Talk:Carburetor

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barrel => brl ?

Not sure if this really belongs here, or maybe I'm the only one not knowing this - but if my guess is correct that "brl" is a common abbreviation for "barrel", perhaps this should be mentioned somewhere. I've often seen words like "4-brl carb" without ever knowing what "brl" means...--Cyberman TM (talk) 10:04, 25 March 2009 (UTC)

That is in fact incorrect. The abbreviation for "barrel" is "bbl", as in 1-bbl carburetor". Things like "brl" are leftovers from pay-by-the-letter classified ads, and do not belong in this article. —Scheinwerfermann ^T·_C17:02, 25 March 2009 (UTC)

Hard to understand

This article is really hard to understand. It seems to start with the assumption of a basic knowledge of how carburetors work and plunges into discussion of the various kinds etc. I know it's difficult to keep the right balance between technical accuracy and accessibility, but this piece copuld do with a much easier lead in to the details.93.97.194.138 (talk) 05:37, 19 June 2009 (UTC)

Wrong/misleading information

This article says that the carburetor was invented by Benz, and improved by Bánki-Csonka. Even the source indicated says that they were totally independent inventions, and Bánki-Csonka were first by 6 months.

Sudyke (talk) 13:36, 11 August 2009 (UTC) sudyke

Electronic carburetors

I propose to move this paragraph under a new heading:

"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." Aldo L (talk) 18:12, 16 January 2010 (UTC)

SV1 carburetor - should be added to the article

The SV1 Carburetor was invented and went into production in 2009 and patents are pending. This new carburetor has won many awards in the racing industry in it's debut year. It deserves a place in the carburetor section. It is a carburetor that has redefined and simplified the way carburetion works. See link www.sv1carb.com, Here is some discussion: http://www.speedtalk.com/forum/viewtopic.php?t=18793&sid=183b0f6a56466a27f2cfd6be809b3ab3 —Preceding unsigned comment added by Ljsystem12 (talk • contribs) 14:08, 22 October 2010 (UTC)

No, it has not "redefined the way carburetion works". Carburetion is the mixing of liquid fuel with air for combustion in an engine. The SV1 has not changed that definition. It's a different style of carburetor, that's all, and unless some reliable support can be found for the notion that it's anything more than that, including it as such would run afoul of the fact that Wikipedia is not an appropriate place to advertise products. —Scheinwerfermann ^T·_C22:31, 24 October 2010 (UTC)

The point of this wikipedia section is to make folks aware of the many types of different carburetor designs that have been manufactured in the history of carburetion. It also shows the many different ways in which fuel can be atomized and delivered to the engine. If you are concerned with the fact it is not a departure from current designs, allow me to make you more intimate with the design to improve your understanding. To prove this design is not only different it is better, be aware it won 8 World and National Records and won 6 Championships in its debut year of 2010 (you can delete this data from the facts page). However, no new carburetor design has done that in 40 years since the invention of the Holley Dominator series carburetor. The SV1 was entered against those older four barrel designs and proved itself to be superior to those modes of fuel and air mixing concepts in highly competitive class racing competition. The design is a departure from current modes of thinking in carburetor design. Patent pending atomization bars are the first of its kind that employ shear edges that are located at the venturi centerline (this keeps the fuel from having to be lifted above centerline and dropped back down, like four barrel carbs employ, so the SV1 design is faster to respond to fuel demand changes). The atomization bars more finely atomize the fuel with double the surface area of a conventional booster design and have more even fuel distribution. This is all racetrack and dyno proven data. This booster design also allows the engine to operate typically .5 of a ratio leaner for maximum power as compared to what a four barrel booster design can typically achieve. This improved efficency not only produces power BUT the new style is more responsive to throttle movement as well as it works from the edge of the venturi to the middle. Four barrel designs in comparison require the blade to be fully open before the booster can see maximum signal. The SV1 design allows the booster to see signal from the moment the blade begins to open. This dramatically improves throttle response. Also on four barrel carbs the throttle blade blocks the center of the booster. This delays and hurts signal change response time. On the SV1, signal is generated on both sides of the booster, the blade does not block the signal generation area of the booster, so response time is drastically improved in comparison. Also the design is the first single blade carburetor that feeds idle fuel to the whole perimeter of the blade (360 degrees). This allows for an amazing idle quality that a four barrel carburetor cannot match as no "clean air" is allowed into the engine. On previous single blade carbs and all four barrel carbs, the front of the blade mixes fuel and air, the rear of the blade only allows in air. As a result we have always thought that most high performance engines cannot idle cleanly below the 1100-1200 rpm range. The SV1 design disproved that, with a single blade perimeter transfer and idle feed design (also Patent Pending) that allows a clean 700-800 rpm idle on the same engine design. The design was such a move forward in carburetion that it was immediately BANNED by the SCCA as an unfair advantage and other organizations like the NMCA, NMRA and NHRA followed suit. Those that did not ban the design altogether, required weight and cfm restrictions to allow the four barrel designs to be competitive against the SV1. —Preceding unsigned comment added by 72.184.130.102 (talk) 13:45, 24 January 2011 (UTC)

