thinking of exploring another option

[rl71459]

chris

I think the belt would be less efficient than a transmission. I do think you could use a fork truck engine. although I dont think that is an advantage unless you can find the right one... if it exists.

I also think that when some of the more knowledgable members read my lofty post, they will likely advise of the cold reality of such an approach... Maybe I'm wrong but it all sounds to good to be true for the average DIYer.

Rob

[mobile_bob]

a very good manual transmission probably will still eat 10% of the available power, an automatic would be out of the question
at the low power levels we are seeking due to the hp needed to drive the internal pump, heating and converter losses.

a well engineered belt drive is on the order of 2% in losses.

another issue with using a transmission and shifting gears will be a problem in maintaining stable rpm
i suppose one could put the belt driven governor on the genhead instead of the engine, but not sure in the end
if the gain in utility would not be largely or wholey offset by the losses.

bob g

[Lloyd]

FORD VALENCIA (VSG) engines are currently available in only one model, a 1.3L engine rated at 32.8hp at 2800 rpm. (A limited supply of service replacements for the earlier 1.1L size with a continuous rating of 27.5hp continuous at 2800rpm are still available).  These four cylinder engines are very smooth and exceptionally quiet when compared to most air cooled engines. Either model can be CARB (California Air Resources Board) certified when in equipment requiring less than 25 horsepower and can operate on gasoline, LPG or natural gas.
http://www.powertechengines.com/20_30.html
Additional information is given on the Ford Power Products web site at  Ford North American Engine Chart, which also has a link to a .pdf file version of the VSG-413 engine data sheet.

VSG compact engines include cast iron cylinder block and head for durability, replaceable exhaust valve seat inserts for operation on dry fuel, and five main bearing crankshaft for smooth performance. We are aware of VSG engines reporting in excess of 14,000 operating hours before repair in co-generation applications.

Valencia engines are distributorless (DIS)! No more replacing ignition points, condensers, distributor caps or rotor . . . there isn't any! Scheduled ignition system maintenance includes only spark plugs and spark plug wires.

Compact, these engines weigh less than 240 pounds, are 29"H, 25"L and less than 20" wide with radiator. Aerial lifts, sweepers, generators, carpet cleaners, and airline ground support are just a few current applications for these engines.

[BioHazard]

Interesting web site. Here's a story about 50 year old Ford pump still running on gas:
http://www.powertechengines.com/Ford254WaterPump.html

Really doesn't surprise me that much with a big old hunk of American iron...then again I drive a 37 year old truck every day. (all original)

I'm really thinking hard about a CNG conversion for the truck now...we're talking a dollar a "gallon" for natural gas or $3.29 for premium unleaded with 10% ethanol and even more for diesel. I see some home CNG compressor units on ebay...tanks are sure spendy though.

[Lloyd]

How about a spark ignition Kubota, it's the same engine as the super-mini diesel factory converted to gas/lpg.

Lloyd

http://www.ai-engines.com/pdf/kubota_engines/spark/wg_df752.pdf

[rl71459]

Dammit Loyd!

Now I want one of those little Kubota's. My wife is gonna kick my ass if I drag one home!

Rob

[BioHazard]

How about a spark ignition Kubota, it's the same engine as the super-mini diesel factory converted to gas/lpg.

Lloyd

http://www.ai-engines.com/pdf/kubota_engines/spark/wg_df752.pdf

I like...how come the cool stuff never has a price tag? 

I still would like to know more about the total combined efficiency of natural gas and diesel. If you convert a diesel engine to spark ignition like that kubota, will it run better on diesel/NG mix or straight natural gas with a spark?

