Bendix-Technico (Stromberg) 1-barrel downdraft carburetor model BXUV-3, with nomenclature

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A carburetor (North American spelling) or carburettor (Commonwealth spelling), is a device that blends air and fuel for an internal combustion engine. It was invented by Karl Benz before 1885^[1] and patented in 1886.^[2] It is colloquially called a carb (in North America and the United Kingdom) or carby (chiefly in Australia).^{[citations needed]} Image File history File links CarbNomenclature. ... Image File history File links CarbNomenclature. ... Image File history File links Question_book-3. ... The differences in the spellings of British English and American English are as follows: Spelling differences between U.S. usage on one side and British and Commonwealth usage on the other are generally more conspicuous than spelling differences within the Commonwealth. ... Air redirects here. ... For other uses, see Fuel (disambiguation). ... A colorized automobile engine The internal combustion engine is an engine in which the combustion of fuel and an oxidizer (typically air) occurs in a confined space called a combustion chamber. ... Karl Benz Karl Friedrich Benz, for whom an alternate French spelling of Carl is used ocassionaly, (November 25, 1844, Karlsruhe, Germany – April 4, 1929, Ladenburg, Germany) was a German engine designer and automobile engineer, generally regarded as the inventor of the gasoline-powered automobile. ... 1885 (MDCCCLXXXV) is a common year starting on Thursday of the Gregorian calendar (or a common year starting on Saturday of the 12-day slower Julian calendar). ... Year 1886 (MDCCCLXXXVI) was a common year starting on Friday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Wednesday of the 12-day slower Julian calendar). ...

The word carburetor comes from the French carbure, meaning 'carbide' [1]. To carburete means to combine with carbon. In fuel chemistry, the term has the more specific meaning of increasing the carbon (and therefore energy) content of a fuel by mixing it with a volatile hydrocarbon. Calcium carbide. ... For other uses, see Carbon (disambiguation). ... For other uses, see Carbon (disambiguation). ... Look up Hydrocarbon in Wiktionary, the free dictionary. ...

History and development

The carburetor was invented by the Hungarian engineer Donát Bánki in 1893. Frederick William Lanchester of Birmingham, England experimented early on with the wick carburetor in cars. In 1896 Frederick and his brother built the first petrol driven car in England, a single cylinder 5 hp (4 kW) internal combustion engine with chain drive. Unhappy with the performance and power, they re-built the engine the next year into a two cylinder horizontally opposed version using his new wick carburetor design. This version completed a 1,000 mile (1600 km) tour in 1900 successfully incorporating the carburetor as an important step forward in automotive engineering. Look up engineer in Wiktionary, the free dictionary. ... Donát Bánki (1859-1922) was a Hungarian mechanical engineer, inventor of (among many other things) the carburetor. ... Frederick William Lanchester (October 23, 1868 - March 8, 1946) was an English polymath and engineer who made important contributions to automotive engineering, aerodynamics and co-invented the field of operations research. ... This article is about the British city. ...

Carburetors were the usual fuel delivery method for almost all engines up until the mid-1980s, when fuel injection became the preferred method of automotive fuel delivery. In the US market, the last carbureted car was the 1991 Ford Crown Victoria Police Interceptor equipped with the 351 in³ (5.8 L) engine, and the last carbureted light truck was the 1994 Isuzu.^[3] Elsewhere, Lada cars used carburetors until 1996. In jurisdictions with little or no regulation of auto exhaust emissions, new vehicles such as those from Tata in India and the VW Citi in South Africa are still equipped with carburetors^{[citation needed]}. A majority of motorcycles still utilize carburetors due to lower cost, but as of 2005, many new models are now being introduced with fuel injection. Carburetors are still found in small engines and in older or specialized automobiles, such as those designed for stock car racing. // Multi Port Fuel injection is a means of metering fuel into an internal combustion engine. ... The Police Interceptor (often referred to simply as CVPI) is the law enforcement version of the 1999 and later Ford Crown Victoria. ... The Windsor engine is a 90-degree small-block V8 from Ford Motor Company. ... This article is about a truck manufacturer. ... For other uses, see Lada (disambiguation). ... Tata Motors Limited, formerly known as TELCO (TATA Engineering and Locomotive Company), is Indias largest passenger automobile and commercial vehicle manufacturing company. ... The VW Citi is a car produced by Volkswagen in South Africa. ... A motorcycle (or motorbike) is a two-wheeled vehicle powered by an engine. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... // Multi Port Fuel injection is a means of metering fuel into an internal combustion engine. ... Car redirects here. ... This article is about the sport of stock car racing. ...

Principles

The carburetor works on Bernoulli's principle: the faster air moves, the lower its static pressure, and the higher its dynamic pressure. The throttle (accelerator) linkage does not directly control the flow of liquid fuel. Instead, it actuates carburetor mechanisms which meter the flow of air being pulled into the engine. The speed of this flow, and therefore its pressure, determines the amount of fuel drawn into the airstream. Bernoullis Principle states that for an ideal fluid (low speed air is a good approximation), with no work being performed on the fluid, an increase in velocity occurs simultaneously with decrease in pressure or a change in the fluids gravitational potential energy. ... In an engine, the throttle is the mechanism by which the engines power is increased or decreased. ...

