Injection Regulation, Function - GF07.10-S-1004TRC

Engine 274 in model 447, 448 

except code XM0 (Facelift) 

Function requirements for injection regulation, general points 

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

Injection regulation, general points 

The ME-SFI [ME] control unit (N3/34) assigns the required fuel quantity to the engine.

Using the characteristics map, the ME-SFI [ME] control unit (N3/34) calculates the injection period and pressure on the basis of the following sensors and signals:

• Fuel pressure and temperature sensor (B4/21)
• Intake camshaft Hall sensor (B6/29)
• Exhaust camshaft Hall sensor (B6/30)
• Coolant temperature sensor (B11/21)
• Charge air temperature sensor upstream of throttle valve (B17)
• Charge air temperature sensor downstream of throttle valve (B17/16)
• Intake manifold pressure sensor (B28/24)
• Accelerator pedal module (B37/4), engine load request from driver
• Accelerator pedal module (B37/4), accelerator pedal operation fast or slow (when accelerating)
• Crankshaft Hall sensor (B70/2)
• Oxygen sensor downstream of catalytic converter (G3/21)
• Oxygen sensor upstream of catalytic converter (G8/6)
• Atmospheric pressure sensor in ME-SFI [ME] control unit (N3/34)
• Correction programming using 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 (N3/34) controls the injection period under the following operating conditions:

• Function sequence for neutral, partial load and wide open throttle operation 
• Function sequence for acceleration 

Function sequence for neutral, partial load and wide open throttle operation 

The actuation time of the fuel injectors (N3) is calculated in the ME-SFI [ME] control unit (Y62/34) depending on the lambda control, the fuel pressure in the rail and the requested engine torque.

At the accelerator pedal sensor in the accelerator pedal module (B374) about 10% to 90% of the slewing range is defined as partial load and for more than about 90% of the 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.

Use phases:

• Start
• Heat up catalytic converters
• Combustion stabilization at high loads and speeds <2000 rpm
• Keep CATs warms during long idling phases

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 (N3/34) adapts the fuel/air mixture by lengthening or shortening the actuation time of the fuel injectors (Y62) according to a characteristics map. This prevents jerking of the engine.

	Electrical function schematic for injection control	Engine 274 in model 448 except code XM0 (Facelift)	PE07.10-S-2704-97VDC
		Engine 274 in model 447 except code XM0 (Facelift)	PE07.10-S-2704-97TRC
	Overview of system components for gasoline injection and ignition system with direct injection		GF07.70-S-9998TRC