GB804024A - Improvements in gas engines - Google Patents

Abstract

804,024. Working cycles; cylinders; valves and valve gear; regulating. COOPERBESSEMER CORPORATION. Feb. 10, 1956 [March 14, 1955], No. 4209/56. Classes 7(2), 7(3) and 7(6) A gaseous main fuel charge commencing to enter a main combustion space 30, Figs. 1 and 2, just before an air charge therein reaches full compression is dispersed and ignited by a stream of hot gases formed by ignition in an auxiliary combustion chamber 5 of a fuel/air mixture too lean for self-ignition. The invention is applicable to four-stroke engines but a twostroke engine is shown. The main charge is supplied from a high pressure (800 to 1000 1bs. per square inch) source 16 via a non-return valve 23 and a valve 14 the return spring chamber of which has a vent 22. The lean fuel/air mixture is ignited by a spark-plug 22 or a pilot injection of oil and is formed by charge air mixed with gas supplied from a source 9 via a non- return valve 11 and a valve 6. The valves 6, 14 are conjointly operated by a rocker 26 having a return spring 27. The valve 6 may open fairly early or late in the compression stroke, the valve 11 closing when the cylinder pressure exceeds the supply pressure of 100 or 200 lbs. per square inch respectively. The lean fuel/air mixture is ignited from 2 to 15 degrees before top dead centre, and the main fuel supply commences from 8 to 15 degrees before, and ends from 10 to 15 degrees after, top dead centre. Piston-controlled exhaust and air inlet valves are provided. The engine may be fuelled by natural gas or by methane, ethane, propane, butane, hexane, pentane or mixtures thereof. Regulation may be effected by varying under governor control the pressure and therefore quantity of the main gaseous charge only, the gaseous charge quantity supplied to the chamber 5 remaining constant at all loads and being preferably less than is necessary to operate the engine at idling. Reliable low-load running is thus achieved.