SSANGYONG RODIUS 2005.07, Manual

Page: 156 / 502

09-10
RODIUS 2005.07
0452-01
ENGINE CONTROL SYSTEM
1) Starting Mode
When the ignition is turned ON, the ECM turns the fuel pump relay on for 1 second.
The fuel pump then builds fuel pressure.
The ECM also checks the Engine Coolant Temperature (ECT) sensor and the Throttle Position
(TP) sensor and determines the proper air/fuel ratio for starting the engine.
This ranges from1.5 to 1 at
-36°C (-33°F)
coolant temperature to 14.7 to 1 at
94°C
(201°F) coolant temperature.
The ECM controls the amount of fuel delivered in the starting mode by changing how long the
fuel injector is turned on and off.
This is done by
‘‘pulsing”
the fuel injectors for very short times.
The run mode has two conditions called ‘‘open loop” and ‘‘closed loop”.
2) Run Mode
3) Open Loop
When the engine is first started and it is above 690 rpm, the system goes into
“open
loop”
operation. In
“open loop”,
the ECM ignores the signal from the O2S and calculates
the air/fuel ratio based on inputs from the ECT sensor and the MAF sensor.
The ECM stays in
“open loop”
until the following conditions are met:
The O2 has a varying voltage output, showing that it is hot enough to operate properly.
The ECT sensor is above a specified temperature (22. 5°C).
A specific amount of time has elapsed after starting the engine.
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-
-
4) Closed Loop
The specific values for the above conditions vary with different engines and are stored in the
Electronically Erasable programmable Read-Only Memory (EEPROM).
When these conditions are met, the system goes into
“closed loop” operation. In “closed
loop”,
the ECM calculates the air/fuel ratio (fuel injector on-time) based on the signals
from the O2 sensors.
This allows the air/fuel ratio to stay very close to 14.7 to 1.
5) Acceleration Mode
The ECM responds to rapid changes in throttle position and airflow and provides extra fuel.
The ECM responds to changes in throttle position and airflow and reduces the amount of fuel.
When deceleration is very fast, the ECM can cut off fuel completely for short periods of time.
6) Deceleration Mode