[jimmason]

FORD VALENCIA (VSG) engines are currently available in only one model, a 1.3L engine rated at 32.8hp at 2800 rpm. (A limited supply of service replacements for the earlier 1.1L size with a continuous rating of 27.5hp continuous at 2800rpm are still available).  These four cylinder engines are very smooth and exceptionally quiet when compared to most air cooled engines. Either model can be CARB (California Air Resources Board) certified when in equipment requiring less than 25 horsepower and can operate on gasoline, LPG or natural gas.
http://www.powertechengines.com/20_30.html\

wonderful thread here guys.  a very interesting read.  and where did tim come from?  he seems to know everything about engines.  thank you for all the knowleged explored here. 

here below is what i've learning investigating the same.  i too think the fuel hacker future is increasingly in spark vs diesel. 


-----------------------------------------

inline 4s and 3s

sadly, the ford vsg engine is gone.  i wanted to use it for our rig but couldn't make it a regular sourcer.  its still a great engine for a one off, and already set to go with gaseous fuels usually.

the nissan A14 and A15 are similar go to solutions, but they too are no longer available new in the US new.  i tried that too.  lots there used, and they are well proven and loved.  for one offs, a great choice.

the kubota 3cyl 962cc is my current favorite.  they are 3k new, but nearly no used.  the oil field guys report 15k hours and still going on the first prototypes that were put in somewhere in montana.  kubota is making noises about coming out with a bigger one.  so far unseen.

the current gm small industrial spark engines are here:
http://www.gm.com/vehicles/innovation/powertrain-technology/engines/specialized/industrial/industrial_engines.jsp

people seem to frown on the 1.6 and 2.4 4cyl vortecs as having too much plastic and not terribly robust.  (no personal experience.  anyone here have one).
the 3.0l 4cyl is another story.  it is a full cast iron motor with a long history.  i think (maybe) a descendent of the iron duke, but not sure.  the 3.0l gets lots of marine use too.  the gm suppliers in the oil fields steered me away from anything below this.  the v-6 and v-8 vortecs in the industrial lines are highly regarded from reports so are

the current line of ford engines seem the choice in the 4cyl sizes.  i tend to see current gen builders using the fords in 4cyl, then chevy in v-6 and v-8.  can anyone assess this summary?  my confidence in it is middling.

ford has a 1.6 and a 2.3 inline 4 currently.  i do not know the gen or pedigree of these engines.
http://www.edi-dist.com/ford_TSG_416.asp
http://www.edi-dist.com/ford_DSG_423.asp

is this the ford engine you all were reviewing positively a few pages back?  not sure if that was a previous generation or not.

the toyota r22 seems a wonderful choice with lots of parts.  it seems one wants to stay with the double timing chain versions to minimize their known propensity to break and take out the rest of the show. 

the wisconsin v-4 engines seem about gone.  not much work on them these days to keep up with emissions issues.  a side valve engine gets difficult.
http://www.mgbryan.com/products/engines/wisconsin

diahatsu has a 950cc 3 cyl that gets used in small ute trucks all over the world, but not too much in the us.
http://www.daihatsu.com/catalogue/engine/showroom/

-------------------------------------------------------------

v-twin options.

in the v-twin world, there are growing water cooled options.  i went through the large air cooled options and found them a bit loud, and the lack of water to do things is less than ideal.  i decided that water was not negotiable.  otherwise, kohler goes up to 980cc and it is a great engine. 

kohler has a 750cc water cooled job for about $1900
http://www.kohlerengines.com/onlinecatalog/productDetail.htm?productNumber=Aegis%20LH755

kawasaki also has 750cc and 850cc water cooled units.

750cc water cooled
http://www.kawpowr.com/engines/detail.aspx?id=6&cat_id=1

850cc water cooled, efi
http://www.kawpowr.com/engines/detail.aspx?id=54&cat_id=1

at least on the kohlers, the mech governors don't like to perform well below about 2200rpm.  they get particularly fussy below 1800rpm.  the weights are calibrated for elsewhere. 

subaru-robin doesn't have any water cooled

yanmar is diesel only

perkins no spark at small scale


but course there is the harley.  many generations and many parts there to make your slow speed shake the house down thumper . . .

j

[TimSR2]

On the subject of adding a distributor to an engine that didn't have one before, such as converting an existing diesel to spark ignition. This I have seen done.

