| 摘要 |
PCT No. PCT/IE92/00020 Sec. 371 Date Aug. 8, 1994 Sec. 102(e) Date Aug. 8, 1994 PCT Filed Nov. 5, 1992 PCT Pub. No. WO93/09343 PCT Pub. Date May 13, 1993.A compression operated fuel injector assembly (1) for an internal combustion engine. The injector assembly (1) has a body (2) with a bore (8) having a gas passage (9) at one end for communication with an engine combustion chamber. A piston (7) is slidable in the bore (8). A fuel pump (5) is mounted within the body (2) having a plunger (14) which is mounted on the piston (7) for reciprocal pumping movement within a complementary fuel pump cyclinder (15) for delivery of fuel to a nozzle assembly (6). The nozzle assembly (6) is mounted on the piston (7) and projects through the gas passage (9). The piston (7) is urged downwardly by a timing spring (16) so that a valve head (18) on the nozzle assembly (6) engages a valve seat (19) until the pressure of combustion chamber gases acting on the outer portion of the nozzle (6) is sufficient to overcome spring pressure and move the piston (7) upwardly opening the passage (9) to the piston (7) so that the gases snap the piston (7) upwardly due to the increased area exposed to the gases. Collets (20) at an outer end of the gas passageway (9) form a gas tight seal with a second valve head (21) on the nozzle assembly (6) when the piston (7) snaps inwardly to retain purging air within the bore (8) and seal the bore (8) during combustion to exclude combustion gases. When cylinder pressure drops at the end of the power stroke the spring (16) moves the piston (7) outwardly to blow down the purging air into the cylinder for improved scavenging. |
