GB1179891A - Improvements in or relating to Gas Generators - Google Patents

Abstract

1,179,891. Free piston gas generators. VSESOJUZNY NAUCHNO-ISSLEDOVATELSKY INSTITUT ZHELEZNODOROZHNOGO TRANSPORTA. Feb. 14, 1967, No.7028/67. Heading F1Q. In a free piston gas generator wherein at least one pair of oppositely acting free pistons 5 have small diameter ends slidable in a central diesel engine cylinder 1 and large diameter ends continuously subjected to the pressure of gas in buffer spaces 3 for the return stroke, the scavenging air is compressed in the annular spaces 2 between the small and large piston ends and the spaces communicate through passages 8 with auxiliary chambers 9 containing pistons 10 movable automatically to vary the effective volume of the compression chamber so as to maintain the piston strokes constant. The pressure of the gas in the buffer spaces 3 is also automatically controlled to maintain the stroke constant. If the fuel supply to the generator is increased the stroke of each piston 5 also increases, whereby the amplitude of rotary oscillation of a synchronizing cam-shaft 6 driven by racks 7 movable with the pistons 5, Fig. 2 (not shown) similarly increases. The increased angle of turn of the cam-shaft 6 causes cams 36, 37 thereon to intermittently open pilot valves 31, 32 to thus direct air from a bottle 38 to the respective chambers 23, 29 of distributer valves 19, 25. Pressurization of the chamber 23 causes movement of a spring-loaded spool 20 to a position which supplies hydraulic fluid to the chamber 16 of an hydraulic cylinder 14 containing a piston 13 connected by a rod 12 to the auxiliary pistons 10 which thereby move to decrease the volume of the auxiliary chambers. The pressurizationof the chamber 29 connects the buffer chambers 3 to an annular gas receiver 4 receiving the air compressed by the pistons and supplying scavenging air to the engine cylinder 1. When the fuel supply is decreased the pilot valves 31, 32 do not open and air in the chambers 23, 29 bleeds away through orifices 24, 30. If the fuel supply, and thus the load, is at a minimum the pistons 10 uncover ports 11 to connect the auxiliary chambers to atmosphere.