A very handy old friend of mine had a machine shop powered by a 8 hp Fairbanks Morse gasoline engine, but the original ignition system failed and was hard to find parts for, and was noisy even when it worked.  Rather than change the engine out to something more modern, he added a 70's datsun distributor to it, on an external toothed belt drive. IIRC the gears and belt were from a vacuum cleaner power head.  He just fitted  a little gear, added a zerk fitting to it for lubrication, ground off the points cam,  used one wire on it. Engine ran fine for years that way in daily use.

It looked pretty wild, but it worked great.  At the speeds these engines turn even a bicycle chain would work.

The point I wish to make here  is that it is probably easier to knock down the compression ratio by adding gaskets or base shims to spark convert a diesel than some of the other things we have discussed in here. For many of us that would mean being able to keep their investments  and just change direction a bit.  So putting a lister CS or a changfa on NG or propane is a reasonably straightforward proposition. And they have the mechanical governors we need for electrical production built right in.

One need know the CC displacement of the combustion chamber, (easy to measure for yourself)  thickness of gaskets  and the bore and stroke, and what compression ratio you want achieve. It doesn't take much shimming to knock a few points off the CR. Calculators are online on most racers websites. 10 to 1 is  a good conservative number for propane,  or 12 to 1 for NG.

Then just get rid of or disconnect the pump(s), Connect the governor to the carburetor throttle lever somehow, stick a sparkplug in the injector hole somehow, pick one that doesn't hit the piston crown.  Bodge on a modified old 4 cylinder distributor with a toothed belt or a chain drive, install your lockoff and mixer....  Adjust spark timing to about 25 degrees total advance..... crank her up and set your fuel mixture as lean as possible.

Then some fine tuning for governor response, and ideal spark timing and fuel mix and you have a lovely low speed  understressed super quiet dry gas engine.  At reduced power of course :-(

[jimmason]

 So putting a lister CS or a changfa on NG or propane is a reasonably straightforward proposition. And they have the mechanical governors we need for electrical production built right in.

Then just get rid of or disconnect the pump(s), Connect the governor to the carburetor throttle lever somehow, stick a sparkplug in the injector hole somehow, pick one that doesn't hit the piston crown.  

interesting coincidence in the universe that otherwise tends to not cooperate:

1. the injector hole size in a standard lister cs head is a perfect fit for a standard automotive long reach spark plug.  you can even repurpose the injector bolt down assembly with a hollow tube to hold down the spark plug.  for those who didn't see the earlier threads, here's our doc on doing so.  http://www.gekgasifier.com/forums/showthread.php?t=312.   (we later did it through the compression adjust plug, so as to retain both the diesel and spark ability at the same time.  you can see that here: http://wiki.gekgasifier.com/w/page/30448258/Spark-conversion-for-Lister-slow-speed-diesel-engines)

2. the injector hole in our local changfa r175 is about perfect to insert a 10mm motorcycle/chainsaw plug.  there are now 10mm and i think 8mm very small spark plugs that make installations in these smaller holes possible.  some engines you can likely even get them in the glow plug holes.  

so in both the lister and changfa case, you can convert to spark without machining or compromising the original motor.  and as tim said, adding gaskets is easier than milling heads and considering new piston clearance issues, on the road to reasonable compression.  

there are many ways to spark the result.  one electronic option using an arduino is explained here: http://wiki.gekgasifier.com/w/page/30448258/Spark-conversion-for-Lister-slow-speed-diesel-engines.  this is ken boak's work.


