Patent GB-427266-A (GB)
Title: Improvements in the method of and means for supercharging internal combustion engines
IPC: F02B25/00
Filed: 1933-11-24
Abstract: 427,266. Two-stroke engines. H. B. MOTOR CORPORATION, 18, Fairview Avenue, Port Washington, Long Island, New York, U.S.A.-(Assignees of Harper, W. ; 18, Fairview Avenue, Port Washington, Long Island, New York, U.S.A.) Nov. 24, 1933, No. 32888. Convention date, Dec. 8, 1932. [Classes 7 (ii), 7 (iv), and 7 (vi)] [See also Groups XXVI and XXXIV] Charge, supplying and regulating ; valves.-A charge of air or combustible mixture is delivered to the crank case and is there acted on by combustion products released from the cylinder at some pressure to raise the pressure of the charge in the crank case and force it into the cylinder. As shown a six-cylinder engine is constructed with three separate crank chambers 43, each pertaining to a pair of coaxial cylinders. A two stage fan 53, Figs. 4 and 5 supplies air to two carburetters, the mixture flowing by two pipes 57 to two manifolds 63 sideby-side. Further subdivision of the supply piping leads to two inlet ports 32, Fig. 6, for each crank chamber, ports 42 in crank discs 37 controlling admission. Each cylinder has main exhaust ports 16, inlet ports 12 with transfer passage 13 for admission of charge from the crank chamber through the piston port 15, and two escape ports 18, Figs. 6 and 7, leading to ducts 20 formed in removable piping 19. All the cylinder ports are controlled by a piston head, escape ports opening first ; with the pistons at inner dead centre the ports 42 admit charge from the fan 53 to a crank chamber. During the power stroke this charge is compressed by the conjoint action of the two pistons, which towards the end of these strokes allow gases at high pressure to flow out of the ports 18 into the ducts 20 ; the gases pass by pipes 21 to pairs of inlets 101 on opposite sides of baffle plates 100 in a chamber 91, this being tortuous in shape and connected by openings 99 to the top of the crank chamber. There is a separate chamber such as 91 for each crank chamber. The gases at high pressure acting on the charge within the crank chamber forces it into the two cylinders displacing the combustion products of the previous cycle. As the gases in the piping 21, 20 are still at some pressure there is a surge back of products into the cylinder through the ports 18 ; these gases flow against the new charge and tend to drive it away from the main exhaust ports 16, the piston top being shaped to direct the gases from the ports 18 into the desired path. After the cylinder ports are closed by the piston on its compression stroke a rotary valve 96 allows the gases to escape from the chamber 91, while a new charge enters the crank chamber from the fan. The pressure at which the gases enter the chamber 91 is limited by relief valves 23, Fig. 7. The degree to which the gases may act on the new charge is controllable by a shutter 114 placed on the openings 99 ; the shutter is moved by a handle which also controls the carburetter throttles the latter not being affected until the shutters are closed. If it is desired to dispense with the action of the gases on the new charge the chamber 91, valve 96, shutter 114 &c., can be removed and closed vessels 143, Fig. 11 are placed on top of each cylinder ; gases under pressure now simply surge into and out of the cylinders and the vessels 143. Cylinders, ports and baffles of, and arrangement of igniters in.-The preliminary exhaust ports 18, Fig. 7, are formed in the pipes 19 which are tangential to the sides of the cylinders. The piston heads are formed with the recesses 112, 112<1>, which act as deflectors for guiding gases returning from the pipes 19 out through the main exhaust ports 16. There are two sparking plugs 168, 169, to each cylinder the lower one being placed with its igniting points in a chamber 176. Crank chambers.-The central crank web is in the form of a disc to reduce the compression space with the chamber. Igniting in.-Each cylinder has two sparking plugs of differing characteristics. The upper one 168, Fig. 13, is selected for rapid heat dissipating properties and may have a small mica insulator 170 ; the other plug 169 is chosen for good insulation properties and may have a porcelain insulator 172. The four plugs pertaining to two cylinders are connected to divided secondary windings 182, 183 in the manner shown, the centres of the part windings being earthed. Centrifugal fans.-The two stage fan comprises the two casing parts 69, 70 separated by an annular flange 72 central with the rotor plate 74, which carries on its two faces the impeller blades 85. On the low pressure side these blades are straight but on the second stage the inner ends are curved as shown at 89, Fig. 4. Fixed guide vanes 86 87 are provided to direct the flow of the gases. The inlet 71 has a gauze cover 88. The edges of the flange 72 and plate 74 are bevelled outwardly towards the delivery side. Lubricators.-The lubricator for the pistons passes through bores 150, 151, Fig. 6, in bolts 149, whose position is adjustable to vary the point at which the cross bores 150 enters the small well receiving the oil. Each piston has a deflector 154 which causes the fresh charge of combustible to flow during its movement towards the small end of the connecting rod and thereby direct oil in the charge on to this part.