carburetor (redirected from Carborator)

carburetor (kär`byərā`tər, –bə–), part of a gasoline engine in which liquid fuel is converted into a vapor and mixed with a regulated amount of air for combustion in the cylinders. Land vehicles, boats, and light aircraft have a float carburetor, in which a float regulates the fuel level in a reservoir from which the fuel is sucked into the intake manifold at a restriction called a venturi. This venturi metering system controls the flow of a continuous pumped spray into the intake manifold downstream from the carburetor. When there is an individual spray for each cylinder and the injection is an intermittent, timed spurt, or is metered differently, the device is usually called a fuel injector, not a carburetor (see fuel injection).

---

carburetor

Device for supplying a spark-ignition engine with a mixture of fuel and air. Carburetors are used in small gasoline engines, such as lawn mowers and chainsaws. Once an essential component in all gasoline engines, automobile carburetors were displaced by electronic fuel injection systems from the late 1970s through 1990. Carburetors for automobile engines usually contained a storage chamber for liquid fuel, a choke, an idling jet, a main jet, an airflow restriction, and an accelerator pump. The quantity of fuel in the storage chamber was controlled by a valve actuated by a float. The choke, a butterfly valve, reduced the intake of air so that a fuel-rich charge was drawn into the cylinders when a cold engine was started. As the engine warmed up, the choke was gradually opened. Reduced pressure near the partially closed throttle valve caused the fuel to flow from the idling jet into the intake air. Further opening the throttle valve activated the main fuel jet. Then the venturi-shaped airflow restriction created reduced pressure, drawing fuel from the main jet into the airstream at a rate related to the airflow so that a nearly constant fuel-air ratio was obtained. The accelerator pump injected fuel into the inlet air when the throttle was opened suddenly. See also gasoline engine; venturi tube.

---

carburettor, carburetter (US), carburetor

a device used in petrol engines for atomizing the petrol, controlling its mixture with air, and regulating the intake of the air-petrol mixture into the engine

---

carburetor [′kär·bə‚red·ər]

(chemical engineering)

An apparatus for vaporizing, cracking, and enriching oils in the manufacture of carbureted water gas.

(mechanical engineering)

A device that makes and controls the proportions and quantity of fuel-air mixture fed to a spark-ignition internal combustion engine.

---

Carburetor

A device that controls the power output and fuel feed of internal combustion spark-ignition engines used for automotive, aircraft, and auxiliary services. Its duties include control of the engine power by the air throttle; metering, delivery, and mixing of fuel in the airstream; and graduating the fuel-air ratio according to engine requirements in starting, idling, and load and altitude changes. The fuel is usually gasoline or similar liquid hydrocarbon compounds, although some engines with a carburetor may also operate on a gaseous fuel such as propane or compressed natural gas. A carburetor may be classified as having either a fixed venturi, in which the diameter of the air opening ahead of the throttle valve remains constant, or a variable venturi, which changes area to meet the changing demand. See Automobile, Engine, Fuel system, Venturi tube

A simple updraft carburetor with a fixed venturi illustrates basic carburetor action (see illustration). Intake air charge, at full or reduced atmospheric pressure as controlled by the throttle, is drawn into the cylinder by the downward motion of the piston to mix with the unscavenged exhaust remaining in the cylinder from the previous combustion. A cylinder is most completely filled with the fuel-air mixture when no other cylinder is drawing in through the same intake passage at the same time. The fuel is usually metered through a calibrated orifice, or jet, at a differential pressure derived from the pressure drop in a venturi in the intake air passage.

Elements that basically determine air and fuel charges received by the engine through the carburetor