What is a carburetor and how does it function?

A carburetor is a device that functions to mix vaporized fuel and air in a specific ratio to make it combustible for an internal-combustion engine. The carburetor maintains a stoichiometric mixture of fuel and airs that result in optimum fuel efficiency and engine performance. If the amount of air intake is less than required than the engine will be less efficient and black smoke will be produced causing pollution to the environment as well. If the amount of fuel injected is less than required than the engine will produce less power and the engine can overheat as well.

Working Principle

A carburetor functions on Bernoulli’s Principe. Bernouli’s equation is stated as follows:-

In the above equation the first term denotes the static pressure while the section term denotes the dynamic pressure. According to Bernoulli’s Principle the static pressure and the dynamic pressure are inversely proportional. The throttle actuates the air intake mechanism of the carburetor. The amount of fuel injected into the carburetor airstream is dependent upon the speed of the airstream.

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The design of a carburetor consists of a tube with a venturi at which a vacuum is created. There is a small opening in the venture that is called jet. The purpose of jet is to deliver fuel from the float chamber. The throttle valve is located downstream of the jet, it opens when the accelerator pedal is engaged. This throttle valve restricts how much air enters the carburetor. The air enters this tube via passing through the filter which is used to filter the incoming air from dust particles. The vacuum created in the venturi caused the fuel to be injected from the float chamber via jets. The float chamber is maintained at ambient pressure. The faster the filtered air comes in through the carburetor throat, the lower the pressure in the venturi. This leads to a higher pressure difference between the venturi and the float chamber, and thus more fuel flows out of the jet and mixes with the airstream.

Manufacturing

A carburetor is manufactured using Aluminum with some steel parts. The manufacturing of carburetor requires great accuracy therefore it requires computer navigated machining also known as CNC machines. The initial block is manufactured using casting with margins for machining. After that various machining operations are carried out. Different components are assembled to complete the carburetor.