Carburetor

src: www.carburetor-parts.com

A carburetor (English American) or carburetor is a device that mixes air and fuel for internal combustion engines in the proper ratio for combustion. Sometimes this language is shortened to carbohydrates in the UK and North America or carby in Australia. For carburizing or carburet (and thus carburizing or carburizing , respectively) means mixing air and fuel or to equip (engine) with a carburetor for that purpose.

Most carburetors have been replaced in automotive and, to a lesser extent, the aviation industry with fuel injectors. They are still common on small machines for lawn mowers, rototillers and other equipment.

Video Carburetor

Etimologi

The word carburetor comes from the French carbure which means "carbide". Carburer means joining the carbon (compare also carburizing). In fuel chemistry, this term has a more specific meaning to increase the carbon content (and hence energy) of a fluid by mixing it with volatile hydrocarbons.

Maps Carburetor

History and development

The first carburetor was invented by Samuel Morey in 1826. Later, Enrico Bernardi developed another carburetor at the University of Padua in 1882, because his Motrice Pia, the first gasoline-burning engine (one cylinder, 121.6 cc) was made on 5 August 1882.

The carburetor was one of the earliest patents by Karl Benz (1888) when he developed the internal combustion engine and its components.

The initial carburetor is of a type of surface, where air is combined with fuel by passing the surface of the gasoline.

In 1885, Wilhelm Maybach and Gottlieb Daimler developed a floating carburettor based on the nozzle of the sprayer. The Daimler-Maybach carburetor is extensively copied, leading to patent lawsuits. The British court dismissed Daimler's priority corporate claims in favor of Edward Butler's 1884 spray carburetor used in its Petrol Cycle.

Hungarian engineers JÃÆ'¡nos Csonka and DonÃÆ'¡t BÃÆ'¡nki patented the carburetor for stationary machines in 1893.

Frederick William Lanchester from Birmingham, England, experimented with the carburetor axis in the car. In 1896, Frederick and his brother built the first gasoline-driven car in England, an internal combustion engine with 5 cylinder hp (3.7 kW) with chain propulsion. Unhappy with the performance and power of the car, they redesigned the engine the following year using two horizontally-resisted cylinders and the newly designed axis carburetor axis.

Carburetors were a common method of delivering fuel for most US-made gasoline engines until the late 1980s, when fuel injections became the preferred method. This change is dictated by the requirements of the catalytic converter and not due to inefficient carburizing inefficiency. The catalytic converter requires that there is more precise control over the fuel/air mixture to control the amount of oxygen remaining in the flue gas. In the US market, the last car using a carburetor is:

• 1990 (General) Ã,: Oldsmobile Custom Cruiser, Buick Estate Wagon, Cadillac Brougham, Honda Prelude (Basic Model), Subaru Justy
• 1991 (Police) Ã,: Ford Crown Victoria Police Interceptor with V8 engine 5.8Ã, L (351Ã, Â ° CuÃ,).
• 1991 (SUV) Ã:: Jeep Grand Wagoneer with AMC 360Ã machine, at (5.9Ã,L) V8.
• 1993 (Light Truck) Ã,: Mazda B2200
• 1994 (Light truck) Ã,: Isuzu

In Australia, several cars continued to use carburetors until the 1990s; These include Honda Civic (1993), Ford Laser (1994), Mazda 323 and Mitsubishi Magna sedans (1996), Daihatsu Charade (1997), and Suzuki Swift (1999). Inexpensive commercial Vans and 4WDs in Australia continued with carburetors even up to the 2000s, the last being the Mitsubishi Express van in 2003. Elsewhere, certain Lada cars used carburetors until 2006. Many motorcycles still use carburetors for simplicity, because the carburetor does not require the electrical system to function. Carburetors are also still found in small machines and in older or special cars, such as those designed for stock car racing, although the 2011 Nintore Sprint Cup season is the last with a carburetor engine; electronic fuel injection used starting with the 2012 racing season in the Cup.