Sounds like a nifty carburetor. Wikipedia is still not an advertising venue. —Scheinwerfermann ^T·_C23:01, 24 January 2011 (UTC)

Do we need a stub for this "nifty" classification?

Wikipedia suffers greatly from the fact that every article has one overseer and he/she rules. They sorely need a way to include various views but they do not have it. The above comment is a good illustration of an important feature that will go unmentioned. Arydberg (talk) 18:12, 5 July 2011 (UTC)

Your perception of Wikipedia "suffering greatly" in fact appears to be nothing more or less than your unwillingness or inability to understand how this project works. —Scheinwerfermann ^T·_C20:59, 5 July 2011 (UTC)

Accelerator pump function

It has been my understanding that an accelerator pump or similar function is needed because a richer mixture is needed for combustion at wider throttle but the intake manifold has lean mixture in it. This might be compensated by higher temperature in steady state, but not as the throttle first opens. The article now says that the pump is needed because of the inertia of the fuel. This makes some sense, because the force on the fuel does not increase until the air is already moving faster. However, my feeling for the magnitudes is that the fuel's inertia is not significant. I have not put in numbers, so I am not sure of this, so I am not now making that change now. David R. Ingham (talk) 05:02, 4 December 2010 (UTC)

The "inertia of the fuel" explanation is correct; your understanding is not. —Scheinwerfermann ^T·_C00:01, 6 December 2010 (UTC)

The statement Liquid gasoline is heavier than air, and so has greater inertia is nonsense. Inertia is a property displayed equally by all bodies. It is incorrect to imagine an elephant has more inertia than a mosquito. Inertia states Inertia is represented numerically by an object’s mass. An elephant has more mass than a mosquito, but they both display the property of inertia equally. It would be reasonable to write Liquid gasoline is denser than air, and so has greater mass but that would be a statement of the obvious.

David R. Ingham has written a richer mixture is needed for combustion at wider throttle. That is not correct. An air-fuel ratio that is suitable for operation of the engine is equally suitable at all throttle positions. The role of the carburettor is to supply a mixture of almost constant air-fuel ratio regardless of the throttle position.

The statement When the throttle is rapidly opened, airflow through the carburettor therefore increases faster than the fuel flow rate can increase is also incorrect. Fuel is drawn into the throat of the carburettor because of the difference in pressure between the fuel bowl and the carburettor venturi. If the airflow increases (or decreases) the pressure in the venturi decreases (or increases) in proportion. There is no lag in the change in pressure. The rate at which fuel enters the throat changes in proportion to the change in pressure difference, and there is no lag due to inertia or any other reason.

Here is my explanation of the role of the accelerator pump.