When carburetors are used in small aircraft with piston engines, special designs and features as found in e.g. the Bendix carburetor are needed to avoid fuel starvation under high g-forces. The Miss Shilling orifice was a very simple technical device made to counter engine cut-out in early Spitfire and Hurricane fighter aeroplanes during the Battle of Britain. ... The Bendix Corporation was founded in 1924 by the inventor Vincent Bendix. ...

Most carbureted (as opposed to fuel-injected) engines have a single carburetor, though some engines use multiple carburetors. Older engines used updraft carburetors, where the air enters from below the carburetor and exits through the top. This had the advantage of never "flooding" the engine, as any liquid fuel droplets would fall out of the carburetor instead of into the intake manifold; it also lent itself to use of an oil bath air cleaner, where a pool of oil below a mesh element below the carburetor is sucked up into the mesh and the air is drawn through the oil covered mesh; this was an effective system in a time when paper air filters did not exist. // Multi Port Fuel injection is a means of metering fuel into an internal combustion engine. ... A flooded engine is an internal combustion engine that has been fed an excessively rich air-fuel mixture that cannot be ignited. ... In automotive engineering, an intake manifold or inlet manifold is a part of an engine that supplies the fuel/air mixture to the cylinders. ... // A typical container of motor oil, with some in a glass. ... On an internal combustion engine, an air cleaner is a device that blocks dirt and debris from entering the induction system, where it might cause internal damage. ... Air filter in an Opel Astra car, top side=clean side Air filter in an Opel Astra car, bottom side=dust side Automotive air filter clogged with dust and debris. ...

Beginning in the late 1930s, downdraft carburetors were the most popular type for automotive use in the United States. In Europe, the sidedraft carburetors replaced downdraft as free space in the engine bay decreased and the use of the SU-type carburetor (and similar units from other manufacturers) increased. Some small propeller-driven aircraft engines still use the updraft carburetor design, however many use more modern designs such as the Constant Velocity (CV) Bing^(TM) carburetor^{[citation needed]}. SU carburetteurs (named for Skinners Union, the company which produced them) were a brand of sidedraft carburetor widely used in British (Triumph, MG) and Swedish (Volvo, Saab 99) automobiles for much of the twentieth century. ...

Operation

A high performance 4-barrel carburetor.

• Fixed-venturi, in which the varying air velocity in the venturi alters the fuel flow; this architecture is employed in most downdraft carburetors found on American and some Japanese cars
• Variable-venturi, in which the fuel jet opening is varied by the slide (which simultaneously alters air flow). In "constant depression" carburetors, this is done by a vacuum operated piston connected to a tapered needle which slides inside the fuel jet. A simpler version exists, most commonly found on small motorcycles and dirt bikes, where the slide and needle is directly controlled by the throttle position. These types of carburetors are commonly equipped with accelerator pumps to make up for a particular shortcoming of this design. The most common variable venturi (constant depression) type carburetor is the sidedraft SU carburetor and similar models from Hitachi, Zenith-Stromberg and other makers. The UK location of the SU and Zenith-Stromberg companies helped these carburetors rise to a position of domination in the UK car market, though such carburetors were also very widely used on Volvos and other non-UK makes. Other similar designs have been used on some European and a few Japanese automobiles. These carburetors are also referred to as "constant velocity" or "constant vacuum" carburetors. An interesting variation was Ford's VV (Variable Venturi) carburetor, which was essentially a fixed venturi carburetor with one side of the venturi hinged and movable to give a narrow throat at low rpm and a wider throat at high rpm. This was designed to provide good mixing and airflow over a range of engine speeds, though the VV carburetor proved problematic in service.

Under all engine operating conditions, the carburetor must: A Venturi meter is shown in a diagram, the pressure in 1 conditions is higher than 2, and the relationship between the fluid speed in 2 and 1 respectively, is the same as for pressure. ... SU carburetteurs (named for Skinners Union, the company which produced them) were a brand of sidedraft carburetor widely used in British (Triumph, MG) and Swedish (Volvo, Saab 99) automobiles for much of the twentieth century. ... Volvo Cars is the luxury car maker using the Volvo Trademark. ...

• Measure the airflow of the engine
• Deliver the correct amount of fuel to keep the fuel/air mixture in the proper range (adjusting for factors such as temperature)
• Mix the two finely and evenly

This job would be simple if air and gasoline (petrol) were ideal fluids; in practice, however, their deviations from ideal behavior due to viscosity, fluid drag, inertia, etc. require a great deal of complexity to compensate for exceptionally high or low engine speeds. A carburetor must provide the proper fuel/air mixture across a wide range of ambient temperatures, atmospheric pressures, engine speeds and loads, and centrifugal forces: Petrol redirects here. ... Centrifugal force (from Latin centrum centre and fugere to flee) is a term which may refer to two different forces which are related to rotation. ...

