LR3/Disco 3
The piezo actuator (7) energized by the ECM extends (charging phase) and presses on the valve piston (9). The valve
mushroom (10) opens the bore, which connects the control chamber (11) to the fuel return (8 then 6).
As a result, the pressure in the control chamber drops, and the hydraulic force (4) acting on the tip of the nozzle needle is
now greater than the force (3) acting on the control piston in the control chamber.
The nozzle needle (13) moves upwards and the fuel passes through the six spray holes into the combustion chamber.
Engine Starting
During starting, the fuel rail pressure must be at least 150 bar. Should the pressure be below this figure, the injectors will
not operate, resulting in the vehicle not starting.
Engine Stopped
To stop the engine the ECM stops energising the piezo actuators, therefore, no fuel is injected and the engine speed
drops to zero.
3
-
Hydraulic force applied on control piston
4
-
Hydraulic force acting on tip of nozzle
5
-
Control piston
6
-
Fuel return
7
-
Piezo actuator
8
-
Fuel return
9
-
Valve piston
10
-
Valve mushroom
11
-
Control chamber
12
-
Control piston
13
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Nozzle needle
