Patent GB-276087-A (GB)
Title: Improvements in the construction and method of working internal combustion engines
IPC: F02B75/02
Filed: 1925-12-01
Abstract: 276,087. Le Mesurier, H. E. Dec. 1, 1925. Two-and-four-stroke-cycle engines are compounded either by using the underside of the power cylinders as the low pressure cylinder or by using independent cylinders. In a four-strokecycle engine the exhaust from the power cylinder is passed to the crank case and acts on the piston during the main exhaust stroke; the outlet from the crank case may be uncontrolled or a poppet or disc valve may be used to allow the expanded exhaust to escape to atmosphere. The disc valve is driven from the crank shaft and may be inside or outside the crank case. In another arrangement using a two diameter piston a, Fig. 14, the exhaust from the combustion chamber b is passed by a pipe 1 to the front end of the cylinder, the final exhaust through the pipe 2 being controlled by a plate valve 13; this arrangement is also applicable to cylinders and pistons of one diameter. The plate valve which also forms the partition separating the crank-case from the cylinder rocks with the connecting rod and may be curved. Ball joints f, Fig. 23, may be provided between the connecting rod 11 and the sliding partition. With this sliding partition arrangement the connecting rod may be of oblong cross-section and the final exhaust valve may be independent of the partition. The cylinders and pistons may be of one or two diameters. In a multi-cylinder engine the crank chambers are maintained independent of each other, the final exhaust taking place through disc valves mounted in the crank case and running at either half or crank shaft speed. In a co-axial cylinder engine with a common crank case the exhaust is passed into the case and acts in the pistons simultanecusly. In a four cylinder engine the exhaust from any one cylinder is further expanded in two low pressure chambers; the outlet pipes 1, Fig. 34, are cross-connected in pairs as shown and final exhaust disc valves 7 are used. When the piston drives through a piston and connecting rod, the front end of the cvlinder is closed and used as the expansion chamber. In two or four-stroke double acting engines or in two stroke engines using the front side of the main cylinder or the crank case for pre-compressing the charge an independent cylinder is used for further expansion of the exhaust from the combustion chamber. With two four-stroke cylinders one double acting expansion cylinder g, Fig. 42, is used the exhaust pipes 1 being connected as shown. In a twostroke engine the front side of the main cylinder may also be used as the expansion chamber. In V-engines the exhaust may be passed to the common crank-cases. The power pistons may be provided with piston rings at their lower ends to prevent the expanding exhaust passing around the pistons. Hot water may be injected into the exhaust before their second expansion; the water is supplied to a float chamber 30, Fig. 49. which with its supply tank is subjected to the pressure in the exhaust pipe 1 through connecting pipes 32. The means described in Specification 239,896 for dealing with the exhaust may be used with the exhaust from the expansion chamber; or a condenser for the steam in the final exhaust mav be used. Crank chambers.-The crank chambers mav be lagged with magnesia and the interiors and the bearings and parts moving in the chambers may be lacquered or painted to prevent attack of the exhaust gases. Cylinders, cooling. - The cvlinders and pipes may be lagged to prevent heat loss; internal cooling by injecting water as described in Specification 239,896 may be used. Reference has been directed by the Comptroller to Specifications 12165/92, 23359/08, 4987/12, and 180,068.