ME-SFI Warming-Up Control Function

ME-SFI Warming-up Control Function




Shown on Engine 119
B2/5 Hot film mass air flow sensor
B11/4 Coolant temperature sensor
B17 Intake air temperature sensor
B37 Accelerator pedal sensor
L5 Crankshaft position sensor
M16/1 Electronic accelerator (EA)/ cruise control (CC)/ idle speed control (ISC) actuator
N3/10 ME-SFI control unit
X11/4 Data link connector
Y62 Injectors (LH-SFI, HFM-SFI, PEC [LH, HFM, PMS])




t1 Starting mixture enrichment (duration e.g. approx. 2 seconds)
t2 Post-start enrichment (duration e.g. approx. 2 seconds)
t3 Warming-up phase (duration dependent on coolant temperature)
A Enrichment rate
a Start
b End of start, start of cutoff of post-start enrichment
c End of post-start enrichment, start of warming-up control

Task
Further enriching the fuel-air mixture after start and post-start enrichment because part of the fuel-air mixture precipitates on cold parts of the engine.

Design/function
The additional quantity of fuel is metered to the engine in line with the map. The injection time is extended accordingly for this purpose.

The warming-up enrichment is dependent on:
- Coolant temperature
- Intake air temperature
- Charge air temperature in supercharged engines
- Engine speed
- Engine load
- Idle speed/part load operation
- Correction programming with HHT or STAR DIAGNOSIS