• Carburettors are adjusted to deliver a mixture that is close to the air-fuel ratio for best economy. This is significantly leaner than the ratio for best power. When the driver calls for a rapid increase in engine speed by rapidly opening the throttle this can be achieved quickest if a richer mixture, close to the ratio for best power, is supplied by the carburettor. An accelerator pump briefly delivers extra fuel to enrich the mixture suitable for best power.
• Fuel enters the throat as atomised droplets. As the charge flows towards the cylinders the droplets vapourise to a large extent. At low manifold pressures (eg idle throttle position) the low pressure aids in vaporisation of the droplets. At high manifold pressures (eg high power) the higher pressure retards vapourisation of the droplets and the interior of the throat and inlet manifold is wet with liquid fuel. When the throttle is opened quickly there is a quick rise in manifold pressure which causes an increase in the amount of liquid fuel wetting the interior of the throat and inlet manifold. As a result of a net increase in the amount of liquid fuel wetting the interior there would be an increase in the air-fuel ratio (leaner mixture) of the charge reaching the cylinders. So when the driver calls for an increase in engine speed or power the result would be a leaner mixture that delays the increase. This can be avoided by use of an accelerator pump. When the throttle is opened quickly the pump injects extra fuel into the throat so the mixture in the throat is enriched. However, by the time this charge reaches the cylinders a little of the fuel has been lost to the walls of the throat and inlet manifold so the air-fuel ratio has fallen to approximately the best value for accelerating the engine.

When the throttle is closed quickly there is a rapid reduction in manifold pressure and a net reduction in the amount of fuel wetting the walls of the throat and inlet manifold. This delivers an extra-rich mixture to the cylinders. The extra-rich mixture isn’t a problem when the throttle is being closed because the driver is calling for a reduction in engine speed or power. Dolphin (t) 02:38, 6 December 2010 (UTC)

Mm. What you are calling "nonsense" is readily demonstrable with simple equipment. Try it a few times for yourself if you're unsure. You appear to be quibbling over terminology, and you may have a legitimate beef—it hinges on how accessible we want to make this article to a naïve (per se) readership. Please propose phrasing that will, without transgressing your comfort zone surrounding the use of the word inertia, describe the reality that air reacts faster than fuel to the rapidly opened throttle, which causes a transient lean condition remedied by an accelerator pump. Yes, the sudden increase in manifold pressure does tend to cause a wet manifold, particularly when the manifold is cold. However, this is neither the only nor the primary reason why an accelerator pump is needed, as you can easily demonstrate to yourself by disabling the accelerator pump on a carburetor atop an engine warmed to full operating temperature and then flooring the accelerator. Yes, the misfire "stumble" will be less pronounced than with a cold engine (which will often stall altogether) but it will still be present.

Moreover, while you're correct about the mechanism behind the spike in mixture strength resulting from sudden throttle closure (i.e., sudden drop in manifold pressure), you're quite incorrect that this "isn't a problem"; it is in fact an enormous problem from the standpoint of exhaust emissions toxicity. Slow-closing throttle dashpots and throttle position solenoids were amongst the first emission control devices applied to carbureted cars in the late 1960s (and before that, dashpots were common on vehicles with manual transmissions whereon the engine could stall on the overly-rich mixture if the driver declutched before the engine could be back-driven by the transmission to exhaust the overly-rich mixture). —Scheinwerfermann ^T·_C03:34, 6 December 2010 (UTC)

I concede that I am quibbling over terminology, but that is because we are writing an encyclopedia.

