A carburetor (North American spelling) or carburettor (Commonwealth spelling), is a device that blends air and fuel for an internal combustion engine. American and British English spelling differences are one aspect of American and British English differences. Temperature and layers The temperature of the Earth's atmosphere varies with altitude the mathematical relationship between temperature and altitude varies among five Fuel is any material that is burned or altered in order to obtain energy 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 It was invented by Karl Benz before 1885[1] and patented in 1886. Karl Friedrich Benz, sometimes spelled Carl, ( November 25, 1844, Karlsruhe, Germany – April 4, 1929, Ladenburg Year 1885 ( MDCCCLXXXV) was a Common year starting on Thursday (link will display the full calendar of the Gregorian calendar (or a Common Year 1886 ( MDCCCLXXXVI) was a Common year starting on Friday (link will display the full calendar of the Gregorian calendar (or a Common [2] It is colloquially called a carb (in North America and the United Kingdom) or carby (chiefly in Australia).
The word carburetor comes from the French carbure, meaning 'carbide' [1]. For the Software development tool targeting the Symbian OS, see Carbide To carburete means to combine with carbon. Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6 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. Carbon (kɑɹbən is a Chemical element with the symbol C and its Atomic number is 6 In Organic chemistry, a hydrocarbon is an Organic compound consisting entirely of Hydrogen and Carbon.
Contents |
History and development
The carburetor was invented by the Hungarian engineer Donát Bánki in 1893. Hungary (Magyarország 'mɔɟɔrorsaːg) officially in English the Republic of Hungary ( Magyar Köztársaság, literally Magyar (Hungarian Republic An engineer is a person professionally engaged in a field of Engineering. Donát Bánki ( June 6, 1859 - August 1, 1922)was a Hungarian mechanical Engineer, inventor of (among many other things Frederick William Lanchester of Birmingham, England experimented early on with the wick carburetor in cars. Frederick William Lanchester, Hon FRAeS ( October 23, 1868 - March 8, 1946) was an English Polymath and Birmingham ( ˈbɜːmɪŋəm Ber -ming-um 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.
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. Fuel injection is a system for mixing fuel with air in an Internal combustion engine. 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. The Crown Victoria Police Interceptor (often referred to simply as CVPI or P71) is the law enforcement version of the Ford Crown Victoria. The Windsor engine is a 90-degree Small-block V8 from Ford Motor Company. ( is a Japanese car commercial vehicle and heavy truck manufacturing company, headquartered in Tokyo. [3] Elsewhere, Lada cars used carburetors until 1996. Lada is the Trademark of AvtoVAZ, a Russian car manufacturer in Togliatti, ( Samara Oblast or province A majority of motorcycles still utilize carburetors due to lower cost and throttle response problems with early injection set ups, but as of 2005, many new models are now being introduced with fuel injection. MotorCycle is the title of a 1993 album by Rock band Daniel Amos, released on BAI Records. Year 2005 ( MMV) was a Common year starting on Saturday (link displays full calendar of the Gregorian calendar. Fuel injection is a system for mixing fuel with air in an Internal combustion engine. Carburetors are still found in small engines and in older or specialized automobiles, such as those designed for stock car racing. Stock car racing is a form of Automobile racing found mainly in the United States, Canada, New Zealand and Great Britain
Principles
The carburetor works on Bernoulli's principle: the faster air moves, the lower its static pressure, and the higher its dynamic pressure. In Fluid dynamics, Bernoulli's principle states that for an Inviscid flow, an increase in the speed of the fluid occurs simultaneously with a decrease in In the design and operation of Aircraft, static pressure is the air pressure in the aircraft’s static pressure system. In Fluid dynamics dynamic pressure (indicated with q, or Q, and sometimes called velocity pressure) is the quantity defined by The throttle (accelerator) linkage does not directly control the flow of liquid fuel. A throttle is the mechanism by which the flow of a fluid is managed by constriction or obstruction 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.