• Cold start
• Hot start
• Idling or slow-running
• Acceleration
• High speed / high power at full throttle
• Cruising at part throttle (light load)

In addition, modern carburetors are required to do this while maintaining low rates of exhaust emissions. Vehicle emissions inspection station Automobile emissions control covers all the technologies that are employed to reduce the air pollution-causing emissions produced by automobiles. ...

To function correctly under all these conditions, most carburetors contain a complex set of mechanisms to support several different operating modes, called circuits.

Basics

A carburetor basically consists of an open pipe, a "throat" or "barrel" through which the air passes into the inlet manifold of the engine. The pipe is in the form of a venturi: it narrows in section and then widens again, causing the airflow to increase in speed in the narrowest part. Below the venturi is a butterfly valve called the throttle valve — a rotating disc that can be turned end-on to the airflow, so as to hardly restrict the flow at all, or can be rotated so that it (almost) completely blocks the flow of air. This valve controls the flow of air through the carburetor throat and thus the quantity of air/fuel mixture the system will deliver, thereby regulating engine power and speed. The throttle is connected, usually through a cable or a mechanical linkage of rods and joints or rarely by pneumatic link, to the accelerator pedal on a car or the equivalent control on other vehicles or equipment. Image File history File links This is a lossless scalable vector image. ... In automotive engineering, an intake manifold or inlet manifold is a part of an engine that supplies the fuel/air mixture to the cylinders. ... A butterfly valve is a type of flow control device, typically used to regulate a fluid flowing through a section of pipe. ... Invented by Frank Bowden, a bowden cable is a type of flexible cable used to transmit mechanical force or energy by the movement of an inner cable (most commonly of steel or stainless steel) relative to a hollow outer cable housing. ... Hillman Imp, with the engine cover and the rear window lifted The Hillman Imp was a compact, rear-engined saloon (US: sedan) automobile manufactured under the Hillman marque by the Rootes Group (later Chrysler Europe) from 1963 to 1976. ... Note: This page needs to be cleaned up to be brought into conformance with the Manual of Style. ...

Fuel is introduced into the air stream through small holes at the narrowest part of the venturi. Fuel flow in response to a particular pressure drop in the venturi is adjusted by means of precisely-calibrated orifices, referred to as jets, in the fuel path.

Off-idle circuit

As the throttle is opened up slightly from the fully closed position, the throttle plate uncovers additional fuel delivery holes behind the throttle plate where there is a low pressure area created by the throttle plate blocking air flow; these allow more fuel to flow as well as compensating for the reduced vacuum that occurs when the throttle is opened, thus smoothing the transition to metering fuel flow through the regular open throttle circuit.

Main open-throttle circuit

As the throttle is progressively opened, the manifold vacuum is lessened since there is less restriction on the airflow, reducing the flow through the idle and off-idle circuits. This is where the venturi shape of the carburetor throat comes into play, due to Bernoulli's principle (i.e., as the velocity increases, pressure falls). The venturi raises the air velocity, and this high speed and thus low pressure sucks fuel into the airstream through a nozzle or nozzles located in the center of the venturi. Sometimes one or more additional booster venturis are placed coaxially within the primary venturi to increase the effect. In an engine, the throttle is the mechanism by which the engines power is increased or decreased. ... A Venturi meter is shown in a diagram, the pressure in 1 conditions is higher than 2, and the relationship between the fluid speed in 2 and 1 respectively, is the same as for pressure. ... Bernoullis Principle states that for an ideal fluid (low speed air is a good approximation), with no work being performed on the fluid, an increase in velocity occurs simultaneously with decrease in pressure or a change in the fluids gravitational potential energy. ...

As the throttle is closed, the airflow through the venturi drops until the lowered pressure is insufficient to maintain this fuel flow, and the idle circuit takes over again, as described above.

Bernoulli's principle, which is caused by the momentum of the fluid, is a dominant effect for large openings and large flow rates, but since fluid flow at small scales and low speeds (low Reynolds number) is dominated by viscosity, Bernoulli's principle is ineffective at idle or slow running and in the very small carburetors of the smallest model engines. Small model engines have flow restrictions ahead of the jets to reduce the pressure enough to suck the fuel into the air flow. Similarly the idle and slow running jets of large carburetors are placed after the throttle valve where the pressure is reduced partly by viscous drag, rather than by Bernoulli's principle. The most common rich mixture device for starting cold engines was the choke, which works on the same principle. In fluid mechanics, the Reynolds number is the ratio of inertial forces (vsρ) to viscous forces (μ/L) and consequently it quantifies the relative importance of these two types of forces for given flow conditions. ... For other uses, see Viscosity (disambiguation). ...

Power valve

For open throttle operation a richer mixture will produce more power, prevent detonation, and keep the engine cooler. This is usually addressed with a spring-loaded "power valve", which is held shut by engine vacuum. As the throttle opens up, the vacuum decreases and the spring opens the valve to let more fuel into the main circuit. On two-stroke engines, the operation of the power valve is the reverse of normal - it is normally "on" and at a set rpm it is turned "off". It is activated at high rpm to extend the engine's rev range, capitalizing on a two-stroke's tendency to rev higher momentarily when the mixture is lean. Knocking (also called pinking or pinging)— colloquially detonation—in internal combustion engines occurs when air/fuel mixture in the cylinder detonates or ignites prior to the timed pre-set conditions in the engines cylinder(s). ... The two-stroke cycle of an internal combustion engine differs from the more common four-stroke cycle by having only two strokes (linear movements of the piston) instead of four, although the same four operations (intake, compression, power, exhaust) still occur. ...

