GB542844A - Improvements relating to fuel injection in internal combustion engines - Google Patents

Abstract

542,844. Fuel injection pumps. KAMMER, G. S. July 25, 1940, No. 12167. [Glass 102 (i)] [Also in Group XXVII] In fuel injectors comprising a nozzle with two or more orifices controlled by separate needle valves, fuel is supplied to the needle valves from separate outlets in the pressure space of the fuel pump, one outlet being controlled by the pump plunger, and at least one other outlet being in continuous communication with the pressure space. Fig. 1 shows a pump 1 with piston 2 controlling an inlet 3 for fuel, and on outlet 5 connected to a passage 27, Fig. 4, leading to one 23 of the needle valves. A second outlet 4 is always open to the pressure space of the pump and lead to a passage 26 for the other needle valve 22. The inlet 3 and outlet 5 are controlled respectively by helical edges 6 and 7, Fig. 3, of a groove in the piston 2, the timing being varied by rotation of the piston. Fuel is first injected at a high pressure through the outlet 4 and past valve 22, and afterwards at a lower pressure through the outlet 5 and past valve 23. The spring 24 closing the valve 22 may be stronger than that 25 closing the valve 23, so that when both are being supplied with fuel pressure, the valve 22 will close. The first injection begins preferably about 2 degrees to 7 degrees before inner deadcentre, and the second either at or just after the dead-centre. The valve 22 supplies orifices 36 through passages 34, 35 and the valve 23 supplies orifices 33 through passages 29, 30, 31. The upper face of the pump piston 2 may be wholly or partly helical ; also the outlet 5 may be lower than the inlet 3, the groove in the piston 2 then having only one helical part. The piston 2 may be driven by an eccentric so that only the middle part of the stroke is used for feeding fuel. Specifications 534,724 and 535,151, [both in Group XXVII], are referred to.