General Motors wants better performance from its boosted engines, so it headed to the patent office with a design for a new two-stage turbocharger — one that eliminates the drawbacks of the existing setup.
According to a document published by GM Inside News, the General filed the patent on May 19. The design (mated to a four-cylinder engine) isolates the low-pressure and high-pressure turbines, calling on one or the other (but not both) at different engine speeds and loads.
In a conventional two-stage setup, both turbines operate simultaneously at low to mid engine speeds, with only the low-pressure turbine working at high engine speeds. The two sides are never fully isolated, which compromises low-end performance.
Like a parent dealing with squabbling kids, GM decided to separate the two. In its design, the high-pressure turbo connects to the exhaust manifold via a high-pressure inlet duct, with the low-pressure unit connected to that channel via a low-pressure inlet duct. Depending on engine speed, an ECU-guided actuator located in the exhaust manifold opens opens the high-pressure inlet duct while closing off connecting channel, or vice versa.
The design aims to lower pumping losses while boosting the efficiency of both turbines. According to the patent, “maximum available enthalpy is given to the LP stage (low pressure turbine) in full power operation and to the HP stage (high pressure turbine) in maximum torque operation.”
Expect to see the turbo lag-reducing technology added to GM’s four-cylinder engines in the future, with the high-output 2.0-liter being a likely starting candidate.
[Image: General Motors]
I’m no GM fan. But GM has made automotive breakthroughs over the years.
Can’t resist this comment, I will respond with a list.
The Vega and particularly its motor.
Cadillac V-8-6-4
Cimarron
Aztec
V-8 Diesel
X-cars
The list could go on and on . .
Plastic intake manifolds… pot-metal door handles…
http://patents.justia.com/company/general-motors
The Automatic Transmission
Airbags
Electric Starter
VVT in a Pushrod V8
Electronic Anti-Theft system
The list could go on and on..
Dodge had VVT in a pushrod engine (the Viper) before GM did didn’t they? At least that’s how I remember it with that funky cam in a cam arrangement.
@ Jeff,
Dissimilar metals shouldn’t be an issue with the advent of MLS gaskets they allow the block and head to expand at different rates and can handle a lot of cylinder pressure.
Prior to an MLS gasket O-ringing the combustion chamber (milling a receiver groove I. The head and using a metal ring) was a thing in thextreme performance industry. It’s pretty much a thing of the past unless it’s a really radically boosted engine.
In any event the side benefit to a multi-layer steel gasket is that the heads and the block can move freely without compromising the seal.
Plus one on the Vega motor. It was made of aluminum, so the first time it overheated was its end.
except it wasn’t aluminum which was the problem. I mean, the Nikasil blocks used by some German automakers today is pretty darn close to what GM did on the Vega. The problem with the Vega 2300 was two-fold:
1) an under-spec’ed cooling system which was prone to letting the engine overheat, and
2) an open-deck block which would distort when the engine inevitably overheated.
GM has made some major POS over the years including many of their current models. But overall GM has had many breakthroughs in engineering and hundreds of patented innovations.
There were no liners – iron or otherwise – just steel rings grinding aluminum walls. That nikasil is the difference between 10,00 miles and 200,000 miles.
and 3) In order to cut costs, they cast the *cylinder head* in iron, which expands at a different rate and contributed mightily to blown head gaskets and overheating.
Chances are, even with the undersized cooling system the engine would be okay if it were all-aluminum.
How can we forget their remarkable move from RWD to FWD across the board, it nearly destroyed them, while others thrived, despite it.
“…while others thrived…” Do you mean Toyota? GM’s failings of the 80’s was not the shift to front drive, it was building low-quality cars. Front drive is now de riguer even for BMW, at least for the small cars, and the Impala and Avalon of today show that it works for large cars, too. Time to accept a more complex view of the world, Corollaman.
Correction; it was the perception of building low quality cars which killed GM.
