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Application of an Integrated Valvetrain and Hydraulic Model to Characterization and Retuning of Exhaust Valve Behavior with a DPF
ISSN: 0148-7191, e-ISSN: 2688-3627
Published April 14, 2008 by SAE International in United States
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There exists a strong interaction between the engine cylinder, intake and exhaust gas flow dynamics and the dynamics of mechanical and hydraulic components constituting the valvetrain system, which controls the engine gas flow. Technologies such as turbo-charging and Diesel particulate filtration (DPF) can significantly increase port gas pressure forces acting on the exhaust valve. When such systems are introduced or undergo design modifications, the operation of valvetrain system can be greatly affected and even compromised, which in turn may lead to degradation of performance of the internal combustion engine. Often, the valvetrain system needs to be retuned. Further, predictive analysis of design issues or evaluation of design changes requires highly coupled simulations, combining models of gas pressure forces and the dynamics of all mechanical and hydro-mechanical parts constituting the valvetrain.
This paper presents the application of an integrated numerical model to the study and alleviation of undesired phenomena observed in experimentally measured exhaust valve lift in a 4-cylinder, mid-size Diesel engine, during testing with a Diesel particulate filter. The valve is driven by a finger-follower mechanism with a hydraulic lash adjuster post. The phenomena occurred near the closing segment of the lift across the operating speed range and were thought to be related to the features in the cam design profile as well as to the exhaust port backpressure caused by the DPF cycling and/or aging.
First, the coupled dynamic model of a single exhaust valvetrain (rigid camshaft segment, cam lobe, finger follower, hydraulic post, poppet valve) was employed to obtain a verification and physical explanation to the observed exhaust lift features. Once a satisfactory agreement between experimental and simulation results was reached, the model was further exercised in search of solutions that would eliminate the observed exhaust valve lift behavior while preserving the essential elements of the original valvetrain design. Several such design changes were identified and their contributions to a reduction of undesired lift phenomena were investigated.
CitationOkarmus, M., Keribar, R., Oliva, M., and Tonin, N., "Application of an Integrated Valvetrain and Hydraulic Model to Characterization and Retuning of Exhaust Valve Behavior with a DPF," SAE Technical Paper 2008-01-0292, 2008, https://doi.org/10.4271/2008-01-0292.
Modeling of SI and Diesel Engines, 2008
Number: SP-2156; Published: 2008-04-14
Number: SP-2156; Published: 2008-04-14
- Frizoni, P. Dark, M. “GT-VTRAIN Analysis of a Direct-Acting and a Roller Finger-Follower Valve Train” 2004 GTI User Conference Paper
- Morel, T. Keribar, R. Leonard, A. “Virtual Engine/Power train/Vehicle Simulation Tool Solves Complex Interacting System Issues” SAE Paper 2003-01-0372 2003
- Keribar, R. “A Valvetrain Design Analysis Tool with Multiple Functionality” SAE Paper 2000-01-0562
- Gamma Technologies Inc. “GT-VTRAIN User's Manual” 2004
- Okarmus, M. Keribar, R. Ham, R. “Integrated Hydro-mechanical Simulation of a Cam-Rocker-Unit Injector System to Address Noise and Vibration Issues” SAE Paper 2006-01-0887 2006
- Lin, Y. Ramachandra, P. Tanaka, Y. “Valve Train Dynamic Analysis and Validation” SAE Paper 2004-01-1457
- Philips, P. Schamel, A. “The Dynamics of Valvetrains With Hydraulic Lash Adjusters and the Interaction with the Gas Exchange Process” SAE Paper 910071
- Zou, D. McCormick, H. “Dynamic Model and Computer Simulation of Valve Train Assemblies with Hydraulic Lash Adjuster” SAE Paper 960351
- Tong, K. Zhao, Y. Lu, J. “Determination of Aeration of Oil in High-Pressure Chamber of Hydraulic Lash Adjuster in Valve Train” SAE Paper 1999-01-0646
- Porot, P. Trapy, J. “A Numerical and Experimental Study of the Effect of Aeration of Oil on Valve Trains Equipped With Hydraulic Lash Adjusters” SAE Paper 930997
- Kreuter, P. Maas, G. “Influence of Hydraulic Valve Lash Adjusters on the Dynamic Behavior of Valve Trains” SAE Paper 870086
- Krueger, K. Engelhardt, T. Ginzinger, L. Ulbrich, H. “Dynamical Analysis of Hydraulic Chain Tensioners - Experiment and Simulation” SAE Paper 2007-01-1461
- Totten, G. Dekker M. “Handbook of Hydraulic Fluid Technology” 2000
- Peterson, M. Winer, W. “Wear Control Handbook” ASME 1980