Common rail fuel injector adjusting gasket

Common rail fuel injector adjusting gasket:

In the production process of the fuel injector, these five gaskets are not randomly selected, but are calculated after a step by step fine measurement, the accuracy is in micron (1/1000 mm). Why is the thickness of each gasket so precisely defined? This is because each adjusting gasket has a significant effect on the performance of the injector.

Valve spring adjusting gasket: adjust the solenoid valve spring force. Different types of injector valve spring force set value is not the same. The valve spring force setting value of CRIN injector varies from 58N to 85N with maximum allowable tolerance of 3N. Too large or too small valve spring force will affect the corresponding area of the fuel injection size.

Armature lift shims: adjust the maximum displacement of the ball valve up and down (armature lift). Armature lift Settings of different injectors are different. The armature lift value of CRIN ranges from 40 micron to 60 micron, and most of the CRIN2 injectors in the Chinese market are 52 micron or 55 micron, with a maximum allowable tolerance of 5 micron. Too large or too small armature lift will directly cause the injector not to spray oil or the injection is too small. For a CRIN injector, within the normal deviation of the set value (5 micron), the armature lift only affects the amount of pre-injection oil, and does not affect other injection points.

Buffer lift adjusting gasket: adjusts the maximum displacement of the armature during operation. The cushion lift gasket must not be too thick, or it will directly cause the fuel injector to return a large amount of oil. The setting values range from 20 micron to 60 micron with a maximum allowable tolerance of 20 micron. As long as it is within the maximum allowable tolerance, its thickness or thinness does not affect the amount of oil injected at each single test point, but only the total amount of oil injected multiple times in a short time. And the common maintenance with the test bench is not measured out.

Nozzle spring adjusting gasket: adjust the size of the nozzle spring force (commonly known as nozzle needle valve opening pressure). The CRIN2 nozzle spring force is generally set as 34N, with the maximum allowable tolerance of 3N. Excessive spring force can cause fuel injection deviation, especially in idle stage.

Needle valve lift adjustment gasket (intermediate piece) : adjust the maximum displacement of the needle valve in the process of operation. The setting values vary with injector models, generally ranging from 200 to 350 microns, with a maximum allowable tolerance of 10 microns. The size of the needle valve lift primarily affects the amount of fuel injected at the full load point.