BMW S58, Owner'S Handbook Manual

Page: 65 / 102

S58�Engine
7.�Oil�Supply
59
Index Explanation
1 Engine�oil�cooler
2 Engine�oil�pipe,�return
3 Thermostat
4 Oil�filter
5 Engine�oil�pipe,�supply
The�thermostat�opens�and�closes�under�the�following�three�operating�conditions:
• Engine�oil�temperature�<�100�±2 °C�(212�±35�°F):�The�entire�oil�flow�is�passes�directly�through
the�oil�filter.
• Engine�oil�temperature�100�±2 °C�-�114�±2 °C�(212�±35�°F�-�237�±35�°F�):�Part�of�the�oil�flow
passes�through�the�engine�oil�cooler�and�then�through�the�oil�filter,�the�rest�passes�directly
through�the�oil�filter.
• Engine�oil�temperature�>�114�±�2 °C�(237�±35�°F�):�The�flow�through�the�engine�oil�cooler�is
regulated�in�order�to�obtain�the�target�engine�oil�temperature.
100 °C�(212�°F)�is�chosen�as�the�initial�opening�temperature�because�then�the�condensation�water�in
the�oil�evaporates�through�the�crankcase�ventilation�system.
7.9.�Engine�oil�monitoring
7.9.1.�Oil�pressure
Because�the�S58�engine�has�a�data-map�controlled�oil�pump,�it�is�necessary�to�precisely�register�the
oil�pressure.�For�that�reason,�an�oil�pressure�sensor�is�used.
The�advantages�of�the�sensor�are:
• Measurement�of�the�absolute�pressure�(previously�used�relative�pressure)
• Characteristic�map�control�possible�at�every�engine�speed
7.9.2.�Oil�temperature
The�familiar�oil�temperature�sensor�from�the�N55�engine�is�used�to�measure�the�oil�temperature.
7.9.3.�Oil�level
The�familiar�oil-level�sensor,�which�simultaneously�measures�the�temperature�in�the�sump,�is�used�to
measure�the�oil�level.