General Chat
Q:
What if you took the exhaust gasses and let them expand through a secondary cylinder like an air pump?
For example: You could take an engine like a V8, have one bank of cylinders work in normal 4 stroke fashion, but the exhaust flows into a plenum, which then flows into the intakes of the other bank of cylinders, and those cylinders merely act as a air pumps. Then the the exhaust gases flow out like normal, or pass through yet another stage of cylinders or a turbo to increase efficiency even further. You would need a modified cam profile for the air pump cylinders, since it just has intake/expansion and exhaust strokes.
The whole idea behind this is that you utilize as much of the wasted exhaust energy as possible to increase the efficiency of the engine. By passing the exhaust through a secondary cylinder, it can expand and perform work on that piston, so you can harness more energy for every unit of fuel burned.
I think if this was done with a turbodiesel...maybe with multiple stages of cylinders and turbochargers, thermal coatings, big bore cylinders to minimize the surface area to volume ratio, you could greatly increase thermal efficiency, reducing emissions and increasing mileage by a great amount.
This probably wouldn't be practical for a street car since you're sacrificing power potential by using half the cylinders as air pumps instead of traditional 4 stroke cylinders. But this could be great for semis and freight trains, where mileage is a concern because of the great distances and loads, and a wide powerband isn't needed.
Of course there will be a diminishing return by adding more stages of cylinders, because with each stage the pressure drops and less work can be performed in the next stage. But with oil becoming scarce I think we should make every attempt to improve the efficiency of engines to make the best use of the resources that we have.
1971 240Z
HLS3026814
Post Edited (Nov 16, 8:10pm)
A:
http://www.treehugger.com/files/2006/08/scuderi_airhybr.php
and seach through 2/4 stroke motors. some of them use the crank case as a small super charger.
A:
that is why a turbocharged engines can potentially have higher thermal efficiency then NA motors
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'74 2+2 -- MSA sway bars, Illuminas, Eibach Progressive, Energy Suspension
L28 with MN47, 240Z rods, milled down dished pistons (11.6:1 CR) and 240sx tranny
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committing suicide in small managable payments
A:
im quite sure they already made this pretty much the same thing i forget what manafacture but look down some posts or back a page should be around
Naturally aspirated 300zx made in 1984 2+2
A:
DaneL24 - LOL keep dreaming. This one of those patents that will never see the light of day. First off as the exhaust expands it looses energy so the air pump you wish to turn will now be turning slower than the original combustion. The differences in rotational momentum would be very tricky to compensate for + the added weight of another block/air pump & clutches, transmision gearing ect. Also you are still burning a carbon base fuel. Using the exhaust from this to turn air pumps or turbos does not reduce the pollutants in it. Processsing it (scubbing) afterwards does.
You want to save/reduce petroleum use. Stop taking air flights, get the USA & foriegn armies out of Iraq, stop building armies that are powered by carbon base fuels, dont buy anything Chineese & stop selling crude oil to China.
This whole world smells bad, I'd buy another if I had
back what I paid for another mother@#$%@# in a motorcade
A:
First off, this is a repost.
Efficiency is not gained by piping exhaust into dead pistons on an engine.
For thos that want to "save" the planet,
Of course environmentalists give a damn about the world around us...but their view of the world is simply wrong (that the world around us should be as static as a painting). Extinction is what this earth is about. Climate change is what this earth is all about. Drought and flood and glaciers and melting and elNino and erosion is how the earth works.
What is abnormal is the environmentalist think that weather and climate and glaciers and species should never vary from what they saw when they were kids. That's simply dumb.
Post Edited (Nov 17, 11:06am)