Ricardo Wave two-stroke simulation

[Villy]

Hi all,

I'm currently working on my dissertation on a two-stroke hydrogen engine and I have some problems.

I am using the two stroke engine model provided by Wave (si2stroke) and I need to get some plots for bhp, torque, bmep, etc. I added 3 more cases of speed starting from 4000 going to 1000rpm and then run the model. In WavePost, when I go to Sweep Plot and select a 2D plot for speed (Y axis) versus torque, bhp, or bmep (X axes), I only get a straight line for a fixed value of the Y axes along all the rpm range.

Do you have any suggestions on what may be wrong?

Thanks in advance for any help.

Villy

[Villy]

Hi all,

I'm currently working on my dissertation on a two-stroke hydrogen engine and I have some problems.

I am using the two stroke engine model provided by Wave (si2stroke) and I need to get some plots for bhp, torque, bmep, etc. I added 3 more cases of speed starting from 4000 going to 1000rpm and then run the model. In WavePost, when I go to Sweep Plot and select a 2D plot for speed (Y axis) versus torque, bhp, or bmep (X axes), I only get a straight line for a fixed value of the Y axes along all the rpm range.

Do you have any suggestions on what may be wrong?

Thanks in advance for any help.

Villy

[Dan Westerwick]

Under the "sweep plots" category in WavePost, there should be an "engine" item by default. From there, go to "performance", and there will be brake torque and power plots. You can also find bmep plots, but they might not be in the "performance" item.

Hope that helps.

[Villy]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Dan Westerwick:
Under the "sweep plots" category in WavePost, there should be an "engine" item by default. From there, go to "performance", and there will be brake torque and power plots. You can also find bmep plots, but they might not be in the "performance" item.

Hope that helps. </div></BLOCKQUOTE>

Thanks for the reply Dan, I checked on WavePost but I had no "engine" or "performance" item to select, only Time Plots (with some plots on it for pressure, temperature etc.), Sweep Plots (with no sub categories from default), Spatial Plots (empty), and TCMAP Plots (Empty as well).

Any other ideas on what may be the problem?

Also, I tried to check for emissions too and I get zero NOx and CO values for all the range of the rpm.

Cheers,

Villy

[Wesley]

Do you have the correct fuel selected?

[Villy]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Wesley:
Do you have the correct fuel selected? </div></BLOCKQUOTE>

Yeah, I checked it and it is all correct, Indolene in liquid form (I first need to get plots for indolene before I use hydrogen) and the injectors are set to work with liquid fuel.

I also added on the Constants Panel some different values of temperature (higher temp for higher rpm) but again the only plots I can get for either bhp or torque versus engine speed will show a gradual reduction in power the more the rpm rise (but even then, the difference between 1000 and 4000rpm is only 0.4 Nm).

Any more ideas?

Thanks again,

Villy

[Wesley]

I seem to half-remember having this problem once, I'll see if I can recreate it.

[Villy]

http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

I shorted this thing out guys, thanks a lot for any suggestions.

The problem was in the Operating Parameters in the Engine General Panel.

The engine speed was set to "5000" rpm and I had to change it to "{SPEED}" in order for the simulation to use different rpm speed in different cases.

Thanks again for the help.

Villy