turbocharging terminology abused
 

I have noticed on discussion forums all over the net, that turbocharging terminology is abused. For example widely spread 'compounded twin turbo' -phrase actually is something totally different than a set of so called 'twins'.

May I humbly suggest we'd start using actual, verified, turbocharging terminology on this board.


2-stage turbocharging
Two-stage turbocharging
A set of two turbochargers, where one charger is force fed by another.
Reference:
http://www.holset.co.uk/files/2_5_1_...bocharging.php
http://www.turbos.bwauto.com/en/products/r2s.asp

Turbocompounding
A turbine in the exhaust flow, that has a shaft mechanically connected onto engine crankshaft or transmission.
Reference:
http://www.holset.co.uk/files/2_6-re...y%20firsts.php
http://www.holset.co.uk/files/2_5_1_...d%20system.php
http://www1.eere.energy.gov/vehicles...er_hopmann.pdf

Are you from the States originally?

Nope, I'm a foreigner. Been to USA only once, on a vacation.

Over the years I've tried to absorb as much of English grammar/language, as my limited learning abilities allow me to obtain.

Huh I coulden't tell if you were messin with me or not, but either way alot of what is said around here is just slang because it would take to long to be politically correct. Remember we are lazy.

That is some very interesting stuff, I've never heard of such a critter!

But good luck getting everyone to use the "correct" terminology.
All the slang and abbreviations can be confusing at first, but after a while you figure out what everyone is talking about! (I'm still learning)

What about the "lag" that everyone talks about? (most of the time they're referring to boost threshold)

While it would be ideal to use completely correct terms, I don't think it will happen.

AWW come on guys!![roll] Keep it simple for us Red Neck Americans.
You start throwin those words with more than 5 letters at us and we are totally lost.[dummy] [laugh] [duhhh]

Ya that is what I am sayin, you ain't dealin with a bunch of chemists hear, you have the western cowboys the southern hillbilly's the cali pretty boys and all the other TRUCK dudes.

And please nobody take offense to anything I said I am a cowbilyprity.[laugh]

I got you beat I'm a yankcowbilyprity. Live North, West, and South!! [laugh]

__________________
Do I got that about right or could one of the gurus correct me?
stand corrected - - thought the picture of that thing had a belt pulley on it like an SC.

[laugh] [duhhh] I heard you guys are really confused all the time.

The compound systems that are being referenced in the links isn't any kind of supercharger.....if you look more closely at the diagrams it shows a system with a turbo charger that has another turbine down stream of it that doesn't drive a compressor but instead the down stream turbine drives a transmission that in turn is connected to the crankshaft - the turbine shaft literally connects to the crank to provide further crankshaft hp and allows the engine to become more thermally efficient.

Actually turbocompounding isn't like a centrifugal supercharger. Turbocompounding has an exhaust turbine mechanically linked to the engine crankshaft through reduction gears and usually a fluid coupling. The reason is to salvage some power from the spent exhaust. So think of it as the turbine is adding power to the crankshaft instead of being used to turn the compressor on your turbo.

There was only one widespread application that I know of that used turbocompounding. This was in the Wright R-3350, an 18 cyl radial aircraft engine. There were some later versions (after WWII) that were turbocompounded with good results. You'll see them called PRT's (power recovery turbines) in these applications. They were mainly used on some Lockheed Constellations.

Artsi you are close, but not exactly correct.

A 'turbo compound' as you describe it would usually be called " a turbocompounded engine" and as you state the waste heat of the exhaust gasses is used to drive a turbine which is mechaniacally connected to the engine shaft, through a gear reduction unit of hellacious ratio. These are extremely common on very large marine diesels and on large stationary diesel engine driven generators.

But using the phrase ''compound turbos" for twins as we arrange them on our hot rod trucks is not in error, and is in fact totally and completely accurate as well. It is derived from the turbines being in series with each other, and has its roots in steam turbine technology that is 100 years old. When two turbines are arranged in series with the first one taking the highest pressure and temperature, and expanding the gasses only partially, then exhausting to another turbine where the expansion is completed, this is call a compound turbine. In power stations, you will find tandem compound steam turbines where the high pressure, intermediate and low pressure turbines are coupled all in line turning one generator ( Look in my photo gallery for a picture of a ~1,000,000 HP one) and the other type of compound turbine in lots of power stations is a cross compound steam turbine, whereby the high pressure and intermediate pressure turbines are coupled together and spin one generator, while the low pressure turbines sit off to the side and spin another generator, but the steam is still flowing through the machines in series... hence the name compound, and its totally aplicable to how we arrange twins.


Kp

artsi L do you even own a ctd or just trying to start something [laugh]