jim

[mobile_bob]

while i find the spark conversion of a diesel interesting, the engine will have to have its compression reduced
this is not the case for a dual fuel diesel, where there are examples of the chinese engine's with greater than 17:1 compression
doing just fine on natural gas, and there is evidence that propane can also be used but with a lower percentage of offset

a couple of advantages

1. the engine does not need to be modified

2. no spark plug and ignition system

3. no alteration to the governor or fuel system, allowing for seamless changeover to diesel and back again

4. lower emissions, lower NOx, lower particulate, lower co2

5. perhaps most importantly little to no loss in efficiency or output power

disadvantages include

1. having to have two fuel sources in order to run in dual fuel mode

2. possible detonation, rough running, vibration, damage if the gaseous fuel is not meter correctly to suit the load on the engine.

quite frankly i don't know why the gasifier boys haven't worked more with the small diesel in dual fuel mode, aside from the need for a pilot fuel
(diesel) the pros more than offset the cons in my opinion.

having said all that, i too plan on doing some experimentation at reduced comp ratio and spark ignition, however it would appear that the diesel left as is
and fueled in dual fuel mode would outperform and be far simpler to deploy.

at least that is the way i see it... maybe i need to clean my glasses? 

bob g

[TimSR2]

2. possible detonation, rough running, vibration, damage if the gaseous fuel is not meter correctly to suit the load on the engine.


Doesn't happen. Methane and Propane have  a much wider useable range of efficient air/fuel mixtures than gasoline, and so much higher octane rating that pinging is rarely a concern...   if the mix is too lean the power is low, if too rich the exhaust smells fuelly. They are easy to tune by sound and smell.

If the CR,  load, and ignition advance are kept within reasonable limits, a drygas engine can be run at WOT virtually forever. The valve seats will probably clap out a couple times in the life of the engine, if not made of Stellite. No big deal, Stellite seats aren't very expensive at  a good automotive machine shop.

[mobile_bob]

Tim

it most certainly is a concern in a diesel engine that fueled with natgas or propane in dual fuel mode
if you exceed the upper offset limit (which changes with loading and engine design, along with compression ratio) you end up
with vibration, detonation, pressure spikes and engine damage.

this is a totally different animal than a gaseous fueled spark ignition engine where the comp ratios are from 10 to 12:1

a diesel engine running in dual fuel mode often is higher than 15:1 and sometimes as high as 20:1

read the test results from the pdf link i provided for the bangladesh testing

at full load the amount of natural gas has to be reduced from about 88% (at 75% load) down to 67% at full load
otherwise the engine becomes very erratic in operation, with heavy vibration/detonation and other less than desirable things happening, that
left unchecked usually end up causing engine damage.

natural gas, and definitely propane does not have anywhere near high enough octane rating to operate  at very high compression ratios in a spark ignition
engine, and in order to operate successfully in a diesel in dual fuel mode certain metering must be adhered to on the the rich side,

on the lean side you can get away with whatever you like, the only thing you lose is fuel cost savings by running overly lean rather than up to near as practical to the offset matching the load.

excellent matching of the amount of nat gas to the load will require some sort of computer control to optimize to the Nth degree, however this is a very narrow window to operate in, the window widens if we back off the amount of natgas and run at less than optimum offset levels.

i think that is a fair trade off or compromise, at least in testing
after deployment it might be that a computer control to adjust the offset on the fly, might well pay for itself in fuel savings very quickly.

bob g

[jimmason]

quite frankly i don't know why the gasifier boys haven't worked more with the small diesel in dual fuel mode, aside from the need for a pilot fuel
(diesel) the pros more than offset the cons in my opinion.

here's at least what happened with me.  

in principle, i agree is sounds great.  in practice, i found the dual fuel control on these small engines to be extremely touchy.  it takes such a small amount of liquid to get to no load full rpm, that a minor error in your set liquid amount can lead to an overspeed.   larger engines with larger rpm seem to have more running resistance you need to overcome to get to speed, thus less sensitivity in the liquid set amount.

