ME-SFI start quantity control, function

P07.61-2691-01

t1 Start quantity control (duration e.g. 2 s)

t2 Post-start enrichment (duration e.g. 15 seconds at coolant temperature of 15°C)

t3 Warm-up control (duration in line with coolant temperature)

a Start

b Start of cutoff of post-start enrichment

c Start of warm-up control

t Time

A Enrichment rate

Function

In order to facilitate starting of a cold engine, fuel must also be injected during the starting procedure depending on the coolant temperature. The increased injection quantity (start quantity) is achieved by extending the injection time.

The start quantity control is enabled after start recognition. It remains activated until a temperature-related idle speed is exceeded.

The higher the coolant temperature, the lower the start quantity metered by the ME-SFI control unit (N3/10).

The start quantity control is dependent on:

 Start recognition

 Coolant temperature

 Engine speed

 Altitude (atmospheric pressure)