Ports in a 4-valve head
Ports in a 4-valve head
(OP)
I wonder if someone could tell me the method that is used in making an intake or exhaust port. The approaches I have tried have failed. It must be possible, because there are many pictures around (even in the Soldworks start up screen).
I am trying to do this with lofting. There are a pair of round profiles in the combustion chamber and an oval profile on the side of the head. There is a path between them that makes a couple of jogs in different planes.
Every variation refuses to recognize the path. I tried making the path in 3d sketch view, and then with individual lines in different planes except I can't join the lines into a single path. I tried the piercing constaint between path and profiles.
Since I am new at this, if someone could suggest the methodology, I could come back with specific questions. Anything is appreciated.
Thanks
John Woodward
I am trying to do this with lofting. There are a pair of round profiles in the combustion chamber and an oval profile on the side of the head. There is a path between them that makes a couple of jogs in different planes.
Every variation refuses to recognize the path. I tried making the path in 3d sketch view, and then with individual lines in different planes except I can't join the lines into a single path. I tried the piercing constaint between path and profiles.
Since I am new at this, if someone could suggest the methodology, I could come back with specific questions. Anything is appreciated.
Thanks
John Woodward






RE: Ports in a 4-valve head
http://www.EsoxRepublic.com
RE: Ports in a 4-valve head
????
RE: Ports in a 4-valve head
I have many years of Autocad experience and I can layout some pretty complex designs in 2D, but with these solids programs I am spending too much time just trying to work around the system to get things to work.
I don't know how they arrive at all these nice pictures of engine designs such as seen in the SAE magazine, unless it is just marketing bull.
I really hope that I am wrong,
John Woodward
RE: Ports in a 4-valve head
RE: Ports in a 4-valve head
Re, Your second post
AFAIK Guide curves need to intesect the sketched profile, not the centre points for lofting.
Some one please correct me if I am wrong
RE: Ports in a 4-valve head
DJW- that might be my problem, although it isn't clear to my what is meant by intersecting the profile. If I have a circle for the profile, do I need to offset the guide curve from the center of the circle to its edge? Sounds cumbersome but I will try it.
Thanks
RE: Ports in a 4-valve head
Two separate round profiles will not follow their individual paths to a single oval profile.
One round profile will follow a path to the oval, but the result is not satisfactory.
I am forced to conclude at this time that Solidworks cannot be used to create merged intake and exhaust ports in an overhead cam engine. It could not be done with MDT5 either. At least with Autocad you can show in 2d what your intent is, and spend less time doing it.
RE: Ports in a 4-valve head
RE: Ports in a 4-valve head
Cor- now that I have finished with my rant, I hope to wake up with another idea in the morning. I think I can make this work but I think it will be something less than what I really want.
Interesting comparison- at the last place I worked we tried to get Pro-E. They wanted something like $50 grand a seat with a special work station. I couldn't understand the work station (Sun?) concept, but then I am dumb about computers. They finally bought Ideas. Now I sit here with Solidworks on an old slug computer and it works ok.
John Woodward
RE: Ports in a 4-valve head
Yes the guide curve must intersect the circle/profile edge. Well as far as I know anyway - what version of SW are you using?
RE: Ports in a 4-valve head
Guide curves help connect these profiles together maintaining their relationship according to the way the guide curve is made and attached. With your guide curves I'm sure the 3Dsketch curve is going to be necessary.
IHTH - Regards,
Scott Baugh, CSWP
http://www.3dvisiontech.com
http://www.scottjbaugh.com
RE: Ports in a 4-valve head
In the loft command, select "Centerline Parameters" instead of "Guide Curves" and put your path in there. This option is meant to work like a path where the guide curves are meant to control individual vertices in the profiles.
RE: Ports in a 4-valve head
The resulting port is good enough for now so that I can move on. I hope to come back to it after I get some more knowledge and experience. I probably need to learn more about making the guide curve and adding more profiles.
Thanks for all the tips.
RE: Ports in a 4-valve head
RE: Ports in a 4-valve head
Here is what I have done in the past--works very well. I have the same shape formed with a sweep (handle), except in positive form in a hand-held horn on my web site. Tricky at first, but not too hard to do with a sweep.
Here are some tips (not in this order necessarily):
1. Figure out the center of your path. This will be your "path".
2. Use an ellipse for your profile. An ellipse can be round where you need it to be, then morph into the oval you're looking for later when you need that form. This is controlled by your guide curves.
3. Your hole shape will be controlled by two guide curves. It sounds like your path will have a bend or two in it, but that this bend will at least be planar (I hope). If so, you will make one guide curve to govern the X axis of your ellipse and another guide curve to govern the Y axis of your ellipse. If you have a bend or two in your path, you may want to extrude a surface and then project one of your guide curves onto that surface to govern your X or Y axis in your ellipse.
Doing these things, you can form very complex geometry in a very stable way.
If this doesn't work, I'd be willing to look at your part and see if we can come up with a solution. I love this stuff.
Jeff Mowry
Industrial Designhaus, LLC
http://www.industrialdesignhaus.com
RE: Ports in a 4-valve head
Your solution of creating 2 separate lofts for each port is correct. Creating a fillet to remove the sharp edge seems sensible, and from a realism point of veiw, it actually makes sense also.
With regards to other programs, I don't think anything else would handle 2 separate entities going into one in one single step.
RE: Ports in a 4-valve head
just a thought
Regards,
Jon
jgbena@yahoo.com