Electrical vehicle, function

D08.00-A014-79

 The interlock circuit and high-voltage on-board electrical system are not shown in the block diagram.

 Interlock circuit
The interlock circuit is used as contact protection to protect people against inadvertent contact with high-voltage components. The interlock is an anticipatory contact, which opens a little before the high-voltage connection when disconnecting a high-voltage connection. In this way timely discharging of the high voltage intermediate circuit is achieved by the control units of the high-voltage components.
The interlock circuit detects open lines or access points in the high-voltage on-board electrical system. For this purpose, a 12-V/88 Hz interlock signal is looped through all component parts of the high-voltage on-board electrical system that can be removed or opened. To do this, there is a jumper in each removable high-voltage plug connection which interrupts the interlock circuit when the high-voltage plug connection is detached.

 Further information on the interlock circuit and high-voltage on-board electrical system can be found in the separate function description "High-voltage on-board electrical system function".

Function description for the electric vehicle, general points

The electric vehicle function description includes the control and monitoring of the electric machine 1 (A79/1) and of the high-voltage on-board electrical system. The master control unit is the powertrain control unit (N127), which contains the energy management and this coordinates all energy influences and torques in the electric vehicle.

The electric vehicle is driven exclusively by an electric machine. The electrical energy for this is provided by 3 lithium-ion high-voltage batteries that are switched at the same time, which were supercharged previously via the AC charger for the high-voltage battery (N83/15) during steady-state charging.

The high-voltage batteries have a maximum capacity of 41.4 kWh. To optimize the longevity of the performance of the battery pack, 35.2 kWh is available for the operating status. The electric vehicle can be charged at a mains socket, a public charging station, or a wallbox charging station. When charging at a mains outlet, the charging current must be limited if necessary to ensure that the local power network is not overloaded.

 Further information on the charging of the high-voltage batteries can be found in the separate function description "Stationary charging function".

The document includes in detail the following information:

 Electric drive

 High-voltage on-board electrical system

 Energy management

 Drive programs "C", "E", "E+"

 Speed limit

 Occupancy detection

 Towing and reversing

Electric drive

The electric drive consists of the electric powertrain, to which the electric machine 1, the transmission as well as the power electronics control unit belong.

 Further information is contained in the separate function description "electric drive function" and "electric motor component description."

High-voltage on-board electrical system

The high-voltage on-board electrical system describes both the charging of the high-voltage batteries and the monitoring, cooling, and networking of the high voltage components.

 Further information can be found in the separate function descriptions "Stationary charging function" and "High-voltage on-board electrical system cooling function".

Energy management

High-voltage on-board electrical system energy management manages the provision (supply) and consumption (balance) of electrical energy.

 Further information can be found in the separate function description "High-voltage on-board electrical system function".

D08.00-A017-76

Drive programs "C", "E", "E+"

3 different drive programs are available. At the start, the base drive program "E" (Economy) is active.

The two programs "C" (Comfort) and "E+" (Economy Plus) can be selected via the drive program button (S2/2s2) in the instrument panel.

In the multifunction display of the instrument cluster, the selected drive program is shown on the bottom right.

The drive programs have different features in the mileage, in the response time of the accelerator pedal, and in the heating and climate control output. Considered together, these features can lead to different ranges of the vehicle.

The range can be optimized via the drive program "E+". For this purpose, the maximum output of electric machine 1 is throttled at 70 kW and 270 Nm. The heating and climate control components for the driver's cab are controlled energy-consciously depending on the vehicle exterior temperature and vehicle interior temperature to achieve the best possible range. Because of the reduced heating output, a low blower setting should be selected consciously. The response time of the accelerator pedal is delayed so that sharp acceleration is prevented.

For all three drive programs, a defrost function is ensured for the windows. The individual drive programs have the following further features:

"C" ("Comfort") drive program

 The entirety of the available performance can be accessed via the accelerator pedal module.

 Controllability in the vehicle speed range is improved.

"E" ("Economy") drive program

 Except at full load, the vehicle starts off forwards more smoothly.

 Reduced performance at the accelerator pedal module increased controllability. This supports an even and energy-optimized driving style.

 The wheels do not spin as easily when accelerating.

