Function Of Injector - wsm 03-CR-E4 Workshop Manual

MECHANISM
3. Fuel system

3.13.3 Function of injector

The injector injects high pressure fuel from the rail into the combustion chamber.
(1) Injection amount
(2) Top dead center (T. D. C.)
Injection is performed based on a signal received from the engine ECU indicating fuel injection timing and fuel
amount.
The injector injects fuel 3 times for one combustion.
The initial injection is called the pre-injection (a).
A small amount is injection during this injection reducing the effects of initial combustion and lowering NOx and noise.
The second injection is called the main injection (b), is used primarily for combustion and affects output. Therefore
this injection has the highest volume.
The 3rd injection is called the after injection (c) and combusts unburned fuel from combustion.
In addition to these injections, an injection called post injection (d) is performed during DPF regeneration.
This injection is not used to burn fuel in the combustion chamber but is used for raising the temperature of the DOC.
There are differences in amount injected between injectors and the ID codes are used to correct for these differences
information for correcting is input to the engine ECU.
Part
Two way electromag- Electromagnetic valve that is operated through turning current to a solenoid ON and OFF controlling flowing in and flow-
netic valve ing out of fuel from the rail to the control chamber.
This sets the raise and lower speed of the needle valve through constricting discharge and suctioning of fuel into the
Suction, discharge control chamber.
orifice Also, sets a slight delay between operation of the two way electromagnetic valve and operation of the needle valve ena-
bling reliable injection of very low amounts.
Valve piston Raises and lowers a nozzle needle through changing pressure in the control chamber provided on top of the piston.
Along with control chamber pressure causes the needle valve to be in close contact with the nozzle body preventing
Nozzle spring
leaking of high pressure fuel from the rail.
Part that performs fuel injection.
Nozzle The needle valve is raised and lowered based on change to pressure in the control chamber, opens and closes the fuel
injection port, and while the valve is open, atomizes and injects fuel from the rail.
03-CR-E4,03-CR-TE4BG
(3) Bottom dead center (B. D. C.)
(4) Crank angle
(a) Pre-injection
(b) Main injection
Function
4. ENGINE
(c) After injection
(d) Post injection
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KiSC issued 02, 2021 A