Having thought about it for a while I don't have an in-principle objection to use of the concept of inertia. For example, if we were describing the maldistribution of air-fuel ratio of the charge delivered to each cylinder in an engine that has more cylinders than carburetors I wouldn't object to the explanation that inertia causes the droplets of atomised fuel to follow paths that don't conform to the streamlines in the flow of vapour. However, I see no grounds for suggesting that inertia causes a momentarily lean mixture whenever the throttle is opened quickly. Imagine an engine operating steadily at low power and drawing one kilogram per minute from the carburetor. Now imagine the same engine operating steadily at high power and drawing ten kilograms per minute. The suggestion has been made that when this engine is at the low power setting and the throttle is opened briskly to the high power setting there is a delay as the fuel flow increases from one to ten kilograms per minute due to inertia of the fuel. I ask "What fuel suffers inertia effects as the result of having to accelerate?" If the contents of the carburetor bowl have to be accelerated from a low speed to a high speed I could see that there is inertia evident as the mass of the fuel in the bowl is accelerated, perhaps from speed V to speed 10xV. However, the content of the bowl is stationary at both high and low power settings. There is an almost-stationary pool of fuel upstream of the jet, and then over the short length of the jet a small amount of fluid is accelerating each second through the jet and atomising into droplets in the throat of the carburetor. At high power setting more fuel per second is accelerating through the jet than at low power setting, but there is no significant quantity of fuel that has a speed proportional to the power setting, and that needs to be accelerated when the throttle is opened briskly. In the absence of someone being able to identify an amount of fuel that has to be accelerated when going from a low power to a high power setting the suggestion that the momentarily lean mixture is somehow due to differential inertia of fuel and air isn't plausible. That is why I railed against the rather glib suggestion that it is due to the inertia of the fuel.

Thanks for the good information about toxicity of emissions and slow-closing throttle dashpots. My experience doesn't include such things but you have described them very well. Dolphin (t) 10:22, 6 December 2010 (UTC)

An interesting discussion, this, but we're not really getting anywhere. I'll add some reliable sources to the assertion regarding inertial delay of fuel upon rapid throttle opening. —Scheinwerfermann ^T·_C06:16, 7 December 2010 (UTC)

That will be good. The article is presently conspicuously lacking in-line citations. The sub-section on accelerator pump is yet to receive its first citation. Dolphin (t) 12:00, 7 December 2010 (UTC)

I am in complete agreement. Many automotive articles suffer from this malady, for there are a great many contributors with more enthusiasm than actual knowledge, and there's a great deal of folk "wisdom" for them to parrot. —Scheinwerfermann ^T·_C17:22, 7 December 2010 (UTC)

Accelerator pumps are also used to replenish the film of petrol that is deposited inside the inlet manifold. In constant speed running there is an equilibrium between fuel being deposited on the walls of the manifold and fuel evaporating. When the throttle is closed this evaporates in the near vacuum created, if the throttle is now opened the engine will run lean until the film of petrol is re-established. Constant vacuum carburettors such as the SU do not suffer from any of the effects discussed above, but still need an accelerator pump effect to replenish the film of petrol, this is usually done with a damper on the CV piston or with a true pump on some Ford types. DonSayers. — Preceding unsigned comment added by 86.164.78.8 (talk) 16:49, 17 November 2011 (UTC)

Is this notion you describe verifiable by reference to reliable sources? —Scheinwerfermann ^T·_C18:42, 17 November 2011 (UTC)

As many as you have provided sunshine. — Preceding unsigned comment added by Donsayers (talk • contribs) 20:04, 18 November 2011 (UTC)

H'm. Are you sure? I've provided a fair number of refs for existing text and a great deal of supported content in this article, but I'm not seeing any of either from you. Also, please remember to properly sign your posts on article talk pages, thanks. —Scheinwerfermann ^T·_C03:59, 19 November 2011 (UTC)

Catalytic carburetor

There may be such a thing as a catalytic carburetor but it is not the same thing as a carburetor used for tractor vaporizing oil (TVO). A TVO carburetor has no catalyst, it just uses heat from the exhaust to vaporize the non-volatile kerosene fuel. Biscuittin (talk) 13:50, 23 July 2011 (UTC)

I have corrected this by splitting the section. Biscuittin (talk) 14:25, 23 July 2011 (UTC)