Cylinder Shutoff, Function - GF07.61-P-3033MNE

Engine 177.9 in model 213 

up to model year 2021 

Function requirements, general 

• Engine runs

Cylinder shutoff 

The CSO has the task of reducing the fuel consumption in partial load operation by shutting off cylinders 2, 3, 5, and 8. The shutoff takes place characteristic map dependent by the ME-SFI [ME] control unit (N310).

The following effects of the cylinder shutoff reduce the fuel consumption:

• Increase in the effectiveness by means of operating point shifting of further driven cylinder at higher loads
• Reduction of the charge change losses through closing of the valves of the switched off cylinder

The ME-SFI [ME] control unit reads in signals from the following assembly parts for cylinder shutoff:

• Coolant temperature sensor (B11/4)
• Pressure sensor downstream of left throttle valve (B28/22)
• Pressure sensor downstream of right throttle valve (B28/23)
• Left intake camshaft Hall sensor (B6/4)
• Right intake camshaft Hall sensor (B6/5)
• Left exhaust camshaft Hall sensor (B6/6)
• Right exhaust camshaft Hall sensor (B6/7)
• Crankshaft Hall sensor (B70)
• Actual value potentiometer 1, left (M16/60r1)
• Actual value potentiometer 2, left (M16/60r2)
• Actual value potentiometer 1, right (M16/61 r1)
• Actual value potentiometer 2, right (M16/61r2)
• The IC (A1) transmits the vehicle speed via the user interface CAN (CAN C), the electronic ignition lock control unit (N73), the chassis FlexRay (Flex E), powertrain control unit (N127) and drive train CAN (C1) to the ME-SFI [ME] control unit.
• The Electronic Stability Program control unit (N30/4) transmits the wheel speeds via the chassis FlexRay, the powertrain control unit and the drive train CAN to the ME-SFI [ME] control unit.
• The fully integrated transmission control unit (Y3/8n4) sends information on the gear range engaged via the drive train CAN to the ME-SFI [ME] control unit.

The ME-SFI [ME] control unit takes the following measures for CSO:

• Cutting out of the fuel injectors
  • Cylinder 1 fuel injector (Y76/1)
  • Cylinder 2 fuel injector (Y76/2)
  • Cylinder 3 fuel injector (Y76/3)
  • Cylinder 4 fuel injector (Y76/4)
  • Cylinder 5 fuel injector (Y76/5)
  • Cylinder 6 fuel injector (Y76/6)
  • Cylinder 7 fuel injector (Y76/7)
  • Cylinder 8 fuel injector (Y76/8)
• Cutting out of the ignition coils
  • Cylinder 1 + 2 ignition coil (T4)
    • Cylinder 1 ignition coil (T4t1)
    • Cylinder 2 ignition coil (T4t2)
  • Ignition coil, cylinders 3 + 4 (T4/1)
    • Cylinder 3 ignition coil (T4/1t3)
    • Cylinder 4 ignition coil (T4/1t4)
  • Ignition coil, cylinders 5 + 6 (T4/2)
    • Cylinder 5 ignition coil (T4/2t5)
    • Cylinder 6 ignition coil (T4/2t6)
  • Ignition coil, cylinders 7 + 8 (T4/3)
    • Cylinder 7 ignition coil (T4/3t7)
    • Cylinder 8 ignition coil (T4/3t8)
• Plugging the intake valves
  • Cylinder 2 intake CAMTRONIC actuator (Y49/11)
  • Cylinder 3 intake CAMTRONIC actuator (Y49/13)
  • Cylinder 5 intake CAMTRONIC actuator (Y49/15)
  • Cylinder 8 intake CAMTRONIC actuator (Y49/17)
• Plugging the exhaust valves
  • Cylinder 2 exhaust CAMTRONIC actuator (Y49/12)
  • Cylinder 3 exhaust CAMTRONIC actuator (Y49/14)
  • Cylinder 5 exhaust CAMTRONIC actuator (Y49/16)
  • Cylinder 8 exhaust CAMTRONIC actuator (Y49/18)

Diagram of CSO and firing order 

Courtesy of MERCEDES-BENZ USA

CSO is performed under the following conditions: 

• Transmission mode "C" and "ECO" activated
• Coolant temperature between 30 and 110°C
• Vehicle speed between 20 and 140 km/h
• Engine rpm between 1000 and 3250 rpm
• Control unit temperature a maximum of 105°C
• System diagnosis complete and system fault-free
• no mixture adaptation

The CSO is deactivated under the following conditions: 

• Ignition misfires "damaging to the catalytic converter" recognized
• Cylinder shutoff fault detected
• Electronic accelerator limp-home mode
• Irregular engine running when the activated cylinder shutoff is too large
• Maximum permissible, uninterrupted operating time of approx. 600 s exceeded

The ME-SFI [ME] control unit actuates the CAMTRONIC actuators with a pulse width modulated signal. In doing so, a coil is energized in the CAMTRONIC actuator and a plunger moves into a curved track on the cam sleeve. Due to the turning of the camshaft and the design of the curved track, the cam sleeve is shifted axially on the camshaft. The roller-type cam follower is decoupled from the camshaft by the axial shifting and the valve remains closed due to the spring force of the valve spring. A bump in the curved track has the effect of bringing the tappet back to the default position. To reset the cam sleeve a second plunger in moves in the respective curved track. The resetting occurs analogously. The position of the plunger is detected by an integral Hall sensor.

Sectional view of the cylinder head cover of the left cylinder bank 

Courtesy of MERCEDES-BENZ USA

During CSO condensing exhaust gases can deposit on the spark plugs and on the combustion chamber walls (sooting). This can be prevented if the valves are opened at certain intervals and the included air renewed dependent on the engine load and the engine rpm.

In order to improve the neutrality of torques and to reduce the load on components, fresh air is included during the CSO in each switched off cylinder in the form of a pneumatic spring. To do this the intake valves are opened for a short time if the piston has reached BDC.

	Electrical function schematic for CSO		PE07.61-P-2794-97DBG
	Overview of system components for gasoline injection and ignition system with direct injection		GF07.70-P-9998MNE