Patent GB-618046-A (GB)
Title: Improvements in or relating to means for controlling internal combustion engine plants for marine propulsion
IPC: B63H21/22
Filed: 1944-08-10
Abstract: 618,046. Fluid-pressure servomotor-control systems. SULZER FRERES SOC. ANON. Aug. 10, 1944, No. 15212. Convention date, Aug. 23, 1943. [Class 135] [Also in Group XXVII] The control of a ship-propulsion plant comprising a two-stroke internal-combustion engine, an exhaust-actuated turbine and a supercharger, is such that when the load is increased, the plant is first speeded up by lowering the pitch of the propeller, thus increasing the supercharging pressure, the quantity of fuel is then increased and the pitch of the blades replaced. Fig. shows an engine 1 having an exhaust pipe 8 and a turbine 7 driving a compressor 18 which is also driven from the crankshaft 3 through a free-wheel coupling 21. and reducing gear 20 when the power of the turbine is small. Fuel is suppled by pumps 26 and the pitch of the propeller blades 5 is adjustable by moving a piston 14. If the speed of the ship is to be increased, a control lever 27 is moved to position II, and this causes a lever 34 to turn about its fulcrum 35 and its end to take up the position 38a. This operates a servomotor valve 17 and the piston 14 moves to the right and lowers the pitch of the blades 5. The engine now increases in speed and the pressure in the supercharging pipe 12 rises. At the same time the fuel supply is increased owing to the increased supercharging pressure acting on a piston 36 coupled by a rod 42 to the fuel pump control rod 47. The piston 36 also displaces the fulcrum 35 of the lever 34, and with it the control valve 17 and the piston 14 returns to its original position and puts back the pitch of the propeller blades. For decreasing the speed of the ship, the lever 27 is moved to the position O, thus decreasing the fuel supply. Lost-motion, comprising a spring 45 acting on a plate 44 in the connection with the lever 34, allows this to be done without altering the pitch of the propeller. When, however, the lever 27 is moved to the right, the end of a, rod 50 moves freely in a slot 49 so that the fuel supply is only changed in accordance with increased supercharging pressure. The pitch of the propeller can be adjusted by hand through the rod 15 or through the servomotor by manual operation of a lever 53. The Specification, as open to inspection under Sect. 91, comprises also details of the servomotor shown in Figs. 4 and 5 (Cancelled). When the lever 34 is moved about its fulcrum 35, as explained above, a rail 36, Fig. 4 (Cancelled), having a slot 37 is moved transversely. The rail carries a slide 38 having two pins 39 which engage both the slot 37 and slots 40, 41 in a rod 42, and a rod 43 connected to a control valve 17. Opposite sides of the piston 14 are thus connected to an oil supply pipe 46 and a drain pipe 47. The slide 38 takes up the position 38a, Fig. 5 (Cancelled), and the lever 43 is moved to position 43a. This causes the control valve 17 to move to the left and the space 44 to be connected to the oil supply pipe 46. After the piston 14 has moved to the right the control valve 17 is returned by the lever 43 which takes up the position 43b. In Fig. 10 (Cancelled), the turbo-blower 7, 18 is connected to an electric motor 19 which is continuously connected to the ship's electric circuit, but designed so that it can follow the change of speed when the engine load increases. The propeller pitch is altered by a piston 97 of a servomotor 98. The operating medium, which is supplied and drained by pipes 99, 100 is controlled by a rotary valve 101 and by either of the valves 102, 103 according to whether the ship is to move forward or astern. The two valves are connected to a lever 106 which is itself pivoted to the end of a rod 108 connected to a lever 109. The rod 71 controlling the fuel pumps is connected to a lever 112 against which the lever 109 is pressed by a spring 114. The lever 112 is held by a notched segment 116. As shown, the ship is at rest but the controls are set for motion ahead. The pipes 99, 100 are connected by the rotary valve 101 to the valve 102 and the fulcrum 107 of the lever 106 is positioned so that the piston 97 is in its middle position. If the ship is to be driven ahead, the lever 112 is moved to the position 10. The rod 71 is thus moved to admit fuel to the engine, the amount being limited by a governor. The lever 109 can now be moved by releasing the gear 118, and the spring 114 presses it against the stop on the lever 112. The valve is thus displaced so that pressure medium passes into the pipe 99 and moves the piston 97 to adjust the propeller blades. The lever 106 also moves until the valve 102 is returned to its middle position, thus stopping the movement of the piston 97. If the ship is to be driven astern, the lever 117 is moved to position R and similar action takes place through the valve 103. This subjectmatter does not appear in the Specification as accepted.