Engine On Energy Management, Function - GF54.10-P-1060FG
Model 213 up to model year 2021
Function requirements in general
- Signal "engine running" set
The CDI control unit (N3/9) (diesel engine) or the ME-SFI control unit (N3/10) (gasoline engine) sends the signal "Engine running" via drive train CAN (CAN C1), drivetrain control unit (N127), chassis FlexRay (Flex E), electronic ignition lock control unit (N73) and interior CAN (CAN B) to the front SAM control unit (N10/6).
Engine on energy management, general
Engine on energy management ensures the stability of the on-board electrical system as well as an even charge balance in the on-board electrical system battery (G1).
If lots of electrical consumers are operated simultaneously, overload situations may occur, which have to then be buffered by the on-board electrical system battery. If such an overload situation lasts for an extended period or if the charging capacity of the on-board electrical system battery is low, a negative charge/discharge ratio could arise. In such an instance, the mobility and the stable supply of all electrical consumers can no longer be assured. If the on-board electrical system remains overloaded the engine ON energy management increases the power output of the alternator (G2) (except model 213.016/050/053/054/216 and except code B01 (48V technology)) or the energy transfer from the high-voltage on-board electrical system over the power electronics control unit (N129/1) (model 213.016/050/053/054/216) or the energy transfer from the 48 V on-board electrical system over the DC/DC converter control unit (N83/1) (with code B01 (48V technology)). The engine ON energy management also reduces the comfort consumers to enable an equalized charge balance for the on-board electrical system battery to be achieved.
Energy management for driving encompasses the following subfunctions:
- Voltage provision
- Dynamic idle speed control (except model 213.016/050/053/054/216 and except code B01 (48V technology))
- Consumer reduction (deactivation of comfort functions)
Model 213.016/050/053/054/216 up to model year 2021
To enable the "P" selector lever position to be engaged even when the on-board electrical system is overloaded, the electronic ignition lock control unit is also powered through the auxiliary battery of the ECO start/stop function (G1/13).
Model 213 with transmission 725 up to model year 2021
To enable selector lever position "P" to also be engaged when the on-board electrical system is overloaded, the electronic ignition lock control unit is also supplied with voltage through the park pawl capacitor (C8).
Voltage provision
The voltage provision function comprises the following subfunctions:
- Determination of charge level of on-board electrical system battery
- Charge on-board electrical system battery
- Alternator control (alternator management) (except model 213.016/050/053/054/216 and except code B01 (48V technology))
Determination of charge level of on-board electrical system battery
The state of the on-board electrical system battery is recorded by the battery sensor (B95).
The battery sensor calculates corresponding parameters by means of voltage, current and temperature measurements on the on-board electrical system battery. The charge level of the on-board electrical system battery is the ratio of the current charge to the maximum storable charge. This is based on the calculation of the internal resistance. This, along with the battery capacity, is then used to compute the charge stored in the on-board electrical system battery.
The front SAM control unit reads in the data of the battery sensor via the battery sensor LIN (LIN B15), measures the voltages at circuit 30 and circuit 30t and calculates the specified voltage from the alternator required to provide the requested power (except model 213.016/050/053/054/216 and except code B01 (48V technology)) or the required energy transfer from the high-voltage on-board electrical system via the power electronics control unit (model 213.016/050/053/054/216) or the required energy transfer from the 48 V on-board electrical system via the DC/DC converter control unit (with code B01 (48V technology)).
Charge on-board electrical system battery
Charging of the on-board electrical system battery requires that the specified voltage be determined. The specified voltage is the voltage that must be present at the terminals of the on-board electrical system battery in order to charge the on-board electrical system battery in an optimum manner. Depending on various factors, the specified voltage is determined using the alternator management (except model 213.016/050/053/054/216 and except code B01 (48V technology)) or the energy transfer required from the high-voltage on-board electrical system through the power electronics control unit (model 213.016/050/053/054/216) or the energy transfer required from the 48 V on-board electrical system through the DC/DC converter control unit (with code B01 (48V technology)) or using the temperature-dependent charging characteristic. After starting the engine, rapid charging at high voltage is conducted (except CODE U98 (LITHIUM-ION STARTER BATTERY (LISB))), until a sufficiently high charge level on the on-board electrical system battery is detected.
