2008 MITSUBISHI LANCER EVOLUTION X catalytic converter

EMISSION CONTROL
ENGINE AND EMISSION CONTROL17-8
EMISSION CONTROL
GENERAL DESCRIPTIONM2171000101024
The following changes have been made to the con-
trols of the 2.4L engine provided on the GALANT.
SYSTEM CONFIGURATION DIAGRAM

Improvement / AdditionsRemark
Addition of HC trap catalytic converter HC decrease
AK604140
Positive crankcase
ventilation valve
Fuel pressure
regulator Evaporative emission
purge solenoid
Evaporative
emission
canisterEvaporative emission
ventilation valve
Fuel level
sensor
Fuel tank differential
pressure sensor
Fuel tank
temperature
sensor Fuel pump
Three-way catalytic converter Heated oxygen
sensor (front)
Heated oxygen
sensor (rear)Fuel tank
AB

EMISSION CONTROL
ENGINE AND EMISSION CONTROL17-9

Exhaust gas cleaning devices list
AK604141
Three-way catalytic converter Heated
oxygen
sensor
(front)
Heated
oxygen
sensor
(rear)
HC trap
catalytic
converterHeated oxygen sensor (3rd)Positive crankcase
ventilation valve
EGR valve
(stepper motor)
AB
Fuel level
sensorFuel
tank
Fuel tank differential
pressure sensor
Fuel tank
temperature
sensor Fuel pump Fuel pressure
regulator Evaporative emission
purge solenoid
Evaporative
emission
canisterEvaporative emission
ventilation valve
SystemObjective / FunctionComposition parts
Crankcase ventilation
systemHC decrease
Re-combustion of blow-by gas.
Positive crankcase ventilation
(PCV) valve
Evaporative emission
control systemHC decrease
Re-combustion of fuel vapor gas.
•Canister
•Evaporative emission purge
solenoid
Exhaust gas recirculation
(EGR) system
NOx decrease
Reduce NOx generation by controlling EGR
volume according to engine warm-up condition
and driving conditions.
EGR valve

EMISSION CONTROL
ENGINE AND EMISSION CONTROL17-10
CRANKCASE VENTILATION SYSTEMM2171000400129
A blow-by gas reduction device prevents blow-by
gas from being expelled into the atmosphere and is
of closed type. A positive crankcase ventilation
(PCV) valve is provided in the ventilation hose from
the rocker cover to the intake manifold. During low
load driving, clean air is supplied to the crankcase by
the air intake hose via the breather hose and rocker
cover, and it mixes with the blow-by gas in the crank
-
case. The blow-by gas in the crankcase is induced to
the intake manifold through the rocker cover and
PCV valve. During high load driving, blow-by gas in
the crankcase is induced to the intake manifold
through the rocker cover and PCV valve and at the
same time also via the air intake hose and throttle
body due to negative pressure in the air cleaner.
Emission
reduction
systemsAir-fuel ratio
feedback
controlDecrease of CO, HC and NOx
Controls air-fuel ratio of air-fuel mixture to
become theoretical air-fuel ratio (about 14.7),
which is when the 3-way catalytic converter's
cleaning performance is best. It also controls
optimum fuel supply based on coolant
temperature, driving conditions etc.
•ECM
•Mass airflow sensor
•Injectors
•Heated oxygen sensor
•Crankshaft position sensor
etc.
Catalytic
converterDecrease of CO, HC and NOx
It facilitates oxidation of CO and HC and
reduction of NOx so that all 3 component gases
are cleaned simultaneously.
Monolith catalyst
HC trap
catalytic
converter
HC decrease
During cold operation of engine, exhaust HC is
temporarily absorbed. And then Exhaust HC is
released when temperature reaches to level at
which catalyst is activated. This allows HC to be
reduced.
Monolith catalyst
System Objective / Function Composition parts
AK604142
Air cleaner
PCV valve
AB
Ventilation hose
Breather hose
Flow of blow-by gas and clean air (low load area)
Flow of blow-by gas (high load area)