When carburetors are used in small aircraft with piston engines, special designs and features as found in e. 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 g. the Bendix carburetor are needed to avoid fuel starvation under high g-forces. The Bendix Corporation was an American manufacturing and engineering company which during various times in its 60 year existence made brake systems aeronautical hydraulics
Most carbureted (as opposed to fuel-injected) engines have a single carburetor, though some engines use multiple carburetors. Fuel injection is a system for mixing fuel with air in an Internal combustion engine. 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. 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 the part of an Engine that supplies the Fuel / Air mixture to Motor oil, or engine oil, is an Oil used for lubrication of various Internal combustion engines While the main function is to lubricate Moving An air filter is a device which removes solid Particulates such as Dust, Pollen, Mold, and bacteria from Air. An air filter is a device which removes solid Particulates such as Dust, Pollen, Mold, and bacteria from Air.
Beginning in the late 1930s, downdraft carburetors were the most popular type for automotive use in the United States. The United States of America —commonly referred to as the 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. SU carburettors (named for Skinners Union, the company that produced them were a brand of Carburettor usually of the sidedraught type but downdraught variants were 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.
Operation
- 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). The Venturi effect is the fluid pressure that results when an incompressible fluid flows through a constricted section of pipe 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. SU carburettors (named for Skinners Union, the company that produced them were a brand of Carburettor usually of the sidedraught type but downdraught variants were 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. This article is about Volvo Group - AB Volvo Volvo Cars is the passenger vehicle maker owned by Ford Motor Company, using the Volvo Trademark 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:
- 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:
- 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. Automobile emissions control covers all the technologies that are employed to reduce the Air pollution -causing emissions produced by Automobiles Exhaust emissions
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. In Automotive engineering, an intake manifold or inlet manifold is the part of an Engine that supplies the Fuel / Air mixture to 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. A butterfly valve is a type of flow control device typically used to regulate a fluid flowing through a section of pipe 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. For the character in the Thursday Next Series see Characters in the Thursday Next Series. The Hillman Imp is a compact rear-engined saloon car that was manufactured under the Hillman Marque by the Rootes Group (later Chrysler
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. A throttle is the mechanism by which the flow of a fluid is managed by constriction or obstruction This is where the venturi shape of the carburetor throat comes into play, due to Bernoulli's principle (i. The Venturi effect is the fluid pressure that results when an incompressible fluid flows through a constricted section of pipe In Fluid dynamics, Bernoulli's principle states that for an Inviscid flow, an increase in the speed of the fluid occurs simultaneously with a decrease in 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.
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. In Fluid mechanics and Heat transfer, the Reynolds number \mathrm{Re} is a Dimensionless number that gives a measure of the Ratio Viscosity is a measure of the resistance of a Fluid which is being deformed by either Shear stress or Extensional stress. 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.
Power valve
For open throttle operation a richer mixture will produce more power, prevent detonation, and keep the engine cooler. Knocking (also called knock, detonation or spark knock, pinking in UK English or pinging in US English in spark-ignition 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". The two-stroke Internal combustion engine differs from the more common Four-stroke engine by completing the same four processes (intake compression combustion exhaust 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.
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 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 at wide open throttle 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. A thermostat is a device for regulating the Temperature of a System so that the system's temperature is maintained near a desired setpoint Bi-metal refers to an object that is composed of two separate Metals joined together 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.
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. Fuel efficiency, in its basic sense is the same as Thermal efficiency, meaning the efficiency of a process that converts chemical potential energy contained in a carrier Automobile emissions control covers all the technologies that are employed to reduce the Air pollution -causing emissions produced by Automobiles Exhaust emissions 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. The Early fuel evaporator is a device found in some Internal combustion engines with Carburetors It can sometimes be referred to as an Electronic fuel evaporator
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. "Fuel pump" should not be confused with Fuel dispenser, a device that dispenses fuel into an automobile 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. For other uses see Valve (disambiguation. For the electronic component see Thermionic valve. A toilet is a Plumbing fixture and disposal system primarily intended for the disposal of the bodily wastes: Urine and fecal matter. 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. Brass is any Alloy of Copper and Zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties 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.
