Characterization of the Reversal Discharge Coefficient of Intake Port and Direct Discharge Coefficient of Exhaust Port of an Engine Used in Formula SAE Prototype

In the present work it was studied the flow around the intake and discharge valves of the HONDA CBR 600RR Engine, used in Formula SAE by the team of CEFET-MG, Formula Cefast.

Presenting the methodology and experimental results in the measurement of the reversal discharge coefficient of the intake port and the discharge coefficient of exhaust valve of the engine used in the prototype, serving as a starting point for further studies and development of the prototype drive system. These experimental tests were performed on the flow bench infrastructure of the Pontificia Universidade Católica de Minas Gerais, PUC-MG, using the engine head, same model as used in the Formula Cefast team prototype. Necessary parts and adaptations for tests were developed, such as a mechanism for opening and closing the valves during the experiment. Measurements were taken to define the actual mass flow rate of air through the valves for valve lifts, ranging from 0 mm to 7.3 mm for the exhaust valve and from 0 mm to 8.2 mm for the intake valve. The study was performed by opening only one valve. Increment between valve lift measurements was 0.2 mm and 03 measurements were made for each valve lift. From the measurements of the pressure difference before and after the valves and the air temperature it was possible to determine the theoretical mass flow as a function of the valve lift. The ratio between the actual mass flow rate and the theoretical mass flow rate, characterized the discharge coefficient of the flow. The methodology applied in the experiment was effective with a behavior of discharge coefficients as a function of valve lift comparable with other works and theoretical reviews, ranging from 0.45 to 0.91 for the exhaust valve and ranging from 0.42 to 0.69 for the intake valve.