also, it only really works for the lister, as you can get to the governor linkage and detach it from the injection pump so you can use the gov for your gaseous valve, and pin the injector pump where you want it to hold steady.  on the changfa, it is all internal and you can't easily repurpose the mech gov to control your gaseous fuel, nor easily hold the injection pump in a single place.   doing it the other way (pinning the gaseous portion and varying the diesel) gets into even more problems.

before actual experience, i too thought dual fuel would be the way to go.  that's why i started with the lister and china diesels to make integrated gasifier gensets.  you can see the early lister and china diesel ones here:  http://www.gekgasifier.com/wpgallery/gek-gasifier-genset-older-versions/  it didn't really work that well.  the result was not something a non-expert should ever touch.  also, i just got tired of fighting the variable quality, old engineering and weight issues of the lister-changfa options.  i wasn't finding a total value.  it was not "cheap" in the end.  so then i started on the v-twin route spark, which you can also see above.  then the kubota.  

if one has a good and constant load, all should be fine.  but as soon as you have detached the injection pump and pinned it in some place, you no longer have the certain safety in overspeed that the governor usually provides.   if doing dual fuel with the liquid set for pilot, i would encourage only doing this with a solenoid shutoff that is run in parallel with spark.  don't pin the liquid rack physically to the run point.  put it on a solenoid to the run point, thus when you shut off the ignition, the rack still goes to absolutely shut.  the pilot dual fuel can be sneaky and easily get out of control.  

remember, diesels can run away on crank case bypass oil.  this is why some have intake dampners.  true, not usually needed.  in a dual fuel pilot injection scenario, if a hack injection rack set screw can easily come loose and bad things will follow quickly.

then adding the new butterfly to the above, i was quickly getting into as many or more control issues in dual fuel than with a spark engine.


more reasons.

wood gas tar converions falls apart at low pull rates, as temps fall.  minimizing wood gas use has not been the problem.  at this point i can run down to about 1kwe without external gas dumps and still keep things hot enough, but that was far from the case in the beginning.  dual fueling only made the low end fuel consumption lower, which was the wrong direction to be going.

also, after one has suffered through the pain of getting a wood gas system to work, it is a let down to use any liquid fuel at all.  it is much more pleasurable to run 100% wood gas.  that is the magic.  junk in - -  power out.  it is better undiluted.

all this led to an assessment that there was no "simplicity" and little pleasure to be found in the dual fuel small engine scenario at least for wood gas.

this calculus may change if working with nat gas.  and mileage always varies given your specific context.  i just clearly wasn't working out in mine.

jim

[BioHazard]

On the subject of adding a distributor to an engine that didn't have one before, such as converting an existing diesel to spark ignition. This I have seen done.

I think you would be much better off with a distributorless system. I've always hated distributors. There are a handfull of aftermarket spark systems mostly based on Ford EDIS parts. The Arrow 4 and 6 cylinder engines have a distributorless CDI setup. Probably some efficiency to be gained if you're not driving a distributor...

while i find the spark conversion of a diesel interesting, the engine will have to have its compression reduced
this is not the case for a dual fuel diesel, where there are examples of the chinese engine's with greater than 17:1 compression
doing just fine on natural gas

And with that I have to wonder...is that a good thing? Is it a simple "rule" that more compression = better efficiency? Or is there a certain point of diminishing returns? Something I have noticed about all these dedicated natural gas type engines we've been looking at, like the Arrow units, is that they are not converted diesels, and they usually only have 9 or 10:1 compression, even though the rest of the engine is optimized for fuel efficiency and natural gas. Why do the commercial spark ignition NG engines not use a much higher CR? Obviously it's not about saving money, when the engine cost probably 15 grand or more...

With my system I would really, really, really love to be able to produce electricity at the same rate as the power company - though according to my calculations I'm still going to be at 16-17 cents/KWH vs ten cents from the PoCo. I need a more efficient engine or cheaper gas. They won't notice if I dig a hole next to my gas meter will they?