Electrical￿Wastegate￿Valve￿Actuator - BMW S58 Owner's Handbook Manual

S58￿Engine
8.￿Intake￿Air￿and￿Exhaust￿System
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The￿S58￿engine￿has￿a￿twin-turbocharger￿system￿using￿mono-scroll￿turbochargers￿as￿also￿used￿on￿the
S55￿engine.￿The￿system￿supplier￿for￿the￿mono-scroll￿turbocharger￿assembly￿on￿the￿S58￿engine￿is￿the
MHI￿Group.
8.2.3.￿Electrical￿wastegate￿valve￿actuator
The￿S58￿engine￿uses￿an￿electric￿wastegate￿controller.￿The￿function￿of￿the￿electric￿wastegate￿controller
on￿the￿S58￿engine￿is￿the￿same￿as￿on￿the￿BMW￿AG￿engines.
The￿fundamental￿advantages￿of￿the￿electric￿wastegate￿controller￿are:
• High￿adjustment￿speed
• Precise￿charging￿pressure￿control
• High￿closing￿force,￿thus￿less￿leakage￿and￿quicker￿build-up￿of￿charging￿pressure
• Complete￿opening￿of￿the￿wastegate￿valve￿possible.￿This￿supports￿quick￿heating￿up￿with￿a￿cold
catalytic￿converter.
• Thus￿lower￿exhaust￿emissions
• Fuel￿economy
The￿electric￿wastegate￿controller￿is￿controlled￿directly￿by￿the￿DME￿control￿unit￿using￿a￿pulse-width
modulated￿(PWM)￿signal.
8.2.4.￿Catalytic￿converter
The￿S58￿engine￿has￿one￿close-to-engine￿catalytic￿converter￿per￿cylinder￿bank,￿each￿with￿a￿ceramic
monolith.
Explanation
Exhaust￿manifold,￿cylinders￿4-6
Wastegate￿valve,￿control￿rod,￿cylinders￿4-6
Oil￿feed￿line
Electrical￿wastegate￿valve￿actuator,￿cylinders￿4-6
Clean￿air￿feed,￿cylinders￿4-6
Exhaust￿manifold,￿cylinders￿1-3
Electrical￿wastegate￿valve￿actuator,￿cylinders￿1-3
Clean￿air￿feed,￿cylinders￿1-3
Connection￿for￿the￿charge￿air￿cooler,￿cylinders￿1-3
Coolant￿connections
Oil￿return
Wastegate￿valve,￿control￿rod,￿cylinders￿1-3
Connection￿for￿the￿exhaust￿system
Connection￿for￿the￿charge￿air￿cooler,￿cylinders￿4-6
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