Help wanted finding Inlet runner pressure vs crank angle graphs 1

[Cronik]

I'm trying to find data (graphs, tables etc) that show the pressure in the inlet runner against crank angle. Preferably a whole lot of pics/tables showing the effect that different modifications, different rpm etc have on the wave form.

Particularly interested in high rpm multi-valve un-boosted applications and the effects of helmholtz tuning but all knowledge is good knowledge so i'll look at it all.

An example of what i'm looking for is

http://www.team-integra.net/sections/members/images/2f90dcc7-03aa-4ca0-afe7-d1d4755d9e1d.jpg

So if you know of any good sites/books please post links/references.

TIA

 

[SomptingGuy]

This is bread and butter for a 1D gas dynamics code. They don't come cheap (unless you are a student, but then you wouldn't be posting here!). However, there are some out there with free trials. A quick google gave me several (free to try) hits.

 

[GregLocock]

Always try the NASA/LARC archive server if you want to know something fundamental about engines. At the very least there is an excellent paper on tuned intake lengths.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[AboveRedline]

I don't quite get the graph you posted. If the red line is pressure in the runner, it's 2 psi (55 in H20) at TDC, then as the piston goes down and reaches max velocity the runner pressure goes to minus 2 psi... all good, but why does it spike all the way back up to 2 psi at 120°(before BDC)?

Our experience was these are very difficult measurments to make and properly relate to crank phase and absolute values. That was about a decade ago, what are people during currently?
thanks

 

[GregLocock]

The peak at 120 will be a wave reflected off another valve or the same valve reflected off the plenum.

Making measurements like that would be a doddle using microphones and the analysis gear in an NVH lab - its exactly how we used to invesitgate intake tuning, 20 years ago.

As SG said, any 1D code could do it - in fact you can get a long way in Excel or whatever, modelling it in 1 degree steps. I made a single runner model for a tapered tube into the plenum, for example, to examine how that affected the width and height of the bump in the VE vs rpm graph.



Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[Cronik]

Thanks for your posts Greg. I'll check out the NASA/LARC server tomorrow.
I don't suppose that excel file is floating about on the net at all is it?

SG: i'm aware this is relatively simple to model, i was more interested in looking at real world graphs and seeing what sort of waveforms actually occur in the real world. Part of the problem is that modeling them requires a lot of data that takes a bit of time to collect/measure, and for now I am more interested in getting a general feel for what changes cause which effects.

Thanks to all for their contributions.

 

[SomptingGuy]

Well, if you mean business and have a few $$ to blow, blow them on this book:

http://www.amazon.com/Theory-Engine...208644?ie=UTF8&s=books&qid=1181728284&sr=1-10

Otherwise download one of the codes and play. You'll be surprised how easy they are to set up and get meaningful & representative results from.

 

[GregLocock]

No, my code is in suspended animation. The Lotus engine simulator is a great place to start.

http://www.lesoft.co.uk

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.