BMW S58 Owner's Handbook Manual page 63

S58￿Engine
7.￿Oil￿Supply
The￿following￿operating￿condition￿opens￿the￿piston￿cooling￿relay￿valve￿and￿activates￿piston￿cooling:
• Oil￿pressure￿from￿the￿main￿oil￿duct￿>￿1￿bar.
- Piston￿is￿moved￿against￿the￿spring￿force.
- Channel￿to￿the￿oil￿spray￿nozzles￿is￿opened￿and￿the￿pistons￿are￿cooled.
- Oil￿that￿is￿behind￿the￿piston￿can￿drain￿into￿the￿crank￿chamber￿via￿the￿control￿channel,￿the
piston￿cooling￿control￿valve￿and￿the￿return￿channel.
The￿following￿operating￿conditions￿prevent￿the￿piston￿cooling￿relay￿valve￿from￿opening￿and￿deactivate
piston￿cooling:
• Oil￿pressure￿from￿the￿main￿oil￿duct￿<￿1￿bar.
- Spring￿force￿is￿greater￿than￿the￿oil￿pressure￿from￿the￿main￿oil￿duct.
- Channel￿to￿the￿oil￿spray￿nozzles￿is￿not￿opened.
• Piston￿cooling￿control￿valve￿energized.
- Oil￿is￿directed￿from￿the￿piston￿cooling￿control￿valve￿through￿the￿control￿channel￿to￿the
space￿behind￿the￿pistons￿of￿the￿piston￿cooling￿relay￿valve.
- Oil￿pressure￿and￿spring￿force￿generate￿a￿back-pressure￿and￿seal￿off￿the￿piston￿cooling￿relay
valve￿from￿the￿main￿oil￿duct.
- The￿channel￿to￿the￿oil￿spray￿nozzles￿can￿no￿longer￿be￿opened.
Illustration￿of￿central￿valve￿functions
S58￿engine,￿illustration￿of￿central￿valve￿function
Index
A
B
C
D
E
Explanation
Piston￿cooling￿control￿valve￿de-energized,￿oil￿pressure￿in￿main￿oil￿duct￿>￿1 bar.
Piston￿cooling￿active
Piston￿cooling￿control￿valve￿de-energized,￿oil￿pressure￿in￿main￿oil￿duct￿<￿1 bar.
Piston￿cooling￿deactivated
Piston￿cooling￿control￿valve￿energized,￿oil￿pressure￿in￿main￿oil￿duct￿>￿1 bar.
Piston￿cooling￿deactivated
Oil￿pressure
Depressurized
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