Nissan Murano: System / Intake Valve Timing Control

System Description

SYSTEM DIAGRAM

System Description

INTAKE VALVE TIMING CONTROL

System Description

This mechanism hydraulically controls cam phases continuously with the fixed operating angle of the intake valve.

The ECM receives signals such as crankshaft position, camshaft position, engine speed, and engine coolant temperature. Then, the ECM sends ON/OFF pulse duty signals to the intake valve timing (IVT) control solenoid valve depending on driving status. This makes it possible to control the shut/open timing of the intake valve to increase engine torque in low/mid speed range and output in high-speed range.

INTAKE VALVE TIMING INTERMEDIATE LOCK CONTROL

System Diagram

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 pins and bringing the cam phase into intermediate phase.

Cam phase is fixed at the intermediate phase by two lock pins 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 pin and locking/unlocking the lock pin.

Lock/Unlock Activation

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 pin 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°C (140°F), ECM turns OFF the solenoid valve and starts normal intake valve timing control.