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1. OVERVIEW
This system purifies the exhaust gas generated by the combustion in the engine to reduce the pollutants
and noise during that arise during combustion.
Harmful materials produced in the combustion process is treated and reduced in the exhaust system.
Harmful materials discharged from the crankcase and fuel tank is drawn into the intake system again to
reduce discharge amount of harmful materials.
Emission aftertreatment system ▶
Catalytic Converter & O2 Sensor
The catalytic converter is a monolith type purification system composed of cordierite which purifies
exhaust gas through the small holes of active monolith catalyst from the exhaust manifold. As exhaus
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gas passes through the small holes in the layer in the middle, its CO and HC are reduced by
oxidization reaction and its NOx is reduced by reduction reaction to Pt, Ph and Pd. The oxygen
sensor sends signals for feedback and determination of catalyst condition. For detailed description,
see the corresponding section. -
The fuel evaporative gas is a gas evaporated to the atmosphere in the section between the fuel tank and
fuel line, and its main component is hydrocarbon (HC). The fuel evaporative gas is temporarily stored in
the canister, and it is drawn to the engine through the throttle body when the purge control solenoid valve
is open according to the engine operating condition.
Gas in the combustion chamber is sealed by the piston. However, gas is leaked through the gap
between the cylinder and piston and drawn into the crankcase during the compression and explosion
strokes. This gas is blow-by gas and its main components are hydrocarbon and carbon monoxide. If this
gas is drawn into the crankcase, the system can be corroded and oil can be deteriorated. Also, if this
gas is discharged into the air, it can pollute the environment. To prevent these, the blow-by gas
reduction system (also called as crankcase ventilation system) draws the blow-by gas from the
crankcase to the combustion chamber for combustion.
Purge Canister Control ▶
Blow-by gas control system (crankcase ventilation system) ▶
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1. OVERVIEW
The ignition system is to supply high voltage generated from the ignition coil to the spark plug. The
G20DF engine is equipped with the independent type direct ignition system that the ignition coil is
installed in each cylinder.
The basic ignition timing in each cylinder is determined by the signals from camshaft position sensor and
crankshaft position sensor.
This ignition system controls the electronic ignition timing received from the engine ECU. To control the
ignition timing precisely, the ECU use the information below:
Engine load
Coolant temperature
Intake air temperature
Engine rpm
Camshaft position sensor (CPS)
Crankshaft position sensor (CKS) -
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If the signal from the camshaft position sensor is not delivered to the engine ECU, the ignition coil and
fuel system cannot be operated.
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5) ECO Cruise Control
The ECO cruise control system has nearly same functions with the auto cruise control system. It is an
automatic speed control system that maintains a desired driving speed without using the accelerator
pedal.
ECO cruise driving mode
The engine ECU controls the sharp acceleration and deceleration to improve the fuel economy.
The ECO cruise system is ready when pushing down the cruise control lever. At this moment, the
ECO indicator on the instrument cluster comes on.
The ECO cruise system operates when pulling up the cruise control lever.
To cancel the ECO cruise driving, push doen the cruise control lever. At this moment, the ECO
indicator on the instrument cluster goes off and the auto cruise starts to operate. -
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Control leverECO indicator
ON Blinking
Push down the lever O
Push down it again O
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3. ECU CONTROL
1) Functions
ECU receives and analyzes signals from various sensors and then modifies those signals into
permissible voltage levels and analyzes to control respective actuators.
ECU microprocessor calculates injection period and injection timing proper for engine piston speed and
crankshaft angle based on input data and stored specific map to control the engine power and emission
gas.
Output signal of the ECU microprocessor activates the injector solenoid valve to control the fuel injection
period and injection timing; so controls various actuators in response to engine changes.
Auxiliary function of ECU has adopted to reduce emission gas, improve fuel economy and enhance
safety, comforts and conveniences. For example, there are autocruise and immobilizer and adopted
CAN communication to exchange data among electrical systems (automatic T/M and brake system) in
the vehicle fluently. And the diagnostic tool can be used to diagnose vehicle status and defectives.
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47009b009600470052005f005c00b6006a004700880095008b> protected from factors like oil,
water and electromagnetism and there should be no mechanical shocks.
2) Control Functions
Controls by operating stages:
To make optimum combustion under every operating stage, ECU should calculate proper injection
volume in each stage by considering various factors.
Starting injection volume control:
During initial starting, injecting fuel volume will be calculated by function of temperature and engine
cranking speed. Starting injection continues from when the ignition switch is turned to ignition
position to till the engine reaches to allowable minimum speed.
Driving mode control:
If the vehicle runs normally, fuel injection volume will be calculated by accelerator pedal travel and
engine rpm and the drive map will be used to match the drivers inputs with optimum engine power. -
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(4) Features
Determines the ignition timing according to input signal
The ECU always analyzes the following elements when determining the ignition timing. 1.
