(Injection Regulation, Function - GF07.10-P-1004MMR)

ENGINE 157.9, 278.9 in MODEL 166 

up to model year 2016 

Function requirements for injection regulation, general points 

• Circuit 87M (engine management ON)
• Engine runs

Injection regulation, general points 

The ME-SFI [ME] control unit (N3/10) assigns the required fuel quantity to the engine.

Using the characteristic map, the ME-SFI [ME] control unit calculates the injection period and pressure on the basis of the following sensors and signals:

• Fuel pressure and temperature sensor (B4/25)
• Left and right intake camshaft hall sensors (B6/4, B6/5), intake camshaft positions
• Left and right exhaust camshaft hall sensors (B6/6, B6/7), exhaust camshaft positions
• Coolant temperature sensor (B11/4), coolant temperature
• Remove charge air temperature sensor in charge air distributor (B17/8)
• Pressure sensor downstream of throttle valve (B28/7), engine load
• Accelerator pedal sensor (B37), driver engine load request
• Accelerator pedal sensor, accelerator pedal operation fast or slow (when accelerating)
• Crankshaft Hall sensor (B70), engine rpm
• Left and right oxygen sensors upstream of catalytic converter (G3/3, G3/4)
• Atmospheric pressure sensor in ME-SFI [ME] control unit, atmospheric pressure for altitude adaptation
• Correction programming with the Xentry diagnostics (during acceleration)

The requirements of the torque coordination function are also taken into account.

Function sequence for injection regulation 

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 

The actuation time of the fuel injectors (Y76) is calculated in the ME-SFI [ME] control unit as a function of the lambda control, fuel pressure and the requested engine torque.

At the accelerator pedal sensor, about 10 to 90% slewing range is defined as partial load and more than about 90% slewing range is defined as wide open throttle.

Multiple injection

Partitioning the injection quantity into a number of single fuel injections, whereby the last can be selected to be close to ignition.

Areas of application of multiple injections:

• Start
• Heat up CAT
• Combustion stabilization at high loads and speeds <2000 rpm
• Keep the CAT in idle for long idling phases for a run engine

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.

	Electrical function schematic for injection control		PE07.10-P-2704-97NAF
	Overview of system components for gasoline injection and ignition system with direct injection		GF07.70-P-9998MMG