Jinx

I don't always understand what you post, but I always appreciate it.

That piston is quite the dish.

I Bin Therbefor

If you take the single cylinder displacement of the test engine and multiply by 8 you get 5.36lt. I really, really hope that ISN'T the displacement of the new Gen V engine. But why build a single cylinder test engine if it wasn't?

DREAMERAK

It's probably just one the Gen V engine sizes.

I Bin Therbefor

In reading the article again, it does specifically mention pick up trucks and lower rev engines.

At least I hope you are right.

Jinx

If it has a torque curve like today's LS3, I don't care what volume the pistons displace.

LS1LT1

Afterall, there currently IS a 5.3L truck engine.

Runge_Kutta

Whether the Gen V is a 2V or 3V design, the intake ports can be substantially redesigned relative the the port injected Gen IV engines. There's got to be some available benefit from that change.

This stuff is quite technical. Still, you don't need to be a combustion specialist to get a few ideas from this. The second link is probably the most interesting. Page 22 clearly has a 2V engine.

http://web.iitd.ac.in/~pmvs/ICengines/paper12.pdf

http://www.google.com/url?sa=t&rct=j...3mjhBNBMvC7IZQ

http://www.google.com/url?sa=t&rct=j...2p81bxBCcMXxUQ

"We estimate that these technologies allow for a 9% improvement in fuel efficiency from current engines,"

235265283...

Runge Kutta:

Please indulge me the following opinion (especially since it's not like opinions haven't ever appeared in this forum before):

Any engine technology (such as most of those referenced in your posts) that isn't compatible with use of a three-way catalyst for exhaust emissions control won't be used on the C7, Gen IV engine, or hardly any other GM products over the next few years.

My interpretation is that much if not most of the very interesting technology described in the documents you cite above and your other two posts to this thread involve various DI stratified charge systems that aren't net stoichiometric A/F at all operating conditions and are therefore incompatible with a TWC. Please correct me if I've misinterpreted these documents.

I've witnessed R&D and limited applications of DI SC and its variations since the Texaco work in the 1960s. During that time, I watched the TWC (with EFI, O2 sensor, and closed-loop control) abruptly revolutionize US light-duty vehicle technology with relatively little fanfare. So please understand (but don't necessarily agree with) my skepticism about non-stoichiometric DI SC technologies, lean-NOx catalysts, etc.

I Bin Therbefor

I offer my wife as test driver for the Gen V engine. She as the innate ability to make any technology fail. After having done so, she then will announce, "Well, why doesn't it work?"

GM is taking a heck of a chance changing all the V8s to the new DI, whatever it is. IMO they would have been smarter to make a special run of engines for the C6 Corvette to see how they will work in the hands of John and & Jane Q public.

BlueOx

So what other engines have they done testing with in the hands of the public?

SanDiegoBert

I remember standing in a shopping center parking lot in La Mesa, CA, when the car next to me started up: It was a turbine-powered Oldsmobile Toronado, one of the few released to the general public.

Sounded just like a J-79 spooling up. Weird, to say the least. It happened decades ago, I don't remember the year, sorry.

I Bin Therbefor

Several mfgs introduce small runs of new engines in current models as a way of getting some real life experience. Seldom do they make a major vehicle and running gear change together. The C5 did that. It was a real gamble for GM that paid off big time. For that matter, GM has done the same, introducing the high tech V6 on models that had small production runs as a way of getting real life experience.

The Corvette has often been presented as GM's way of introducing new technology and getting some real life experience. The use of carbon fiber hood and other body parts comes to mind.

My point is that DI and a new combustion system is not a straight forward mechanical refinement of a current design. GM is placing all their small block V8 bets on this one without a small production run to get real life experience. I hope it pays off big time because the down side is really steep.

BlueOx

I have to imagine there have been a number of mules out there running whatever drive train we will see for some time now. I also imagine they are traveling among us on the highways and byways of America.

GM has had 4 and 6 cyl. DI engines out there for years.

Runge_Kutta

I have no idea what GM plans to do with the Gen-V family of engines. However, thermal efficiency in these engines needs to get much better than with the current port-injection Gen IV engines. Some of those documents point to the way designs must head if efficiencies are going to get better. Implicit in what you have written is that aftertreatment technologies are not also being studied to deal with SIDI engines. Again, I am no expert on all of this but if you look at this patent search, you could easily get the impression that GM has been working hard to manage emissions, gaseous and particulate:

http://www.freepatentsonline.com/res...ch=top&search=

I think it is interesting to look at this Gen V fuel injector:

http://www.insideline.com/chevrolet/...all-block.html

and compare that with the picture of an injector spray on page 22 of the paper by Drake and Haworth. Also, given that GM has effectively stated that efficiencies will rise 9%, How aggressive does technologies have to get for this to be possible?

Incidentally, I believe this is the most recent patent concerning the 3V engine that may have just gotten killed at GM:

http://www.freepatentsonline.com/7523729.pdf
http://www.freepatentsonline.com/6505589.pdf

blackcorvette06

theres a pic of the gen5 on this site ...ALSO on motortrend
http://www.bizjournals.com/buffalo/p...llery&img_no=0

Runge_Kutta

Nice!!

It does not look like a 3V engine. The 3V engine heads are much bigger than the 2V heads and I think the picture is showing familiar head dimensions.

Are these side or top mounted fuel injectors relative to the combustion chamber?

chaase

Where does GM get the CTS motor then? The CTS has had a DI for quite some time. If they are building the Cadillac motor, then they are quite familiar with DI.

Jinx

And it may be that Corvette runs the new smallblock alone for a year before it shows up in pickup trucks or Camaros.

Or maybe they've been running DI V8s in pickup trucks of certain fleet customers on the QT.

Or maybe their years of volume production of DI fours and sixes is enough to go right to volume production on the eight.

.Jinx

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Black:

Thanks, excellent find and post! I went to Motor Trend site and couldn't find what you refer to. Can you provide a link? I did, however, find a few other news items re the new V-8 to be manufactured at the Tanowanda Plant; one refered to the new Silverado engine, but I'm sure the C7 engine will be a variation of the Silverado V-8 (or visa-versa, as some of you will probably insist).

Based on a quick look at the photo, I'm not sure of everything I'm seeing. Quick onsrevations/speculations:

Doesn't look like OHCs to me.

What the heck are those round tubular receptacle-looking things in the exhaust manifold that look like the're pointing into the ports? These can't possibly be injectors, can they?

And those "bumps" that are above or part of the valve cover? Each one looks to have a different size and shape. I don't think these are coils? Could these possibly be part of some VVT mechanism?

Jinx

Looks like an OHV to me. The head castings don't look big enough to be DOHC. Definitely some weird lumps on top of the valve covers, though.