Mitsubishi Outlander XL. Manual - part 1247

Compensations

Content

Fuel injection compensation

Compensation  is  made  according  to  the  pressure
difference  between  atmospheric  pressure  and
manifold  absolute  pressure.  The  greater  the
difference in pressure, the shorter the injector drive
time.

Battery voltage compensation

Compensation  is  made  depending  on  battery
voltage. The lower the battery voltage, the greater
the injector drive signal time.

Learning value for fuel compensation

Compensation  amount  is  learned  to  compensate
feedback  of  heated  oxygen  sensor.  This  allows
system  to  compensate  in  accordance  with  engine
characteristics.

[Fuel limit control during deceleration]
ECM limits fuel when decelerating downhill to prevent excessive
rise  of  catalytic  converter  temperature  and  to  improve  fuel
efficiency.

[Fuel-cut control when over-run]
When engine speed exceeds a prescribed limit (7,500 r/min),
ECM cuts fuel supply to prevent overrunning and thus protect
the  engine.  Also,  if  engine  speed  exceeds  4,000  r/min  for  15
seconds while vehicle is stationary (no load), it cuts fuel supply
to protect the engine.

IGNITION TIMING AND CONTROL FOR CURRENT CARRYING TIME

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Ignition timing is pre-set according to engine driving
conditions.  Compensations  are  made  according  to
pre-set  values  depending  on  conditions  such  as
engine  coolant  temperature,  battery  voltage  etc.  to

decide  optimum  ignition  timing.  Primary  current
connect/disconnect  signal  is  sent  to  the  power
transistor to control ignition timing. Ignition is done in
sequence of cylinders 1, 2, 3, 4, 5, 6.

13A-36

MULTIPORT FUEL SYSTEM (MFI)

IGNITION TIMING AND CONTROL FOR CURRENT CARRYING TIME

System Configuration Diagram

ZK600291

1

2

3

4

5

6

AA01

Manifold absolute
pressure sensor

Mass airflow sensor

ECM

Ignition
coils

Ignition switch-IG

Battery

Spark plugs

Cylinder No.

Intake air temperature
sensor

Knock sensor

Crankshaft position
sensor

Camshaft position
sensor

Ignition switch-ST

Inhibitor switch (CAN)

Engine coolant
temperature sensor

1. Ignition power control

Based on the crankshaft position sensor signal and camshaft
position  sensor  signal,  ECM  decides  the  ignition  cylinder,
calculates the ignition timing and sends the ignition coil primary
current connect/disconnect signal to the power transistor of each
cylinder in the ignition sequence.

 

MULTIPORT FUEL SYSTEM (MFI)

13A-37

IGNITION TIMING AND CONTROL FOR CURRENT CARRYING TIME

ZK600292

<No.6TDC>

<No.6TDC>

<No.1TDC>

<No.2TDC>

<No.3TDC>

<No.4TDC>

<No.5TDC>

Camshaft position
sensor signal

H
L

H
L

Cylinder Stroke

No.1 cylinder

No.2 cylinder

No.3 cylinder

No.4 cylinder

No.5 cylinder

No.6 cylinder

Intake

Intake

Intake

Intake

Intake

Intake

Ignition

Compression

Compression

Compression

Compression

Compression

Compression

Combustion

Combustion

Combustion

Combustion

Combustion

Combustion

Exhaust

Exhaust

Exhaust

Exhaust

Exhaust

Exhaust

Exhaust

AA01

Crankshaft position
sensor signal

2. Spark-advance control and current carrying

time control

[During start]
ECM  initiates  ignition  at  fixed  ignition  timing  (5°  BTDC)
synchronized with the crankshaft position sensor signal.

[During normal operation]
After determining the basic spark-advance based on the intake
air  volume  and  engine  speed,  ECM  makes  compensations
based  on  input  from  various  sensors  to  control  the  optimum
spark-advance and current carrying time.

List of main compensations for spark-advance control and current carrying time control

Compensations

Content

Intake air temperature compensation

Compensation  is  made  according  to  intake  air
temperature. The higher the intake air temperature
the greater the delay in ignition timing.

Engine coolant temperature compensation

Compensation is made according to engine coolant
temperature.  The  lower  the  engine  coolant
temperature  the  greater  the  advance  in  ignition
timing.

Knocking compensation

Compensation is made according to generation of
knocking. The greater the knocking the greater the
delay in ignition timing.

13A-38

MULTIPORT FUEL SYSTEM (MFI)

IGNITION TIMING AND CONTROL FOR CURRENT CARRYING TIME

Compensations

Content

Stable idle compensation

Compensation is made according to change in idle
speed. In case engine speed becomes lower than
target speed, ignition timing is advanced.

Delay compensation when changing shift

During  change  of  shift,  sparking  is  delayed
compared to normal ignition timing to reduce engine
output  torque  and  absorb  the  shock  of  the  shift
change.

Battery voltage compensation

Compensation  is  made  depending  on  battery
voltage.  The  lower  the  battery  voltage  the  greater
the current carrying time and when battery voltage
is high current carrying time is shortened.

[Control for checking ignition timing]
During basic ignition timing set mode for M.U.T.-III actuator test
function, sparking is done with fixed ignition timing (5° BTDC)
synchronized with crankshaft position sensor signal.

THROTTLE VALVE OPENING ANGLE CONTROL AND IDLE SPEED CONTROL

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ECM  detects  the  amount  of  accelerator  pedal
depression (as per operator's intention) through the
accelerator pedal position sensor. Based on pre-set

basic  target  opening  angles  it  adds  various
compensations and controls the throttle valve opening
angle according to the target opening angle.

ZK600293AA01

Throttle
position
sensor

Main

Main

Sub

Sub

Motor drive circuit

A/C switch (CAN)

Engine coolant
temperature sensor

Intake air temperature
sensor

Crankshaft position sensor

Power steering fluid
pressure sensor

Generator FR terminal

Inhibitor switch (CAN)

Motor drive power supply
(From throttle actuator
control motor relay)

Throttle actuator
control motor

control unit

Barometric pressure
sensor

ECM

Accelerator
pedal position
sensor

MULTIPORT FUEL SYSTEM (MFI)

13A-39

THROTTLE VALVE OPENING ANGLE CONTROL AND IDLE SPEED CONTROL