Patent GB-830963-A (GB)
Title: Improvements in or relating to fuel injection systems
Inventor: MANSFIELD WILFRED PERCIVAL
IPC: F02M59/10
Filed: 1955-01-14
Abstract: 830,963. Fuel injection systems. BRITISH INTERNAL COMBUSTION ENGINE RESEARCH ASSOCIATION. Jan. 9, 1956 [Jan. 14, 1955], No. 1170/55. Class 7(3) [Also in Group XXVIII] A fuel injection system for an I.C. engine comprises a source of pressure liquid, an accumulator receiving said liquid, a liquid pressure operated injection pump, pressure liquid flow control means operated in timed sequence controlling flow from the accumulator to operate the pump and adjustable means for controlling the discharge of pressure liquid from the pump actuating cylinder by way of said flow control means to a zone of low pressure whereby the return stroke of the fuel injection pump plunger is controlled by the rate of discharge of pressure liquid through the adjustable means. In the embodiment shown in Fig. 1 an engine driven pump E draws fuel from tank C and supplies combined accumulator, injection pump and injectors Z via a pressure regulator F and filter 1; the members Z also include the flow control means. The outlet from the members Z passes by a pipe K through the adjustable means L for controlling the discharge to the tank C. The members Z (see Fig. 2), comprise a pneumatic accumulator chamber 1 separated from an inlet chamber 6 by a diaphragm 3, the chamber 6 being in communication with the pump E. The outlet 24 communicates with the pipe K. The inlet and outlet ports 11, 23 are controlled by a valve 10 operated in one direction by a piston 21 supplied with pressure liquid in timed sequence by a distributer N driven by the engine and in the other direction by a spring 22 or vice versa. When the port 11 is uncovered, pressure liquid is supplied to the pump actuating cylinder 12 and acts on a piston 13 which in turn actuates a plunger 14 to discharge fuel through the nozzle 16. At the end of the injection stroke a duct 31 may open to port 33 so that fuel is bypassed to the inlet 26. When the discharge port 23 opens pressure liquid passes from the inlet chamber 6 through the inlet passage 26 and inlet valve 25 to the pump chamber 15 and the pressure of this liquid forces the plunger 14 and piston 13 upwards. The return stroke of the plunger and piston is dependent on the setting of the throttle valve L which controls the rate of out flow and hence the position of the plunger and piston when the port 23 is again closed. The valve 25 incorporates a cylindrical portion 36 and also a head 42 arranged to close the passage 43 when the valve 25 is fully open so preventing fuel passing to the engine should the injector valve stick. The injector valve 17 is hydraulically loaded by the pressure in the passage 26. In a modified arrangement of device, shown in Fig. 8, the transverse slide valve 10 is replaced by a valve 57 which is coaxial with the piston 13. In a modification of the system as shown in Fig. 5 valves such as 10 are not fitted to the devices and the operating pistons R of the injection pumps are controlled directly by the engine driven distributer S. A common accumulator W is provided. In the embodiments so far described the actuating liquid is the fuel oil which is also supplied to the injection cylinder; further embodiments are described in which the engine lubricating pump supplies pressure liquid for actuating the injection pump, a separate fuel feed pump being provided. A manually or automatically adjustable timing device may be fitted between the distributer N and engine shaft. The injector nozzle may be cooled by conveying oil discharged into the port 23 to cooling passages in the nozzle and thence to the outlet 24. Specification 746,280 is referred to.