International Journal of Scientific Engineering and Technology (ISSN : 2277-1581) Volume No.4 Issue No.3, pp: 212-217 01 March. 2015 IJSET@2015 Page 212 Design of Innovative Engine Valve S. M. Muzakkir*, M. G. Patil and Harish Hirani Department of Mechanical Engineering, Indian Institute of Technology Delhi, India *Corresponding Author Email:mez108659@mech.iitd.ac.in Abstract: This is part two of the paper on conceptual design of an engine valve. The previous paper describes the background and the need of an engine valve for an internal combustion engine. The present state of the engine valve technology and the innovations incorporated in its design has been described. This paper presents the conceptualization of an innovative valve train aiming at lesser number of components, reduction in friction and wear, proper sealing, and trimming down pumping losses. Various geometric designs of valve trains have been detailed and compared. Finally a convolution based poppet valve mechanism, which is free from numerous mechanical elements like camshaft, cam, push rod, rocker arm and rocker bearing has been recommended. Finite element analysis of convoluted spring has been carried out to ascertain safe limits in terms of stresses and achieving desirable valve lift. Magnetorheological fluid and electromagnet are used to vary the valve-lift. Keywords: Innovative Design, Variable valve actuation mechanism, cam-less engine valve, Magnetorheological fluid. I. Conceptual Design of Engine valve A review of literature has indicated a definitive trend of replacement of cam-pushrod valve train with direct-overhead- cam valve train. Another trend observed is in the reduction of reciprocating masses to minimize friction and wear losses. There is also an observable trend to eliminate mechanical cam drive with hydraulic, electromechanical or electromagnetic drive system. Such trend analysis indicates the possibility of a new valve mechanism as shown in Fig. 4. In the present work three valve train designs have been conceptualized, which are described below. Concept 1: Rotary valve with magnetorheological fluid: Rotary valves [14], used for internal combustion engines 1976 [14] proved to be theoretically to reduce losses, but could not take off due to limited sealing characteristics. Recently Paul [15] presented rotary valve assembly with a variable timing control to make rotary valve suitable variable valve actuation. A schematic of such a rotary valve is shown in Fig. 1.The amount of overlap between core and throttle body subassembly reduces or increase the area available for fresh charge. Figure 1: Rotary valve [17] To overcome the drawback of sealing, rotary valve with magnetorheological fluids, shown in Fig. 2, has been hypothesized in the present study. Figure 2: Sketch showing MR fluid, cylinder head and valve A Magneto-Rheological fluid (MR fluid) is a suspension of micrometer-sized magnetic particles in a carrier fluid, and acts as a smart fluid. On subject to magnetic field, the fluid greatly increases its viscosity. Importantly, the yield stress [16] of the fluid when in its active state can be controlled very accurately by varying the current supplied to electromagnetic coils. As shown in Fig. 2, the hypothesized rotary valve has a slot to pass fresh charge to the cylinder. When this slot coincides with the opening in the cylinder head, fluid flow (charge) takes place. MR fluid filled in the space between the rotary valve and cylinder head provides tight sealing and does not allow rotary valve and seat to wear out.