FOOD FOR CRITICAL THOUGHT IS ALL AROUND US.
A look at a newer engine from China now on the assembly line.
Two Cylinder Water Cooled Domestic Engine
I have been getting calls from a certain off girder who has become obsessed with the idea of fitting a large flywheel to a small gas engine and optimizing it for about 250-500 watts of slower speed output. Is he right to consider this machine? Maybe we discuss the merits here?
As much as slow speeders might be attracted to the idea, should we willy-nilly make one before we make use of paper and pencil, and apply a little critical thought, maybe explore what has been common knowledge since Diesel’s engine first?
Isn’t this everyone’s goal? To get more work done for less expense? We don’t all have 300 days a year of sunshine, hydro, magic beans, nor do we all believe that the present politician will save us all.. if only we vote to take from the guy who has a dollar more and share with us. Of course fools will always vote for such a thing, and soon they find they are among the rich guys according to the measure. Should anyone have a house before all have an apartment? Remember, they say..you didn’t build it yourself.. no matter what you built, no matter how modest, or how meek you might be.
That idea of adding mass to the flywheel in order to make more efficient use of the energy. Is that the way the world is going, and why not? There is a documented case of an off grider using a small stock honda OHV horizontal shaft engine for 10,000 real hours of off grid battery charging, yes, he did use an inefficient alternator designed for an auto, but most of us with real experience know that 10,000 hours of running is a LOT of service, about three times what the majority of commercial users demand of a small engine.
But the idea of adding a flywheel to this design and running slower? Consider the stock crank pin, and that short stroke, the piston speed all too slow, and this gases burning and unable to push the piston forward at a reasonable speed, the gases attempting to cut their way through the ring gap, and the load applied to the ring lands, and what about the load on the pin, and the crank pin bush itself? Yes, it does seem that slow speed engine have long strokes, and for good reason I think.
We also need consider how popular those new inverter generators are. I remember this catching Professor Vijay Modi’s attention long ago, (Engineering Department Columbia) the idea of running variable speed, and producing the power required, same as large grids do, we meet the demand, and we might find a use for super caps or batteries in our scheme to produce a dead silent power, or a way of utilizing other forms of energy into our system.. like PV or micro hydro.
I favor a power plant that can handle multiple inputs, and I see no reason we can’t design a simple interface and switch out or divert that source to perform other work when it overwhelms our storage bank.. Some systems do that today..
Let’s look at China as an example, they are no wiser than anyone else, they make tons of mistakes, and those who are in office live in fear every day of failing the people and being moved out of office. They rely on millions of small engines to pump water, grind grain, power fishing boats and more. Part of critical thought is to ask.. what are they doing in the small engine industry for domestic consumption? Are they gearing up to make a move to lighter and higher speed engines, or do they build them only for the rest of the world?
A key may be seen in the engine that Lee took on the factory floor in China yesterday,and maybe I remind you that Lee is a DIYer first, and he’s spending time with David this week…. they are attempting to find the golden nuggets for themselves and other DIYers.
Do look at that flywheel, and how it’s been adapted for the domestic drive system. Yes, that’s a popular Asian Standard,and it’s there only because it will be deployed into the Asian market. I think there’s a good chance these engines WILL replace the old and expensive to move cast iron engines. We need recognize that the weight advantage will save a great deal of fuel over the lifetime of the engine in a two-wheel tractor, or small cart used to take produce or similar out of the field towards the collection or distribution point.
As you might know, Lee and David have earned my trust, they believe in delivering the highest quality they can find. They know there’s all kinds of junk to be had, and this reminds me.. more news from Noel Douglas and the ultimate off grid sight.. an Island Paradise. Noel imported some 1115s and found they ran for 1000 hours before they came apart. Yes, he bought the version designed to sell, not to go the long run. We Western minds seem unable to comprehend that not all engines are created equal.. Yes, I’ll tell that story, and maybe you subscribe here so you don’t miss it..
Thank you for the pictures Lee, I will share more.. I wish I could be with you and David this week. Readers, do note, this engine is on the assembly line, that means the engine IS being built in quantity.
One thing we can expect, this water cooled twin solves some problems for the ‘Cult Like Diesel Motorcycle movement, they will experiment with it soon as they get their hands on it! If you haven’t done a few google searches, you’re missing some good entertainment and perhaps a learning experience. The past air cooled models need the fan, taking it off looks cool, but the fins are not adequate and over heating happens in a hurry. NO we need to see if this engine was designed with the care the Japanese generally apply, and if the quality of parts, and assembly is generally acceptable as well.
Oh… and a reward for those who read this last line.. this little engine IS EPA certified..
GB
when are you gonna order some of those engines?
i think i would like to play with one, might make a nice alternative
cogen unit.
bob g
Kurt, Nate, Bob,
I think Lee and David will get more detail about this engine, according to what Lee learned knowing the Mother language… there were two Japanese engineers and some guy fron Princeton who lead the engineering effort. Lee says one assembly line they were watching, test run the engines twice, they are getting serious about Quality, but the mainland is still a little like the wild west, there’s still stuff to buy that is made to a much lower standard. Noel is no push over, but his supplier sent him a far lesser engine, and as I promised, I will write a short article about that. Later.. There’s still a lot to share from Lee’s trip. Part of the problem in China is those who counterfit.. slapping a name on something is easy, and would you know the difference?
Interesting Engine! Any details?
details please
Gents,
the model designation is EV80. 80mm bore 79mm stroke. rated at 14hp@3600 rpm. max torque is 43Nm@2100 rpm. total displacement is 0.794 lit. weight is 58Kg
more details and pics will be posted by George.
unit is made by Changchai; the first diesel maker in China since 1913. the Chinese National Diesel Engine Test Lab is incidentally situated inside Changchai factory complex in Changzhou, a 2.5 hours drive north west from Shanghai.
Changchai literally means “diesel in eternity…..”.
Thanks Lee,
I really appreciate your efforts to share with us, and I have more to put up.
I want to mention that I have been watching the CF186 series, and I have a post here on them. The first units I saw have castings that look like late sixties work from Japan or better.. that was plenty good by my standards. The later pictures you sent of this EV80 look as if the Mainland has purchased the very latest casting technology! Instead of a lot of pictures, maybe I put up one in higher resolution. Stay tuned, Lee has sent enough for several posts.
so do I have this right 9.45kw @2100rpms?
