03-4
1. DESCRIPTION AND OPERATION
1) Exhaust System
When you are inspecting or replacing exhaust system components, make sure there is adequate
clearance from all points on the underbody to avoid possible
overheating of the floor panel and possible damage to the passenger compartment insulation
and trim materials.
Check the complete exhaust system and the nearby body areas and trunk lid for broken,
damaged, missing or mispositioned parts, open seams, holes, loose connections, or other
deterioration which could permit exhaust fumes to seep into the trunk may be an indication of a
problem in one of these areas. Any defects should be corrected immediately.
2) Catalytic Converter (Gasoline Engine)
When jacking or lifting the vehicle from the body side rails, be certain that the lift pads do not
contact the catalytic converter, as this could damage the catalytic converter.
Use of anything other than unleaded fuel will damage the catalyst in the catalytic converter. 1.
2.
Catalytic Converter Structure ▶
The Catalytic converter of monolith type consists
of 2 walled metal bodies which is made of
Cordierite. The principal element of converter
consists of the materials like Alumina or oxidized
Serume in order to apply to Ceramic Monolith.
Washer coat operates first, and catalytic metal
elements (Pt, Pd, Rh) operates to washer coat
next.
Monolith type is lighter than other types, easy to
manufacture and quickly approaches to proper
temperature. Washer coat is used to make a
contact surface with exhaust gas bigger by
adhering closely to small holes
of inner layer. If a lead compound or phosphorus
adheres to the surface and the temperature rises,
its surface is decreased. The total area of general
monolith converter is about 45, 000~500,000ft3.
(10 times of a football field) Generally
Alumina
(AL2 O3) is used as a raw materialand its 7
phases of gamma, delta, theta have big areas and
high stability for the temperature, and nowadays
gamma Alumina is used usually.
03-6
Method for Reduction of NOx ▶
NOx is generated a great deal in case that combustion temperature and excess air factor are
high. EGR valve can decrease NOx (30 to 35% decrease) by making temperature of combustion
chamber fall by means of exhaust gas re-circulation.
EGR valve is installed on the diesel engine of Musso, Korando, Istana and Rexton.
And micro switch is installed together to control EGR valve.
The setting method of micro switch is identical with the existing one. -
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04-6
2. DESCRIPTION AND OPERATION
1) General Description
The cooling system maintains the engine temperature at an efficient level during all engine
operating conditions.
When the engine is cold, the cooling system cools the engine slowly or not at all. This slow
cooling of the engine allows the engine to warm up quickly.
The cooling system includes a radiator and recovery subsystem, cooling fans, a thermostat and
housing, a water pump, and a water pump drive belt. The timing belt drives the water pump.
All components must function properly for the cooling system to operation. The water pump
draws the coolant from the radiator. The coolant then circulates through water jackets in the
engine block, the intake manifold, and the cylinder head. When the coolant reaches the operating
temperature of the thermostat, the thermostat opens. The coolant then goes back to the radiator
where it cools.
This system directs some coolant through the hoses to the heat core. This provides for heating
and defrosting.
The coolant reservoir is connected to the radiator to recover the coolant displaced by expansion
from the high temperatures. The coolant reservoir maintains the correct coolant level.
The cooling system for this vehicle has no radiator cap or filler neck. The coolant is added to the
cooling system through the coolant reservoir.
2) Radiator
This vehicle has a lightweight tube-and-fin aluminum radiator. Plastic tanks are mounted on the
upper and the lower sides of the radiator core.
On vehicles equipped with automatic transaxles, the transaxle fluid cooler lines run through the
radiator tank.
A radiator drain plug is on this radiator.
To drain the cooling system, open the drain plug.
3) Coolant Reservoir
The coolant reservoir is a transparent plastic reservoir, similar to the windshield washer reservoir.
The coolant reservoir is connected to the radiator by a hose and to the engine cooling system by
another hose.
As the vehicle is driven, the engine coolant heats and expands. The portion of the engine coolant
displaced by this expansion flows from the radiator and the engine into the coolant reservoir. The
air trapped in the radiator and the engine is degassed into the coolant reservoir.
When the engine stops, the engine coolant cools and contracts. The displaced engine coolant is
then drawn back into the radiator and the engine. This keeps the radiator filled with the coolant to
the desired level at all times and increases the cooling efficiency.
Maintain the coolant level between the MIN and MAX marks on the coolant reservoir when the
system is cold.
04-72112-01
4) Water Pump
The belt-driven centrifugal water pump consists of an impeller, a drive shaft, and a belt pulley.
The impeller is supported by a completely sealed bearing.
The water pump is serviced as an assembly and, therefore, cannot be disassembled.
5) Thermostat
A wax pellet-type thermostat controls the flow of the engine coolant through the engine cooling
system. The thermostat is mounted in the thermostat housing to the front of the cylinder head.
The thermostat stops the flow of the engine coolant from the engine to the radiator to provide
faster warm-up, and to regulate the coolant temperature. The thermostat remains closed while the
engine coolant is cold, preventing circulation of the engine coolant through the radiator. At this
point, the engine coolant is allowed to circulate only throughout the heater core to warm it quickly
and evenly.
As the engine warms, the thermostat opens. This allows the engine coolant to flow through the
radiator wherethe heat is dissipated. This opening and closing of the thermostat permits enough
engine coolant to enter the radiator to keep the engine within proper engine temperature operating
limits.
The wax pellet in the thermostat is hermetically sealed in a metal case. The wax element of the
thermostat expands when it is heated and contracts when it is cooled.
As the vehicle is driven and the engine warms, the engine coolant temperature increases. When
the engine coolant reaches a specified temperature, the wax pellet element in the thermostat
expands and exerts pressure against the metal case, forcing the valve open. This allows the
engine coolant to flow through the engine cooling system and cool the engine.
