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Mechanical Design and Theoretical Analysis of a Skip-Cycle Mechanism for an Internal Combustion Engine

Authors: Ismail Gerzeli, Cemal Baykara, Osman Akin Kutlar


Skip cycle is a working strategy for spark ignition engines, which allows changing the effective stroke of an engine through skipping some of the four stroke cycles. This study proposes a new mechanism to achieve the desired skip-cycle strategy for internal combustion engines. The air and fuel leakage, which occurs through the gas exchange, negatively affects the efficiency of the engine at high speeds and loads. An absolute sealing is assured by direct use of poppet valves, which are kept in fully closed position during the skipped mode. All the components of the mechanism were designed according to the real dimensions of the Anadolu Motor's gasoline engine and modeled in 3D by means of CAD software. As the mechanism operates in two modes, two dynamically equivalent models are established to obtain the force and strength analysis for critical components.

Keywords: Dynamic Model, Mechanical Design, Skip Cycle System (SCS), Valve Disabling Mechanism

Digital Object Identifier (DOI):

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[1] O. A. Kutlar, H. Arslan, and A.T. Calik, " Methods to improve efficiency of four stroke spark ignition engines at part load," Energy Conversion and Management, vol. 46, pp. 3202-3220, 2005.
[2] O. A. Kutlar, " A new method to decrease the fuel consumption at part load conditions of four stroke Otto cycle (Rochas) Engine-skip cycle engine," PhD Thesis, Institute of Science and Technology, Istanbul Technical University, Istanbul, 1999
[in Turkish].
[3] O. A. Kutlar, H. Arslan, and A. T. Calik, "Skip cycle system for spark ignition engines: An experimental investigation of a new type working strategy," Energy Conversion and Management, vol. 48, pp. 370-379, 2007.
[4] M. M. Walsch, " Valve disabling mechanism," U.S. Patent, 4 380 219, April 19, 1983.
[5] M. B. Diggs, "Finger follower rocker arm," U.S. Patent, 5 653 198, August 5, 1997.
[6] G. L. Dyer, "Camshaft for controlling variably opening valves," U.S. Patent, 3 986 484, October 19, 1976.
[7] Y. Ajiki, and M. Matsuura,"Valve actuating apparatus," U.S. Patent, 4 537 164, August 27, 1985.
[8] Spring Design Manual, Warrandale, PA : Society of Automobile Engineers, 1990, ch. 2
[9] R. L. Norton,"Machine Design : An Integrated Approach," 3th ed., Prentice Hall, 2005,pp. 739-810
[10] R. L. Norton, " Design of Machinery : An Introduction to the Synthesis and Analysis of Mechanisms and Machines," New York : McGraw- Hill,1992,ch. 14-17
[11] H. A. Rothbart, "Cams : Design, Dynamics, and Accuracy, " New York : Wiley, 1956,ch.7-8-9.
[12] F. C. Babalik, "Makine Elemanlari ve Konstruksiyon Ornekleri," Ankara : Nobel Yayin Dagitim, 2006, pp. 58-64.
[in Turkish]
[13] A. C. Ugural, "Mechanical Design : An Integrated Approach," Boston : McGraw-Hill /Higher Education, 2004, ch. 14.