EV80 Diesel Engine Specifications
Type 2 cylinder?V type?water cooling?4-Stroke?Swirl combustion chamber
Bore x Stroke (mm) 80×79
Displacement(L) 0.794
Compression ratio 23
Rated Output/Speed (kW/r/min) 12/3000 14/3600
Lubrication system Combined pressure and splash
Starting method Electric Starting
Direction of rotation
(view from output shaft) Counter clockwise
Average effective pressure (kPa) 604/3000?588/3600
Injection advance angle 18.5°±0.1°
Valve timing Intake valve Top dead center front 22°turn on?Bottom dead center rear 56° turn off
Exhaust valve Bottom dead center front 61° turn on?Top dead center rear 26°turn off
Lubrication capacity L 2.27
Cooling water capacity L 2.9
Cooling water temperature °C ?95?alarm excess 105
Exhaust temperature °C ?500
Oil temperature °C ?110
Piston average speed m/s 7.9/3000?9.48/3600
Fuel consumption/speed
?g/kW.h?/r/min 285/3000 297/3600
Lubrication grade SAE 10W?30?SAE 20W?40
or L?ECD grade
Oil pressure MPa 0.2-0.6?alarm within 0.06±0.01
Starting motor capacity (V?kW) 12V 1.4kW
Charging generator capacity
( V?A? 12V 20A
Storage battery capacity(V?AH) 12V 60AH
Overall dimension?L×B×H? (mm) 650×486×528
Net weight (kg) 58
any news on this little gem?
Hi Kurt, Friend, DIYer.. Son Wah Lee said he’d buy one and play with it a bit. I assume he will report on the performance after he’s had a chance to gain some hands on. We Americans have the EPA to deal with, but there are now other concerns, we’ve seen the price of PV panels dip below $1 a watt, and still some people in our community too thrifty to buy. Considering there are engines that I could once buy for $200, that now cost $850 just 12 years later.. I’d say we better consider buying our hardware now before WE Americans allow further destruction of >our< money. No one has a crystal ball, but if a guy needs a new roof on the house, or even a new car, this might be the time to convert savings into the things a guy really needs. Measured in Dollars, you may never see this much buying power again. The Fed loves to counterfit on our behalf, and if we take a minute to see how it works, they are simply making withdrawls on any savings we were stupid enough to have WHEN they print more money.
oh my heck! its a diesel!! wow, how did i miss that?
i assumed it was a gas engine from the introduction piece
now i am really interested in the engine knowing it is a diesel.
would like to know an approx cost and about when it might be available in this country.
bob g
Lee sent me an EPA certification for this engine, but we might find it sold under a big name here for a big price.. who knows yet! Lee did order one to experiment with back home, and Lee and David will look into costs and export to our community. What we know is cost is large for one each, we really need a container load to make it worth while.. BUT first.. a smart man gets run and runs the crap out of it! We best talk Noel into buying one 🙂
G
can we get a manual for one of them? having one would go a long way to see how they are made, what is used internally, and such.
heck i would pay 20 bucks for a manual with parts breakdown in it, like the ones sent out with the 195’s, 1100’s and 1115’s
i am thinking it could be slowed down to 1800rpm operation and still do its thing, but it really depends on what is inside these critters, and whether or not we can adjust the injection timing, what the governors look like and all that.
if it could get down to 1800rpm and run there stable, maybe one could get 3-4kwe output, which would be very useful for me and i would suspect much of the microcogen community.
and if it will run at that rpm there will be those that will get it down to sub 1000rpm and get it to make 1-2kwe, just hide and watch!
looks like something that would be interesting to work with, and it comes at a perfect time, when there is really nothing in its class that is epa approved that doesn’t cost a kings ransom at least that is water cooled.
bob g
Speaking of fuel to kwhr ratios.
http://windsine.org/?act=blog&f=view&id=16
Notice his diesel gal/kwh is .121. This is going from a listeroid to a DIY axial flux alternator to a rectifier and mx-60 pv charge controller. It was at only 1450 watts too.
The readings bounce around on his instruments in the video so there is a lot of room for error in that hot number. I have wanted to use a pv charge controller for a while. The outback forums have a mention or two last I looked and it didn’t seem promising. But midnight solar specifically mentions and recommends settings using rectified output from a listeroid and alternator in their PDF for the midnight classic series of pv charger.
I think there’s merit in the study of the modern Inverter Generator, they are expensive, but the owners rave about the quality made ones, we simply need look at VFDs and these inverters.
They basically have an AC input, recitify it as efficiently as practical, and then pump up a DC bus that powers an inverter.
My question.. could this appliance be used as the heart of an off grid installation? We hang a battery off the DC bus, we use other power sources to charge the battery when possible, and we do it as close to the working voltage of the battery as reasonable to assure that the rectification stage costs us as little as possible.
We live in an age where we can find open source software for a cannon digital camera! Why not open source software for one of these 3 phase VFDs ? Could they become the heart of an off grid power plant, or the heart of an Electric vehicle if you were allowed to tune the software? Maybe it’s already out there?
We need be skeptical of any posts.. we need multiple tests, and it helps when we know the people and how methotical they may be in their approach to test things..
Midnight Solar has received praise form several people I know.. But.. I have not had time to follow him..
no time to proof read.. sorry..
What would it take to protect the output transistors on a vfd? I have a couple each from leeson and ge/fuji on various machine tools. They all mention that the user should not disconnect the outputs from loads under power. This would be common if used for a power system if I understand your posts. I guess they were talking about inductive spikes coming back to the transistors. When experimenting with DIY stepper motor drives I have used both diodes and capacitors for this,but that was dc. Maybe one of those ac surge suppressors like look like or are a capacitor with special properties? I don’t understand how they work.
Bill, maybe we tune your Question? How do they protect the transistors in the inverter generator? You and I know people will attempt to run both high XL and XC loads with IGs.. and the engineers will be forced to protect same. I do believe there’s a whole new series of MOSFETS or similiar that have far better built in protection, at least that’s what I thought I read.
As for the VFD, and using it for other uses, your example is perfect.. we need research first, not willy nilly try it 🙂 BTW, I smoked a 3 phase motor on my VFD powered generator test stand.. it wasn’t inverter rated, and I put it to use anyway…. whether it’s fish or an electric motor, it’s hard to un-smoke them..
