Test; Tightness Test - alfatest Multijet Pro Manual Del Usuario

MULTIJET PRO
Adjustable
Plugs
Injector
Diameter Reducer
Injector
Tip Limiter

4.0 - TEST

ELECTRICAL RESISTANCE TEST
Check the state of the injector actuation coil. It basically consists of measuring the coil resistance, which can reveal
the existence of short-circuit, impedances out of specification and burnt or open coils. To evaluate the test result, one
must know the injector model and its electrical specification, which can be obtained through the manufacturer or its
distributors.
IIn general, the injectors are low-impedance elements (electrical resistance between 1 and 15 ohms). However,
checking the resistance may not be enough, since it changes with temperature variation. It is possible for the injector
to pass in the resistance test at room temperature and fail when heated. If this occurs, it may be that the insulation
of the injector coil is compromised.
In multipoint systems, the resistance variation accepted between injectors is 10% (one in relation to the other).

TIGHTNESS TEST

Check the quality of the valve packing and the presence of leaks. This consists of subjecting the injector to a
pressure 20% higher than the working pressure for some seconds, however, without activating it. If there is
dripping, the injector may be dirty, the needle may be warped, there may be erosion in the seat of the needle or in
the needle valve itself or the assembly itself may be greatly worn out.
PULVERIZATION AND SPRAYING OF INJECTOR
The injectors are subjected to sufficient conditions to check their working condition (line pressure, opening time,
etc.). Therefore, it should be noted the type of pulverization expelled from the injector during the entire procedure.
Pulverization of the injected liquid may be observed through use of the Stroboscopic light or Backlighting. The
spraying angle must be symmetrical, uniform and homogeneous. The depth and opening angle must correspond to
the manufacturer specifications.
Discontinuities and asymmetrical jets indicate the presence of problems, which can originate in the cleaning or
erosion of the needle or of the liquid outlet ducts.
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