some incredible bsfc numbers...

[mobile_bob]

a member in good standing over on fieldlines.com has reported some really incredible fuel
consumption numbers with a small air cooled generator.

http://www.fieldlines.com/index.php/topic,147744.0.html

i have responded with a question to see if we can verify this,
it is so far outside the norm for this class of generator, that i thought it ought to be checked out
and discussed.

anyone have any experience with one of these units?

bob g

[Tom Reed]

Here's a link to a spec sheet for that engine. I can't read what ever language it's in.



These engines are available and quite pricy. Subaru makes a diesel version of an Outback that's available in Australia. I wonder if they get similar economy.

[mobile_bob]

Thanks Tom

i am going to take from the chart that the engine is rated at ~300gr/kw/hr at full rated load and 3600rpm... that is about what one would expect, pretty decent but not spectacular.

i got a rather rude comment back from the OP about my questioning his numbers, at least that is
the way i took it when presented with his trying to school me in "diesel 101"... that i can deal with.

i went back at him again, and will see how it pan's out.  my point was not to call him out as full of crap, but to determine the validity of the claim.  if he had something that was doing even close to what was reported my thinking was we ought to know about it!

unless he can support the claim with some good rational or numbers, my thinking is to just dismiss it as another "my car has 750hp" or "my chevy is faster than your ford" or (my favorite)
"my daddy can beat up your daddy"

lol
bob g

[mobile_bob]

well it looks like he has no interest in responding to my questions or in rerunning the test
on the generator to verify his claims

so i guess we can write this one off to some sort of fault in testing

bob g

[glort]

I tried to register for the Fieldlines site some weeks ago. Guess I'm not worthy of being there as my registration still hasn't gone through.

I had a look at the thread and can only say I think you gave the guy a bit too much credit. Reading his responses to you, Frankly he seems like an arse.

The engine on that generator looks like the Chinese Verticals I have a couple of. It' looks nothing like the Hatz 1B30 I also have. In the first Vid the thing does indeed sound like a  Hatz. They have a very different sound to the Chinese engines. In the 2nd and 3rd Vid, it sounds exactly like a chinese engine. They have the charismatic diesel knock/ rattle under acceleration or deceleration and I can clearly hear it in the last vids.

I have done no meaningful fuel/ efficiency tests but my gut feeling is the Hatz engines are a bit more efficient than the chinese ones.
They sure as hell run a lot smoother and quieter that's for sure.
The fuel pump and various components are also different from the Hatz to the chinese engines. Even the chinese Verticals and horizontals are very similar in the pump, injector and governor layout, The Hatz has a totally different system.

As for the super efficiency of the Subaru generator, I think the design and operating speed pretty much put pay to any great difference's there.

[Ronmar]

It seems that just about every one of these we have "Discussed" over the past few years, the author could turn a wrench, but was completely clueless when measuring the ACTUAL load applied.  IMO, that is probably where the outstanding fuel consumption figures are comming from...   "So what voltage and current have you measured under load?"  I don't know, but but but I have four 1KW heaters plugged into it!"... 

[mobile_bob]

i think Ron has it right!  he would not be the first that got bit with his load bank

that is precisely why i quit trying to maintain my load banks integrity and just went with
a known quality watt/hr meter... no having to account for power factor, no having to worry about one of my heaters shutting down mid test, or a draft blowing in and cooling one or more of them down... none of that... the meter simply keeps track of the actual watt/hrs delivered to the load no matter how unstable it might be.

i don't think that fellow would last long around here, not that we are a tough bunch but we do ask questions and we do expect answers or at least we expect an honest effort.

the way i figure it, if i met with such obstinence , what might a newbie think his chances would be asking questions?   i don't think it makes the place very easy for folks trying to learn.

that is kind of sad really, fieldlines has been around for a very long time now, and in my opinion is the defacto goto forum for diy windpower, or at least it used to be.

sure is much more pleasurable discussing things with you guys!  even arguing points with guyfawlks was much more productive if not less tedious.

bob g

[Henry W]

Oh boy, For some reason I just got a flashback of the name Spencer. I think the guy has convinced himself that he has the worlds most fuel effecent small diesel engine. He mentioned that he got the Robin DY27 tweaked for peak torque rise. That is false. That engine is running at 3600 RPM. He mentioned he adjusted the injector pressure to factory setting. In everythig I looked at, 2500 RPM is peak torque. At 3600 RPM these engines are asthmatic and no matter what you do will not change fuel comsumption numbers much. At rated output the engine consumes just under 300 g/kW-h.

