GB739821A - Improvements in two-stroke engine supercharger drives - Google Patents

Abstract

739,821. Centrifugal compressors. AKTIEBOLAGET GOTAVERKEN. Jan. 12, 1954 [Jan. 13, 1953; Dec. 17, 1953], No. 930/54. Class 110 (1). [Also in Group XXVII] A scavenging and charging compressor 12, Fig. 1, is driven by an exhaust gas turbine 9 through a slip coupling 17 and a free-wheel clutch 4 or 5 in series between an engine shaft 1 and the compressor shaft 11, the coupling 17 being arranged at low speed to reduce the compressor speed relatively to the speed mechanically transferred from the engine. Two bevel pinions 2, 3, which are coupled to the engine shaft 1 through the oppositely-acting freewheels 4, 5, respectively, engage a bevel gear 6 upon a shaft 8, the latter thereby having a unidirectional rotation irrespective of the direction of engine operation. Shaft 8 drives another shaft 19 through a splined coupling 20, with double universal joints, for example, to provide for both relative axial movement and a degree of misalignment between the shafts 8 and 19; shaft 19, which drives a further shaft 16 through bevel gear 18, is connected by the slip coupling 17, such as a hydraulic or electromagnetic coupling, and a rigid coupling 15 to the shaft 11. The turbine may be started independently of the engine by a hydraulic motor 21 geared thereto or by directing compressed air, for example, on to the turbine blades from a nozzle 22; electric or pneumatic means may alternatively be used and the auxiliary driving means may be connected to the compressed unit by a releasable or free-wheel coupling, not shown. In a modification, the two free-wheels are replaced by gearing which enables the shaft 19 to have a undiirectional rotation whilst a freewheel is arranged in one of the bevel gears 18. The degree of slip of coupling 17 is selected so that the compressor speed is the lowest possible to provide complete scavenging when the engine is on no load. In another modification, the crankshafts 32, 33, Fig. 4, of the opposed pistons 31 are interconnected by gears 34-38 whilst on the oppositely rotating stub shafts 39, 40 of gears 36 and 37 respectively, are freewheels 43, 44 having toothed rims 45, 46 in engagement with a shaft 48, thereby ensuring a unidirectional drive of the latter. The shaft 48 is provided with two universal joints 49, 50 and a hydraulic, pneumatic or electromagnetic slip-coupling 51, the outupt shaft 53 being joined to an exhaust-driven turbine which actuates a charging and scavenging compressor, not shown. The coupling 51 embodies an overload arrangement 52 preferably comprising a friction clutch loaded to a predetermined amount by springs 54. Auxiliary apparatus such as pumps for the fuel, lubricant and hydraulic couplings not shown, may be driven from the unidirectional part of the apparatus.