We need something in our vehicles to mix the air-fuel mixture, by using this mixture the vehicles move. Carburetor are used for this purpose. But now-a-days cars do not use carburetor, they use Fuel-injector for a better and efficient mixture of air and fuel.
What is Carburetor
It is a tube that allows air and fuel into the engine through valves, mixing them together in different amounts to suit a wide range of different driving conditions.
It was first developed by automobile pioneer (and Mercedes founder) Karl Benz (1844–1929).
How it works
The early carburetors where simple, but as the driving condition changed they became more complex. There is a large vertical pipe above the cylinders The atmospheric air is sucked in through this pipe and passes through a narrow kink in middle called has venturi. Because of venturi it makes the air flow faster and causes the pressure to fall, this falling pressure of air creates the sucking effect and draws fuel out the fuel pipe which is joined on the side of the carburetors.
The mixture of air-fuel is just what we need but how can you adjust the mixture into the cylinder? First we have throttle valve beneath the venturi, as the throttle valve opens, more air is flown through the carburetor and drags more fuel from the fuel pipe. With more fuel and air flowing in cylinder the engine generates more energy and car moves faster.
The second valve, choke valve which is helped in cold start and is above the venturi. This valve regulates the amount of air flowing in the carburetor, if the choke is closed very less amount of air passes and more of fuel is sucked in, which generates rich fuel mixture.
There is a mini fuel tank beside the carburetor which has a valve and a float. Through this tank the fuel pipe is attached to carburetor. As the chamber feeds the fuel to the carburetor, the fuel level in the tank sinks and the float level drops. When the float drops to a certain level, it opens a valve allowing fuel into chamber from the main fuel tank. Once the float rises the valves closes and the process continues.
Pros and Cons
- Emissions and fuel economy. Carburettor is not an efficient way of pumping fuel and air into the cylinder. It has pumping loss and the mixture is not evenly spread out throughout all cylinder properly. Fuel injection injects fuel into individual cylinder. Fuel injection is more precisely controlled, results in more efficient use of fuel, reduced fuel consumption and fewer emissions, which is the main reason it began to replace the carburetor in the 1970s.
- Power and performance. Again, because fuel injection and modern electronic controls are more accurate, fuel delivery can be tuned to match driver demand. Carburetors are precise, but not accurate, in that they cannot account for changes in air or fuel temperature or atmospheric pressure.
Read my fuel injector post you will get idea of what is the difference between carburetors and fuel injector. If you guys suggest I will write a post of difference of carburetors and fuel injector separately.
Also published on Medium.