5 Series E60 M5 (S85) SAL
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Injection quantity
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Injection start
Adjustment of the variable camshaft control and positioning of the 10 individual throttle butterflies is
synchronised with this.
[more ...]
System functions
The following system functions are described:
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Knock control and misfire detection with ionic current measurement
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Torque feedback control operation
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Double VANOS variable camshaft control
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Vacuum supply
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Oil supply
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Fuel supply system
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Exhaust system
Knock control and misfire detection with ionic current measurement
Due to the extremely high engine speeds, the S85B50 places very special demands on components and system
functions. One example of this is the knock control.
Conventional knock sensors would be unsuitable as they cannot deliver adequate signals at these high engine
speeds.
Ionic current measurement is used instead and is carried out by 2 ionic current control units. One of these
control units is positioned at the front of each cylinder bank on the cylinder head cover. The ionic current control
unit is connected to the DME control module and the ignition coils. The DME control module and the ignition
coils are not directly connected.
The ionic current measurement is carried out as follows:
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The DME control module triggers the ignition sparks at the spark plug. This ignites the fuel-air mixture
which starts to burn.
•
The resulting heat energy creates positively and negatively charged molecules (= ions). The number of ions
produced increases according to the combustion temperature. The more efficient the combustion, the more
ions are produced.
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A DC voltage is applied at the spark plug by the ionic current control unit immediately following ignition. If
free ions are present in the mixture, current flows. The ionic current control unit measures and evaluates
this "ionic current".
The ionic current control unit measures and amplifies this ionic current. The DME evaluates this ionic
current.
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The DME control module detects ionic current which is too low during ignition and combustion (no ignition
sparks or poor combustion), as well as combustion knock.
•
If discrepancies are detected, the DME control module makes adjustments.
The ionic current measurement detects:
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Combustion knock
•
Misfiring
The ionic current measurement is also capable of analysing each individual combustion process through all
engine speed ranges.
SBT S85B50 engine E60, E61 M5 E63, E64 M6
BMW AG - TIS
23.02.2013 19:32
Issue status (12/2007) Valid only until next DVD is issued
Copyright
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