Page 15 - E BOOK ENGINE MECHANICAL M2

2. MIVEC ENGINES

(2) Variable Valve Timing (V.V.T.) Sprocket
The MIVEC actuator is built-in the V.V.T.
sprocket to vary the valve timing. The oil
feeder control valve controls the hydraulic
pressure from the oil pump, and depend-
ing on the port that it is fed through (either
advance or retard chambers), it causes to
move the vane rotor in the MIVEC actua-
tor.

Fig. 2-3
Exhaust cam phase variation Intake cam phase variation

Cam lift

Crank angle
Fig. 2-4

(3) Camshafts
Each camshaft is provided with an oil pas-
sage to guide the hydraulic pressure from
the oil feeder control valve to the V.V.T.
sprocket.
Integrated at the back of each camshaft
there is a detecting sensing cam used by
the cam position sensor so the engine-
ECU can identify the position of the cam-
shafts.

Fig. 2-5

(4) Oil Feeder Control Valve

The oil feeder control valves are installed on the side of
the cylinder head. The engine-ECU operates each valve
in a duty cycle. When the ECU applies a current to the
coil, it creates a magnetic field that moves the plunger
against spring tension. The plunger is connected to the
spool valve. The spool valve position changes with the
amount of current that is applied to the coil, and de-
pending on which port has opened, hydraulic pressure
from the oil pump is directed to the retard or advance
chambers of the V.V.T., to continually changes the in-
take/exhaust camshaft phase.

Fig. 2-6

2 - 3 Pub. No. PTAE1225