The influence of different in-cylinder flows on combustion in an SI engine.
Published: 2005
Language: eng
Number of pages: 176
Description: The main contributions of this study are: (i) the novel data analysis techniques for evaluating CWT energy and finding the interactions between the flame image data and cylinder pressure data; and (ii) the intake shroud system to generate the different intake flows.The main objective of this study is to determine the influence of different in-cylinder flow fields on combustion in a spark ignition ( SI) engine. Towards this goal, measurements were conducted to study how different in-cylinder flows, generated by different orientations of a shrouded intake valve, influence the combustion process in an SI engine through: (i) stand alone motored velocity measurements, (ii) simultaneous fired pressure-flame propagation image measurements, and (iii) steady flow measurements for four different intake flows. Novel data processing techniques were applied to the in-cylinder velocity data, the flame image data and the steady flow data to extract more information on the influence of different in-cylinder flows on combustion. A continuous wavelet transformation ( CWT) was introduced to overcome the limitations of the traditional velocity reduction methods by representing both time and scale information in a plane. Because of the drawbacks of the fiber optic instrumented spark plug (FOSP), flame image-pressure data are simultaneously measured and evaluated to characterize the interactions between the flame propagation and mass burn rates. Steady flow results from a flowbench are also compared with early flame kernel development (EFKD) results from the flame image data.Results taken from a single cylinder V6 optical engine are reported. Wavelet analysis is appropriate for analyzing the flow fields in combustion engines because it gives information about the transient events in a time and frequency plane. The mass burn duration and peak cylinder pressure, evaluated from the cylinder pressure data under fired conditions for all four flow cases, show good correlation (the correlation coefficient is higher than 0.75) with the flame kernel growth rate Sg calculated from the flame image data. The velocity energy distributions were represented by CWT average contour plots with respect to a variety of scales and crank angle degrees in a time-frequency plane.
Notes: Source: Dissertation Abstracts International, Volume: 66-10, Section: B, page: 5648.

Thesis (Ph.D.)--University of Toronto, 2005.

Electronic version licensed for access by U. of T. users.