Audi Q7: Electrically-Driven A/C Compressor
WARNING
Risk of short circuit
The A/C compressor works with up to 288 volts at 800
to 8,600 RPM.
Do not touch the A/C compressor when the ignition is
turned on or when the drive machines are activated
because of the short circuit risk.
- The A/C compressor extracts the refrigerant gas from the
evaporator, compresses it and relays it to the condenser.
- The electric motor for the A/C compressor is powered with
voltage from the Electric Drive Power and Control Electronics
-JX1-.
- The A/C Compressor Control Module -J842- integrated in the
A/C compressor controls the rotation and thereby the output for
the A/C compressor (Electrical A/C Compressor -V470-)
corresponding with the Data bus receiving requirements. Use the
Vehicle Diagnostic Tester in the "Guided Fault Finding" Function
for the A/C System and the Battery Regulation.
- There is no A/C Compressor Regulator Valve -N280- installed
in the electrically-driven A/C compressor.
- Check the attachment points on the A/C compressor and the
bracket prior to installation. The contact surfaces must be
clean and free of rust and grease. Otherwise, repair the contact
surfaces with the Contact Surface Cleaning Set -VAS6410-. Refer
to
→ Electrical Equipment General Information; Rep. Gr.97; Wire and
Connector Repair.
Note
- Check the amount of refrigerant oil in the new A/C
compressor if the A/C Compressor Control Module -J842- is
faulty. Do not flush the refrigerant circuit with R134a.
- The A/C Compressor Control Module -J842- and the Electrical
A/C Compressor -V470- are one component and are currently not
able to be separated.
- There is no A/C Compressor Regulator Valve -N280- installed
in the electrically driven A/C compressor. The A/C compressor
output is regulated externally by the A/C compressor speed.
Refer to
→ Wiring diagrams, Troubleshooting & Component locations
and use the Vehicle Diagnostic Tester in the "Guided Fault
Finding" Function for the A/C System and the Battery Regulation.
- The electrically-driven A/C compressor functions according
to the principle of a spiral charger (similar to a G-charger).
- The A/C compressor contains refrigerant oil, which can be
mixed with refrigerant R134a under any temperature.
- The data plate lists the type of refrigerant required for
the A/C compressor.
- The installed electronics are controlled by the speed of the
A/C compressor power output (and the pressure on the low
pressure side) within the specified range (control
characteristic).
- The engine should only be started if the refrigerant circuit
is completely assembled.
- The A/C compressor is equipped with a protected oil supply,
this prevents A/C compressor damage in the event that the system
is empty. This means that approximately 40 to 50 cm3
of refrigerant oil remains in the A/C compressor.
- The electrically-driven A/C compressor has a relief valve
like the mechanically-driven A/C compressor.
- Hybrid drive on vehicles with battery cooling is only
possible with a fully charged A/C system in which there are no
stored errors. Use the Vehicle Diagnostic Tester in the "Guided
Fault Finding" Function for the A/C System and the Battery
Regulation.
- After the installation of the electrically-driven A/C
compressor and the subsequent filling of the refrigerant
circuit, start the A/C compressor for the first time using the
"compressor intake" function for the basic setting. The A/C
compressor may otherwise become damaged if before installation,
refrigerant oil was improperly stored in the A/C compressor
compression chamber. Use the Vehicle Diagnostic Tester in the
"Guided Fault Finding" Function for the A/C System and the
Battery Regulation.
- Only activate the electrically-driven A/C compressor when
the refrigerant circuit is filled. The A/C compressor may become
damaged if the A/C compressor is run when the refrigerant
circuit is empty. Use the Vehicle Diagnostic Tester in the
"Guided Fault Finding" Function for the A/C System and the
Battery Regulation.
Condenser
The condenser conducts heat from compressed refrigerant gas
to the ambient air.
This condenses the refrigerant gas to fluid.
Note
- Depending on the version of the refrigerant circuit, the
receiver/dryer is installed (integrated) either on the condenser
or inside the condenser. Refer to
→ Heating, Ventilation and Air Conditioning; Rep. Gr.87; System
Overview - Refrigerant Circuit (vehicle-specific
repair manual) and the Parts Catalog.
- The condenser is available in different versions and can be
differentiated only by the part number on the outside. For
version -1-, the condenser is
divided into two areas "2 way condenser". For version
-2-, the condenser is divided into
four areas "4 way condenser".
- This illustration shows a condenser with the receiver/dryer
-C- installed.
- The gaseous refrigerant enters at the connection
-A- into the condenser. The
refrigerant is then cooled inside the condenser and becomes
fluid.
