S07.10-0011-79
Block diagram |
A1/1 | Instrument cluster (KI) control unit | Y49/10 | Intake camshaft solenoid | |
B11/17 | Coolant temperature sensor | Y49/11 | Exhaust camshaft solenoid | |
B37/4 | Accelerator pedal module | Y62 | Fuel injectors | |
B70/2 | Crankshaft Hall sensor | CAN E | Chassis CAN | |
N3/34 | ME-SFI [ME] control unit | CAN HMI | User interface CAN | |
N80 | Steering column tube module (MRM) control unit | CAN V | Vehicle CAN | |
N93 | Central gateway (CGW) | A | Mercedes-Benz | |
S40/3 | Clutch pedal switch | B | Nissan | |
S40/4 | CRUISE CONTROL lever (with CODE MS1 (Cruise control)) | C | Default | |
T1 | Ignition coils | D | Optional |
Function requirements for deceleration fuel shutoff, general points
Circuit 87 ON (engine management ON)
Engine running.
Accelerator not actuated.
Vehicle not in CC mode (with code MS1 (CC))
Not too high an exhaust temperatures
Deceleration fuel shutoff, general
Deceleration fuel shutoff in deceleration mode of the engine has the following tasks:
increasing the braking effect of the engine.
reducing fuel consumption.
improving exhaust characteristics.
The ME-SFI control unit performs a deceleration fuel shutoff according to the following sensors and signals:
Coolant temperature sensor
Accelerator pedal module
Crankshaft Hall sensor
Clutch pedal switch
CRUISE CONTROL lever (with CODE MS1 (Cruise control))
Deceleration fuel shutoff, function sequence
In deceleration mode, the ME-SFI control unit switches off the fuel injectors dependent on coolant temperature, engaged gear and engine speed, if the accelerator pedal is not actuated.
In addition, the ME-SFI control unit places the camshafts in a position with reduced valve overlap via the intake camshaft actuator solenoid and the exhaust camshaft actuator solenoid. This allows secure combustion without misfires.
The fuel injectors are switched on again when the accelerator pedal is operated.
If the clutch pedal is operated, the trailing throttle fuel cut-off is aborted.
After deceleration fuel shutoff, the ME-SFI [ME] control unit enriches the fuel/air mixture by briefly lengthening the injection period in order to relieve the catalytic converters of enriched oxygen.
In order to prevent a sudden torque rise when combustion is restarted after a deceleration fuel shutoff, the ME-SFI control unit briefly shifts the ignition angles of the ignition coils towards "retard".
The trailing throttle fuel cut-off is suppressed at too high exhaust gas temperatures, because the high oxygen content in the exhaust gas would in this case lead to an increased post combustion of carbon monoxide and hydrocarbons. The heat so generated can overheat of the catalytic converter.