Alternative to employing a power valve, the carburetor may utilize a metering rod or step-up rod system to richen the fuel mixture under high-demand conditions. Such systems were originated by Carter Carburetor^{[citation needed]} in the 50's for the primary two venturis of their four barrel carburetors, and step-up rods were widely used on most 1-, 2-, and 4-barrel Carter carburetors through the end of production in the 1980s. The step-up rods are tapered at the bottom end, which extends into the main metering jets. The tops of the rods are connected to a vacuum piston and/or a mechanical linkage which lifts the rods out of the main jets when the throttle is opened (mechanical linkage) and/or when manifold vacuum drops (vacuum piston). When the step-up rod is lowered into the main jet, it restricts the fuel flow. When the step-up rod is raised out of the jet, more fuel can flow through it. In this manner, the amount of fuel delivered is tailored to the transient demands of the engine. Some 4-barrel carburetors use metering rods only on the primary two venturis, but some use them on both primary and secondary circuits, as in the Rochester Quadrajet.

Accelerator pump

The greater inertia of liquid gasoline, compared to air, means that if the throttle is suddenly opened, the airflow will increase more rapidly than the fuel flow, causing a temporary "lean" condition which causes the engine to "stumble" under acceleration (the opposite of what is normally intended when the throttle is opened). This is remedied by the use of a small mechanical pump, usually either a plunger or diaphragm type actuated by the throttle linkage, which propels a small amount of gasoline through a jet, wherefrom it is injected into the carburetor throat. This extra shot of fuel counteracts the transient lean condition on throttle tip-in. Most accelerator pumps are adjustable for volume and/or duration by some means. Eventually the seals around the moving parts of the pump wear such that pump output is reduced; this reduction of the accelerator pump shot causes stumbling under acceleration until the seals on the pump are renewed.

The accelerator pump is also used to prime the engine with fuel prior to a cold start. Excessive priming, like an improperly-adjusted choke, can cause flooding. This is when too much fuel and not enough air are present to support combustion. For this reason, carburetors are equipped with an unloader mechanism: The accelerator is held to the full extent of its travel while the engine is cranked, the unloader holds the choke open and admits extra air, and eventually the excess fuel is cleared out and the engine starts.

Choke

When the engine is cold, fuel vaporizes less readily and tends to condense on the walls of the intake manifold, starving the cylinders of fuel and making the engine difficult to start; thus, a richer mixture (more fuel to air) is required to start and run the engine until it warms up. A richer mixture is also easier to ignite.

To provide the extra fuel, a choke is typically used; this is a device that restricts the flow of air at the entrance to the carburetor, before the venturi. With this restriction in place, extra vacuum is developed in the carburetor barrel, which pulls extra fuel through the main metering system to supplement the fuel being pulled from the idle and off-idle circuits. This provides the rich mixture required to sustain operation at low engine temperatures.

In addition, the choke is connected to a "fast idle cam" or other such device which prevents the throttle from closing fully, which could starve the venturis of vacuum and cause the engine to stall. This also serves as a way to help the engine warm up quickly by idling it at a higher than normal speed. In addition, it increases airflow throughout the intake system which helps to better atomize the cold fuel and smooth out the idle.

In older carbureted cars, the choke was controlled by a cable connected to a pull-knob on the dashboard operated by the driver. In most carbureted cars produced from the mid 1960s onward (mid 1950s in the United States) it is usually automatically controlled by a thermostat employing a bimetallic spring, which is exposed to engine heat. This heat may be transferred to the choke thermostat via simple convection, via engine coolant, or via air heated by the exhaust. More recent designs use the engine heat only indirectly: A sensor detects engine heat and varies electrical current to a small heating element, which acts upon the bimetallic spring to control its tension, thereby controlling the choke. A choke unloader is a linkage arrangement that forces the choke open against its spring when the vehicle's accelerator is moved to the end of its travel. This provision allows a "flooded" engine to be cleared out so that it will start. Bi-metallic thermostat for buildings A thermostat is a device for regulating the temperature of a system so that the systems temperature is maintained near a desired setpoint temperature. ... thermocouple and Peltier_Seebeck effect. ... Electricity (from New Latin Ä“lectricus, amberlike) is a general term for a variety of phenomena resulting from the presence and flow of electric charge. ...

Some carburetors do not have a choke but instead use a mixture enrichment circuit, or enrichener. Typically used on small engines, notably motorcycles, enricheners work by opening a secondary fuel circuit below the throttle valves. This circuit works exactly like the idle circuit, and when engaged it simply supplies extra fuel when the throttle is closed.

