Abstract: An internal combustion engine fuel injector having a selectively openable nozzle (10) through which fuel is delivered to a combustion chamber of the engine. The nozzle (10) comprises a port (12) having an internal annular surface (13) and a valve member (20) having an external annular surface co-axial with respect to the internal annular surface. The annular surfaces being shaped so that when the internal and external annular surfaces are in sealing contact closing the nozzle the maximum width (17) of the passage between the surfaces is not substantially more than 40 microns, preferably not more than 20 microns, in the direction normal to the surfaces.

Abstract: An internal combustion engine having a cylinder head at one end of the cylinder, a piston mounted for reciprocation in the cylinder, a cavity in the cylinder head, and a fuel injector nozzle located in the cavity in the cylinder head to deliver fuel into the cavity in a direction towards the piston. The piston has a bowl in the top thereof, positioned to intersect the path of delivery of the fuel from the injector nozzle. A rim extends around the periphery of the bowl and is upstanding from the to surface of the piston. The bowl and rim effect containment of the fuel, particularly during high fueling rates, to control the combustion process.