Patent ID: 9234487
Filing Date: 2016-01-12
CPC Classification: F02M

Claim Text:
1. An injection nozzle for injecting fuel into a combustion chamber of an internal combustion engine, the injection nozzle comprising: a nozzle body having a bore for receiving fuel from a supply line for pressurised fuel; an outlet from the bore for delivering fuel to the combustion chamber, in use; and a valve needle defining a needle axis and being slidable within the bore between a closed state in which fuel flow through the outlet into the combustion chamber is prevented, and an injecting state in which fuel flow through the outlet into the combustion chamber is enabled, movement of the needle being controllable by varying the fuel pressure within a control chamber, in use; the needle comprising a needle guide portion arranged to guide sliding movement of the needle within the bore; the injection nozzle further comprising a restriction within the bore for restricting the flow of fuel through the bore, and a restrictive element having an upstream side and a downstream side; the restrictive element being moveable with the needle and located upstream of the needle guide portion; wherein the restriction is defined between the bore and a peripheral edge of the restrictive element, and wherein, when the needle is in the injecting state in use, the pressure of fuel at the outlet is substantially the same as the pressure of fuel in the bore immediately downstream of the restrictive element and is less than the pressure of fuel supplied to the bore from the supply line; characterised in that at least a part of the downstream side of the restrictive element comprises a bevelled surface that extends to the peripheral edge, the bevelled surface being non-perpendicular to the needle axis; wherein the restrictive element has a larger diameter than the needle guide portion of the needle; wherein the downstream side of the restrictive element comprises a downstream face that is normal to the needle axis, and wherein the bevelled surface is formed as a chamfer at the periphery of the downstream face.