Injection regulation, function - GF07.10-P-1004MMA

ENGINE 157.9 in MODEL 212, 218 

ENGINE 278.9 in MODEL 207, 212, 218 

ENGINE 157.9 in MODEL 212, 218 

ENGINE 278.9 in MODEL 207, 212, 218 

Function requirements for injection regulation, general points 

• Circuit 87M ON (engine timing ON)
• Engine running

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 time 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) (model 207, 212), coolant temperature sensor (B11/4) (model 218)
• Charge air temperature sensor (B17/8)
• Pressure sensor downstream of throttle valve (B28/7), engine load
• Accelerator pedal sensor (B37), engine load request from the driver
• Accelerator pedal sensor, accelerator pedal operation fast or slow (with acceleration)
• Crankshaft Hall sensor (B70), engine speed
• Left and right oxygen sensors upstream of catalytic converter (G3/3, G3/4)
• Altitude pressure sensor in ME-SFI [ME] control unit, atmospheric pressure for altitude adaptation
• Correction programming with Xentry Diagnostics

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 time 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 depending on the lambda control, the rail 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 catalytic converters
• Combustion stabilization at high loads and speeds <2000 RPM
• Keep catalytic converters warm in idle with long idle phases with engine running

Function sequence for acceleration 

When there is rapid variation of the accelerator pedal position, the throttle valve also opens and closes rapidly. This causes the mixture to become briefly leaner or richer.

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

	Electrical function schematic for injection control	MODEL 207	PE07.10-P-2704-97EAI
		MODEL 212	PE07.10-P-2704-97DAK
		Model 218	PE07.10-P-2704-97XAC
	Overview of system components for gasoline injection and ignition system with direct injection	ENGINE 157.9 in MODEL 212, 218 ENGINE 278.9 in MODEL 207, 212, 218	GF07.70-P-9998MM