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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)
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4) 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 data (engine rpm, coolant temperature, vehicle speed) through CAN lines.
Based on the data, GCU controls the pre-glow, cranking and post-glow. It also checks the glow
plugs, and sends the result to ECU.
(1) Temperature/Current Properties of GCU
GCU increases the temperature of glow plug very rapidly (approx. 2 seconds up to
1000°C)
FETs (similar to transistor) for each cylinder are integrated in GCU. During the pre-
glow period, battery voltage is supplied to the glow plugs directly to heat them rapidly.
After getting the desired temperature by pre-glowing, the temperature is controlled by
duty ratio. Step 1:
Step 2 & 3:
Step 4:
This shows the supplying voltage and time by GCU in each step. The step 4 is the period to
keep the temperature. -Step 1: I1
Step 2: I2
Step 3: I3
Step 4: I4
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2. TROUBLESHOOTING
Problem Possible Cause Action
Engine will not crankLow battery voltage Charge or replace
Loose, corroded or damaged battery cable
Repair or replace
Faulty starter or open circuit
Faulty ignition switch or blown fuseRepair or replace
Poor engine ground Repair
Engine cranks too
slowLow battery voltage Charge or replac
Loose, corroded or damaged battery cable
Repair or replace Faulty starter
Starter does not
stopFaulty starter
Faulty ignition switch Replace
Engine cranks
normally, but does
not startBroken pinion gear or faulty starter
Replace the starter
Broken flywheel ring gear Replace
Open circuit Repair
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1. SYSTEM DESCRIPTION
The starter (start motor) starts the engine with rotational power by converting the electric energy to
the mechanical energy.
When the engine is cranking, the pinion gear meshes with the ring gear. If the ring gear overruns,
the pinion gear clutch overruns to protect the pinion gear.
2. OPERATING PROCESS
1) System Layout
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2. CONFIGURATION
1) Circuit Diagram
The engine ECU detects the operating conditions of cruise control system, and monitors the
braking performance, vehicle speed, road conditions and ESP system operation. If the engine
ECU determines that there are not any problem to drive in cruise control mode, the vehicle can be
operated by cruise switch signals (decelerating, accelerating, cruising).
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Do not move the shift lever to Neutral position while driving with the cruise control turned on.
Otherwise, it may result in system malfunction or accidents.
Always be prepared to use the brake or accelerator pedal for safe driving while the cruise
control system is running.
The actual speed can be different from the set speed momentarily when driving on a uphill
or downhill. So, it is recommended to disable the cruise control function on a uphill or
downhill. hen driving on a steep hill use the engine brake and foot brake properly to protect
the vehicle system and for a safe driving.
Ensure that the safe distance is maintained and use the brake pedal if needed. 1.
2.
3.
4.
(1) Abnormal Cancellation of the Cruise Control
When the rapid deceleration is applied without braking.
When the rapid acceleration is applied without acceleration pedal intervention.
When the cruise control lever is faulty.
When the brake switch and the brake light switch input signal are implausible. 1.
2.
3.
When the cruise control function is cancelled abnormally or intermittent problems occur, stop the
vehicle and turn off the ignition switch and remove the key to reset the system. After a while, turn
on the ignition switch again to operate the cruise control system.
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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 -
-
-
-
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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". *