GB889509A - Improvements in or relating to a free piston engine - Google Patents

Abstract

889,509. Free piston compressors and gas generators. BURION, E. P. Dec. 17, 1958 [Dec. 20, 1957], No. 40756/58. Classes 7(1) and 7(2). A free piston engine comprises two similar movable assemblies displaceable in opposition and each including two motor pistons associated with a compressor piston which is provided with at least one jacket delimiting a cylinder for a fixed piston, the fixed piston serving to enclose a charge of gas in the cylinder to thus form a power accumulator in which the gas is compressed during a driving stroke so that the movable assemblies are brought towards each other after the driving stroke which latter occurs during combustion in two parallel motor cylinders enclosing the motor pistons of the two movable assemblies. As shown the two cylinders 5 and 6 communicate with each other at their middle part via a chamber 11 into which an injector 12 injects. Injection by the injectors 13, 14 occurs primarily and injection into the chamber 11 by the injector 12 occurs later. The injector 12 may be omitted. The fuel pump may be worked off the synchronizing mechanism. A by-pass from the fuel pump cylinder may be regulated according to the compression pressure of the engine. The left hand piston assembly comprises two driving pistons 35, 36 and a compressor piston 37. The piston 37 comprises cushion cylinders 38, 39. The right hand piston assembly is similar to the left hand assembly. The pistons 35, 36a may be slightly longer than the pistons 36, 35a so that the scavenging ports 7, 7a are slightly closed before the closing of the exhaust ports 8, 8a. The scavenging ports may be nearer the piston than the exhaust ports. The pistons 35 and 36a can be of slightly different lengths to improve scavenging in the chamber 11. The cushion pistons may be mounted as shown in Fig. 1 or rigidly mounted (Fig. 5). In Fig. 5 the interior of the pistons is air-cooled. The amount of return power of the cushion cylinders may be varied by known means. As shown in Fig. 3, the synchronizing mechanism may comprise a rack 48 which is integral with the cushion cylinder 39. Alternatively the synchronizing mechanism may comprise a system of connecting rods and cranks.