MIVEC (Mitsubishi Innovative Valve Timing Electronic Control System)

Engine-ECU turns the oil feeder control valve ON/OFF according to engine speed in order to control oil pressure acting on the piston in the rocker arm. Thus, change is done between low-speed cam and high-speed cam.
System Configuration Diagram

Engine-ECU turns OFF (Duty: 0 %) the oil feeder control valve at low engine speed (4,750 r/min or less). As a result, oil pressure does not act on the piston in the rocker arm and inlet valve is driven by the low speed cam. Engine-ECU turns ON (Duty: For 2 seconds after change 100 %; after 2 seconds 60 %) the oil feeder control valve at high engine speed (4,750 r/min or more). As a result, oil pressure acts on the piston in the rocker arm and inlet valve is driven by the high speed cam. It will be continually driven by the low speed cam under following conditions.

Engine coolant temperature is less than 20°C.
For 10 seconds after engine is fully started.

Driving condition	Valve timing	Action	Benefit
Low engine speed		Valve opening time is shortened to limit spit back volume by intake air.	Improvement of low speed torque
High engine speed		Valve opening time is increased to increase input air volume.	Improve output power