Get Air conditioning and thermal management Guide for Audi RS E Tron Gt 4 Door First Generation (2021-2026)

Air conditioning and thermal management

Climate control

The Audi e-tron GT (type F8) has a 3-zone air conditioner with an air ionisation system. The occupants can use operating and display

unit for front air conditioning system E87 and operating and display unit for rear air conditioning system E265 to inform heater

and air conditioning system control unit J979 of their air conditioning requirements. The separately fitted heater and air condition-

ing system control unit J979 is the core element of the climate control in the Audi e-tron GT (type F8). Control unit J979 uses vari-

ous sensors to detect the current status in the vehicle interior and can meet the air conditioning requirements of the occupants by

activating the individual air and temperature flaps as necessary.

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Note

Further information can be found in the current flow diagram for the vehicle.

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Note

Further information on operating the air conditioner (e.g. auxiliary air conditioner) can be found in the vehicle’s Own-

er's Manual.

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Air ionisation system

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Ionisers

The task of the ioniser (emitter) is to improve the air in the vehicle interior. More precisely, it reduces pollution in the air from, for

example, dust, pollen and spores which were not filtered by the dust and pollen filter. An increased ion concentration can also help

increase occupant comfort.

To do this, ioniser control unit J897 and the two ionisers (driver side ioniser J1105 and passenger side ioniser J1106), which actual-

ly freshen the air, are required. Ionised air is available from the front centre vents.

Ionisation can be enabled and disabled in the MMI.

Reference

Further information on the air ionisation system can be found in self-study programme 665 (refer to article “Air im-

provement system”).

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Thermal management control unit J1024

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The heart of the thermal management of the Audi e-tron GT (type F8) is thermal management control unit J1024. Its main task is

to use the thermal energy present or required as efficiently as possible or to make it available. This task can be achieved by effec-

tively regulating and controlling the refrigerant and coolant circuits and using the heat pump function. The coolant circuits com-

prise the heating circuit, which is required to heat the vehicle interior, the coolant circuit for the high-voltage battery, which is used

to heat or cool the corresponding components, and the coolant circuit for the electric powertrain which regulates the temperature

of the connected components.

Thermal management control unit J1024 decides whether the coolant circuits should operate independently or in combination on

the basis of the input information and the requests from individual components. There are a large number (approx. 300) of

switches to use the coolant circuits efficiently and effectively.

The thermal management control unit J1024 is integrated in the vehicle's network via the hybrid CAN, which it uses to exchange

information with other control units and systems.

Note

Further information can be found in the current flow diagram for the vehicle.

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Electrical air conditioner compressor V470

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Electrical air conditioner compressor V470 fitted on the Audi e-tron GT works on the scroll compressor principle. This type of air

conditioner compressor has already been used on other electric Audi models.

Control unit for air conditioner compressor J842 is integrated in the electrical air conditioner compressor and communicates with

thermal management control unit J1024 via LIN bus. There is also an intermediate circuit capacitor in the air conditioner compres-

sor V470, which is discharged passively.

To improve the acoustics, electrical air conditioner compressor V470 is also equipped with a noise insulation cap.

Technical data

Voltage

Speed

Power

400 Volt DC

700 – 8500 rpm

3.9 kW

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High-voltage heater (linear) Z189

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High-voltage heater (linear) Z189 is a thermal management component. Its task is to heat the coolant in the coolant circuit as nec-

essary when requested.

A flat, electrically isolated heating element is applied to a metal plate inside high-voltage heater Z189. If current is now applied to

the heating element, it heats the metal plate. This then transmits the heat to the coolant, which is guided past on the other side of

the plate.

The nominal voltage of the high-voltage heater Z189 is 800 V. However, it is capable of providing approx. 3.5 kW of heating output

from an input voltage of approx. 250 V. The maximum heating output of approx. 10 kW is available from a voltage of 450 V.

The control unit integrated in the high-voltage heater (linear) Z189 is a LIN bus node and exchanges information with thermal

management control unit J1024 via the LIN bus.

Note

When the auxiliary air conditioning is active, the high-voltage system is active and the high-voltage components are

energised. The timer settings for charging and air conditioning are stored in the control unit for high-voltage battery

charging unit J1050.

