Published version 2003-01-1798.pdf (1.72 MB)

A comparison of the flow fields generated for spark and controlled auto-ignition

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conference contribution
posted on 20.08.2014 by Graham Pitcher, James W.G. Turner, Graham Wigley, Rui Chen
Valve timing strategies aimed at producing internal exhaust gas re-circulation in a conventional spark ignition, SI, engine have recently demonstrated the ability to initiate controlled auto-ignition, CAI. Essentially the exhaust valves close early, to trap a quantity of hot exhaust gases in-cylinder, and the fresh air-fuel charge is induced late into the cylinder and then mixing takes place. As a logical first step to understanding the fluid mechanics, the effects of the standard and modified valve timings on the in-cylinder flow fields under motored conditions were investigated. Laser Doppler anemometry has been applied to an optical engine that replicates the engine geometry and different valve cam timings. The cycle averaged time history mean and RMS velocity profiles for the axial and radial velocity components in three axial planes were measured throughout the inlet and compression stroke. The turbulent mixing for the two cases are described in terms of the flow field maps of the velocity vectors, vorticity and turbulence kinetic energy and the integrated tumble ratio as a function of crankangle.

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Aeronautical and Automotive Engineering

Published in

SAE Technical Papers

Citation

PITCHER, G. ... (et al.), 2003. A comparison of the flow fields generated for spark and controlled auto-ignition. Presented at: 2003 JSAE/SAE International Spring Fuels and Lubricants Meeting, Yokohama, Japan, 19-22 June.

Publisher

© Society of Automotive Engineers of Japan

Version

VoR (Version of Record)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/.

Publication date

2003

Book series

JSAE Paper;20030223

Language

en

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