engine designation, LP conversion - Enquiring minds

[bitsnpieces1]

  Just a couple of questions for general comment.
1)  Would it be fair to use the following designations for engines?
   Listeroid = Vertical cylinder, TWO flywheels, watercooled.
   Petteroid = Vertical cylinder, ONE flywheel, water or air cooled.
   Changfa type = Horizontal cylinder, one flywheel, water cooled.
Even though we know that all of the combos were used at some time. 

2)  Thinking about converting a Listeroid to LP gas as fuel. 
   Install LP gas carburetor,  pull injector and install spark plug,  remove unneccessary items (injector pump, etc.).  Could also keep injector and use as ignition source for LP.  Intent is to use Listeroid as  fixed generator system running from large LP gas tank for backup power.  Would eliminate storage of Diesel/BioDiesel/V.O. and carbon buildup, etc.  Make any modifications to create a dependable, slow speed, efficient engine.   Also, might meet EPA requirements. 

Any coments or suggestions welcomed. 

[fattywagonman]

Hi Bits,
I'm in the process of doing something similar to the petteroid... Replace the injector with a spark plug, install an electronic ignition... I think it should work pretty well in the DI engines..

[GuyFawkes]

2)  Thinking about converting a Listeroid to LP gas as fuel. 
   Install LP gas carburetor,  pull injector and install spark plug,  remove unneccessary items (injector pump, etc.).  Could also keep injector and use as ignition source for LP.  Intent is to use Listeroid as  fixed generator system running from large LP gas tank for backup power.  Would eliminate storage of Diesel/BioDiesel/V.O. and carbon buildup, etc.  Make any modifications to create a dependable, slow speed, efficient engine.   Also, might meet EPA requirements. 

Any coments or suggestions welcomed. 

there is a formula somewhere, do not have it to hand, for the voltage and energy needed to run at spark plug at various compression ratios.

If you are running standard 16+ to 1, no ordinary ignition system, whether 12 or 24 VDC, will even look at it.

NB "ordinary" does not mean points and coil, it means "not bespoke"

it takes *serious* energy to run a spark at 16+ atmospheres, and that means all external stuff like HT leads etc has to be similarly *serious* special kit.

without running the numbers and basically just guessing I'd be surprised if anything less than 100 KV would do the job, you're probably looking at a high energy magneto rather than anything electronic.

[bitsnpieces1]

  Since I'm looking at making it work !whatever!, magneto is doable, might use diesel injection as ignition source as mentioned in other posts, say 10% power from diesel - 90% from LP.  Also thinking of:
1)  drilling crankshaft for oil passages
2)  replacing piston oil pump with gear type (constant flow)
3)  dynamic balance each flywheel seperately then on up to entire rotating assembly
4)  increase sump capacity [openup back of crankcase and add volume there]
5)  and whatever.
  Inclination is to use modern technology to update engine while keeping it a slow speed, heavy casting engine.  Sortof what you would do over the years to improve dependibility of design without changing the design itself.
  Since this is a think and plan situation at the present and if it comes to be, will be a test bed to a certain extent.  Electronics not out of the question, such as 'discrete component' CapacitiveDischargeIgnition rather than solid state sealed ignition (non-repairable).  Perhaps mechanical relays instead of electronic switching.  Power consumption for addons will need to be figured in, cost vs benefit.  Benefit = ease of fixing, long lasting, enviro. friendly, etc.
  This is a good place for the monitoring equipment covered in another post.  What do you think of the idea of bubbling the exhaust through water to extract things like NOx, to test levels? 

[cujet]

Not so sure on that IGN situation you describe, Guy. I have some limited experience (4 years) with a Westinghouse Knock engine. It had a variable compression ratio and could achieve about 13 to 1 in original form. We did some minor mods to achieve 20 to 1 to test various fuels. The original IGN system was capable of lighting it off at all times. And that was a points and condensor system. By the way, this engine was shut off by an ignition switch! It is true that it takes more voltage to jump a gap as the pressure increases. However it is OK to make that gap smaller!