What causes smoked motors with vfds? I am just past the edge of knowing what I am talking about. Is it a power factor problem where load speed leads to abnormally high currents? On my leeson speed master I can hit the enter button and get load on the display insead of rpm. If I am taking a decent cut on the lathe and I dial down the speed the load will actually go up. The only time I’ve ever had that vfd do a preventative shut down was when running very slow, like 300 rpm or slower for extended periods. Also does the carrier freq of the vfd cause winding problems with physical resonance? I have never damaged my 30-40 year old three-phase motors but I’ve read complaints.
Studying the inverter output does seem a good idea. Despite what people say on forums I mig weld and do anything else I want with out hesitation with the outback vfx and it causes no problems. I got it in 2005.
Bill,
Here’s my DIYer answer (uncertified, and no license to preach)
You likely get by with your older motors because they were built far better, (higher insulation class) Likely built during a time when value engineering was less important to a company’s survival.. We also need understand these older motors were likely designed to run on/off grid where voltages were less regulated, who wanted to take the chance at the time they were manufactured?
VFDs DO generate higher voltage peaks to generate the same effective power. It is the peak voltage that some of the cheaper 3 phase motors can’t handle because they are built to provide value, and the definition in this case means a motor that will do the job within the confines of the ANSI standards and the voltage peaks of a mechanically produced sine wave at the lowest cost. VFDs are NOT part of the design criteria.. period, and you better expect smoke, and expect the motor warrantee to be void if you show the VFD output to the motor.
Reality is.. people shop for the cheapest price, and the cheapest of the non inverter rated 3 phase motors generally make smoke first. It’s what I think, and others should take me to task if they think I got it wrong.
Is your drive a vector drive? I don’t know with certainty but I believe they keep power up at lower speeds. Mine just becomes feeble. On the leeson if I hit enter I can get rpm, freq, voltage, or %load. If I monitor voltage at low speed/freq it is can get very low. Like at 5 hz it’s probably 10 volts. I can check. I can stop the chuck by hand easily. There are a lot of parameters to set in the menu and some of them I’ve never played with. Possibly they are conservative default valurs. A vfd that flys out of the box vs one that crawls slowly unless tuned.
Slightly related, at least to the last few comments – I have been using a second outback vfx inverter/charger as a dedicated charger. I was dissapointeded that slow speed engine pulses do still make it on to my ac power. What appears to be happening, I have not scoped it, is that the power stroke is going through the charger and putting big dc bumps on the battery. Then the other inverter does not have so tight a loop that it can account for bumpy dc inputs. It’s not all that bad. But it’s actually a little worse than bare st-5 power in some ways. For example, with the st-5 I can see flicker in magnetic and even my one electronic tube ballast. But with cf bulbs I either could see no flicker or it was on the edge of perception. With the dedicated charger I can see pulses on the cf bulbs quite well. it’s not all that bad. It was just a temporary experiment anyway. The second vfx is to be used for its normal purpose. I am looking forward to trying a midnight classic as an engine powered charger. If it makes bumpy dc then it will have to be filtered.
Could you pull up the inputs to two of the igbt’s and run them all off the same signal so they are in phase? I know igbt’s, unlike regular transistors can be run in parallel. Have done it. Datasheet said so too. Also they had something like 10^12 ohm gate impedance so multiplexing the output from the driver logic ought to work.
I can’t imagine what would prevent you to get them at the same time..
I didn’t mean to say multiplex. I meant to say fan out.
Just remember gate drive is huge with IGBTs. You must have an appropriate gate driver to push to of them and then further, any timing or latency issues throws the full load at one of the IGBT’s. Thus running in parallel is not trivial.
For those who are not electrical gurus, basically, gate drive is like a relay or amplifier to push the high amount of energy into the gate (switch) of the IGBT in order to turn it on as fast as possible. If it raises slowly, then it acts more like a resistor turning on and thus massive heat is generated inside the IGBT. It’s hard enough to drive one IGBT let alone 2 in perfect fashion.
Sorry, meant to add more. You really are looking for a dual gate drive buffer chip to put between your existing logic section and the new paralleled IGBTs http://www.gndc-ups.com/web_users/webuser/1700V%20Dual%20IGBT%20Gate%20Driver.pdf
You also want to ensure plenty of low ESR capacitor and thick traces feeding that IGBT driver. While the quote above was for gate impedance, the thing to remember is the gate is basically a capacitor so you need that spec too. It takes time to charge (just like filling a cup) and the only way to charge faster is provide the lowest resistance (highest flow) and highest charge voltage (highest pressure), basically dumping the capacitor (bucket) on the power rail feeding the gate driver to charge the capacitance (fill the cup) of the gate itself. That energy for just a microsecond can be HUGE Amps. The gate drive was rated for 24 Amps just to basically charge a capacitor super fast. Wire traces, solder joints, and path length can create enough resistance to cause one IGBT to charge and thus turn on faster than the other one, thus taking the brunt of the load.
Anyway, point being is that I try to be as good of a mechanic as I am at electrical and electronic engineering. These gotchas I’ve learned from real world experience are worth sharing.
The key that I’m getting at is you need some serious math and calcs before even attempting to place 2 IGBTs in a sharing parallel setup, and then some serious testing to tweak it before power is ever applied. These things let the magic smoke out pretty quick. Further, I think IGBTs like to short when they blow, so in an inverter H-bridge, when both sides stay on (dead short), that’s one hell of a fireworks show.
After years good service they only quit when accidentally connected to the wrong supply terminal. They smoked and then stopped conducting.
The only problem I potentially had, but did not have, was that they were very, very static sensitive. I beleive the data sheet said they could be zapped by a static potential of only 2o volts. So they had to have conductive foam attached until the circuit was complete.
This thing was really crude by most anyone’s standards yet worked well. There were no traces involved. The mcu board was called pcbug. It was a credit card sized eval boar made by motorolla for the 6811e9. My power board was a RadioShack perfboard with the little copper rings around each hole. Point to point soldering with 22 gauge multistrand everywhere. The high currents were handled with multiple conductors. I think the 22 gauge was good for 6 amps and I ran about 3 conductors to and from each igbt. The thing was actually way over built since each igbt would take 40 amps and I had 10 of them, but the motor only took 72 amps. And each igbt would surge to 80 amps, I think. I did take the gate driving seriously and used the recommended driver and used the typical circuit in the data sheet.