In Europe, carburetor-engined cars were gradually wiped out in the late 1980s in favor of fuel injection, which is already an established type of engine in more expensive vehicles including luxury models and sports. The EEC Act requires all vehicles sold and produced in member states to have a catalytic converter after December 1992. This law has been on the pipeline for some time, with many cars becoming available with catalytic converters or fuel injectors from around 1990. However, some versions of the Peugeot 106 were sold with a carburetor engine from its launch in 1991, such as the Renault Clio and the Nissan Primera version (launched in 1990) and originally all Ford Fiesta versions, except the XR2i when it was launched in 1989. the Mercedes-Benz manufacturer has been producing mechanically engineered cars since the early 1950s, while the first major family car that featured fuel injection was the Volkswagen Golf GTI in 1976. Ford's first fuel injected car was the Ford Capri RS 2600 on 1970. General Motors launched its first fuel injection car on in 1957 as an option available to the first generation Corvette. Saab switched to fuel injections throughout its ranks from 1982.

src: images.holley.com

Principles

The carburetor works on the Bernoulli principle: faster air movement, lower static pressure, and higher dynamic pressure. The throttle relationship (accelerator) does not directly control the flow of liquid fuel. Instead, it drives a carburetor mechanism that measures the airflow brought into the engine. This flow velocity, and therefore pressure (static), determines the amount of fuel drawn into the airflow.

When a carburetor is used in a plane with a piston engine, special design and features are required to prevent fuel starvation during reverse flight. Then the engine uses the initial form of fuel injection known as carburetor pressure.

Most production carburetor engines, compared to fuel injectors, have a single carburetor and a suitable intake manifold that divides and transports the air/fuel mixture to the intake valve, although some engines (like motorcycle engines) use multiple carburetors on the split head. Some carburetor engines were also a general improvement to modify machines in the United States from the 1950s to the mid-1960s, and over the next decade high-performance cars, each carburetor gave a different room to the engine intake manifold.

The older machine uses an updraft carburetor, where air enters from under the carburetor and out through the top. It has the advantage of never flooding the machine, because every drop of liquid fuel will fall from the carburetor instead of to the intake manifold; it also lends itself to the use of oil bath air cleaner, where the oil pool under the mesh element under the carburetor is sucked into the mesh and the air is drawn through an oil-covered net; this is an effective system when the paper air filter does not exist.

Beginning in the late 1930s, downdraft carburettors were the most popular type for automotive use in the United States. In Europe, the sidedraft carburetor replaces downdraft due to the vacant space in the engine room and the use of the SU type carburettor (and similar units from other manufacturers) increases. Some small aircraft propeller engines still use updraft carburetor design.

The outboard motor carburetors are usually sidedraft, as they have to be stacked one on top of the other to feed the cylinder in a vertically oriented cylinder block.

The main disadvantage of basing a carburetor operation on the Bernoulli Principle is that, being a dynamic dynamic device, the reduction in pressure in the venturi tends to be proportional to the square of the air velocity of entry. The fuel jet is much smaller and the fuel flow is limited mainly by the viscosity of the fuel, so the fuel flow tends to be proportional to the pressure difference. So the full power-sized jets tend to starve the engine with low speed and partial throttle. Most commonly this has been fixed by using some jets. In SU and other variable jet carburetors, it is corrected by varying the jet size. To start cool, different principles are used in multi-jet carburetors. An airflow retaining valve called a choke, similar to a throttle valve, is placed in the main jet upstream to reduce intake manifold pressure and siphon additional fuel from the jet.

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Operation

Fixed-venturi

where the varying air velocities in the venturi control the flow of fuel; This architecture is used in most carburetors found in cars.

Variables-venturi

where the opening of the fuel jet varies by slide (which simultaneously changes the airflow). In a "constant depression" carburetor, this is done by a vacuum operated piston connected to a tapered needle that glide inside a fuel jet. A simpler version exists, most commonly found on small motorcycles and dirt bikes, where slides and needles are directly controlled by the throttle position. The most common variable venturi (constant depression) type of carburetor is the SU sidedraft SU carburettor and similar models from Hitachi, Zenith-Stromberg and other makers. The UK location of the SU and Zenith-Stromberg companies helped the carburetor rise to dominance position in the UK car market, although the carburetor is also heavily used on Volvo and other non-English brands. Other similar designs have been used in some European cars and some Japanese cars. This carburetor is also referred to as carburetor "constant speed" or "constant vacuum". An interesting variation is the Ford VV (venturi) carburetor, which is essentially a fixed venturi carburator with one side of a hinged venturi and moves to provide a narrow throat at lower rpm and a wider throat at high rpm. It was designed to provide good mixing and airflow at various engine speeds, although the VV carburetor proved problematic in service.