No doubt they blew it in the late 80s to mid 90s. But the cars coming out of GM in the late 90’s were competitive .
Yeah the interior gaps were bigger, and the styling didn’t conform to European mores. Yeah the BMWs and Audis got more press and more awards.
Yet most Eurocars from that era are ether in the hands of die hard enthusiasts, or the scrapyard. A small remainder are in transit upon the backs of flatbeds. Tight interior gaps won’t mean jack when the turbo blows or the EML light comes on.
Quality to me doesn’t stop when the lease ends. Quality is a car you can start most of the time, and fix on a working man’s salary when it doesn’t.
LS1Fan, while GM had improved their quality and reliability by the late 90s, they were cutting cost in ways that leave a “low-rent” impression with potential buyers. Lots of cheap plastic from the Dollar store side of the tracks. The Cavalier, Malibu, and Lumina are cockroach cars. Relatively tough to kill, but never desirable even when new.
In essence they gave up making cars and pumped out low tech , low epa, low safety SUVs, and coupled this with sub-prime financing. As soon as gas prices rose they were fucked like a vega on a hot summer day.
GM’s car in the 90s were NOT COMPETITIVE.
Typically I see the Japanese in that era last into 200k (ok, mostly Toyota and Honda, but a few Nissan mixed in), and GMs barely break 100k before it becomes “worn out”. Drivetrain still works most of the time but it got worn out and sold into the slum dweller instead of staying in the possession of the original owners.
Their cars are not competitive until well into at least 2006 if not 2012.
This is not accurate. The cynicism of GM did it on their small cars, wanting to give people a bad experience, still in that captive market mindset that they would upgrade to a better car from GM because they had no other choice…
The Chevette was a horrible vehicle. It did a real number on their reputation. You could stick a pinkie through the sheet metal. The doors wobbled. It smelled funny. It was rear wheel drive.
The Cavalier, for all the bad press it got, was better than the Chevette. It was more reliable. It did not fall apart. It was underpowered and it was cheap. However, I knew lots of people who kicked the crappy Chevette to the curb and upgraded to the Cavalier.
The Cavalier was front wheel drive.
@ MrGreenMan.
ABSOLUTELY. The GM pickups of that era were very good. I distinctly recall the stark interior and quality differences between a friend’s Silverado and another friend’s Lumina. The Lumina was a joke used to get people into an SUV / Truck.
The same true with Kodak which invented digital camera and may be Xerox too. American companies somehow pretend that the world outside of US does not exist and can be ignored. With Europe it might work but with Japan they made a grave mistake.
I can’t speak for Chrysler from that period but Ford was the same. They let their car division languish compared to their trucks. Even something as important to them as the Mustang was pushed off to the side and left to mostly wither during a good portion of the 90’s. It was especially telling when they foisted the 4.6 on the Mustang which was supposed to be an improvement over the old pushrod 5.0 yet (as my old man used to say and in this case pretty spot on) “about as useless as a limp dick in a whore house”.
The 4.6 SOHC was too underpowered for too long. Should have gotten the PI upgrades by the time it was put in the Mustang.
Agreed NoGo. I’ve thought the same thing for many years. While the Mustang sold pretty well Ford gave it almost zero investment ( well Probe debacle aside) until the New Edge cars. Prior to that all,the gave a crap about were trucks.
I wonder how they get the flaps in there if the exhaust manifold is cast as part of the head. Downstream assembly maybe?
Skimming through the article it looks like they use two butterfly valves simultaneously controlled by the ECU.
It’s an interesting concept but I can imagine the costs associated with the added complexity will be somewhat substantial.
First direct injection, then turbos and now compound/twin turbo set ups. I wonder what other tech they will borrow from the diesel world next.
Unlike Toyota who has slim failsafes for their software and controlling electronic throttle body’s, GM has, and has for over a decade when Toyotas were suddenly accelerating for no reason, a stout program for their electronic TBs. It wouldn’t take much to to add another TB and control it as they use the it today to control torque outputs in their turbocharged engines.
