GB478422A - Improvements in or relating to internal combustion engines and to the charging thereof - Google Patents

Abstract

478,422. Two-stroke engines. FITZGERALD, W. M. B., and RATCLIFFE, T. April 14, 1936, No. 10650. [Classes 7 (ii) and 7 (vi)] In an engine in which the combustion chamber 13 is isolated from the expansion chamber 16 by a valve 17 and from a conveyer duct 11 by a valve 12, an air charge is compressed into the duct 11 through a valve which closes at the end of compression and fuel is supplied to the air charge when in, or when entering, the chamber 13 at the end of compression or immediately after ; ignition, e.g. by means of a sparking-plug 14, is effected before the end of the exhaust stroke, exhausting taking place past a valve 18 ; the valve 17 opens at top dead centre, and the spring-loaded valve 12 opens before valve 17 closes to deliver an air charge to scavenge the chamber 13. The duct 11 may be cooled, e.g. by placing it and its supply pipes 10 in the cylinder water jacket, or in a separate water jacket, or providing it with aircooled fins. The air may be compressed by the underside of the piston, or by a port thereof if a differential piston is used, or it may be supplied by a separate compressor. In a multicylinder engine, the charge in one cylinder may be compressed by the piston of another. A single conveyer duct arranged between two cylinders may serve for the combustion chambers of both. The piston closely approaches the cylinder head so that the expansion chamber is thoroughly scavenged. The engine may run on gas, light oils or heavy oils, and the isolated charge may be held in the chamber 13 for half a working stroke so that thorough mixing takes place. Specification 478,471 is referred to. Valve gear.-A shaft 56, operating the exhaust valve 18 through a rocker 55, is oscillated from a push-rod located substantially behind the valve through a rocker, pivoted coaxially with a shaft 43 and a pair of opposedtoothed quadrants.