- The liquid refrigerant collects in the receiver/dryer
-C- (with dryer) and flows through
the lower cooling area towards the connection
-B-.
- Depending on the design of the condenser (interior volumes,
delivery flow, etc.), the amount of the refrigerant that is
needed to fill the refrigerant circuit may vary. Therefore
always be sure of the correct version and allocation for the
condenser. Refer to
→ Chapter "Refrigerant R134a Capacities" and the
Parts Catalog.
Evaporator
The evaporator is available in different versions. Depending
on the version and the function, the necessary heat energy of
the air flow (for example, an evaporator in the A/C unit or in
the battery cooling module) or flowing coolant (for example near
the high voltage battery heat exchanger) is extracted for
refrigerant evaporation. Refer to
→ Heating, Ventilation and Air Conditioning; Rep. Gr.87; System
Overview - Refrigerant Circuit (vehicle-specific
repair manual).
Note
Two versions of evaporator are described.
Evaporator in A/C Unit (or in Battery Cooling Module)
The fluid refrigerant evaporates in the evaporator pipe
coils. The heat required for this is extracted from the air
flowing on the evaporator ribbing. The air cools off.
Refrigerant evaporates and is extracted with the absorbed heat
by the A/C compressor.
A defined amount of refrigerant is supplied to the
evaporator by a restrictor or expansion valve. In systems with
expansion valve, the throughput is regulated so that only
gaseous refrigerant escapes the evaporator outlet.
Evaporator/High Voltage Battery Heat Exchanger (Chiller)
The liquid refrigerant evaporates in evaporator (heat
exchanger). The heat required for this is extracted from the
flowing refrigerant. The coolant cools, the refrigerant
evaporates and is extracted with the absorbed heat by the A/C
compressor.
A defined amount of refrigerant is supplied to the
evaporator by a restrictor (or expansion valve) and a shut off
valve. The throughput of the refrigerant (for example the
coolant) is regulated so that only gaseous refrigerant escapes
the evaporator outlet. Refer to
→ Heating, Ventilation and Air Conditioning; Rep. Gr.87; System
Overview - Refrigerant Circuit (vehicle-specific
repair manual).
Heat Pump Operation Heater Core
The gaseous or vaporous refrigerant that is compressed by
the A/C compressor is liquefied in the A/C compressor
-A- and at the same time released
heat is transferred to the coolant flowing by. Refer to
→ Heating, Ventilation and Air Conditioning; Rep.
Gr.87; Refrigerant Circuit; System Overview - Refrigerant
Circuit.
Fluid Collector
In some operating conditions (for example heat pump
operation) the receiver/dryer (for example on the condenser) is
not incorporated in the refrigerant circuit. The fluid collector
-B- collects the refrigerant, and
saves it if a specific quantity of refrigerant is not needed and
directs it in an uninterrupted stream to the expansion valve (in
front of the evaporator in the heater and A/C unit) or to the
heat exchanger in the refrigerant circuit of the high-voltage
system. Refer to
→ Heating, Ventilation and Air Conditioning; Rep.
Gr.87; Refrigerant Circuit; System Overview - Refrigerant
Circuit.
Reservoir
The reservoir collects the vaporized and gaseous mixture
coming from the evaporator to ensure the compressor only
receives gaseous refrigerant. Gaseous refrigerant is formed from
the vapor.
The refrigerant oil flowing in the circuit is not retained
in the reservoir as it has an oil drilling.
Moisture which has entered the refrigerant circuit during
repairs will be collected by a filter (desiccant bag) in the
reservoir.
Gaseous refrigerant is extracted with oil by the A/C
compressor.
Note
- Replace the reservoir if refrigerant circuit has been open
for a long time (beyond the normal repair time) and moisture has
penetrated inside, or if required due to a specific complaint.
Refer to
→ Chapter "Refrigerant Circuit Components, Replacing".
- Remove the sealing plugs -A-
and -B- only immediately before
installing.
- A desiccant bag in an unsealed reservoir is saturated with
moisture after a short period of time and unusable.
- When installing, note arrow for direction of flow if
necessary.
Restrictor
Restrictor in Front of the Evaporator
The restrictor creates a constriction. This restriction
reduces the flow and creates high and low pressure sides in the
refrigerant circuit. Before the restrictor the refrigerant which
is under a higher pressure is warm. After the restrictor the
refrigerant which is under a low pressure is cold. Before the
restriction there is a strainer for contaminants and after the
restriction there is a strainer, to atomize the refrigerant
before it reaches the evaporator.
