Fuel Control - SSANGYONG Rodius 2012.07 Manual

- A fourth correction is made according to the pressure error.
This correction is used to reduce the injection timing advance when the pressure in the rail is higher
than the pressure demand.
- A fifth correction is made according to the rate of EGR.
This correction is used to correct the injection timing advance as a function of the rate of exhaust gas
recirculation.
When the EGR rate increases, the injection timing advance must in fact be increased in order to
compensate for the fall in termperature in the cylinder.

(5) Fuel Control

A. 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.
- 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.
B. Driver Demand
The driver demand is the translation of the pedal position into the fuel demand. It is calculated as a
function of the pedal position and of the engine speed. The driver demand is filtered in order to limit the
hesitations caused by rapid changes of the pedal position. A mapping determines the maximum fuel
which can be injected as a function of the driver demand and the rail pressure. Since the flow is
proportional to the injection time and to the square root of the injection pressure, it is necessary to limit
the flow according to the pressure in order to avoid extending the injection for too long into the engine
cycle. The system compares the driver demand with this limit and chooses the smaller of the 2 values.
The driver demand is then corrected according to the coolant temperature. This correction is added to
the driver demand.
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