The Launtop LA178 and LA178FA posts better numbers than the Robin DY27. The Robin DY27 engine is not anything special. They are in the same catergory as the Changfa, Launtop, Yanmar and Kohler/Lambardini engines. I would personaly pick a Kohler/Lambardini or Launtop over that engine. At least you can get parts.

If you want to get into higher quality air cooled diesels than look at some of the Farymann air cooled diesel engines. http://www.farymann.com/engines.php?page=15d-18d
At least they can be rebuilt and have a true spin on oil filter. These engines will run much longer than the Robin DY27. I seen the Farymann engines cheap on Ebay.

You want to talk about a small air cooled diesel engine with good numbers?
Than look at this: http://www.farymann.com/engines.php?page=43f

Henry

[SteveU.]

Hi All
Well since you fellows ARE talking about small aircooled diesels I had a woodgassing fellow inquire to me about these Chinese aircooled V-Twins:

http://www.punsunengines.com/bbx/322328-322328.html?id=124988pid=207978

Your thoughts?
They say US EPA certified.

Regards
Steve Unruh

[mobile_bob]

Steve

i can't get the link to load this evening, but if it is the engine i am thinking of, they appear
to be very well engineered engine's

last i heard however they are relatively expensive which might be reduced if there were enough demand for them to get a container full of them.

it looks like the link just loaded! and it appears to be the same engine i was thinking of.

they certainly look like they are made to fit just about every application appropriate for their output too. also appear to have a full pressure and filtered lube system?

epa certified would sure help a lot getting them into this country.

now if we could just get them to produce a water cooled single that is epa certified

bob g

[SteveU.]

Thanks for the feed back on this BobG.
On the engines this was my opinion also. Good for High Speed 3000-3600 RPM spec diesel/bio-diesel fuel usage.
Henry's comment about naturally aspirated diesels as all "asthmatic" at these high RPM's and the g/kWh numbers on the FaryMann site seem to confirm that if you insist on these RPM's you will sacrifice fuel effiency. Want the fuel efficiency, then for heavy fuel oil fuels you need the better smaller bore/longer stroke versions set up for 2200-2600 RPM power curves. Most get pixilated on just engine RPM and fuels BTU modeling and do not even realize how the other engine internal ratios of bore versus stroke, rod length to crank throw, actual piston speeds and combuston chamber shaping plays into all of this for a specific fuel type optimizing.

Yep. ~$1000. USD expensive for these, one at a time, with comparable one-off freight costs. Container loads would have the first at least halved, and get the shipping down to ~10% of the landed engine unit costs per unit.

This fellow asking me IS based out of a warmer equatorial country. CHP is not an make or break issue in his market area. He is however a woodgas fueler still stuck on the Internet myth of just blending in woodgas to diesel pilot ignition as a given. It is not a given. It is possible only with some diesels with a lot of work then on two fuel side systems and now an added air side control and will make them then into very much compromised diesels now as suction engines no longer then capable of efficient diesel fuel operating.
Yes I said it - ANOTHER INTERNET OFTEN REPEATED MYTH.
All who have actually having done duel deisel/woodgas fueled, soon quit, and go with either dedicated purpose built spark igntion engines; OR, compression reduce down to below 15/1 and then spark convert  the original diesel based engine as a single woodgas fueled engine.
Here you DO want big bore/ short stoke ratios with slower range piston speeds to best match the compressed flame front of the composite woodgases fuel mix.
Engine power equivencies experiences is saying now for the best woodgas fuel conversion efficiencies you also want flat topped pistons and actual true valve angled  in the cylinder head hemi combustion chambers. Woodfuel gases wants to be handled gently with only moderate turbulances.
Exact opposite of the best know diesel fuel engine practices.

Regards
Steve Unruh

[mobile_bob]

well it appears the forum has resolved the issue by deleting the topic

sad how things can spin out of control so quickly when members refuse to communicate
civilly with one another.

bob g

[ChrisOlson]

Actually, I'm the guy that's got the Robin RGD3300 generator, and I've been on this forum for quite some time, mostly reading and not posting.  So I'll clarify some things.

Firstly, I did not report any BFSC numbers.  Those are derived on a dyno with fuel flow equipment and corrections to standard conditions.  I don't know how it got assumed that it has anything to do with BSFC.  I plan on using the generator for prime power on the AC1 input of our XW inverter to provide power on bad RE days for our off-grid power system.  I was curious to find out how long it's going to run doing the intended job on a tank of fuel.  I set the Generator Support level to 3.05 kVA on the AC2 input of the inverter and it burned 795cc out of my graduated 1 liter container in one hour.

