Tube - exhaust manifold

[jwebleyj]

Hello everybody,

What I am trying to do is draw a four into one tubular exhaust manifold. The tubes will run between two planes at right angles to each other. The planes have center points on them. I imagine I need to do a 3D path for each tube, then sweep the profile along the path. My problem is how to make the ends of the paths co-incident with the center points placed on the work planes at each end. I would also like to force the last 30 - 50 mm of the pipes to be normal to the planes. Any ideas on how to do this please?

 

I'm using Inventor 11 for this.

[shift1313]

i wouldnt try to do this all at once, draw a collector and then your runners. If you draw a collector say from your lager diameter down to a 4 leaf clover shaped segment that will match your runner OD. Then when you are drawing your 3d sketch you can use the center point of each one of these "leaves" to snap to. You will need to use loft for the collector and use sweep for the runners.

 

ill try to draw something up real quick to show you.

[shift1313]

okay i managed to squeeze in a drawing between other things to give you an idea. Here are a few screen shots. I drew the collector sketchs first, did a loft between the two, then i drew my 4 circles for the primaries at the head(where your flange would be), then i drew my 3d sketches. For my 3d sketchs i used a tangent constraint at my collector plane and at my header flange plane. i drew all straight lines and used the Bend with my radius of bend and applied it to all the hard corners. I didnt give anythought to this layout so i know a few tubes intersect:)

oh yeah i drew everything as a solid and used the shell command to get my tubing. all in inventor 11pro

[jwebleyj]

That looks pretty well what I'm after, thank you very much. As you suggested I have already drawn the collector box (did it as a weldment). The flanges are also drawn on the other plane. I was having trouble with the 3D paths, but your suggestion of the tangent constraint has fixed the problem I reckon. Great, thanks once again. We are not alone, as they say.

[shift1313]

good luck with it and let us know if you get stuck on anything else. the catch to the 3d path constraint is you need a plane, unlike 2d where you could be tangent or perp to another line. The drawing part is easy, i think figuring out your paths will be the hardest.

 

are you actually going to build this? and what motor is it for?

 

One thing i have seen done for making collectors is waterjet or laser cut an "X" that will fit between your 4 tubes. weld from the inside. then 4 pieces to fill in the outside to make a rectangle.

 

good luck with the project.

[enforcermike]

sorry to bring back an old thread..

 

but i have a few questions to ask.

 

Background

I've been asked by a mate to design a set of headers for his car. Now i spend all my time design sheet metal for work, and haven't really played around with making pipe systems.

 

problem

 

which way to design it:

1. make each runner 1 model, and just join the runners, header plate and collector into an assembly.

or

2. make each individual piece and join them in an assembly and route the path that way.

 

Method 2, I think will take the longest and will create the biggest library of parts.

 

Method 1, is where I am having issues. the change of directions with the bends etc. is puzzling me.

 

what the best way to go about it?

 

cheers Mike

[shift1313]

welcome mike. Are you planning on using this model to create the header? Or do you just plan to make it as a reference drawing? If you plan to make a bend list or something i would probably model each runner as its own part.

[JD Mather]

Method 1, is where I am having issues. the change of directions with the bends etc. is puzzling me.

 

http://home.pct.edu/~jmather/content/DSG322/Inventor%20Tutorials/Inventor%2011%20Tutorial%207.pdf

 

If you can tie a knot you should be able to run any path.

 

The tutorial was written for Inventor 11. It is a bit easier in later releases. Especially 2010 as you can do multi-body solids and push out the individual parts.

[enforcermike]

welcome mike. Are you planning on using this model to create the header? Or do you just plan to make it as a reference drawing? If you plan to make a bend list or something i would probably model each runner as its own part.

 

Thanks for the reply.

 

the drawings will be used to get a production run done, so creating a bend list would be a good idea.

 

htp:/home.pct.edu/~jmather/content...torial%207.pdf

 

If you can tie a knot you should be able to run any path.

 

thanks for the tutorial, I will have a look at it

[Tankman]

Looks like nice work.

 

Should the piping have flange, bolt on connections?

[eribiste]

The pipe ends at the cylinder head face would have flanges brazed on to suit the engine in question. Years ago I had a four into one manifold hand made by a chap called Dave Boxall who ran a company called Specialised Exhausts in Twickenham. The pipes were 2" diameter, each one the same length. This wizard bent lengths of gas welding filler rod to get the shape. The correct length of tube was fitted with a wooden bung at both ends with the tube filled with sand. Each of the four pipes was then hand bent using a gas torch. When done, the bungs were removed and the flange ends of the pipes formed to fit the pre-cut flanges. These were then brazed on. The collector box was secured to the pipes with small tabs welded to the pipe and the collector box and a split pin passed through the tabs. The fit up was a Cosworth BDG engine in a space frame special saloon car for circuit racing. A master of his craft, it was a humbling privilege to watch this chap at his work.

[shift1313]

Depending on the material and filler used, is a braze joint really the best? Turbo application see 1200-1500 regular temps. NA engine can see 1200F as well. I would think this would be a little high for a pure braze joint. A braze weld joint or a tig welded joint would be better.

[eribiste]

You're quite right about modern temps. This job was done in the seventies when a respectable output for a race engine was 120 bhp/litre. That's shopping trolley power now! Also, the flanges are bolted up to the cylinder head, which is cooled to much less than the melting point of aluminium and presumably the heat at the flange is locally less than the rest of the pipe. The pipes themselves glow bright orange, which puts them at about 970 C!

 

John

[shift1313]

i suppose if your flange is thicken enough to sink some heat it would drop the temps down.

 

Modern F1 engines get what 1000hp/liter I know NA motogp bikes push 250-300hp/liter. must be nice

[kinglevel]

hahaha, i talked about this with my brother yesterday. He said "can you make me a exhaust for an engine with turbo and print a drawing with parts for me"?

 

Yessss, that would be possible, but its a lot of work i think..

 

The big problem is, equal length of every channel (parameters with 3D splines? hmm), unfolding those things... and thats my big hunting question these days..

 

Take a look at this:

youtube.com/watch?v=FWBnEEPdbNE

 

I use frame command, couse its very easy to use.. simple and fast..

 

Any ideas of all this?

thx..

[shift1313]

equal length isnt all that important:) If you use curves to drive your tube sweeps you can measure the arc length of these curves. I dont recommend using splines but rather straight lines and arcs with know radii. In the real world you will probably buy pre bent Us or Js. I figure out what tubing i have/can get and go from there.

[shift1313]

here is a non equal length turbo header for you:)

[kinglevel]

here is a non equal length turbo header for you:)

 

hmm. ok.

My father says it depends, and he wants equal length..

 

I tried to use tubing with bends, can i set an length and it will generate an good path?

Would be great..

[kinglevel]

http://www.pdm-racing.com/products/imag/Megan_SR20DET_Manifold_big.jpg

 

or

 

http://www.horsepowerfreaks.com/images/products/HorsepowerFreaks/Turbo_Kits_HPF_GT35R_Mani_LRG.jpg

 

I mean, why would they do something like that? Its easier to just drag straight pipes?

[basiow]

Thanks for the tutorial