Improvements in or relating to reciprocating internal combustion engines operating on the two-stroke cycle

663,296. Centrifugal and axial-flow compressors; motor power plant. NAPIER & SON, Ltd., D. March 27, 1950 [April 11, 1949], No. 9768/49. Classes 110(i) and 110(iii) [Also in Group XXVII] In a two-stroke engine of the kind having three parallel crankshafts in crankcases B, B1, B2, Fig. 4, interconnected by cylinder blocks C. C1, C2 with two pistons in each cylinder thereof connected respectively to the adjacent crankshafts and controlling respectively inlet and outlet ports in the cylinder wall, a multistage axial flow compressor F, Fig. 1, for supplying air directly or indirectly to the inlet ports is housed partially or wholly in the approximately triangular space enclosed by the blocks C, C1, C2 and crankcases B, B1, B2. As shown, the compressor F draws air through an inlet F1 at the front end of the engine and feeds it through an annular passage F5 to a centrifugal compressor G which delivers through three volutes such as G6 to split inlet manifolds such as E2, E3 supplying a ring of inlet ports in each cylinder. The compressor F is permanently drivingly connected to an exhaust-driven turbine K1, a transmission coupling L on the turbine rotor K4 having an internally toothed coupling member always engaging a meshing coupling member on a shaft H permanently coupled to the rotor shaft F2 of the compressor F. A second coupling member also permanently meshing the internally toothed member of the coupling L is fast with one element of a hydraulic clutch M2, the other element of which is fast with the rotor G' of the compressor G. The clutch M2 is of the kind which can transmit torque in both directions of power flow, and may be of the permanently filled type or, preferably, of the type the filling of which can be controlled to render it operative or inoperative. The rotor G2 has a gear J connected by independent but similar gearing trains to two of the engine crankshafts. One such train is shown leading to a gear J10 on a crankshaft A and incorporating a flexible shaft J'. The turbine K' is fed from a ring of exhaust ports in each engine cylinder, through manifolds D1, three volutes such as N' and an annular chamber N3. The whole arrangement is such that. at starting, the compressor G supplies air to the engine and, if the clutch M2 be operative, the compressor F is also rotated to reduce or eliminate air drag therethrough. In normal operation under load. the turbine K1 powers the compressor F and, if the clutch M' be operative, any excess turbine power passe