48V Alternator Bmw 3.0 d Mild Hybrid

The code BMW 12318490539 identifies a 48 V starter-generator for BMW mild hybrid systems, listed in the BMW parts catalog as “RP starter motor generator 48V”.

Technically it is driven by the accessory belt and can operate both as an electric generator and as an electric motor supporting the internal combustion engine. It is used on BMW vehicles equipped with Mild Hybrid Electric Vehicle systems and six-cylinder diesel engines from the B57 family.

Technical specifications

• Nominal voltage: 48 V.
• Nominal current: 210 A.
• Component type: starter-generator driven by the accessory belt for a mild hybrid system.
• Original equipment manufacturer: SEG Automotive.
• Poly-V belt pulley.
• Pulley groove count: 8.
• Pulley diameter: approximately 54 mm.
• Component electronically managed and integrated into the vehicle's 48 V MHEV network.

DIPA can perform overhauls on these components thanks to its experience and expertise.

Functions

• Generates electrical energy for the 48 V MHEV network during operation of the internal combustion engine.
• Recovers energy during deceleration and coasting, contributing to recharging the 48 V battery.
• Supports restarting the internal combustion engine in Start&Stop strategies.
• Can provide electric assist to the internal combustion engine during starting and acceleration.
• Works together with the 48 V battery, the DC/DC converter and the vehicle's energy management control units.
• Contributes to reduced fuel consumption and improved drive smoothness during Stop&Start and energy recovery phases.

Model applications

• BMW 3 Series/4 Series/5 Series/7 Series/X3/X4/X5/X6/X7

Common faults

• 48 V network charging fault or reduced energy recovery capacity.
• Fault messages related to the mild hybrid system, energy management or the 48 V battery.
• Start&Stop function not available or irregular engine restarts.
• Reduced or absent electric assistance to the internal combustion engine.

Final conclusions

The code BMW 12318490539 identifies a 48 V, 210 A MHEV starter-generator intended for BMW mild hybrid systems with B57 diesel engines. It should not be considered a standard 12 V alternator, as it actively participates in 48 V energy management, energy recovery, Start&Stop functions and electric assistance to the internal combustion engine.

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