Engine Simulations/Analysis

[Richard Lewis]

I'm in the midst of a bunch of simulations using the GT-Power software. I'm curious if any other schools are using this software for engine simulations, or virtual 4 stroke. The GT package is very impressive to be sure. I'd be interested in collaborating with other schools using either package... I have a few things that I'd like to run by someone else familiar with the software, and I'm sure someone out there is in the same position.

Email or reply if interested please. (drax77@shaw.ca)

-------------------------
UVIC Formula SAE Team
http://members.shaw.ca/drax77/UVICFSAEcar.jpg
http://fsae.uvic.ca

[Dominic Venieri]

we've been working with GTI for the past 2 years. 2 of our Master's students have done their theses (spelling?) based on working with it.

www.formularpi.com (http://www.formularpi.com)

[Charlie]

I have been working with Ricardo WAVE the last 3 years. From what I have seen (I am by no means an expert on the other versions) it is by far the most comprehensive simulation software out there, with the ability to simulate drivetrain and transmission as well. This isn't always a good thing and you need to start out small to learn the basics first.

WAVE is great and I would highly recommend it to any team out there. Like FEA, it's not a bible and it's only as good as your inputs. It's taken a couple years to iron out a good verified model, and it's never really 'done'. I'll be happy to answer any questions you have as I've done a lot of simulation research and only applied it to FSAE engines so far.

-Charlie Ping
Auburn University FSAE 1999-present
http://www.auburn.edu/~pingiii/2002FSAE/carblank.jpg

[Alfonso Ochoa]

I'm from Universidad Simon Bolivar in Venezuela. We got the 4 stroke virtual engine the last week. It arrives on january the 7th. We've been working with it since them. Of course we don't know the whole package yet, but it seems to me that it's really easy to use and can give you good optimization of your engine configuration changing the parameters that you want very easily.
I'll be glad to share information with other teams using this software or any other. We are using the CBR F4i engine and would be great to have the whole data you need to put it into the simulation parameters. For example, we don't have the open/close angles for the intake and exhaust valves, the engine manual gives you the angles when the valves are 1mm opened.
Looking forward to hearing from you.

Thanks, email me to: cabezota311@hotmail.com or cotochoa@cantv.net

[Richard Lewis]

Allright I'll post a few questions here.

Big problem for me is that we can't get our hands on a FSM yet, and don't have all the specs for our engine. (2002 GSXR) It's on its way but we need to continue without it. Maybe someone with info on their particular engine can share a bit, as there are a lot of similarities between engines.

I'd be interested in knowing a few specs from you guys with models. (I don't mind if its F4i specs... they are going to be ballpark)

Conn rod length, I. valve diameter, E. valve diameter, wrist pin offset, TDC clearance Height, cam profile... those are the big ones right now, and the difficult ones to measure without dissassembling. I'd be grateful for that info even though it won't be model specific.

Dominic, are you familiar with the GTI software at all? Might have some specific questions for you if you are...

Thanks all.

-------------------------
UVIC Formula SAE Team
http://members.shaw.ca/drax77/UVICFSAEcar.jpg
http://fsae.uvic.ca

[Charlie]

The model is only as good as the inputs. Right now my advice to you is work on the model but expect it to not be a useful tool until 2004. There's not much use in just using a lot of ballpark figures unless you strictly want a pretty picture for the judges.

Yes, a ballpark model can help you predict how the engine will react to certain changes, but I think the restricted FSAE model is unique enough that if you don't get it right, the reactions won't be enough to give you a solid base to make decisions.

-Charlie Ping
Auburn University FSAE 1999-present
http://www.auburn.edu/~pingiii/2002FSAE/carblank.jpg

[Alejandro]

Hi, I'm simulating an cbr 600 f4i with 4-Stroke Virtual Engine. I need the camshaft data to do so. I have the manual whichs tell me the crank angles when the valves are 1mm opened, but I need the exact angles when the valves (int/exh) open and close. I also need the ramp up and down periods and ratios for the intake and exhaust valves. I would really apprecciate you can help me with this, thanks anyway, Alfonso Ochoa.

Alejandro Rondon
Fsae team

[PS]

Hi guys,

I'm using GT-Power. It is a great help as long as you model your engine correctly. The software makes tuning the engine alot easier and it is a big help in tuning intake and exhaust systems.

I'll be glad to help anybody with any questions they have on GT-Power, I don't know that much, but I've done numerous simulations and I learn something new everytime.