Model 213
up to model year 2021
except code U98 (LITHIUM-ION STARTER BATTERY (LISB))
Rapid charging occurs with a charging voltage of 15 V and can last from 20 s to 1 h. It is only following this step that a temperature-dependent characteristic or alternator management is used (except model 213.016/050/053/054/216 and except code B01 (48V technology)).
Alternator management (except code B01 (48V technology)) includes lowering the charging voltage to 12.8 V and the possibility of recuperation when the engine is in overrun mode. When the alternator management is active, one of the front doors is open and the vehicle speed is 0 km/h, the alternator management changes to the jump start mode. At the same time, the alternator voltage is increased constantly to 14.3 V. This jump-start is only canceled when the vehicle speed is greater than 0 km/h. An emergency shutoff is activated when driving down long hills in order to avoid overcharging of the on-board electrical system battery resulting from long periods of deceleration fuel shutoff. This emergency shutoff deactivates regenerative braking in cases of high voltage combined with low power consumption. If the on-board electrical system battery becomes fully charged (for example after driving in the cold or long downhill travel), the voltage is lowered further to return the battery to its optimum charge level of 80%. On model 213.016/050/053/054/216 the on-board electrical system battery is charged using energy from the high-voltage on-board electrical system. To this end, the energy stored in the high-voltage battery (A100g1) is fed by the power electronics control unit to the 12 V on-board electrical system. The front SAM control unit supports this by sending information on the on-board electrical system capacity via the interior CAN, electronic ignition lock control unit, chassis FlexRay, powertrain control unit and hybrid CAN (CAN L) to the power electronics control unit.
On vehicles with code B01 (48V technology) the on-board electrical system battery is charged with energy from the 48 V on-board electrical system. To this end, the energy stored in the 48 V on-board electrical system is fed by the DC/DC converter control unit to the 12-V on-board electrical system. The front SAM control unit sends information on the on-board electrical system capacity utilization over the interior CAN to the DC/DC converter control unit.
Voltage provision
Rapid charging (except CODE U98 (LITHIUM ION STARTER BATTERY (LISB))):
- Voltage up to 15 V
- Once after terminal 50 ON
- Optimized charging of on-board electrical system battery, incl. during short trips
- Duration 20 s to 1 h
- Rapid charging ends when the charge of the on-board electrical system battery is at least 80 %
- No rapid charging with trailer operation (with CODE 550 (Trailer hitch))
- No quick charging when the on-board electrical system battery is too warm
Temperature-based charging:
- Temperature of on-board electrical system battery below 20°C
- Outside temperature below 20°C
- Rapid charging (except CODE U98 (LITHIUM ION STARTER BATTERY (LISB))) finished, alternator management not possible
- Voltage range 13.5 to 15 V
- Linear charging characteristic (temperature-dependent)
Transition to alternator management (except model 213.016/050/053/054/216 and except code B01 (48V technology)):
- Rapid charging (except CODE U98 (LITHIUM ION STARTER BATTERY (LISB))) finished
- Stable engine operation
- Temperature of on-board electrical system battery above 20°C
- Outside temperature above 20°C
- Charge level of the on-board electrical system battery at least 80 %
- No trailer operation (with code 550 (Trailer hitch))
Alternator management (except model 213.016/050/053/054/216 and except code B01 (48V technology)):
- Voltage 12.8 V, with some exterior lamp functions 13.5 V
- Charge level of the on-board electrical system battery at least 80 %
- Reduced consumer power consumption
- With air conditioning ON and high blower setting 14.3 V
Transition to charging in deceleration mode:
- Stable engine operation
- CDI control unit or ME [ME-SFI] control unit detects deceleration mode
Charging in deceleration mode:
- Voltage up to 15 V
- Activated by CDI control unit or ME-SFI control unit
- On-board electrical system battery charged when "free" energy is available
Alternator control (alternator management) (except model 213.016/050/053/054/216 and except code B01 (48V technology))
Alternator regulation (alternator management):
- Takes place in the CDI control unit or ME-SFI [ME] control unit.
- Sets the specified voltage of the energy management.
- Switches to regenerative braking voltage in deceleration mode.
- Sets a lower voltage in exceptional cases (e.g. stall prevention, cold start at high altitude, catalytic converter heating).
