6A2-6 ENGINE MECHANICAL (M13 ENGINE)
Oil control valve
The oil control valve switches and adjusts the hydraulic pressure
applied to the cam timing sprocket by moving the spool valve (1)
according to the duty pulse signals output from the ECM. By this
operation, the intake valve timing is varied continuously. Signals
output from the ECM are the duty pulse of about 240 Hz.
Cam timing sprocket
The cam timing sprocket is equipped with the chambers for timing
advancing (2) and retarding (3) which are separated by the rotor
(5). The rotor rotates receiving the hydraulic pressure applied to
both the chambers. The sprocket (1) is installed on the housing
(4) and the rotor is secured on the intake camshaft by fastening
the bolts. Therefore, the actuation of the rotor makes the phase
difference between the sprocket and intake camshaft.
Timing advancing
When the duty ratio of the signal output from the ECM is heavy,
the spool valve (4) of the oil control valve moves to the left (oppo-
site direction against the coil (5)). By this spool valve movement,
the pressurized oil (1) is led into the chambers for timing advanc-
ing and the oil in the chambers for timing retarding is drained.
This operations actuate the rotor (3) and result in the advanced
timing of the intake valve.
Timing holding
When the duty ratio of the signal output from the ECM shows that
of holding, the spool valve of the oil control valve is located at hold
position. Because this condition generates no oil pressure
changes in both chambers, the rotor is fixed at a target position.
1
6. Seal
1
2
3
4
5
6
2. Drain
12
5
4
3
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