F2B ENGINE 121 T RAKKER E URO 4/5 Print 603.93.641 Base q November 2006 Injector Phases Figure 247 60669 1. Fuel valve - 2. Plunger - 3. Fuel outlet - 4. Filling and backflow passage Filling phase During the filling phase the plunger (2) runs up to the top position. After passing the highest point of the cam, the rocker arm roller comes near the base ring of the cam. The fuel valve (1) is open and fuel can flow into the injector via the bottom passage (4) of the cylinder head. Filling continues until the plunger reaches its top limit. Figure 248 60670 1. Fuel valve - 2. Plunger - 3. Fuel outlet - 4.
Filling and backflow passage Begin of injection The injection phase begins when, at a certain point in the down phase of the plunger, the solenoid valve gets energized and the fuel valve (1) shuts. The moment delivery begins, appropriately calculated by the electronic control unit, depends on the working conditions of the engine. The cam continues with the rocker arm to push the plunger (2) and the injection phase continues as long as the fuel valve (1) stays shut.