2013 SSANGYONG KORANDO coolant temperature

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Electric fan
Circulates the fresh air forcibly to exchange heat
with the radiator core fin.
Coolant temperature sensor
Measures the coolant
temperature and sends the
result to the engine ECU.
Radiator
Releases heat through fins and cools down the hot coolant as the
coolant passes through the tube of the radiator core.

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1. OVERVIEW
The pre-heating system for D20DTF engine has the glow plug to the cylinder head (combustion
chamber), and improves the cold start performance and reduces the emission level.
The pre-heating resistor (air heater) is used to heat the intake air.
This enables the diesel fuel to be ignited in low temperature condition.
The ECU receives the information such as, engine rpm, coolant temperature, engine torque, etc.,
through CAN communication during pre-heating process; and the pre-heating control unit controls the
pre-heating, heating during cranking and post-heating by the PWM control.
Glow plugGlow plug control unit
(GCU)
Glow indicatorEngine ECU (D20DTF)

4) System Operation
Glow plug is installed in the cylinder head. It enhances the cold starting performance and reduces the
exhaust gas during cold starting.
ECU receives the various signals such as engine rpm, coolant temperature and vehicle speed through
CAN communication lines. GCU controls the pre-heating, cranking and post-heating operations and
monitors the glow plug. If GCU detects a problem, it sends the result to ECU.
(2) Operation of AQGS
Duty control area:
Between 5 and 100%
Frequency: 20 Hz1.
2.
3.
(1) Characteristics of temperature and current in AQGS
FET (similar to transistor) for each cylinder in AQGS unit pre-heats the glow plug.
If the glow plug temperature reaches to target temperature, the temperature is controlled by
duty ratio. 1.
2.
3.
AQGS PWM ControlActual voltage pattern
AQGS unit supplies the power to glow plug. This shows the voltage and time
supplied by AQGS by steps. As shown
on the graph, the supplied voltage is
decreased as the steps are continued.
The 3rd step is to keep the temperature,
not to raise it.
Frequency: 20~33Hz
PWM Control duty ratio
- 1st step: 100%
- 2nd step: 35%
- 3rd step: 23%

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2) Location and Components
HFM sensor
Used as a main map value to control the EGR.
The coolant temperature, engine rpm, engine
load, intake air temperature (HFM: decreased at
(atmospheric pressure sensor: altitude
compensation) are used as auxiliary map values.
EGR pipe
Transports the exhaust gas from the EGR cooler
and EGR bypass valve to the intake duct.
E-EGR cooler and bypass valve
The cooler lowers the high temperature of the
exhaust gas and the bypass valve directly
supplies the exhaust gas to the intake duct
without passing through the EGR cooler to
reduce the emission of exhaust gas before
warming up the engine.
E-EGR valve
Receives the electric signal from the ECU to
control the valve.
EGR cooler
EGR bypass

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2) Input/Output Devices
3) Control Logic
The EGR system controls the EGR amount based on the map values shown below:
Main map value: Intake air volume
Auxiliary map value:
Compensation by the coolant temperature
Compensation by the atmospheric pressure: Altitude compensation
Compensation by the boost pressure deviation (the difference between the requested value and the
measured value of boost pressure)
Compensation by the engine load: During sudden acceleration
Compensation by the intake air temperature -
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The engine ECU calculates the EGR amount by adding main map value (intake air volume) and auxiliary
map value and directly drives the solenoid valve in the E-EGR to regulate the opening extent of the EGR
valve and sends the feedback to the potentiometer.
(1) Operating conditions
Atmospheric pressure: 0.92 bar or more
When there is no fault code related to EGR -
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(2) Shut off conditions
Abrupt acceleration: with engine speed of 2600 rpm or more
When the engine is idling for more than 1 minute
Vehicle speed: 100 km/h or more
Engine torque: 380 Nm or more -
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1. ENGINE DATA LIST
Data Unit Value
Coolant temperature
Intake air temperature
temperature or engine mode)
Idle speed rpmA/T
M/T
Engine load % 18~25%
Mass air flow kg/h 16 to 25 kg/h
Throttle position angle
Engine torque Nm varies by engine conditions
Injection time ms 3 to 5ms
Battery voltage V 13.5 V to 14.1 V
Accelerator pedal position 1 V 04. to 4.8V
Accelerator pedal position 2 V 0.2 to 2.4 V
Throttle position 1 V 0.3 to 4.6 V
Throttle position 2 V 0.3 to 4.6 V
Oxygen sensor mV 0 to 5 V
A/C compressor switch 1=ON / 0=OFF -
Full load 1=ON / 0=OFF -
Gear selection (A/T) 1=ON / 0=OFF -
Knocking control 1=ON / 0=OFF -
Brake switch 1=ON / 0=OFF -
Cruise control 1=ON / 0=OFF -

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Coolant temp. sensor
HFM (air
mass/temperature)
Fuel temp. sensorDifferential pres.
sensorD20DTF ECU
IMV
E-EGR
bypass valve
E-EGR valve
Fuel rail pres. sensor
GCU (Glow plug
control unit)

(2) Fuel Control
a. Fuel Pressure Control Elements
Pressure control consists of 2 principles.
Determines rail pressure according to engine operating conditions.
Controls IMV to make the rail pressure to reach to the required value. -
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Pressure in the fuel rail is determined according to engine speed and load on the engine.
When engine speed and load are high
The degree of turbulence is very great and the fuel can be injected at very high pressure in order to
optimize combustion.
When engine speed and load are low
The degree of turbulence is low. If injection pressure is too high, the nozzle's penetration will be
excessive and part of the fuel will be sprayed directly onto the sides of the cylinder, causing
incomplete combustion. So there occurs smoke and damages engine durability. -
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Fuel pressure is corrected according to air temperature, coolant temperature and atmospheric pressure
and to take account of the added ignition time caused by cold running or by high altitude driving. A
special pressure demand is necessary in order to obtain the additional flow required during starts. This
demand is determined according to injected fuel and coolant temperature.
b. Fuel Pressure Control
Open loop determines the current which needs to be sent to the actuator in order to obtain the flow
demanded by the ECU.
Closed loop will correct the current value depending on the difference between the pressure demand
and the pressure measured.
If the pressure is lower than the demand, current is reduced so that the fuel sent to the high pressure
pump is increased.
If the pressure is higher than the demand, current is increased so that the fuel sent to the high
pressure pump is reduced. -
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Rail pressure is controlled by closed loop regulation of IMV.