Ricardo Volumetric Efficiency results

[UNSWTIM]

Hi there, I am currently working on a ricardo model and have managed to get a volumetric efficiency curve that peaks at about 1.1 (110%) for a naturally aspirated engine.

Has anyone run into this problem before and what did you change/check to rectify it. The problem is, it could be any number of things (valve timing, geometry, flow coefficients) but ive checked most of these params and they seem fine.

Im hoping some suggestions will bring up an area I may have missed.

Thanks in advance for the help

[TorqueWrench]

Who says it isn't possible to get above 100% volumetric efficiency on an NA engine at a certain point?

[UNSWTIM]

I was thinking the same thing, with proper intake/exhaust design you should achieve that little 'supercharging effect' before the intake valves close, however I was not of the opinion that this effect would give you above 100%. I thought it would give say from 85% up to 90% VE.

[Adambomb]

Yes, pulse charging is a beautiful thing. 110% doesn't sound too ridiculous, assuming the rest of the model looks good. If that's the case, then I'd say you're in great shape.

[cjanota]

I read in a race magazine (forgot which one) that F1 engines can get up to 115% with a well designed exhaust.

[DonMolina]

An unrestricted Yamaha FZ6 can get up to 100% eaaaaasily. The R6 engine sustains even higher ratios at the top end.


Getting past 100% is totally feasible in FSAE applications with the resictor, and 110% is realy an optimistic number. But if you have put the effort (and mind grease) in your model and your design, I think it is not impossible...

[samphlett]

Yep, while it's technically impossible for the F1 drivers to give it 110%, it's well within the capability of the engines.

[kapps]

Originally posted by cjanota:
I read in a race magazine (forgot which one) that F1 engines can get up to 115% with a well designed exhaust.

I'd say closer to 130-140% on F1.