Ricardo Wave and the Wankel
08-20-14, 01:41 PM
#1
Ricardo Wave and the Wankel
Hello, I am a mechanical engineering student and also on my universities 2015 FSAE engine team. I will be learning to use the engine simulation software Ricardo WAVE to help with our design process (intake plenum, restrictor, exhaust, etc).
Does anyone have any experience with this software?
How about modeling a wankel?
Once I get familiar with the software I am hoping to model the wankel but any help/tips/do's and don'ts would be greatly appreciated.
Does anyone have any experience with this software?
How about modeling a wankel?
Once I get familiar with the software I am hoping to model the wankel but any help/tips/do's and don'ts would be greatly appreciated.
08-22-14, 06:14 PM
#2
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no experience with WAVE, although it would be really neat. i do have a dyno simulation program.
we do have the port areas and timings for enough rotary engines to be able to cover most of the engines you'd want to model, and for some engines, we even have the hp/tq/bsfc graphs.
my simulator will simulate a 2,616cc 4 cylinder, which is close. i took the Eccentric shaft throw, doubled it, and then changed the "bore" until i had the correct chamber cc's.
mine seems to be built around various V8 flow and hp numbers, so when you don't have a v8, results get approximate. for instance the S2000 must have some magic in it, the computer is way off
some of the rotaries are like this too, for whatever reasons.
we do have the port areas and timings for enough rotary engines to be able to cover most of the engines you'd want to model, and for some engines, we even have the hp/tq/bsfc graphs.
my simulator will simulate a 2,616cc 4 cylinder, which is close. i took the Eccentric shaft throw, doubled it, and then changed the "bore" until i had the correct chamber cc's.
mine seems to be built around various V8 flow and hp numbers, so when you don't have a v8, results get approximate. for instance the S2000 must have some magic in it, the computer is way off
some of the rotaries are like this too, for whatever reasons.
08-23-14, 05:06 PM
#3
thanks for the response, that was clever playing with the bore to match the chamber displacement.
One thing I feel is going to be off is that 4 stroke engines by default have 2 rev/cycle... similarly 2 strokes have 1 rev/cycle. Doesn't the rotary take 3 revolutions per cycle (rotor speed to crank speed? This figure comes up in a lot of engine calculations and would have a large impact on results.
One key parameter this would effect is the mass flow rate of air which is key to efficiently matching a turbo.
What do you think?
One thing I feel is going to be off is that 4 stroke engines by default have 2 rev/cycle... similarly 2 strokes have 1 rev/cycle. Doesn't the rotary take 3 revolutions per cycle (rotor speed to crank speed? This figure comes up in a lot of engine calculations and would have a large impact on results.
One key parameter this would effect is the mass flow rate of air which is key to efficiently matching a turbo.
What do you think?
08-23-14, 07:15 PM
#4
tard of teh century
I remember reading a paper that had good results with either wave or gt suite. I can try and dig up the paper when I get back to work on Thursday if nobody else finds it first. They did have to use a huge bore to capture the inefficiency of the rotary but I don't remember any actual numbers. Your school should be able to get you SAE papers for free if you talk to the professors.
08-24-14, 05:10 PM
#5
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thanks for the response, that was clever playing with the bore to match the chamber displacement.
One thing I feel is going to be off is that 4 stroke engines by default have 2 rev/cycle... similarly 2 strokes have 1 rev/cycle. Doesn't the rotary take 3 revolutions per cycle (rotor speed to crank speed? This figure comes up in a lot of engine calculations and would have a large impact on results.
One key parameter this would effect is the mass flow rate of air which is key to efficiently matching a turbo.
What do you think?
One thing I feel is going to be off is that 4 stroke engines by default have 2 rev/cycle... similarly 2 strokes have 1 rev/cycle. Doesn't the rotary take 3 revolutions per cycle (rotor speed to crank speed? This figure comes up in a lot of engine calculations and would have a large impact on results.
One key parameter this would effect is the mass flow rate of air which is key to efficiently matching a turbo.
What do you think?
for things like turbo sizing we seem to just take the rotary at 2 rotations, which is 4/6 chambers, but it is sort of equivalent to a piston engine.
the other thing about the rotary is that is has more seal length than a piston engine, and when you combine this with longer strokes, there is more time to leak too. this is one reason why the rotary is low on torque.
i would start with a rotary that we have all the info for, and play with the software, remember you're trying to get the computer to reflect reality, and not the other way around.
off the top its either the R100 engine or the Cosmo engine that we have the most complete data set for. the FD engine is lacking the factory dyno graphs, and we have unitless turbo maps... actually the Rx8 is pretty well documented too, its the most piston like of the bunch
09-01-14, 05:28 AM
#7
yes, the rotors are 3:1 so it takes three crank rotations to have a combustion event on all the faces of every rotor, which is 1080 degrees vs the piston engines 720 degrees. this makes each stroke 270 degrees instead of 180.
for things like turbo sizing we seem to just take the rotary at 2 rotations, which is 4/6 chambers, but it is sort of equivalent to a piston engine.
the other thing about the rotary is that is has more seal length than a piston engine, and when you combine this with longer strokes, there is more time to leak too. this is one reason why the rotary is low on torque.
i would start with a rotary that we have all the info for, and play with the software, remember you're trying to get the computer to reflect reality, and not the other way around.
off the top its either the R100 engine or the Cosmo engine that we have the most complete data set for. the FD engine is lacking the factory dyno graphs, and we have unitless turbo maps... actually the Rx8 is pretty well documented too, its the most piston like of the bunch
for things like turbo sizing we seem to just take the rotary at 2 rotations, which is 4/6 chambers, but it is sort of equivalent to a piston engine.
the other thing about the rotary is that is has more seal length than a piston engine, and when you combine this with longer strokes, there is more time to leak too. this is one reason why the rotary is low on torque.
i would start with a rotary that we have all the info for, and play with the software, remember you're trying to get the computer to reflect reality, and not the other way around.
off the top its either the R100 engine or the Cosmo engine that we have the most complete data set for. the FD engine is lacking the factory dyno graphs, and we have unitless turbo maps... actually the Rx8 is pretty well documented too, its the most piston like of the bunch
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