Technical Information

TECHNICAL INFORMATION

4G63 engine used in LANCER EVOLUTION IX adopts variable valve timing control (MIVEC). This system optimally controls the intake valve timing in accordance with the operation conditions of the engine, and improves the idling stability and the fuel economy as well as increases the power output and torque in all operating ranges.

SENSOR

INTAKE CAMSHAFT POSITION SENSOR




The intake camshaft position sensor which is a Hall element type is mounted on the cylinder head.

This sensor detects the actual position of the intake camshaft by using the camshaft position sensing cylinder and converts it into the pulse signal.

The ECM affects the feedback control of the oil feeder control valve by using this pulse signal.

ACTUATOR

OIL FEEDER CONTROL VALVE




The oil feeder control valve, which is a solenoid valve that operates under the duty cycle control, is mounted on the cylinder head. The duty cycle signals from the ECM make the spool valve in the oil feeder control valve move in order to control the hydraulic pressure in the V.V.T. (Variable Valve Timing) sprocket (intake camshaft sprocket).

The movement of the spool valve makes the engine oil from the cylinder block supplied to the advance chamber or the retard chamber at the V.V.T. sprocket, thus continuously the phase of the intake camshaft is changed.

The ECM controls the oil feeder control valve in accordance with the signals provided by the crankshaft position sensor and the volume airflow sensor.

MIVEC (MITSUBISHI INNOVATIVE VALVE TIMING ELECTRONIC CONTROL SYSTEM)
The intake camshaft sprocket (V.V.T. sprocket) and the camshaft are designed to slide, and the system regulates the volume of oil that is supplied to the oil chambers (for timing advance and retard), which are provided in the camshaft. Thus, the system varied the valve timing by controlling the phase angle (staggered angle) between the V.V.T. sprocket and the camshaft.

The phase angle between the V.V.T. sprocket and the camshaft is controlled by controlling the duty cycle of the current that is applied to the oil feeder control valve, which is provided in the cylinder head.

SYSTEM OPERATION




The ECM assesses the driving conditions by detecting the signals provided by various sensors, and sends duty cycle signals to the oil feeder control valve in accordance with the driving conditions, in order to control the position of the spool valve.

In the oil feeder control valve, the oil pressure is applied to the retard chamber or advance chamber, in order to continuously vary the phase of the intake camshaft.

When the engine is stopped, the ECM turns OFF the duty cycle signal, and applies a constant oil pressure to the retard chamber in order to hold the spool valve in the most retarded position.

The ECM detects the signal from the each sensor and calculates the optimized valve timing according to the operation, and then controls the oil feeder control valve.

In addition, the ECM detects the actual valve timing through the signal from the intake camshaft position senor and carries out the feedback control being closer the target valve timing.

Timing Advance




- The spool valve in the oil feeder control valve moves towards timing advance in accordance with the timing advance control signal from the ECM.
- The oil pressure from the cylinder block enters the advance chamber in the V.V.T. sprocket, and the vane rotor moves towards timing advance, thus causing the intake camshaft (which is coupled to the vane rotor) to advance.

Timing Retard




- The spool valve in the oil feeder control valve moves towards timing retard in accordance with the timing advance control signal from the ECM.
- The oil pressure from the cylinder block enters the retard chamber in the V.V.T. sprocket, and the vane rotor moves towards timing retard, thus causing the intake camshaft (which is coupled to the vane rotor) to retard.

Holding




- When the actual phase angle reaches the target phase angle, the advance chamber and the retard chamber hold their oil pressure in order to hold the phase angle of the intake camshaft.








Conceptual Diagram of Operation