Mitsubishi Evolution X. Manual - part 127

 

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Mitsubishi Evolution X. Manual - part 127

 

 

IGNITION TIMING AND CONTROL FOR CURRENT CARRYING TIME

TSB Revision

MULTIPORT FUEL SYSTEM (MFI)

13A-37

IGNITION TIMING AND CONTROL FOR CURRENT 

CARRYING TIME

M2132027100205

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

AK703692

1

2

3

4

AC

ECM

Mass airflow sensor

Intake air temperature
sensor 1

Engine coolant
temperature sensor

Intake camshaft position
sensor

Crankshaft position
sensor

Throttle position sensor

Knock sensor

Ignition switch-ST

Clutch pedal position switch 
<M/T>

Ignition coils

Battery

Spark plugs

Cylinder No.

MFI relay

: Coil driver

IGNITION TIMING AND CONTROL FOR CURRENT CARRYING TIME

TSB Revision

MULTIPORT FUEL SYSTEM (MFI)

13A-38

1. Ignition distribution control

Based on the crankshaft position sensor signal and intake cam-
shaft 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.

2. Spark-advance control and current carrying 
time control

.

[During start]

ECM initiates ignition at fixed ignition timing (5

° BTDC) syn-

chronized 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.

AK703693

<No. 2 TDC>

H

L

H

L

<No. 1 TDC>

<No. 3 TDC>

<No. 4 TDC>

<No. 2 TDC>

AC

Cylinder stroke

No.1

 cylinder

No.3

 cylinder

No.4

 cylinder

No.2

 cylinder

Combustion

Intake

Exhaust

Combustion

Exhaust

Compression

Intake

Exhaust

Compression

Combustion

Intake

Compression

Intake

Exhaust

Combustion

Compression

Intake camshaft
position sensor
signal

Crankshaft
position sensor
signal

Ignition

IGNITION TIMING AND CONTROL FOR CURRENT CARRYING TIME

TSB Revision

MULTIPORT FUEL SYSTEM (MFI)

13A-39

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

.

[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.

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.

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.

Delay compensation when depressing clutch pedal

During depression of clutch pedal, sparking is 
delayed compared to normal ignition timing to 
reduce engine speed.

THROTTLE VALVE OPENING ANGLE CONTROL AND IDLE SPEED CONTROL

TSB Revision

MULTIPORT FUEL SYSTEM (MFI)

13A-40

THROTTLE VALVE OPENING ANGLE CONTROL 

AND IDLE SPEED CONTROL

M2132003500500

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 compen-
sations and controls the throttle valve opening angle 
according to the target opening angle.

While starting

ECM adds various compensations to the target 
opening angle that are set based on the engine cool-
ant temperature, so that the air volume is optimum 
for starting.

While idling

ECM controls the throttle valve to achieve the target 
opening angle that are set based on the engine cool-
ant temperature. In this way best idle operation is 
achieved when engine is cold and when it is hot. 
Also, the following compensations ensure optimum 
control.

While driving

Compensations are made to the target opening 
angle set according to the accelerator pedal opening 
angle and engine speed to control the throttle valve 
opening angle.

AK702312AE

Throttle
position
sensor

Main

Main

Sub

Sub

Motor drive circuit

A/C switch (CAN)

Engine coolant temperature sensor

Intake air temperature sensor 1

Crankshaft position sensor

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

Control unit

Accelerator
pedal position
sensor

ECM

Throttle actuator
control motor

Mass airflow sensor

Barometric pressure sensor

Power steerling pressure switch

Generator FR terminal

Transmission range signal
(CAN) <TC-SST>

 

 

 

 

 

 

 

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