The automotive industry has developed many types of air blowers; some of them are widely used to this day, others have gone down in history due to design imperfections.
The air blower in a car engine is an integral part of the pressurization system. The task of the supercharger is to create increased pressure in the intake tract. This device gets its name from the connection to the crankshaft and the airflow due to the pressure difference. Today, several types of structures are used in the world, differing in design.
Centrifugal blowers
These units are the most demanded today, due to their affordable price and simple device. The main part of a centrifugal blower is a cone-shaped impeller (impeller) with blades. The principle of operation is simple: air enters through a tapering channel and enters the impeller blades, which throw the air flow towards the casing. The latter has a diffuser through which air is pushed into a cochlear air tunnel. As a result, the required pressure is generated at the outlet.
The design of a centrifugal blower requires a drive to connect the unit to the engine crankshaft. On Russian VAZs, a direct drive is usually used, which implies fastening the structure to the crankshaft flange. At least, a belt drive is used, which uses a flat, toothed or V-belt. The electric method of rotation of the supercharger is gaining popularity, requiring a separate electric motor; and it is quite rare to find a chain drive, in which the transmission of rotation is carried out by means of a metal chain.
Roots and Lysholm blowers
The Roots design belongs to the class of volumetric devices and resembles a gear oil pump. The oval body contains a pair of rotors rotating in opposite directions and fixed on axles (communication is carried out by means of gears). At the same time, there is a small gap between the rotors and the housing. Air entering the inside of the housing enters the rotor cams, which throw the flow into the external discharge line. Therefore, this type of blower is sometimes referred to as an external compression compressor.
Structures of the Lisholm type in terms of the device resemble a meat grinder with a pair of screws, which have mutual engagement. The rotors capture air and begin to rotate towards each other, causing the air to be pushed forward like minced meat in a meat grinder. The main advantage of Lisholm type designs compared to Roots is the presence of internal compression, which provides greater pumping efficiency.