Under all operating conditions of the engine, the carburetor shall:

• Measure engine airflow
• Send the right amount of fuel to keep the fuel/air mixture in the right range (adjust by a factor like temperature)
• Mix them both smoothly and evenly

This work will be simple if air and gasoline (gasoline) are ideal fluids; in practice, however, their deviations from ideal behavior due to viscosity, fluid pull, inertia, etc. requires a lot of complexity to compensate for very high or low engine speeds. The carburetor should provide an appropriate fuel/air mixture at various ambient temperatures, atmospheric pressure, engine speed and load, and centrifugal force including the following scenarios;

• Cold start
• Starts hot
• Idling or slow running
• Acceleration
• High speed/high power at full speed
• Browse on throttle section (light load)

In addition, modern carburetors are required to do this while maintaining low exhaust emission levels.

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

Basics

The carburetor basically consists of an open pipe through which air enters the inlet cuff from the engine. The pipe is shaped venturi: narrowed in part and then widened again, causing increased airflow in speed at the narrowest. Under the venturi is a butterfly valve called a throttle valve - rotary disc that can be rotated to the end into the airflow, so that it hardly limits flow at all, or it can be rotated so that (almost) completely blocks airflow. This valve controls the flow of air through the carburetor's throat and thus the quantity of air/fuel mixture that the system will produce, thereby regulating power and engine speed. Throttle connected, usually through cable or mechanical connection of rods and joints or rarely by pneumatic links, to the accelerator on the car, throttle level on aircraft or equivalent control on vehicles or other equipment.

Fuel is fed into the airflow through small holes in the narrowest part of the venturi and in other places where the pressure will be lowered when not running at full speed. The fuel flow is adjusted by means of properly calibrated holes, referred to as jet , in the fuel path.

Off-idle Circuit

When the throttle valve is opened slightly from the fully closed position, the throttle plate reveals an additional fuel delivery hole behind the throttle plate where there is a low pressure area created by the throttle plate/Valve blocking the airflow; this allows more fuel to flow and compensates for the reduced vacuum that occurs when the throttle is opened, thus smoothing the transition to measured fuel flow through the regular open throttle circuit.

The main open-throttle circuit

As the throttle valve gets opened, the vacuum manifold decreases as there is little air flow restriction, reducing the flow of fuel through the idle and off-idle circuits. This is when the venturi form throat carburetors come into play, because of the Bernoulli principle (ie, when speed is increased, pressure drops). Venturi increases the air velocity, and this higher speed and thus lower pressure sucks the fuel into the airflow through the nozzle or nozzle located at the center of the venturi. Sometimes one or more additional venturisers are placed coaxially inside the primary venturi to increase the effect.

When the throttle valve is closed, the airflow through the venturi falls until the inherited pressure is insufficient to maintain the fuel flow, and the off-idle circuit takes over again, as described above.

The Bernoulli principle, which is a function of the fluid velocity, is the dominant effect for large openings and large flow rates, but because the flow of fluids on a small scale and low velocity (low Reynolds number) is dominated by viscosity, Bernoulli's principle is ineffective at idle or slow speeds and also in a very small carburetor of the smallest model engine. The small model engine has a flow restriction in front of the jet to reduce enough pressure to suck fuel into the airflow. Similarly, bursts and runs are slow pauses of large carburetors placed after the throttle valve where the pressure is partially reduced by a thick drag, not by the Bernoulli principle. The most commonly rich mixed-producer tool for powering cold machines is the choke, which works on the same principle.

