GB517958A - - Google Patents

Abstract

517,958. Valves; cylinder ports. SMITH, H. Oct. 14, 1938, No. 29781. [Classes 7 (ii) and 7 (vi)] In. a two-stroke engine, air-admission ports 10 and exhaust ports 11 controlled by the piston are further controlled respectively by a pair of oscillating ring valves 3 and 4 surrounding the cylinder and each of right-angled section. Fig. 1 shows the left half of the cylinder with the piston descending ' and 'the exhaust valve 4 opened, exhaust taking place through all the cylinder ports 10 and 11 into the manifold 9 The exhaust valve 4 is closed later and the inlet valve, 3 opened as shown in Fig. 2, which represents the right half of the cylinder, with the piston ascending. Scavenging-air is thus admitted from the manifold 8 through the ports 10 and sweeps the remaining gases through the ports 11 and upwards into the exhaust manifold 9 through transfer ports (not shown) provided in the horizontal portions of each of the rightangled valves 3 and 4, these ports being controlled by a hand-adjusted throttle segment 5. The piston then closes the exhaust ports 11, and supercharging occurs through the inlet ports 10. The two end air ports 10 at each side of the cylinder are inclined, as shown, away from the eyhaust ports to prevent loss of charging-air. The valves 3 and 4 may be split and sprung on to the cylinder, or may be in segments bolted together.