P. and Pisano, A., 'Optimal design of resonance suppression helical springs', Journal of Mechanical Design 115, 1993, 380-384.
Lin, Y. and Pisano, A., 'General dynamic equations of helical springs with static solution and experimental verification', Journal of Applied Mechanics 54, 1987, 910-917.
Lin, Y. and Pisano, A., 'Three-dimensional dynamic simulation of helical compression springs', Journal of Mechanical Design 112, 1990, 529-537.
Mosier, R., 'Modern cam design', International Journal of Vehicle Design 23, 2000, 38-55.
Neamtu, M., Pottmann, H. and Schumaker, L., 'Designing NURBS cam profiles using trigonometric splines', Journal of Mechanical Design 120, 1998, 175-180.
Pisano, A. and Freudenstein, F., 'An experimental and analytical investigation of the dynamic response of a high-speed cam-follower system. Part 2: A combined, lumper/distributed parameter dynamic model', ASME Journal of Mechanisms, Transmissions, and Automation in Design 105, 1983, 699-704.
Samtech, Samcef-Mecano, User Manual, Samtech, Liège, Belgium, 1996.
Schamel, A., Hammacher, J. and Utsch, D., 'Modeling and measurement techniques for valve spring dynamics in high revving internal combustion engines', in Design of Racing and High Performance Engines, J. Harralson (ed.), Vol. PT-53, SAE, Warrendale, PA, 1995, 83-99.
Srinivasan, L. and Ge, Q.J., 'Designing dynamically compensated and robust cam profiles with Bernstein-Bézier harmonic curves', Journal of Mechanical Design 120, 1998, 40-45.
Taylor, C., The Internal Combustion Engine in Theory and Practice, MIT Press, Cambridge, MA, 1984.
Tsay, D. and Huey Jr., C.O., 'Application of rational B-splines to the synthesis of cam-follower motion programs', Journal of Mechanical Design 115, 1993, 621-626.
Ñnlüsoy, Y. and Tümer, S., 'Analytical dynamic response of elastic cam-follower systems with distributed parameter return spring', Journal of Mechanical Design 115, 1993, 612-620.
Ñnlüsoy, Y. and Tümer, S., 'Nonlinear dynamic model and its solution for a high speed cam mechanism with Coulomb friction', Journal of Sound and Vibration 169, 1994, 395-407.
Wiederrich, J. and Roth, B., 'Dynamic synthesis of cams using finite trigonometric series', Journal of Engineering for Industry 97, 1975, 287-293.
Yu, Q. and Lee, H., 'Influence of cam motions on the dynamic behavior of return springs', Journal of Mechanical Design 120, 1998, 305-310.