I did use a gate driver on my lathe to drive 10 igbt’s in parallel. I think they were ir3740’s but that was 15 years ago and i could be wrong. They were 40 Amps each. The driver was, I think, made by intersil and had 6 pins. It took, I think, 24 volts and had dv/dt that was very high, like in the billions or even a trillion. This was the first and only project I’ve done like this it and worked well. I’m not very sophisticated electronically . Connecting transistors to mcu’s and displays and encoders is about it. What it was was a 6811e9 pwm controlling a forklift motor for a lathe. It had a bunch for diodes to handle the inductive voltage spikes Too. I worked well for years. I connected the power to the driver section to the battery at the 24 volt terminal with an alligator clip. One evening I accidentally connected it to the 12 volt terminal . All 10 of the igbt’s fried but I’d just bought a house and was ready to move my shop anyway so it was back to the stock 3 phase motor and a vfd.
My whole shop was in a storage center where for $115 a month I got a 10 * 25 room and 10 amps for 115 volts. So to run machine tools I used dc motors and a bank of batteries with a charger that could only draw 10 Amp before flipping the breaker.
fwiw and admittedly probably not much
my testing on the 195 based cogen was to get the highest charging efficiency i could get with an eye on the goal of an inverter/generator scheme
what i set as the standard to compete against was the st7.5 a commonly used generator of reasonable utility and cost.
what i first needed to determine was what exactly is the efficiency of the st7.5 as measured in BSFC (grams fuel consumed per kw/hr production) the best i could achieve turned out to be very close to 78% efficient, which i will accept as likely for a generator of its design and power class. From all the info i have from engineering texts, most of which i turned to were contemporary with the timeframe of the st design (~1940’s) it appears that single phase heads are at best 85% efficient only in heads over 50kva, with typical efficiencies in the upper 70’s to ~80% for those heads in and around the 7.5kva class… so my results seem to agree fairly well with published data.
while this is all interesting, the real value of the testing is relative
in that i have something to compare to that being BSFC with a common test stand and the same power source (s195changfa) so my thinking is now if i only change out one thing and retest i can come up with a relative comparison that is valid. swap out the st for another generator and retest with all else equal and you have a pretty good idea if you have something that will compete favorably.
so my next test was with the repurposed leece neville/prestolite 110-555jho alternator running at 24vdc nominal (yes the 555 is a 12volt unit and it is a 15 page explanation why this is the way to go), and i go into testing… the results were interesting
the 555 as applied worked out to be almost exactly as efficient as an st in BSFC (gr/kw/hr) however the st is AC and the 555 is DC.
so the problem then becomes the inverter losses which with the inverter i was using (a repurposed apc ups inverter group, 4 x 1400kva units) using two of them to get something about at the max output of the 555 alternator at 28.8vdc (charging voltage of a flooded bank) these ups units are about 86% efficient so when you factor in those losses we end up with 78% * 86%= ~67%.
this is obviously less efficient than an st head, however we need to be mindful of the following
1. the output of the ups system is pure sine wave, very low distortion, dead on 60hz power. that might be a fair tradeoff.
2. the ups inverter is not as efficient as other inverters are, some of which can reach to ~92% so,,, 78% *92%= ~72%
now that is within a stones throw of the st head and we still have the benefit from #1 above.
3. the engine can be throttle back from the requisite 1800rpm to 1200rpm with an decrease in fuel consumption that relates to an increase in overall efficiency of 5% points, the result now is a system that is ~77% efficient as compared to the 78% efficiency of the st head, and we still have the advantages of #1 above.
what i did not do and will be doing this fall is retesting the 555 at 48vdc nominal output (57.6vdc battery charging) to see what the efficiencies might be. i am about 90% certain at this point the unit will work out to be about ~2-3% more efficient than the st head as measured by BSFC (gr/kwe/hr)
that would be the ultimate goal in my opinion, for an offgrid charging and inverter/generator system.
when you consider the system for battery charging, this is where the system beats the st head feeding an inverter charger. the inverter chargers are ~92% efficient on average so you have an st head at 78% efficiency and in inverter charger that is 92% the overall efficiency would then be ~72%.
as opposed to what i know the 555 to be in a 24vdc nominal system of 78% and an expected efficiency of the 555 running at 48vdc nominal of ~81-82%.
that 6 to 10% gain in efficiency equates to many dollars in fuel either spent or saved. in an application where the generator is the soul charger source for an offgrid installation that 6-10% savings in diesel fuel at the end of the year is a amounts to a pile of money.
there are also other factors that can be addressed, such as improved efficiencies of the prime mover, the difference in an idi and a di 195 changfa is about 5% points in fuel consumption, the di being more efficient.
yes i like inverter generator designs
bob g
That is good efficiency from the alternator. I was looking at delco remy and some other alternators. The 24 volt efficient ones I can afford are 70% and $500. Like the 36si. The 55si is 80% but it’s $2500 with an msrp of $4400!
http://www.finditparts.com/t/214/manufacturer/delco-remy/products/1881569/delco-remy-8600453
Do you have a device to control the charging? Aside from just getting batteries their correct charging cycle there are useful tricks I do with a programmable charger. Like I’ll set the voltage from the engine input lower than from the pv input. That way the pv will keep at maximum and the engine will reduce fuel usage. The other way around the the engine will run full on and the pv chargers will decline perfectly good and free solar power, letting the engine burn more fuel.
i look forward to your changfa test results. I am looking for a second engine of some sort, for a time when there are nothing but thin aluminum engines available. If the changfa is efficient at low power like I use but also capable of high power charging it would be great.
What fuel consumptions per kwh did you find using the changfa and this alternator? I read your paper last night and this interests me. In calculating the alternator efficiency do you start with the engine manufacturers published data? I think my 6-1 says 268 grams/kwh. Are these reliable? With some of the images I’ve seen of crude manufacturing, which i repsect, i am curious if anyone there actually tests their engines for efficiciency or just copied orignal lister data. If the excellent, excellent drawings that were in my ashwamega manual were produced by the factory i would be shocked.
I have read efficiencies from listeroid generator combos of .125 gal/kwh at 2kw with an st-3, .129 gal/kwhr with an st-7 at approx 2 kw and .121 gal/kwh with a DIY axial flux and and mx-60 as a charge controller at 1.4 kw. All of these are so close that I don’t think much of the differences considering difficulties of measurement.
