Injection regulation, function

S07.10-0016-79

Function requirements for injection regulation, general points

 Circuit 87 ON (engine management ON)

 Engine running.

Injection regulation, general points

The engine receives the fuel quantity required in each case from the ME-SFI control unit.

Using the characteristics map, the ME-SFI control unit calculates the injection duration and pressure based on the signals of the following sensors and devices:

 Intake camshaft position sensor, intake camshaft position

 Crankshaft Hall sensor, engine speed

 Hot film mass air flow sensor

 Coolant temperature sensor, coolant temperature

 Oxygen sensor upstream of catalytic converter, residual oxygen

 Oxygen sensor downstream of catalytic converter

 Throttle valve actuator

 Knock sensor

 Atmospheric pressure sensor in ME-SFI [ME] control unit, atmospheric pressure for altitude adaptation

 Accelerator pedal module, engine load request by driver, accelerator pedal operation fast or slow (when accelerating)

 On-board electrical system battery

 Instrument cluster (IC) control unit via central gateway (CGW)

 Signal acquisition and actuation module (SAM) control unit

 Fuse and relay module control unit (SRM)

Function sequence for injection regulation

The fuel quantity injected by the injection valve is controlled via a performance map in the ME-SFI control unit. The programmed value is specified by the engine operating conditions. These conditions are determined by the input signals (for engine speed and intake air) from the crankshaft Hall sensor, the intake camshaft position sensor and the hot film mass air flow sensor.

The ME-SFI [ME] control unit controls the injection period under the following operating conditions:

 Function sequence for partial load and wide open throttle operation

 Function sequence for acceleration

Function sequence for partial load and wide open throttle operation

In the ME-SFI control unit, the actuation time of the fuel injectors is calculated depending on the lambda control, the input signals from the hot film mass air flow sensor, and the requested engine torque.

Function sequence for acceleration

When there is rapid change in the accelerator pedal position, the throttle valve also opens and closes rapidly. This causes the mixture to become briefly leaner or too rich.

To prevent this, the ME-SFI [ME] control unit adapts the fuel/air mixture by lengthening or shortening the actuation time of the fuel injectors according to a characteristics map. This prevents jerking of the engine.