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7.4.2. Hydrotransformer

Fig. 6.12. Elements (AKP), available after removal of the central console: 1 lamp of illumination of the coulisse of switching; 2 – cover; 3 – parking mode clamp; 4 – switching mechanism

In AKP between a number of planetary mechanisms and the engine the hydrotransformer (the hydrodynamic converter of torque) which serves for torque transmission of the engine by means of the ATF liquid (Automatic Transmission Fluid) circulating in his working cavities is located. The hydrotransformer consists of the pump, the turbine and the reactor. These elements are concluded in the general casing in such a way that form the closed oil circulation. The engine brings a pump wheel which transforms mechanical energy to hydraulic into rotation. The turbine connected to main shaft AKP transforms this energy to torque. The reactor is located between the pump and the turbine which always have a certain difference in the frequency of turns. At start of the car it is maximum and decreases at increase in speed of the movement. Thus, at a certain measure there is always a skidding mode.

Provisions of the lever of the selector.
      "Р" (parking). In this situation main shaft AKP is blocked. Blocking is provided with a special gear wheel with a cam. Gear wheels in this mode do not rotate and remain blocked. At the parking of the car the lever of the selector should be transferred to situation "P" only at a full stop of the car.
      "R" (reverse gear). For inclusion of this transfer the car has to stand, and the engine — to idle. If during advance the lever is incidentally transferred to situation "R", the special safety valve reacting to the movement blocks turning on of the reverse gear.
      "N" (neutral transfer). At this position of the lever of the selector connection between the bringing gear wheels and the engine is opened. But unlike the P mode of a gear wheel are not blocked as all knots of coupling are switched off, and any gear wheel does not keep.
      "D" (movement). In this situation hydraulic pressure begins to influence coupling of forward transfers thanks to what the torque from the engine is transferred to driving gear wheels. The car at the same time begins to move forward. It is possible to stop it easy pressing a brake. When pressing a pedal of an accelerator the usual mode of the movement with all transfers works.
      "2" (2nd transfer). This mode is intended for overcoming slopes and rises or the movement on snow and ice. When pressing a pedal of an accelerator remains included the 2nd transfer. At an otpuskaniye of a pedal there is a braking the engine.
       "1" (1st transfer). This mode is used only for steep slopes and slopes. When pressing a pedal of an accelerator remains included the 1st transfer. At an otpuskaniye of a pedal there is a strong braking the engine.
       Selector lever lock. For transfer of the lever to the R and 2 modes (except for the transfer from situation "1" to situation "2"), and also inclusions and switching off of the P mode it is necessary to press the button sideways of the selector lever. The engine can be launched only in situation "P" or "N". At the included R, D, 1 or 2 modes the protecting device in AKP interferes with launch of the engine (fig. 6.12).
        Two reverse gears. The switch on the central console the driver can make active the special winter mode. It significantly differs from the mode of the S standard. (So, for example, if necessary the start on snow or ice is made on the 2nd transfer). For the same smooth driving by a backing the 2nd reverse gear with the increased transfer number turns on. Changes of transfers happen in the winter mode ("W") on lower turns of the engine. The main reactions of AKP to traffic conditions (its switchings), for example, at the movement uphill, remain. And on the contrary, the AKP electronic system in the W mode blocks the dynamic reactions of AKP to "full gas" ("Kick-fast") put in the program or a sharp otpuskaniye of a pedal of an accelerator ("Fast-off").

Care at towage
If your Mercedes is not got, its pushing or towage will not help to launch the engine. The hydrotransformer cannot provide at the idle engine feedback with it. Therefore it is necessary to try to start at first the engine by means of starting wires.
It is possible to tow the car only forward, having installed the AKP selector lever in situation "N". During towage the AKP oil pump does not rotate while planetary mechanisms are given to rotation by the driveshaft. Therefore it is possible to tow the car only on distance no more than 50 km and with a speed of movement not higher than 50 km/h.