EMISSION CONTROL
ENGINE AND EMISSION CONTROL17-14
EMISSION REDUCTION SYSTEMSM2171000800064
These decrease CO, HC and NOx in the exhaust
gases and consist of air-fuel ratio feedback control
and catalytic converter.
1. AIR-FUEL RATIO FEEDBACK CONTROL
Refer to GROUP 13A − Fuel Injection Control P.13A-29.
2. CATALYTIC CONVERTER
Catalytic converter is installed in the center of exhaust pipe
below the floor and in the front of exhaust pipe .
Based on appropriate air-fuel ratio feedback from oxygen sen
-
sor, CO and HC are oxidized and NOx is reduced. Catalytic
converter is a monolith with beehive design with catalysts on
the unit surface. It is protected by a thermally insulating mat
and enclosed in a shell.
3. HC TRAP CATALYTIC CONVERTER

The HC trap catalytic converter is installed in the center of
exhaust pipe below the floor. The HC trap catalytic converter
consists of the HC trap catalyst and the three-way catalysts,
which are the monolith type; the catalyst element is attached to
the honeycomb catalyst surface. The HC trap catalyst and the
three-way catalysts are held by the heat-insulating mat and
installed in the shell. The HC trap catalyst temporarily absorbs
the exhaust HC from the engine within the temperature range
in which the three-way catalyst is not activated, and prevents
the exhaust HC from releasing outside the vehicle. After that,
the HC trap catalyst temperature rises and releases the
absorbed HC. The released HC is burnt out in the downstream
three-way catalyst.
AK604146
Catalytic converter

Catalytic converter
AB
AK604147
Three-way catalyst HC trap catalyst
Exhaust
gas
AB

EMISSION CONTROL
ENGINE AND EMISSION CONTROL17-15
HEATED OXYGEN SENSOR (3RD)
The heated oxygen sensor (3rd) is installed to the HC trap cat-
alytic converter. The heated oxygen sensor (3rd) detects the
oxygen density of the exhaust gas and outputs the voltage to
the ECM in accordance with the oxygen density.
The ECM uses this output voltage to detect the deterioration of
the HC trap catalytic converter. The structure of the heated oxy
-
gen sensor (3rd) is the same as that of the heated oxygen sen-
sor (rear) installed in the exhaust pipe.
HC TRAP CATALYTIC CONVERTER
DETERIORATION MONITOR
The ECM detects the deterioration of the HC trap catalytic con-
verter.
When reaching the certain operating range, the ECM begins
monitoring the difference in the feedback time between the
heated oxygen sensor (rear) on the upstream of the HC trap
catalyst and the heated oxygen sensor (3rd) on the down
-
stream of the HC trap catalyst. This monitoring allows the ECM
to detect the deterioration of the HC trap catalytic converter.
AK604553
AB
Heated oxygen sensor (3rd)
HC trap catalytic converter
AK604148AB
Heated oxygen sensor (rear) Heated oxygen sensor (3rd)
ECMEngine coolant
temperature sensor
Accelerator pedal
position sensor
Crankshaft position sensor

13A-1
GROUP 13A
MULTIPORT FUEL
SYSTEM (MFI)
CONTENTS
GENERAL DESCRIPTION. . . . . . . . .13A-2
CONTROL UNIT. . . . . . . . . . . . . . . . .13A-6
SENSOR. . . . . . . . . . . . . . . . . . . . . . .13A-8
ACTUATOR . . . . . . . . . . . . . . . . . . . .13A-23
FUEL INJECTION CONTROL . . . . . .13A-29
IGNITION TIMING AND CONTROL FOR
CURRENT CARRYING TIME . . . . . .13A-35
THROTTLE VALVE OPENING ANGLE
CONTROL AND IDLE SPEED