The alternator control actuates the alternator's power output. The CDI control unit or the ME-SFI control unit communicates with the alternator via the drive train LIN (LIN C1) and evaluates the alternator operating rate. The CDI control unit or the ME-SFI [ME] control unit sends information on alternator capacity over the drive train CAN, drivetrain control unit, chassis FlexRay, electronic ignition lock control unit and the interior CAN to the front SAM control unit.
The state of the on-board electrical system battery is recorded by the battery sensor. The battery sensor sends corresponding parameters for the on-board electrical system battery over the battery sensor-LIN to the front SAM control unit. The front SAM control unit evaluates all of the relevant information and calculates the specified voltage required for the alternator. The front SAM control unit then sends this value to the CDI control unit or the ME-SFI control unit via interior CAN, electronic ignition lock control unit, chassis FlexRay, drivetrain control unit and drive train CAN. The CDI control unit or the ME-SFI [ME] control unit evaluates this, taking additional input factors (e.g. A/C ON) into consideration, and calculates the ideal specified voltage for the alternator. The CDI control unit or the ME-SFI [ME] control unit then calculates the alternator specified voltage via drive train LIN to the alternator, which then sets it. In addition, the CDI control unit or ME-SFI [ME] control unit checks the input factors for plausibility in order to rule out any overcharging or faulty charging of the on-board electrical system battery.
The CDI control unit or the ME-SFI control unit compares the optimum specified voltage for the alternator with the actual alternator power and is thus able to determine the energy state of the on-board electrical system. The continuous comparison of these two values and the corresponding corrections are designated as power management. As soon as it becomes apparent that the on-board electrical system voltage is not high enough, the power management is gradually reduced. The alternator can then make its full output available.
The power management function in the CDI control unit or in the ME-SFI control unit adopts the alternator specified voltage values for the front SAM control unit as guideline values only, because certain vehicle conditions (e.g. engine comfort, idle stability, engine start and irregular engine operation) have to be taken into consideration. The actual specified voltage of the alternator is therefore obtained by overlaying the energy management with the alternator specified voltages sent by the front SAM control unit.
If a fault is found on the battery sensor, the energy management switches to a fixed voltage of 14.3 V. This behavior can also be activated using a diagnosis service in order to check the alternator, for example.
Dynamic idle speed control (except model 213.016/050/053/054/216 and except code B01 (48V technology))
Dynamic idle speed control sets the engine's idle speed such that no current needs to be drawn from the on-board electrical system battery when the vehicle is idling. The idle speed is increased for a higher consumer load. Idle speed increase is performed as a preventive measure. In other words, the system does not respond to a lack of electrical energy, but rather sets the required idle speed based on the present load.
The following factors are used for dynamic idle speed control computations:
- Alternator excitation current
- Alternator operating rate
- On-board electrical system battery voltage
- On-board electrical system battery current
- State of on-board electrical system battery
- Engine speed
- Consumer reduction shutoff stage
- Engine start
The CDI control unit or the ME-SFI control unit communicates with the alternator via the drive train LIN and evaluates the alternator operating rate.
The CDI control unit or the ME-SFI [ME] control unit sends the "Engine running" signal and information on alternator capacity via drive train CAN, drivetrain control unit, chassis FlexRay, electronic ignition lock control unit and the interior CAN to the front SAM control unit.
The state, voltage and current of the on-board electrical system battery are detected by the battery sensor. The battery sensor sends corresponding parameters for the on-board electrical system battery over the battery sensor-LIN to the front SAM control unit. The front SAM control unit evaluates all relevant information and computes the energy required. If the energy requirement cannot be covered by the alternator management, the idle speed is increased. The maximum possible excitation current is calculated from the current excitation current and the alternator utilization. The maximum possible excitation current is used to calculate the maximum possible alternator current at different idle speeds. The front SAM control unit sends corresponding requests over the interior CAN, electronic ignition lock control unit, chassis FlexRay, drivetrain control unit and drive train CAN to the CDI control unit or the ME-SFI [ME] control unit, which then raises the idle speed accordingly.
