GB565150A - Improvements in or relating to internal-combustion engines - Google Patents

Abstract

565,150. Two-stroke engines. REYNOLDS, J. A. E. March 24, 1943, No. 4819. [Class 7 (ii)] In a compression-ignition or other engine comprising two coaxial cylinders 10, each with opposed pistons 21, 22, each piston of one cylinder being directly coupled to the corresponding piston of the other and to a crankshaft 12, situated between the cylinders, by means of a Scotch yoke 23 the members 24 of the yoke 23 form slides for a cross-head embracing the centre crank-pin and comprising blocks 27 each engaging the crank-pin over slightly less than half its-circumference, so that each is free to tilt slightly. Each piston comprises a crown 33 integral with a shank 34 on which is secured a skirt 35 retained bv a nut 38, a gasket 39 of mica or other material of low thermal conductivity being interposed between the crown and skirt. The crown and shank may be of heat-resisting ferrous material, with heat-dissipating fins within the crown and on the shank, and the skirt of a light alloy. The yoke 23 is connected to each of the pistons 21 by a connecting-rod 40 entering the hollow shank 34 and engaging a transverse gudgeon 41 therein, the gudgeon being parallel to the crankshaft axis and allowing a slight tilting movement of the piston relative to the yoke. Lubricating grooves and passages 28 are provided. The outer pistons 22 are similar to the pistons 21 and have cooling fins 46 under the crown and on the shank. They preferably have a stroke of two-thirds that of the pistons 21 and are connected by levers 43 and rods 29 supported in guides 30 and carrying yokes 31 to engage cross-heads 32 on the two outer crank-pins. The engine cylinders 10 are provided with piston-controlled exhaust ports 18, and-inlet ports 20 supplied with air by a double-acting pump 52 having an air-inlet filter 53 at each end and driven through gears 59 from the crank-shaft 12. Fuel injectors 50 are supplied from a fuel-pump 49. In a modification, each inner piston 21 has its skirt integral with the crown and with a stem of H-section or double-H section to facilitate cooling: A modification of the yoke 23 is described in which each of the distance-pieces 25 is provided with a, pin engaged by a tilting pad sliding on a guide rail in order to take up side loads.