NOZZLE AND NEEDLE OF A HIGH-PRESSURE UNIT FUEL INJECTOR

摘要

A unit fuel injector (30) has a nozzle (36) providing axial guidance of a needle (72) at points proximal and distal to a needle feed cavity (81). The needle has a multi-lobular formation (200) providing distal guidance of the needle while allowing fuel from the needle feed cavity to flow past for injection from orifices (86) when the needle is unseated from a seat on a tapering surface (82). Fuel is delivered to the needle feed cavity through a slant passage (85) in the nozzle non-parallel to a longitudinal axis (AX) along which the needle is displaced. The orifices are arranged in a hemispherically contoured surface (83) distal to the seat and centered on a point on the longitudinal axis. The orifices have circular transverse cross sections. The axis of each orifice extends radially of the point on the longitudinal axis at an oblique angle to the longitudinal axis.