GB559273A - Improvements in internal-combustion-operated free-piston air-compressors - Google Patents

Abstract

559,273. Free-piston compressors. PESCARA, R. P. Sept. 3, 1942, No. 12482. Convention date, Sept. 3, 1941. [Class 8 (i)] [Also in Groups XXVI and XXVII] An internal-combustion free-piston compressor comprises a main compression chamber 6<SP>1</SP> and an auxiliary chamber 6<SP>2</SP> for compressing air to supply the motor cylinder and a blower 19 supercharging both chambers. The blower may be driven by a turbine utilizing the motor exhaust, the supply of which is controlled by the pressure of the main receiver 16 acting on a valve 22 ; a valve-controlled atmospheric exhaust is also provided. The receiver pressure also controls the output of the fuel pump 13 which supplies fuel injector 18. The motor cylinder contains pistons connected to synchronize and respectively operating the compressor piston 5 and a piston 8 subject to the return pressure of a cushion 9 ; this cushion is connectable to atmosphere or to receiver 16, or closed to both, by a valve 35, subject to the cushion pressure through a pipe 44 and to the pressure in the scavenger casing 7 through an aperture 45. In a modified apparatus, the blower 19 supplies only the auxiliary chamber, while the main compression chamber is supercharged by the exhaust from a turbine driven by air from the receiver 16. The mean pressure in the closed circuit so formed is regulated by a slide valve connecting the circuit either with atmosphere or with a compressed air reservoir. The valve 35 in this modification is controlled on the one hand by the cushion pressure, and on the other hand by a cam reciprocated in accordance with the scavenge chamber pressure and the pressure of receiver 16 applied in opposite directions.