Mitsubishi Evolution X. Manual - part 128
MIVEC (Mitsubishi Innovative Valve Timing Electronic Control System)
TSB Revision
MULTIPORT FUEL SYSTEM (MFI)
13A-41
List of main compensations for throttle valve opening angle and idle speed control
Initialize control
After ignition switch turns OFF, ECM drives the throt-
tle valve from fully closed position to fully open posi-
tion and records the fully closed/open studied value
of the throttle position sensor (main and sub) output
signals. The recorded studied values are used as
studied value compensation for compensating basic
target opening angle when the engine is started next.
MIVEC (Mitsubishi Innovative Valve Timing Electronic
Control System)
M2132023500405
MIVEC is a control system continuously varying the
intake valve timing and exhaust valve timing. The
opening and closing period of the valve does not
change.
MIVEC allows the optimum valve timing to be con-
trolled in accordance with the engine operation and
the idling stability to be improved, as well as the out-
put and the torque to be better in all the operation
ranges.
Compensations
Content
Stable idle compensation (immediately after start)
In order to stabilize idle speed immediately after
start, target opening angle is kept big and then
gradually reduced. Compensation values are set
based on the engine coolant temperature.
Engine speed feedback compensation (while idling) In case there is a difference between the target idle
speed and actual engine speed, ECM
compensates the throttle valve opening angle
based on that difference.
Barometric pressure compensation
At high altitudes barometric pressure is less and
the intake air density is low. So, the target opening
angle is compensated based on barometric
pressure.
Engine coolant temperature compensation
Compensation is made according to the engine
coolant temperature. The lower the engine coolant
temperature the greater the throttle valve opening
angle.
Electric load compensation
Throttle valve opening angle is compensated
according to electric load. The greater the electric
load, the greater the throttle valve opening angle.
Compensation when shift is in D range <TC-SST> When shift lever is changed from P or N range to
some other range, throttle valve opening angle is
increased to prevent reduction in engine speed.
Compensation when A/C is functioning
Throttle valve opening angle is compensated
according to functioning of A/C compressor. While
A/C compressor is being driven, the throttle valve
opening angle is increased.
Power steering pressure compensation
Throttle valve opening angle is compensated
according to power steering functioning. When
power steering pressure rises and power steering
pressure switch is ON, the throttle valve opening
angle is increased.