Classic British motorcycles, with side-draft slide throttle carburetors, used another type of "cold start device", called a "tickler". This is simply a spring-loaded rod that, when depressed, manually pushes the float down and allows excess fuel to fill the float bowl and flood the intake tract. If the "tickler" was held down too long it also flooded the outside of the carburetor and the crankcase below, and was therefore a fire hazard.

Other elements

The interactions between each circuit may also be affected by various mechanical or air pressure connections and also by temperature sensitive and electrical components. These are introduced for reasons such as response, fuel efficiency or automobile emissions control. Various air bleeds (often chosen from a precisely calibrated range, similarly to the jets) allow air into various portions of the fuel passages to enhance fuel delivery and vaporization. Extra refinements may be included in the carburetor/manifold combination, such as some form of heating to aid fuel vaporization such as an early fuel evaporator. Fuel efficiency, in its basic sense, is the same as thermal efficiency, meaning the efficiency of a process that converts energy contained in a carrier fuel into energy or work. ... Vehicle emissions inspection station Automobile emissions control covers all the technologies that are employed to reduce the air pollution-causing emissions produced by automobiles. ...

Fuel supply

Float chamber

To ensure a ready mixture, the carburetor has a "float chamber" (or "bowl") that contains a quantity of fuel at near-atmospheric pressure, ready for use. This reservoir is constantly replenished with fuel supplied by a fuel pump. The correct fuel level in the bowl is maintained by means of a float controlling an inlet valve, in a manner very similar to that employed in toilet tanks. As fuel is used up, the float drops, opening the inlet valve and admitting fuel. As the fuel level rises, the float rises and closes the inlet valve. The level of fuel maintained in the float bowl can usually be adjusted, whether by a setscrew or by something crude such as bending the arm to which the float is connected. This is usually a critical adjustment, and the proper adjustment is indicated by lines inscribed into a window on the float bowl, or a measurement of how far the float hangs below the top of the carburetor when disassembled, or similar. Floats can be made of different materials, such as sheet brass soldered into a hollow shape, or of plastic; hollow floats can spring small leaks and plastic floats can eventually become porous and lose their flotation; in either case the float will fail to float, fuel level will be too high, and the engine will not run well unless the float is replaced. The valve itself becomes worn on its sides by its motion in its "seat" and will eventually try to close at an angle, and thus fails to shut off the fuel completely; again, this will cause excessive fuel flow and poor engine operation. Conversely, as the fuel evaporates from the float bowl, it leaves sediment, residue, and varnishes behind, which clog the passages and can interfere with the float operation. This is particularly a problem in automobiles operated for only part of the year and left to stand with full float chambers for months at a time; commercial fuel stabilizer additives are available that reduce this problem. mechanical fuel pump, fitted to cylinder head Electric fuel pump Petro-Canada Fuel Pump used to transfer fuel at a gas station. ... // These water valves are operated by handles. ... For other uses, see Toilet (disambiguation). ... Brazen redirects here. ...

Usually, special vent tubes allow air to escape from the chamber as it fills or enter as it empties, maintaining atmospheric pressure within the float chamber; these usually extend into the carburetor throat. Placement of these vent tubes can be somewhat critical to prevent fuel from sloshing out of them into the carburetor, and sometimes they are modified with longer tubing. Note that this leaves the fuel at atmospheric pressure, and therefore it cannot travel into a throat which has been pressurized by a supercharger mounted upstream; in such cases, the entire carburetor must be contained in an airtight pressurized box to operate. This is not necessary in installations where the carburetor is mounted upstream of the supercharger, which is for this reason the more frequent system. However, this results in the supercharger being filled with compressed fuel/air mixture, with a strong tendency to explode should the engine backfire; this type of explosion is frequently seen in drag races, which for safety reasons now incorporate pressure releasing blow-off plates on the intake manifold, breakaway bolts holding the supercharger to the manifold, and shrapnel-catching ballistic nylon blankets surrounding the superchargers. A supercharger (also known as a blower) is an air compressor used to force more air (and hence more oxygen) into the combustion chamber(s) of an internal combustion engine than can be achieved at ambient atmospheric pressure (natural aspiration). ... Drag racing is a form of auto racing in which cars attempt to complete a fairly short, straight and level course in the shortest amount of time. ...

If the engine must be operated in any orientation (for example a chain saw), a float chamber cannot work. Instead, a diaphragm chamber is used. A flexible diaphragm forms one side of the fuel chamber and is arranged so that as fuel is drawn out into the engine the diaphragm is forced inward by ambient air pressure. The diaphragm is connected to the needle valve and as it moves inward it opens the needle valve to admit more fuel, thus replenishing the fuel as it is consumed. As fuel is replenished the diaphragm moves out due to fuel pressure and a small spring, closing the needle valve. A balanced state is reached which creates a steady fuel reservoir level, which remains constant in any orientation. Alternative meaning: Chainsaw (computer program) A chainsaw (also spelled chain saw) is a portable mechanical, motorized saw. ... A needle valve is a type of valve usually used in flow metering applications. ...

Multiple carburetor barrels

Colombo Type 125 "Testa Rossa" engine in a 1961 Ferrari 250TR Spyder with six Weber two-barrel carburetors inducting air through 12 air horns; one individually adjustable barrel for each cylinder.

