GB438019A - Improvements in or relating to two stroke cycle internal combustion engines - Google Patents

Abstract

438,019. Two-stroke engines; pumps; regulating. HOWARD, F. A., 183, Stiles Street, Elizabeth, New Jersey, U.S.A. Feb. 1, 1934, No. 36. Convention date, Aug. 4, 1933. [A Specification was laid open to inspection under Sect. 91 of the Acts, July 4, 1934.] [Classes 7 (ii), 7(iv), and 7 (vi)] A two-stroke-cycle engine is provided (1) with a rotary blower which delivers scavenging, cooling and charging air through ports in the cylinder wall, and (2) with a reciprocating compressor which delivers carburetted air to the cylinder during the compression stroke, both the compressor and the blower being driven from the crank-shaft. In the construction shown in Fig. 1, the compressor piston 198 is driven from an eccentric 200, which is adjustably secured to a driving flange 206 on the crank-shaft 201. Mixture is admitted to the compressor from a carburetter 219 alter traversing passages 218, 215 and an inlet valve formed by a flat spring or reed 216 disposed in a recess in the cylinder head 209. After the working piston 184 has closed air inlet ports 182, mixture conveyed through passages 207, 193, located between exhaust ports 183 and past a valve 189 is admitted to the combustion chamber 185 where it is ignited by a sparking plug 186. The combustion chamber is offset and is constructed as a crescent shape dome. The air blower is of the gyratory type in which a drum 223, Fig. 3, actuated by an eccentric 236 carries a vane 230 guided in a rocking member 224. The blower draws in air through a port 237 and delivers it through ports 227 to inlet ports 182 in the engine cylinder and a valve 238 is provided to control the amount of air byepassed over the vane to the suction side of the blower. Supercharging in the engine cylinder may be increased by a valve 241 which may be controlled to increase the back pressure of the exhaust gases. During idling, the valves 241, 238 are opened and the compressor 198 supplies a fuel-air mixture which is less rich than that supplied during normal running. As the valve 238 is closed the fuel-air ratio of the carburetter is proportionately increased, and the valve 241 is only loaded after the valve 238 has been closed. At high and low speeds the air delivered by the blower 223 may effect internal cooling of the engine cylinder while at medium speeds it effects supercharging. In the ten cylinder radial engine shown in Fig. 4, an impeller 273 on the crank-shaft 255 draws mixture from a carburetter 278 through an exhaust-heated chamber 280 and supplies it to a ten cylinder radial compresser having cylinders aligned with the engine cylinders. The air is supplied by twin rotary blowers 311 set at 180‹ and provided with counterweights 314. The blowers deliver into an annular passage 303 which supplies the air inlet ports 182. A vane 316 on one of the blower-drums carries a rod 321 which drives an accessory shaft 323 and may actuate the electrical ignition apparatus. An oscillating cylinder lubricating pump 286 and a current generator 294 are carried on the front end of the crank-shaft whilst the rear end carries a clutch 326 of the kind described in Specification 435,990. The clutch acts as a flywheel. In the control system shown in Fig. 8, opening movement of the rod 346 first opens the throttle valve 357 of the carburetter. To prevent the engine racing at low throttle openings when unloaded, a governor 374 moves a link 348 to reduce the opening movement of the rod 346. Further movement of the rod 346 closes the byepass valve 307 in the rotary air pump while a cam 353 simultaneously opens the fuel valve 354. A lost-motion connection in a link 364 prevents operation of the valve 345 in the exhaust pipe until the valve 307 is closed. Further movement of the rod 346 then causes a bell-crank lever 366 to compress a spring 371 and close the valve 345. At high engine speeds the governor 374 relieves the back pressure on the exhaust system until a spring 368 returns the valve 345 to its open position. To effect additional cooling, water may be supplied to the cylinder simultaneously with the carburetted air and the water valve is controlled by the linkage described. If water is used, the exhaustheated chamber 280 is insulated from the exhaust pipe.