Mitsubishi Outlander XL. Manual — part 1260

System

Objective / Function

Composition parts

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.

Catalytic
converter

Decrease 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
<California>

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

CRANKCASE VENTILATION SYSTEM

M21701000004USA0000010000

ZK602752 AA00

Ventilation hose

Breather hose

Air cleaner

PCV valve

Flow of blow-by gas and clean air (low load area)

Flow of blow-by gas (high load area)

17c-4

EMISSION CONTROL

CRANKCASE VENTILATION SYSTEM

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 plenum. 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

crankcase. The blow-by gas in the crankcase is
induced to the intake manifold plenum through the
rocker cover and PCV valve. During high load driving,
blow-by gas in the crankcase is induced to the intake
manifold plenum 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.

POSITIVE CRANKCASE VENTILATION (PCV)

VALVE

ZK600307AA00

Spring

From
rocker
cover

To inlet
manifold
plenum

Plunger

PCV valve lifts the plunger according to negative pressure at the
intake manifold plenum to create appropriate ventilation for the
crankcase.

EVAPORATIVE EMISSION CONTROL SYSTEM

M21701000002USA0000010000

ZK602753

ECM

Evaporative
emission purge
solenoid

Evaporative
emission canister

MFI relay

Mass airflow sensor

Intake air temperature
sensor

Engine coolant
temperature sensor

Throttle position sensor

Crankshaft position sensor

Manifold absolute
pressure sensor

Battery

AA00

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

EMISSION CONTROL

17c-5

EVAPORATIVE EMISSION CONTROL SYSTEM

is mixed with intake air and combusted. ECM
introduces optimum HC amount according to driving
conditions and so performs duty control on the
evaporative emission purge solenoid. Also, the

evaporative emission purge solenoid is closed during
deceleration or immediately after engine start to
restrict change in air-fuel ratio and prevent engine
from stalling.

EVAPORATIVE EMISSION PURGE SOLENOID

ZK602524

A

B

To throttle body

To canister

AA00

An evaporative emission purge solenoid is installed in the intake
manifold.The evaporative emission purge solenoid controls 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.

ZK600276

12 V

ON

OFF

0 V

100 ms

AA01

Evaporative
emission
purge solenoid

ECM

From MFI relay

17c-6

EMISSION CONTROL

EVAPORATIVE EMISSION CONTROL SYSTEM

EXHAUST GAS RECIRCULATION (EGR) SYSTEM

M21701000003USA0000010000

ZK602754

ECM

Mass airflow sensor

Intake air temperature
sensor

Engine coolant
temperature sensor

Throttle position sensor

Crankshaft position sensor

Manifold absolute
pressure sensor

Battery

AA00

EGR valve
(stepper moter)

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 combustion
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 stepper motor and
performs initialization.

EMISSION CONTROL

17c-7

EXHAUST GAS RECIRCULATION (EGR) SYSTEM