Renault Laguna III, Manual

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11A
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TOP AND FRONT OF ENGINE
Camshaft dephaser: Function
M4R
11A
I - SPECIAL NOTES
The camshaft dephaser modifies the valve timing.
To improve cylinder filling at all engine speeds, the en-
gine is fitted with an inlet camshaft dephaser (
1 ) .
Dephasing at the moment when the inlet valves close
optimises filling according to engine speed. Torque at
midrange engine speed and output at high engine
speed are improved.
Leaving the inlet valves open for longer at high engine
speed allows the mixture to be continually admitted
thanks to its high speed.
However, at lower engine speeds the gases do not
have a high level of inertia. It is therefore preferable to
close the inlet valves earlier to avoid incorrect filling
and a loss of torque due to the reflux of fresh gases.
The higher the engine speed, the later the inlet valves
must be closed.
II - OPERATION AND PROGRAMMING
The oil is supplied to the dephaser by a solenoid valve
(
2 ) located on the timing cover.
Supply by a variable opening cyclic ratio signal enables
oil to be distributed to the mechanism and the
dephaser angle to be adjusted.
The operation of the camshaft dephaser varies contin-
uously.
The computer supplies the solenoid valve with a vari-
able opening cyclic ratio proportional to the desired
dephasing.
The camshaft dephaser control solenoid valve is con-
trolled if the following conditions are met:
- no engine speed sensor fault
- no camshaft position sensor fault,
- no injection system faults,
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