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. A supercharger is an air compressor used for Forced induction of an Internal combustion engine. 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. Drag racing is a competition in which objects compete to be the first to cross a set finish mark usually from a dead stop and in a straight line
If the engine must be operated in any orientation (for example a chain saw), a float chamber cannot work. A chainsaw (or chain saw) is a portable mechanical motorized Saw. 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. A needle valve is a type of valve having a small orifice and a threaded needle-like plunger 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.
Multiple carburetor barrels
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. Engine displacement is defined as the total Volume of air/fuel mixture an Engine can draw in during one complete engine cycle it is normally stated in Cubic 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.
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). A needle valve is a type of valve having a small orifice and a threaded needle-like plunger The density of a material is defined as its Mass per unit Volume: \rho = \frac{m}{V} Different materials usually have different The (stoichiometric) air to gasoline ratio is 14. Stoichiometry (sometimes called reaction stoichiometry to distinguish it from composition stoichiometry is the Calculation of Quantitative (measurable A ratio is an expression which compares quantities relative to each other 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.
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. Carbon monoxide, with the chemical formula CO is a colorless odorless tasteless yet highly toxic Gas. Oxygen (from the Greek roots ὀξύς (oxys (acid literally "sharp" from the taste of acids and -γενής (-genēs (producer literally begetteris the 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.
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. A spark plug (also very rarely nowadays in British English: a sparking plug) is an electrical device that fits into the Cylinder Black is the Color of objects that do not emit or Reflect Light in any part of the Visible spectrum; they absorb all such frequencies of Soot (ˈsʊt is a general term that refers to the black impure carbon particles resulting from the incomplete combustion of a hydrocarbon White is a Color, the perception which is evoked by Light that stimulates all three types of color sensitive Cone cells in the Human eye The correct color should be a brownish gray. Black, when used as a general term is a color that is a Very dark Black, black, or Black, of low Luminance relative to See also reading spark plugs. A spark plug (also very rarely nowadays in British English: a sparking plug) is an electrical device that fits into the Cylinder
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. An oxygen sensor, or lambda sensor is an electronic device that measures the proportion of Oxygen (O2 in the gas or liquid being analyzed 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. Fuel injection is a system for mixing fuel with air in 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. Catalysis is the process in which the rate of a Chemical reaction is increased by means of a Chemical substance known as a catalyst Nickel (ˈnɪkəl is a metallic Chemical element with the symbol Ni and Atomic number 28 Platinum (ˈplætɪnəm is a Chemical element with the Atomic symbol Pt and an Atomic number of 78 This breaks the fuel down into methane, alcohols, and other lighter-weight fuels. Methane is a Chemical compound with the molecular formula. It is the simplest Alkane, and the principal component of Natural gas. In Chemistry, an alcohol is any Organic compound in which a Hydroxyl group ( - O[[hydrogen H]]) is bound to a Carbon The original catalytic carburetor was introduced to permit farmers to run tractors from modified and enriched kerosene. Tractor vaporising oil (or TVO) is a fuel for Internal combustion engines produced from paraffin ( Kerosene) The U. S. Army also used catalytic carburetors with great success in World War II, in the North African desert campaign.
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. Tetra-ethyl lead, abbreviated TEL, is an organometallic compound with the formula ( CH3CH2)4 Pb. Knocking (also called knock, detonation or spark knock, pinking in UK English or pinging in US English in spark-ignition The compression ratio is a single number that can be used to predict the performance of any engine particularly piston engines (but can be used on essentially any Internal-combustion Second, the economic advantage of using kerosene over gasoline faded in the 1930s, eliminating the catalytic carburetor's primary advantage.
