GB138183A - Improvements in valve gear for internal combustion engines - Google Patents

Abstract

138,183. Scott, A. Feb. 24, 1919. Valves; valve-gear. - In a, four-stroke-cycle engine, separate piston valves f, g, for inlet, and exhaust of a group of four cylinders firing in succession, are operated by fluid pressure, the four inlet valves being worked by compressed air, and the four exhaust. valves opened by the pres. sure of the working fluid in their respective cylinders and closed by compressed air. Each valve comprises a pair of connected pistons y, z, Fig. 8, and a flat slide t free to move radially with respect to the valve, but moving axially with it, and working with friction against one or other face of a recess s, Fig. 3. The slides t protect the valves f, g from the explosion and give the frictional resistance necessary for the correct working of the valves. Each valve chamber is provided at each end with an inlet and an exhaust port such as k', k<2> for the actuating-fluid. Each working piston p, Fig. 4, contains a chamber p' which is placed alternately in communication with an air reservoir by ports r, n, and with pipes leading to the valve chambers by ports r, m. The ports m of the cylinder A' are connected to the inlet valve chambers of cylinders A<3>, A<4>, and to the exhaust valve chamber of cylinder A<4> the ports m of the cylinders A<2>, A', A<4> axe connected similarly to the valve chambers in cyclic order; and a piston-controlled port o in each working cylinder is connected to the exhaust valve chamber of the same cylinder. The cylinders fire in the order A<1>, A<2>, A<3>, A'. In operation, each exhaust valve is opened by pressure from the same working cylinder; the piston of cylinder A', soon after the commencement of its exhaust stroke, distributes compressed air to close the inlet valve of cylinder A', and to open the inlet valve and to close the exhaust valve of cylinder A<4>. The ports r in the piston register with the ports m leading to the valve chambers four times in each cycle, but on one occasion the air escapes from the open exhaust of one of the inlet valve chambers, and on two occasions there is no pressure in the chamber p<1>. The distribution of compressed air by the other pistons is similar.