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Refrigerant circuit

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Key:

Heating circuit

Refrigerant circuit

Coolant circuit for powertrain

Coolant circuit for high-voltage battery

The refrigerant circuit is split into two branches. The first branch is used for climate control in the vehicle interior and the task of

the second is to cool high-voltage battery 1 AX2 if necessary.

The refrigerant circuits consist of the following components:

Electrical air conditioner compressor V470, refrigerant pressure and temperature sender G395, heat condenser B, refrigerant

shut-off valve 3 N641, condenser 1, non-return valve 2, dryer 3, inner heat exchanger 4, refrigerant expansion valve 3 N638, evap-

orator 5, refrigerant pressure and temperature sender 3 G827, refrigerant pressure and temperature sender 2 G826, refrigerant

expansion valve 2 N637, heat exchanger for high-voltage battery (chiller) A and refrigerant shut-off valve 2 N640 with refrigerant

shut-off valve 5 N643.

The refrigerant shut-off valves N640, N641 and N643 are not fitted on vehicles without the heat pump function.

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Refrigerant circuit for climate control in vehicle interior

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In the refrigerant circuit for climate control in the vehicle interior, electrical air conditioner compressor V470 transports the com-

pressed gaseous refrigerant through heat condenser B and refrigerant shut-off valve 3 N641 to the condenser 1. The gaseous re-

frigerant is cooled and liquefied in the condenser. The liquid refrigerant flows through the non-return valve in the refrigerant circuit

2, the dryer 3 and the internal heat exchanger 4 to refrigerant expansion valve 3 N638. The refrigerant is atomised and vaporised

by refrigerant expansion valve 3. In this process, heat and moisture is removed from the air passing through the evaporator 5 on

the way to the vehicle interior. The gaseous refrigerant flows through the internal heat exchanger 4 back to electrical air condition-

er compressor V470.

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Refrigerant circuit for cooling high-voltage battery 1 AX2

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The refrigerant circuit for cooling high-voltage battery 1 AX2 branches off downstream of the internal heat exchanger 4 towards

refrigerant expansion valve 2 N637 and heat exchanger for high-voltage battery A. As it vaporises, the refrigerant absorbs the heat

from the coolant circuit for the high-voltage battery in the heat exchanger for high-voltage battery. From there, the refrigerant

flows on and back into the refrigerant circuit for climate control in vehicle interior before the internal heat exchanger.

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Heat pump function

With residual heat from high-voltage battery 1 AX2

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The residual heat from high-voltage battery 1 AX2 can be used to heat the vehicle interior via the heat pump function.

The gaseous refrigerant heated up in heat exchanger for high-voltage battery A is drawn in and compressed in the internal heat

exchanger 4 by the electrical air conditioner compressor V470. This heats the refrigerant further. In the heat condenser B, the hot,

gaseous refrigerant passes the heat energy to the coolant in the heating circuit. In this process, the refrigerant cools and liquefies

again. It flows through the opened refrigerant shut-off valve 2 N640, the dryer 3 and the internal heat exchanger 4 to refrigerant

expansion valve 2 N637. The refrigerant is atomised and vaporised with the help of the expansion valve N637.

The closed refrigerant shut-off valve 3 N641 and the non-return valve in the refrigerant circuit 2 prevent refrigerant from entering

the condenser 1.

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With residual heat from three-phase current drives VX89 and VX90

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The residual heat from the front and rear three-phase current drives VX89 and VX90 can also be used for the heat pump function.

The coolant heats up on the way through voltage converter for 800 V, 400 V, 48 V, 12 V A48, power contactor with boost function

J1178 and front and rear three-phase current drives VX89 and VX90. The warm coolant passes through the following valves:

changeover and mixing valve for thermal management V650, changeover and mixing valve 2 for thermal management V651 and

coolant changeover valve 2 N633; it then reaches the heat exchanger for high-voltage battery A. From there, the cooled coolant

flows through changeover and mixing valve 4 for thermal management V653 and changeover and mixing valve 7 for thermal man-

agement V656 to thermal management coolant pump 4 V620.

