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40KSMEJournal,VolA,No.1,pp.40-47,1990. ANALYTICALANDEXPERIMENTAL MOTION ANALYSIS OFFINGER FOLLOWER TYPE CAM-VALVE SYSTEM WITH A HYDRAULICTAPPET Won-Jin Kim-, Hyuck-Soo Jeon- and Youn-Sik Park- (Received September11,1989) Inthis paper, the motionofa fingerfollower type cam valve system with a hydraulic tappet was analytically and experimentally studied. First, the exact contact point between cam and follower for each corresponding cam angle was searchedbykinematic analysis. Then a 6degree of freedomlumpe- ., u 0 -300 QJ -600 04590135 cam-angIe(deg. ) Fig.11Valve displacement and velocity (camshaft speed2450 rpm) 180 180 -si. -expo 4590135 call1-angleldeg. ) 4590135 cam-angleldeg.) 46 10.0 E 7.5 ., C QJ E 5.0 QJ U l Q. 2.5 tl “U 0.0 0 200 U 100 QJ tl “- E U - 0 ., u 0 -100 aJ -200 0 Fig.9Valve displacement and velocity(camshaft speed600rpm) 400.-, 4590135180 cam-ang1eIdeg.) (h) 4590135180 cam-angleldeg. ) (a) 1600 1200 B800 400 o o 1600 1200 800f 400 o_.L-J:O:C:=.:;-L-“- o 180 4590135 cam-ang e(deg.) o 0.0 10.0- i-2.5 “U !7.5 ., c 5.0 l -400L.-_L_-l._- 180 I 1600 1200 800 - ., u 0-200 QJ 4590135 call1-angle(deg. ) Fig.10Valve displacement and velocity (camshft speed1600 rpm) ANALYTICALANDEXPERIMENTAL MOTIONANALYSISOFFINGER FOLLOWERTYPECAMVALVESYSTEMWITH47 optimize the valve train and cam shape. 6. CONCLUSIONS In this work, a 6 degree of freedom lumped mass-spring- damper model was constructed and its effectivenesswas experimentally verified.Thevarying rocker-arm ratio could be effectively includedindynamicmodelby kinematic analy- sis and its effect could be observed from simulation results of contact force.Thehydrauic tappet model used for the pivot end of oscillating follower was constructed with the aids of experimental data. Consequently, it was foundthatthe con- structed numerical model is quite effectivetopredict finger- follower type OHC valve motion. ACKNOWLEDGMENT This research was supported by Daewoo Motor Co. through a KAIST-Industry Consortium Project. REFERENCES Chan,C.and Pisano,A.,1987,“Dynamic Model of Fluctuat- ing Rocker-Arm Ratio Cam System“, ASME J, Mech. Trans. AutomationinDesign.Vol.109.pp.356-365. Jeon, H.S.,Park,K.J, andPark,Y.S.,1989,“An Optimal Cam Profile Design Considemg Dynamic Characteristics of Cam-Valve System,“ Experimental Mechanics, pp.357-363. Kreuter, P. and Maas,G.,1987,“Influence of Hydraulic Valve Lash Adjusters on the Dynamic Behavior of Valve Trains“, SAE Technical paper No.8?0086. Pisano, A.P. and Freudenstein, F.,1982,“An Experimental and Analytical Investigation of Dynamic Response of a High-speedCam-Follower System.Part1 andPart2“, ASME J,Mech. Trans. Automation in Design,Vol.105,pp.692 -704. Roark,R.and Young,W.,1976,“Formulas for Stress and Strain“, McGraw- Hill. Sakai, H. and Kosaki, H.,1976,“Analysis of Valve Motion in Overhead Valve Linkages-Roles of Valve Spring Surge in Valve Motion“, JoumaJ of the Faculty of Engineering,The University of Tokyo(B), Vol.33,No.4 pp.441-446. Akiba,K.,Shimizu,A.and Sakai, H., “A Comprehensive Simu