LEMON Manuals: Even more car manuals for everyone
Home >> Smart >> 2016 >> Fortwo Proxy, Standard Trans >> Repair and Diagnosis >> Electrical >> Charging Systems >> Electrical Drive System - 453 Chassis >> Basic Knowledge >> Electrical Vehicle, Function - GF08.00-P-0002KJE

Electrical Vehicle, Function - GF08.00-P-0002KJE

ENGINE 780 in MODEL 453.091/391/491 

IMPORTANT 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 opening 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.

To do this, a 12 V/88 Hz interlock signal is looped through all high-voltage on-board electrical system components that can be removed or opened. To do this, there is an electrical bridge in each removable high-voltage connection which interrupts the interlock circuit during removal of the high-voltage connection.

The interlock circuit and the high voltage on-board electrical system are not shown in the following block diagram. Information about the interlock circuit and high-voltage on-board electrical system can be found in the document:

G12094474Courtesy of MERCEDES-BENZ USA
G12094475Courtesy of MERCEDES-BENZ USA
Sales designation Model Motor Transmission Notes
Smart for four electric drive 453.091 780.9 Single stage transmission with integral bevel gear differential Electric vehicle
Smart for four electric drive 453.391 780.9 Single stage transmission with integral bevel gear differential Electric vehicle
Smart for four electric drive 453.491 780.9 Single stage transmission with integral bevel gear differential Electric vehicle

Function description for the electric vehicle, general points 

The function description for the electric vehicle includes controlling and monitoring of the electric vehicle drive motor (M5) and the high voltage on-board electrical system. The master control unit is the EDCU (N127), which contains the energy management and therefore coordinate all energy flows and torques in electric vehicle.

The electric vehicle is exclusively driven by an electric motor. The electrical energy for this is made available by the high-voltage battery, which was previously charged via the charger control unit for the high-voltage battery (7 kW charger) (N83/5) or the charger control unit for the high-voltage battery (22 kW charger) (N83/10) during stationary charging.

The steady-state charging can take place here over the following 3 ways:

Further information about this can be found in the document:

ECO mode transmission mode 

The driver has the option of selecting the ECO mode transmission mode over operation of the Economy mode switch (S6/10). The center SAM control unit transmits the status of the Economy mode switch via the interior CAN to the EDCU, which implements the selected transmission mode. The letter of the selected transmission mode is shown to the driver in the IC. The Economy transmission mode is always active when switching on the ignition. The ECO mode is designed to enable the most economical driving style. This includes limiting the type-related maximum speed, adaptation of the accelerator pedal characteristic as well as fixed setting of the maximum regenerative braking stage. There is also an acceleration boost as a time-limited function which is triggered by the kickdown functionality of the accelerator pedal. It allows the maximum acceleration with an established maximum battery power in as far as the current charge level and the temperature of the battery allows this function. In ECO mode, the heater or climate control also switches to an energy-saving program. In ECO mode, and when the high-voltage battery is fully charged, intelligent regenerative braking is deactivated.

Since the electric vehicle does not have an alternator, the high voltage on-board electrical system also supports the 12 V on-board electrical system and charges the battery as required. This ensures power for the 12 V consumers.

In addition to the familiar CAN buses (e.g. interior CAN), the electric vehicle has the electric drive CAN for communication between the various electric vehicle specific control units.

The electric vehicle consists of:

The electrical vehicle specific systems described in more detail in this function description are the electric drive and the high voltage on-board electrical system. The supply of vacuum is described are the document "Vacuum supply function".

Further electric vehicle specific systems (e.g. stationary charging and energy management) are described in separate function descriptions.

IMPORTANT CAN network

The EDCU exchanges data with other control units via the connected interior CAN which are integrated into the CAN network.

The EDCU serves as an interface (Gateway) between the CAN-bus system interior CAN and electric CAN.

Function sequence for an electric vehicle 

The further function sequence is sub-divided as follows:

Electric drive 

Further information about this can be found in the document:

High-voltage on-board electrical system 

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

Further information about this can be found in the document:

Energy management 

High-voltage on-board electrical system energy management manages the provision (supply) and consumption (balance) of electrical energy. Further information about this can be found in the document:

  Electric drive, function   GF08.00-P-0001KJE 
  High-voltage system energy management, function   GF08.00-P-2002KJE 
  Overview of system components for an electrical vehicle   GF08.00-P-9999KJE 
  High-voltage system, function   GF54.10-P-0005KJE