The heat is transferred from the coolant to the refrigerant in the heat exchanger for high-voltage battery A. The refrigerant’s route

is identical to that used for the function to heat the vehicle interior via the residual heat of high-voltage battery 1 AX2.

The residual heat from the coolant circuit for the high-voltage battery and the coolant circuit for the electric powertrain may both

be used for the heat pump function.

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Heating circuit

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The heating circuit consists of the following components:

Thermal management coolant pump 2 V618, coolant changeover valve 1 N632, high-voltage heater (linear) Z189, heat exchanger

for interior heating 6, coolant temperature sender 7 for thermal management G908, heat condenser B, coolant temperature send-

er 4 for thermal management G905.

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Example: Heating vehicle interior with high-voltage heater (linear) Z189

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Thermal management coolant pump 2 V618 transports the coolant through coolant changeover valve 1 N632 to high-voltage

heater (linear) Z189. There, the coolant is heated up as required. The heated coolant then enters the heat exchanger for interior

heating 6 and transfers the heat to the air flowing into the vehicle interior. From there, the coolant flows through the heat con-

denser B back to coolant pump V618.

Temperatures of up to approx. 65 °C can occur in the heating circuit.

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Coolant circuit for high-voltage battery

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The coolant circuit for high-voltage battery incorporates the following components:

Coolant pump for high-voltage battery V590, coolant temperature sender 1 for high-voltage battery G898, high-voltage battery 1

AX2, coolant temperature sender 2 for high-voltage battery G899, changeover and mixing valve 4 for thermal management V653,

charging unit 1 for high-voltage battery AX4, restrictor 10, changeover and mixing valve 7 for thermal management V656, coolant

temperature sender 8 for thermal management G968, heat exchanger for high-voltage battery (chiller) A, coolant temperature

sender 1 for thermal management G902 and a non-return valve 9.

Temperatures of approx. 30 °C may occur during operation.

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Example: Circulating coolant around high-voltage battery 1 AX2

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Coolant pump for high-voltage battery V590 transports the coolant through high-voltage battery 1 AX2 to changeover and mixing

valve 4 for thermal management V653. The coolant returns to coolant pump for high-voltage battery V590 from changeover and

mixing valve 4 for thermal management. The refrigerant circuit for cooling high-voltage battery 1 AX2 is not active as part of this.

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Example: Actively cooling high-voltage battery 1 AX2

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Coolant pump for high-voltage battery V590 transports the coolant through high-voltage battery 1 AX2, changeover and mixing

valve 4 for thermal management V653, changeover and mixing valve 7 for thermal management V656, the heat exchanger for

high-voltage battery A and changeover and mixing valve 4 for thermal management V653.

The activated refrigerant circuit for cooling high-voltage battery 1 AX2 branches off after the internal heat exchanger 4 towards

refrigerant expansion valve 2 N637 and heat exchanger for high-voltage battery A. As it vaporises, the refrigerant absorbs the heat

from the coolant circuit for the high-voltage battery in the heat exchanger for high-voltage battery. From there, the refrigerant

flows on and back into the refrigerant circuit for climate control in the vehicle interior before the internal heat exchanger where it

can release its heat energy into the atmosphere in the condenser 1.

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Example: Heating high-voltage battery 1 AX2

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Coolant pump for high-voltage battery V590 transports the coolant through high-voltage battery 1 AX2, changeover and mixing

valve 4 for thermal management V653, changeover and mixing valve 7 for thermal management V656, the heat exchanger for

high-voltage battery A and changeover and mixing valve 4 for thermal management V653 before returning to coolant pump V590.

A regulated portion of the coolant flow can be transported into the heating circuit downstream of changeover and mixing valve 4

for thermal management V653 and the non-return valve 9. It flows into high-voltage heater (linear) Z189 and is heated there. The

coolant then passes through the heat exchanger for interior heating 6 and the heat condenser B. Thermal management coolant

pump 2 V618 pumps the coolant through coolant changeover valve 1 N632 into the coolant circuit for electric powertrain. The

heated coolant flows back into the coolant circuit for the high-voltage battery via coolant changeover valve 2 N633.