 Full output only when using the kickdown.

"E+" ("Economy Plus") drive program

 Reduced torque, speed reduction and greatly reduced output. A particularly efficient and uniform driving style is thus supported.

 Except at full load, the vehicle starts off forwards more smoothly.

 The wheels do not spin as easily when accelerating.

 Particularly efficient overrun mode.

 Full output only when using the kickdown.

 The output of the A/C and heater is reduced.

 The drive program "Comfort" can optionally be deactivated ex works (with code E1P (Comfort drive program deactivated)). Here, with comfort limitation in the heating and climate control output, an optimum range of the vehicle is ensured. Where "C" is selected via the drive program button, the permanent deactivation is indicated to the driver in the instrument cluster.

Speed limit

The eSprinter has as standard a speed limitation of 80 km/h. The speed limitations 100 km/h and 120 km/h are optionally available, suitable for the respective application.

A max. speed of 80 km/h fulfills all requirements in urban traffic and in conurbations; at the same time, it conserves energy and increases the range. Speeds up to 120 km/h are possible if a higher speed is required.

If the vehicle is limited to a maximum speed of 120 km/h,  driving downhill on the freeway, for example, may cause the maximum approved speed to be exceeded due to the dead weight.

To prevent damage to the electrical powertrain, a message is displayed in the multifunction display of the instrument cluster indicating "Maximum speed reached, reduce speed" (not display text). A warning tone also sounds. When this message is displayed, the vehicle must be braked actively.

Occupancy detection

Occupancy detection is an important safety feature with e­mobility. Because the vehicle is so quite at a standstill, it can occur that the driver leaves the vehicle unintentionally while it is still ready to drive.

Fundamentally, a ready-to-drive vehicle is indicated in the multifunction display of the instrument cluster via the "READY" display. The seat belt buckle and the driver's door are controlled via the security system. As soon as the driver opens the seat belt buckle or the driver's door, a warning tone sounds and a message appears in the multifunction display. If the selector position "P" has not yet been set in the transmission when opening the driver's door, it is set automatically.

Towing and reversing

 It is not permissible to tow the vehicle if the key cannot be turned in the ignition lock.
The steering wheel locking is engaged then and the vehicle cannot be steered. There is a risk of accident!

 It is not permissible to tow another vehicle with the electric vehicle.
The electric drive or a high-voltage component can otherwise be damaged.

 When towing with a tow rope or a tow bar, the ignition must always be switched on.
The electric vehicle must be transported on a transporter or trailer if the drive system is malfunctioning or defective or the energy supply or on-board electrical system are malfunctioning.
In this case, the servo support would be missing for the steering and the brake. The driver must then apply significantly more power when steering or braking.

 When towing, observe the legal regulations in the individual countries.

In the case of towing with both axles on the ground, the engine start/stop button (S2/2) must be actuated x 2 beforehand without actuating the brake pedal.

The on-board electrical system battery (G1) must be clipped on and charged. It will otherwise not be possible to move the transmission to "N" position. Otherwise, the electric vehicle must be transported on a transporter or trailer.

Before towing, automatic door locking must be switched off, otherwise there is a risk that you could be locked out when pushing or towing the vehicle.

Towing is only permissible forwards in the direction of travel. Towing backwards is not permissible due to negative effects on the oil supply. Reversing is permissible up to 23 km/h for a maximum of 3 min. Above this, missing lubrication may cause the electrical drivetrain to fail.

The vehicle may be towed for a max. distance of 50 km. In this connection, a towing speed of 50 km/h may not be exceeded. For a towing distance greater than 50 km, the entire vehicle must be lifted off the road and transported.

It is not permissible to tow the vehicle with a raised rear axle!

In the following cases, the vehicle must not be towed with even the drive axle on the ground:

 If the drive system cannot be switched on.

 If the multifunction display of the instrument cluster displays a towing prohibition when the drive system is switched on.

 If the engine cooling system is damaged or leaky.

Otherwise, the drive system may be damaged.

 If the inclination of the vehicle changes when tow-away protection is switched on, an optical and an acoustic alarm are triggered.
If the vehicle is lifted on one side, for example, this could be the case. For this reason, the tow-away protection should be deactivated.