Alright!!!... Paydirt!!!
This is the kind of stuff I've been wanting to hear!
I knew someone out there had to have some of their old college engineering textbooks still lying around...


besserheimerpha, Thanks for the excellent info you dug up... but don't hurt your noggin' over this stuff.. I'm already gonna' have to "ease" into what you've posted...
Enjoy your weekend... I'll check back after I too slay a few brown bottles this weekend.

Rusty, I too am interested in those really cool examples of super high efficiency marine diesels.
Direct drive and NO clutch to burn out!!! heh heh

Dieseldude, Now since I have a Dodge diesel truck with 35gallons of fresh fuel onboard, I have a ready, mobile supply of fuel for both my transportation, RV camping and powering my home after a hurricane!
Presently, I have a dual-fuel(LPG/gasoline) ONAN 5.0CCK generator, but now with no large stash of fuel and no natural gas in my subdivision.
While I had my old GMC PU, I had two 16 gal tanks of UL onboard that I could connect to my Onan for fuel.
I do not like the idea of storing 55gal barrels of UL in a residential garage. (very illegal too!)
Now with DIESEL,... I may decide to fudge a bit
I want a simple, highly reliable, Kubota powered, direct coupled, 1800rpm, 6 to 8kw generator that I don't have to pour a 10ton, 8' deep concrete foundation for.
To that end, I'm working on getting my hands a Kubota 3cyl 905-G powered 6KW portable Light-Tower rig from a guy that bought two of them at an auction and "supposedly" wants to sell one..

Later,
Keith

 

The formula would hold until you begin suffering effects simply from the small number of molecules involved and there's always the uncertainty principle to contend with.

On the Holset site there are some interesting articles about recovering some of the waste heat post turbo and running another turbine directly coupled to the output shaft of the engine. If I remember correctly a 4% gain in efficiency is achieved.

I wonder if wrapping the exhaust manifold with insulation would help things?

Edwin

 

Yep, some of the marine propulsion diesels are turbocompounded - that is, they have a turbine rotor downstream of the turbocharger(s) that is coupled back into the engine output. This captures some of the residual energy remaining in the exhaust stream.

Rusty

 

I have a Generac 6500 contractor/construction grade that works very well but it really screams when it unloads. It kept us going for over 13 days when Isabell came through and destroyed the state a few years back. Never missed a beat and ran the water heater and everything that needed to be ran with no problems at all. I only ran it about eight hours a day though, some in the morning and some in the evening and didn't lose anything. Like you though, I don't like keeping enough fuel in the shed to equal the power of a small nuke and want to go safer with the diesel thing. There is an outfit in the north east that sells them on the frame ready to go for about $4500 but I can't remember what the site was. I am also working with a guy around here that is kind of a wheeler dealer and had found a load of military surplus diesels for sale a while back. Hoping to hear from him soon.

 

standby power

https://www.dieseltruckresource.com/...cat/500/page/1

what i use in a pinch

 

Sorry if I just ended up confusing everyone. I'm an engineer but I'm not in the automotive/diesel industries (I am a test engineer for a company that makes control valves). I just happened to remember that my ME Handbook had a chapter on IC Engines, and thought it might have some info. My knowledge is more in the fluid dynamics and machine design areas, as that's what I work with on a daily basis. I tried to forget all the thermo/heat transfer classes I had to go through. I'm still kind of a youngin' too, as I'm only 24, 1 year out of college, and still trying to gain practical experience beyond my book learnin'. Till then I'll just try and help out where I can and ask questions when I can't. Have a good weekend.

 

Check out Marks' Standard Handbook for Mechanical Engineers. There is a good section in there on enginees.

 

Nope, yours was an excellent post. Thanks for contributing.

Rusty

 

As I recall from my motorcycling days 'volumetric efficiency' favors more cylinders. This was used by Honda in early years for GP bikes, where they ended up with a 6 cyl 250cc bike that had a lot of gears. Bikes like that resulted in limitations on the number of cylinders. Look at WWII piston powered aircraft, where lots of cylinders were common, either in the inline or radial configuration. The M60 tanks in our battalion had V12 diesels. Closer to home look at the gas V10 offerings in some pickups, which put out decent torque as well as HP.

The advantage of the inline 6 in diesels seems to be the ability to get good, low cost balancing, a lighter weight block for a given level of stiffness, and good torque for a given displacement. In other threads where we looked at HP vs torque it's surprising how little the HP changes in light thru heavy duty engines even though the displacement changes a lot, but torque changes dramatically. A friend noted that he had an older 20k lb GVWR Chevy truck with a 350 cu in gas engine that showed the difference between higher HP/lower torque vs higher torque/lower HP trying to do the same work; it didn't get much above 55 mph, you were always revving it hard, it was on it's 2nd engine at about 80k miles, but it worked :^)

 

No, you didn't confuse us... Thats exactly the quality info I was hoping to dig up... Thanks for posting it. I didn't get a chance to chew on it Friday as I had a rather frustrating week and that was put low on the priority list this weekend.. (R&R=1st pri) Unfortunately, today has started out about the same as last week.

Hmmm... Control valve manufacturer, Iowa... I'll make a guess, Marshaltown Ia. and you probably work for Fisher? We have many of those green valves in our plant.


K.

 

RustyJC, How do they couple those turbocompound units back into the engine? Seems that the rotational variations of an engine would play heck with that high ratio, high speed gear train. Do they have some kind of torsional "spring plate" like our clutches have to take some of the shock loading out of the torque vibrations?

NORM, your picture reminds me of a fellow ham radio operator here in town. Years ago, he picked up an old oilfield-built ~30-40kw diesel gen. It has an old Detroit 4-71 direct coupled to an alternator of unknown pedigree. (MUCH more engine than the gen could ever use.)
He also keeps it in his garage on a trailer.
We've used it for Ham Radio "field day" exercises for many years powering portable communication trailers with A/C units, blowers, Ham radio's, lights and big floodlights.
It BARELY uses fuel compared to the old WWII gasoline unit we used to use.
But that old Detroit would slobber oil like no ones business!!! With as much load as we could muster, the exhaust was still ALMOST cool enough to hold your hand in it... You didn't walk downwind of the exhaust with a clean shirt on!!!
We'd shut it down and check the fuel but would have to fill it back up with oil.
It's amazing how quiet things got with that noisy thing shut down!
After site tear down, there was no mistaking the area where the generator sat.

Dieseldude: I was scrutinizing e-bay for some time seeing some good surplus units go for exorbitant prices! I think I know which kind of unenclosed, bare units you are talking about.
They sold mostly 1800rpm Lombardini/Deutz DI engined units, but I am stubborn and I want to stick with a Kubota 3-banger turning 1800rpm. Kubota's are still indirect inj and I think the TIER-III regs may be forcing most OEM's to go to DI engines for their products.

Fronty: Unfortunately, I don't have access to many ME textbooks down here in the bottom of the world. Hopefully someone else does and can look this up for me..
Is it possible that this "effect" may have had to do with the thermal conductivity of the smaller amount of compressed air losing its heat to the surrounding cylinder faster than a larger scale engine? I dunno'...


THanks
K.

 

Typically, by reduction gears and a fluid coupling. HERE is Scania's approach for truck engines explained. It's actually quite relevent to this forum since it was developed with Holset, Cummins' turbomachinery division.

Rusty

 

COOL! I wondered how they would keep from wrecking the gear train if the engine missed on one cylinder and all that sudden deceleration torque has to go be dealt with.
K.