GB1471533A - Internal combustion engines and their operation - Google Patents

Abstract

1471533 Rotary valve IC engines EXXON RESEARCH & ENG CO 24 May 1974 [24 May 1973] 24823/73 Heading F1B An I.C. engine comprises a piston and cylinder, a system to supply air/fuel mixture to the cylinder, means to ignite the mixture and means to exhaust the combusted products and supply means for an oxygen-containing gas operative to provide said gas at a pressure which is no greater than either (a) the maximum possible pressure of air/fuel charge in the cylinder before ignition of the charge or (b) a pressure, in atmospheres, at least equal to the volumetric compression ratio of the engine, comprising a chamber of fixed volume arranged to receive oxygen containing gas during part of the cycle, to confine the gas and to establish communication between the interior of the chamber and the interior of the cylinder initially at a point of the compression stroke which is substantially at the moment of ignition or when the pressure in the chamber is substantially equal to the pressure in the cylinder. Valve spool 36 is rotatably mounted between upper and lower parts 35 and 33 of the valve housing, and includes, in addition to an inlet duct 46 and an exhaust duct 48, a chamber 50 which communicates with the peripheral surface of the valve spool by a passage 51. The spool rotates clockwise as seen in Fig. 3. A compressed air duct 54 leads to a port 55 which communicates with passage 51 during the time taken for the spool to rotate through 20 degrees. Passage 51 is offset, in the axial direction of the spool, from the inlet and exhaust ducts. Operation. At the moment when ignition occurs, spool 36 has turned to a position where passage 51 communicates with port 52, so that the burning air/fuel mixture in the cylinder compresses the air in chamber 50 to cylinder pressure. As the pressure falls during the expansion stroke, the burning mixture is diluted with air which ensures complete combustion. The exhaust port 49 and passage 51 communicate simultaneously with port 52 so that chamber 50 is vented. An additional vent, opposite port 55 and connected to a low-pressure zone may be provided to completely vent chamber 50. In a 4-cylinder in-line engine the spools are gear-driven from the crankshaft, adjacent spools rotating in opposite directions. The compressed air is provided by a singlestage reciprocating piston pump, providing air at about 10 atmospheres and with an output of about 15% by volume of the swept volume of the engine.