Sealing arrangement for injection valves in fuel feed lines

摘要

PCT No. PCT/EP95/01212 Sec. 371 Date Jan. 30, 1997 Sec. 102(e) Date Jan. 30, 1997 PCT Filed Mar. 31, 1995 PCT Pub. No. WO95/29336 PCT Pub. Date Nov. 2, 1995A sealing system for connecting a valve for fuel injection in combustion engines to a fuel rail. Prior art systems employ an O-ring as a sealing element seated in an external groove of the valve housing which ends with a groove limiting flange adjacent to a bore in the rail, whereby the O-ring has to seal radially inside (groove bottom) and outside (wall of the hollow to include the valve). The disadvantage of such known systems is that under low temperature operation conditions special material properties of the O-ring are required and that radial external leakage occurs when the material swelling decreases owing to operation stoppage. The present invention results in system leak-tightness even in temperatures below 40 DEG C. and in the case of insufficient material swelling. The present invention is a sealing system in which the radial inner sealing surface of the sealing element is axially expanded and is overlapping to an additional ring surface at the rail producing a sealing contact with the surface and in which the thermal expansion coefficients of the sealing element and the contacted metallic parts behave in such a way relative to each other that the element during cooling down shrinks radially in an inward direction. This results in tightness even under very low operation temperatures even when the sealing element is of usual material without specific thermal properties.