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REVO-E Heat pump 4 Function and functional schematics
The Heat Pump Mode is requested by the BEA body
system in order to warm up the air in the passenger cabin.
The SC620 therefore assumes internal control of the
components in the system in order to warm up the air in
the passenger cabin to the Delta T value requested by the
BEA Body.
In the heat pump mode, the refrigerant circuit to the front
box (driver's work station) is closed by a solenoid valve
controlled of the BEA-Body SW. This prevents a sudden
fogging of the front windscreen (flash fogging).
Task of the SC620:
– Control the speed of the double radial blowers / axial
fans
– Activation and speed setting of the compressor (via
frequency converter)
In Heat Pump Mode, the BEA body is not able to influence
the speed of the double radial blowers.
The value of the interior temperature to be reached is
given by the difference of the external temperature and
the ∆T required by the BEA body.
Example of ∆T – 7 Kelvin
T
passenger cabin
= [T
external
(10°C) + ∆T (7K)]
T
passenger cabin
= 17°C
This value is sent via CAN by the BEA body and is used
as an internal control signal.
The "D_ElAcMaxPowerAllowed" CAN signal (from the
vehicle's power system) specifies the maximum power
consumption of the compressor.
If the heat required cannot be implemented (e.g. malfunc-
tion), the system automatically switches to Heating/ Venti-
lation Mode.
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