Mazda 2002 Millenia Spezifikationen PDF herunterladen (Seite 39)

VALVE MECHANISM

B31

Operation outline

• The variable valve timing actuator has two hydraulic chambers: a valve timing advance chamber and a valve

timing retard chamber. They are located between the integrated housing of the camshaft sprocket and the

camshaft integrated rotor. The oil pump supplies engine oil. to each chamber. Hydraulic pressure applied to

each chamber is controlled by the oil control valve (OCV) and the relative phases of the camshaft sprocket and

the camshaft are modified to obtain optimum valve timing according to engine operation conditions.

At engine start

• When the stopper pin in the variable valve timing actuator engages with the rotor, which is at the position of

maximum valve timing retard due to spring force, the camshaft sprocket and the camshaft rotate as one unit.

When the oil pump pressure rises and the stopper pin is disengaged, it becomes possible to modify the relative

angles of the camshaft sprocket and the camshaft.

Advancing valve timing

• When the spool valve in the oil control valve (OCV) moves to the left according to the PCM signal, hydraulic

pressure, from the oil pump, feeds into the valve timing advance passage and finally to the valve timing

advance chamber in the variable valve timing actuator. Then, the rotor integrated with the camshaft rotates in

the valve timing advance direction, against the housing driven by the crankshaft, and the valve timing is

advanced.

Retarding valve timing

• When the spool valve in the oil control valve (OCV) moves to the right according to the PCM signal, hydraulic

pressure, from the oil pump, feeds into the valve timing retard passage and finally to the valve timing retard

chamber in the variable valve timing actuator. Then, the rotor integrated with the camshaft rotates in the valve

timing retard direction, against the housing driven by the crankshaft, and valve timing is retarded.

AME2211N017

1PCM

2 Oil control valve (OCV)

3 Spool valve

4 Oil pump

5 Camshaft

6 Variable valve timing actuator

7Rotor

8 Housing

9Oil pan

10 To valve timing advance chamber

11 Valve timing advance chamber

12 From valve timing retard chamber

13 Hydraulic pressure flow

1 2 ... 34 35 36 37 38 39 40 41 42 43 44 ... 357 358

Keine Kommentare

Mazda 2002 Millenia Spezifikationen Seite 39