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

M21302000050USA0000010000

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

M21302000035USA0000010000

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