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what was the engineering rationale for the updraft design, such as the carter rjh-08?..and what technological innovations that allowed the downdraft to become the norm?..  epi
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The first carburetors were a pool of gas that air was passed over. Later wicks were added to increase the amount of gas that could be mixed with air. Then they figured out how to draw liquid gas up a small tube and then create turbulant flow to mix it with air. All those were with the gas pool below the air intake.
Around the late 20s they discovered a way to position the gas in the middle of the carburetor and use syphon and aspiration to feed the gas into the air flow. That produced the downdraft carburetors. Numerous refinements to reduce overfueling and underfueling in certain situations, (perculation, syphoning, boiling of the gas and ??? finally (after 50 years) produced a reliable fuel efficient gas/air mixing system [computer controlled fuel injection].
How Sweet the roar of a Chevy four!
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He!He!.... That Chipper fellow sounds like someone that was vaccinated with a phonograph needle! (I jest heard that expression again today after many years ) and I wanted to use it in a sentence.....
Life's a long winding trail, love Jesus and ride a good horse!
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chipper, right, but in the twenties, they must have thought somehow that updrafting was better than down?..why?.. epi
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I have read that the updraft carbs were used before technology got to the point that float bowl and needle and seats became reliable enough to prevent the raw gasoline from running down into the manifold and the cylinders at idle and after shutdown, makeing a severely flooded engine almost impossible to start and washing down the cylinders with raw gasoline and contaminate the oil sumpt some of the first efforts of useing downdraft carbs resulted in having the pan blown off!
I just got vaccinated with a phonograph needle like the one used on Chipper!
Life's a long winding trail, love Jesus and ride a good horse!
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macky, thanks...very interesting points... epi
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Tech Advisor ChatMaster - 25,000
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The Mangy Old Mutt
"If It's Not Junk.....It's Not Treasure!"
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Dosn't a gas ignite faster that a liquid?
Chat Group Chapter Member
Current rides;
1968 Camaro rs/SS 350 4spd
2000 Blazer LT
2005 Malibu Maxx
2007 Acura TDX
Last total restoration;
1932 Sport Coupe
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I am not aware of any liquid that will ignite. There might be one but if so it must be essentially fuel and oxidizer in one molecule. Even all those that I am aware of will only ignite in the gasseous form.
How Sweet the roar of a Chevy four!
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how about Hydrogen peroxide and LOX?
Life's a long winding trail, love Jesus and ride a good horse!
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Backyard Mechanic
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Backyard Mechanic
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Downdraft carburetors were available in the pre-teens; however not practical until a reliable pressure fuel pump was devised.
Jon.
Good carburetion is fuelish hot air
Owner, The Carburetor Shop (in Missouri)
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i did a fuel injection seminar for NCRS/GM at Nashville in the summer of 2003 for the celebration of the 50 anniversiary of the birth of the corvette. while doing some research on the development of fuel induction for int comb engines, i was amazed at the foolish practices that the 19th century tinkerers employed whilst developing their carb. systems. one do-do ran raw fuel across a pan that was heated from below the pan by a burning flame in an atempt to atomize the fuel. his sory [bleeped] is cinders. check out you local library for the details. mike
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Shade Tree Mechanic
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Shade Tree Mechanic
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Afternoon gents, just quick question on this carb development topic. I believe Carl Benz (or maybe it was Nikolaus Otto) developed an atomizer device that was timed to the engine for his first engine way back in the 1800's. It would force a stream of air across a tube that was sticking out of a fuel resevroir. Sort of like an old perfume bottle works.
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Shade Tree Mechanic
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Shade Tree Mechanic
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Gents, found this on the net, a little off topic but doesn't this sound like a lot like a super charger. Way back in 1861. Proving nothing is realy new in the auto industry, just rediscoverd.
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Shade Tree Mechanic
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Shade Tree Mechanic
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OPs, sorry
a. In 1861, G. Schmidt proposed using a charge pump to compress a
fresh mixture of fuel and air to three atmospheres before it
entered the cylinder, thereby gaining greater expansion.
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