A Study of Air Flow in an Engine Cylinder

A &etroke-cycle test engine was equipped m“th a glass cylinder an-d the air rnocements within it were studied wht% the engine was being motored. Dij$erent typee of air @w were produced by ueing shrouded intake valves in various arrangements and by altering the 8hape of the intake4r pawage in the qdinder head. The air movement8 were made visible by miz-ingfeather8 with the entering air, and high-epeed motion p“cture8 were taken of them 80 that the air current~ might be dudied in detail and their velocitie8 measured. Motion pictures were also taken of ga801ine 8praya injected into the cylinder on the intake 8troh-e. The photograph 8howed that: A wide varidy of induced air mocement8 could be created in the cylinder; the movements alway8 perw”sted throughout the compre8tion 8troke; and M.e only type of morement that persisted until the end of the q.tcli wa8 rotation about the cylinder axi8. The velocities of the air eurrent8 were approxz”mately proportional to the en~”ne 8peed and had about the 8ame value whether the jlow wa8 orderly or turbulent. Orderly air movement8 greatly aided the distm”bution of the 8pray8 about the cylinder.