Quote:
Originally Posted by roflwaffle
According to this article, it's not the timing advance that hurt per say, but the very low load.
http://www.swri.org/3pubs/ttoday/Sum...n-and-Cool.pdf
At low loads, you're essentially losing a bunch of heat, and that's what hurts efficiency. When you add cooled EGR, you reduce the peak combustion temperatures, which reduces the amount of heat you're loosing to the block/coolant. You should also be able to increase the amount of advance on cooled EGR to help a little bit with efficiency. Another benefit of cooled EGR, and turbocharging in general, is recycling heat, which helps with efficiency in general. |
I think I'm understanding you correctly? The article you posted is pretty much
what I'm seeing also. I'm referring to high load-ultra lean burn only in my above post on cold EGR.
Going by my Close Cycle Interactive Otto Cycle simulator, I get these numbers.
30.5 A/F = 2500K = .432kJ Wnet per cylinder per cycle
22.6 A/F = 3000K = .557kJ Wnet per cylinder per cycle
14.4 A/F = 4200K = .859kJ Wnet per cylinder per cycle
All three are at 100 kPa MAP and 333K IAT.
Now there is whole other topic of what the true air pressure is after the intake valve closes.
But as a example you can see above what Wnet out is, verse the different A/F ratios, and on my setup going from 14.4 A/F to 30.5 A/F really takes a hit in energy/heat?
Anyway I really appreciate the post roflwaffle. I wish more people on here would comment on this crazy project of mine.
I would love to discuss this with everyone on here.
