Vtec/Vtc - Honda EP3 Service Manual

wEc/wc
The i-WEC has a VTC (Variable Valve Timing Control) mechanism on the intake camshaft in addition to the usual
VTEC.
This mechanism improves fuel efficiency and reduces exhaust emissions at all Ievels of engine speed, vehicle speed.
a n d e n g i n e l o a d .
The VTEC mechanism changes the valve lift and timing by using more than one cam profile.
The VTC changes the phase of the intake camshaft via oil pressure. lt changes the intake valve timing continuously.
HIGH
i
LOW <-
ENGINE SPEED
Drivino Condition VTC Control
D e s c r i D t i o n
Qr Light-load B a s e P o s i t i o n Cam angle is retarded to reduce the entry of exhaust
gas into the intake port and to achieve stable fuel
c o n s u m D t i o n d u r i n q l e a n b u r n .
?l M ed iu m/h ig h-load Advance Control
Cam angle is advanced for EGR effect and to reduce
this pumping loss. The intake valve is closed quickly
to help reduce the entry of airlfuel mixture into the
intake port and improve the charging effect.
€) High speed Advance-Base Position
C a m p h a s e a n g l e i s c o n t r o l l e d f o r o p t i m u m v a l v e
t i m i n q a n d m a x i m u m e n o i n e o o w e r .
{cont'd)
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