Mechanical Design And Theoretical Analysis Of A Skip-Cycle Mechanism For An Internal Combustion Engine

Abstract

{"references": ["O. A. Kutlar, H. Arslan, and A.T. Calik, \" Methods to improve\nefficiency of four stroke spark ignition engines at part load,\" Energy\nConversion and Management, vol. 46, pp. 3202-3220, 2005.", "O. A. Kutlar, \" A new method to decrease the fuel consumption at part\nload conditions of four stroke Otto cycle (Rochas) Engine-skip cycle\nengine,\" PhD Thesis, Institute of Science and Technology, Istanbul\nTechnical University, Istanbul, 1999 [in Turkish].", "O. A. Kutlar, H. Arslan, and A. T. Calik, \"Skip cycle system for spark\nignition engines: An experimental investigation of a new type working\nstrategy,\" Energy Conversion and Management, vol. 48, pp. 370-379,\n2007.", "M. M. Walsch, \" Valve disabling mechanism,\" U.S. Patent, 4 380 219,\nApril 19, 1983.", "M. B. Diggs, \"Finger follower rocker arm,\" U.S. Patent, 5 653 198,\nAugust 5, 1997.", "G. L. Dyer, \"Camshaft for controlling variably opening valves,\" U.S.\nPatent, 3 986 484, October 19, 1976.", "Y. Ajiki, and M. Matsuura,\"Valve actuating apparatus,\" U.S. Patent,\n4 537 164, August 27, 1985.", "Spring Design Manual, Warrandale, PA : Society of Automobile\nEngineers, 1990, ch. 2", "R. L. Norton,\"Machine Design : An Integrated Approach,\" 3th ed.,\nPrentice Hall, 2005,pp. 739-810\n[10] R. L. Norton, \" Design of Machinery : An Introduction to the Synthesis\nand Analysis of Mechanisms and Machines,\" New York : McGraw-\nHill,1992,ch. 14-17\n[11] H. A. Rothbart, \"Cams : Design, Dynamics, and Accuracy, \" New\nYork : Wiley, 1956,ch.7-8-9.\n[12] F. C. Babalik, \"Makine Elemanlari ve Konstruksiyon Ornekleri,\" \nAnkara : Nobel Yayin Dagitim, 2006, pp. 58-64. [in Turkish]\n[13] A. C. Ugural, \"Mechanical Design : An Integrated Approach,\" Boston :\nMcGraw-Hill /Higher Education, 2004, ch. 14."]}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.