I am especially curious how the s195 performs at low power, low speed, like 1kw.
to start off i might as well answer your last question
first…
the first kwatt generated will always be the most expensive in fuel consumed, the changfa is no exception. it is only under max output that it is able to produce a kw/hr on .100 gallon, and that only at full temperature of ~205-215F which requires a closed and pressurized system.
i would have to go back and check how it does at low load conditions like a 1kw load, i would expect it to be around twice the best economy of full load.
*i just looked up a report my daughter did on this unit for a science project a back in ’09 from her notes it would appear the 195 driving the ST head will produce about 7100watts (as tested) using on average 36 gr/kw/hr… and at the lower end of testing 720 watts, it consumed 133 gr/kw/hr.
bear in mind that all testing was done with the 195 direct driving the st7.5, belt driving 2 of the 555 alternators, powering a bosch auxiliary 12v water pump and also the 12volt nissan sentra radiator electric fan (cycling on thermal switch)
while it is likely the 195 would do better without all the parasitic drags, extra alternators and pump/fan etc. it likely still would consume 3 times the fuel per kw/hr at a 1kw load as it would powering a 7kwatt load.
i think i have data that shows the consumption down to maybe twice the full load rating in BSFC if the engine is running at 1200rpm, however i would have to verify that.
there is a member on the forum that has mounted a heavy bolt on plate to increase the mass of the 195 flywheel, iirc it added about 130lbs to the oem unit… he was able to get the engine to run stable at ~650rpm. it sounded good and might make about 3kwatts max output, so it might do pretty well at a 1kwatt load,
having said all that, i am not sure the 195 is the best choice if all one wanted was a reliable 1kwatt max output, if BSFC was the main motive for doing so.. perhaps a smaller engine would be better suited at that low power level?
for instance the r175 changfa is about 5.5 hp at 2600rpm i think, so maybe with a heavy flywheel it could be brought down to around 1000rpm, the timing altered a bit slower and get a machine capable of a kwatt continuous output with better BSFC numbers at that level.
i haven’t done any testing on a r175, but i do have a couple of them and plan to do so at some point in the future.
so bottom line my take is this, the 195 is very good in the 4-7kwatt class of machines, being able to compete well with other manufactured gensets as compared by BSFC but it really does best at full rated output, where it is very competitive.
no genset in this class will do very well at a 1kwatt load, even the big boys have dreadful BSFC at that low load level in this class.
from reliable sources an 1115 will produce better BSFC of about .090 gr/kw/hr electrical, which is at full load of about 12kwatts or so with an st12 head..
i would expect a 175 to compete with a listeroid as compared by BSFC at full load and about 3kwatts output, however i would bet it would be a bit better at lower rpm, but i may well be very wrong on this one. we shall see.
now lets address published BSFC numbers
we can prove mathematically if their numbers are close, if we have an accurate load, accurate weight of fuel used, know the btu content of the fuel, and have an accurate compensated way of measuring electrical output.
if we assume their number to be correct, we can then mathematically project the fuel consumption of the genset in gram/kw/hr electrical.
for instance if the engine is advertized at using 300grams per kwatt hour mechanical, and we assume the genhead to be 80% efficient, and neglect drive losses because we are direct driving the genhead,, then it follows that we should see
a bsfc of 300/.80 = 375gr/kw/hr electrical at full rated load.
so then lets cross check from what we can determine as good numbers from other sources.
generator heads in this class are typically no better than 80% efficient, so it looks like the engine oem BSFC for the engine is valid.
for the engine to be more efficient the generator would have to be conversely less efficient (which is not likely to much of an extent) and conversely for the genhead to be more efficient the engine would have to be less efficient (again unlikely given other published data on genheads of this class) we know this because we can prove exactly how much fuel is consumed to produce an accurately/compensated for power factor kw/hr electrical.
bottom line from what i have determined the manufactures advertised BSFC is likely withing a percentage point of two of actual if the engine is average, broken in, operating at full rated load, at or near sea level, at or near an ambient temperature of 70 degree’s F.
i think if you are looking for only a kwatt output, maybe a smaller engine? heavy flywheel, all of which George has been alluding too, along with longer stroke, and maybe some other things, might come together to be the most efficient for this region of operation.
another thing to consider is the offset of battery efficiency, most flooded cells are about 85-90% efficient charging, so maybe the losses avoided here by a small diesel driven 1kwatt genset even though a bit less efficient than a larger set at higher output, still would be overall more efficient? that is definitely something to consider and would vary depending on installation, application and use/user.
bob g
1kw is a low figure for me. Sometimes I go that low. Usually it’s set to 1600 or even 2000. But I would like to be able to power much more, like 5 or 6kw if I get a larger mill. Maybe there is a range of engines in my future.
Bill i think you have arrived at the likely conclusion to a successful and most efficient system, that being the use of at least 2 different gensets, one small one large, and it might be that there are some folks that have a need for a third much larger set?
for me, it never made sense to drive a heavy intermittent load like a welder with a battery inverter system when portable gas drives are clearly superior at what they do, and on the used market are very affordable along with their ability to make AC power adds a bit of safety/redundancy that most would welcome. so i am thinking that i am pretty happy with the niche in my needs that the 195 fills, and am thinking the 175 or maybe even a minipetter i have might do duty in the 1-2kwatt range, and make domestic hot water in the process… the heavy loads like welders and other machine tools will probably be serviced by either a portable welder for welding needs, and maybe a 25-30hp engine driving a 3 phase stc head… for the heavy duty unit my obsession for efficiency will likely not be as much of a concern, mainly because the run times would be relatively short duration, maybe a half out ever few days on average. which is probably typical for an offgrid shop that does only what is needed for the immediate needs of the owner.
bob g
Bob this is in reply you your post about having a range of engines. There is no reply button so I am replying the one above where there is a button.
On the small side what do you think about small listers, like sr I’ve been watching YouTube vids of them this evening and they look overbuilt compared to many small engines. Some of the videos were of very old and well used engines still running. I was thinking one set up with your charging system would be a compact but heavy duty lower power system. The price on parts i was able to find seems high compared to listeroids but manageable, especially if they are durable as they seem.
