How the turbocharger boost works
As a result of the operation of the turbocharger, air is forced under pressure into the engine cylinders. The turbocharger has two impellers attached to the ends of the common shaft. The first to come into action is the impeller of the turbo (so-called ‘hot’) part, which begins to rotate under the influence of the energy of the exhaust gases coming to it. From it, the common shaft begins to spin, and the motion is transferred to the ‘cold’ impeller of the compressor at the other end. The impeller rotating at high speed begins to strongly suck in the air surrounding it, which is supplied under pressure through the air pipes to the engine cylinders. Due to this, a larger amount of air-fuel mixture enters the cylinders than with the usual discharge created by the movement of the piston. There is the excess pressure that enters the engine cylinders, and this is a boost or boost of the turbo.
Why do I need a turbo boost
- increased power
- fuel economy
- eco-friendly driving
The boost of the turbo increases the power of the motor, without requiring a large volume and high RPM. Thanks to the boost created by the turbocharger, there is no need to buy a car with a larger engine for the sake of more power. Driving with a small-litre engine, in turn, is more fuel-efficient and, therefore, more environmentally friendly.
What controls the power of the boost
Wastegate
Pressure regulators – bypass and westgate – play an important role in controlling the boost power. Their task is to ensure an optimal air pressure that does not exceed the permissible maximum. To ensure that the exhaust gases do not spin the turbo wheel more than necessary and do not create excessive pressure, the westgate installed on the hot part of the turbo releases excess gases into the atmosphere.
Bypass and blow-off
Another nuance is that when the gas pedal is released, the compressor impeller does not stop immediately and continues to pump air for some time by inertia. The throttle valve blocks it and does not allow it into the engine. As a result, an unclaimed excess pressure remains between the intake manifold and the cold impeller of the compressor. In order for it not to go back to the compressor impeller (which threatens to break it), the blow-off valve releases excess air into the atmosphere. Another type of valve, a bypass, directs unused excess air back to the turbo inlet.
ECU
Most modern turbocharged cars are equipped with electronic control units. They determine and maintain the parameters of optimal boost and control the geometry of the turbo in the case of a turbocharger with variable geometry.