Contents Wiring diagrams Section: Automatic HVAC System All sections

Climate Control -- Basic Knowledge -- 203 Chassis: Overview Mercedes-Benz C-class W204/S204

Automatic HVAC System 2 illustrations ~556 words

Convenience automatic air conditioning (C-AAC) functional description table of contents - GF83.40-P-0996P

MODELS 203.0 /2 /7 up to 31.5.01 with CODE (581) Automatic air conditioning

MODELS 203.0 /2 /7 as of 1.6.01 with CODE (581) Comfort automatic air conditioning

Convenience automatic air conditioning (C-AAC), functionGF83.40-P-0004P
Convenience automatic air conditioning (CAAC) networking of componentsGF83.40-P-0004-01P
Ventilation system functionGF83.10-P-2000P
Heater circuit functionGF83.20-P-2003P
Refrigerant circuit functionGF83.40-P-2001P
Regulation of comfort automatic air conditioning, functionGF83.40-P-2006P
Temperature control functionGF83.57-P-2000P
Residual engine heat utilization functionGF83.75-P-2000P
Convenience automatic air conditioning (C-AAC) system component overview, location/ task/design/functionGF83.40-P-9996P

Table of contents, automatic air conditioning (AAC) function description - GF83.40-P-0999P

MODEL 203.0 /2 /7 up to 31.5.01 with CODE (580) Air conditioning (or Tempmatic for USA)

MODEL 203.0 /2 /7 as of 1.6.01 with CODE (580) Automatic air conditioning

MODEL 203.0 /2 /7 as of 24.4.04 except CODE (581) Comfort automatic air conditioning

Automatic air conditioning (AAC), functionGF83.40-P-0001P
Automatic air conditioning (AAC) component networkingGF83.40-P-0001-02P
Ventilation system functionGF83.10-P-2000P
Heater circuit functionGF83.20-P-2003P
Refrigerant circuit functionGF83.40-P-2001P
Regulation of automatic air conditioning, functionGF83.40-P-2004P
Temperature control functionGF83.57-P-2000PC
Residual engine heat utilization functionOn vehicles with code (450) Taxi version or code (670) Residual engine heat utilization system (REST)GF83.75-P-2000P
Automatic air conditioning system component summary, location/task/design/functionGF83.40-P-9990P

Convenience automatic air conditioning (C-AAC) system component overview, location/task/design/function - GF83.40-P-9996P

Model 203.0 /2 /7 up to 31.5.01 with CODE (581) Automatic air conditioning

Model 203.0 /2 /7 as of 1.6.01 with CODE (581) Comfort automatic air conditioning

