Cooling system overview
Cooling systems
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Introduction of smart fortwo electric drive (3rd Generation) • Model Series 451
The smart fortwo electric drive has 2 cooling
systems. Climate control of the interior compart-
ment is performed by a refrigerant circuit and
cooling of the drivetrain components is
performed by a coolant circuit. On vehicles with
code (V03) Battery cooling system, the coolant for
the high-voltage battery can additionally be
cooled by the air conditioning system via a refrig-
erant/coolant heat exchanger (chiller).
Interior cooling system
As on vehicles with a combustion engine, the inte-
rior is cooled via the refrigerant circuit with the
following components:
• Electric refrigerant compressor
• Condenser
• Expansion valve
• Evaporator
On vehicles with code (V03) Battery cooling
system, the expansion valve can also be shut off
electrically. There is an additional electrical
expansion valve (battery) on the chiller.
Drivetrain component cooling system
Cooling of the drivetrain components is
performed by a coolant circuit. The following
components are cooled:
• Electric drive motor
• Power electronics control unit
• High-voltage battery
• On-board charger
The cooling module, consisting of a cooler,
coolant expansion reservoir and condenser, is
the same as that of the smart with combustion
engine.
The drivetrain control unit records the values
from the temperature sensors in the components
involved and controls the coolant fan motor and
electrical coolant pump according to require-
ments.
The coolant (glycol/water mixture) is pumped
from the cooler to the drivetrain components by
the electric coolant pump. From there, it returns
to the coolant expansion reservoir.
The coolant fan motor can be operated in two
stages. It is switched via the fan stage switching
relay and fan control series resistor by the driv-
etrain control unit.
