Skip to comments.Awesome new(old) engine tech...TURBO COMPOUNDING
Posted on 08/23/2009 7:08:39 PM PDT by mamelukesabre
ARLINGTON, Va. The Truck Writers of North America (TWNA) announced Detroit Diesel Corporations DD15 engine turbo compounding as the winner of its Technical Achievement Award for 2008 during TMCs 2009 Annual Meeting in Orlando, Fla., Feb. 9-12.
(Excerpt) Read more at layover.com ...
Here's an explanation: http://en.wikipedia.org/wiki/Turbo-compound_engine
And the link again: http://www.layover.com/news/article/detroit-diesel-dd15-engine-turbo-compounding-wins--15127.html
Audi used Turbo-diesel technology to win several LeMans races.
Puegot won with turbo-diesel this year.
Nothing new here, except the possible popularity for passenger vehicles in the US big IF the government will allow it.
VW’s Jetta TDI is a 2.0 liter engine, which gives 29 mpg city and 40 mpg highway.
I don’t think you understand. This is not a typical turbo. Read the wikipedia article on “turbo-compounding”.
Does this also help with turbo lag?
That was my instantaneous thought when I saw the thread title.
Increased complexity often equals increased maintenance.
No idea. But in the case of a semi truck, where engines don’t spin up much more than 2000RPMs, I think turbo lag is a moot point. This is more about fuel efficiency than anything else.
The fascinating thing about it is that a compound-turbo engine is the halfway step before going to a turbine engine. The boys at detroit diesel figured out that adding a compound turbo after the regular turbo increases the effectiveness of the new pollution control equipment required by the new stricter pollution regs.
I can’t wait to see what they come up with in the next 20 years.
Computers. they may make the difference between then and now. I guess time will tell.
The boys at detroit diesel figured out that adding a compound turbo after the regular turbo increases the effectiveness of the new pollution control equipment required by the new stricter pollution regs.
You could say that but the way I read it this isn’t your typical compound turbo app where you’ve got turbo’s in “series” with the 2nd getting the last bit of power and engine heat and blowing into the intake ,, in this case the second turbo seems to be connected to a hydraulic pump/motor that drives the tranny output shaft .. the same way a/c compressors are remote mounted and hydraulically driven on many busses and the compressor side of the turbo is not mentioned in the article... it could go to the intake or it could go to waste ... the only thing for sure is that exhaust back pressure is greatly increased as EGR recirc is off the charts.
“Nothing new here, except the possible popularity for passenger vehicles in the US big IF the government will allow it.”
Why should gov’mt have any say whatsoever in this at all?
I have always wondered what happened to turbine auto engines. In the late 50’s Chrysler built 50 Turbine powered cars and put them on the road. Also Truck engines were built, not to mention Granitellie’s Indy cars. No auto since that I know of.
Expensive, poor mileage, poor emissions.
I think you are not understanding what a compound turbo is. A compound turbo doesn’t HAVE a compressor side.
If I'm not mistaken, the rules were re-written to bar turbines from the race.
I agree that the 2nd turbine must be direct connected to the out put shaft as I don’t see how pumping more air into the intake will help any thing, as we don’t use all the output of the first turbo.
Truck diesel engines are already "blowdown" type turbochargers, they don't use superchargers driven by the crankshaft as this wiki article suggests.
Apparently this "compound turbocharged engine" is just a method of using several turbochargers to increase pressures without increasing intake air/fuel flow.
Trucks with a single turbocharger are already running boost as high as 30 lbs, and when pulling a heavy load up steep roads engines are getting pretty hot as it is. Adding more boost will only make those combustion chambers and exhaust gases leaner and hotter.
That's probably the reason why Detroit diesel never got past the development stage with them.
Maybe by using compound turbochargers provides a way to get rid of some of the heat that single turbochargers create in boost air. The more heat you can get out of the air the better. The engine will run cooler and more efficiently, and have more power because the air density will be higher.
I am not understanding why nobody understands what this is.
The compound turbo DOES NOT ADD BOOST TO THE INTAKE! There is no compressor side to the turbo. The turbo shaft is connected directly to the drivetrain. The turbo is DIRECTLY DRIVING YOUR DRIVE WHEELS!
It’s not charging the intake.
LMAO @connected to the wheels. No it isn’t. Where the heck do you see that?
They won’t, they don’t want to increase the supply of diesel in the country.
This goes against the strategy of “Energy Denial” that the libs are executing.
Even though it would be more efficient, they will oppose it because it defeats a bigger goal of destroying the average persons’ energy freedom. If you can get better mileage and diesel’s cost stays the same, you will drive more and this is not good. If they make more diesel so you can all drive more diesel cars and thus be freer, and even though pollution will be down because it’s cleaner now, they don’t want us to have all this energy we can use.
They believe we are using too much, and so they oppose cleaner technology because that allows us to use more without harming the environment (control is important, not the environment); they oppose new exploration and development of US sources of oil and coal and gas (because control is important, not energy independence OR energy abundance); and they oppose the cleanest and newest designs in nuclear (because control is important, not the environment, cheap energy, or clean energy).