Crankshaft position sensor
Camshaft position sensor
Coolant temperature sensor
Intake air temperature/air mass -
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Warm-up of catalytic converter
The ignition timing is retarded for about 20 seconds to operate the catalytic converter according to the
operating temperature under the following conditions: 2.
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The idle speed is increased by the idle speed control to help warming up of the catalytic converter -
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Idle speed control
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8b009d00880095008a008c008b0047009c00970047009b0096> 20˚ to help idle speed control.
The ignition timing control can be performed faster than the control through the throttle valve.
Fuel cut-off in deceleration
The ignition timing is retarded temporarily to prevent abrupt increase of the torque when the
combustion is restarted.
Intake air temperature/coolant temperature
The ignition timing is retarded to prevent knocking if the intake air temperature or coolant temperature
is high. The ignition timing is retarded in the following cases. 3.
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The intake air temperature is above 30°C.
The coolant temperature is above 105°C. -
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The ignition timing retard for intake air temperature and for coolant temperature is added up for
correction.
ESP/ASR control mode
The ignition timing is retarded to reduce engine torque as fast as possible under the ESP/ASR
control mode.
Knocking control
If knocking occurs in the cylinder, the ignition angle of the corresponding cylinder is retarded. The
coolant temperature is 15˚C to 40˚C when starting. 6.
7.
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(2) Warm-up Control Function
Low voltage ▶
If low voltage is detected by the ECU, the idle speed increases up to 100 rpm selectively under the
driving mode until the ignition switch is turned off. Idle speed control ▶
The idle speed is controlled according to the fuel/air mixture when the engine load is changed, the
power steering wheel is turned to its end, the selector lever is in the "D" position and the A/C compresso
r
is in operation. It is also controlled according to the charge level during the purge control operation.
Ignition timing ▶
The idle speed is controlled according to the fuel/air mixture when the engine load is changed, The
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8c008b0047009c00970047009b0096004700590057020b0047>to help idle speed control.
Air conditioner compressor operation ▶
The air conditioner control unit sends the air conditioner operation signal to the ECU to increase the
throttle valve opening amount in order to prevent reduction of the engine speed when the air conditioner
compressor is in operation at idling.
(3) Warm-up Control Operating Conditions
To make the catalytic converter reach a operating temperature, the ignition timing is retarded for about
20 seconds under the following conditions:
The coolant temperature is 15°C ~ 40°C when the engine is started.
The selector lever is in the "P" or "N" position. ▶
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Also, the idle speed increases to 1100 ~ 1500 rpm simultaneously by the idle speed control. However, as
soon as the selector lever is shifted to the D position, warming up control of the catalytic converter will be
inhibited. The information necessary to perform such control is as follows:
Coolant temperature
Engine rpm
Intake air mass
Recognizing idling status
Selector lever position ▶
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2. SPECIFICATION
DescriptionDiesel 2.0 Engine
(D20DTF(Low CO2))
General Overall length (mm) 4,410 (4,500: with trailer hitch)
Overall width (mm) 1,830
Overall height (mm) 1,675
Gross vehicle
weight (kg)M/T 4WD : 2,065(2,110)
2WD : 1,905(1,920)
Curb vehicle
weight (kg)M/T 4WD : 1,740(1,785)
2WD : 1,580(1,595)
Fuel Diesel
Fuel tank capacity (ℓ)57
Engine Engine D20DTF
Number of cylinders/ Compression ratio 4 / 16.5:1
Total displacement (cc) 1,998
Camshaft arrangement DOHC
Max. power M/T 149 ps / 4,000 rpm
Max. torque 360 Nm / 1,500~2,800 RPM
Idle speed750 ± 20 rpm
Cooling system Water-cooled / forced circulation
Coolant capacity (ℓ)8.5
Lubrication type Gear pump, forced circulation
Max. oil capacity (ℓ)6.0
Turbocharger and cooling type Turbocharger, water-cooled
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2. OPERATING PROCESS
System diagram ▶
Operation ▶
EEM monitors the electric loads and battery conditions and controls the voltage to improve the fuel
economy and battery charging efficiency.
EBS on “-“ terminal of battery sends the battery information (voltage, current, tem
perature and
SOC) to engine ECU with LIN communication.
Engine ECU outputs the information from EBS and regulating control signal (PWM) according to the
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9600990055>
Engine ECU controls the magnetic resistance between stator coil and rotor coil by controlling the
current in rotor coil according to PWM duty value.
The alternating voltage induced to stator coil is converted to direct voltage by rectifier. And, EBS
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9b008c009900950088009b009600990055> -
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