Looks like hot tub plumbing around a 4-banger.
And I don’t see no turbans.
As I read the description, I keep picturing a compound turbo system, which is not a new concept. True, I am fairly stupid, but I know enough to want my Cadi equipped with a V8!
Volvo has also come out with a new compound set up on their 13L engines.
They have a fixed single turbo plumbed in the traditional sense. Then they installed a turbine wheel in the exhaust flow connected to a fluid coupling which turns a series of gear reductions that turn the flywheel.
Volvo claims it adds 50HP and 125 lb ft of torque.
@EAF,
My XTS VSport with 3.6TT and an ecu tune would like to show you what almost 600 lb-ft of torque through all wheels feels like.
“And I don’t see no turbans.”
They may have been afraid to show the turbans in the illustration, given the anti-Muslim attitudes that are prevalent…
Coming to the new Cadillac exclusive diesel and small block V8.
This is a step forward, especially for the lower capacity turbo engines that don’t have much bottom end torque.
I don’t know how much fuel this will save and how reliable this setup will be. The EGT is very hot on a gasoline engine compared to diesel. A diverter valve setup will be in this very hot gas stream.
One day we will have twin spool compressors and turbines each on seperate shafts, but this will cost a significant amount of money. It is still better to have two independent turbo charger units or even three as is used with BMWs 3 litre in line 6 diesel.
This hopefully will work well and the costs are affordable, don’t forget reliability.
Gasoline engines run hotter than diesels. Again reliability.
Al, for once I agree with you. This has 8-6-4 written all over it. But the rest of the industry will license the patent or find a workaround, and make it last 500K km.
This hopefully will work well and the costs are affordable, don’t forget reliability.
You hint at the thing that will determine the success or failure of this technology. Can GM make money on it? Will manufacturing and warranty costs be within expectations?
I don’t trust GM regarding turbo engine reliability. Heck, outside of Honda and Toyota (and diesel?), the words “reliability” and “turbo” don’t really belong in the same sentence. But this should be especially true of GM.
Heck, I liked the Cruze. I would recommend it over the Corolla, but NOT with the turbo motor…
“I don’t trust GM regarding turbo engine reliability.”
39 month lease FTW. Let the CPO guy or the third owner worry about it.
Buddy of mine has a Cobalt SS with GM’s DI turbocharged four. He has daily’d the car right up until this year and no problems. The guy drag races the car and makes really bad decisions when he goes out to party like letting his cop running friends pull pilot duty when he is too smashed to drive. Its been pretty reliable overall (torsion beam real axle aside).
And I say this as a DI skeptic
Turbos replace engine displacement, so the more efficient the turbos, the less displacement you can get away with. But when it comes to cooler EGT of diesels, those days are long gone. We have something called “diesel emissions” equipment on this hemisphere.
DenverMike,
Can you furnish a link actually stating that modern diesels run hotter or even as hot as a gasoline engine.
Again, are you trolling?
A link will suffice, with none of your usual bullsh!t commentary to divert from the statement you made.
Gas engines typically operate just under 200 F with EGTs just under 1,200 F, under heavy load cycles. Diesels typically operate over 200 F with EGTs over 1,200 F, under heavy load cycles.
Obviously we’re not talking hi performance gas engines, WOT on the dyno, nor pre emissions diesels.
thedieselstop.com/forums/f16/what-typical-gasoline-exhaust-temperatures-16309/
Have you driven a turbo-4 with VVT and DI lately? A manual transmission version will knock your socks off!
Who cares. Gasoline engines are thing of the past. I think pretty soon they will be outlawed in most developed countries.
Let’s not get carried away. There are still hundreds of millions of gasoline engines produced every year, and there is room for improvement on all of those.
In 30 years or so given the time table most countries who have set out to ban them already.
