US Patent 7165535 Fuel rail pulse damper with improved end crimp

An internal pulse damper for use in a fuel rail for an internal combustion engine. The damper is formed from a length of tubular metal stock having a flat oval cross-section and ends flattened by crimping to form a captive-air pillow. The end crimps are improved through use of tooling to eliminate a creased sidewall area vulnerable to stress failure in prior art pulse dampers. Such tooling includes constraints to prevent the tubing sides from flaring out and forming a longitudinal crease adjacent the end crimp during squeezing-shut of the tube end.