Maintenance manual for sunray hfc4da1-2c china-IV diesel engines
94
is opened by solenoid valve. After the fuel drainage hole is closed, the hydraulic force applied onto the valve
controlled plunger (9) exceeds the pressure on the pressure shoulder of injector nozzle needle valve (11). Therefore,
the needle valve is pushed into the needle valve seat to block the high pressure passage to the combustion chamber.
When the solenoid valve of the fuel injector is actuated, the fuel drainage hole opens. In such case, the pressure in the
control chamber drops and thus the force applied onto the plunger reduces. Once the hydraulic pressure is less than the
force applied onto the pressure shoulder of the needle valve, the injector nozzle needle valve opens and the fuel injects
into the combustion chamber via the injection hole. The cause to indirectly control the injector nozzle needle valve by
hydraulic gain system is that the solenoid valve can’t directly generate the force required to rapidly open the needle
valve. The control amount required to open the injector nozzle needle valve is not included from the actual fuel
injection amount and is conveyed to the fuel return pipe through the fuel drainage hole of the control chamber.
Besides the control amount, the loss control fuel and the leak fuel at the injector nozzle needle valve and the valve
plunger chamber are conveyed to the fuel tank via the fuel return pipe and the fuel collection pipe connecting the
relief valve.
Depending on the working condition of the engine and the pressure generated by the high pressure fuel pump, the fuel
injector can be classified to 4 working conditions:
- Close of fuel injector (due to application of high pressure)
- Open of fuel injector (start of fuel injection)
- Full open of fuel injector
- Close of fuel injector (complete of fuel injection)
These working conditions are generated by means of the pressure distribution applied onto the fuel injector parts.
When the engine is stopped and there is no pressure in the common rail, the injector nozzle spring will close the fuel
injector.
Close of fuel injector (still state):
The solenoid valve is not actuated under still state and thus the fuel injector is closed (a). When the fuel drainage hole
is closed, the valve spring will press the ball vale of armature onto the fuel return orifice. The high pressure of
common rail is formed in the valve control chamber. Afterwards, a similar pressure is formed within the injector
nozzle chamber. The pressure applied onto the end face of control plunger by the rail pressure and the injector nozzle
spring force work together against the open force applied onto the conical pressure bearing face of needle valve by
fuel to maintain the needle valve at close state.
Open of fuel injector (start of fuel injection):
While the injector nozzle is at still state, the solenoid valve is actuated by the start current to ensure rapid open (b).
The force generated by the actuated solenoid valve overcomes the spring force so that the armature opens the fuel
drainage hole. Almost at the same time, the high start current drops to the low holding current required by the electric
magnet. This is possible as the air cap of the magnetic circuit becomes really small. When the ball valve of the fuel
drainage hole opens, the fuel flows from the valve control chamber to the empty chamber above and then returns to
the fuel tank via the fuel return pipe. The fuel drainage hole makes the pressure not completely balanced so that the
pressure in the valve control chamber drops. Therefore, the pressure in the valve control chamber is less than the
pressure of the fuel rail, which is still maintained in the fuel injector chamber, and the pressure drop in the valve
control chamber reduces the force applied onto the control plunger so that the injector nozzle needle valve opens and
the fuel injection starts.
The open speed of the injector nozzle needle valve depends on the flow difference between the fuel drainage hole and
the fuel inlet hole. The control plunger reaches its top dead center and then is held by one film of fuel, which is
formed by the fuel flow between the fuel drainage hole and the fuel inlet hole. In such case, the injector nozzle
completely opens and the fuel is injected into the combustion chamber at a pressure almost equaling to the fuel
pressure in the common rail. The pressure distribution in the injector nozzle is similar to that at the open stage.
Close of fuel injector (complete of fuel injection):
When the solenoid valve is no longer actuated, the valve spring pushes down the armature so that the ball of the valve
Summary of Contents for HFC4DA1-2C
Page 292: ...LT LT LT LT Lighting Lighting Lighting Lighting System System System System 84...
Page 341: ...SB SB SB SB Seat Seat Seat Seat Belt Belt Belt Belt 133 4 Remove the B pillar inner trim panel...
Page 355: ...GW GW GW GW Power Power Power Power Window Window Window Window 146...
Page 419: ...AT AT AT ATAir Air Air Air Conditioner Conditioner Conditioner Conditioner 210...
Page 424: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 213...
Page 425: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 214...
Page 428: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 217...
Page 429: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 218...
Page 430: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 219...
Page 431: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 220...
Page 432: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 221...
Page 433: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 222...
Page 434: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 223...
Page 435: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 224...
Page 436: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 225...
Page 437: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 226...
Page 438: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 227...
Page 439: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 228...
Page 440: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 229...
Page 441: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 230...
Page 442: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 231...
Page 443: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 232...
Page 444: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 233...
Page 445: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 234...
Page 446: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 235...
Page 447: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 236...
Page 448: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 237...
Page 449: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 238...
Page 450: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 239...
Page 451: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 240...
Page 452: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 241...
Page 453: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 242...
Page 454: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 243...
Page 455: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 244...
Page 456: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 245...
Page 457: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 246...
Page 458: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 247...
Page 459: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 248...
Page 460: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 249...
Page 461: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 250...
Page 463: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 252 Main harness 1...
Page 464: ...EC EC EC EC Circuit Circuit Circuit Circuit Diagram Diagram Diagram Diagram 253 Main harness 2...