Bill
let me check with George about posting a link to another site, i have
a 15 page white paper sitting there for those that are interested to download and it covers how this is done.
i don’t want to post a link until i know if it is ok with George to do so, also he might be ok with having a copy here, i dunno.
as for controllers, i have used and tested the following, Balmar, xantrex, hehr, amplepower, heart interface, and another who’s name escapes me just now. they can all be used to do what i have outlined in the paper, some with more programmable function than others, some more expensive too.
another controller that looks really good is those made by Sterling, i have recommended them for use and from what reports i get back they do just fine.
on the topic of automotive alternators, i would never recommend a delco for this purpose, nor would i recommend many others. the only alternator that shows promise and has been a proven performer is the 110-555jho. it was developed and marketed for use on mid and heavy trucks in the 12volt market… the white paper goes into detail as to why it is desirable to use this 12volt unit for 24 and 48volt operation, and why it is not desirable to use a 24volt off the shelf automotive alternator to do 24volt charging, at least as it relates to maximizing efficiency.
bob g
Whoa. The first hit showed 110-555jho at only $224 new. After your 24 volt mods what rpm does it take to make 2000 watts?
~4600rpm will get you 2880 watts dc (28.8volts at 100amps) with ~10volts at 3.5 amps excitation current (~35 watts) the unit will run thermally stable with a stator temperature of approx 175 degree’s F in a 70 degree ambient room temperature. the 555 is rated for iirc an underhood ambient temperature of over 205 degree’s F, actually it might be 220F i don’t remember. they are available from various truck dealers for around 170bucks on monthly sales, so check navistar/peterbilt/freightliner/ kenworth, etc… someone always has them on sale,, also many on ebay, that is for brand new units with no core charge. i have long been a strong proponent of this alternator and have many folks out there using them all over the world, that have decided to give one a try over the last 10 years or so. darn good units, well built, agreeable to modifications, and about as cheap as anything on the market today.
bob g
Bill
been thinking a bit more on the 1kwatt output scheme
understandably there is a need for 1kwatt supply more or less full time, more so than for a 3,5, 10 or more running 24/7… however consider this
because the generator has a very high cost per kw/hr in bsfc for that first kwatt of capacity and at full load the bsfc is but a small fraction of that first kwatt of capacity, it stands to reason that we ought to (from an efficiency standpoint) operate any genset at or near full rated power… the problem is there really isn’t much in the 1kwatt capacity genset that is very efficient. so here is a thought to kick around
if we use the battery bank effectively we can attain decent efficiencies, 85% is not out of the question and as high as 90% with agm’s and a tightly controlled charge regime.
so maybe we size the bank so that it can provide the sub 1kw/hr for maybe a half day (12hours) and recharge the bank twice a day at the higher and more efficient rating of the larger genset.
for instance lets consider a 48volt bank for illustrative purposes.
maybe we need 1kwatt of capacity, but likely that average is around 500watt continuous, 500 watts x 12 hours is 6kw/hrs
a 195 changfa and a good charging system can produce 7kw dc output, so even with the efficiency his on the batteries, of
6kw/.85%= 7.06 kw/hr to provide for recharge. that works out to a 1 hour run time twice a day.
now we can’t stuff 7kw/hrs into a battery bank in an hour and fully recharge the bank, but we can operated in the 50-80%soc range where the battery can accept high levels of current charging. we can do this for perhaps 6 days a week and then on the 7th do a complete recharge when we would then have to reduce the charging current to top off the batteries. this 7th day longer run time could also coincide with laundry day when we do things that take more time than an hour anyway and we have the unused generator capacity to put to use.
i think once the math is all done, the mid size genset such as what i have described is going to be very hard to compete with when it comes to trying to provide that low level of continuous power. i am betting that it will pencil out to be too costly to keep a small 1kwatt capacity generator running for long periods of time each day… at least for most applications
as we know the variable are many, what works or can be made to work for one, might well work excellent for another, or not at all for still another..
unless one has free fuel or some other charging source such as wind, solar, hydro or some overunity scheme (ok forget the latter) the costs of operation is going to be significant. anything that can be addressed in the design stage of such a project that affects overall efficiency of the system ought to be fully explored.
i know that there are those that are so inclined to keep their batteries operating in the top 10% of their capacity, so as to extend the lifespan of their investment, that end up spending twice or more on fuel (than is necessary) which equates to more wasted fuel in dollars than the batteries cost to replace.
never made much sense to spend 10k dollars extra in fuel to extend the lifespan of a 5k dollar battery bank, but there will be those that do this and never really put a pencil to it and never know.
fwiw
bob g
What is frustrating is that there is at least one technology for this that would please me and everyone else including the epa, possibly.
http://www.sunpower.com/library/pdf/productlit/Engine%20Brochure.pdf
Their 1000 watt unit at the bottom of the chart has a propane burner and built in linear alternator. It is 32% efficient. That seems to be after the alternator, not just the engine’s efficiency. That would be .116 gal propane/hour at 1 kw. If it were to use diesel as efficiently is would be .076 gal.hr at 1kw. This device does exist and is demonstrated. It is interesting to look at the efficiency graph and note piston amplitude. It’s peak efficiency is at 1 kw with a piston amplitude of only 9 mm. They mean stroke, I think. It works on gas bearings with no oil. Does that come from an external source- i don’t know.
i bet the cost of one of those units is going to be very dear indeed. probably enough to pay for a less efficient system and the extra fuel to run it with..
the only place i see one of these units excelling is someplace where miniaturization is paramount, and cost is of little concern.
don’t think they will be made in sufficient numbers to end up in the surplus market anytime soon either.
bob g
off topic, we don’t believe in over unity, but do we need be more cautious of claims in general? I offer the question.. not the answer!
No doubt, there’s a lot of glue sniffers who claim to vote that would spend the last dollar in the public treasury on magic. Evan Sayet best describes how these people think, and we know that the same minds that see a free lunch in finance see the free lunch in energy. BUT there are entities with a lot of money who WiLL fund nearly any feasible idea that might produce a more efficient power plant. I offer the Rail Roads and the Merchant Marine fleet as two of these entities, they live or die based on their efficiency and abilitiy to carry goods at lowest cost. And there’s a lot of research they fund that isn’t readily known by the public. If they could save one percent on fuel, it would be an enormous amount of money saved, and reason to invest in research..