While basic carburetors have only one venturi, many carburetors have more than one venturi, or "barrel". Two barrel and four barrel configurations are commonly used to accommodate the higher air flow rate with large engine displacement. Multi-barrel carburetors can have non-identical primary and secondary barrel(s) of different sizes and calibrated to deliver different air/fuel mixtures; they can be actuated by the linkage or by engine vacuum in "progressive" fashion, so that the secondary barrels do not begin to open until the primaries are almost completely open. This is a desirable characteristic which maximizes airflow through the primary barrel(s) at most engine speeds, thereby maximizing the pressure "signal" from the venturis, but reduces the restriction in airflow at high speeds by adding cross-sectional area for greater airflow. These advantages may not be important in high-performance applications where part throttle operation is irrelevant, and the primaries and secondaries may all open at once, for simplicity and reliability; also, V configuration engines, with two cylinder banks fed by a single carburetor, may be configured with two identical barrels, each supplying one cylinder bank. In the widely seen V8 and 4-barrel carburetor combination, there are often two primary and two secondary barrels. Image File history File links Download high resolution version (2272x1704, 491 KB) 1961 Ferrari 250 TR 61 Spyder Fantuzzi 250 Colombo Testa Rossa engine From the Ralph Lauren collection on display at the Boston Museum of Fine Arts. ... Image File history File links Download high resolution version (2272x1704, 491 KB) 1961 Ferrari 250 TR 61 Spyder Fantuzzi 250 Colombo Testa Rossa engine From the Ralph Lauren collection on display at the Boston Museum of Fine Arts. ... Ferraris earliest cars used engines designed by Gioacchino Colombo, who had formerly designed Alfa Romeos for Enzo Ferrari. ... 1958 250 Testa Rossa from the Ralph Lauren collection 1961 250 TR Spyder Fantuzzi Serenissima version from the Ralph Lauren collection One of Ferraris most famous racing models was the 250 Testa Rossa of the 1950s and early 1960s. ... One complete cycle of a four cylinder, four stroke engine. ...

Multiple carburetors can be mounted on a single engine, often with progressive linkages; four two-barrel carburetors were frequently seen on high performance American V8s, and multiple four barrel carburetors are often now seen on very high performance engines. Large numbers of small carburetors have also been used (see photo), though this configuration can limit the maximum air flow through the engine due to the lack of a common plenum; with individual intake tracts, not all cylinders are drawing air at once as the engine's crankshaft rotates^[4].

Carburetor adjustment

Too much fuel in the fuel-air mixture is referred to as too rich, and not enough fuel is too lean. The mixture is normally adjusted by one or more needle valves on an automotive carburetor, or a pilot-operated lever on piston-engined aircraft (since mixture is air density (altitude) dependent). The (stoichiometric) air to gasoline ratio is 14.7:1, meaning that for each weight unit of gasoline, 14.7 units of air will be consumed. Stoichiometric mixture are different for various fuels other than gasoline. A needle valve is a type of valve usually used in flow metering applications. ... For other uses, see Density (disambiguation). ... Stoichiometry (sometimes called reaction stoichiometry to distinguish it from composition stoichiometry) is the calculation of quantitative (measurable) relationships of the reactants and products in chemical reactions (chemical equations). ... Petrol redirects here. ... This article is about the mathematical concept. ...

Ways to check carburetor mixture adjustment include: measuring the carbon monoxide, hydrocarbon, and oxygen content of the exhaust using a gas analyzer, or directly viewing the colour of the flame in the combustion chamber through a special glass-bodied spark plug sold under the name "Colortune"^[5] for this purpose. The flame colour of stoichiometric burning is described as a "bunsen blue", turning to yellow if the mixture is rich and whitish-blue if too lean. R-phrases , , , , S-phrases , , , , Flash point Flammable gas Related Compounds Related oxides carbon dioxide; carbon suboxide; dicarbon monoxide; carbon trioxide Supplementary data page Structure and properties n, εr, etc. ... General Name, symbol, number oxygen, O, 8 Chemical series nonmetals, chalcogens Group, period, block 16, 2, p Appearance colourless (gas) colourless (liquid) Standard atomic weight 15. ...

The mixture can also be judged after engine running by the state and color of the spark plugs: black, dry sooty plugs indicate a too rich mixture, white to light gray deposits on the plugs indicate a lean mixture. The correct color should be a brownish gray. See also reading spark plugs. Color is an important part of the visual arts. ... This article or section should include material from Spark gap A spark plug is an electrical device that fits into the cylinder head of some internal combustion engines and ignites compressed aerosol gasoline by means of an electric spark. ... This article is about the color. ... Soot, also called lampblack, Pigment Black 7, carbon black or black carbon, is a dark powdery deposit of unburned fuel residues, usually composed mainly of amorphous carbon, that accumulates in chimneys, automobile mufflers and other surfaces exposed to smoke—especially from the combustion of carbon-rich organic fuels in the... This article is about the color. ... Gray or grey is a color seen commonly in nature. ... For other uses, see Brown (disambiguation). ... This article or section should include material from Spark gap A spark plug is an electrical device that fits into the cylinder head of some internal combustion engines and ignites compressed aerosol gasoline by means of an electric spark. ...

