Intake valve flow characteristics of production cylinder heads
Date
2001
Authors
Simpson, Trenity Scott
Major Professor
Advisor
Van Gerpen, Jon
Committee Member
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Abstract
Most general internal combustion engine books that discuss discharge coefficients of engine intake valves refer to work that is not representative of typical intake valve discharge coefficients. These commonly referenced works were found to have collected flow data using an ideal experimental setup. The main goal of this study was to clearly illustrate that intake valve discharge coefficient results obtained from ideal experimental setups are not representative of discharge coefficient results found from flow tests on typical production cylinder heads. This goal was achieved through a thorough literature search and through rigorous flow tests performed on two production cylinder heads. A summary of methods utilized in the literature to process valve flow data was included and considerable variation was found. Comparisons were made between the data collected for this study and data found in the literature. The influence of flow regimes on the discharge coefficient results was illustrated and discussed.
The influence of the variation of pressure drop across an intake valve and the variation of Reynolds Number on the valve discharge coefficient was also addressed. It was found that the response of the valve at low lifts and high lifts was similar to that of a converging nozzle and a sharp-edged orifice, respectively. Finally, the discrepancies between the discharge coefficient trends observed with ideal experimental setups and production cylinder heads was illustrated. The discrepancies were found to be the result of a shift in the valve lifts at which flow regime transitions occurred, and in some cases a reduction in their influence on the discharge coefficient variation with valve lift. A recommendation was made for how typical intake valve flow should be represented when being discussed in general internal combustion engine literature.
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thesis