We know that heat engines have been around a long time, even Jay Leno has a nice one that does real work. What we might recognize is that Sunpower claims to have made prototypes for 30 years, and still hasn’t been able to come up with an idea the free market might find interest in. After 30 years, there’s no order button for a simple unit that is even 10% efficient! We need ask.. is considering this fact part of critical thought? I guess that’s a personal question isn’t it?
Another thought about heat engines.. we know they were typically part of every wealthy estate around 1880 or so.. they worked, they pumped household water, why is it that we live in a time of laser cutters, CNC, and more, and not a single replica of these proven machines is on the market??
There is a huge unfortunate gap between what is possible, what exists and what you can buy. I hate that. Besides the video demos there are online nasa experimental evaluations of sunpower’s tech that verify their efficiency. Jeeze, I can’t believe I’m using a big government project like nasa as a reference. The least that can be said of nasa is that their overpriced taxpayer funded projects do sometimes work. The 1000 watt engine is about 6 years old, i think. Before that all I saw were 40-50 watt designs. I am not surprised a <100 watt very precise heat engine was not marketed over 30 years. The same could be said for a 1000 watt unit. I'd like one and some off grid types would like it but who else would get excited by it when they can buy a generator at home depot that produces 5kw for $300?
The order button, if taken literally is too restrictive a measure. There are some very interesting engines out that you can definitely have that do not order that easily. The capstone c30 is nearly 30 percent efficient, requires no lubricant, no coolant and has been available and sold all over the world to commercial users for a long time but I’ve never seen one offered that way.
This was interesting. a 750 watt stirling chp unit that used .3 liters of diesel/hour at nominal load. Here’s links to a used one on ebay uk, a manual for it and a spare parts supplier. I notice from the used ebay offer that they were almost 10,000 pounds sterling. It sounds like they were having problems with it. It also looks like it was far less efficient than the sunpower eg-1000. The grid tied home unit is still available. This is admittedly way too expensive to be something I would use.
http://www.ebay.co.uk/itm/Whispergen-Marine-PPS-16-Personal-Power-Station-/190557387353
http://www.ebay.co.uk/itm/Whispergen-Marine-PPS-16-Personal-Power-Station-/190557387353
http://www.onboardenergydirect.com/off-grid-power-store/whispergen-spares.html
How long does it take for your s195 to get up to temp? Is it much more efficient at running temp? I ask because I was thinking about short, high power runs vs long, low power runs.
I’ll take a crack at this.. the 195 will likely provide the best fuel/kwh figures with hopper cooling at sea level, or.. you can create a closed loop presurized system to simulate that condition. Most of us will settle for the 195F thermostat to allow for some heard room. safety over the need to get the last bit of performance. Running cold can cause excessive wear.
i removed the hopped, added a honda civic bypass T/stat housing and went with a 195F stat…
the radiator is an 87nissan sentra, with the thermostatically controlled electric fan.
the engine runs under partial loading (i give it a couple kwatt load to aid in warm up, and it takes about 3 minutes to get to about 160 degree’s which i figure to be close enough to lay the coals to it, under full load it is up to full temp open t/stat in another min or two.
i use a bosch auxiliary heater pump, 12volt dc and push the cooled water into the drain cock port on the bottom of the cylinder.
the engine will continue to climb in temperature to about 215 F when the electric fan comes on, it will then cycle ever 3 minutes or so between 205 and 215 or thereabouts… it doesn’t get hotter than 215 with max load and under 205 either… this keeps the T/stat fully open and it does not open/close like so many others have with large tank cooling and thermosiphon systems.
the engine burns very cleanly at that temperature, no signs of gray smoke until you get up over about 7.5kwatts output into a resistive heater bank, then it just starts to make some gray smoke, but very little..
in testing i usually don’t wait for a partial warmup before i start loading the engine, as stated i add a couple kwatts of load about 15-20 seconds after startup, waiting of course for the thing to stabilize in speed and get oil pumping where it needs to be… the engine doesn’t seem to mind at all.
without the hopper the cooling capacity of the block is quite small so warmup is reasonably fast… however
i did add a 1500watt block heater, it is a 1″ npt screw in affair, i screwed it into the coolant tank block off plate, and figure to add it to the automation sequence so that the engine can make a start, and do its thing with a couple minutes of preheat in colder months.
fwiw, the idi engine’s have that screw in starting wick plug, apparently so one can stuff a piece of treated paper into the prechamber to aid a cold start, i removed that and found a glowplug agreeable to rethreading to fit the hole. it also is in the automation sequence at startup, this alone makes for a very fast and cleaner startup of the engine.
because this engine is going to be integrated into a cogen scheme, the coolant system will be tied to an external water tank to store the heat, this heat in turn can be borrowed upon to preheat the engine prior to restart, simply by adding a line of code to the autostart system, wherein the bosch pump can be called upon to startup perhaps a few or more minutes before startup is effected, this would take some of the heat from storage and reintroduce it back into the engine, allowing for a faster startup and application of full load.
all sorts of ways to skin the cat.
bob g
just wanted to add this
i have no idea how much more efficient the engine is at full temperature over that when it is cold/er
the thing is to get accurate measurements the testing needs to be done in 15 minute increments in my opinion, and of course there is really no way to keep the thing cold/er for that length of time under load
not that i would suggest doing so or would want to do myself.
now the difference between running cooler, say 170-180F and between 205-215F is measurable, something on the order of perhaps as much as 1% point, but you really got to have very good attention to detail with your test equipment to witness that difference,, you sure are not going to do capture that use clamp on meters, hand held voltmeters, a calculator, and a set of resistive heaters as a load bank that shift all over the place every time a breeze blows through the shop… you have to use some sort of all in one watt/hr meter large enough to report in thousands of watts, that measures in real time and can accurately accumulate the power used by a shifting load… you just can’t do that and get down to the fine hairs of testing efficiencies any other way that i know of.
chasing small improvements in efficiencies is certainly a worthwhile endeavor, however it can be an exercise in futility without the proper test equipment. finding a half percent here, another 1 percent there, a quarter here and before long you are talking about real numbers.
fwiw
when i started out with this testing thing, i went looking for some published reports of what the oem gensets did in efficiency based on BSFC gr/kw/hr. iirc victron was the facility that did the testing, they tested
iirc about 6 or 7 moderately expensive packaged systems typical of what is used on boats/yachts that were in the 4-7kwatt class. i did my testing of my unit and was somewhat discouraged to find the 195 outside the group,doing worse than even the worst factory built unit,,, that is where my journey started. in the end i was able to put the 195 based unit within the scatter graph of plots of the commercially available units.
so lots of little things here and there all add up to getting efficiencies up there with the big boys. while all but one of the commercial unit will do better at lower loads, there was only one or two that could beat the 195 at full rated load, and that they did by very little.
going a bit further, the 195di engine’s are supposed to be a couple percent better in fuel efficiency than the idi versions, if this is truly the case, then my bet is a 195di engine based generator would beat out all the competition in that victron test. i have a couple of the di engine’s but have not tested to confirm this one way or another.
