Bi-VANOS

Bi-VANOS Control (Variable Camshaft Adjustment)

Performance, torque, idle characteristics and exhaust emissions reduction are improved by Variable Camshaft Timing (Bi-VANOS). The VANOS units are mounted directly on the front of the camshafts and adjusts the timing of the Intake and Exhaust camshafts from retarded to advanced. The ECM controls the operation of the Bi-VANOS solenoids which regulates the oil pressure required to move the VANOS units. Engine RPM, load and temperature are used to determine Bi-VANOS activation.




The Bi-VANOS mechanical operation is dependent on engine oil pressure applied to position the VANOS units. When oil pressure is applied to the units (via ports in the camshafts regulated by the solenoids), the camshaft hubs are rotated in the drive sprockets changing the position which advances/retards the intake/exhaust camshafts timing. The Bi-VANOS system is "fully variable". When the ECM detects that the camshafts are in the optimum positions, the solenoids maintain oil pressure on the units to hold the camshaft timing.

The operation of the VANOS solenoids are monitored in accordance with the OBD II requirements for emission control. The ECM monitors the final stage output control and the signals from the Camshaft Position Sensors for Bi-VANOS operation.