Control and operating unit comfort automatic air conditioning location/taskOn vehicles up to 23.4.04GF83.40-P-2181PP
On vehicles as from 24.4.04 with code (581b) Comfort automatic air conditioningGF83.40-P-2181PQ
Front SAM control unit with fuse and relay module location/task/designGF54.21-P-4108PP
Front driver-side door control unit, location/task/ design/functionGF72.29-P-4105PP
Front passenger's door control unit, location/ task/design/functionGF72.29-P-4106PP
Rear door control unit, location/ purpose/design/functionOnly on model 203.0/2GF72.29-P-4102PP
Electronic ignition switch control unit, location/ task/design/functionGF80.57-P-4102PP
Overhead control panel control unit, location/ task/designGF82.20-P-4110A
Air ducting, location/task/functionGF83.10-P-2182P
Actuator motors for comfort automatic air conditioning, location/task/functionGF83.40-P-2183P
Blower motor, location/task/functionGF83.10-P-2140P
Blower regulator, location/task/functionGF83.10-P-2141P
Rear blower motor Location/task/functionOn vehicles as from 1.6.01 with code (581b) Comfort automatic air conditioningGF83.10-P-2168P
Control unit for rear blower motor, location/task/design/functionOn vehicles as from 1.6.01 with code (581b) Comfort automatic air conditioningGF83.10-P-2169P
Heating system heat exchanger, location/ purpose/functionGF83.20-P-2108P
Heater water circulation pump, location/task/ functionGF83.20-P-2109P
Dust filter, location/task/functionGF83.10-P-2142P
Activated-carbon filter, location/task/ functionGF83.30-P-2118P
Convenience air conditioner housing, location/ task/design/functionGF83.40-P-2170P
Electric fan motor/air conditioning system, location/task/functionGF83.40-P-2151P
Condenser location/task/functionGF83.40-P-2152P
Evaporator location/task/design/functionGF83.40-P-2121P
Fluid reservoir location/task/design/ functionGF83.40-P-2122P
Expansion valve, location/task/design/ functionGF83.40-P-2123P
Air conditioning coolant temperature sensor location/task/functionGF83.40-P-2155P
Refrigerant pressure and temperature sensor location/task/functionGF83.40-P-2171P
Refrigerant compressor, location/ task/design/functionGF83.55-P-2100P
Refrigerant compressor control valve location/ task/functionGF83.55-P-2102P
Belt pulley, location/task/design/functionGF83.55-P-2103P
Pressure relief valve, location/task/ functionGF83.55-P-2104P
Evaporator core temperature sensor, location/ task/functionGF83.57-P-2109P
Outside temperature sensor, location/ task/functionOn vehicles up to 23.4.04GF83.57-P-2110P
In vehicles as of 24.4.04GF83.57-P-2110PP
Multifunction sensor location/task/ functionGF83.10-P-2148P
Sun sensor location/task/functionGF83.57-P-2111P
Convenience automatic air conditioning (C-AAC) functional description table of contentsGF83.40-P-0996P

Identifying Refrigerant Compressor Components. Scheme 1

Scheme 1: Identifying Refrigerant Compressor Components

Function

The rotary movement of the belt pulley (1) is transmitted via the refrigerant compressor shaft (13) to the stop plate (12), which is permanently fastened to the refrigerant compressor shaft (13) by way of a press fit.

The rotation of the stop plate (12) is transmitted to the swash plate (4) by means of a hinged mechanism.

Conversion of the swash plate's (4) rotary motion into the oscillating motion of the seven pistons (6) takes place via two sliding shoes each (11).

The evaporation tank on the pressure side (5) and evaporation tank on the suction side (7) reduce gas pulsation in the refrigerant compressor by providing for uniform refrigerant flow. This helps to prevent noise in the compression process

Volume control

The refrigerant compressor control valve (8) has a corresponding control current applied to it to match the output requested. This in turn enables the compression volume to be regulated between 2 and 100 %.

The position of the swash plate (4) is determined through monitoring, processing and evaluation of the following automatic air conditioning controlled variables

  1. Pressure in the crankcase (2) of the refrigerant compressor
  2. Diaphragm pressure in the refrigerant compressor control valve (8) (approx. 2 bar)
  3. Suction pressure of refrigerant compressor

The change in suction pressure which is dependent on the control current on the refrigerant compressor control valve (8) induces a change of pressure in the crankcase (2) and thus a corresponding adjustment of the swash plate (4).

Automatic air conditioning (AAC [KLA]) OFF

If the automatic air conditioning is regulated or manually switched off, the refrigerant compressor control valve (8) is completely opened. Refrigerant flows unobstructed over the high pressure side into the crankcase (2). This in turn leads to a rapid pressure rise in the crankcase (2). The coil body (10), for closing the refrigerant compressor, is displaced here to the right against the valve plate (9) and thus stops the flow of refrigerant over the intake side.

Refrigerant compressor lubrication when automatic air conditioning switched off

An internal lubrication circuit ensures the lubrication supply for all moving parts.

Lubrication is ensured at a minimum refrigerant compressor volumetric flow by means of two valves being regulated. In doing so, the refrigerant is transported together with the compressor oil located in the crankcase (2) over the bored refrigerant compressor shaft (13). The mixture enters the cylinder housing, where it is compressed and then pumped into the refrigerant circuit.

Identifying Refrigerant Compressor Components. Scheme 2

Scheme 2: Identifying Refrigerant Compressor Components