Power valve

For open throttle operations, the richer fuel/air mixture will generate more power, prevent pre-ignition, and keep the engine cooler. This is usually overcome by a spring "spring valve", held closed by a vacuum machine. When the throttle valve opens, the vacuum manifold decreases and the spring opens the valve to allow more fuel into the main circuit. On a two-stroke engine, the operation of the power valve is the opposite of normal - usually "alive" and on a set of rpm it turns "off". It's activated at high rpm to extend the engine's spin range, utilizing a two-stroke tendency to turn higher momentarily when the mix is ​​slim.

As an alternative to using a power valve, the carburetor can use a meter jet or step step system to enrich fuel mixtures under high demand conditions. Such systems were originated by Carter Carburetors in the 1950s for the two main venturers of their four-barrel carburetor, and the widely used step-up rods on Carter 1 - 2, and 4-barrel carburettors during the end of production in the 1980s. The step-up rod is tapered at the lower end, which extends into the main metering jet. The top of the rod is connected to a vacuum piston or mechanical connection that lifts the rod out of the main jet when the throttle is opened (mechanical connection) or when the vacuum manifold (vacuum piston). When the step-up rod is lowered to the main jet, it limits the fuel flow. When the lifter rod is raised out of the jet, more fuel can flow through it. In this way, the amount of fuel delivered is adjusted to the demands of the transient engine. Some 4-barrel carburettors use measuring rods only on two main venturis, but some use them on primary and secondary circuits, such as the Rochester Quadrajet.

Accelerator pump

Liquid gas, which is denser than air, slower than air to react to the force applied to it. When the throttle opens quickly, the airflow through the carburetor increases rapidly, faster than the fuel flow rate may increase. This temporary surplus air supply causes a slender mix, which makes the engine misfire (or "tripping") - an effect that is opposite to what is required by opening the throttle. This is fixed by the use of a small piston or diaphragm pump which, when driven by a throttle relationship, forces a small amount of gasoline through the jet to the carburetor's throat. This extra fuel shot against transient lean conditions at the throttle end. Most accelerator pumps can be adjusted for volume or duration in several ways. Finally, the seal around the moving part of the pump will pump the reduced pump output; This shrinkage of the accelerator pump shakes down under acceleration until the seal on the pump is updated.

The accelerator pump can also be used to prime the engine with fuel before cold start. Excessive service, such as a choke that is not set correctly, can cause flood . This happens when too much fuel and insufficient air is present to support combustion. For this reason, most carburetors are equipped with an unloader mechanism: the accelerator is held on the throttle wide open when the engine is turned on, the unloader holds the open choke and recognizes extra air, and finally the excess fuel is cleared and the engine starts.

Choke

When the engine is cold, the fuel evaporates more easily and tends to condense on the intake manifold wall, exposing the fuel cylinder and making the engine difficult to start; thus, the richer mixture (more fuel into the air) is needed to start and run the engine until it heats up. The richer mix is ​​also more easily lit.

To provide extra fuel, choke is usually used; this is a device that limits the airflow at the entrance of the carburetor, before venturi. With this restriction in place, an extra vacuum is developed in the barrel carburetor, which attracts extra fuel through the main metering system to supplement the fuel withdrawn from the idle and off-idle circuits. It provides the rich mixture needed to maintain operation at low engine temperatures.

In addition, the choke can be connected to a cam ( fast idle cam ) or other device that prevents the throttle plate closing completely when the choke is in operation. This causes the machine to idle at higher speeds. Idle quickly serves as a way to help the engine warm up quickly, and provide a more stable idle by increasing airflow throughout the intake system which helps to better spray cold fuel.

In older carburettors, the choke is manually controlled by a Bowden cable and a pull knob on the dashboard. For easier, more comfortable, automatic choke driving; first introduced in 1932 Oldsmobile, became popular in the late 1950s. It is controlled by a thermostat that uses a bimetallic spring. When it is cold, the spring will contract, closing the choke plate. After startup, the spring will be heated by engine coolant, heat exhaust or electric heating coil. When heated, the spring will slowly expand and open the choke plate. A choke unloader is a relationship arrangement that forces the choke to open against its spring when the vehicle accelerator is moved to the end of its journey. This provision allows the machine to be "flooded" for cleaning so it will start.

