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Title: The effect of cylinder de-activation on thermo-friction characteristics of the connecting rod bearing in the New European Drive Cycle (NEDC)
Authors: Mohammadpour, Mahdi
Rahmani, Ramin
Rahnejat, Homer
Issue Date: 2014
Publisher: © SAE International
Citation: MOHAMMADPOUR, M., RAHMANI, R. and RAHNEJAT, H., 2014. The effect of cylinder de-activation on thermo-friction characteristics of the connecting rod bearing in the New European Drive Cycle (NEDC). In: 8th International Styrian Noise, Vibration & Harshness Congress: The European Automotive Noise Conference, Graz, Austria, SAE Technical Series: 2014-01-2089, 7pp.
Abstract: The over-riding objective in modern engine development is fuel efficiency. This has led to a host of pursued measures, including down-sizing (a lower number of cylinders), high output power-to-weight ratio, variable valve activation or cylinder de-activation (CDA) as well as a gradual trend towards mild or micro-hybrid technology. Furthermore, The main aim is to combine a suitable combination of the aforementioned methods with various driving conditions in order to reduce thermal and frictional losses as well as meeting the ever stringent emission directives as outlined in the NEDC. Another imperative is to ensure good NVH refinement which can be adversely affected by application of the above trends, such as light weight constructions and exacerbated power torque variations with CDA. The highlighted issues affect all the load bearing conjunctions in an engine. In particular, increased load fluctuations with CDA can also affect the whirl stability of big-end bearings. Therefore, the current paper concentrates on the issues that affect the big-end bearing thermo-frictional characteristics and dynamic stability in NEDC cycle. The predictive approach, which is critical in a multi-variate problem of this kind, includes determination of regime of lubrication under fluctuating loads and rictional characteristics contributed by both elastohydrodynamics of the bearing overlay as well as boundary friction as the result of asperity interactions. Predictive results include applied dynamics, contact kinematics, frictional power loss, maximum lubricant temperature and minimum film thickness variations during the NEDC. The difference between the CDA mode and the normal mode (all active cylinders). These show that the general benefits accrued through fuel efficiency do not necessarily conform to improved big end bearing frictional efficiency.
Description: Copyright © SAE International. This paper is posted on this site with permission from SAE International. It may not be shared, downloaded, duplicated, printed or transmitted in any manner, or stored on any additional repositories or retrieval system without prior written permission from SAE. This paper was presented at the 8th International Styrian Noise, Vibration & Harshness Congress: The European Automotive Noise Conference. http://papers.sae.org/2014-01-2089/
Version: Accepted for publication
DOI: 10.4271/2014-01-2089
URI: https://dspace.lboro.ac.uk/2134/14270
Publisher Link: http://papers.sae.org/2014-01-2089/
Appears in Collections:Conference Papers and Contributions (Mechanical, Electrical and Manufacturing Engineering)

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