Note
- Arrow -A- on restrictor points
to the evaporator.
- Replace after each opening of the circuit.
- There are different versions, therefore pay attention to the
different customer service information sources. Refer to
→ Heating, Ventilation and Air Conditioning; Rep. Gr.87; System
Overview - Refrigerant Circuit and (vehicle-specific
repair manual) and to the Parts Catalog .
Restrictor in Front of the High Voltage Battery Heat
Exchanger (Chiller)
The restrictor creates a constriction. This restriction
reduces the flow and creates high and low pressure sides in the
refrigerant circuit. Before the restrictor the refrigerant which
is under a higher pressure is warm. After the restrictor the
refrigerant which is under a low pressure is cold.
Note
- The illustration shows a refrigerant line
-A- with a fixed installed
restrictor -B- (without a strainer)
- The diameter of the illustrated variable orifice
-B- is approximately 0.7 mm.
Depending on the version of the refrigerant line this
constriction is either installed fixed in the refrigerant line
or only inserted. For the inserted version a strainer for
flowing deposits may be installed, which can be blocked by the
variable orifice.
- Before installing check for debris and if necessary clean or
replace.
- There are different versions, therefore pay attention to the
different customer service information sources. Refer to
→ Heating, Ventilation and Air Conditioning; Rep. Gr.87; System
Overview - Refrigerant Circuit and (vehicle-specific
repair manual) and to the Parts Catalog.
Receiver/Dryer
The receiver/dryer collects the fluid drops and then directs
them in an uninterrupted stream to the expansion valve. Moisture
which has entered the refrigerant circuit during repairs will be
collected by the desiccant bag in the receiver/dryer.
Note
- Replace the receiver/dryer if refrigerant circuit has been
open for a long time (beyond the normal repair time) and
moisture has penetrated inside, or if required due to a specific
complaint. Refer to
→ Chapter "Refrigerant Circuit Components, Replacing".
- Only remove sealing plugs shortly before installation.
- A desiccant bag in an unsealed receiver/dryer becomes
saturated with moisture after a short period of time and
unusable.
- When installing, note arrow for direction of flow if
necessary.
- Depending on the version of the refrigerant circuit, the
receiver/dryer is also installed (integrated) either on the
condenser or inside the condenser. Refer to
→ Heating, Ventilation and Air Conditioning; Rep. Gr.87; System
Overview - Refrigerant Circuit (vehicle-specific
repair manual) and the Parts Catalog.
- The procedure is different for each complaint depending on
the version of the receiver/dryer and the dryer cartridge. If
the receiver/dryer, for example, is attached to the condenser,
then it can be replaced complete with the drying cartridge. If
the receiver/dryer, for example, is inside the condenser, then
the dryer cartridge, and any possible additional filters, can be
replaced separately, on most versions. If the receiver/dryer is
inside the condenser and there is absolutely no way to replace
the reservoir or the dry cartridge individually, then the entire
condenser must be replaced. Refer to
→Heating, Ventilation and Air Conditioning; Rep. Gr.87
and
→Heating, Ventilation and Air Conditioning; Rep. Gr.87
(vehicle-specific repair manual) and Parts Catalog.
- Depending on the construction of the refrigerant circuit,
the receiver can also be secured onto the condenser. Refer to
→ Heating, Ventilation and Air Conditioning; Rep. Gr.87; System
Overview - Refrigerant Circuit (vehicle-specific
repair manual) and the Parts Catalog.
Expansion Valve
The expansion valve atomizes the streaming refrigerant and
controls the flow quantity so that the vapor is gaseous only at
the evaporator outlet, depending on the heat transmission.
Note
- Be sure to use the correct part number when replacing the
expansion valve. Refer to the Parts Catalog.
- Different characteristic curves matched to the appropriate
circuit. Refer to
→ Heating, Ventilation and Air Conditioning; Rep. Gr.87; System
Overview - Refrigerant Circuit (vehicle-specific
repair manual) and the Parts Catalog.
- Depending on the A/C compressor version, there may be a
valve installed on the high pressure side of the A/C compressor,
which prevents the liquid refrigerant from flowing back into the
compressor once the A/C is turned off. If an A/C compressor with
this valve is installed in a vehicle with a refrigerant circuit
having an expansion valve, then it may take some time until the
pressure in the high pressure side decreases (the expansion is
cold and the pressure in the low pressure side quickly increases
after it is turned off, the expansion valve closes and the
refrigerant flows slowly into the low pressure side). If the A/C
compressor is switched on, the pressure on the low pressure side
goes down, the expansion valve open and the refrigerant can flow
of the low pressure side.
