GB138524A - Improved valve gear applicable to internal combustion engines working on four-strokecycle and comprising four cylinders - Google Patents

Abstract

138,524. Lepersonne, O. May 14, 1919. Valves; valve-gear.-In a four-cylinder four-strokecycle engine, inlet and exhaust are controlled by concentric cylindrical slide valves arranged in a single valve chamber common to the. four cylinders. The valves are of the type in which the distribution for each cylinder is controlled by an outer valve member such as g and an inner valve member such as k; in order to simplify the valve-operating mechanism, the various inner and outer valve members having similar movements are connected together so that the whole of the valve members may be operated from two or from three half-speed eccentrics or cranks. To ensure the same timing in each cylinder, the valve-actuating mechanism is arranged so as to avoid variations due to obliquity of the connecting-rods of the gear. In the arrangement shown, there are three valves, (1) the valve g, i, h comprising the outer valve members for cylinders I, IV, (2) the valve k, j, l comprising the outer valve members for cylinders II, III and the inner members for cylinders I, IV, and (3) the valve mm. comprising the inner members for cylinders II, III. The three valves are worked from separate eccentrics or cranks p by linkages such as r, u, x, such that the movements of the valves corresponding to the upper and lower halves zvx and xyz of the valve crank-pin circle are similar. The inlet passages to the valve-chest are at b, c and the exhaust passages d, e, f. In a modification, the passages d, f are dispensed with and the valve m is extended in both directions, the exhaust from cylinders I, IV, as well as that from cylinders II, III, passing through the interior of the valve to the passage e. In these arrangements, each cylinder port a is opened for exhaust and closed at the end of the admission period by an outer valve member such as g, and the end of the exhaust period and the commencement of admission are determined by the movement of an inner valve member such as k. In another modification, the gear is worked from two half-speed eccentrics or cranks, and only two valves are used, one comprising the outer valve members for cylinders I, IV and the inner member for cylinders II, III, and the other comprising the inner members for cylinders I, IV and the outer members for cylinders II, III. In this arrangement., the exhaust is closed slightly before dead-centre and the admission opened slightly after dead-centre by the outer member, which is then moving slowly: the arrangements previously described with three valves permit of a later closing for exhaust and earlier opening for inlet, and give greater efficiency.