CONTROL . . . . . . . . . . . . . . . . . . . . .13A-38
MIVEC (Mitsubishi Innovative Valve
Timing Electronic Control System) .13A-40
MULTIPORT FUEL INJECTION (MFI)
RELAY CONTROL . . . . . . . . . . . . . . .13A-45
FUEL PUMP RELAY CONTROL . . . .13A-46
STARTER RELAY CONTROL . . . . . .13A-47
HEATED OXYGEN SENSOR HEATER
CONTROL . . . . . . . . . . . . . . . . . . . . . .13A-49
A/C COMPRESSOR RELAY
CONTROL . . . . . . . . . . . . . . . . . . . . . .13A-50
GENERATOR CONTROL . . . . . . . . . .13A-51
EVAPORATIVE EMISSION CONTROL
SYSTEM INCORRECT PURGE FLOW
MONITOR . . . . . . . . . . . . . . . . . . . . . .13A-52
EXHAUST GAS RECIRCULATION
CONTROL . . . . . . . . . . . . . . . . . . . . . .13A-53
CONTROLLER AREA NETWORK
(CAN) . . . . . . . . . . . . . . . . . . . . . . . . .13A-53
EVAPORATIVE EMISSION PURGE
CONTROL . . . . . . . . . . . . . . . . . . . . . .13A-53
HC TRAP CATALYTIC CONVERTER
DETERIORATION MONITOR . . . . . . .13A-53
ON-BOARD DIAGNOSTICS . . . . . . . .13A-53

SENSOR
MULTIPORT FUEL SYSTEM (MFI)13A-14
.
HEATED OXYGEN SENSOR (except centor
exhaust pipe heated oxygen sensor )
Heated oxygen sensors are installed in 2 positions (front, rear)
on the catalytic converter. Heated oxygen sensor has a built-in
heater to help early activation of the sensor. This allows feed
-
back control of air-fuel ratio soon after engine start.
.
This sensor uses the oxygen concentration cell principle of
solid electrolyte (zirconia) and displays the property of sudden
change in output voltage near theoretical air-fuel ratio. This
property is used to detect oxygen density in exhaust gas. Feed
-
back to ECM allows it to judge whether air-fuel ratio is rich or
lean compared to theoretical air-fuel ratio.
AK602211
5V 5V
5
4
3
2
1
0
AE
Accelerator pedal position sensor
Accelerator pedal
position sensor (main)
Accelerator pedal
position sensor (main)
Accelerator
pedal stroke Accelerator pedal
position sensor (sub)
Accelerator pedal
position sensor (sub) Hall IC Hall IC
Fully
opened
Output voltage V
ECM
AK602572 AC
Sensing area
AK602262
AC
0.8
14 15 16Theoretical air fuel ratio Electro motive
force (V)
Rich Lean
Air fuel ratio

FUEL INJECTION CONTROL
MULTIPORT FUEL SYSTEM (MFI)13A-34
[Injector drive time compensation]
After calculating the injector basic drive time, the ECM makes
the following compensations to control the optimum fuel injec
-
tion volume according to driving conditions.
List of main compensations for fuel injection control
.
[Fuel limit control during deceleration]
ECM limits fuel when decelerating downhill to prevent exces-
sive rise of catalytic converter temperature and to improve fuel
efficiency.
.
[Fuel-cut control when over-run]
When engine speed exceeds a prescribed limit (6,600 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
and controls the throttle valve opening angle to protect the
engine.
CompensationsContent
Heated oxygen sensor feedback compensationThe heated 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.)
Air-fuel ratio compensationUnder driving conditions where heated 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 compensationCompensation is made according to the engine
coolant temperature. The lower the engine coolant
temperature, the greater the fuel injection volume.
Acceleration/ Deceleration compensationCompensation 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 compensationCompensation 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 compensationCompensation is made depending on battery
voltage. The lower the battery voltage, the greater
the injector drive signal time.
Learning value for fuel compensationCompensation amount is learned to compensate
feedback of heated oxygen sensor. This allows
system to compensate in accordance with engine
characteristics.