GB1202125A - A rotary internal combustion engine - Google Patents

Abstract

1,202,125. Rotary internal combustion engines; gas turbine plant. R. SCHMIDT. May 8, 1968 [May 9, 1967; April 2, 1968], No.21892/68. Headings F1F. and F1G. A rotary I.C. engine comprises first and second intermeshing helically threaded screws 1, 2, Fig. 1 received with clearance in overlapping cylindrical bores in a housing 4. The treads on one screw are convex profile, lying mainly outside the pitch circle and the threads of the other screw concave lying mainly inside the pitch circle. Synchronizing gears 7, 8 ensure running of the screws without contacting each other. Combustion material, which may be pulverized coal, coal-water emulsion or hydrogen, the latter ensuring clean non-toxic exhaust gases, is admitted together with combustion air through an inlet port 20, Fig. 2, into chambers between the screws and housing which move axially along the screws at increasing volume. The fuel is ignited at locations 17, 18 after closure of each chamber by a thread of the screws by beams from lasers 11, 12 or alternatively by an electric arc 27, Fig. 2 or by conventionial sparking-plugs. With the chambers still increasing in volume the expanding gases of combustion drive the screws. Internal cooling of the engine may be carried out before or after ignition preferably by liquid which can also be used as a sealant. The engine 41, Fig.4, may be included in a plant which includes a compressor 34 driven from the shaft 38 and a turbine 44 which drives by way of a shaft 46 a generator G. Air and fuel are admitted to the compressor through conduit 31, 32 respectively, the fuel being substantially constant for idling purposes. The compressed mixture then passes to the engine 41 and by way of an ignition device 37 and /or fuel supply conduit 36 through which fuel supply is controlled to give isothermel expansion, a combustion phase is initiated in the engine chambers. The gases of combustion are used to drive the compressor 34 and charge an accumulator 42 which supplies the turbine 44. Liquid coolant 54 passes to the engine through a control device 55 controlled electrically or mechanically by a device 51 influenced by the pressure and temperature in the accumulator 42 through sensors 48, 49 and the temperature of the turbine exhaust gases by a sensor 50, so that the coolant is condensed in the turbine 44 and recycled through a line 53. The compressor 34 and engine 41 may be relieved to a considerable extent of axial thrust by opposite arrangement of the high-pressure ports 35, 40. The compressor 34 and turbine 44 may both be of intermeshing screw type. In another arrangement, to operate on the Ericsson cycle, an approximation of isothermal compression is achieved with an internal cooling of the compressor 34, Fig.5, and a constant pressure between the compressed cold medium and the expanded hot medium by a heat exchanger 57. With efficiency of heat exchangers being 90% at most, the temperature of the inlet port 40 never reaches the temperature at the exhaust port 39 and to mitigate against this, combustion is controlled by the amount of fuel and/or the size and arrangement of the openings of the fuel supply conduits 36 taking into account the reaction speed of the fuel so that after ignition the temperature drop in the heat exchanger is compensated for to effect the desired isothermal expansion.