Is one turbo enough for a turbo-compound system? In that case,
I guess the size and boost pressure of the turbo depend on how
much power you want to get for the engine.
Jacobo Guimer�ns
Correct. You will need a big turbo for a 3 rotor.
Paul Lamar
I guess that a big turbo is also needed for a 4 rotor turbo-compound engine.
I'm considering adding a supercharger (a Roots type is the main option)
at the intake manifold, but I fear for an increase in fuel consumption
when I'm looking for the opposite. Would you recommend adding a Roots
supercharger at the intake in a turbo-compound system? What are the
benefits and the drawbacks?
Jacobo Guimer�ns
Mechanical blowers suck HP and fuel from the engine.
Turbo Chargers use the otherwise waste energy in the exhaust.
Paul Lamar
OK, so no supercharger then. I'll have to look for a nice big turbo then.
But still, I have to figure out a way to connect the turbo to the
e-shaft via
gears in order to create the turbo-compound system.
Jacobo Guimer�ns
The big problem is the gear box.
Use what is known as a traction drive. No real gears are involved.
There is a company in Sweden that made them for a awhile.
It was called Rotrex. Super high input RPM on the order of
100,000 Low torque. A ten to one planet set would give you
10,000 RPM
T = torque
To get 50 free HP = 10,000 X T / 5252
50 X 5252 = 10,000 X T
so T = 50 X 5252 / 10,000
so T or Torque = 26 foot pounds of torque. Not much. The shaft from
the compressor side of a turbo charger could be as small as a
quarter inch or 6 or 8 mm.
Paul Lamar
To Jakob: If I were you, I'd consider reviewing, as a basis, elements
such as the Wankel Engine, Internal Combustion, supercharging Wikipedia
articles, the SAE.org database, YouTube videos, and download from the
web documents as the Kenichi Yamamoto and Harry Ricardo books. This will
help in making more focused, narrower scope or spectrum, your doubts,
yielding better results.
Good season, regards, Salut �
Jose Gros-Aymerich
Madrid, Spain
I discovered that HKS has also a supercharger very similar to the Rotrex
traction drive. Here's the link:
http://www.hks-power.co.jp/en/product/supercharger/universal_kit/feature.html
What do you think about it, Paul?
Jacobo Guimer�ns
They must have licensed it from Rotrex. Either that or the patent expired.
We had a long discussion about using it in reverse. Remove the compressor
wheel and feed the power out of the front of your turbo charger with a
small shaft
and small couplings into the Rotrex out put shaft. The normal input
drive shaft to
the rotrex is now the output shaft coupled to the e-shaft with multi belts.
This is risky as I don't know if that will work. Could be the traction
drive feature
in the Rotrex would not take the torque (as little as it is) from the
turbo charger.
These devices are very expensive.
I would try to find a machine shop and make your own planetary 10:1 gear
box.
The gears are probably off the shelf.
Here are some dimensions for the Rotrex parts.
Carrier cage OD is 84mm, 3.307 "
gap is 3 mm so that adds up to .11811
the 90 mm ID annulus 3.5433 ring.
Ring is 7mm thick steel not stainless like I first thought. .27559
Rollers are 40mm OD, 1.574803
30mm long with 1.18102
12mm shafts. .4724409
NSK bearings are light weight # 6001 C3. C3 means loose.
C4 is very loose. C1 is tight bearing.
Pulley shaft is 17mm and has a double sealed regular bearing.
Aluminum case is 129 mm OD 5.0787
105 mm ID. 4.1338
Front and back has 106 mm inner by 122 mm outer
radius for mounting bracket plate.
Here are a bunch of pictures of most of the parts from the Rotrex.
I even had one made at great expense but I never tested it.
The idea is too problematic. Much more straight forward to just build
a planetary gear box.
Paul Lamar
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