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Voltage pattern in actual stepGCU PWM control
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.
Duty control area:
Between 5 and 100%
Frequency: 20 Hz
1.
2.
3.
(1) Temperature/Current Properties of GCU
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. 1.
2.
3.
Frequency:
20~33Hz
PWM control duty
ratio
- 1st step: 100%
- 2nd step: 35%
- 3rd step: 23%
This describes the voltage supplying types to glow plugs. This shows the supplying voltage and
time by GCU in each step. The 3rd
step is the period to keep the
temperature.
(2) Operation Type of GCU
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1793-00
1. SPECIFICATION
Item Specification
E-EGR valveMotorEGR response time 50 ms
Driven by DC motor
Valve EGR gas flow rate 120 kg/h
Cooling capacity 8.3 kW or more
Cooling fin type Wavy fin
Cooler type U-shaped
E-EGR bypass valve Solenoid valve Drivien byVacuum
(Solenoid valve)
E-EGR cooler
Position sensorSensing type Hole sensor
Supplied voltageMaximum signal
range5% ~ 95%
Maximum power
consumption
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0000-00
c. Main Injection
The power of the vehicle is determined by the main fuel injection volume.
Main injection calculates the fuel volume based on pilot injection. The calculation uses the value for
accelerator pedal position, engine rpm, coolant temperature, intake air temperature, boost pressure,
boost temperature and atmospheric pressure etc.
d. Post Injection
Injection after main injection. Consists of After injection, Post 1, Post 2 injection.
Post injection reduces PM and smoke from exhaust gas. No actual output is generated during these
injections, instead, fuel is injected to the unburned gas after main injection to enable fuel activation. The
PM amount in the emission and smoke can be reduced through these processes.
Only up to 5 types of injections can be performed within 1 cycle. If these 7 injections are all performed,
fuel economy and emission performance becomes poor.
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1725-12
Throttle bodies by engine type
The throttle valve is controlled by electric signals sent from the engine ECU for optimal
fuel injection volume, engine load and effective combustion of EGR gas according to
the Euro 4 regulations. It has following functions by the engine type. -