German Patent Application No. 28 29 057, discusses a fuel-injection system for supplying fuel to a mixture-compressing internal combustion engine having external ignition as a function of operating parameters. The fuel-injection system includes a metal fuel-distributor line, which, via at least one branch line, is connected to at least one fuel injector, the branch line being embodied as a metal tube and connected to the fuel injector by way of a threaded connection. Easily bendable metal is used as material for the branch line. Situated between the threaded connection on the branch line and the fuel injector are thin-walled metal bellows, which compensate for a lateral offset between the beginning point of the branch line on the fuel-distributor line and the fitting position of the fuel injector, and which damp the operating noises originating in the fuel injector.
Disadvantageous in the fuel-injection system from German Patent Application No. 28 29 057 is that the screw connection is not secured against an automatic loosening. Due to the vibrations of the internal combustion engine during operation, a screwed connection rigidly connected to the internal combustion engine is at a higher risk of coming unscrewed.
However, especially in the case of directly injecting fuel injectors and at the high pressures required in this context, the screwed connection is safety-relevant and should not come unscrewed under any circumstances. The known fuel-injection system provides no suggestion for securing a screwed connection.