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Home >> Mercedes Benz >> 2007 >> CL600 >> Repair and Diagnosis (Single Page) >> Electrical >> Charging Systems >> Battery, Collision Avoidance, Control Modules/Units, Displays, & Fuse/Relay Assignment -- Basic Knowledge -- Cl600 (216.376) >> Basic Knowledge >> Energy management, function - GF54.10-P-0003LE

Energy management, function - GF54.10-P-0003LE

MODEL 216.3, 221.0 /1 as of model year 2009 /YoM 08 

Function requirements, general 

Energy management, general 

Energy management manages the provision and consumption of electrical energy with the aim of ensuring the startability of the engine and a stable supply to all electrical consumers.

IMPORTANT In the energy management system, only the low-voltage network (12 V) is described. For hybrid cars, the correlation between high-voltage and low-voltage networks is also described.

A detailed description of the high-voltage network is provided in the function description of the hybrid drive systems.

Energy management is accomplished using the following subfunctions:

Further subfunctions are described in separate documents:

IMPORTANT Depending on the engine mounted in the vehicle, either the CDI control unit (N3/9) (with diesel engine) or the ME-SFI [ME] control unit (N3/10) (with gasoline engine) is installed.

Alternator actuation, function 

Control of the alternator (G2) is performed according to the requests made by the CDI control unit or the ME-SFI [ME] control unit.

The CDI control unit or the ME-SFI [ME] control unit calculates the specified voltage values using the specified values from the on-board electrical system. The alternator is controlled on the basis of this calculation. Communication with the alternator and requests to it take place via the drive LIN (LIN C1).

IMPORTANT The CDI control unit or the ME-SFI [ME] control unit is active as the master control unit for the alternator.

On model 221.095/195, the alternator is only activated if the energy provided by the DC/DC converter control unit (N83/1) from the high-voltage on-board electrical system is not sufficient.

Energy management, function 

The energy management system monitors the capacity of the onboard electrical system and actively intervenes in balancing energy requirements. The aim is to ensure a stable power supply for the electrical consumers in the 12 V on-board electrical system. The following components are involved in energy management:

The energy requirements of all electrical consumers are defined based on the state of the on-board electrical system battery, which is permanently monitored by the battery sensor. The battery sensor uses various voltage, current and temperature measurements to compute parameters that serve as the basis for energy management. Energy management influences the power output of the alternator or of the DC/DC converter control unit such as to achieve a balanced, positive charge/discharge ratio in the on-board electrical system battery and provide for fuel-efficient operation of the vehicle.

IMPORTANT Model 221.095/195:

The 12 V on-board electrical system is supplied with energy primarily via the DC/DC converter control unit. Energy is supplied to the 12 V on-board electrical system via the DC/DC converter control unit as follows:

If the energy provided by the DC/DC converter control unit cannot cover the power requirement, the alternator is activated as an auxiliary power source.

Energy transfer of high-voltage/low-voltage on-board electrical system, function (model 221.095/195) 

Because of the hybrid drive used, the vehicle is equipped with an additional high-voltage on-board electrical system (U = 140 V).

The energy management module in the ME-SFI [ME] control unit regulates the energy flows in the high-voltage on-board electrical system along with the voltage conversion and energy exchange from and to the 12 V on-board electrical system.

In addition, the ME-SFI [ME] control unit communicates with the DC/DC converter control unit via the drive train sensor CAN (CAN I) and with the alternator via the drivetrain LIN.

The 12 V on-board electrical system is supplied with energy primarily from the high-voltage on-board electrical system "buck mode".

For this purpose, energy is supplied to the 12 V on-board electrical system via the DC/DC converter control unit as follows:

In the case of extremely low outside temperatures, the 12 V onboard electrical system may assist the high-voltage on-board electrical system via the DC/DC converter control unit in order to ensure the starting ability of the engine "boost mode".

IMPORTANT The following components are involved in the high-voltage energy management:

Energy management, location of components   GF54.10-P-0003-01LE 
Energy management, block diagram   GF54.10-P-0003-02LE 
Engine off energy management, function   GF54.10-P-1050LE 
Engine on energy management, function   GF54.10-P-1060LE 
Engine start/stop automatic function For code (B03) ECO Start-stop function GF54.10-P-1070LE 
DC/AC converter function Model 221 with code (U80) 115V power outlet GF54.10-P-2005LE
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