The idle speed increase is reversed under the following circumstances:
- Engine off or alternator defective
- Simultaneous occurrence of the following conditions:
- Consumer reduction not active
- Consumer load no longer high
Consumer reduction (deactivation of comfort functions)
If the required electrical power is no longer available, the load on the on-board electrical system is reduced by cutting back comfort functions. This serves to avoid any significantly negative charge balance for the on-board electrical system battery. This in turn retains the engine's starting capability. The comfort functions are reactivated when the required electrical power to stabilize the on-board electrical system voltage is available again.
Detailed information on evaluation of alternator operating rate can be found in the section "Alternator regulation".
When the on-board electrical system voltage drops to less than 12.2 V (except code U98 (LITHIUM-ION STARTER BATTERY (LISB))) or when the maximum discharge current is reached (with code U98 (LITHIUM-ION STARTER BATTERY (LISB))), the consumer reduction is activated. The first consumer's power consumption is reduced 20 s after engine start. If the cutback conditions remain unchanged, the power consumption of one further consumer will be reduced every following second.
The front left reversible emergency tensioning retractor (A76) and the front right reversible emergency tensioning retractor (A76/1) have very high starting and operating currents. The power consumption of some high power consumers is therefore reduced or the consumers are shut off completely as quickly as possible for approx. 2 s when the reversible emergency tensioning retractors are triggered in order to reduce the load on the on-board electrical system.
The front SAM control unit sends the request to limit power or to shut down consumers over the interior CAN to the control units that are connected to the interior CAN, and over the interior CAN, electronic ignition lock control unit and suspension FlexRay to the steering column tube module control unit (N80), and over the interior CAN, electronic ignition lock control unit, suspension FlexRay, powertrain control unit and powertrain CAN to the CDI control unit or ME-SFI [ME] control unit.
The "De-icing" shutoff sequence (less than 10 min) is included in the following table. A switch is then made to the "Comfort" shut-off sequence.
| Sequence | Power-reduced or deactivated function | Responsible control unit |
|---|---|---|
| 1 | PTC heater booster (R22/3), 1st branch, heat boosting (model 213 with engine 654, 642 or 274 with code 401 (Seat climate control for driver and front passenger) or code 824 (Additional parts for cold countries) or code 873 (Seat heater for driver and front passenger) or code 902 (Seat heating Plus for driver and front passenger) except code 228 (Stationary heater) or code 913 (Hot country code) or model 213.016/050/053/054/216) | Climate control, control unit (N22/1) |
| 2 | PTC heater booster (R22/3), 2nd branch, heat boosting (model 213 with engine 654, 642 or 274 with code 401 (Seat climate control for driver and front passenger) or code 824 (Additional parts for cold countries) or code 873 (Seat heater for driver and front passenger) or code 902 (Seat heating Plus for driver and front passenger) except code 228 (Stationary heater) or code 913 (Hot country code) or model 213.016/050/053/054/216) | Climate control, control unit (N22/1) |
| 3 | PTC heater booster (R22/3), 3rd branch, heat boosting (model 213 with engine 654, 642 or 274 with code 401 (Seat climate control for driver and front passenger) or code 824 (Additional parts for cold countries) or code 873 (Seat heater for driver and front passenger) or code 902 (Seat heating Plus for driver and front passenger) except code 228 (Stationary heater) or code 913 (Hot country code) or model 213.016/050/053/054/216) | Climate control, control unit (N22/1) |
| 4 | PTC heater booster (R22/3), 4th branch, heat boosting (model 213 with engine 654, 642 or 274 with code 401 (Seat climate control for driver and front passenger) or code 824 (Additional parts for cold countries) or code 873 (Seat heating for driver and front passenger) or code 902 (Seat heating Plus for driver and front passenger) except code 228 (Stationary heater) or code 913 (Hot country code) or model 213.016/050/053/054/216) | Climate control, control unit (N22/1) |