I also have plenty of high compression race car engne expereince. The typical NA maximum is about 14.5 to 1 on race gas. However there are plenty of turbocharged race engines operated at very high boost levels. Manifold pressures as high as 75 PSI are possible. I currently run a 9.5 to 1 turbo engine on 23PSI boost with near 100% VE. That equates to well more than a 20 to 1 effective compression ratio. And I am using OEM Mazda coil packs with an aftermarket ECU driving them.

Chris

[dkwflight]

Hi This is not a critisisim(sic).
Do a little more research.
There are plenty of Natural gas engines that use diesel njection for ignition, CAT is one.
One version uses NG at a steady flow and the diesel does the variation. the normal rack movement is just moved towards the idle end.
You can use a gaseous  carb for the load variation with the governor moving the butterfly to take up a load.
Check the Waukeshaw 
http://www.waukeshaengine.com/ http://www.arrowengine.com/media/literature.htm
& Arrow engine site
. There gas engines are down around 4 or 5 to 1 compression. You could make a spacer of aluminum plate and two head gaskets to reduce compression, maybe a 1/2" plate?
Somebody posted that they had free natural gas. Do you?
Good luck
Dennis

[Doug]

In the Nordstrom tests done for the Swedish govmerment in the 1950's and 1960's several trucks and tractors were converted to producer gas using pilot injection ignition. It worked very well from what I read in the technical papers but there were some problems with some engines needing compression ratios dropped to 14:1 and timing advances in the 5-10 ranges. CNG has a high octane rating but my suffer from many of the same problems. Nordstrom reported precup engines didn't run well in dual fuel mode and was only able to manage a 25-30% fuel substitution. Engine wear was less in many cases than on diesel and although emmissions were not the goal of the study it was observed that soot decreased.

Doug

[GuyFawkes]

Not so sure on that IGN situation you describe, Guy. I have some limited experience (4 years) with a Westinghouse Knock engine. It had a variable compression ratio and could achieve about 13 to 1 in original form. We did some minor mods to achieve 20 to 1 to test various fuels. The original IGN system was capable of lighting it off at all times. And that was a points and condensor system. By the way, this engine was shut off by an ignition switch! It is true that it takes more voltage to jump a gap as the pressure increases. However it is OK to make that gap smaller!

I also have plenty of high compression race car engne expereince. The typical NA maximum is about 14.5 to 1 on race gas. However there are plenty of turbocharged race engines operated at very high boost levels. Manifold pressures as high as 75 PSI are possible. I currently run a 9.5 to 1 turbo engine on 23PSI boost with near 100% VE. That equates to well more than a 20 to 1 effective compression ratio. And I am using OEM Mazda coil packs with an aftermarket ECU driving them.

Chris

I could be wrong, the one time I tried it was one one test bed engine, must be 25 years ago, I was measuring the voltage with an EHT meter and power by three turns of magnet wire around the HT lead, above 13:1 started to get serious problems and only cured them by whacking the voltage waay up there.

I actually looked for the "voltage required to jump an air gap of x at y pressure" formula last night and buggered if I know.

all this talk of high voltage reminds me that I have three surplus MOD radar EHT PSU's on the shelf behind be and it's about time I made another jacobs ladder to give this place the authentic insane scientists workshop in black and white movies feel... lol

[bitsnpieces1]

  From what I know, the standard car type ignition [points type] develops about 20-25 Kv spark.  That was the reason for the popularity of the early CDI ignitions at about 50-60 Kv.  The one I had would give about a 2inch hot blue spark in air.  More modern electronic ignitions and CDI ignitions do about the 50-60 Kv.  I do seem to remember something somewhere that high compression did need a higher voltage spark, something about the psi tending to prevent ionization necessary for a spark to happen.  Looks like a great topic to research more.  I think it was in some papers about the early CDI setups or possibly in present day websites about handbuilt CDIs. 
  Some of the looking around I did about CDI kits indicated that 100-150 Kv was quite obtainable with a handbuilt CDI.  But, you DO have to use really good insulation, ie: top grade silicon plug wires. 

  The thought about using injection for ignition of the gas was from this forum.  I have a large LP gas tank at my house , LP hot water, LP house heat, and soon LP cooking.  My city does have NG service, just not extended to my neighborhood yet. 
  I'll check out the CAT and Waukeshaw.

