Patent GB-579021-A (GB)
Title: Improvements in or relating to supercharging systems for internal combustion engines
IPC: F02B39/08
Filed: 1944-08-24
Abstract: 579,021. Pumps; regulating. AKTIEBOLAGET LJUNGSTROMS ANGTURBIN. Aug. 24, 1944, No. 16139. Convention date, Aug. 19, 1943. [Classes 7 (ii), 7 (iii) and 7 (vi)] [Also in Group XXVI] A charging arrangement comprises a rotary positive-displacement compressor 32 which is driven by an exhaust-actuated turbine 24 and which delivers air to a dynamic compressor, preferably a centrifugal blower 54, which is directly driven by the engine. The compressor 32 is driven from the turbine through a multi-speed gear, a two-speed gear being shown. This comprises bevel gears 82, 98 and clutches 92, 106, either of which can be engaged by fluid under pressure supplied through pipes 112, 116 and controlled by valves 114, 118. The centrifugal blower 54 is driven from the main shaft 16 of the engine through a stepup gear and a hydraulic coupling 62. The gear comprises a planet carrier 66 keyed to the engine shaft, planets 68 engaging a stationary ring gear 64, and planets 70 engaging a sun gear 72 keyed to the driving member of the coupling. Liquid for actuating the coupling is supplied by a pipe 74 containing a control valve 76. Four compressors 32, Fig. 2, which are arranged radially and are supplied with air by scoops 30, comprise spirally grooved rotors 36, 38, and have inlets and outlets at opposite ends, the outlets 42 leading through inter-coolers 44 and pipes 48 containing interconnected throttle valves 148 to the centrifugal blower 54. Excess power from the turbine is absorbed by a step-down feed-back gear which comprises a sun gear 122, Fig. 3, keyed to the turbine shaft and meshing with pinions 124 on a carrier 126. The pinions 124 mesh with a ring gear 128 which is connected through a freewheel clutch having rollers 132 with a part 134 extending from the planet carrier 66 keyed to the engine shaft. Exhaust gas is collected from the cylinders by a manifold ring 20 having a waste-gate valve for controlling the supply to the turbine, and a waste air valve 140 controlled by a barometric bellows 142 is also provided to regulate the pressure of the charge. Rocket propulsion is effected by directing both the air and exhaust gas vent pipes rearwardly. The carrier 66 may be utilised for driving engine auxiliaries, e.g., by a gear wheel 146. Assuming an aircraft is starting from ground level, the sequence of operations is first to disconnect the centrifugal blower 54 and use the compressors 32 only, the exhaust waste valve and the air waste valve 140 being gradually closed and opened respectively. At an altitude of about 10,000 feet the drive of the several compressors 32 is changed in succession from low speed to high speed. At an altitude of about 20,000 feet the centrifugal blower 54 is brought into operation, though for cruising at this height this may not be necessary except after the critical altitude has been reached. The fuel is supplied by a carburetter, direct to the cylinders, or by nozzles 156 arranged in the casing of the centrifugal blower, the rotor in this case being kept rotating by a free wheel clutch 158 when the blower is not in use.