Compressor

Compressor

An infinitely variable 7-cylinder (adjustable) swash plate compressor is used for the air conditioning. The working volume stands at 160 cm3 at 100 % output.
Refrigeration oil capacity = 195 ± 15 cm3 ND8







Functions
The compressor output varies between 5 % and 100 %. The working volume and the output are changed by altering the setting of the swash plate (the set angle alters in relation to the drive axle). The higher the required cooling power, the greater the intake pressure.
The piston stroke is controlled by means of the high pressure/low pressure ratio. The control valve in the compressor is diaphragm-controlled via the intake pressure and connects the high-pressure side with the crankcase. The crankcase pressure is determined by means of the high and low pressure prevailing at the control valve and an internal throttle bore. The pitch of the swash plate is thus dependent on the crankcase pressure and thus on the pressure conditions at the top side and the underside of the piston. The delivery rate is thus influenced by the control valve. This pressure control process ensures that the compressor normally remains operative at all times.

Air conditioning compressor control system
The DME system activates the compressor via a relay at the earliest approx. 8 seconds after starting the engine. This relay is located in relay carrier 2.

The following conditions result in "Shut-down of the a/c compressor":
- Temperature conditions
- At outside temperatures of <3 °C or <37.4 °F (see also section on "Temperature sensor for fresh air intake") the compressor is shut down. The control unit only allows the compressor to be switched on again at 3.5 °C or 38.3 °F.
- The compressor is shut down at coolant temperatures of >118 °C or >244 °F and re-started at <115 °C or <239 °F.

- Pressure conditions
- The compressor is switched off at coolant pressures of less than 2 bar (low pressure) and >28 bar (high pressure).

- Kickdown conditions (acceleration)
- At a pedal travel of > 92 % (shortly before pedal stop), the compressor is - when the pedal travel deviation is less than 6 seconds - switched off for 6 seconds or for a maximum of 9 seconds (duration of pedal travel deviation > 6 seconds). Classic full-load cut-off is not incorporated.

Condenser
The condensers of the air conditioning system are installed together with the radiators in space-saving configuration on the left and right sides at the front end of the vehicle (see also section "Refrigeration circuit").

Coolant tank/filter drier
The coolant tank is installed in the fresh air chamber at front left, next to the battery. The pressure relief valve (see arrow) for the cooling system is also located here.







Expansion valve and additional components