It was merely a simple fuel consumption test to determine run time without burning a whole tank of fuel to do it.

The results of my fuel consumption test with the generator doing its intended job somehow got misconstrued into something else.

Secondly, the Robin DY27 is not a Chinese engine.  It is built by Fuji Heavy Industries in Tokyo Japan.  They were originally called Wisconsin-Robin, then just Robin, and now Subaru-Robin.  The engine has not been sold in the US since late 2004 due to emission requirements.

Thirdly, I set the smoke screw for peak torque rise during overload so the generator loses no more than 2 Hz with a 4.0 kVA surge load, and 1 Hz with 3.5 kVA overload.  This is to prevent the inverter from disqualifying the generator during surge and the two seconds it takes the XW inverter to support it.  This has somehow been misconstrued into someone saying that I said I set it for peak torque on a dyno curve.  I did not.  This is a generator set that will be operated in a Generator Support mode (actually Grid Support on AC1), and this type of use requires a very stable generator to prevent the inverter from spitting it off.

When you get people that tend to take things and run with them, without fully understanding the purpose or methodology you get things blown all out of proportion.  And that's exactly what happened when Bob G started ranting and raving about BSFC on the Fieldlines forum.  I repeatedly told him this has NOTHING to do with BSFC, but to no avail.  I finally requested that the moderators remove the thread because of Bob G's rants that took up over half it and totally sidetracked the thread from its intended use for this generator.

That's all.
--
Chris

[Henry W]

Chris,

I know that Robin DY27 for years. I know it is built by Fuji. That engine cannot get the fuel consumption numbers that you posted.  Especialy running at 3600 RPM's. I did read your numbers myself. It just won't happen. That engine falls in the same catregory as the air cooled engines I posted earlier. It is no special engine and the fuel consumption numbers of the Robin engine fall in line with all the ones I listed except for the Farymann 43F. Now that is an exceptional engine with great fuel consumption numbers. When we see numbers posted that are way out of the norm it raises flags and in turn people will want to see proof.

Bob G. did the proper thing by wanting to see the proof since your numbers were way out of line. Bob G. is respected in many fourms because of the years of his hard work and dedication in the power and generation field. You have posted a topic with numbers and people here know that those numbers are impossible to reach no matter what you do to that engine.

The way I see this topic being defused for you is to take the time to get accurate numbers and than post. We have a rough idea where the numbers will be. Did it ever occurr to you that you made a mistake with your numbers?  We all make mistakes at times and there is no shame to admit to a mistake.

Henry

[ChrisOlson]

The way I see this topic being defused for you is to take the time to get accurate numbers and than post.

Henry, basically I will tell you the same thing I told Bob G - this project is not about fuel consumption.  I just needed to establish a run time on a tank of fuel to determine if I was going to bother with an external fuel tank when I install it in the new power house I am building for both it and my Honda EM4000SX standby generator.

You guys on this forum are hung up on this topic of fuel consumption, while I am not.  But I guarantee you that the little thing burned 795cc of fuel in one hour out of my 1 liter graduated fuel tube during the test.  I don't care if people want to believe it or not.  That's what it did.  I did not measure the kWh produced by it during the run or anything.  I only wanted to establish one baseline - how many hours will the unit run on one tank of fuel doing the job I will be using it for.

So for somebody to suddenly apply BSFC values to a test where the load on the engine was not even measured is beyond common sense.  All I did was set the Generator Support level to 3.05 kVA in my XW inverter to test it.  I don't know if you're familiar with the XW inverter or not, but it loads the generator to 80% of the AC1/AC2 breaker size that you have entered with the charger (assuming the bank needs charging) and leaves the last 20% for loads.  If loads increase it dials the charger back to keep the generator at the desired load.  If loads increase beyond what the generator can produce the inverter helps the generator in Support Mode.

How anybody could construe BSFC numbers out of this is beyond my comprehension.  I worked for Cummins for 19 years as a mechanical engineer - I was on the team that developed the B-series engine in a joint effort with what was then J.I. Case.  I have established dyno curves for many, many engines in my career, including BSFC testing on dynamometers, and I will tell you straight up that anybody that starts spouting BSFC numbers from a load test on a generator are so far out on the limb that it's about to break off.  You can try to establish gallons or liters per kWh, or similar, with a generator set.  But not brake fuel consumption with such a test.  And anybody that THINKS they can, does not know what they are doing.
--
Chris