GB272002A - Improvements in two-stroke double acting internal combustion engines - Google Patents

Abstract

272,002. McGregor, D., and Feeny, A. G. April 17, 1926. Two-stroke-cycle engines.-A double-acting engine has a hollow piston 16 working inside a cylinder 15 and over a second cylinder 11; an annular enlargement 30 on the piston skirt works in a chamber formed between the cylinder 11 and another cylinder 20. The combustion chambers are formed above the piston 16 and above the annular enlargement, a sparking-plug 50 being provided for each combustion chamber. An auxiliary piston 39 connected to the main piston 16 by a rod 40 acts as a pump plunger for supplying mixture to the annular combustion chamber; the charge for the other chamber is pre-compressed within the hollow piston. Inlet passages 65, 70, Fig. 2, to the pump chambers and transfer passages 55, 60, Fig. 1, from these chambers to the combustion spaces are formed in the thickened flange 58 of the cylinder 15 and the end wall 42, ports 57, 72 in the piston skirt controlling the connection of the pump chambers to the transfer passages. The exhaust ports 51, 52 are uncovered by the piston heads. The side of the annular chamber separated by the piston head 30 from the combustion chamber is connected to atmosphere to allow air to circulate freely. The transfer passage 55 is so formed that the port 57 in the piston after having placed the lower end 56 of the passage in communication with the piston interior does not pass over the delivery end 55 on the instroke of the piston 16. Instead of placing the inlet passages 65, 70 to the pump chambers on opposite sides of the cylinder as shown they may be placed side by side in the flange 58 and wall 42, inlet from the carburettor being controlled by a rotary valve; or admission to the cylinder 11 may be by a port in this cylinder controlled by the piston 39.