Forgot to turn off the choke after the engine reaches its operating temperature will dispose of fuel and increase emissions. To meet the increasingly stringent emission requirements, some cars that still maintain manual chokes (circa 1980, depending on the market) begin to have an opening that is automatically controlled by a thermostat that uses bimetal springs, heated by engine coolant.

'Choke' for a constant-depressed carburetor such as SU or Stromberg does not use choke valves in air circuits but has mixed enrichment circuits to increase fuel flow by opening further metering jets or by opening additional fuel jets for 'enrichment'. Usually used on small engines, especially motorcycles, enrichment works by opening a secondary fuel circuit under the throttle valve. This circuit works exactly like an idle circuit, and when involved it only supplies extra fuel when the throttle is closed.

The classic British motorcycle, with a slide-throttle side-draft sidewalk, uses another type of "cold start device", called "tickler". This is just a spring shaft that, when depressed, manually pushes the float down and allows the excess fuel to fill the floating bowl and flood the intake ducts. If the "tickler" is held too long it also floods the exterior of the carburettor and crankcase below, and therefore the fire hazard.

Other elements

The interactions between each circuit can also be affected by various mechanical or air pressure connections as well as by components that are temperature sensitive and electric. It was introduced for reasons such as engine response, fuel efficiency or car emissions control. Various airflows (often chosen from a precisely calibrated distance, similar to a jet) allow air to be various parts of the fuel section to increase fuel delivery and evaporation. Additional enhancements may be included in carburetor/manifold combinations, such as some form of heating to aid fuel evaporation such as an initial fuel evaporator.

src: img.jpcycles.com

Fuel supply

Float chamber

To make sure the mixture is ready, the carburetor has a "float chamber" (or "bowl") that contains a certain amount of fuel at near-atmospheric pressure, ready for use. This reservoir continues to be replenished with fuel supplied by the fuel pump. The correct fuel level in the bowl is maintained by a buoy that controls the inlet valve, in a manner very similar to that used in a tank (eg a toilet tank). When the fuel runs out, float drop, open the inlet valve and receive fuel. When the fuel level rises, float up and close the inlet valve. The fuel levels maintained in a float bowl can usually be adjusted, whether by a setcrew or by something raw like bending a floating arm connected. This is usually a critical adjustment, and an appropriate adjustment is shown by lines emblazoned to the window in the float bowl, or the measurement of how far the float hangs below the top of the carburetor when it is dismantled, or similar. Floats can be made of different materials, such as brass sheets that are soldered into hollow shapes, or from plastics; hollow buoys can cause small leaks and plastic buoys can eventually become porous and lose flotation; in both cases the float will fail to float, the fuel level will be too high, and the machine will not run unless the float is replaced. The valve itself becomes obsolete on its sides by its movement in the "chair" and will eventually try to close at an angle, and thus fail to completely turn off the fuel; again, this will lead to excessive fuel flow and poor machine operation. Conversely, when the fuel evaporates from a floating bowl, it leaves behind sediment, residue, and varnish behind, which clogs the ducts and may interfere with buoy operations. This is especially a problem in cars that are operated only for a portion of the year and left standing with full buoy booths for months at a time; commercial fuel stabilizer additives are available that mitigate this problem.

Fuel stored in the chamber (bowl) can be a problem in hot climates. If the engine is turned off during heat, the fuel temperature will increase, sometimes boiling ("percolation"). This can cause flooding and restarting which is difficult or impossible when the machine is still warm, a phenomenon known as "hot soak". Heat deflectors and isolation gaskets seek to minimize this effect. Carburetor Carter Thermo-Quad has a floating space produced from insulating plastic (phenolic), which is said to keep the fuel 20 degrees Fahrenheit (11 degrees Celsius) cooler.

Typically, a special ventilation tube allows atmospheric pressure to be maintained in the floating space when the fuel level changes; This tube usually extends into the carburetor's throat. The placement of these ventilation tubes is essential to prevent fuel from sloshing out of them into the carburetor, and sometimes they are modified with longer tubes. Note that this leaves the fuel at atmospheric pressure, and therefore can not travel to the throat that has been pressed by a supercharger mounted upstream; in such cases, the entire carburetor shall be contained in an airtight pressurized box for operation. This is not required in installations where carburetors are installed in the upstream supercharger, which is for this reason the more frequent the system. However, this produces a supercharger filled with a mixture of fuel/compressed air, with a strong tendency to explode if the engine backfires; this type of explosion is often seen in a drag race, which for security reasons now incorporates a pressure blow-off plate on the intake manifold, a dotted bolt that holds the supercharger to the manifold, and a ballistic shrapnel blanket made of nylon or kevlar that surrounds it. supercharger.

