Suzuki DF200 Service Manual

ENGINE CONTROL SYSTEM 3-33
VVT (Variable Valve Timing) SYSTEM
• The VVT system is designed to continuously vary intake valve timing to best fit the engines current oper-
ating condition.
• The intake cam timing sprocket assembly (VVT actuator) is located at the front end of the intake cam-
shaft. The timing sprocket’ internal rotor is operated by engine oil pressure. Since the rotor and intake
camshaft are bolted together, the rotor and camshaft move together. Varying the intake valve timing is
accomplished by changing the intake camshaft phase angle relative to the intake cam timing sprocket
using pressurized engine oil applied to the rotor through an ECM controlled oil control valve.
• The oil control valve (OCV) directs engine oil pressure to the advance chamber or retard chamber inside
the intake cam timing sprocket assembly (VVT actuator). The oil control valve operates on a duty cycle
controlled by the ECM.
• The ECM determines the optimum valve timing (advance angle) under various operating conditions
based on engine speed, throttle opening and cylinder wall temperature. These input values are then
used to control the position of the oil control valve (OCV). The ECM also detects the actual advance angle
from the CMP sensor inputs to perform feedback control and accurately maintain the target advance
angle.
Valve overlap
Ex. valve
Advance
40˚ movable angle
In. valve
Retard
Crank angle
Throttle sensor
ECM
Drain
Advance
Retard
Oil
filter
Oil
pump
Target
advance
Actual valve
timing
Cylinder temp. sensor
MAP sensor
Throttle opening angle
Cylinder temp.
CMP sensor
Ex. camshaft
Crankshaft
CKP sensor
Duty
control
Oil control valve (OCV)
Rotation direction
VVT actuator
In.
camshaft
Oil pan
Engine oil pressure
Signal
Crank
position
Feed
back
Cam position
Manifold pressure
Valve lift
ECM
OCV
+12 V
30
46
In. camshaft

Suzuki DF200 Specifications

General

Brand	Suzuki
Model	DF200
Category	Outboard Motor
Language	English