System Description
This engine is equipped with an intake valve timing controller (integral with cam sprocket) which continuously adjusts the phase of intake valve according to driving conditions, improves both low/mid range engine torque and high-speed range engine output, and brings about low emission and low fuel consumption.
The intake valve timing control system continuously controls cam phases in constant intake valve operating angle conditions and adjusts an operating oil pressure to the intake valve timing controller via the control solenoid valve.
ECM receives crankshaft position signal, camshaft position signal, engine speed signal, engine oil temperature signal, and engine coolant temperature signal. And the ECM outputs ON/OFF pulse duty signals to the intake valve timing control solenoid valve depending on driving status.
Intake Valve Timing Controller Operation List
| Intake valve timing solenoid valve condition | Intake valve timing controller operation |
|---|---|
| Engine OFF | When starting the engine, the controller vane and sprocket are fixed in full retard position by the reaction force of return spring, improving the starting performance of the engine. |
| Active (Advance angle) | When the energization rate to the control solenoid valve is increased, the oil pressure from the oil pump is conveyed to the advance angle chamber of the controller. And retard angle chamber oil is drained. Accordingly, the controller vane rotates rightward and the phase of camshaft becomes advance angle. This condition brings about the greater overlap with the exhaust valve, enabling the exhaust gas cleaning by the internal EGR effect and the fuel consumption improvement by the reduction in pumping loss. |
| Neutral (Maintained) | When it is the target valve timing, the energization rate to the control solenoid valve is adjusted to the intermediate state. The solenoid valve is positioned at the neutral position and the oil path is interrupted to maintain the cam shaft phase. |
| Return (Retard angle) | When the energization rate to the control solenoid valve is decreased, the oil pressure from the oil pump is conveyed to the retard chamber of the controller. And advanced angle changer oil is drained. Accordingly, the controller vane rotates leftward and the phase of camshaft becomes retard angle. |