In the early 1980s, many American-market vehicles used special "feedback" carburetors that could change the base mixture in response to signals from an exhaust gas Oxygen sensor. These were mainly used to save costs (since they worked well enough to meet 1980s emissions requirements and were based on existing carburetor designs), but eventually disappeared as falling hardware prices and tighter emissions standards made fuel injection a standard item. // An oxygen sensor is an electronic device that measures the proportion of oxygen (O2) in the gas or liquid being analyzed. ... // Multi Port Fuel injection is a means of metering fuel into an internal combustion engine. ...

Where multiple carburetors are used the mechanical linkage of their throttles must additionally be adjusted to synchronism for smooth engine running.

Catalytic carburetors

A catalytic carburetor mixes fuel fumes with water and air in the presence of heated catalysts such as nickel or platinum. This breaks the fuel down into methane, alcohols, and other lighter-weight fuels. The original catalytic carburetor was introduced to permit farmers to run tractors from modified and enriched kerosene. The U.S. Army also used catalytic carburetors with great success in World War II, in the North African desert campaign. It has been suggested that this article or section be merged into Catalysis. ... For other uses, see Nickel (disambiguation). ... General Name, Symbol, Number platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Standard atomic weight 195. ... Methane is a chemical compound with the molecular formula . ... This article does not cite any references or sources. ... Tractor vaporising oil is an internal combustion engine fuel that was commonly used for tractors in the UK until diesel engines became commonplace TVO was withdrawn from sale by UK suppliers in 1974. ...

While catalytic carburetors were made commercially available in the early 1930s, two major factors limited their widespread public use. First, the addition of additives to commercial gasoline made it unsuitable for use in engines with catalytic carburetors. Tetra-ethyl lead was introduced in 1932 to raise gasoline's resistance to engine knock, thereby permitting the use of higher compression ratios. Second, the economic advantage of using kerosene over gasoline faded in the 1930s, eliminating the catalytic carburetor's primary advantage. Tetra-ethyl lead (also known as TEL, lead tetraethyl and tetraethyllead) is a toxic organometallic chemical compound, with formula (CH3CH2)4Pb, which was once used as a gasoline (petrol) additive. ... Knocking (also called pinking or pinging)—technically detonation— in internal combustion engines occurs when fuel in the cylinder is ignited by the firing of the spark plug but burns too quickly, combusting completely before the optimum moment during the compression phase of the four-stroke cycle. ... Bold text The compression ratio is a single number that can be used to predict the performance of any engine (such as an internal-combustion engine or a Stirling Engine). ...

Manufacturers

Some manufacturers of carburetors are/were

• The AMAL Carburetter Company, supplier to the British motorcycle industry[2]
• Argelite, producer of Holley and Magneti Marelli carburetors for the Argentine market
• Autolite, a division of the Ford Motor Company from 1967 to 1973.
• Bendix Stromberg and Bendix Technico carburetors, used on vehicles made by Chrysler, IHC, Ford, GM, AMC, and Studebaker
• Bing Carburetor (used on motorcycles, mopeds, aircraft, boats)
• Briggs & Stratton, small engines (e.g. powered mowers)
• Carter carburetor, (used on numerous makes of vehicles, including those made by Chrysler, IHC, Ford, GM, AMC, and Studebaker, as well as on industrial and agricultural equipment and small engines
• Dell'Orto carburetors from Italy, used on cars and motorcycles
• Edelbrock AVS Carburetors
• Hitachi, Ltd. Hitachi carburetors, found on Japanese automobiles
• Holley, with usage as broad as Carter and Weber.
• Keihin, also common on Japanese and other motorcycles, a keiretsu group company affiliated with Honda
• Lectron carburators
• Mikuni, common on Japanese motorcycles, especially in the 1980s
• Motec Engineering - high performance updraft carburetors
• Pierburg carburetor, in Volvo, VW and Audi
• Rochester Products Division, USA (A General Motors subsidiary; also sold Weber/Magneti Marelli carburetors under license)
• Solex carburetor
• SU carburetor widely used on British Commonwealth and European-designed vehicles, presently manufactured by Burlen Fuel Systems
• Tecumseh Products Company, small engines (e.g. lawn mowers, snow blowers)
• Villiers UK Motorcycle and small engines
• Walbro and Tillotson carburetors for small engines Info
• Weber carburetor, Italian, owned by Magneti Marelli
• Zenith UK, Also produced the Zenith-Stromberg Carburetors