I asked before I understood how fast your system heats up. On my listeroid it takes far longer than that. Not too long after getting it I installed a 195 degree valve from napa as per instructions either on utterpower or on the utterpower cd. I also put a tiny hole the valve in case of a bubble. But it’s a heavy engine with a tiny output so I guess it will take some time. I like the idea of having the chp water available to preheat.
i figured why not give them the benefit of the doubt when it comes to claimed efficiency, it really doesn’t matter until as George states it there is a “buy it now” button on the website.
i skipped right to the likely price of such a unit, my bet is if it could be produced and if it was as efficient as claimed, and if it was reliable and if it was long lived, it likely would have a retail price of 30grand a copy. at least priced to the government in limited production which we all know they would be deployed in for a decade before they started to make their way into the general retail market. btw. notice there is a butt load of “if”s associated with this analysis.
even at 10 grand, which is very likely, one can buy a really nice system and pay the fuel efficiency penalty for the life of the sunpower system in question.
i don’t see this as anywhere near reality for offgrid use, at least not in a cost effective offgrid installation, ed begley notwithstanding.
i think we can get to within 95% of their claimed result for a small fraction of the cost of the sunpower unit. remembering of course that claims is all they have at this point, we can’t verify those until such time they are actually in use in offgrid applications, can we?
This is a very good read about nasa validating a 1000 watt sunpower engine in 1983. They had many initial problems and performed a number of optimizations but it was finally discovered that a leaking valve in their test instrumention was responsible. Their conclusions were 1200 watts, 32 percent efficiency, nearly silent and no obstacles to mass production.
This seems worthy of DIY study and application.
http://www.ornl.org/sci/ees/etsd/btric/eere_research_reports/thermally_activated_technologies/engine_driven/stirling_rankine/modeling_and_simulation/doe_nasa_1005_1/doe_nasa_1005_1.pdf
looks like the engine is reported at over 32%, which to me means less than 33%, likely more closer to 32 than 33 or they would have reported it to be “nearly 33%”.
where i am going with this is to box in a number, and then qualify it as being mechanical efficiency, or thermal efficiency, not overall fuel input vs kwatt electrical output.
i would expect one to have a real serious challenge to find a suitable generator/alternator in the kwatt class that is going to be over 85% efficient without spending huge money.
so 32.4% heat engine efficiency reported * 85% = 27.54% overall efficiency (fuel burned vs electrical output ) that with a very expensive high efficient alternator, and more like 25.92% with a more reasonable priced 80% alternator.
i am fairly confident i can prove the changfa to be very close to 32% efficient mechanically/thermally
that is in burning fuel to make mechanical power at the crankshaft. direct driving an st head of ~80% equates to about 25.6% overall efficiency
clearly the extra efficiency of the sunpower unit which is less than a percentage point overall, and only if it is coupled to a better generator, comes at a significant premium.
going a step further, we know of at least one qualified user of the changfa 1115 driving an st12 that is able to produce numbers in the 33-34% range for the engine and 82% for the generator (maybe a bit more on the genhead, i don’t recall)
so 33 * 82%= 27.06% overall to as high as 27.88%.
this leaves me with the impression that the sunpower units will never take hold in the offgrid market with any real market penetration until such time that they come way way way down in price and until such time that they can be coupled to a suitable generator that is at least 85% efficient and also reasonable in cost.
interesting as they are, not sure how practical they will end up being for the average installation. now for use in space exploration, clearly they have an edge, not even the chinese is going to put a changfa in orbit to power the project 😉
probably not a very appealing analysis on my part, but i don’t think it is far from reality?
with that said, i would be the first one to buy such a sunpower unit if it were to come up on the surplus market for the typical pennies on the dollar. why not?
bob g
In the first link I had, which was 25 years after this NASA report and on a different engine, they give a graph with electrical power, efficiency and piston stroke. It’s on the bottom of page 3. Tested at 1000 watts and 9 mm stoke they show %32 efficiency. Given the NASA paper that I linked I have no reason to doubt their test. While I like that a lot it’s not my overriding interest. If it is 30, 25 or 21 percent this looks to be something that could make power anytime day or night at the 1kw scale with very competitive efficiency and not get the user in trouble with the EPA or neighbors. I agree it is not something I will be able to buy anytime soon. If they have not provided these to end users for 30 years why would they start now? It looks very, very interesting for DIY, though. From the NASA paper, the power piston seal looks to be the most intimidating tolerance. It is just tight clearance. No piston rings and no contact. It is about .025 mm. But it is on the cold end so possibly expansion would not be a problem. They use gas bearings, but why not linear bearings on ground hardened shafts from mcmaster for a DIY project? Also the free piston idea sounds neat but it looks like there is a lot of theory and experience required to make it work. What about sealing a fly wheel and comnecting rod inside the pressure vessel with a magnetic clutch driving an alternator outside? They were running the free piston engine at 60 hz, so a 3600 rpm flywheel.
Considering the engine that started this thread was EPA tier 4 as is the laidong km385 3 cylinder, can you think of anything technical that would prevent chineese manufacturers from offering a cleaned up s195 that is EPA certified? Do know of my limits on heavy iron engines that make them dirty?
I admit to being soft on this stuff. I look up eestor about 2 times per year and am always surprised and disappointed.
We named this engine EV80, it’s water cooled, V-twin cylinder diesel engine. Rated power about 19HP/3600rpm, with electric governor and aluminum engine body, the net weight is only 57.5kg(without radiator). However, it’s a PTO shaft output engine, without SAE flywheels and housing.
Glad to get a visit from one who named it. It does seem there are a number of these designed to power things like the larger riding mowers, and even small skid stir units, so maybe not all are PTO units?
Good write-up. I definitely love this website. Stick with it!