Patent GB-825761-A (GB)
Title: Control systems for compound power units
Inventor: WOOD-COLLINS CHARLES ALLISTER
IPC: F02B37/16
Filed: 1956-05-16
Abstract: 825,761. Motor power plant. NAPIER & SON Ltd., D. May 3, 1957 [May 16, 1956], No. 15280/56. Class 110 (3). [Also in Group XXVII] A motor power plant comprising a reciprocating internal engine with an exhaust gas turbine driven supercharger has a disengageable coupling between the engine crank-shaft and the turbine supercharger rotor, one or more auxiliary combustion chambers situated in the exhaust ducts or ducts of the engine in advance of the turbine into which a variable quantity of fuel may be injected, a controllable by-pass by which air may pass from the supercharger directly to the engine exhaust passage in advance of the auxiliary combustion chamber or chambers and a device sensitive to the speed of the engine crank-shaft to control automatically the engagement and disengagement of the coupling so that the coupling is disengaged at low speeds and engaged at higher speeds. The exhaust of a multi-crank-shaft twostroke compression ignition engine passes through a passage 69 containing one or more auxiliary combustion chambers 6 to a turbine which drives an axial flow compressor supplying air to the engine. One or more passages 71 controlled by valves 72 connect the delivery of the compressor and the turbine inlet passage 69. The turbine-compressor rotor may be connected to the engine crank-shaft by a controllable fluid coupling 75 in which the quantity of fluid therein can be varied to vary the degree of slip in the coupling. The fuel supply to the reciprocating engine is controlled by a variable datum hydraulic speed governor 1 which may be of the form described in Specification 724,023, [Group XXIX]. A pair of governors 4, 5 responsive to the speed of the turbine-compressor rotor are also provided. Fuel is supplied to the combustion chamber 6 through metering apparatus 8 comprising a variable delivery pump 9 which is controlled to maintain the pressure drop across the metering orifice 10 constant. The effective area of the metering orifice is controlled by two independently-operable sleeves 11, 12. The sleeve 11 is controlled by the governor 1 acting through a servomotor 15. The sleeve 12 normally remains stationary but is actuated by a piston 21 when the speed of the turbine-compressor unit approaches its minimum self-sustaining speed. The governor 5 then opens valve 22 to increase or initiate the delivery of fuel to the combustion chamber 6. An igniter control device 23 has a piston 24 which is forced downwards by the fuel pressure to close a switch which energizes an igniter 86. A temperature responsive device 28 controls a switch 29 which switches off the igniter 86 when the combustion chamber has ignited and at a considerably higher temperature to shut down the whole of the fuel injection apparatus. The governor 5 operates contacts 36 to shut down the fuel system when the speed of the turbine-compressor unit exceeds a predetermined maximum value. The governor 4 controls through a valve 33 the filling of the coupling 75. The loading of the spring of the governor 4 is adjustable by a cam 35 connected to the piston 14 so that the operation of the valve 33 is in accordance with the relationship between the speeds of the reciproeating engine and the rotor of the turbinecompressor unit. The plant is started by an electric motor driving the turbine-compressor unit with the coupling 75 disconnected. Fuel is injected into the combustion chamber 6 so that the unit is self sustaining. The fluid coupling 75 is then progressively filled and the reciprocating engine started. If necessary, during this operation, the by-pass valve 72 may be opened by the starting lever 88. During normal operation, the coupling 75 is disconnected until a predetermined reciprocating engine speed is reached after which the coupling is progressively filled until a second predetermined speed is reached after which the coupling is completely filled.