ENGINE FUEL AND EMISSION CONTROL SYSTEM 6C-31
3
rd
piston deactivator
Generalities
The 3
rd
piston deactivator device is made up of and electro-valve
(1) which, using a shaft (2), keeps open the admission valve (3)
during the delivery stage to the 3
rd
piston.
The electro-valve (1) is worked by the electronic control unit
when the engine, turning at a regime superior to 4200 rpm, does
not increase power. The fuel discharged through admission valve
(-1/3 of the flow) joins high pressure pump admission fuel.
Electro-valve termistals in electronic control unit:
Pin A20/A21
NOTE:
The 3
rd
piston deactivator device cannot be manipulated
during service. In the event of breakdown, replace the
high pressure pump.
2
1
3
Pressure Regulator Valve
Generalities
Fitted in the pump and controlled by the electronic control unit,
this valve regulates the fuel pressure to the electro-injectors.
The pressure regulator is mainly composed of:
- a spherical stopper (2)
- a valve (1) drive shaft (3)
- a preload spring (6)
- a reel (5)
Once the solenoid is not stimulated, the delivery pressure
depends on the preload of the spring (6)
The modulation of the pressure is obtained by exciting, in PWM
(Pulse Width Modulation), the solenoid reel and closing the
regulation loop through feedback from the pressure sensor; the
PWM signal has a capacity of 1000 Hz and the duty-cycle can
be varied via software from 1 to 95%.
Solenoid terminals in the electronic control unit:
Pin A9/A20
NOTE:
The pressure regulator valve cannot be manipulated or
replaced during service. In the event of breakdown,
replace the high pressure pump together with the pressure
regulator valve.
1
2
3
4 5
6
7
PRESSURE REGULATOR VALVE
1.- Valve
2.- Spherical stopper
3.- Valve drive shaft
4.- Body
5.- Reel
6.- Preload spring
7.- Anchor
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