SsangYong Korando III (2010 year). Service manual — part 59
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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 Hz
Duty ratio = (RMS voltage)²
(Battery voltage)²
1.
2.
3.
(1) Characteristics of temperature and current in AQGS
AQGS unit increases the glow plug temperature very rapidly (1,000˚C in 2 seconds).
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 Control
Actual 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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(3) Operating Steps
Pre-Glow: Step 1
▶
If normal communication with the ECU is established 2 seconds after the power is supplied to the IGN
terminal from the battery, the GCU supplies the battery power to raise the temperature of the glow plug
to 1000℃ by the preheating request from the engine ECU before starting.
- The time for pre-heating is controlled by the ECU.
If the input voltage (VB) is 11.5 V or less, GCU supplies the battery voltage for preheating time (T1).
If the input voltage (VB) is greater than 11.5 V, GCU supplies the voltage of 11.5 V for preheating time
(T1).
-
-
The preheating time may vary according to the conditions.
Input voltage
VB (V)
Pre-heating time T1
(sec)
6 8.27
7 5.8
8 4.1
9 3.15
10 2.4
11 1.95
≥ 11.5
1.9
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During cranking: Step 2 and step 3
▶
Step 2: If the ECU receives the cranking signal after pre-heating (step 1), the GCU supplies the
voltage of 6.8 V for 1 sec to raise the temperature to 1,100℃.
Step 3: The GCU supplies the voltage of 5.1 V to keep the temperature at 1,000°C.
1.
2.
Under fixed temperature: The AQGS unit supplies power for 30 seconds (Step 1 + Step 3) if no
cranking signal is received after the step 1.
During cranking: The step 3 is started after the step 2.
*
*
Post-glow: Step 4:
▶
The post-heating is for reducing HC/CO after the engine is started. If the time for post-heating exceeds
180 sec., the GCU unit cuts off the power to each glow plug even if there is preheating request from the
engine ECU.
Emergency glow
▶
If no CAN signal is received for 4 seconds from the engine ECU after the IGN ON signal is input, the
GCU performs emergency preheating (Step 3) for 30 seconds.
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Normal operating mode
▶
This shows the components of preheating system in the pre-heating and the post-heating steps.
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