Investigation of iVVT Timing and Lift Effects on a Gasoline Spark Ignited IC Engine Performance Using Detailed Numerical Simulation

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Tabatabaei, Touraj | 2013

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 45323 (08)
University: Sharif University of Technology
Department: Mechanical Engineering
Advisor(s): Hosseini, Vahid; Saidi, Mohammad Hassan
Abstract:
One strategy for increasing efficiency and decreasing brake specific fuel consumption in spark ignition engines is using variable valve timing mechanism which is proportional to engine speed and load. Variable timing refers to the opening and closing time of inlet and outlet valves and their duration and overlap. In conventional SI engines the performance of valves is designed on a fixed point at special engine load and speed. While investigations show that if performance time of valves is changed according to engine load and speed, performance parameters of engine will improve.
In reviewing articles related to variable valve timing, their effect was considered on volumetric efficiency. In this project, we first investigate on the effect of valve opening on turbulence parameters like turbulence mean velocity, integral and length turbulence scales and etc. Then a mass burning turbulent model which considers these effects is used. A multi-zone thermodynamic model for combustion process is developed .At last we calculate performance parameters at different working conditions by varying time of valves performance
Keywords:
Multi-Zone Method ; Spark-Ignition Internal Combustion Engines ; Variable Valuee Timing