| 5 | PTC heater booster (R22/3), 5th branch, heat boosting (model 213 with engine 654, 642 or 274 with code 401 (Seat climate control for driver and front passenger) or code 824 (Additional parts for cold countries) or code 873 (Seat heating for driver and front passenger) or code 902 (Seat heating Plus for driver and front passenger) except code 228 (Stationary heater) or code 913 (Hot country code) or model 213.016/050/053/054/216) | Climate control, control unit (N22/1) |
| 6 | PTC heater booster (R22/3), 6th branch, heat boosting (model 213 with engine 654, 642 or 274 with code 401 (Seat climate control for driver and front passenger) or code 824 (Additional parts for cold countries) or code 873 (Seat heater for driver and front passenger) or code 902 (Seat heating Plus for driver and front passenger) except code 228 (Stationary heater) or code 913 (Hot country code) or model 213.016/050/053/054/216) | Climate control, control unit (N22/1) |
| 7 | Seat heater stage 3 (with CODE 401 (Seat climate control for driver and front passenger) or CODE 873 (Seat heater for driver and front passenger)) | Rear SAM control unit (N10/8) |
| 8 | Seat heater stage 2 (with CODE 401 (Seat climate control for driver and front passenger) or CODE 873 (Seat heater for driver and front passenger)) | Rear SAM control unit (N10/8) |
| 9 | Steering wheel heater (with CODE 443 (Steering wheel heater)) | Steering column tube module control unit (N80) |
| 10 | Rear blower 50 % (with code 581 (Automatic air conditioning)) | Climate control, control unit (N22/1) |
| 11 | Front blower 50 % | Climate control, control unit (N22/1) |
| 12 | Fan 50 % | CDI control unit (N3/9) (diesel engine) or ME-SFI [ME] control unit (N3/10) (gasoline engine) |
| 13 | Trunk socket, cigarette lighter (with CODE 301 (Smoker package)) | Front SAM control unit (N10/6) |
| 14 | Mirror heater | Left front door control unit (N69/1) and right front door control unit (N69/2) |
| 15 | Spray nozzle hose heater (with CODE 875 (Heated windshield washer system)) | Front SAM control unit (N10/6) |
| 16 | Rear window heater | Rear SAM control unit (N10/8) |
| 17 | Seat heater stage 1 (with code 401 (Seat climate control for driver and front passenger) or code 873 (Seat heater for driver and front passenger)) | Rear SAM control unit (N10/8) |
| 18 | Seat ventilation (with CODE 401 (Seat climate control for driver and front passenger)) | Rear SAM control unit (N10/8) |
The shutoff sequence "Comfort" is shown in the table below.
| Sequence | Power-reduced or deactivated function | Responsible control unit |
|---|---|---|
| 1 | PTC heater booster (R22/3), 1st branch, heat boosting (model 213 with engine 654, 642 or 274 with code 401 (Seat climate control for driver and front passenger) or code 824 (Additional parts for cold countries) or code 873 (Seat heater for driver and front passenger) or code 902 (Seat heating Plus for driver and front passenger) except code 228 (Stationary heater) or code 913 (Hot country code) or model 213.016/050/053/054/216) | Climate control, control unit (N22/1) |
| 2 | PTC heater booster (R22/3), 2nd branch, heat boosting (model 213 with engine 654, 642 or 274 with code 401 (Seat climate control for driver and front passenger) or code 824 (Additional parts for cold countries) or code 873 (Seat heater for driver and front passenger) or code 902 (Seat heating Plus for driver and front passenger) except code 228 (Stationary heater) or code 913 (Hot country code) or model 213.016/050/053/054/216) | Climate control, control unit (N22/1) |
| 3 | PTC heater booster (R22/3), 3rd branch, heat boosting (model 213 with engine 654, 642 or 274 with code 401 (Seat climate control for driver and front passenger) or code 824 (Additional parts for cold countries) or code 873 (Seat heater for driver and front passenger) or code 902 (Seat heating Plus for driver and front passenger) except code 228 (Stationary heater) or code 913 (Hot country code) or model 213.016/050/053/054/216) | Climate control, control unit (N22/1) |
| 4 | PTC heater booster (R22/3), 4th branch, heat boosting (model 213 with engine 654, 642 or 274 with code 401 (Seat climate control for driver and front passenger) or code 824 (Additional parts for cold countries) or code 873 (Seat heating for driver and front passenger) or code 902 (Seat heating Plus for driver and front passenger) except code 228 (Stationary heater) or code 913 (Hot country code) or model 213.016/050/053/054/216) | Climate control, control unit (N22/1) |
