During the compression stroke in a four-stroke diesel engine, air is compressed in
the engine cylinder. The pressure of the air is increased and its temperature is also
increased. The diesel fuel is injected at the end of the compression stroke and the fuel is
The fuel feed system ensures that the diesel oil is injected into the cylinders at the
correct time. It consists of a diesel tank, a feed pump, a filter, an injection pump, an
injector and connecting lines. Regular testing of the fuel injection system ensures that the
diesel pump works effectively. 

Testing is carried out by: 
(i) Calibration and 
(ii) Phasing 
The injector tester consists of a small tank, pump, pressure gauge and handle.
There is a separate bowl for receiving the fuel sprayed from the nozzle. The injector to
be tested is fitted in the injection testing equipment. A valve which is used to control the
fuel is first opened, and then the handle is pressed downward. The downward movement
of the handle causes the fuel to be sprayed through the injector. The reading in the
pressure gauge shows the atmospheric pressure. If this pressure is equal to the pressure
specified by the manufacturer, then the injector is a good one. If the pressure is either
more or less, the spring in the injector should be accordingly adjusted.
The injector consists of the nozzle, nozzle valve, spring and body. The fuel is
forced under pressure by the fuel injection pump. The fuel lifts the nozzle valve because
of the pressure, and then the fuel is sprayed through the nozzle hole. The nozzle valve is
returned to its seat by the spring. Some amount of oil which is not injected passes
through the nozzle valve and reaches the tank through the leak-off pipe.
Fuel Injection testing Equipment Mechanical Project
Fuel Injection testing Equipment Mechanical Project
The compressed or pressurized air is given to the input supply of this fuel injector
testing equipment. The inlet valve is opened and the inlet pressure is noted down. The
fuel tank contains the some amount of fuel to conduct the testing operation.
The outlet gate valve is opened and the outlet pressure is noted done with the help
of outlet pressure gauges. The fuel injector is fitted to the holder with the help of suitable
arrangement. The 12v power supply is given to the fuel injector coil. The coil gets
energized to open the nozzle hole so that the pressurized fuel sprayed by the injector
nozzle. That sprayed pressure is noted, this is compare to the company pressure
specification so that the injector is tested. Further development of this project is follows. 
Three tests are done on injector testing machine to test an injector.
1. Pressure test.
2. Leak-off test.
3. Spray test.
Pressure test:-
Clamp the injector on the tests and operate the test pump. Note the reading of the dial indicator at which the injector nozzle starts spraying. It gives pressure reading. It should be the same as recommended by the company. If, it is less, then tighten the adjusting screw. Repeat the process until the correct pressure reading is obtained. Finally, tighten the lock nut.
Leak-off test:-
Clamp the injector on the tester and build up the pressure about 150 kg/cm2 by operating the tester pump. Keep this pressure for about ten seconds. If the pressure drops, it shows that there is leakage in the injector. Check the nozzle seat and nozzle valve needle and nozzle body. Correct the seat and needle by grinding and lapping, and after that again do the leak-off test.
Spray test:-
Spray test is also done on the same injector-testing machine. While operating the tester pump, see carefully the spray. It should not be like a current of oil, or with drops splitting away, but it should be fully atomized.
  • Four Wheeler Diesel Engine Application
  • In Automobile Quality control unit
  • Two wheeler Application
  1. It requires simple maintenance cares
  2. The Diesal engine vehicles fuel injector can be easily checked.
  3. Checking and cleaning are easy, because of the main parts are screwed.
  4. Repairing is easy.
  5. Replacement of parts is easy.
  6. No Oil wastage.
1. Initial cost is required to install this testing equipment.
2. Compressed air is required to operate this system.
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