3 Series E46 318ti (N42) COMP
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Spark-over in high-tension circuit parallel to spark gab where a short-circuit in the coil does not develop
Alternator actuation (bit-serial data interface)
The following functions have been implemented in the DME control unit for the alternator with bit-serial data
interface:
•
Switching the alternator on and off using defined parameters
•
Specification of the alternator's maximum permissible power consumption
•
Calculation of the input torque for the alternator based on the power consumption
•
control of the alternator's response when higher electrical loads are connected (Load-Response function)
•
Diagnosis for the data line between the alternator and DME control unit
•
Storage of faults which develop in the alternator in the fault memory of the DME control unit
•
Actuation of the charge-current indicator light in the instrument cluster via bus connection
The principal function of the alternator is also guaranteed when communication between the alternator and DME
control unit is interrupted.
The following fault causes can be distinguished in fault memory entries:
•
Overheating protection:
The alternator is overloaded. For safety reasons, the alternator voltage is reduced until the alternator has
cooled down (charge telltale light does not light up).
•
Mechanical fault:
There is a mechanical block in the alternator. or: The belt drive is defective.
•
Electrical fault:
Excitation diode defective, excitation coil has been interrupted, overvoltage due to defective governor.
•
Communication failure:
Line between DME control unit and alternator defective.
An interruption or short circuit in the alternator coils will not be detected.
Engine cooling
The opening and closing of the map thermostat (N46 only) is controlled by a characteristic map. This regulating
operation can be split into 3 operating ranges:
•
Mapped thermostat closed:
The coolant only flows through the engine and the coolant circuit is closed.
•
Mapped thermostat open:
The entire coolant volume flows through the radiator. This results in maximum use of the available cooling
output.
•
Control range of the mapped thermostat:
A proportion of the coolant flows through the radiator. The mapped thermostat maintains a constant coolant
temperature within the control range at the engine inlet.
In this operating range, the coolant temperature can now be selectively controlled with the assistance of the
mapped thermostat. This means that a high coolant temperature can be set in the part-load range of the
engine. High operating temperatures in the part-load range result in improved combustion. This in turn
leads to reduced consumption and exhaust emissions.
During full load operation, certain disadvantages are associated with higher operating temperatures
(retarding of ignition due to knock).
A lower coolant temperature is therefore specifically set during full load operation with the assistance of the
SBT Engine control for N45, N46 E46, E60, E81, E83, E85, E87, E90, E91, E92, E93
BMW AG - TIS
12.02.2013 21:13
Issue status (12/2007) Valid only until next DVD is issued
Copyright
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