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.

Fig 1: Intake Valve Timing Diagram

Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig 2: Intake Valve Timing Graph

Courtesy of AMERICAN HONDA MOTOR CO., INC.