  The reduced wear and tear from using LP or NG was definitely a consideration.  From research done some years ago about conversion done to get car engines to run on LP, the target compression ratio was 12:1 for naturally aspirated engines. 

[fattywagonman]

Hi Bits,
I think the mini Petter is a great little engine platform with all kinds of possiblities.. I'm dong a similar project converting them to use propane or NG... for SI I plan to double the head gaskets to lower the comp down to about 14.. and use ethier high voltage with SB or pilot CI with LB..I if I go with SI I also plan cam mods to lower the EGT.. The gear pump could operate off the crank end and be mounted to the cam cover... I planed on running a magnetic coupled water pump from this location.... I got the idea from this engine..
http://www.marathonengine.com/ 

[Firebrick]

Cat natural gas engines are spark ignited, not compression ignited, at least anything modern.  They  use a spark plug and either a magneto or Computer system. 

[Firebrick]

Bits,

Lp is similar to natural gas which is methane, the same as diegester gas(although digester has acids that need removed).  Alot of the large hog farmers around have a generator that covers their electric bill that runs off the digester gas.  Some use an actual gaseous fuel engine with spark ignition but alot just add gas to the intake of a diesel to provide most of the power.   This has to advantages and without the disadvantages of an all gas fuel.  One is flexibility, the other is that you can still have the same power when needed by switching back to total diesel.  An all gas engine with have maybe 60-75 percent of the horsepower compared to a diesel built on the same block.  All you would need to do is place a fogger nozzle(an either nozzle, such as the used on large engines with small bottle that looks like a propane torch cylinder, works well)  pointing with the flow of air in the intake stream.  I would probably would want a longer air intake runner than is included with the listeroids to promote better mixing, but it might not be nessessary.  Place a small needle valve and a low pressure regulator between the fogger and gas cylinder and that is all you need.  This system works well with constant loads, once you have established a load, open the needle valve until the fuel rack closes to say 10 percent from closed.  If the load calls for more power the governer will add more diesel to pick up the load.  Need a full load on the engine, shut the gas off and let it run on straight diesel.

[Dail R H]

   I'de like to make a comment here. Years ago,I was doing some investigations into methane as an ae source. I found an article by a guy names "John Fry " from South Africa,a pig farmer who ran what appeared to be a Lister from the rather poor photo on methane,and just enoufh diesel for starting,and top lube. If I remember right,he used a valved line from the storage tank to the engine intake with some seel wool in it for a flame stop I think.
   Sorry ,I don't remember the source,but I think It all started from an article in MEN.

[rgroves]

   I'de like to make a comment here. Years ago,I was doing some investigations into methane as an ae source. I found an article by a guy names "John Fry " from South Africa,a pig farmer who ran what appeared to be a Lister from the rather poor photo on methane,and just enoufh diesel for starting,and top lube. If I remember right,he used a valved line from the storage tank to the engine intake with some seel wool in it for a flame stop I think.
   Sorry ,I don't remember the source,but I think It all started from an article in MEN.

I've been doing a lot of research on biogas ahead of my offering biogas digester components for sale.

The article you're talking about is at:
http://journeytoforever.org/biofuel_library/MENintvus/fryintvu.html

Take it with a few grains of salt. Mother Earth News wasn't usually concerned about getting all the details right.
And if anybody wants more reading on biogas methane, I have a load of links for you.

Russell Groves

[bitsnpieces1]

  HHHMMM, If you could set the diesel at about 10% and use the governor to increase/decrease the LP as needed!!!

Yes, NG gas is Methane ( CH4 ), Propane is a slightly heavier molecule ( C3H8 ).  I was thinking of using an LP carburetor (which isn't much more than a nozzle in a pipe) which could be set up to vary the volume of fuel itself rather than volume of air, operated from the Listeroid governor. 

OR perhaps a Petteroid would be better for this.

edit:  Steel wool (actually Iron filings, etc.) are used to remove the Hydrogen Sulfide that is present in straight digester gas, also would work as a flame stop.