Turbocharger (VW Passat B3)

In a turbocharger, two wheels, a turbine wheel and a compressor wheel, are installed on one shaft and are located in housings separated from each other.

Exhaust gases are used to drive the turbine wheel. They accelerate the supercharger shaft to a rotation speed of 120,000 1/min. Since the wheels have a common rotor, the compressor wheel rotates at the same speed and pumps fresh air into the engine cylinders.

In addition to the engine power, the torque also increases when using a turbocharger. The prerequisite for this is that the compressor shaft rotates at a sufficient speed, thereby guaranteeing a decent filling factor. As a rule, a noticeable boost pressure is already achieved at an engine crankshaft speed of about 2500 rpm.

To further improve cylinder filling, a charge air cooler is located between the turbocharger and the engine intake port, which cools the pre-compressed air. This increases the power output, since the cold air contains more oxygen due to its higher density.

In the turbocharged engine with an output of 81 kW/110 hp, the variable turbocharger provides additional power. For this purpose, the turbine is equipped with variable guide vanes, which are continuously controlled by the engine control unit via an electromagnetic valve and a vacuum diaphragm mechanism. This ensures that the optimum boost pressure is created at all times, which results in higher torque and correspondingly increased power, especially at low engine speeds.

The turbocharger is an extremely precisely manufactured unit. Therefore, in case of repair, it is recommended to contact a specialist. As a rule, if a defect occurs, the turbocharger is replaced as an assembly.

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