Page 266 of 796

06-211914-01
Control
rangeTurbocharger
driving
mechanismControl
methodEffectImproved
performance
At low
speedNarrows the
flow passage fo
r
the exhaust gas
by folding the
vanesThe flow rate is
increased as the
exhaust gas passes
the narrow passage
→ Increased
turbine & impeller
speed, Increased
compressive forceImproved
low speed torque
4. OPERATING PRINCIPLES
The E-VGT is designed to get more improved engine power in all ranges by controlling the turbine as
follows:
1) How it Works at Low Speed
Normal turbocharger cannot get the turbo effect because the amount of exhaust gas is not enough
and the flow speed is slow in a low speed zone, but VGT allows the flow passage of exhaust to narrow,
resulting in increasing the flow speed of exhaust gas and running the turbine quickly and powerfully.
Therefore, as VGT can intake more air than normal turbocharger, it can give the benefit of the
increased output even in a low speed zone.
Turbocharger lag
The turbocharger is at idle speed when there is no load or it is in the normal driving condition. During
this period, the amount of exhaust gas passing through the turbine is not enough to turn the
compressor wheel (impeller) fast. Therefore, the intake air is not compressed as needed. Because
of this, it takes time for turbocharger to supply the additional power after the accelerator pedal is
depressed. This is called "turbocharger lag".Basic principle at low speed
At low speed, it utilizes the principle of venturi.
For example, when air flows through the venturi
tube, the flow speed is faster and the pressure
is lower at the point "A". In this case, if the inner
diameter of venturi is more narrowed, the flow
speed is so much faster (refer to the equation). ※
Page 267 of 796
06-22
2) How it Works at High Speed
In a high speed zone, the amount of exhaust gas increases and it is accompanied with a great force.
Therefore, if the inner diameter of venturi is more widened, the turbine in the turbocharger by the
releasing force of abundant exhaust gas can deliver a more increased energy to the compressor. The
output will increase in submission to the increase of intake air volume.
Control
rangeTurbocharger driving
mechanismControl
methodEffectImproved
performance
At high
speedExpands the
flow passage for
the exhaust gas
by unfolding the
vanesThe flow rate is
increased due to the
expanded
passage→
Increased turbine &
impeller speed,
Increased
compressive forceImproved
maximum
power
Page 273 of 796

08-4
2. INSPECTION
Possible Cause Action
Coolant level
is
too low- Leak from the radiator
- Leak from the coolant auxiliary tank
- Leak from the heater core- Change the radiator
- Change the coolant auxiliary tank
- Change the heater
- Leak from the coolant hose
connections
- Damaged coolant hose - Reconnect the hose or replace
the clamp
- Change the hose
- Leak from the water pump gasket
- Leak from the water pump internal
seal- Change the gasket
- Change the water pump
- Leak from the water inlet cap
- Leak from the thermostat housing- Change the water inlet cap
gasket
- Change the thermostat sealing
- Incorrect tightening torque of the
cylinder head bolts
- Damaged cylinder head gasket- Tighten the bolts to the specified
torque
- Change the cylinder head gasket
Coolant
temperature is
too high- Coolant leakage (Coolant level is low)
- Improper coolant mixture ratio
- Kinked coolant hose- Add coolant
- Check the coolant concentration
(Anti-freeze)
- Repair or replace the hose
- Defective thermostat
- Defective water pump
- Defective radiator
- Defective coolant auxiliary tank or tank
cap- Change the thermostat
- Change the water pump
- Change the radiator
- Change the coolant auxiliary tank
or tank cap
- Cracks on the cylinder block or
cylinder head
- Clogged coolant passages in the
cylinder block or cylinder head- Change cylinder block or cylinder
head
- Clean the coolant passage
- Clogged radiator core - Clean the radiator core
- Improper operation of cooling fan - Replace the cooling fan or repair
the related circuit
- Defective temperature sensor or
faulty wiring- Replace the sensor or repair the
related wiring
Coolant
temperature is
too low- Thermostat is stuck open - Change the thermostat
- Improper operation of cooling fan - Replace the cooling fan or repair
the related circuit
- Defective temperature sensor or faulty
wiring- Replace the sensor or repair the
related wiring
Page 281 of 796

09-51451-01
2) Troubleshooting for Alternator
Item Cause Action
Overcharged
batteryDefective alternator voltage regulator Replace the alternator
Defective voltage detection wiring Replace the alternator
Defective voltage detection wiring Repair or replace
Discharged battery Loose alternator drive belt Adjust the belt tension or replace
Poor connection of related circuit or
open circuitRetighten the loose connection or
repair open circuit
Defective alternator voltage regulator Replace the alternator
Terminated battery Replace the battery
Defective ground Repair
Charge warning
lamp does not
come on when
turning on ignition
switch with engine
stoppedDefective alternator voltage regulator Replace the alternator
Open circuit in charge warning lamp,
fuse or wiringReplace or repair the charge
warning lamp or fuse
Defective ignition switch Replace the ignition switch
Defective ground of alternator circuit Repair
Charge warning
lamp is not turned
off after starting
engineDefective alternator voltage regulator Replace the alternator
Corroded or worn battery cable Repair or replace the battery cable
Loose alternator drive bel Replace the batteryAdjust the belt
tension or replace the belt
Defective wiring harness Repair or replace
Warning lamp does
not go off even
after starting the
engineCorrosion or damage of
battery cableRepair or replace the
battery cable
Loose alternator drive belt Adjust the belt tension or
replace the belt
Defective wiring harness Repair or replace
Overcharged
batteryDefective voltage regulator of alternator Replace the alternator
Defective voltage detecting wiring Repair or replace
Page 291 of 796
10-4
1. OVERVIEW
The pre-heating system for D20DTR 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 plug
Engine ECU (D20DTR)Glow indicator
Glow plug control unit
(GCU)
Page 311 of 796
13-4
1. SYSTEM DESCRIPTION
1) Overview
The EGR (Electric-Exhaust Gas Recirculation) valve reduces the NOx emission level by recirculating
some of the exhaust gas to the intake system.
To meet Euro-V regulation, the capacity and response rate of E-EGR valve in D20DTR engine have
been greatly improved. The EGR cooler with high capacity reduces the Nox, and the bypass valve
reduces the CO and HC due to EGR gas before warming up.
Also, the engine ECU adjusts the E-EGR opening by using the air mass signal through HFM sensor. If
the exhaust gas gets into the intake manifold when the EGR valve is open, the amount of fresh air
through HFM sensor should be decresed.
Benefits of E-EGR valve ▶
Improved accuracy and response through electric control
Feedback function (Potentiometer)
Preventing chattering of EGR valve and improved durability
Self-cleaning function -
-
-
-
Page 312 of 796
13-51793-00
EGR pipe
Transports the exhaust gas from the EGR cooler
and EGR bypass valve to the intake duct.E-EGR valve
Receives the electric signal from the ECU to
control the valve.
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.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
60˚C or more), atmospheric pressure
(atmospheric pressure sensor: altitude
compensation) are used as auxiliary map values.
2) Location and Components
See the section "Engine control" for E-EGR
valve control logic.EGR coolerEGR bypass
For details, see the section "Engine control".
*
Page 314 of 796

13-71793-00
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 -
-
-
-
-
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
Intake air temperature: between -10 and 50℃
Atmospheric pressure: 0.92 bar or more
Engine coolant temperature: between 0 and 100°C
When there is no fault code related to EGR -
-
-
-
(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 -
-
-
-