Suzuki Liana RH418, Supplementary Service Manual

Page: 130 / 371

1D-4 Engine Mechanical:
Timing retarding
When the duty ratio of the signal output from the ECM is
light, the spool valve of the oil control valve moves to the
right (head for the coil). By this spool valve movement,
the pressurized oil is led into the chambers for timing
retarding and the oil in the chambers for timing
advancing is drained. This operations actuate the rotor
and result in the retarded timing of the intake valve.
Targeted timing varying operation
I3RH0B140007-01
DRIVING CONDITION VALVE TIMING TARGET OF CONTROL EFFECT
Engine running at idle
speed Most retarded To shorten the valve opening overlap in
order to prevent the exhaust gas counter
flow to intake manifold. Stabilization of the
engine rotation at idle
speed.
Average engine load
range To the advanced side To lengthen the valve opening overlap in
order to enhance the internal exhaust gas
recirculation and reduce the pumping loss.
Improvement of the fuel
efficiency.
Lowering of the exhaust
emission.
Light engine load range To the retarded side To shorten the valve opening overlap in
order to prevent the exhaust gas counter
flow to intake manifold.
Keeping of the engine
stability.
Low or average engine
speed range with heavy
engine load To the advanced side To advance the closing timing of the intake
valve in order to improve the volumetric
efficiency.
Improvement of
generating the engine
torque at low and
average engine speed.
High engine speed
range with heavy engine
load To the retarded side To retard the closing timing of the intake
valve in order to improve the volumetric
efficiency.
Improvement of
generating the engine
power.
Low engine coolant
temperature Most retarded To shorten the valve opening overlap in
order to prevent the exhaust gas counter
flow to intake manifold and reduce the fuel
increasing.
To slow the fast idle speed of the engine as
a result of stabilizing the engine idling. Stabilization of the fast
idling of the engine.
Improvement of the fuel
efficiency.
At engine starting and
stopping Most retarded To shorten the valve opening overlap in
order to prevent the exhaust gas counter
flow to intake manifold. Improvement of start
ability