GB1464956A - Internal combustion engine - Google Patents

Abstract

1464956 Opposed piston type IC engines L E KRAMER 22 March 1974 [30 March 1973] 12871/74 Heading F1B The invention relates to an I.C. engine of the kind having a pair of opposed pistons mounted in a cylinder, the pistons moving apart after firing of the charge which has been compressed between the pistons; towards the end of the power stroke, exhaust ports are opened, then a scavenge air port is opened to discharge the exhaust gases through the exhaust ports, then finally a fuel/air mixture inlet port is opened, the pistons now moving inwardly to compress the charge ready for the next power stroke. The engine shown comprises two cylinders 48, 54 in which are disposed pairs of opposed pistons 42, 66 and 51, 58, the pistons being connected by rods to the crankpins of a pair of crankshafts 29, 31. Each piston is formed with a head portion such as 45 of piston 42 and a compressor portion such as 46 of piston 42. As the pistons 42, 66 move away from each other following firing of the charge which has been compressed therebetween, the piston portion 45 first uncovers the exhaust ports 74, 76; then the piston portion 67 uncovers the scavenge air inlet ports 77 and air which has been compressed by the compressor portion 56 of the piston 51 in the space 81 discharges through duct 88 and the inlet ports 77 to scavenge the exhaust gases through the exhaust ports 74, 76. As the pistons 42, 66 continue to move away from each other the piston portion 67 then opens the air/ fuel mixture inlet ports 78 through which mixture which has been compressed by portion 62 of the piston 58 in space 91 now discharges through duct 96 and ports 78. The pistons 42, 66 now start to move towards each other closing the ports 78, 77 and 74, 76 and compressing the mixture charge therebetween for the next power stroke. As the pistons 42, 66 move away from each other air is drawn in through a non-return inlet valve into the space 101 defined by compressor portion 46 of piston 42, and air/fuel mixture is drawn in through a non-return inlet valve into the space 109 defined by the compressor portion 111 of piston 66. As the pistons 42, 66 move towards each other so the air is compressed in space 101 and subsequently discharged through duct 104 and inlet ports 106 as scavenge air for scavenging exhaust gases from the cylinder 54. Similarly the air/fuel mixture is compressed in space 109 and subsequently discharged through duct 112 and inlet ports 113 as a fresh charge for the cylinder 54. The pistons 51, 58 in the cylinder 54 operate similarly but in the opposite phase.