Fuel injection nozzles

Claim 1

A fuel injection nozzle for supplying fuel to a combustion chamber of a compression ignition engine, comprising a bore, a seating defined in the bore and a valve member shaped for co-operation with the seating and movable away from the seating by the action of fuel under pressure supplied to the bore, to allow fuel flow through an outlet, a guide bore extending from said seating to the exterior of the nozzle, an extension on said valve member, said extension being slidable within said guide bore, a chamber defined in said extension, said chamber having an open end defining the outlet to the exterior of the nozzle, a first flow passage in the extension, said first flow passage opening into said chamber at a position so that fuel flowing therethrough when the valve member is lifted from its seating will swirl in one direction in said chamber, thereby to cause the fuel spray leaving said outlet to be of bushy form, and a second flow passage in the extension, said second flow passage being arranged to be progressively uncovered as the valve member moves away from the seating, said second flow passage being disposed so that fuel flowing therethrough cancels the swirl produced by the first flow passage thereby to cause the fuel to leave said outlet in the form of a jet.