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The Dynamics of Valvetrains with Hydraulic Lash Adjusters and the Interaction with the Gas Exchange Process
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Abstract
Models are presented for:
- (i)the dynamics of valvetrains with hydraulic lash adjusters. The effects of the adjuster can be split, the elasticity being included in the dynamics model, and the leak-down solved explicitly. This eliminates the numerical difficulties encountered with straightforward formulations.
- (ii)the gas force on exhaust valves. The exhaust flow and the valve dynamics are solved simultaneously to obtain the full effect of cam modifications. Advantage is taken of the positive displacement flow in four-stroke engines to avoid numerical difficulties associated with throttling flow.
- (iii)the efficient generation of accurate lift curves for gas exchange predictions.
In this paper we describe developments of a model for the dynamics of valvetrains /13/* presented at this Congress two years ago. This model was very successful for mechanical valvetrains under the action of spring and inertia forces. Numerical difficulties were, however, encountered when simulating valvetrains with hydraulic lash adjusters. Moreover, no model was available to simulate the gas force on exhaust valves, a third important source of valve vibrations. This caused us to study the properties of valvetrains with hydraulic lash adjusters, and to examine the effect of the exhaust flow on valve dynamics. Finally, we show that the small deviations of the valve lift from the kinematic lift have a substantial effect on the gas exchange, both at idle and full load. We therefore outline a simple model, based on what we learned for the detailed dynamics model, for generating accurate valve lift curves.
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Phlips, P. and Schamel, A., "The Dynamics of Valvetrains with Hydraulic Lash Adjusters and the Interaction with the Gas Exchange Process," SAE Technical Paper 910071, 1991, https://doi.org/10.4271/910071.Also In
References
- Bakaj, L.F. 1988 “Rechnerische Simulation der Ventiltriebsdynamik eines OHC-Schlepphebelventiltriebes mit hydraulischen Ventilspielausgleich” Karlsruhe 1988 139
- Chan, C. 1988 “Optimal Synthesis of Finger Follower Automobile Cam Systems” U. Cal. Berkeley 215
- Colombo, T. et al 1990 “Computer Simulation of the Dynamic Behaviour of the Overhead Camshaft Valve Train Assembly with Hydraulic Lash Adjuster” Paper 905174, Proc. 23rd FISITA Conf. Turin May 1990
- Daniel, K. 1980 “Hydraulischer Ventilspielausgleich Aufbau, Funktion, Entwicklungsgrundlage” Motortechnische Zeitschrift 41 12
- EATON CORPORATION 1979 “Engine designer's guide to hydraulic valve lash compensation” 2nd 1979
- Hanachi, S Freudenstein F. 1986 “The Development of a Prediction Model for the Optimization of High-Speed Cam-Follower Systems with Coulomb Damping, Internal Friction and Elastic and Fluidic Elements” ASME J. of Mechanisms, Tran., and Aut. in Design 108 506 515
- Hatch, C.T. Pisano A.P. 1989 “Modelling, Simulation, and Modal Analysis of a Hydraulic Valve Lifter with Oil Compressibility Effects” Working Paper U. Cal. Berkeley 1989
- Heywood, J. 1988 “Internal Combustion Engine Fundamentals” Mc Graw-Hill New York 930
- Kaiser, H.-J. Phlips P. Schamel A. 1989 “Engine Noise Reduction by Camshaft Modifications in Multi-Valve Engines” 2nd Aachen Colloquium Automobile and Engine Technology October 1989
- Kreuter, P. Maas G. 1987 “Influence of Hydraulic Valve Lash Adjusters on the Dynamic Behaviour of Valve Trains” SAE Technical Paper 870086
- Lacy, D.J. 1987 “Computers in analysis techniques for reciprocating engine design” Proc. I. Mech, Eng., Int. Conf. Computers in Engine Technology Cambridge 24-26 March 1987 55 68
- Miyamura, N. Nagano S. 1985 “Hydraulic Lash Adjuster” JSAE Review 1985 28 35
- Phlips, P.J. Schamel A.R. Meyer J. 1989 “An Efficient Model for Valvetrain and Spring Dynamics” SAE Technical Paper 890619
- Reitz, J. Mäthner M. 1983 “Entwicklung eines Tassenstöels mit hydraulischem Ventilausgleich” Motortechnische Zeitschrift 44 293 297
- Siegel, E. 1984 “Der hydraulische Ventilspielausgleich der neuen Opel-Motoren” Motortechnische Zeitschrift 45 217 220