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. AMAL is a British Carburettor trademark AMAL were the suppliers of carburettors to the British motorcycle industry and their products were present on the products Magneti Marelli Holding SpA is an Italian company which deals with development and manufacturing of systems modules and high-technology components for the Automotive Honeywell ( is a major American multinational conglomerate company that produces a variety of consumer products engineering services and aerospace systems Ford Motor Company is an American Multinational corporation and the world's fourth largest automaker based on Worldwide vehicle sales, following
- 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. The Bendix Corporation was an American manufacturing and engineering company which during various times in its 60 year existence made brake systems aeronautical hydraulics Chrysler LLC is an American Automobile manufacturer that has been producing Automobiles since 1925 International Harvester Company ( IHC or IH; now Navistar International Corporation) was an agricultural machinery construction equipment Ford Motor Company is an American Multinational corporation and the world's fourth largest automaker based on Worldwide vehicle sales, following General Motors Corporation ( GM) ( is a multinational automobile manufacturer founded in 1908 and headquartered in the United States. American Motors Corporation (AMC was an American automobile company formed on January 14 1954 by the merger of the Nash-Kelvinator Corporation Studebaker Corporation, or simply Studebaker, was a United States Wagon and Automobile manufacturer based in Mopeds are a class of low-powered (typically under 50 cc displacement) motorized vehicle generally two or three wheeled Briggs & Stratton is one of the world's largest manufacturers of Air-cooled Gasoline engines for primarily outdoor power equipment 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. Chrysler LLC is an American Automobile manufacturer that has been producing Automobiles since 1925 International Harvester Company ( IHC or IH; now Navistar International Corporation) was an agricultural machinery construction equipment Ford Motor Company is an American Multinational corporation and the world's fourth largest automaker based on Worldwide vehicle sales, following General Motors Corporation ( GM) ( is a multinational automobile manufacturer founded in 1908 and headquartered in the United States. American Motors Corporation (AMC was an American automobile company formed on January 14 1954 by the merger of the Nash-Kelvinator Corporation Studebaker Corporation, or simply Studebaker, was a United States Wagon and Automobile manufacturer based in () is a Multinational corporation specializing in high-technology and services headquartered in Marunouchi Itchome Chiyoda, Tokyo, Japan.
- 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. A is a set of companies with interlocking Business relationships and shareholdings. () is a Multinational corporation, engine Manufacturer and engineering corporation headquartered in Japan. This article is about Volvo Group - AB Volvo Volvo Cars is the passenger vehicle maker owned by Ford Motor Company, using the Volvo Trademark AUDI AG, ( Xetra: NSU commonly known as Audi (aˈʊdi is a German Automobile manufacturer which produces Audi branded cars with headquarters Rochester Products Division was a division of General Motors that manufactured Carburetors, and related components including Emissions control devices General Motors Corporation ( GM) ( is a multinational automobile manufacturer founded in 1908 and headquartered in the United States. Solex was a French manufacturer of Carburetors and the powered bicycle VéloSoleX. SU carburettors (named for Skinners Union, the company that produced them were a brand of Carburettor usually of the sidedraught type but downdraught variants were Tecumseh Products Company is a manufacturer hermetic compressors for Air conditioning and refrigeration products 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
External links
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 2,214,273 — Carburetor — J. Villiers Engineering Ltd was a manufacturer of Motorcycles and cycle parts and an engineering company based in Villiers Street Wolverhampton In the 1890's Walbro Corporation is a manufacturing company that specializes in small engine carburetion and supplier of auto parts Weber is an a Italian company producing Carburetors currently owned by Magneti Marelli Powertrain S Zenith Carburetters was a British company making carburettors. Donát Bánki ( June 6, 1859 - August 1, 1922)was a Hungarian mechanical Engineer, inventor of (among many other things Henry Ford ( July 30, 1863 &ndash April 7, 1947) was the American founder of the Ford Motor Company and father of R. Fish
- 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.
References
- ^ Encyclopedia of World Biography, 2005-2006, Thomson Gale
- ^ http://www.andrew.cmu.edu/user/shimada/cad06/handouts/first-car.pdf Benz Patent
- ^ RockAuto replacement parts catalogue
- ^ Hibbard, Jeff (1983). Baja Bugs & Buggies. HP Books, p. 24. ISBN 0895861860.
- ^ http://www.aep.bigstep.com/Gcolortune.pdf
Dictionary
carburetor
-noun
- (US) A device in an internal combustion engine where fuel is vapourized and mixed with air prior to ignition.
Dapyx Software network: MP3 Explorer | Ebook Manager | Zenithic