Diaphragm space

If the machine must be operated in any orientation (eg chain saw or model plane), the buoy space does not match. Instead, the diaphragm space is used. The flexible diaphragm forms one side of the fuel chamber and is arranged in such a way that when the fuel is pulled out to the engine, the diaphragm is forced intoward by ambient air pressure. The diaphragm is connected to the needle valve and when it moves inward, the needle valve opens to receive more fuel, thus refilling the fuel when consumed. When the fuel is recharged, the diaphragm will move out due to fuel and spring pressure, closing the needle valve. A balanced state is achieved that creates a stable level of fuel reservoir, which remains constant in any orientation.

src: www.sudco.com

Some carburetor barrel

While the basic carburetor has only one venturi, many carburetors have more than one venturi, or "barrel". The two barrel and four barrel configurations are usually used to accommodate higher airflow rates with large engine displacements. Multi-barrel carburetors can have non-identical primary and secondary tunings of various sizes and are calibrated to provide different air/fuel mixtures; they can be moved by the relationship or by vacuum machine in "progressive" mode, so the secondary barrel does not start open until the introduction is almost completely open. This is a desirable characteristic that maximizes airflow through the main barrel (s) at most engine speeds, thereby maximizing the "signal" pressure of the venturis, but reducing the airflow restriction at high speed by adding a cross-sectional area for larger airflows. This advantage may be unimportant in high-performance applications where throttle operations are partially irrelevant, and primary and secondary are all open at once, for simplicity and reliability; also, the V-configuration engine, with two cylinder banks fed by a single carburetor, can be configured with two identical barrels, each supplying one bank of cylinders. In the widely visible combination of V8 and 4-barrel carburetors, there are often two primary barrels and two secondary barrels.

The first four barrel carburettors, with two main holes and two secondary holes, are identical Carter WCFB and Rochester 4GC simultaneously introduced in Cadillac 1952, Oldsmobile 98, Oldsmobile Super 88, and Buick Roadmaster. Oldsmobile refers to a new carburetor as "Quadri-Jet" (the original spelling) while Buick calls it "Air Power".

The four-barrel boring carburettor, was first released by Rochester in 1965 the year model as "Quadrajet" has a much larger spread between the primary and secondary sizes of throttle openings. Primers in such carburetors are relatively small compared to the conventional four-barrel exercise, while the latter is quite large. The small introduction helps fuel economy at low speed and driveability, while the big secondary allows maximum performance when called. To adjust the airflow through the secondary venturis, each of the secondary throats has an air valve at the top. It's configured like a choke plate, and lightly springs to a closed position. The open air valve is progressive in response to engine speed and throttle opening, gradually allowing more air to flow through the secondary side of the carburetor. Typically, the air valve is connected to a raised metering rod when the air valve is open, thus adjusting the secondary fuel stream.

Some carburettors can be mounted on one machine, often with progressive connections; two four-barrel carburetors (often referred to as "dual-quads") are often seen in high-performance American V8, and some two-barrel carburetors are often now seen on very high performing machines. A large number of small carburetors have also been used (see photo), although this configuration may restrict maximum airflow through the engine due to lack of public meeting space; with individual intake channels, not all cylinders draw air at once as the engine's crankshaft rotates.

src: www.dougrussell.com

Carburetor settings

Mixed fuels and air are too rich when they have excess fuel, and are too lean when not enough. This mixture is adapted to one or more needle valves on an automotive carburetor, or a pilot-operated lever on a piston engined aircraft (since the mixture changes with air density and therefore altitude). Independent of air density (stoichiatric) air to gasoline ratio is 14.7: 1, which means that for every unit of gasoline mass, it takes 14.7 air masses. There are different stoichiometric ratios for other types of fuels.