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Coolant circuit for electric powertrain

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The following components are incorporated in the coolant circuit for the electric powertrain:

Thermal management coolant pump 4 V620, voltage converter for 800 V, 400 V, 48 V, 12 V A48, power contactor with boost func-

tion J1178, coolant temperature sender 5 for thermal management G906, three-phase current drives VX89 and VX90, changeover

and mixing valve for thermal management V650, coolant temperature sender 2 for thermal management G903, changeover and

mixing valve 2 for thermal management V651, coolant temperature sender 3 for thermal management G904, low-temperature

radiator 8, coolant temperature sender 9 for thermal management G1017, coolant changeover valve 2 N633. The restrictor 10,

non-return valve 9, coolant expansion tank 2 (for high-voltage system) 7 and coolant shortage indicator sender 2 G837 are also

part of the coolant circuit for the electric powertrain.

Temperatures of up to 65 °C can occur in the coolant circuit for the electric powertrain.

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Example: Cooling electric powertrain

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Thermal management coolant pump 4 V620 pumps coolant through voltage converter for 800 V, 400 V, 48 V, 12 V A48 and power

contactor with boost function J1178, the three-phase current drives VX89 and VX90, changeover and mixing valve for thermal

management V650 to changeover and mixing valve 2 for thermal management V651. The position of coolant changeover valve 2

N633 regulates the amount of coolant which flows through the low-temperature radiator 8. The coolant flows back to thermal

management coolant pump 4 V620 from coolant changeover valve 2 N633.

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Cooling high-voltage battery 1 AX2 when charging

Example: Charging high-voltage battery with alternating current (AC) while cooling is active

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Coolant pump for high-voltage battery V590 transports the coolant through high-voltage battery 1 AX2, changeover and mixing

valve 4 for thermal management V653, charging unit 1 for high-voltage battery AX4 and the restrictor 10 to changeover and mix-

ing valve 7 for thermal management V656. From there, the coolant enters the coolant circuit for the electric powertrain. Thermal

management coolant pump 4 V620 also pumps the coolant on through voltage converter for 800 V, 400 V, 48 V, 12 V A48 and

power contactor with boost function J1178 directly to changeover and mixing valve for thermal management V650. The coolant

continues through changeover and mixing valve 2 for thermal management V651 and enters coolant changeover valve 2 N633.

From there, the coolant is transported to heat exchanger for high-voltage battery A, changeover and mixing valve 4 for thermal

management V653 and coolant pump for high-voltage battery V590.

The activated refrigerant circuit for cooling the high-voltage battery absorbs the heat from the coolant circuit for high-voltage bat-

tery in heat exchanger for high-voltage battery A while the refrigerant is vaporising and transfers the heat to the condenser 1.

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Example: Charging high-voltage battery with direct current (DC) while cooling is active

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In the high-voltage battery cooling circuit, the coolant flows through high-voltage battery 1 AX2, changeover and mixing valve 4

for thermal management V653 directly to changeover and mixing valve 7 for thermal management V656. From there, it travels

through the heat exchanger for high-voltage battery A, changeover and mixing valve 4 for thermal management V653 and to cool-

ant pump for high-voltage battery V590. In the heat exchanger for high-voltage battery, the thermal energy from the coolant is

transferred to the refrigerant in the refrigerant circuit for cooling high-voltage battery 1 AX2. The thermal energy is released into

the atmosphere with the help of the condenser 1.

During DC charging, the coolant circuit for the electric powertrain is also active.

Thermal management coolant pump 4 V620 pumps coolant through voltage converter for 800 V, 400 V, 48 V, 12 V A48 and power

contactor with boost function J1178, directly to changeover and mixing valve for thermal management V650 and then to mixing

valve 2 for thermal management V651. The position of coolant changeover valve 2 N633 regulates the amount of coolant which

flows through the low-temperature radiator 8. The coolant flows back to thermal management coolant pump 4 V620 from coolant

changeover valve 2 N633.

A regulated portion of the warm coolant can branch off downstream of changeover and mixing valve for thermal manage-

ment V650 into the heating circuit and become mixed with the coolant there. Thermal management coolant pump 2 V618 trans-

ports the coolant through coolant changeover valve 1 N632 back into the coolant circuit for the electric powertrain.

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Air conditioning and thermal management for Your Audi RS E Tron Gt 4 Door First Generation (2021-2026)

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