GB569270A - Improvements in power plants - Google Patents

Abstract

569,270. Combustion - product plant. AKTIEBOLAGET GOTAVERKEN. Nov. 9, 1943, Nos. 18623 and 18624. Convention dates, Nov. 9, 1942. [Class 7 (i)] [Also in Group XXVI] The plant comprises an internal-combustion two-stroke engine 1, a turbine 3 driven by exhaust gases from the engine supplied. at two different pressures at different times, and a compressor 2 driven by the turbine, which produces scavenging, and maybe supercharging, air for the engine. The gases are admitted to the turbine at different stages. The lowpressure gas pipe 23 (or 40) is alternately open to a low-pressure stage of the turbine, or a pipe 15 leading to the atmosphere. Scavenging air from the compressor passes through a pipe 5 and ports 6 in the engine cylinder. Lowpressure exhaust gases for the turbine are controlled by a valve 8 actuated by a cam or other shaft 13. Gases discharged through ports 16 and channel 17 leading to a conduit 18, are higher in pressure than the final pressure in the cylinder. A valve 19 controls this gas flow. For multi-cylinder engines, the turbine and compressor are common to all the cylinders. Turbine blades of the impulse type are preferably provided for the high-pressure stages, and reaction blades for the remainder. The impulse blades may rotate at a higher speed as by arranging them on the same blade wheel as the reaction blading, but at a greater radius. To facilitate starting of the engine, the lowpressure gases are passed to atmosphere either by manual or automatic means. Fig. 1 shows a valve 24 held closed by gas pressure from the conduit 18 acting through a pipe 25 on a piston 27. When the pressure in 18 is low, a spring forces the piston downwards and, through links 30, 31, the valve 24 drops to close the pipe 23. A silencer may be fitted to the pipe 15. The valve 19 is opened before the piston 4 uncovers the ports 16, and closes as the valve 8 begins to open. Two valves 8 may be provided, opening one after another. The engine may have two pistons running in opposite directions. The. engine may -be reversible with adjusting devices for the valves. The ports 16 may be replaced by a single, valve-controlled port. The turbine 3 may be supplied with a set of starting nozzles fed with compressed air or steam, and a compressor started up by an electric motor which may operate in parallel with the compressor driven by exhaust gases. In Fig. 3, the cylinder 1 is arranged for double or transverse flow scavenging. Scavenging and super-charging air enters a port 33 and exhaust gases are delivered through a single conduit 35. The gases pass to either of two branches 40, 41, high-pressure gases passing through 41, and low-pressure gases through 40 to the lowpressure stage of the turbine 3. The valve 37 alternately closes conduits 40, 41. It may be a slide valve. Exhaust gases may be used to impel separate turbine wheels on a common, or separate,' shafts. A Root's blower may be used in place of the compressor 2.