Patent GB-574554-A (GB)
Title: Improvements in or relating to internal combustion engines
IPC: F02K7/02
Filed: 1943-08-11
Abstract: 574,554. Generating combustion products under pressure. HALLOWELL, E. Aug. 11, 1943, No. 12944. [Class 51 (i)] [Also in Group XXIX] In an apparatus for generating gases for driving turbines or the propulsion of air or other craft of the kind in which fuel is burnt in a conduit having a constriction to produce oscillatory gas columns operating in a manner analogous to pistons in effecting, scavenging, charging and compressing operations, separate means are provided for supplying and igniting a highly explosive fuel rich in oxygen, -e.g. a mixture of petrol and ethyl nitrate to initiate the cycle or to facilitate the combustion of the normal fuel so as to produce gaseous columns having a velocity not less than the speed of sound in the gas. As shown, the combustion conduit 11, surrounded in part by a cooling jacket 17 and terminating in a convergentdivergent outlet 18, is enclosed in an outer casing 19, the annular chamber 20 thus formed being divided by an apertured partition 27 into chambers 26, 28 supplied respectively with air and fuel under procure. The fuel supply means comprise separate jets 31, 33 for the normal and special starting fuels, both supplies being controlled by a valve 30 which is operated by a piston 34 subject to the pressure in the chamber 28 so that, as the pressure in this chamber rises, the supply of ordinary fuel increases with simultaneous reduction in the supply of starting fuel. A duct 37, fitted with a non-return valve 38 supplies compressed air to the chamber 26 for use during starting. The air and fuel from the chambers 26, 28 enters the conduit 11 through a series of valves 12 each comprising, as shown in Fig. 2, a perforated ring 14 split longitudinally and normally held by internal tension with its perforated parts in contact with the imperforate portions of the valve seat 13; on rise of pressure in the chambers 26, 28 the valves open and air and fuel pass to the conduit 11 through apertures 15. Cooling ribs 16 are provided between the valve seats 13. The outer casing 19 is formed with air inlets fitted with scoops 23 and controlled by valves 21 similar to the valves 12, these valves opening, during the depression phases in the casing 19, to admit air which, during the alternating pressure phases, is compressed and discharged'through a valve 22 into the air chamber 26. An ignition plug 39 for firing the initial charge is arranged near the constriction 18 while a second and independent plug 40 for normal operation is provided in the closed end of the conduit 11. The operation of the latter plug is controlled by a diaphragm 44 subject on its inner side to the pressure in the conduit 11 and on its outer side, through duct 47 to the pressure in the fuel chamber 28, the movement of the diaphragm actuating a contact-maker 43 in the circuit which includes an interrupter coil 45 the delaying action of which may be adjusted by a variable rheostat 46. The outer casing 19 terminates in a convergent-divergent jet 24 which, when the apparatus is used for operating a prime mover such as an impulse turbine exhausting into a pressure turbine, may be omitted or the constriction may be reduced and an equivalent constriction imposed on the gas flow through the pressure turbine.