Valeo REVO-E Workshop Manual Download

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REVO-E Heat pump

4 Function and functional schematics

Function and functional
schematics of the REVO-E Heat pump

4.1

General function

The fully electric rooftop air-conditioning system (in the
following referred to as ADA) REVO-E for hybrid, electric
and trolley buses is a proven system, especially with its
intelligent energy management, meaning cooling is
provided as needed depending on existing power, and
with the special way its compressor has been installed.
The electric compressor is located on the roof in an
exceptionally compact manner, and not on the rear of the
vehicle as in previous versions. This has, in the purest
sense of the word, obvious advantages and makes the
system closed by integrating all of the components
carrying refrigerant, an efficient, tight and almost mainte-
nance free design (solo design without front box connec-
tion).

The REVO-E as heat pump

The REVO-E air-conditioning system is the basis for the
REVO-E heat pump.
The refrigeration cycle of the REVO-E air-conditioning
system has been modified in such a way that it can also
represent the functionality of a heat pump in addition to
the air-conditioning operation. The basic principle is
based on the reversal of the refrigeration cycle.
Regulation and control in the air-conditioning mode corre-
spond to the REVO-E air-conditioning system. Details can
be found in the Workshop Manual REVO-E.
Explanations in the following chapters refer largely to the
new functions of the heat pump.

The intelligent controller logic of the SC620 controls
further the entire system. It communicates with the vehicle
via CAN bus.

The climate control works identical as in the REVO-E

air-conditioning system (see Workshop Manual REVO-E).

The two variants of the REVO-E HP are listed in the

Table

201

Both systems differ only slightly. With the additional func-
tion "hot gas de-icing", the REVO-E HP + is able to heat
the passenger compartment in heat pump mode at signif-
icantly lower temperatures (

≥

-5 ° C). This is realized with

adapted software and additional components in the refrig-
eration cycle.

Functionality of the REVO-E Heat pump in the vehicle
line of the Volvo 7900 Electric

The HVAC control system of the vehicle is responsible for
regulating the Heating, Ventilation and Cooling modes in
the Volvo E Bus. The REVO-E system is operated only as
a “slave” system and only follows the vehicles require-
ments.

If the ADA is activated by switching on the vehicles elec-
trical network. all of the system’s sensor values are auto-
matically verified for plausibility and the system will be set
to “Standby Mode”. Various sensor values are used as the
basis for calculating the bus-side requirements, including
those from the passenger cabin sensors of the ADA.

These requirements are sent via CAN bus over the Dbus
to the SC620 as needed.
The SC620 implements these requirements (mode /
blower speed, etc.).

The REVO-E will turn off if there are any limitations in the
temperature / high-voltage supply, etc.