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1-M18
M108S, WSM
ENGINE
■
Injector Operation
W1017602
The injector controls injection through the fuel pressure in the control chamber. The TWV (Two-Way Valve)
executes leak control of the fuel in the control chamber to control the fuel pressure within the control chamber. The
TWV varies with the injector type.
1) Non-Injection
When the TWV (2) is not energized, the TWV (2) shuts off the leak passage (6) from the control chamber, so the
fuel pressure in the control chamber and the fuel pressure applied to the nozzle needle are both the same rail
pressure. The nozzle needle thus closes due to the difference between the pressure-bearing surface area of the
command piston (4) and the force of the nozzle spring, and fuel is not injected.
For this type, the control chamber outlet orifice (3) is closed directly by the force of the spring.
2) Injection
When TWV energization starts, the TWV valve is pulled up, opening the leak passage (6) from the control chamber.
When this leak passage (6) opens, the fuel in the control chamber leaks out and the pressure drops.
Because of the control chamber internal presusre drops, the pressure on the nozzle needle overcomes the force
pressing down, the nozzle needle is pushed up, and injection starts. When fuel leaks from the control chamber, the
flow quantity is restricted by the orifice, so the nozzle (5) opens gradually. The injection rate rises as the nozzle (5)
opens. As the current continues to apply to the TWV (2), the nozzle needle eventually reaches the maximum amount
of lift, which results in the maximum injection rate. Excess fuel is returned to the fuel tank through the path shown.
3) End of Injection
When TWV energization ends, the valve descends, closing the leak passage (6) from the control chamber. When
the leak passage (6) closes, the fuel pressure within the control chamber instantly returns to the rail pressure, the
nozzle (5) closes suddenly, and injection stops.
(1) Solenoid
(2) TWV (Two-Way Valve)
(3) Outlet Orifice
(4) Command Piston
(5) Nozzle
(6) Leak Passage
(7) Inlet Orifice
A : Non Injection
B : Injection
C : End of Injection
D : From Rail
E : To Fuel Tank
KiSC issued 06, 2007 A
Summary of Contents for M108S
Page 1: ...M108S WORKSHOP MANUAL TRACTOR KiSC issued 06 2007 A...
Page 8: ...6 M108S WSM SAFETY INSTRUCTIONS KiSC issued 06 2007 A...
Page 9: ...7 M108S WSM SAFETY INSTRUCTIONS KiSC issued 06 2007 A...
Page 10: ...8 M108S WSM SAFETY INSTRUCTIONS KiSC issued 06 2007 A...
Page 11: ...9 M108S WSM SAFETY INSTRUCTIONS KiSC issued 06 2007 A...
Page 15: ...13 M108S WSM DIMENSIONS DIMENSIONS KiSC issued 06 2007 A...
Page 16: ...G GENERAL KiSC issued 06 2007 A...
Page 94: ...1 ENGINE KiSC issued 06 2007 A...
Page 189: ...2 CLUTCH KiSC issued 06 2007 A...
Page 218: ...3 TRANSMISSION KiSC issued 06 2007 A...
Page 295: ...4 REAR AXLE KiSC issued 06 2007 A...
Page 296: ...CONTENTS MECHANISM 1 STRUCTURE 4 M1 KiSC issued 06 2007 A...
Page 308: ...5 BRAKES KiSC issued 06 2007 A...
Page 333: ...6 FRONT AXLE KiSC issued 06 2007 A...
Page 334: ...CONTENTS MECHANISM 1 STRUCTURE 6 M1 1 4 WHEEL DRIVE TYPE 6 M1 KiSC issued 06 2007 A...
Page 359: ...7 STEERING KiSC issued 06 2007 A...
Page 360: ...CONTENTS MECHANISM 1 STRUCTURE 7 M1 1 STEERING MECHANISM 7 M1 KiSC issued 06 2007 A...
Page 376: ...8 HYDRAULIC SYSTEM KiSC issued 06 2007 A...
Page 406: ...9 ELECTRICAL SYSTEM KiSC issued 06 2007 A...
Page 463: ...10 CABIN KiSC issued 06 2007 A...