They are in the process of taking us down as a superpower. They are forcing us to remain dependent on foreign energy, wasting our money on windmills, they are tanking the currency that will ultimately lead to hyperinflation by printing so much of it but there’s nothing backing it.
We have to get the country back fast or it’s all over and global government and national sovereignty are gone. These people are traitors and need to be exposed as such. This isn’t just incompetence, it’s deliberate destruction and takeover.
Ok, here’s what’s happening. a turbo increases power by boosting the intake. Doing so increases the required fuel to maintain proper fuel air ratio. A compound turbo boosts power without any increase in fuel demand. How? because a compound turbo doesn’t boost intake pressure. It dumps all it’s energy directly to the crankshaft. More power without more fuel or more heat or more manifold pressure.
I think you should understand it now, right?
In WWII, they gave up on the compound turbo because they realized the output shaft of the turbo was producing more power than the output shaft of the engine. So they decided to get rid of the engine all together and just have the turbo...
That’s what we call a TURBOPROP.
If you are dumping mechanical energy directly to the crankshaft, what are you doing?
Answer: Driving the #$^& wheels. Or if it is a plane, you are driving the prop.
Just read the wiki article like I said.
The last of the turbo compounds were used in the final versions of civilian piston airliners (before the conversion to the turbine technology of today)...and also notably the B-29 Superfortress bomber...
That connection at the crank is NOT turbine power going back to the crankshaft, That’s one stage of this compound turbine POWERED by the crank. you can see the boost side tubing running to the intake side top rear of the engine, as well as the exhaust side pipes running to the back of the unit from both sides of the engine to a “t” joint. The crank drives an secondary turbo charger which compresses the compressed air from the primary turbocharger at the rear.
Your compressing air and dumping into the intake. period.
It's not a jet engine, it's a piston engine.
and look at that wiki page, and read it yourself. see the pic? thats a Nomad engine. See that pointy thing after the turbo? thats the air intake for the compressor side of the unit.
But a lot of diesel mechanics would laugh if you tried.
the secondary turbines output is hydrodynamically coupled to the engines drive gears.
I know what that means. i would think you should be able to read it and understand what it says too.
Are you sure it’s not the exhaust outlet?
Huh? Detroit Diesel engines have a LONG history of using "roots" superchargers, in fact the 4/71 and 6/71 "roots blowers" (which later made their way to hot rods and drag racers) were standard on Detroit Diesels (the 8/71 and larger were aftermarket, rather than GMC manufactured.)
Take another look at the design. The "compound turbocharger" is NOT used to increase the intake charge density. What's happening here that the exhaust gasses from a 2 stroke engine power a turbine whos output shaft is coupled to the engine's output shaft, thereby using some of the wasted power from the exhaust gasses and using that to augment the output of the 2 stroke engine.
Regarding the compound turnbsharger, this has nothing to do with the intake side.
A Turbo-compound engine is a reciprocating engine that employs a blowdown turbine to recover energy from the exhaust gases.
When a blowdown turbine is attached to an engine it will not reduce power due to exhaust gas flow restriction,
You can see at this link:
The exhaust-driven turbine is not used to drive a compressor for the intake. Instead it is coupled to the output shaft and adds to the torque produced by the “main” engine.
Just sounds like the exhaust gases drive a turbine which is hydro-
dynamically connected to the drive gears..using waste energy
to help drive the wheels...decent idea.
I suppose this could work with a gasoline engine also. Anyone know
about that ?
How about using the waste heat to power stirling engines which
help recharge batteries in a hybrid?
I wonder if anyone has ever tried this combination:
High pressure(higher than normal diesel in diesel system)
and same in gas engine
Solar cell array on roof,trunklid, engine hood to recharge batteries.
Stirling engines to recover all waste heat(exhaust, cabin temp)
to recharge batteries
Low final drive ratio
Super low coefficient of drag
I wonder if they could apply such considerations on the
Anybody here with a car engineering degree who would know
about these things?
Turbosteamer. BMW is building them.
If I remember correctly, the exhaust melted the asphalt pavement when they came to a stop.
Interesting. I wonder if that recovered exhaust energy would be better utilized by dedicating that output shaft to, say, turning a generator in a hybrid application? Sounds like a natural for a large diesel-electric application - public transit buses, perhaps.
Seems like the configuration needed to return that energy directly to the engine's crankshaft (as per your linked image) would be a challenge in an automotive application. You'd likely have to tie it in to the front end of the crank, rather than the rear (as in aircraft applications).
“I suppose this could work with a gasoline engine also. Anyone know about that ?”
When I was a kid we could fire a potato out of the exhaust pipe of my neighbors’ car. Does that count? ;-)
That is generally the definition of turbo compounding...
You are correct sir...
Ok, but will I get more chicks?
He has been a quest for a while to Turbo-Compound a Rotary (Wankel).
His reasoning is the CW-3350's had issues with the exhaust valves. Rotaries do not have exhaust valves.
Check this page out as well: http://www.rotaryeng.net/turbo-compound.html
Check this out, Pratt and Whitney Canada's Application for a Patent...Turbo-Compounded Rotary
August 2009 Issue of Kitplanes.... Paul Lamar wrote a great article on Turbo-Compounding...
Yes, and the throttle response was......lagging.