MITSUBISHI LANCER EVOLUTION X 2008 Manual PDF

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 CONTROL17-11
POSITIVE CRANKCASE VENTILATION (PCV)
VA LV E
PCV valve lifts the plunger according to negative pressure in
the intake manifold to create appropriate ventilation for the
crankcase.
EVAPORATIVE EMISSION CONTROL SYSTEMM2171000200147
HC (hydrocarbon) generated in the fuel tank are
adsorbed by the active carbon in the canister and
stored. HC stored in the canister is introduced to the
intake manifold when engine is in operation where it
is mixed with intake air and combusted. ECM intro
-
duces optimum HC amount according to driving con-
ditions and so performs duty control on the
evaporative emission purge solenoid. Also, the evap
-
orative emission purge solenoid is closed during
deceleration or immediately after engine start to
restrict change in air-fuel ratio and prevent engine
from stalling.
AK602324AC
Plunger
From
rocker
coverTo intake
manifold
Spring
AK604143
Evaporative emission
purge solenoid
Mass airflow sensor
ECM Intake air temperature sensor
Manifold absolute pressure
sensor
Engine coolant temperature
sensor
Throttle position sensor
Crankshaft position sensorEvaporative emission
canister
AB
MFI relay
Battery

EMISSION CONTROL
ENGINE AND EMISSION CONTROL17-12
EVAPORATIVE EMISSION PURGE SOLENOID
An evaporative emission purge solenoid is installed in the
intake manifold.The evaporative emission purge solenoid con
-
trols the intake volume of fuel vapor gas from the canister. The
evaporative emission purge solenoid is a duty control type
solenoid valve. When current is not passing through the coil,
nipple A is kept airtight and fuel vapor gas cannot be sucked in.
When current passes through the coil, air can pass between
nipple A and B and fuel vapor gas is sucked in. ECM changes
the ON duty ratio according to engine's operating condition to
control the intake volume of fuel vapor gas.
EXHAUST GAS RECIRCULATION (EGR) SYSTEM M2171000300122
When the combustion gas temperature becomes
high, generation of the environment polluting NOx
(nitrogen oxides) increases rapidly. EGR system is
used to decrease the volume of NOx generated.
EGR system re-circulates exhaust gas inside the
intake manifold. It increases specific heat of the com
-
bustion gases and reduces combustion speed to lower the combustion temperature and reduce the
volume of NOx generated. ECM calculates the EGR
introduction volume according to engine operating
conditions and controls the EGR valve opening angle
at optimum. Also, immediately after the ignition
switch ON signal is input, it drives fully closed step
-
per motor and performs initialization.
AK604745AC
B To canister
To intake manifoldA
AK602245AD
12V
ONOFF
0V100 ms
Evaporative
emission
purge solenoidFrom MFI relay
ECM
AK502987AE
ECMMass airflow sensor
Intake air temperature sensor
Manifold absolute
pressure sensor
Engine coolant
temperature sensor
Throttle position sensor
Crankshaft position sensor BatteryEGR valve
(stepper motor)

EMISSION CONTROL
ENGINE AND EMISSION CONTROL17-13
EXHAUST GAS RECIRCULATION (EGR) VALVE
An EGR valve is installed in the EGR valve support.The EGR
valve controls EGR flow volume using the stepper motor
method and reduces exhaust gas (NOx) and fuel consumption.
The EGR valve drives the stepper motor based on the signal
from ECM. When stepper motor rotor turns in clockwise or
anti-clockwise direction, the shaft fitted with a rotor and a screw
expands and contracts and the movement of the shaft causes
the valve to go up and down. Thus, EGR path gap is controlled
minutely. The stepper motor turns 15
° per step. The stepper
motor turns forward or back only up to the angle dictated by the
number of pulse signals (number of steps) from the ECM. In
other words, increase and decrease of the EGR flow volume
depends on the number of signals (number of steps) from
ECM. ECM changes current flow to the 4 coils (A, B, C, D) in
the stepper motor in sequence according to the phase pattern
in the following chart in order to turn the stepper motor rotor.
Open valve changes phase in order of 0
→ 1 → 2 → 3 → 0. Close
valve changes phase in order of 3
→ 2 → 1 → 0 → 3.
Phase
numberStepper motor coil
Coil ACoil BCoil CCoil D
0ONOFFOFFON
1ONOFFONOFF
2OFFONONOFF
3OFFONOFFON
AK604144
Coil
Shaft
Valve Outlet
Inlet
Rotor
Magnet
AB
AK604145
From MFI relay
EGR valve
(stepper motor)
ECM Coil
ACoil
BCoil
CCoil
DFlow rate
Step
AB

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

NOTES

16-1
GROUP 16
ENGINE
ELECTRICAL
CONTENTS
STARTER MOTOR . . . . . . . . . . . . . .16-2
ALTERNATOR . . . . . . . . . . . . . . . . . .16-2
IGNITION COIL . . . . . . . . . . . . . . . . . .16-2
SPARK PLUG . . . . . . . . . . . . . . . . . . .16-3

STARTER MOTOR
ENGINE ELECTRICAL16-2
STARTER MOTORM2161002000160
The starter motor is a reduction drive planetary gear type.
ALTERNATORM2162001000126
The alternator is a battery detection type.
It uses a pulley with a one-way clutch.
IGNITION COILM2163001000174
The ignition coil is a plug-top type.
AK603841
AK603842
AK602597
Plug boots
Rain cover Coil
AC