GB1453111A - Fuel injector for an internal combsution engine - Google Patents

Abstract

1453111 Fuel injector pumps; IC engine fuel injectors CUMMINS ENGINE CO Inc 14 Jan 1974 [15 Jan 1973] 01690/74 Headings F1A and F1B A fuel injector comprises an adapter 101 having an inlet duct 165, and return ducts 176, 177; a barrel 102 secured to the adapter by a retainer 103 and having a feed port 173, a scavaging port 174, a drain port 179, and a spill port 178; a plunger 127 biased upwardly by a spring 131 and having grooves 181, 182 which can allow communication between ports 174, 179 and a fuel chamber 194 and port 178 respectively; and a valve 141 mounted in the fuel chamber 194 and having a portion 143 which can seat in the tip of the injector to close the fuel orifices 146. When the plunger is in its uppermost position, Fig. 4, fuel passes the feed port to the fuel chamber 194. The ports 174, 179 and 178 are closed by the plunger. On downward movement of the plunger, the feed port 173 is closed and the scavaging port 174 opened Fig. 5 (not shown). The fuel level in the chamber 194 is well below the plunger base. Further downward movement of the plunger pressurizes the fuel which passes from the chamber 194, through circumferential grooves (189) Fig. 7 (not shown) in the valve 191 to the injector sac and through the orifices 146. When the portion 143 rears its seat to cause a sufficiently large pressure drop across it, the valve 141 moves away from the plunger to close the orifices, Fig. Further downward movement of the plunger causes its base to contact the valve 141 again and at the same time open the spill port (178) Fig. 3 (not shown). In an alternative embodiment Figs. 10 to 12, (not shown) a groove (241) can inter-connect the spill port (242) with the drain port (236). When the plunger is in its uppermost position the valve (251) abuts the lower end of the barrel. Fuel passes into the fuel chamber through the feed port (232, Fig. 10). Thereafter the port (232) is closed and fuel is forced through the injector orifices. The plunger base then contacts the top of the valve until the pressure drop across the seat is sufficient to force the valve closed (Fig. 11). When the plunger re-engages the valve, the spill port 242 and the drain port (236) are placed in communication with one another by the groove (241). In another embodiment Fig. 13 (not shown) fuel flows from the fuel chamber to the sac via a bore in the injector cup (272) and not circumferential grooves in the valve. Figs. 14 and 15 (not shown) illustrate an embodiment in which highpressure fuel spills into a closed space (343) rather than directly to a drain connection, the closed space subsequently communicating with the drain connection on further movement of the plunger. The valve may be connected by lost motion to the plunger instead of merely abutting it Figs. 16 to 19 (not shown).