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.
MIVEC (Mitsubishi Innovative Valve Timing Electronic Control System)
TSB Revision
MULTIPORT FUEL SYSTEM (MFI)
13A-42
System Configuration Diagram
• The ECM assesses the engine operation through
the signals from each sensor.
• Based on the assessed information, the ECM
sends the duty signal to the intake engine oil con-
trol valve and exhaust engine oil control valve as
well as controls the spool valve position.
• Changing the spool valve position allows the oil
pressure to be divided into the retarded chamber
and the advanced chamber, as well as allows the
phases of the intake camshaft and the exhaust
camshaft to be continuously changed.
AK704678AB
Intake camshaft position
sensor
ECM
Spool valve
To oil pan
To oil pan
Oil pressure
Advance direction
Spool valve movement
Retard direction
Retard chamber
Advance chamber
Spring
Exhaust camshaft position
sensor
Spool valve
To oil pan
To oil pan
Oil pressure
Retard direction
Spool valve movement
Advance direction
Advance chamber
Retard chamber
Spring
ECM
Intake engine
oil control valve
Exhaust engine
oil control valve
Crankshaft position sensor
Crankshaft position sensor
Mass airflow sensor
Mass airflow sensor
Throttle position sensor
Throttle position sensor
Engine coolant temperature
sensor
Engine coolant temperature
sensor
MIVEC (Mitsubishi Innovative Valve Timing Electronic Control System)
TSB Revision
MULTIPORT FUEL SYSTEM (MFI)
13A-43
Phase Angle Detection
The detected phase angle is calculated using the
intake camshaft position sensor signal and the
exhaust camshaft position sensor signal.
Operation Conceptual Diagram
The ECM controls the camshaft phase angle in order
to attain optimal valve timing that suits the engine
load and engine speed.
AK703694
<No. 2 TDC>
H
L
H
L
<No. 1 TDC>
<No. 3 TDC>
<No. 4 TDC>
<No. 2 TDC>
H
L
AC
Intake camshaft
position sensor
signal
Exhaust camshaft
position sensor
signal
Crankshaft
position sensor
signal
: Phase angle
AK702315
Valve lift
Exhaust valve lift curve
(at most advanced
angle)
At most
retarded angle
Overlap
Crank angel
At most
advanced angle
Intake valve lift curve
(at most retarded angle)
Exhaust camshaft
phase angle
Intake camshaft
phase angle
AD
Initial phase
Control direction
Intake side
Most retarded angle
Advance direction
Exhaust side
Most advanced angle
Retard direction
INTAKE CHARGE PRESSURE CONTROL
TSB Revision
MULTIPORT FUEL SYSTEM (MFI)
13A-44
INTAKE CHARGE PRESSURE CONTROL
M2132026800085
The turbocharger wastegate solenoid operates
under duty cycle control in order to control the intake
charge pressure that acts on the turbocharger waste-
gate actuator. This results in a intake charge pres-
sure that suits the driving conditions of the engine.
.
The ECM turns the power transistor in the unit ON, causing the
turbocharger wastegate solenoid to fully open. This causes a
portion of the intake charge pressure acting on the turbo-
charger wastegate actuator to leak. Thus, unless the intake
charge pressure rises above the set pressure of the turbo-
charger wastegate actuator spring, the turbocharger wastegate
regulating valve will not open. On the other hand, when the tur-
bocharger wastegate solenoid is fully closed, there is no leak-
age of intake charge pressure. Therefore, when the intake
charge pressure rises to the set pressure of the turbocharger
wastegate actuator spring, the turbocharger wastegate regulat-
ing valve will open.
.
AK702865
ECM
AD
Crankshaft position sensor
Mass airflow sensor
Knock sensor
Engine coolant temperature
sensor
Air inlet
Bypass valve
Charge
air cooler
Turbocharger
Turbocharger
wastegate actuator
Turbocharger
wastegate solenoid 1
Turbocharger
wastegate solenoid 2
AK501259 AE
Actual
intake
charge
pressure
kPa (in. Hg)
Set
pressure
Solenoid in
"ON" position
Solenoid in
"OFF" position
Set pressure of spring
Intake charge pressure affecting turbocharger
wastegate actuator kPa (in. Hg)
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