AMAL is a British carburettor brand name. ... Magneti-Marelli is an Italian company which designs and produces high-tech components and systems for the automotive industry. ... Honeywell Heating Specialties Company Stock Certificate dated 1924 signed by Mark C. Honeywell - courtesy of Scripophily. ... “Ford” redirects here. ... The Bendix Corporation was founded in 1924 by the inventor Vincent Bendix. ... The Chrysler Corporation was a United States-based automobile manufacturer that existed independently from 1925–1998. ... The school bus yellow paint was shining brightly on this new 1973 International Harvester - Wayne Lifeguard school bus won in a national contest for safety ideas. ... “Ford” redirects here. ... General Motors Corporation, also known as GM, an American multinational corporation, is the worlds largest auto company by production volume for the first 9 months of 2007, and by sales volume for 76 consecutive years. ... American Motors Corporation (AMC) was an American automobile company formed on January 14, 1954 by the merger of the Nash-Kelvinator Corporation and the Hudson Motor Car Company. ... Studebaker Corporation, or simply Studebaker, was a United States wagon and automobile manufacturer based in South Bend, Indiana. ... Mopeds are a class of low-powered motorized vehicles, generally two-wheeled. ... Briggs & Stratton is the worlds largest manufacturer of air-cooled gasoline engines for primarily outdoor power equipment. ... The Chrysler Corporation was a United States-based automobile manufacturer that existed independently from 1925–1998. ... The school bus yellow paint was shining brightly on this new 1973 International Harvester - Wayne Lifeguard school bus won in a national contest for safety ideas. ... “Ford” redirects here. ... General Motors Corporation, also known as GM, an American multinational corporation, is the worlds largest auto company by production volume for the first 9 months of 2007, and by sales volume for 76 consecutive years. ... American Motors Corporation (AMC) was an American automobile company formed on January 14, 1954 by the merger of the Nash-Kelvinator Corporation and the Hudson Motor Car Company. ... Studebaker Corporation, or simply Studebaker, was a United States wagon and automobile manufacturer based in South Bend, Indiana. ... It has been suggested that Hitachi Works be merged into this article or section. ... A keiretsu lit. ... This article is about the Japanese motor corporation. ... Volvo Cars is the luxury car maker using the Volvo Trademark. ... Volkswagen (VW) is an automobile manufacturer based in Wolfsburg, Germany. ... Audi AG is a German automobile manufacturer with headquarters in Ingolstadt, Bavaria, and has been an almost wholly owned (99. ... Rochester Products Division was a division of General Motors that manufactured carburetors, and related components including emissions control devices and cruise control systems. ... General Motors Corporation (NYSE: GM), also known as GM, is an American automobile maker with worldwide operations and brands including Buick, Cadillac, Chevrolet, GMC, Holden, Hummer, Opel, Pontiac, Saturn, Saab and Vauxhall. ... Solex was a French manufacturer of carburetors and powered bicycles. ... SU carburetteurs (named for Skinners Union, the company which produced them) were a brand of sidedraft carburetor widely used in British (Triumph, MG) and Swedish (Volvo, Saab 99) automobiles for much of the twentieth century. ... Tecumseh Products Company NASDAQ: TECUA NASDAQ: TECUB is a manufacturer of hermetic compressors for air conditioning and refrigeration products, gasoline engines and power train components for lawn and garden applications, industrial pumps, and small electric motors. ... Villiers is the name of several places, of families in France and the UK, and of products and companies: // Switzerland Villiers (NE), in the Val-de-Ruz district of the canton of Neuchâtel France Villiers is the name or part of the name of several communes in France: Villiers... Walbro Corporation A manufacturing company that specializes in small engine carburetion and supplier of auto parts. ... 1961 Ferrari 250TR Spyder engine fitted with 6 Weber 2 barrel downdraft carburetors Weber carburetors were originally produced in Italy by Edoardo Weber as part of a conversion kit for 1920s Fiats. ... Zenith Carburetters was a British company making carburetors. ...

External links

• The Fish carburetor
• Collection of photos and information concerning the Fish carburetor

Patents

• G.B. Рatent 11119 — Mixing chamber — Donát Bánki
• U.S. Patent 610,040  — Carburetor — Henry Ford
• U.S. Patent 1,750,354  — Carburetor — Charles Nelson Pogue
• U.S. Patent 1,938,497  — Carburetor — Charles Nelson Pogue
• U.S. Patent 1,997,497  — Carburetor — Charles Nelson Pogue
• U.S. Patent 2,026,798  — Carburetor — Charles Nelson Pogue
• U.S. Patent 2,982,528  — Vapor fuel system — Robert S. Shelton
• U.S. Patent 4,177,779  — Fuel economy system for an internal combustion engine — Thomas H. W.

Donát Bánki (1859-1922) was a Hungarian mechanical engineer, inventor of (among many other things) the carburetor. ... Henry Ford (1919) Henry Ford (July 30, 1863 – April 7, 1947) was the founder of the Ford Motor Company and father of modern assembly lines used in mass production. ...

References

1. ^ Encyclopedia of World Biography, 2005-2006, Thomson Gale
2. ^ http://www.andrew.cmu.edu/user/shimada/cad06/handouts/first-car.pdf Benz Patent
3. ^ RockAuto replacement parts catalogue
4. ^ Hibbard, Jeff (1983). Baja Bugs & Buggies. HP Books, p. 24. ISBN 0895861860. 
5. ^ http://www.aep.bigstep.com/Gcolortune.pdf