Intake Valve Timing Intermediate Lock Control

System Diagram 

Courtesy of NISSAN NORTH AMERICA, INC.

System Description 

The intake valve timing intermediate lock control improves the cleaning ability of exhaust gas at cold starting by fixing the camshaft sprocket (INT) with two lock keys and bringing the cam phase into intermediate phase.

Courtesy of NISSAN NORTH AMERICA, INC.

Cam phase is fixed at the intermediate phase by two lock keys in the camshaft sprocket (INT).

ECM controls the intermediate phase lock by opening/closing the intake valve timing intermediate lock control solenoid valve to control oil pressure acting on the lock key and locking/unlocking the lock key.

Lock/Unlock Activation 

Courtesy of NISSAN NORTH AMERICA, INC.

When the ignition switch is turned OFF from the idle state, ECM activates the intake valve timing intermediate lock control solenoid valve to drain oil pressure. Accordingly, the lock key is activated by the spring, and the cam phase is fixed at the intermediate position.

When starting the engine by cold start, ECM activates the solenoid valve to maintain the condition that the cam phase is fixed at the intermediate position.

When the engine coolant temperature exceeds 60 deg.C (140 deg.F), ECM turns OFF the solenoid valve and starts normal intake valve timing control.