GB1233011A - - Google Patents

Abstract

1,233,011. I.C. engines. AMERICAN GAS ASSOCIATION Inc. Oct.23, 1968, No.50348/68. Heading F1B. A stratified charge internal combustion engine comprises, Fig.1, a piston 18 running in a cylinder 14 having a head 22 in which is mounted a gaseous fuel intake check valve assembly 30. The latter comprises a flanged valve seat ring 34 held in position in the cylinder head 22 by an internally and externally threaded retaining sleeve 38 which surrounds a valve guide member 42 and its hollow retaining nut 46. The guide member 42 has a central spider 48 which slidably supports a check valve 50 urged to the closed position by a spring 52. Gaseous fuel, such as natural gas, methane, propane or butane, is supplied under low-pressure to the valve assembly 30 through a pipe 58. A glow plug 60 is disposed in the cylinder head 22 with its glow wire 64, of platinum-rhodium or platinum-tungsten material, projecting into a pocket 32 adjacent the check valve head 54. The engine may be a two-stroke and during the scavenge and charging stroke, shown, of piston 18, air from the engine crank-case is forced through a pair of facing ports 66 in the cylinder 14 so that each airstream follows a loop-like path to a single exhaust port 68. The arrangement is such that the reducedpressure in the cylinder causes valve 50 to open and admit fuel gas which is drawn by the looping air-flow downwardly along the wall of the cylinder as a localised cloud 70. As the piston 18 moves upwardly on the compression stroke, Fig.3 (not shown), ports 66, 68 and valve 50 close and the fuel cloud 70 is forced upwardly until near T.D.C. the cloud moves into pocket 32 and across the glow wire 64. When the fuel mixture in the region of the glow wire is sufficiently rich, the wire ignites the cloud 70 which ignites the remainder of the charge in the combustion chamber. For satisfactory operation, the glow plug 60 must be positioned substantially along or upstream of, a plane passing through the check valve 50 perpendicular to the charging air-flow past the valve. Current is supplied to the plug 60 only at starting, thereafter combustion heat maintains the wire 64 glowing. In a modification, Fig.6, the engine is of the opposed piston uniflow type having pistons 86, 88 running in a horizontal cylinder 84 to define a combustion chamber 90 into which open air intake ports 92 and exhaust ports 94. Aligned with the transverse centre line of the engine are a spring- loaded gaseous fuel check valve 96 and a diametrically opposite glow plug 102. The introduction and ignition of the gaseous fuel cloud 106 takes place in somewhat similar manner to the Fig.1 embodiment. The opposed faces of the pistons 86, 88 are relieved in the area of the plug 102 to facilatate the movement of the charge into and through the glow plug region. The construction is applicable also to four-stroke engines.