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http://dx.doi.org/10.15435/JILASSKR.2013.18.2.100

A Numerical Study on the In-cylinder Flow and Fuel Distribution with the Change of Intake Valve Lift in a GDI Engine  

Kim, K.B. (국민대학교 자동차공학 전문대학원)
Song, M.J. (국민대학교 자동차공학과)
Kim, K.S. (국민대학교 자동차공학과)
Kang, S.H. (국민대학교 자동차공학과)
Lee, Y.H. (국민대학교 자동차공학과)
Lee, S.W. (인천대학교 기계시스템공학부)
Publication Information
Journal of ILASS-Korea / v.18, no.2, 2013 , pp. 100-105 More about this Journal
Abstract
While variable valve actuation or variable valve lift (VVL) is used increasingly in spark ignition (SI) engines to improve the volumetric efficiency or to reduce the pumping losses, it is necessary to understand the impact of variable valve lift and timing on the in-cylinder gas motions and mixing processes. In this paper, characteristics of the in-cylinder flow and fuel distribution for various valve lifts (4, 6, 8, 10 mm) were simulated in a GDI engine. It is expected that the investigation will be helpful in understanding and improving GDI combustion when a VVL system is used. The CFD results showed that a increased valve lift could significantly enhance the mixture and in-cylinder tumble motion because of the accelerated air flow. Also, it can be found that the fuel distribution is more affected by earlier injection (during intake process) than that of later injection (end of compression). These may contribute to an improvement in the air-fuel mixing but also to an optimization of intake and exhaust system.
Keywords
Computational fluid dynamics; Fuel vapor distribution; Intake flow; Valve lift;
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