Expansion Valve with Shut-Off Valve
Note
There are different versions of the shut-off valve with
different functions and with different names. The following
illustrated Hybrid Battery Refrigerant Shut-Off Valve 2 -N517-
is for example installed on an Audi Q7 hybrid in the battery
cooling module. Refer to
→ Heating, Ventilation and Air Conditioning; Rep.
Gr.87; Refrigerant Circuit; System Overview - Refrigerant
Circuit.
- The expansion valve -A- with
the Hybrid Battery Refrigerant Shut-Off Valve 2 -N517--B-
atomizes the streaming refrigerant and regulates the refrigerant
flow rate to the evaporator in the battery cooling module for
the Hybrid Battery Unit -AX1- so that the vapor becomes gaseous
only at the evaporator output, depending on the heat
transmission.
- If the Hybrid Battery Refrigerant Shut-Off Valve 2 -N517--B-
is activated by the electronics and is open, it lets refrigerant
flow through the expansion valve -A-
to the evaporator in the battery cooling module.
- The expansion valve -A- with
the Hybrid Battery Refrigerant Shut-Off Valve 2 -N517--B-
is installed on vehicles with a battery cooling module. It is
activated when the A/C system is in operation, if it is
necessary to cool the Hybrid Battery Unit -AX1-.
- If the Hybrid Battery Refrigerant Shut-Off Valve 2 -N517--B-
is activated by the electronics (for example, by the Battery
Regulation Control Module -J840-), it is open and lets the
refrigerant flow according to its control characteristic toward
the evaporator in the battery cooling module.
- The Hybrid Battery Refrigerant Shut-Off Valve 2 -N517--B-
attached to the expansion valve -A-
is activated, for example, by the Battery Regulation Control
Module -J840-. Refer to
→ Wiring diagrams, Troubleshooting & Component locations.
Use the Vehicle Diagnostic Tester in the "Guided Fault Finding"
Function for the A/C System and the Battery Regulation.
- If, for a vehicle with two evaporators (one in the A/C unit
and one in the battery cooling module, for example on the Q5
Hybrid), the measured temperature on one of the evaporators
corresponds to the specified value or the specified value falls
short, but does not reach the required specified value on the
other evaporator, the following adjustment is performed: the
Battery Regulation Control Module -J840- activates the electric
A/C compressor with increased speed (thereby increasing the A/C
system cooling output and decreasing the pressure on the low
pressure side as well as the evaporator temperature) via the
Electric Drive Power and Control Electronics -JX1- and the A/C
Compressor Control Module -J842-. If the specified value for the
temperature falls short at one of the evaporators, the Battery
Regulation Control Module -J840- activates the Hybrid Battery
Refrigerant Shut-Off Valve 1 -N516- or the Hybrid Battery
Refrigerant Shut-Off Valve 2 -N517-, so that the evaporator
which is too cold is no longer supplied with refrigerant. Use
the Vehicle Diagnostic Tester in the "Guided Fault Finding"
Function for the A/C System.
Refrigerant Cut-Off Valve
Note
- There are different versions of the shut-off valve with
different functions and with different names. The following
illustrated Hybrid Battery Refrigerant Shut-Off Valve 1 -N516-
is for example installed on an Audi Q7 hybrid. Refer to
→ Heating, Ventilation and Air Conditioning; Rep.
Gr.87; Refrigerant Circuit; System Overview - Refrigerant
Circuit.
- There are various designations, depending on the function
and the vehicle. Refer to
→ Heating, Ventilation and Air Conditioning; Rep.
Gr.87; Refrigerant Circuit; System Overview - Refrigerant
Circuit.
Shut-Off Valve with Two Switching States (Open Or Closed)
- Hybrid Battery Refrigerant Shut-Off Valve 1 -N516- (for
example the Audi Q5 Hybrid)
- Heater and A/C Unit Refrigerant Shut-Off Valve -N541- (for
example on Audi A3 e-tron)
- High-Voltage Battery Heater Core Refrigerant Shut-Off Valve
-N542- (for example on Audi A3 e-tron)
- Refrigerant Shut-Off Valve -V424- (for example on Audi Q7
e-tron)
- If the shut-off -A- is not
activated by the electronics, it is open and lets the
refrigerant flow through to the evaporator in the A/C unit.
- The shut-off valve -A- is
installed on vehicles with the battery cooling module. It is
activated in hybrid mode when no A/C system operation is desired
for the passenger compartment or for the Hybrid Battery Unit
-AX1-, but is necessary for battery cooling.
