Patent GB-977468-A (GB)
Title: Improvements relating to internal combustion engines and methods of operating them
IPC: F02B3/06
Filed: 1961-04-14
Abstract: 977,468. I.C. engine combustion chambers. F. STUMPFIG. April 14, 1961 [April 14, 1960], No. 13529/61. Heading F1B. An engine comprises a cylinder b, Fig. 1, and a piston arranged so that a part of the air in the cylinder space is compressed in an evaporation chamber d and another substantial part is compressed in an air compression space h communicating with the evaporation chamber, arranged so that fuel vapour formed before ignition is urged towards an ignition location i Fig. 2, in the evaporation chamber and shortly before ignition the access of pure air to the ignition location is prevented whilst subsequently to ignition, burning mixture principally in a narrow high speed stream is ejected over the main fuel concentration in the evaporation chamber out into the air compression space. During the suction stroke, pure air is sucked into the cylinder through an inlet valve e in the direction of arrows I while a fuel-air mixture formed in a carburetter o is sucked through a conduit z and the guide member f into the evaporation chamber d in direction of arrows II, III towards an opening m. Fuel droplets contained in the mixture are centrifuged out against the heated wall of the evaporation chamber. A rib i may be provided to assist evaporation. During the compression stroke, compression of air partly in space h and partly in the evaporation chamber d causes transverse eddying of the fuel mixture in the direction of arrow IV whilst the piston effects closure of the opening M along length A-B only, thus allowing concentration of the fuel vapour in the vicinity of the sparking plug l. After ignition the fire stream blows out at the ends of the evaporation chamber d into space h whilst completing evaporation of the remaining fuel and effecting mixing with the air present in the space h. In a modification the piston may be shaped to produce a highly compressed cushion of air beneath the exhaust valve g which forces most of the burning mixture to be ejected out at the inlet valve end of the evaporation chamber d. In a further modification the evaporation chamber has a rectangular tube-shaped crosssection at its central part and is formed from an upper and lower part. In another embodiment having a sidemounted evaporation chamber d Fig. 5, fuel is forced in the direction of arrow V Fig. 7, into a fuel injection device p for storage in a space s therein between successive openings of the inlet valve e. During the suction period air moving in the direction of the arrows I and II passes partly through a channel q to assist ejection of fuel present in a connected mixture tube r into the air stream. The air inlet port and passage are positioned so that the air flow inside and outside the cylinder has the same direction when seen in plan view. In a further embodiment, an evaporation chamber d Fig. 8, is open towards the cylinder axis and initial ignition takes place in the spark plug sleeve W. The spark plug may be positioned centrally or at one end of the evaporation chamber and the spark plug sleeve may be enlarged to serve as the evaporation chamber. In a two-stroke cycle embodiment fuel is fed to a storage chamber s Fig. 11, either by pump or from a float chamber, which in the piston position shown communicates with an evaporation chamber d by means of an inclined tube g, surrounded by a space J which is in communication with a space K and a duct M. During upward piston movement, crankcase suction is communicated by means of a piston slot L, to duct M and thence to spaces J and K to draw fuel into the storage space S. During downward piston movement, crankcase pressure is communicated in the same way to inject fuel into the evaporation chamber d. In a modification, the space J does not communicate with space K but is connected to the upper cylinder space through a narrow bore N and space K communicates with atmosphere through a bore P. A check valve is arranged in the fuel line to a float chamber and in the upper piston position a piston aperture T communicates with space J and tube G. Air drawn in through bore P mixes with the fuel in storage chamber s. In a further modification, an extended auxiliary space J, Fig. 14, opens into the cylinder space above the scavenge port D and a further narrow air admission port into the space J may be provided for air admixture with the fuel in tube G. A piston groove R may be provided which in the upper piston position coincides with the tube G to allow compressed air from the space J to prevent deposit of fuel on the piston. The engine may be operated on the four-stroke cycle or be arranged with scavenge blowers, with laterally arranged valves or with slide valves. Reference has been directed by the Comptroller to Specification 919,210.