The Different Types of Carburetors

by Mark Orwell
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Engines in modern automobiles are complex and intricate machines. The carburetor is just one of the parts that make up the modern-day engine. It is responsible for mixing fuel and air into a combustible compound, regulating the ratio of those two ingredients and controlling the speed of the automobile. Different engines require the use of different carburetor types.

One-, Two-, and Four-Barrel Carburetors

There are various ways to classify the different types of carburetors, and one such way is to count the number of barrels they contain. A barrel is simply a container or passageway used to mix air and fuel. Carburetors come in one-, two- and four-barrel models. Smaller engines use one-barrel carburetors because they don't require as much power to operate. A larger carburetor would be too massive, as well. Two-barrel carburetors are the most common. Four-barrel carburetors are used with high-performance engines. Most of the time, only two barrels are used, but the additional two come into play when more horsepower is needed. Racecars are an example of the type of vehicle that would employ a four-barrel carburetor.

Two-Barrel Subtypes

Two-barrel carburetors can be further divided into two subtypes. The first type is a model where each barrel contains all the necessary circuitry of a carburetor and a single common float chamber. The throttles in this type of carburetor can both be opened simultaneously. The second type is a bit more complicated. The two barrels share a single set of circuitry between the two, and each throttle opens at different times. The first barrel is used at idle to medium speeds, supplying its own mixture of air and fuel. The second barrel opens its throttle when the car moves into high speeds, requiring full throttle use. The second barrel at this time supplies additional air-fuel mixture to the engine's cylinders.

Side and Down Draft Carburetors

Other types of carburetors are categorized based on how air flows into them. Side draft carburetors allow air to flow in horizontally and are easily mounted on engines when little space is available above them. Down draft carburetors, on the other hand, are set on top of the engine. They have larger barrels, and use gravity to help move the air-fuel mixture into the various engine cylinders.

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