GB568753A - - Google Patents

Abstract

568,753. Two stroke engines. CASTELLlNI, A. P., and ROBEY & CO., Ltd. July 14, 1943, No. 11446. [Classes 7 (ii) and 7 (vi)] A two-stroke internal-combustion engine has air or mixture compressed in the crank-case and then transferred to the combustion space by valves which are mounted together with their operating gear in the piston-head and are actuated through the swinging movement of the connecting rod on the gudgeon pin. As applied to a V-engine with cylinders arranged at 45 degrees, Fig. 1, each cylinder casting 1 is fitted with a head 3, cooled by water jackets 6 and having an exhaust port 5 and fuel inlet 4. The crank-case is fitted with air inlet valves 11, operated against closing springs 17 by cams 13 on a shaft 13a driven from the crank - shaft. The air supply may, as shown, be increased by means of a supercharger 25, connected by passages 26 to the air valve chamber 26a. If light fuel is used, the supercharger induces its air through a carburetter or mixture may be induced by piston suction. The free space within the crank-case may be reduced by the provision of boxes 27 secured concentrically to the crankshaft and arranged to embrace the crank-webs. The air compressed in the crank-case is admitted to the combustion space through piston-head poppet-valves 31, 31a closed by springs 31b. The valves are actuated by rockers 35 mounted on pins 36 and operated by a roller 40a, Fig. 3, on a cam 40 on a shaft 41. The cam has a portion 44 urged by a spring into contact with a fixed abutment on the connecting rod. During the swing of the connecting rod to the right, Fig. 1, the roller 40a can yield until it has passed over the part 39, but on the return movement to the left the valve 31 is opened. The valve 31a is simultaneously operated by similar mechanism. The fuel pump 51 is driven from a shaft 52 geared to the crankshaft which also operates the exhaust valve cam-shaft 53. Lubrication of the piston is effected from the crank-shaft duct 65 leading through passages 66-68 to the bearing liners 69a and thence through passages 70, 71 to the small end and cylinder walls. To reduce contamination of the air from oil spray, the crankpins have throwing collars 80 which direct oil to a plunger pump operating in the manner described in Specification 568,784. The timing, both for the combustion chamber valves and the crank-case valves, is described in the Specification. In place of compression ignition, the charge may be spark ignited. Different timings of the valves 31 may be obtained by the use of interchangeable cam-shafts 41 with different settings. In addition to V and in-line engines, the invention may be applied to radial engines, the crank-case inlet valves being dispensed with and air or mixture supplied by a supercharger.