The way to check for the adjustment of the carburetor mixture includes: measuring the carbon monoxide, hydrocarbon, and oxygen content of the exhaust using a gas analyzer, or directly viewing the flame colors in the combustion chamber through a special ink-glass plug that is sold under the name "Colortune"; the stoichiometric flame burning color described as "Bunsen blue", turns yellow if the mixture is rich and whitish blue if too slim. Another method, widely used in aviation, is to measure the temperature of the exhaust gas, which is close to maximum for optimally adjusted mixture and decreases sharply when the mixture is too rich or too lean.

Mixtures can also be assessed by removing and examining spark plugs. Black, dry, and dirty plugs show an overly rich mixture; white or gray gray plugs show a sleek mix. The right mixture is shown by a brown/straw gray plug.

In a high-performance two-step engine, the fuel mixture can also be assessed by observing piston washing. Piston wash is the color and amount of carbon accumulation on the top (dome) piston. The slim engine will have a carbon black enclosed piston dome, and the richest engine will have a new-looking, clean piston dome free of carbon accumulation. This is often the opposite of intuition. Generally, the ideal mix will be between the two, with a clean dome area near the transfer port but some carbon in the center of the dome.

When setting two-stroke It is important to operate the engine at the most frequently operated rpm and throttle inputs. This will usually open wide or close to the throttle wide open. Low and idle RPMs can operate rich/slender readings and wobble, due to carburetor design to operate well at high air velocity through venturi and sacrifice low air speed performance.

Where some carburetors used their throttle mechanical connections must be properly synchronized for smooth running engine and a consistent fuel/air mixture for each cylinder.

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Feedback carburetor

In the 1980s, many American market vehicles use "feedback" carburettors that dynamically adjust fuel/air mixtures in response to signals from exhaust gas oxygen sensors to provide stoichiometric ratios to enable optimal functioning of catalytic converters. Carburetor feedback is mainly used because they are cheaper than fuel injection systems; they work well enough to meet emissions requirements in 1980 and are based on the existing carburetor design. Frequently, carburetor feedback is used in lower trim versions of a car (while higher specification versions are equipped with fuel injectors). However, their complexity compared to non-feedback carburettors and fuel injection makes them problematic and difficult to repair. Finally the collapse in hardware prices and more stringent emission standards led to fuel injection to replace the carburetor in the production of new vehicles.

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Catalytic carburetor

The catalytic carburetor mixes the fuel vapor with water and air in the presence of a heated catalyst such as nickel or platinum. This is commonly reported as a 1940s era product that would allow kerosene to power a gasoline engine (requiring lighter hydrocarbons). But reports are inconsistent; generally they are included in the description "carburetor 200 MPG" intended for the use of gasoline. There seems to be confusion with some of the older types of fuel steam carburetors (see vaporizor below). There are also very rarely useful references to real-world devices. Poorly referenced material on this topic should be viewed with suspicion.

src: carfromjapan.com

Constant vacuum carburetor

A constant vacuum carburetor, also called a variable choke carburetor and a constant speed carburetor, is a carburetor where the throttle cable connects directly to the throttle cable plate. Pulling the umbilical cord causes the raw gasoline to enter the carburetor, creating massive emissions of hyrdocarbons.

The Constant Velocity carburetor has variable throttle closure in the intake airflow before the gas pedal is operated throttle plate. Closure of this variable is controlled by intake manifold pressure/vacuum. This throttle-controlled pressure provides relatively uniform intake pressure across engine speed and load ranges. The most common CV carburetor designs are from SU or Solex, among others, using a cylinder closure operated by a diaphram. Cylinders and diaphrams are connected together with fuel gauge rods to provide fuel directly related to airflow. To provide a smoother operation and more intake pressure, the diaphram becomes thickened moisture. This carburetor enables excellent mobility and fuel efficiency. They can also be widely customized for best performance and efficiency. (See variable venturi carburetor above)

The CV carburetor's disadvantages include that it is limited to one barrel, side by side design. It is limited in use for most inline engines and also makes it impractical for large displacement machines. The throttle linkage required to install 2 or more CV carbides on the engine is complex and proper adjustment is essential for air/fuel distribution. This makes maintenance and adjustment difficult.

