GB682174A - Improvements in or relating to internal combustion engines for propelling pedal bicycles - Google Patents

Abstract

682,174. Cylinders; spray-carburetters. TEEGEN, H., and LOHMANN-WERKE AKT.-GES. Aug. 8, 1950 [May 5, 1949], No. 12000/49. Classes 7 (ii) and 7 (iii) [Also in Group XXXI] In a pedal bicycle fitted with a self-igniting twostroke internal combustion engine having means, such as a carburetter 14, Fig. 1, for admitting fuel/air mixture to the crankcase 17, and means in the form of a cylinder liner 3 for varying the compression ratio, there is provided gearing, such as a friction, chain, belt or shaft drive for connecting the engine to the rear bicycle wheel; the moving parts of the engine within the crankcase may serve to atomize the fuel/air mixture which on its way to the combustion chamber 5 passes along the piston 12 thereby being reheated and also cooling the piston. A Bowden cable 9 around a threaded spindle 7 enables the latter to be rotated in either direction by a lever fitted on or near the handlebars of a bicycle (see also Group XXXI), in order to effect movement of the cylinder liner 3, which is prevented from rotating by a screw 11, and so cause a change in the volume of the combustion chamber 5. Fuel/air mixture from the carburetter 14 is compressed in the crankcase 17 and led by semi-circular transfer passages in the liner 3 into the combustion chamber 5, the shape of the pas; sages being such as to produce loop scavenging of the cylinder. The piston 12, which need not incorporate piston rings, has a hard skin that may be formed by a layer of chromium, for example. In a modification, the variation in the volumes of the combustion chamber 5 is effected by a cam mechanism and the engine may incorporate a fuel vaporizer or a fuel and air control valve. In the latter case the fuel which may be a mixture of low-grade petrol and lubricating oil is atomized in the crankcase by action of the moving parts therein, the crankcase having a serrated, surface to further assist the atomization. The fuel and air control valve comprises a body 33, Fig. 11, a fuel nozzle 34 and a manually-operated slide 35 which carries a needle 36 that extends centrally in an axial bore in the slide and fits within the nozzle, the latter being located in the axial bore of the slide 35 which is provided with an air inlet bore 35a so. that by moving the slide the quantity and strength of the fuel/air mixture can be regulate. The engine may have more than one cylinder but its total capacity will not usually exceed 100 cc. although the preferred embodiment has one cylinder and a capacity of less than 30 c.c. The engine preferably drives the bicycle through reduction gearing, not shown.