THROTTLE VALVE OPENING ANGLE CONTROL AND IDLE SPEED CONTROL
MULTIPORT FUEL SYSTEM (MFI)13A-39
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.
CompensationsContent
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.
Rotation 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.
Atmospheric pressure compensationAt high altitudes atmospheric pressure is less and
the intake air density is low. So, the target opening
angle is compensated based on atmospheric
pressure.
Engine coolant temperature compensationCompensation is made according to the engine
coolant temperature. The lower the engine coolant
temperature the greater the throttle valve opening
angle.
Electric load compensationThrottle 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 When transmission 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 functioningThrottle 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 fluid pressure compensationThrottle valve opening angle is compensated
according to power steering functioning. When
power steering oil pressure rises and power
steering pressure switch is ON, the throttle valve
opening angle is increased.
MIVEC (Mitsubishi Innovative Valve Timing Electronic Control System)
MULTIPORT FUEL SYSTEM (MFI)13A-40
MIVEC (Mitsubishi Innovative Valve Timing Electronic
Control System)
M2132023500212
MIVEC is the system which continuously varies and
controls the opening and closing timings of the intake
valve and the exhaust valve.
System Configuration Diagram
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.
•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.
AK604826AB
Crankshaft
position sensor
Manifold absolute
pressure sensor
Intake camshaft
position sensorECMSpool valve
To oil pan
To oil pan Oil pressureAdvance direction Spool valve movementRetard direction Intake engine oil control valve
Retard chamber
Advance chamber
Spring
Crankshaft
position sensor
Manifold absolute
pressure sensor
Exhaust camshaft
position sensorECMSpool valve
To oil pan
To oil pan Oil pressureRetard direction Spool valve movementAdvance direction Exhaust engine oil control valve
Advance chamber
Retard chamber
Spring
