Diesel Injector Fuel Injector 0445120197 Bosch for Man Ng 323 / Ng 363 / Nl 283 / Nl 323 / SL 363 / Su 320 / Su 360 Man D2066 Loh/Luh

Transient states analysis of CI engine injectors with the use of optical methods  (PART 4)

2 Research methodology

2.1. Test stand The research was conducted on the test bench in the Institute of Combustion Engines and Transport of Poznan University of Technology. This test bench consists of (its scheme is shown in figure 1): • A Constant Volume Chamber (CVC) for simulating in-cylinder conditions (back-pressure) typical for injection in internal combustion engine; air pressure range was kept up to 10 MPa; the chamber has optical access and two 500 W halogen lamps to illuminate fuel drops.

• A sequencer to generate control signals (5 V, TTL) for the injection system and the signals powering the diode; resolution of this device is ±1 ns.

 • A common rail stand for fuel supply; it consists of high pressure fuel pump Bosch CP 4.1, a control system to achieve fuel pressure in rail up to 200 MPa and another control unit to transform signals from the sequencer into proper electric signal for the injectors to start and finish the injection process.

• Current clamps (Chauvin Arnoux E3N with measuring resolution of 10 mV/A) and passive highimpedance oscilloscope probe M007 by Pico Technology. Both were used to measure electrical signals before the injector.

 • An acquisition system which consists of two main elements: the first one is AVL IndiModul to record electric signals (measured by the clamps and the probe) and control signals from the sequencer; the resolution of 500 kHz for signals during this test was selected; the other element is the high speed camera HSS5 by LaVision with recording speed of 250 kfps.

3.2. Test objects and measuring range For the tests the two common-rail injectors of different types were chosen. The first one was a piezoelectric injector by Bosch and the other one was of electromagnetic type, also by Bosch (their parameters are shown in table 1).