GB190929183A - Improvements in Internal Combustion Engines. - Google Patents

Abstract

29,183. Cummins, W. R. Dec. 14. [Cognate Application, 1720/10.] Two-stroke-cycle engines; four - stroke - cycle engines.-The reciprocating parts are cushioned, and air under pressure for scavenging is obtained by closing the front end of the power cylinder or an extension of the power cylinder and placing a port in the cylinder wall, which leads to an air-reservoir, and which is overrun by the piston near the end of its stroke. The use of the closed front end of a cylinder for carrying out the invention is shown in Fig. 2 in connexion with a four-stroke-cycle engine. When the piston 2 is at the end of its in-stroke, air enters the closed front end of the cylinder 1 through ports 8, which may be replaced by a valve. On the down-stroke, this air is compressed into a receiver 10 until the piston overruns the port 9, after which air is trapped below the piston and is compressed to form a cushion. The mixture-inlet valve is shown at 16, the exhaust valve at 17, and the scavenging- valve, which is actuated from the half-speed shaft, at 11. On the return stroke, the air below the piston gives back the work done in its compression. A similarly - constructed twostroke.- cycle engine cylinder has terminal exhaust ports and has its power piston connected by a rod to the piston of a mixturepump. The use of an extension of the power cylinder for carrying out the invention is shown in Fig. 4 in connexion with a two-stroke-cycle engine. The ports for admitting air below the piston 19 are shown at 8, the air-receiver at 10, and the port leading thereto at 9. On the outstroke, a charge is drawn past the valve 12 into the back end of the extension cylinder 18, and is delivered on the in-stroke past the valve 15 to the receiver 14. The valves 11, 16 may be mechanically actuated or automatic. The exhaust port is shown at 7. As an alternative, the back end of the cylinder 18 may supply scavenging-air, in which case the port 9 is dispensed with. A four-stroke-cycle engine with an extension cylinder is described in which cushioning is effected on the out-strokes and on the exhaust in-strokes. The valve leading to the air-receiver is in this case mechanically actuated. The valves 11, 16 in each case may be co-axial, may be of the mushroom or piston type, and may be worked by one spindle.