i-VTEC
  • The i-VTEC system has a variable valve timing control (VTC) mechanism on the intake camshaft in addition to the usual VTEC.
    This system improves fuel efficiency and reduces exhaust emissions at all levels of engine speed, vehicle speed, and engine load.
  • The VTEC system changes the intake valve lift and timing by using more than one cam profile.
  • KD model: The VTEC system pauses one side of the exhaust valves lift in addition to changing the intake valve lift and timing.
  • The VTC system changes the phase of the intake camshaft via oil pressure. It changes the intake valve timing continuously.
Driving Condition
VTC Control
Description
(1) Light-load
Base Position
For stable combustion the cam angle is retarded, and reduces the entry of exhaust gas into the cylinder.
(2) Medium/high-load
Advance Control
Cam phase angle is controlled to optimize valve timing, improving fuel efficiency and reducing emissions.
(3) High speed
Advance-Base Position
To reduce pumping loss, the intake valve is closed quickly. This gives the air/fuel mixture a charging effect that helps to maximize engine power.


VTC System

  • The VTC system makes continuous intake valve timing changes based on operating conditions.
  • Intake valve timing is optimized to allow the engine to produce maximum power.
  • Cam angle is advanced to obtain the EGR effect and reduce pumping loss. The intake valve is closed quickly to reduce the entry of the air/fuel mixture into the intake port and improve the charging effect.
  • The system reduces the cam advance at idle, stabilizes combustion, and reduces engine speed.
  • If a malfunction occurs, the VTC system control is disabled and the valve timing is fixed at the fully retarded position.