GB578436A - Improvements in internal-combustion engines of the free-piston type - Google Patents

Abstract

578,436. Two-stroke engines. MUNTZ & CO., Ltd., A., and FARMER, H. O. March 2, 1942, No. 2759. [Class 7 (ii)] [Also in Group XXVIII] In a compression-ignition engine of the freepiston type, a fuel-injection pump is operated, or one of the limits of its delivery period is timed, by an oscillatory inertia member connected to the primary moving parts of the engine; energy is stored in the inertia member during the first part of the stroke of the moving parts and the inertia member is afterwards retarded, and its kinetic energy is transmitted to means for operating or timing the pump. As shown in Figs. 1 and 2, a two-stroke freepiston air compressor comprises opposed pistons 26, 29. in a power cylinder 20 having inlet and exhaust ports 21, 22; the inlet ports communicate with a scavenging-air receiver formed by the casing 23. The piston 26 is connected by a rod 27 to a piston 28 in a double-acting aircompressor cylinder 24 discharging at 50 into the receiver 23 and at 48 to a receiver (not shown). The piston 29 is connected to a cushioning piston 31 in the cylinder 25. For synchronizing, crossheads 36, 37 are maintained horizontal by arms 38, 39 sliding in guides 40, 41 and are connected by limbs 34, 35, 42, 43 to levers 32, 33 oscillating about a common axis. A fuel-injection nozzle 44 is supplied from a pump 45, Fig. 6, actuated by an arm 53 on the pivot shaft 52 of the synchronizing lever 33. An inertia lever 54, pivoted at 55 to the arm 53, has an eye 56 movable about the shaft 52 and is weighted at 57. The tappet 58 actuating the fuel pump 45 is connected by links 59 to the inertia lever, so as to follow the vertical component of displacement of the midpoint of the lever, the movement of which is checked by a laminated buffer spring 62 fixed on the arm 53 and engaged by a pin 63 on the lever when the latter nears one end of its displacement. Similar buffer springs mounted on the casing _co-operate with lugs on the links 59. In the opposite direction the lever is checked by a hydraulic dashpot having an element 64 mounted on the arm 53 and the other element 65 having a pin-and-slot connection 66 with the lever. Kinetic energy is stored in the lever 54 during acceleration of the arm 53 and subsequently given up to the pump plunger, as indicated by a graph, Fig. 8 (not shown). The invention may be similarly applied to a timing device for determining the begining or end or both of the fuel-injection period in a free-piston engine having a pump actuated by other means, for example by a small gas engine energized by working fluid compressed in the engine combustion chamber, as described in Specification 536,671, [Group XXVIII].