FUEL SYSTEM
Fuel Injection Pump / Governor / Timer
6-12 6LY3 Service Manual
© 2007 Yanmar Marine International
Timer Functions
The electro-hydraulic timer advances or retards the
fuel injection timing according to the timer phase
control calculation by the ECU. The ECU calculates
the optimum fuel injection timing depending on
engine speed, load and coolant temperature.
The engine oil is fed to the electromagnetic valve
(timer solenoid), which controls the advance oil
passage, retard oil passage and engine oil inlet /
outlet according to ECU indications.
When advancing, the timer solenoid opens the
advance port to the oil inlet side and opens the
retard port to the oil outlet side. The advance
chamber is pressurized with oil and the oil in the
retard oil chamber (Figure 6-7, (5)) is pumped out
through the engine oil outlet (Figure 6-7, (9)). Then
the timer piston moves as a result of oil differential
pressure and rotates to the advance direction by
the helical spline. The opposite occurs in the
reverse.
Figure 6-7
Figure 6-7
1 – Electromagnetic Valve
2 – Advance Oil Passage
3 – Retard Oil Passage
4 – Helical Spline
5 – Retard Oil Chamber
6–Piston
7 – Advance Oil Chamber
8 – Pump Camshaft
9 – Engine Oil Outlet
(1)
(9)
(4)
(6)
(8)
(2)
(7)
(3)
(5)
0005670
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