Features of the turbocharging system (VW Passat B4)

The boost is achieved by a turbocharger running on the energy of the exhaust gases. The boost air on the 1Z and AFN engines is cooled in an air-to-air heat exchanger. The turbocharger is a Garett brand. The boost pressure of the 1Z engine is 0.5-0.6 kgf/cm², while for the AFN engine it is 1.7-2.4 kgf/cm². The boost pressure is limited by an electromagnetic valve based on ECU signals. The resistance of the valve winding for the 1Z engine is 25-45 Ohm. For the AFN engine it is 14-20 Ohm.

Features of the turbocharger device of the "AFN" engine

A variable geometry turbocharger consists of a compressor and a gas turbine, the working wheels of which are mounted on a single shaft called a rotor. In the volute of the turbine housing, variable-angle blades are mounted on a movable ring, which provide a change in the flow section of the turbine nozzle apparatus and, consequently, the rotor speed. At low engine speeds, the angle of inclination of the movable blades is minimal, and at high speeds, it is maximal. The rotation of the movable ring and, accordingly, the change in the angle of inclination of the movable blades are carried out by means of a rod and a rod, which are controlled by a pneumatic drive depending on the operating pressure of the compressor. Due to the fact that this pressure depends on the engine speed, the angle of inclination of the movable blades, which determines the flow section of the turbine nozzle apparatus, also depends on the crankshaft speed.