Mitsubishi Outlander (2013+). Manual — part 40

FUEL INJECTION CONTROL

MULTIPOINT FUEL INJECTION (MPI)

13A-28

Fuel Injection Volume Control Block Diagram (Normal Operation)

[Injector basic drive time]

Fuel injection is performed once per cycle for each
cylinder. Basic drive time refers to fuel injection vol-
ume (injector drive time) to achieve theoretical
air-fuel ratio for the intake air volume of 1 cycle of 1
cylinder. Fuel injection volume changes according to

the pressure difference (injected fuel pressure)
between manifold pressure and fuel pressure (con-
stant). So, injected fuel pressure compensation is
made to injector drive time for theoretical air-fuel
ratio to arrive at basic drive time.

AK602278AB

Air flow sensor

Crank angle sensor

Oxygen sensor

Engine coolant
temperature
compensation

Engine coolant
temperature sensor

Manifold absolute
pressure sensor

Fuel pressure
compensation

Barometric pressure
sensor

Battery voltage
compensation

Battery voltage

Basic fuel
injection time
determination

Air fuel ratio
compensation
(Predetermined
compensation)

Oxygen sensor
feedback
compensation

Injector

Acceleration-
deceleration
compensation

AK602279AB

Basic fuel
injection time

Fuel injection pressure compensation

Intake air amount per cycle per cylinder

Theoretical air-fuel ratio

FUEL INJECTION CONTROL

MULTIPOINT FUEL INJECTION (MPI)

13A-29

Intake air volume of each cycle of 1 cylinder is calcu-
lated by engine-ECU based on the airflow sensor
signal and crank angle sensor signal. Also, during
engine start, the map value prescribed by the coolant
temperature sensor signal is used as basic drive
time.

[Injector drive time compensation]

After calculating the injector basic drive time, the
engine-ECU makes the following compensations to
control the optimum fuel injection volume according
to driving conditions.

List of main compensations for fuel injection control

[Fuel limit control during deceleration]

Engine-ECU limits fuel when decelerating downhill to
prevent excessive rise of catalytic converter temper-
ature and to improve fuel efficiency.

[Fuel-cut control when over-run]

When engine speed exceeds a prescribed limit
(6,600 r/min), engine-ECU cuts fuel supply to pre-
vent overrunning and thus protect the engine.

Compensations

Content

Oxygen sensor feedback compensation

The Oxygen sensor signal is used for making the
compensation to get air-fuel ratio with best cleaning
efficiency of the 3-way catalytic converter. This
compensation might not be made sometimes in
order to improve drivability, depending on driving
conditions. (Air-fuel ratio compensation is made.)
The engine-ECU compensates the output signal of
the oxygen sensor (front) using the output signal of
the oxygen sensor (rear). This allows the deviation
of the output signal, caused by the deterioration of
the oxygen sensor (front), to be solved, then the
highly accurate exhaust gas control is performed.

Air-fuel ratio compensation

Under driving conditions where oxygen sensor
feedback compensation is not performed,
compensation is made based on pre-set map
values that vary according to engine speed and
intake air volume.

Engine coolant temperature compensation

Compensation is made according to the engine
coolant temperature. The lower the engine coolant
temperature, the greater the fuel injection volume.

Acceleration/ Deceleration compensation

Compensation is made according to change in
intake air volume. During acceleration, fuel injection
volume is increased. Also, during deceleration, fuel
injection volume is decreased.

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 oxygen sensor. This allows system to
compensate in accordance with engine
characteristics.

IGNITION TIMING AND CONTROL FOR CURRENT CARRYING TIME

MULTIPOINT FUEL INJECTION (MPI)

13A-30

IGNITION TIMING AND CONTROL FOR CURRENT

CARRYING TIME

M2132027100573

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 con-
nect/disconnect signal is sent to the power transistor
to control ignition timing. Ignition is done in sequence
of cylinders 1, 3, 4, 2.

System Configuration Diagram

1. Ignition power control

Based on the crankshaft position sensor signal and
camshaft position sensor signal, engine-ECU
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.

AK502722

1

2

3

4

AN

Engine-
ECU

Air flow sensor

Intake air temperature sensor

Manifold absolute
pressure sensor

Engine coolant
temperature sensor

Inlet camshaft position sensor

Crank angle sensor

Throttle position sensor

Detonation sensor

Ignition switch-ST

Ignition coil

Battery

Spark plug

Cylinder No.

Engine control relay

IGNITION TIMING AND CONTROL FOR CURRENT CARRYING TIME

MULTIPOINT FUEL INJECTION (MPI)

13A-31

2. Spark-advance control and current car-
rying time control

[During start]

Engine-ECU 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, engine-ECU
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

AK604969

Exhaust

AC

Cylinder stroke

No. 1

Cylinder

No. 3

Cylinder

No. 4

Cylinder

No. 2

Cylinder

Combustion

Intake

Exhaust

Combustion

Compression

Ignition

Intake

Exhaust

Compression

Combustion

Intake

Compression

Intake

Exhaust

Combustion

Compression

H

L

H

L

Crank angle
sensor signal

Inlet camshaft
position sensor
signal

<No. 2 TDC>

<No.1 TDC>

<No. 3 TDC>

<No. 4 TDC>

<No. 2 TDC>

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.

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.