GB893312A - Improvements in or relating to multi-unit arrangements for four-stroke rotary pistonengines - Google Patents

Abstract

893,312. Rotary piston engines. N.S.U. MOTORENWERKE A.G. Oct. 6, 1959 [Oct. 7, 1958], No. 33817/59. Class 110 (2). A two-unit four-stroke rotary piston engine, in which each unit comprises a stationary housing the inner peripheral wall of which is formed as a number of curves meeting in lobes, a rotor having a number, one more than the number of said curves, of apices in continuous sliding contact with the said inner peripheral wall, the rotor rotating on a crank-pin or eccentric of a shaft journalled centrally on the housing, at a speed different from the shaft, and inlet and exhaust ports, controlled by the rotor, in the walls of the housing, is characterized by the two units being so combined that the contours of the two peripheral walls and the two sets of inlet and exhaust ports are in axial alignment, whilst the two sets of crankpins and rotors thereon are displaced by an angle of 180 degrees. Fig. 1 shows diagrammatically two units with a common crank-shaft 4, the housings 1 having two lobes and the rotors 7, 8 each having three apices. The rotors rotate planet-wise about the centres 9, 10 of crank-pins on the shaft 4 which rotates on a fixed axis 3, an internal toothed gear on each rotor meshing with a stationary gear on the end wall of each housing. The gear ratio produces three revolutions of the shaft 4 for each revolution of the rotor. The inlet ports 12, exhaust ports 13 and lobes are in axial alignment, but the rotors are relatively displaced through 180 degrees to produce an ignition every half revolution. Two such units may be coupled with the housing contours and ports in axial alignment and the two crank-shafts displaced relatively by 180 degrees, in which case a dynamic balance results and ignition occurs every half revolution in two cylinders simultaneously; or the two crankshafts are displaced by 90 degrees to produce an ignition every quarter-revolution but it is then necessary to restore dynamic balance by counterweights. Alternatively, the crank-shafts are relatively displaced by 90 degrees, the housing contours and ports of the two units also being displaced by a right-angle, in which case balance is achieved but independent inlet and exhaust manifolds are required for the two units. Fig. 7 shows a two-unit engine with two working chambers 23, 24 separated by a wall 22 having inlet channels and ports for the two units. The rotors 77, 78 rotate on eccentrics 55, 56 which are connected by projecting sleeves 55<SP>1</SP>, 56<SP>1</SP>, a screwed inner sleeve 80 and a bolt 85. A shaft 83 is splined into the eccentric 56, and the sleeve 55<SP>1</SP> is journalled in a bearing 14 carried by the wall 22. The exhaust ports 13 in the aligned contours of the peripheral walls, and the inlet ports, are also axially aligned. Oil ducts convey oil into the apex portions of the rotors to act as a circulating coolant. Internal gears 25 in the rotors mesh with stationary gears 26, and balance weights 87, 88 are provided. The wall member 22 may be made in two parts, one part containing the inlet ports and passages. The two parts have mating curved surfaces which pass approximately diametrically through the axis of rotation, the two parts being bolted together to form a working whole. Coolant passages are provided in the end and central walls. Specifications 791,689 and 892,476 are referred to.