- Observe the arrow -B- attached
to the shut-off valve -A-, which
shows the flow direction of the refrigerant (from the condenser
to the evaporator in the A/C unit)
- The solenoid coil -C- attached
to the shut-off valve is activated for example from the Battery
Regulation Control Module -J840-
→ Wiring diagrams, Troubleshooting & Component locations.
Use the Vehicle Diagnostic Tester in the "Guided Fault Finding"
Function for the A/C System and the Battery Regulation.
- On a vehicle with two evaporators (one in the A/C unit and
one for example on the Audi Q5 Hybrid) in the battery cooling
module, if the measured temperature on one of the evaporators
corresponds to the target value or the target value falls short,
but does not reach the required target value on the other
evaporator, the following adjustment is performed: the relevant
control module (for example the Battery Regulation Control
Module -J840- n the Audi Q5 hybrid) activates the electric A/C
compressor with increased speed (thereby increasing the A/C
cooling output and decreasing the pressure on the low pressure
side as well as the evaporator temperature) via the A/C
Compressor Control Module -J842-. If the target value falls
short for the temperature of one of the evaporators, the
relevant control module (for example the Battery Regulation
Control Module -J840- on the Audi Q5 Hybrid the Hybrid Battery
Refrigerant Shut-Off Valve 1 -N516- or the Hybrid Battery
Refrigerant Shut-Off Valve 2 -N517-) activates so that the
evaporator which is too cold is no longer supplied with
refrigerant. Use the Vehicle Diagnostic Tester in the "Guided
Fault Finding" Function for the A/C System and
→ Heating, Ventilation and Air Conditioning; Rep. Gr.87; System
Overview - Refrigerant Circuit (for the specific
vehicle).
Shut-Off Valve, which is Regulated via the Characteristic
Curve
- Refrigerant Shut-Off Valve 2 -N640- through Refrigerant
Shut-Off Valve 5 -N643- (for example on Audi Q7 e-tron)
- Refrigerant Expansion Valve 1 -N636- (for example on Audi Q7
e-tron)
- The shut-off valve -A- is
activated via a step motor -B- from
the respective control module via the characteristic curve
(opened or closed).
- If the shut-off valve works as a regulator valve (for
example on the Audi Q7 as Refrigerant Expansion Valve 1 -N636-)
it is only open until the temperature for the heat exchanger is
reached. Refer to
→ Heating, Ventilation and Air Conditioning; Rep.
Gr.87; Refrigerant Circuit; System Overview - Refrigerant
Circuit.
- Shut-off valves activated via the step motor do not have a
specified resting position. For this reason before performing
procedures on the refrigerant circuit it must be set to a
specified position (open or closed). Refer to
→ Heating, Ventilation and Air Conditioning; Rep.
Gr.87; Refrigerant Circuit; System Overview - Refrigerant
Circuit.
- Depending on the design of the refrigerant circuit multiple
shut-off valves can be combined in one valve block (for example
on the Audi Q7 e-tron). Refer to
→ Heating, Ventilation and Air Conditioning; Rep.
Gr.87; Refrigerant Circuit; System Overview - Refrigerant
Circuit.
- The step motor is adapted and activated via the data wires
(LIN Bus) from the respective control module according to its
component location. Refer to
→ Heating, Ventilation and Air Conditioning; Rep.
Gr.87; Refrigerant Circuit; System Overview - Refrigerant
Circuit. Use the Vehicle Diagnostic Tester in the
"Guided Fault Finding" function.
READ NEXT:
In this refrigerant pipe, the flowing fluid warm refrigerant
on the high pressure side is delivered into the low pressure
side as flowing, vapor, cold refrigerant to increase the
efficiency of the
Refrigerant Circuit with Expansion Valve and Evaporator
The following illustration shows only the principle of a
refrigerant circuit, the design of the refrigerant circuit in
the respective vehicle
General Information
Only valves and connections that are resistant to
refrigerant R134a and refrigerant oil must be installed.
Different connections (outer diameter) for high pressure and
low pre
SEE MORE:
Overview - Front Center Armrest
1 - Center Console
2 - Front Center Armrest
Removing and installing. Refer to
→ Chapter "Front Center Armrest, Removing and Installing".
3 - Cover
Replace damaged or deformed clips
Removing and installing. Refer to
→&nbs
Overview - Rear Seat Entertainment System
The Rear Seat Entertainment System (RSE) consists of:
Left Rear Information Display Control Head Control Module
-J648-/Right Rear Information Display Control Head Control
Module -J649- on the left/right front seat backrest frame
Information Electronics