GB736581A - Improvements in or relating to the supply of scavenge and combustion air to two-stroke cycle internal combustion engines - Google Patents

Abstract

736,581. Supercharging and scavenging. DOXFORD & SONS, Ltd., W., PURDIE, W. H., and JACKSON, P. Jan. 18, 1952 [Jan. 24, 1951], No. 1834/51. Class 7(2). In a two-stroke multi-cylinder Diesel engine of the type having in each cylinder two opposed pistons each connected to a common crankshaft by one or more connecting rods and having one or more reciprocating pistontype air-compressors 1, 2, Fig. 3, for supplying scavenging and combustion air, the or each compressor being engine driven by linkage from the piston or connecting rods, there is provided a turbo-blower 8 actuated by the engine exhaust independently of the engine mechanism and arranged to supply air to the piston compressors 1, 2 thereby to increase the compressor output according to the volume and pressure of the exhaust gases. The compressors 1, 2, which are driven from the crossheads of the two end engine cylinders 6, 7, deliver air into the engine casing 16 from whence it passes to the engine. The turbo-blower 8 delivers air through an intercooler to a manifold 13 which is the common inlet to compressors 1 and 2. A bypass pipe 14 with a weight or spring closed non- return valve 15 therein may be provided around the compressors, the valve 15 opening when the pressure on the blower side of pipe 14 exceeds the pressure in the engine casing 16. In a modification, three compressors 20-22, Fig. 4, are driven from the end cylinders of a sixcylinder engine whilst two turbo-blowers 26, 27 are each driven by the exhaust gas from three cylinders and feed air to a manifold 31 through intercoolers 33, 34 and pipes 30, 32, respectively; by-pass pipes 35, 36 with non-return valves therein may be provided between pipes 30, 32 and the engine casing 39. Two compressors may be provided at opposite ends of the engine and each of the two blowers is arranged to deliver air independently to the compressors feeding the cylinder from which each blower is driven. More than two blowers may be provided each driven by the exhaust gases from a cylinder or group of cylinders. In a further modification, three piston compressors 40-42, Fig. 7, have their inlets connected to a reservoir 49 supplied with air from a turbo-blower 43 through a pipe 47 and an intercooler 48 ; the turbo-blower is arranged vertically and mounted at the rear centre of the six engine cylinders. The compressors deliver into the engine casing 51 whilst a by-pass pipe 50 and non-return valve 52 may be provided between reservoir 49 and casing 51 so enabling the compressors to be by-passed under given pressure conditions. When a by-pass is provided the capacity of the compressors is only sufficient to deliver the air required by the engine at partial load, the by-pass enabling additional air to be supplied direct from the turbo-blower. Specifications 244,032, [Class 7(ii)], and 580,704 are referred to.