Patent GB-154640-A (GB)
Title: An improved multiple expansion internal combustion engine
IPC: F02B41/06
Filed: 1919-05-26
Abstract: 154,640. Sperry, E. A. May 26, 1919. Values; valve-gear; regulating.-In a compound engine, the low-pressure cylinder, which may be closed at one end to form a charging-pump, is associated with one or a pair of explosion cylinders to which is supplied air under pressure. The charges may be ignited by the heat of compression or by an electrically-heated wire, fuel being injected into the combustion space during approximately one-half of each working stroke. The pressure of the air admitted to the combustion cylinders may be 100 lb. per sq. in., and the volume of the low-pressure cylinder may vary from 2¢ to 10 times that of the highpressure cylinder. According to the construction shown in Fig. 2, two combustion cylinders 1, 2 expand their gases into a low-pressure cylinder 3 in which the cushioning-pressure is equal to the pressure of the entering charge. Scavenging- air is admitted to the high-pressure cylinders through valves 145 actuated by face-cams 146 on an auxiliary shaft 33. The valves 145 are opened towards the end of each compression stroke, the air trapped in the chambers 148 behind the valves being admitted to the cylinders for scavenging purposes towards the ends of the exhaust strokes. Air for the working charges is compressed in the lower end of the central cylinder 3, the clearance in which is adjusted by a piston 70 actuated by hand or automatically by an electric motor 81 in accordance with the speed of the engine. Compressed air is admitted to the combustion cylinders during the suction strokes through a valve 34 arranged concentrically with a transfer valve 25 between a high-pressure and the low-pressure cylinder. A modified construction is described having combustion chambers of semi-spherical shape in which are located concentric air-admission and transfer valves inclined to the axes of the cylinders. A further modification is described, in which separate airadmission and transfer valves are used, a pair of air-admission valves being located on one side of an inlet passage 24 and a transfer valve on the opposite side. The air-admission valve 34, Fig. 3. seats upon the transfer valve 25 and carries a piston 38, a sleeve 57 on the air valve sliding over a stationary depending head 52 and a piston 56 secured to the transfer valve. A spring 39 bears upon the piston 38 to hold the valve 34 to its seat. Compressed air supplied through a pipe 27<1> may be used alone or in conjunction with the spring 39 for the same purpose. The air supply for a combustion cylinder is delivered to a chamber 45 which discharges through passages 48, 49 to cool the transfer valve, the interior of which may contain a volatile cooling-medium such as mercury. A passage 61 places the space above the piston 56 in open communication with the combustion cylinder to prevent the pressure of the air in the chamber 45 from lifting the valve 34. Cooling-water may be circulated through the valve casing by pipes 55, 53. The valve 25 is opened by a cam-actuated lever 29, Fig. 9, thevalve 34 being raised by a second cam-actuated lever 41 which engages the underside of the piston or the collar 38. The levers 29, 41 are connected by a link 43 which holds the valve 25 closed when the valve 34 is open. In a modified construction of co-axial air-admission and transfer valves, the inner valve seats upon the outer valve and controls the compressed-air supply which enters the stem of the outer valve controlling the transfer passage between the cylinders. The outer valve has radial fins adjacent its seat. A further modified construction is described in which the air-admission and transfer valves are arranged independently, the transfer valve carrying a balancing-piston and having cooling-ribs on its face. The guide for the stem of the transfer valve also has cooling-fins. Air entering the cylinders passes over the face of the transfer valve. The low-pressure cylinder, according to one construction, contains a pair of exhaust valves, the stems of which are each engaged by bell-crank levers connected together by a link. One of the bell-crank levers is acted upon by a cam on the shaft 33. Fig. 11 shows a liquidfuel injector to a valve 151 in which fuel is supplied by a pump (not shown). The fuel is conveyed through a passage 152 to a chamber 153 discharging through a passage 154 to a recess in a seating 157 for a cam-actuated needle-valve 158. From the recess, the fuel passes with a whirling motion to an internal chamber 155. Ascending through passages 256, the fuel fills the interior of the valve casing, some of it escaping through an overflow valve 159. The fuel enters the cylinder with a whirling motion when the valve 158 is opened by a tappet 104 carried by a shaft 105 rocked by a lever (not shown) oscillated by a cam 89, Fig. 7, on the shaft 33. The cam is mounted on a sleeve having an inclined slot 97, in which engages a pin carried by an inner sleeve 92. A hand-lever 93 is connected to the sleeve 92, and a second hand-lever 93<1> to the sleeve 90. By moving the handle 93, the sleeve 90 is slid axially with the sleeve 92 without relative movement thereto. Movement of the hand-lever 93<1> angularly adjusts the sleeve 90 upon the sleeve 92. The first movement controls the fuel-admission period, and the second movement the moment at which the fuel injection commences.