SSANGYONG KYRON 2010.01 Manual page 122

6. FUEL FLOW CONTROL
1) Main Flow Control
The main flow represents the amount of fuel injected into the cylinder during the main injection.
The pilot flow represents the amount of fuel injected during the pilot injection.
The total fuel injected during 1 cycle (main flow + pilot flow) is determined in the following
manner.
: The driver's demand is compared with the value of the minimum flow determined by the idle
speed controller.
- When the driver depress the pedal, it is his demand which is taken into account by the
system in order to determine the fuel injected.
-
When the driver release the pedal, the idle speed controller takes over to determine the
minimum fuel which must be injected into the cylinder to prevent the enigne from stalling.
It is therefore the greater of these 2 values which is retained by the system. This value is then
compared with the lower flow limit determined by the ASR trajectory control system. As soon as
the injected fuel becomes lower than the flow limit determined by the ASR trajectory control
system, the antagonistic torque (engine brake) transmitted to the drive wheels exceeds the
adherence capacity of the vehicle and there is therefore a risk of the drive wheels locking. The
system thus chooses the greater of these 2 values (main flow & pilot flow) in order to prevent
any loss of control of the vehicle during a sharp deceleration.
This value is then compared with the flow limit determined by the cruise control. As soon as the
injected fuel becomes lower than the flow limit determined by the cruise control, the vehicle's
speed falls below the value required by the driver. The system therefore chooses the greater of
these 2 values in order to maintain the speed at the required level.
This valve is then compared with the flow limit determined by the flow limitation strategy. This
strategy allows the flow to be limited as a function of the operating conditions of the engine. The
system therefore chooses the smaller of these 2 values in order to protect the engine. This
value is then compared with the fuel limit determined by the ASR trajectory control system.
As soon as the injected fuel becomes higher than the fuel limit determined by the ASR
trajectory control system, the engine torque transmitted to the wheels exceeds the adhesion
capacity of the vehicle and there is a risk of the drive wheels skidding. The system therefore
chooses the smaller of the two values in order to avoid any loss of control of the vehicle during
accelerations.
The anti-oscillation strategy makes it possible to compensate for fluctuations in engine speed
during transient conditions. This strategy leads to a fuel correction which is added to the total
fuel of each cylinder. The correction is determined before each injection as a function of the
instantaneous engine speed.
09-11
1491-01
ENGINE CONTROL SYSTEM
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