Page 233 - Foton Workshop Manual - Aumark (BJ1099)

ENGINE CONTROL SYSTEM - ENGINE CONTROL SYSTEM 11-7
INTRODUCTION TO SYSTEM FUNCTION

1. Start control
• In the process of starting, it adopts the special method of calculation to control the
charge, injection and ignition timing.
• At the beginning of the process, the air in the intake manifold is still, the internal
pressure of intake manifold is shown as the surrounding atmospheric pressure.
Open the electronic throttle to a certain angle, of which size is a fixed parameter
according to the starting temperature.
• The amount of fuel injection changes according to the temperature of the engine, 11
in order to promote the oil film to be formed on the intake manifold and cylinder
wall. Before the engine reaches a certain speed, the enrichment of mixture shall
be made. Once the engine starts to run, the system shall immediately start to
reduce the start enrichment, until the state of starting operation ends (the engine
speed reaches 600 - 700r/min), it shall completely cancel the start enrichment.
• Under the state of starting operation, the ignition angle shall also be adjusted,
changing with the engine temperature, intake temperature and engine speed.

2. Warming up and heat control of ternary catalytic converter
• After the cold-starting of the engine, all of air charge, fuel injection and ignition
in the air cylinder are adjusted to compensate the higher torque requirement
of the engine. This process is continued until the engine temperature rises to a
certain threshold (the engine temperature is approximate to the engine coolant
temperature).
• The function of ternary catalytic converter is to convert the harmful gas exhausted
from the combustion in the engine into harmless gas and then discharge it into
the atmosphere.
• Due to that the working temperature of ternary catalytic converter is more than
300℃ , the most important thing in the process of warming up is the rapid heating
of ternary catalytic converter. Under such condition, it may adopt the method of
appropriately delaying the advance angle of ignition to conduct the heating of
ternary catalytic converter by using exhaust gas.

3. Idle speed control
• The function of idle speed control refers to the control of the system for the engine
speed when the accelerator pedal is not pressed.
• Idle speed control includes the control of stabilizing the engine speed when the
vehicle runs at the idle speed. It also includes the idle regulator control when the
load is increased, for example, in case of opening the air conditioning, power
steering, opening headlight, etc.
• The system uses a step motor (integrated in the electronic throttle body) to
automatically adjust the throttle opening angle, so as to achieve a high precision
idle speed control.

Page 233