Types of carburetor

There are three general types of carburettor depending on the direction of flow of air.

1. Up draught type 
2. Down draught type
3. Cross draught type 

In up draught type, carburettor air enters at the bottom and leaves at the top so that the direction of its flow is upward. 

In down draught type carburettor air and mixture generally, follow a downward course. It is placed at a level higher than the inlet manifold. 

A cross draught type carburettor consists of horizontal mixing tube with a float chamber on one side of it.

Apart from that, some other types of carburettors are :

1. Constant chock carburettor 
2. Constant vacuum carburettor
3. Multiple venturi carburettor
4. Multijet carburettor 

The air and fuel flow areas are always maintained to be constant in a constant chock carburettor. The pressure difference causes the flow of fuel and air are being varied as per the demand on the engine. 

Example : 

1. Solex carburettor 
2. Zenith carburettor 

The air and fuel flow areas are being varied as per the demand on the engine and the vacuum maintained to be always same in a constant vacuum carburettor.

Example :

1. SU carburettor 
2. Carter carburettor 

In multiple venturi carburettor used double or triple venturi. These ventures arranged in a series, are used in certain carburettors. There are three venturi namely, the primary venturi, the secondary venturi and the main venturi.  The output of the primary venturi is placed in the throat of the secondary venturi. The outlet of the secondary venturi is situated in the throat of the main venturi. You can check it out the advantages of multiple venturi carburettor. 

In our simple carburettor is called single barrel carburettor. Whereas a dual carburettor has two barrels so-called as a multijet carburettor. Each of these two barrels in a dual carburettor contains a fuel jet, a venturi tube, and idling system and chock and a throttle. 

Example: Passenger cars with six or more cylinders are provided with dual carburettors.