This page has been translated with google translate, there may be errors in the stories.
Injector are available in various versions such as tap injector, hole injectors and one & two-stage injectors. In addition, there are two types of injection techniques, namely directly in the cylinder space and indirectly in the swirl chamber. The injector is a vital part for the operation of a diesel engine, but is one that requires very little maintenance.
Tap injector.
A tap injector is used in diesel engines with indirect injection and has an opening pressure between 100 and 135 bar. The tap injector has 1 injection opening and the injector needle is lifted at a certain diesel pressure.
The fuel is injected into a pre- or swirl chamber and in this space the diesel is mixed with air, creating a combustible mixture
Hole injector
A hole nozzle is used in diesel engines with direct injection and has several openings through which the diesel is pressed directly into the cylinder. The combustion chamber is located in the piston base and the arrangement of the injection openings is precisely tailored to the shape of the combustion chamber.
Due to this construction, the injector can only be placed in the cylinder head in one way.
The opening pressure of this atomizer is between 180 and 250 bar.
One- and two-stage injector.
Diesel engines with a direct injection have a relatively hard diesel knock, this has to do with the large increase in pressure in the cylinder due to the large amount of diesel that is injected in one go.
By making use of the so-called pre-injection, combustion is started gently, which reduces diesel knock a lot.
The injectors have 2 springs, namely a normal spring and a weak spring. Due to the weaker spring, the needle will be able to lift a little at a low pressure, thus initiating combustion.
The needle of the injector runs against a stop, which is trapped by a strong spring. The pressure will continue to rise to the normal opening pressure and the needle will open to its maximum at that point (the main injection).
