Actuators

Logic of naming actuators in VW-group is simple it contains "N" + actuator number. The actuator number is unique. Here you can find fitting location, connectors and some basic information about actuators.

To our mind, actuators information is reference, so there is only simple search by number.

N

Audi R8 42 (2007- )
Audi A8 4E (2002 -)
Audi A6 4F (2005- )
Audi Q7 4L (2007- )
Audi TT 8J (2006- )
Audi A4 8K (2008-)
Audi A3 8P (2003- )
Audi Q5 8R (2009- )
N280_4L_87_____1_1105_21_Funktion

AC compressor regulating valve -N280

 

A and B - Connector of AC compressor regulating valve -N280 -N280

 

Function description:

The electric AC compressor regulating valve -N280 is pushed into the compressor and is secured by a spring ring. It forms the interface between the low, high and crankcase pressure in the compressor and is the precondition for clutchless operation.

The adjustment of the swash plate is effected by these different pressures.

That means, if a higher cooling power is required, for example, the regulating valve is activated by the Climatronic control unit -J255.

A pulse width modulated voltage signal moves the plunger in the regulating valve. The duration of the applied voltage determines the adjustment travel.

The adjustment alters the opening cross-section between the high pressure and the pressure in the crankcase of the compressor. The crankcase pressure increases and, by way of the piston stroke, effects a greater skew of the swash plate.

If an inadequate vehicle voltage is applied, faults may occur in the air conditioning system, or it may fail altogether.

If no pressure signal is detected by the high-pressure sender -G65, the regulating valve -N280 must not be activated.

If the regulating valve fails, the wash plate positions itself perpendicular to the longitudinal axis of the compressor such that the cooling function is disabled.

Display zone 1 in measured value block 001 shows the current flowing via the regulating valve -N280.

The current is calculate by the -J255. It is dependent on the specified cold output, the selected operating mode of the -J255 and the vehicle voltage.

However, for the regulating valve to regulate safely a preset minimum current must flow. For the valves currently fitted it is 0.3 A.

If the regulating valve is fully activated, a maximum current of, at present, about 0.65 A (regulated and limited by the -J255) is set depending on the vehicle voltage.

If a fault is detected in the sender -G263, the -J255 switches to emergency running and the regulating valve -N280 is only activated with a preset maximum control current specified by the software of the -J255. The maximum control current is dependent on the design version of the -J255. For the -J255 units currently fitted it may be around 0.3 A to 0.5 A (thereby reducing the cold output of the air conditioner so the cooling is no longer adequate at higher temperatures).

Display zone 2 in measured value block 001 shows the duty factor for the time during which current can actually flow.

The Climatronic control unit -J255 works at a frequency of 500 Hz (500 Hertz = 500 switch-on pulses per second). The duty cycle indicates the proportionate length of the switch-on time per pulse.

The duty cycle is selected by the -J255 such that the specified evaporator temperature at the sender -G263, which is influenced by a number of different factors, is attained. Display zone 1 in measured value block 002 shows the current applied compressor shut-off conditions.

If a compressor shut-off condition applies, the regulating valve -N280 cannot be activated (even during final control diagnosis).

If multiple compressor shut-off conditions apply simultaneously (display zone 1 in measured value block 002), the conditions are either displayed alternatingly or only the shut-off condition assigned the highest priority by the Climatronic control unit -J255 is displayed.

 

Measured value block 001

 

Display zone 1

 

Control current to activate AC compressor regulating valve -N280 in Amperes

Current flowing via AC compressor regulating valve -N280.

J Readout = "below 0.050 A"

Compressor off.

J Readout = "0.300 A to 0.800 (1.0) A"

Compressor in loop control mode, the control current is dependent on the delivered cold output.

 

Display zone 2

 

Activation of AC compressor regulating valve -N280 in %

Duty cycle of activation signal.

J Readout = "0%"

Compressor off.

J Readout = "30 ... 40% to 100%"

Compressor in loop control mode.

 

Display zone 3

 

Signal from high-pressure sender -G65 in percent. Duty cycle, dependent on pressure in refrigerant circuit.

 

Display zone 4

 

Pressure in refrigerant circuit in bar

Calculated by way of the signal from high pressure sender -G65 by the Climatronic control unit -J255.

 

Measured value block 002

 

Display zone 1

 

Current valid compressor shut-off condition

J Readout = "XX"

 

Display zone 2

 

Last compressor shut-off condition

J Readout = "XX"

 

Display zone 3

 

Last-but-one compressor shut-off condition

J Readout = "XX"

 

Display zone 4

 

Last-but-two compressor shut-off condition

J Readout = "XX"

 

Breakdown of compressor shut-off conditions

0 Compressor on (no shut-off condition detected)

1 Compressor off (pressure in refrigerant circuit was or is too high)

2 Compressor off (basic setting not performed or not performed without error)

3 Compressor off (pressure in refrigerant circuit is too low)

4 Compressor off (engine nor running or has been running for less than 2 sec.).

5 Compressor off (engine speed is below 300 rpm)

6 Compressor off (compressor switched off by ECON function)

7 Compressor off (compressor switched off by OFF function)

8 Compressor off (measured ambient temperature was below +2C and is still below +5C, there is no request for recirculated air).

9 Compressor off (no readout currently planned)

10 Compressor off (vehicle voltage is below 9.5V)

11 Compressor off (coolant temperature is too high, currently 118C)

12 Compressor off (because of a request from the engine control unit, via data bus)

13 Compressor off (because of a faulty signal from high-pressure sender -G65

14 Compressor off (because of a fault in the data bus system)

15 Compressor off (the pressure in the refrigerant circuit in this driving period was at least 30 times too high)

16 Compressor off (the measured temperature downstream of the evaporator has for over a minute been below 0C)

17 Compressor off (the measured temperature downstream of the evaporator is below -5C)

18 Compressor off (there is no valid measured value for the ambient temperature, possibly both

ambient temperature sensor -G17 and fresh air intake duct temperature sensor -G89 defective)

19 Compressor off (Climatronic control unit -J255 was switched on by "auxiliary heater" function).

20 Compressor off (readout currently vacant)

21 Compressor off (measured ambient temperature was below -8C and is still below -5C, there is no request for automatic recirculated air mode or the measured ambient temperature was below + 2C and is still below + 5C and the "recirculated air" function is not active)

22 Compressor off (the measured passenger compartment temperature is below 8C, the measured ambient temperature was below -8C and is still below -5C, there is a request

for recirculated air mode).

23 Compressor off (via the data bus system a fault message for activation of the

radiator fans was sent, e.g. by the relevant engine control unit, and received by the

Climatronic control unit -J255)

24 Compressor off (readout currently vacant)

25 Compressor off (refrigerant loss detected)

26 Compressor off (fresh air blower motor -V2 open circuit, short to earth)

27 The AC compressor was shut off due to a request from the energy management control unit -J644 over CAN (voltage deficit in vehicle electrical system).

28 Compressor off (value 1 set in adaption channel 14)

 

Measured value block 003

 

Display zone 1

 

Current valid request to reduce compressor output

J Readout = "XX"

 

Display zone 2

 

Number of requests to reduce compressor output since last erasure of fault memory

J Readout = "XX"

 




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November 30, 2012
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