Verfahren zur Auslegung eines Kraftstoffeinspritzventils

A fuel injector for an internal combustion engine, the injector comprising an injector body (1) having a tip portion (2) defining at least one spray aperture (3); a pintle (5) extending within the tip portion (2), the pintle (5) having a head portion (6) engageable with a valve seat (4) to close the spray aperture (3), the pintle (5) being axially moveable between a closed position wherein the head portion (6) abuts the valve seat (5) and an open position wherein the head portion (6) is spaced from the valve seat (5); actuating means for selectively urging the pintle (5) towards its open position; guide means (12) being provided within the injector body (1) guiding the pintle (5) for axial movement between its closed and open positions; a fuel supply chamber (16) being defined within the injector body between the spray aperture (3) and the guide means (12), characterised in that the diameters of the guide means (12) and valve seat (4) are selected such that the pintle (5) is substantially pressure balanced.