Info-Authority.com: Carburetors

A carburetor is a mechanism designed to regulate the amount of fuel being drawn into the engine of an automobile or other device powered by internal combustion. The amount of fuel required by an engine varies depending on its current activity: very little needs be transferred when the engine is idling; a great deal more is required when it is running full throttle. The purpose of the carburetor is thus to provide the amount of fuel appropriate to the engine's need. This regulation prevents the engine from smoking or stalling due to an excess of fuel (or simply wasting it), while still ensuring that there is still sufficient fuel for the engine to run smoothly.

Carburetor Performance

A carburetor's design is relatively simple, being little more than a tube in which two closeable plates are placed to control the flow of fuel. Fuel is absorbed through the tube and into the engine by means of a vacuum placed at the tube's side, and the tube itself is tapered at the end approaching the engine to promote this vacuum flow. The strength of the vacuum determines the amount of fuel drawn into the engine, and the strength of the vacuum itself is determined by the position of the plates. When the interior plate, also known as a throttle plate, is almost closed, there is little air rushing through the tube of the carburetor and thus little vacuum; this is the engine in idle mode. When the throttle plate is thrown open, the air is allowed to rush through, causing a great deal of vacuum flow, enabling the engine to take in that much more fuel, and powering it accordingly. For maximum fuel injection—for example, to start the engine “cold”—the tube is sealed at the far end by means of a choke plate. This creates extremely strong suction within the carburetor's interior and forces a large amount of fuel into the system, thereby jumpstarting the engine into motion.

A large flow of fuel mixed with the carburetor's intake of air is commonly referred to as a “rich” mixture, while a small flow is called “lean." Rich mixtures provide additional power, but at the expense of more waste, pollution, and engine strain.

Carburetors and Automobiles

Carburetors are rarely found in newer automobiles, having been phased out since the 1980s by more sophisticated fuel-injection systems which use computerized sensors to do the carburetor's task more efficiently. However, due to their small size and lack of complexity, carburetors are still commonly found in simple gas-powered devices such as chainsaws and lawn mowers, and also in most motorcycles, although there has recently been a trend in motorcycles to replace carburetors with fuel-injection systems as well.

Over the years, there has been speculation about the potential for more efficient carburetors using heated metallic catalysts, possibly of nickel or platinum. In theory these designs could yield up to triple the efficiency of current carburetors, while emitting less pollution. However, none of these designs has ever come to fruition.

By Matthew Ingalls




	Carburetors A carburetor is a mechanism designed to regulate the amount of fuel being drawn into the engine of an automobile or other device powered by internal combustion. The amount of fuel required by an engine varies depending on its current activity: very little needs be transferred when the engine is idling; a great deal more is required when it is running full throttle. The purpose of the carburetor is thus to provide the amount of fuel appropriate to the engine's need. This regulation prevents the engine from smoking or stalling due to an excess of fuel (or simply wasting it), while still ensuring that there is still sufficient fuel for the engine to run smoothly. Carburetor Performance A carburetor's design is relatively simple, being little more than a tube in which two closeable plates are placed to control the flow of fuel. Fuel is absorbed through the tube and into the engine by means of a vacuum placed at the tube's side, and the tube itself is tapered at the end approaching the engine to promote this vacuum flow. The strength of the vacuum determines the amount of fuel drawn into the engine, and the strength of the vacuum itself is determined by the position of the plates. When the interior plate, also known as a throttle plate, is almost closed, there is little air rushing through the tube of the carburetor and thus little vacuum; this is the engine in idle mode. When the throttle plate is thrown open, the air is allowed to rush through, causing a great deal of vacuum flow, enabling the engine to take in that much more fuel, and powering it accordingly. For maximum fuel injection—for example, to start the engine “cold”—the tube is sealed at the far end by means of a choke plate. This creates extremely strong suction within the carburetor's interior and forces a large amount of fuel into the system, thereby jumpstarting the engine into motion. A large flow of fuel mixed with the carburetor's intake of air is commonly referred to as a “rich” mixture, while a small flow is called “lean." Rich mixtures provide additional power, but at the expense of more waste, pollution, and engine strain. Carburetors and Automobiles Carburetors are rarely found in newer automobiles, having been phased out since the 1980s by more sophisticated fuel-injection systems which use computerized sensors to do the carburetor's task more efficiently. However, due to their small size and lack of complexity, carburetors are still commonly found in simple gas-powered devices such as chainsaws and lawn mowers, and also in most motorcycles, although there has recently been a trend in motorcycles to replace carburetors with fuel-injection systems as well. Over the years, there has been speculation about the potential for more efficient carburetors using heated metallic catalysts, possibly of nickel or platinum. In theory these designs could yield up to triple the efficiency of current carburetors, while emitting less pollution. However, none of these designs has ever come to fruition. By Matthew Ingalls Related Links: Wikipedia - Carburetor Wikipedia article on carburetors.