GB509111A - Improvements in or relating to control apparatus for reciprocating piston engines of the free-stroke type - Google Patents

Abstract

509,111. Speed governors. KILBURN, B. E. D. (Sulzer Freres Soc. Anon.). Nov. 1, 1938, No. 31583. [Class 57] [Also in Groups XXVII and XXVIII] Reciprocating engines operating with freestroke pistons are controlled by a device which measures off a quantity of controlling-fluid in accordance with the speed of the piston, or a part connected thereto, at a given point in, or during a given section of the stroke, the amount of fluid measured off being used to determine the setting of a control member, which may vary the quantity of fuel supplied to the engine, e.g. by adjusting the length of the suction stroke of the fuel pump. In engines with an oscillating or rocking fly-wheel mass and an invariable outer dead-centre, the controlling- fluid is measured off in accordance with the angular speed of the fly-wheel mass. Fig. 1 shows one form of apparatus in which a fuel pump 1 supplies fuel to an injection valve 8 when the plunger 1 is forced downwards by pressure fluid admitted above a plunger 10 from a supply 11 and pipe 13 controlled by a valve 12, which also controls a discharge port 46 for the actuating-fluid. The suction stroke of the pump 1 is effected by a spring 31 and lever 28 under the control of a piston 30, to the underside of which a quantity of controlling- fluid is admitted as measured off by a device comprising a measuring-valve 43 actuated by a cam A and having a discharge port 45 and a supply pipe 35 fed by a pump 40 actuated by a cam C. The inlet of controlling-fluid from a connection 33 to the pump 40 is controlled by a valve 34 actuated. by a cam B and by a plunger 37 subject to the pressure in the pipe 13. The cam-shaft 14 is oscillated to and fro by the reciprocation of the free-stroke pistons. The valve 12 is actuated by a cam D and a tappet comprising two parts 20, 21 having a space 19 between them, to and from which fluid is supplied or discharged from connections 26, 25 controlled by a valve 22 actuated by a cam E. When the recess in the cam A becomes operative, the valve 43 is moved to open the discharge 45 as shown, and the control piston 30 is moved downward for producing the suction stroke of the fuel pump 1. The amount by which the piston 30 is allowed to move downwards depends on the amount of fluid measured off by the,valve 43, namely the amount by which the supply forced by the pump 40 through pipes 44, 35. exceeds the discharge at 45, this amount being proportional to the speed of the free-stroke piston connected to the cam-shaft 14. The valve 43 is then closed and the tappet 20, 21 raised to open the valve 12 to admit the fluid from 11 for effecting the pressure stroke of the fuel pump 1. At the same time, this fluid acts on the plunger 37 to move the valve 34 downwards so as to connect the pipes 35, 36 to the supply of controlling-fluid at 33, thereby refilling the chamber 32. When the tappet 20, 21 is raised, the space 19 becomes filled with fluid from passages 26, 16 so that the valve is maintained in its raised position, until the valve 22 is raised by the cam E to discharge the space 19. The valve 22 may be omitted and the tappet 21 actuated by a double cam. Two cams C are provided, one or other of which is brought into action by a rocking fork 55 as the stroke of the free piston is reversed. Similarly, two cams B could be provided for the valve 34, the fluid actuation being omitted. The setting of the valve 43 may be adjusted in accordance with the supercharging pressure, by an eccentric fulcrum 48 and piston 50. In a modification, the measured amount of controlling-fluid adjusts the suction valve of the fuel pump. The air supply may also be controlled by this measured fluid.