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Vaporizers

Internal combustion engines can be configured to run on different types of fuel, including gasoline, kerosene, tractor oil evaporation (TVO), vegetable oil, diesel fuel, biodiesel, ethanol fuel (alcohol), and others. Multifuel engines, such as gasoline-paraffin engines, can benefit from early fuel evaporation when they run more unstable fuel. For this purpose, vaporizer (or vaporiser ) is placed in the intake system. The vaporizer uses heat from the exhaust manifold to evaporate the fuel. For example, the original Fordson tractor and the subsequent Fordson models had a vaporizer. When Henry Ford & amp; Son Inc. designed the original Fordson (1916), a vaporizer used to provide kerosene operations. When TVO became common in many countries (including Britain and Australia) in the 1940s and 1950s, standard Ford evaporators on the Fordson model were equally useful for TVO. The widespread adoption of diesel engines in tractors makes the use of evaporative tractors of obsolete oil.

src: shop.pitsterpro.com

List of manufacturers

• AMAL, a carburetor and hand control manufacturer for British motorcycles and light industrial machines
• Autolite, a division of Ford Motor Company from 1967 to 1973
• Bendix Stromberg and bendix Technico carburetors are used on aircraft and vehicles made by Chrysler, IHC, Ford, GM, AMC, and Studebaker
• Carter, used in many vehicle brands, including those made by Chrysler, IHC, Ford, GM, AMC, and Studebaker, as well as on industrial and agricultural equipment and small machines.
• Claudel-Hobson, England
• Italian carbox of Dell'Orto, used on cars and motorcycles
• Edelbrock performance carburetor
• Hitachi, found in Japanese vehicles
• Holley, with the use of Carter and Weber
• Keihin, the Honda-affiliated keiretsu group company
• Mikuni, common on Japanese motorcycles, especially in the 1980s. Mikuni also makes racing carburettors for Japanese, British and European cars. Original equipment on Mitsubishi machine
• Reece Fish, in Volkswagen, Austin Mini, Morris Mini
• Rochester Products Division, a subsidiary of General Motors; also sell Weber/Magneti Marelli carburetor under license)
• Solex - French carburetor, owned by Weber
• SU Carburetors, widely used in British Commonwealth vehicles and European designs
• Villiers, used on British motorcycles and small engines
• Walbro and Tillotson carburetors for small engines
• Weber carburetor, Italy, now made in Spain, is owned by Magneti Marelli
• Zenith, used on Austin cars. Also produces a Zenith-Stromberg carburetor .

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See also

• Humidifier

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References

Further reading

General information

• Packer, Ed (July 1953). "Know your carburetor - what it is, what it does". Popular Mechanics . 100 (1): 181-184.
• American Technical Society. (1921). Engineering car; A work of general reference. Chicago: The American technical community.
• Lind, W. L. (1920). Internal combustion engine; Principles and their applications for cars, planes, and sea destinations. Boston: Ginn.
• Hutton, F. R. (1908). Gas engine. Minutes on internal combustion engines that use gas, gasoline, kerosene, alcohol, or other hydrocarbons as energy sources. New York: Wiley.

Patent

• AS. Patent 610.040 - Carburetor - Henry Ford

* [//www.google.com/patents/US1204901 Paten AS 1.204,901 Karburator Antoine Prosper Plaut]

• AS. Paten 1.750.354 - Karburator - Charles Nelson Pogue
• AS. Paten 1,938,497 - Karburator - Charles Nelson Pogue
• AS. Paten 1.997.497 - Karburator - Charles Nelson Pogue
• AS. Paten 2.026.798 - Karburator - Charles Nelson Pogue
• AS. Paten 2,214,273 - Karburator - J. R. Fish
• AS. Paten 2,982,528 - Sistem bahan bakar uap - Robert S. Shelton
• AS. Paten 4,177,779 - Sistem ekonomi bahan bakar untuk mesin pembakaran internal - Thomas H. W.
• G.B. ? atent 11119 - Ruang pencampuran - DonÃÆ'¡t BÃÆ'¡nki

Source of the article : Wikipedia