As the wax pellet cools, the contraction allows a spring to close the valve.
The thermostat begins to open at 82°C(180 °F) and is fully open at 95°C(203°F). The thermostat
closes at 80°C (176°F).
6) Electric Cooling Fan
Keep hands, tools, and clothing away from the engine cooling fans to help prevent personal
injury.
This fan is electric and can turn on even when the engine is not running. -
If a fan blade is bent or damaged in any way, no attempt should be made to repair or reuse
the damaged part. A bent or damaged fan assembly should always be replaced with a new
one to prevent possible injury. -
04-8
The cooling fans are mounted behind the radiator in the engine compartment. The electric cooling
fans increase the flow of air across the radiator fins and across the condenser on air conditioned
(A/C)-equipped vehicles.
This helps to speed cooling when the vehicle is at idle or moving at low speeds.
All models have two fans. The main fan is 320 mm (12. 6 inches) in diameter with seven blades to
aid the airflow through the radiator and the condenser. An electric motor attached to the radiator
support drives the fan.
The auxiliary fan is 320 mm (12.6 inches) in diameter.
A/C Off or Non-AC Model ▶
The cooling fans are actuated by the engine control module (ECM) using a low-speed
cooling fan relay, a high-speed cooling fan relay and a cooling fan motor relay.
The ECM will turn the cooling fans on at low speed when the coolant temperature reaches
95°C(203°F) and at high speed when the coolant temperature reaches 105°C(221°F).
The ECM will change the cooling fans from high peed to low speed at 100°C(212°F) and
will turn the cooling fans off at 90°C (194°F). -
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A/C On ▶
The ECM will turn the cooling fans on at low speed when the A/C system is on. The ECM
will change to high speed when the high side A/C pressure reaches 1860 kPa (269.8 psi).
The cooling fans will return to low speed when the high side A/C pressure reaches 1378
kPa (199.8 psi). -
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7) Engine Coolant Temperature Sensor
The Engine Coolant Temperature (ECT) sensor uses a temperature to control the signal voltage to
the Engine Control Module (ECM).
8) Coolant Temperature Gauge
The coolant temperature gauge controls the instrument panel temperature indicator. The coolant
temperature gauge is located with ECT sensor.
04-10
3) PWM Electric Fan
(1) Advantages and Disadvantages of the PWM Electric Fan
Advantages ▶
Enhanced A/C performance: at low speed,
at idling, driving in city
Reduction of vibration/noise: fan activated
by PWM only when necessary
Reduction of engine consuming power
(V/Fan driving force) by 4 Hp - Cost
saving -
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Disadvantage ▶
Poor engine cooling perfomance at low
and high rpm -
4) PWM (Pulse Width Modulation) Unit
It controls the time of the output voltage to
control the fan motor speed independently.
Internal functions ▶
Motor power shutting-off function when
overcurrent is applied
Adverse voltage prevention function
Detection function for the motor lock
Temperature detecting function: The
electric fan operates at FULL speed to
cool down the PWM unit when the interior
temperature of PWM unit is over
120~150°C.
Communication function when failing: The
fail signal is transmitted to the ECU when
the PWM unit is malfunctioning.
Soft start function: The motor speed is
gradually increased when the motor is
initially operated. -
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04-112112-01
5) Shutting-off Condition of the A/C Compressor
Coolant temperature ▶
When coolant temperature is below 20°C or over 115°C, engine speed is below 650 rpm or
over 4500 rpm for 4 seconds after engine starting, abrupt acceleration and A/C refrigerant
pressure sensor detecting the followings
A/C compressor is turned off when the refrigerant pressure is below 2.0 kg/cm2 and then
is turned on when the refrigerant pressure is over 2.4 kg/cm2.
A/C compressor is turned off when the refrigerant pressure is over 30 kg/cm2 and then is
turned on when the refrigerant pressure is below 21.4 kg/cm2. -
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05-51452-01
1. DESCRIPTION AND OPERATION
1) Battey
The sealed battery is standard on all cars. There are no vent plugs in the cover.
The battery is completely sealed, except for two small vent holes in the sides.
These vent holes allow the small amount of gas produced in the battery to escape.
The battery has the following advantages over conventional batteries:
No water addition for the life of the battery.
Overcharge protection. If too much voltage is applied to the battery, it will not accept as much
current as a conventional battery.
In a conventional battery, the excess voltage will still try to charge the battery, leading
to gassing, which causes liquid loss.
Not as liable to self-discharge as a conventional battery. This is particularly important when a
battery is left standing for long periods of time.
More power available in a lighter, smaller case. ·
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The battery has three major functions in the electrical system.
First, the battery provides a source of energy for cranking the engine.
Second, the battery acts as a voltage stabilizer for the electrical system. Finally, the battery
can, for a limited time, provide energy when the electrical demand exceeds the output of the
generator.
2) Ratings
<0068004700890088009b009b008c009900a00047008f0088009a0047009b009e0096004700990088009b00900095008e009a00610047004f005800500047008800470099008c009a008c0099009d008c0047008a008800970088008a0090009b00a0004700
990088009b00900095008e0047008b008c009a0090008e0095>ated at 27°C(80°F), which is the
time a fully charged battery will provide 25 amperes of current flow at or above 10.5 volts (2) a
cold cranking am
p rating determined under testing at -18°C(0°F), which indicates the cranking
load capacity. ▶
(1)Reserve Capacity
The reserve capacity (RC) is the maximum length of time it is possible to travel at night with the
minimum electrical load and no generator output. Expressed in minutes, the RC rating is the time
required for a fully charged battery, at a temperature of 27°C(80°F) and being discharged at a
current of 25 amperes, to reach a terminal voltage of 10.5 volts.