Monstrobolaxa wrote:The guest is wrong.......it's 4 banks of 3 cylinders.
There is a site with a study that compares W12 with V12 engines....I'm going to look for it and I'll post back later.
thats what i said. just go back and read it.
you cant have an engine that has 3 banks...it just wont work intake/exhaust wise. it wouldnt be efficient i should say.
i read that study a while ago monstro, but lost it, thanks for finding it again its a great read. however, the engine they are talking about in there just happens to be one with 3 banks . . . . interesting. guest, how is it that the engine wont work intake/exhaust wise? what are the problems you run into, for example, is it timing related, or that you just can't fit the intake/exhaust components onto the engine?
yep. You cannot avoid having intake and exhaust in the valley of one bank .No,that ´s not really true,isn´t it?.
You missed a french inventor who did develop a w12 engine for AGS in the 80s .I do not remember his name,but the thing never got beyond prototype work ,later I heard of him doing a car running on compressed air...
it seemed to fit on the drawings presented in the paper, and they looked to be to scale . . . i think you could make it work, at leasst with the angle he used. what concerns me more than the exhaust/intake setup is the width of the engine - yes, it gives it much more torsional stiffnes, and the engine has many ther benefits as presented in the paper also, but i wonder it these are outweighed by the aerodynamic implications of this wider profile. with the trend these days in the design of the rear of the car these days being a very tapered rear end , i wonder if this engine is too wide for that to work, thereby ruling it out as a possibility (pretending that the rules didn't outlaw it in the first place). the only way i can see around it is that because it is shorter than a V10, and with gas tanks being made smaller because rule changes, perhaps the entire assembly could be moved forward enough that there would be room enough behind it to have the end as small as it would need to be to allow the advantages of the engine outwiegh these negative implications on the aero side of things.
Location: Covilhã, Portugal (and sometimes in Évora)
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Hi Guest...I already had read that link....a few months ago...but thanks anyway. I kind of mixed up the definition of banks......that's were the confusion came from.
a 3 bank engine will work, but it would be so inefficient, it would be embarassing. no matter how you set it up, youre goin to have an exhaust manifold heating up one intake manifold, causing one bank to run richer/leaner than the other 2. furthermore, 2 banks could possibly share 1 intake plenum, giving a different wave pattern to the plenum, creating a difference between the 3 banks overall.
ive never heard of a 3 bank/4 cylinder engine. i immediately thought of the VW w12, in which, you have 2 banks of cylinders, with 1 bank having offset cylinders. this is the most efficient design in that you can run a common intake plenum, and exhaust will run out, away from the intake. but, its still inefficient due to the wide head it has to run, adding weight to the overall engine.
everyone here is intelligent, and everyone here should agree that the w12 engine design will always be a failure due to several factors.
im a honda guy. mugen was headed by the son of Soichiro Honda. i noticed in that article that honda gave the engine to Mugen for performance...its only fitting, isnt it? BAR is doing great this year.
im also switching my title to SimplyFast.
Carbon wrote:
Just going back to Becker4's last question, can any of you explain the 2 plane and 4 plane crankshaft design? I've read that some of Ferrari's road cars have 2 plane designs, but I don't know what that means.
Single plane crankshaft simply means that the cranks are all in the same plane (directions 0 and 180°), two planes means that the cranks are at the four positions 0, 90, 180, 270.
The main difference is that with a two plane, alternate forces of second order are 0, while alternate of first order, though not 0, can be equilibrated at the level of the single V with counterweights on the crank. In a single plane crank the forces of second order aren’t balanced and obviously can’t be balanced with counterweights (frequency is twice of the crankshaft rotational speed).
to take things further ,if you choose a bank angle of 72° you cannot get
a even firing order ,as the crank needs 720degrees for a full engine cycle
so this would only be possible at 90 and 180 degrees bankangle to get evenly spaced fireing of all cylinders. In that case you would need to
tweak the Cylinders of one Bank 18° to achieve this.
Just to add that according to G.A. Pignone, author of “Motori ad alta potenza specifica” (highly recommended book if you read Italian), an even firing order is often an overrated property in term of balance, it’s definitively not a necessity, especially for high revving engines. More important is to have even spaced firing for the cylinders of the same bank, but that’s related with the efficiency of the exhausts system, not with the crankshaft balance.
THis is a pretty interesting topic for me. I'm currently a student at MTU and on the Formula SAE team. I've been designing our very first V8 engine for the past 2 years. The engine is a V8, 90 degree bank angle, single plane crank, 550cc total displacement engine. The heads, pistons, and con-rods have all been taken off of the Kawasaki ZX250r in-line four engine. On the original four cylinder engine the heads had red-line RPM of 19,500, so I'm not worried about the valve-train not being able to take the high revs. I have a question though, how would I go about calculating the maximum RPM of the crank-train (crank shaft, pistons, con-rods)? I know I won't be getting the engine in the 19,000 range due to air starvation. We are limited to a 20mm restirctor which has a maximum flow of about 100 CFM, so I'm expecting peak power to be around 13,000-14,000, but I would like to know how to calculate the red-line for this engine so I don't get a driver that buries the needle and blows my engine. Thanks.
