Topics:
Roots Supercharger:
A roots supercharger (also known as a supercharger) provides additional air supply to the engine. The cylinder is filled with overpressure, allowing for the right amount of injection and correct ignition timing to achieve higher power and torque. The advantage of a roots supercharger compared to a turbo is that it builds pressure at low RPM. A turbo requires exhaust gases to build up pressure, which is also known as turbo lag. A roots supercharger is driven by a belt and does not suffer from this delay.
The disadvantage of this supercharger is that engine power is lost because it is mechanically driven. This disadvantage is not present with a turbo, resulting in a greater overall power gain with a turbo.
The two lobes in the image on the right rotate in opposite directions. They do not touch each other during rotation. Because the upper lobe rotates clockwise and the lower lobe counterclockwise, air is carried along the top and bottom of the supercharger housing. This air contributes to the pressure filling of the engine.
There are engines that use both a roots supercharger and a turbocharger, such as the TSI engines from Volkswagen. (The turbo is a separate component and is described in detail on the Turbo page). These TSI engines have higher torque and power at low RPMs, thanks to the supercharger. At low RPM, the supercharger is in operation, which helps the turbocharger to start and ensures cylinder filling at low speeds so that the engine is provided with enough torque under 2000 RPM. At a certain engine speed (around 2000 RPM), the supercharger is disengaged, and the turbocharger builds pressure. The turbocharger provides more power at high RPM. Due to the combination of supercharger and turbocharger, turbo lag is eliminated.
The compressed air goes through the supercharger or bypass valve to the turbo and from the turbo through the intercooler to the intake manifold.
Intercooler:
The temperature of the compressed air can become very warm (warmer than 60 degrees Celsius). For better cylinder filling and consequently better combustion, it is necessary for the air to cool sufficiently. The intercooler provides this cooling. The intercooler is a separate component and is therefore described in detail on another page; see the page Intercooler.
