Brumfield Swirl

marc hildebrant

marc hildebrant

Well-known member
Larry and Others....

Could you clarify the comments about the design of the Brumfield head with regard to the "swirling" action to make the mixture burn better ?

I'm wondering if this method is used today, or if it's unique to the Brumfield design. Also, I thought that the original Model A combustion chamber used a unique design to help the combustion process.

Marc
 
remember these maybe one can be adapted to the model A. lol

a selling feature for the 1984 ford tempo was it came with a 2.3L HSC. (high swirl combustion).




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TORNADO is a non-moving turbine shaped device, which creates a vortex or swirling effect to the engine. The result is improved airflow into the engine combustion chamber, causing a more efficient mixture between air and fuel.
 
Mitch is right about high swirl technology beginning in the mid-80s. All the designs I've seen create the swirling action at the runner/port or in the combustion chamber (as Larry's). IMHO, upstream swirl (the Tornado) would be ineffective because of the turns and bends in a factory intake manifold, particularly on carbureted engines where fuel and air (albeit vapor) are coming down the pipe. I think it would just create turbulence while good swirl design creates a very controlled mixing action. Swirl is used extensively in diesel engines because they burn fuel droplets, not vapor. While it helps get to more complete combustion, you can bet the OEMs used it to reduce hydrocarbon and carbon monoxide emissions so their numbers looked good on the window sticker. $0.02.
 
We started developing large-scale air motion in the cylinder called swirl and tumble in the late 80's. The way it works is that you shape the inlet port so that the incoming charge during intake valve open rotates in the cylinder along the long axis (like water going down a drain) called swirl, and tumble (just like it sounds ... end-over-end) with the piston starting to come up. If done correctly, the large scale air motion breaks down into small scale micro-turbulence as the piston rises in the bore. This turbulence helps to speed up flame front speed and consistency for good combustion. The higher the flame speed the less likely you are to overheat the end gasses (charge not yet burned) and cause knock. You also want rapid flame front propagation to reduce residence time at peak cylinder temperatures which helps reduce NOx emissions.
We never tested a flat head combustion chamber where I worked, so I don't know if you can successfully implement good air motion with valve-in-block geometries. Seems like it would be harder to do. Larry B., your experience?
 
So....the use of a swirling motion was started in the 1980's then.
I can see where it helps with diesel fuel, but shouldn't the gas be totally vaporized ?

Marc
 
Keep in mind that during the '80s, fuel injection, particularly, port FI was beginning to take hold and being used on quite a few engines. This allowed the designers to make manifolds that carried only air; the fuel being injected at the port and aimed at the valve area (krswen might add more detail). It's my understanding that swirl was introduced at the port area because that's where the air and fuel are mixed, unlike carbureted engines where at all happens upstream. I believe it actually helps to make the fuel and air into a more homogeneous mixture and aids vaporization. And, of course, reduces emissions. I've seen racing heads with welded and ground cross-hatching in the combustion chamber to try and induce a turbulent condition (swirl?) to aid combustion. Then again, I've seen a lot of weird things on race cars. :rolleyes:
 
I believe the stock heads my 92 chevy c2500HD had on its TBI 350 had some kinda swirls on the intake ports.
 
You want the microturbulence in the mixture in the cylinder, not the port, although it is largely achieved through port geometry. The intake valve has already closed. The reason is as follows: once a flame kernal has been established at the spark plug it expands outward as a hollow sphere. The more wrinkled the surface (like a golf ball) the faster the combustion, which is desirable. Swirl and tumble breaking down to microturbulence does this.
 
am I the only one that thinks the "tornado" does nothing more then restrict air and cost a ridicules amount of money?

Although not combustion chamber related perhaps krswen has an opinion\knowledge about it?
 
just a note to my previous post the 1984 2.3 hsc was carbureted in 1985 it was fuel injected cfi. i believe the swirling was acheived more from the combustion chamber design than the runners.
 
MrTube said:
I believe the stock heads my 92 chevy c2500HD had on its TBI 350 had some kinda swirls on the intake ports.
Click to expand...

Heads today are much better with this. The TBI heads like yours and my 92 silverado are ok heads (which might be a generous statement for the tbi heads) but the newer vortec heads that chevy makes are much better. Seems like swirling in a model a would be much more difficult.
 
I think the question may well have been about the type of swirl/turbulence caused in the chamber by tight clearance ("squish area") between piston top and part of the chamber. Studied and developed by Harry Ricardo circa WWI.
 
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