Injection Regulation, Function - GF07.10-P-1004MRH

Engine 274.9 in model 205.047/053/054/147/247/253 

Engine 274.9 in model 253.353/953 

Engine 274.9 in model 253.354/954 

Function requirements for injection regulation, general points 

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

Injection regulation, general points 

The ME-SFI 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)
• intake camshaft Hall sensor (B6/15), intake camshaft setting
• Exhaust camshaft Hall sensor (B6/16), exhaust camshaft setting
• Coolant temperature sensor (B11/4)
• Charge air temperature sensor upstream of throttle valve (B17/7)
• Charge air temperature sensor downstream of throttle valve (B17/9)
• Pressure sensor downstream of throttle valve (B28/7), Engine load
• Accelerator pedal sensor (B37), driver Engine load request As of facelift: The powertrain control unit (N127) reads in the signals of the accelerator pedal sensor and transmits these via the drive train CAN (CAN C1) to the ME-SFI [ME] control unit.
• Up to facelift: accelerator pedal module control unit (B37n1), via drive train CAN, powertrain control unit, and Engine CAN (CAN C)
• Oxygen sensor sensor elements downstream and upstream of the catalytic converter (G3/1 b1, G3/2b1)
• Atmospheric pressure sensor in ME-SFI control unit, atmospheric pressure for altitude adaptation
• Correction programming with XENTRY Diagnosis

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

The accelerator pedal module sensor (B37b1) records the position of the accelerator pedal module actuator motor (B37m1).

Function sequence for injection regulation 

The ME-SFI 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 (Y76/1 to Y76/4) is calculated in the ME-SFI [ME] control unit depending on the lambda control, the fuel pressure in the rail 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-2704-97FBH
	Overview of system components for gasoline injection and ignition system with direct injection		GF07.70-P-9998MRH