A lot can happen in a quarter century.
Hell look at the EU. That from what I’ve read was a 43 relationship/process with ritain and it could very well fall apart in our lifetime as well as Great Britain itself.
While I don’t know if anything has been done to counter China’s stranglehold on the rare earth market. They could certainly extend out the time it will take to electrify the US raid fleet if they get pissy about something.
Don’t hold your breath.
I for one do NOT welcome our new four cylinder overlords.
(at least not in “performance” vehicles)
Here’s the real future of ICE powered cars:
http://www.youtube.com/watch?v=xEiaTpoQQJ0
HELLMOWER!
I wonder if the future of autonomous cars will even allow us plebs to exceed the speed limit (I do 5 or 6 over, but it’s still technically “speeding”). At that point it wouldn’t matter what was under the hood anyway. Ugh, I grow less excited about cars each year.
Override the speed governor? No problem! The “always connected” ECU will send your make, model, license and destination (don’t forget you have to tell it where you’re going since you can’t actually drive it) to Smokey so he can be waiting for you when you get there.
Yeah, but AVs would free you to have sex enroute, with or without others.
The Ultimate Stick-Shift!
CITIZEN MY SENSORS ARE REPORTING TWO PASSENGERS IN THE BACK SEAT, BUT THE SEAT BELTS ARE NOT FASTENED.
PLEASE CONNECT YOUR SEAT BELTS.
PLEASE CONNECT YOUR SEAT BELTS.
PLEASE CONNECT YOUR SEAT BELTS.
(click seat belts together to shut off the voice)
……
CITIZEN MY SENSORS ARE REPORTING SHIFTING MOVEMENT IN THE BACK SEAT THAT WOULD NOT BE POSSIBLE IF ALL PASSENGERS WERE PROPERLY WEARING THEIR SEAT BELTS.
PLEASE WEAR YOUR SEAT BELTS PROPERLY. PRESS THE HELP BUTTON ON THE POP UP SCREEN FOR A VIDEO TUTORIAL SHOWING HOW TO PROPERLY DON YOUR SEAT BELT. FAILURE TO WEAR A SEAT BELT PROPERLY WILL RESULT IN YOUR VEHICLE REMOVING ITSELF FROM TRAFFIC AND COMING TO A COMPLETE STOP. CIVIL AUTHORITIES MAY ALSO BE CONTACTED.
PLEASE WEAR YOUR SEAT BELTS PROPERLY. PRESS THE HELP BUTTON ON THE POP UP SCREEN FOR A VIDEO TUTORIAL SHOWING HOW TO PROPERLY DON YOUR SEAT BELT. FAILURE TO WEAR A SEAT BELT PROPERLY WILL RESULT IN YOUR VEHICLE REMOVING ITSELF FROM TRAFFIC AND COMING TO A COMPLETE STOP. CIVIL AUTHORITIES MAY ALSO BE CONTACTED.
PLEASE WEAR YOUR SEAT BELTS PROPERLY. PRESS THE HELP BUTTON ON THE POP UP SCREEN FOR A VIDEO TUTORIAL SHOWING HOW TO PROPERLY DON YOUR SEAT BELT. FAILURE TO WEAR A SEAT BELT PROPERLY WILL RESULT IN YOUR VEHICLE REMOVING ITSELF FROM TRAFFIC AND COMING TO A COMPLETE STOP. CIVIL AUTHORITIES MAY ALSO BE CONTACTED.
Even worse, they’ll probably go at the speed deemed safe by your insurance company for the conditions.
Worse?
Oh, yeah… eventually we’d wear it out, yeah.
kvndoom, don’t forget you had to sign a software license when you bought the car. The electronic governor and ECU don’t belong to you. Modify it, and you can expect to hear from some OEM lawyers.
Seems like a similar setup to what Mazda is doing in the new CX-9 2.5T. Not being an engineer, not sure what the distinctions are.