Peter.

silsport@hotmail.com

[Bam Bam]

Guys, I can't believe what I'm hearing, you're willing to go through all this work to simulate your engine but you're afraid to take it apart.

Holy $hit!!!!
sure it'll cost about 100 bucks (tops) for seals but come on dude....This is precisely what is wrong with todays ENGINEneers. Most don't even know what the inside of an engine looks like.

Grab yourself a 10 mm socket and torque wrench and go to town. Take the sucker apart if for no other reason than just for $hits and giggles. I mean this competition is about learning.

Models are great but I'd much rather just intelligently screw with stuff on a dyno. WAAYY MORE FUN and at the end of it you have real results that require NO validation or corrections to your model. Just sweet growling horsepower.

Remember first word of engineering is engine not computer. This might indicate where you should be spending more of your time.

sure you can't make expensive mistakes that will destroy your engine on computer but if you're intelligent and careful with your testing you won't either.

[Richard Lewis]

I've pulled enough engines apart to know that there aren't going to be any gains from doing it to this one... Its all about the intake. (well and exhaust)

I feel that opening these engines up is a complete waste of time except for a few minor mods. (oiling system, adjustable cam gears) Personally I'd rather take the time and spend it on optimising the engine than "playing" and wasting my time.

However I agree that people should get experience "hands on", doing that type of thing. I just don't think it is necessary given the task at hand.

-------------------------
UVIC Formula SAE Team
http://members.shaw.ca/drax77/UVICFSAEcar.jpg
http://fsae.uvic.ca

[Frank]

Couldn't agree with you more Richard,

in fact I'd go as far as to say that from the aircleaner to the base of the restrictor is the most important part (assuming a naturally aspirated engine). And they can be developed with a flow bench (I defy you to show me validation of CFD models showing developments of these components).

[Schumi_Jr]

Just out of curiosity, what are you guys trying to accomplish with your engine simulations? I'm not very familiar with engine simulation software, how does it contribute to engine development? Can't you just tune your intake and exhaust using CFD and testing prototypes on the dyno?

I have started getting my hands dirty with ADAMS vehicle simulations and have yet to see any gains. Obviously with a year or so of validation it will becom more useful. Until then I find it a great exercise in understanding vehicle dynamics, but there are probably more gains from physical testing. Unfortunately, while there's snow on the ground ADAMS is all I have http://fsae.com/groupee_common/emoticons/icon_frown.gif

Aaron Johnston
University of Waterloo FSAE

www.eng.uwaterloo.ca/~fsae (http://www.eng.uwaterloo.ca/~fsae)

[Charlie]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by Schumi_Jr:
Just out of curiosity, what are you guys trying to accomplish with your engine simulations? I'm not very familiar with engine simulation software, how does it contribute to engine development? Can't you just tune your intake and exhaust using CFD and testing prototypes on the dyno?
<HR></BLOCKQUOTE>

CFD does not exactly duplicate the kind of flow characteristics needed for engine manifolding. There is a lot more than just flow in there, you have reversion and pulsing with each cylinder. Coupling of CFD models and 1-d simulation is the best way to go about simulation, but 1-d modeling goes a long way to finding proper volumes and characteristics of manifolding. You can do the same on the dyno, and it is a must for verification, however it is nearly impossible to physically test all the alternatives. For example, you can test runner length on the dyno, but only with a given exhaust setup. After optimizing that, you can optimize plenum volume, but what if there is a better runner length for that plenum volume? Also, is the best intake on a certain setup, still the best after you optimize the exhaust? You get the picture.

-Charlie Ping
Auburn University FSAE 1999-present

[Schumi_Jr]

Cool, I guess that's what most CAE is used for- to get you in the ballpark, then you can validate your design through physical testing

Aaron Johnston
University of Waterloo FSAE

www.eng.uwaterloo.ca/~fsae (http://www.eng.uwaterloo.ca/~fsae)

[Angry Joe]

We just got some engine simulation software (forget the name offhand) but go figure, the frigging CD key doesn't work. Hopefully it will be working soon.

Lehigh Formula SAE

www.lehigh.edu/~insae/formula (http://www.lehigh.edu/~insae/formula)

[Nathan T]

I'm using the GT-Suite program and wondering if anyone has taken the time to measure the actual cam lift and flow arrays. Also I'm looking for exact valve diameters, piston and conrod mass and a few other things. If you have any of this info and are willing to share please email me at ntheiss@usc.edu
Thanks