| 5 | PTC heater booster (R22/3), 5th branch, heat boosting (model 213 with engine 654, 642 or 274 with code 401 (Seat climate control for driver and front passenger) or code 824 (Additional parts for cold countries) or code 873 (Seat heating for driver and front passenger) or code 902 (Seat heating Plus for driver and front passenger) except code 228 (Stationary heater) or code 913 (Hot country code) or model 213.016/050/053/054/216) | Climate control, control unit (N22/1) |
| 6 | PTC heater booster (R22/3), 6th branch, heat boosting (model 213 with engine 654, 642 or 274 with code 401 (Seat climate control for driver and front passenger) or code 824 (Additional parts for cold countries) or code 873 (Seat heater for driver and front passenger) or code 902 (Seat heating Plus for driver and front passenger) except code 228 (Stationary heater) or code 913 (Hot country code) or model 213.016/050/053/054/216) | Climate control, control unit (N22/1) |
| 7 | Windshield heater (with code 597 (Windshield, heated)) P = 50 % | Climate control, control unit (N22/1) |
| 8 | Spray nozzle hose heater (with CODE 875 (Heated windshield washer system)) | Front SAM control unit (N10/6) |
| 9 | Mirror heater | Left front door control unit (N69/1) and right front door control unit (N69/2) |
| 10 | Seat heater stage 3 (with CODE 401 (Seat climate control for driver and front passenger) or CODE 873 (Seat heater for driver and front passenger)) | Rear SAM control unit (N10/8) |
| 11 | Rear window heater | Rear SAM control unit (N10/8) |
| 12 | Steering wheel heater (with CODE 443 (Steering wheel heater)) | Steering column tube module control unit (N80) |
| 13 | Seat heater stage 2 (with CODE 401 (Seat climate control for driver and front passenger) or CODE 873 (Seat heater for driver and front passenger)) | Rear SAM control unit (N10/8) |
| 14 | Rear blower 50 % (with code 581 (Automatic air conditioning)) | Climate control, control unit (N22/1) |
| 15 | Front blower 50 % | Climate control, control unit (N22/1) |
| 16 | Fan 50 % | CDI control unit (N3/9) (diesel engine) or ME-SFI [ME] control unit (N3/10) (gasoline engine) |
| 17 | Trunk socket, cigarette lighter (with CODE 301 (Smoker package)) | Front SAM control unit (N10/6) |
| 18 | Windshield heater (with code 597 (Windshield, heated)) P = 0 % | Climate control, control unit (N22/1) |
| 19 | Seat heater stage 1 (with code 401 (Seat climate control for driver and front passenger) or code 873 (Seat heater for driver and front passenger)) | Rear SAM control unit (N10/8) |
| 20 | Seat ventilation (with CODE 401 (Seat climate control for driver and front passenger)) | Rear SAM control unit (N10/8) |
When the on-board electrical system voltage has been stabilized to a value above 13.5 V or when the permissible discharge current is undershot, power output limitation or consumer shutdown is canceled in the reverse order with a waiting time between each of 1 s. The on-board electrical system emergency mode represents a special case of consumer reduction. This is activated by the energy management in the front SAM control unit if the voltage of the on-board electrical system battery remains below a defined voltage threshold for a certain period of time. The energy management uses all options available through dynamic power management to enforce a positive charge balance.
If the on-board electrical system voltage drops below 10.6 V for longer than 10 s, the front SAM control unit activates the on-board electrical system emergency mode function.
This causes the activation of the following engine on energy management functions:
- Idle speed increase
- Deactivation of alternator management
- Consumer reduction with shutoff of short-term consumers Unlike consumer reduction, power output limitation or consumer shutoff is done with a cycle time of 200 ms.
As soon as the on-board electrical system voltage has stabilized to a value of 11.8 V for 10 s or a change in circuit status from circuit 15R to circuit 15C has occurred, the front SAM control unit ends the on-board electrical system emergency mode function. Consumer output limitation or deactivation is canceled.
| Electrical function schematic for dynamic idle speed increase | Model 213 (except 213.016/050/053/054/216) up to model year 2021 except code B01 (48V technology) | PE54.10-P-2063-97DBA | |
| Electrical function schematic for alternator management | Model 213 (except 213.016/050/053/054/216) up to model year 2021 except code B01 (48V technology) | PE54.10-P-2064-97DBA | |
| Electrical function schematic for comfort function shutoff | PE54.10-P-2076-97DBA | ||
| Overview of energy management system components | GF54.10-P-9990FG |