Converting Diesels to woodgas

Koen has built a gasifier for a diesel truck

See “Building for big engines”

Hi, Kristijan!
4.7.2016
The compression ratio is a construction defined unit.
The available compression pressure tells the condition of the motor.

Max

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Indeed. Good reading Mr TT
Focus should be on understanding the diffnernce between an un-air restricted “trottled” regulated heavy fuel oil engine cycle; and a gasious/liquid fueled engine requiring precise air control to keep the mix in the needed flamabilty ranges.

Yes. Yes. I know. A long, complex, compound statement of facts.
Simpler.
Duel fueling a heavy oil fuel engine with woodgas can, and has been done.
The engine on this duel fuel mix will have a hybrid complex control system.
Have much poorer performance than an engine dedicated on either fuel exclusivly.
That duel fueled engine will have severe intake and exhaust back-firing and in-cylinder detonation problems under sudden varinig load conditions. Manual transmissions and heavy electrical on/off loading consumers - be HARD to manage.
Controlled loading applications as in pumping - possible. E.G, the 30 years India Institute of Science experneces.
And they finally gave up duel fueling compression ignition engines and just went with spark ignition engines from supplied by Cummins/India and others.

S.U.

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I think I read the papers Steve is talking about.
If memory serves the engine was KOEL RB-30.
This is triple cylinder clone of the Petter PH series ( pumped up a little )

If you go to the Arrow engine website you will see a modified DM-10 ( a single cylinder KOEL clone of the same basic design ).
That Arrow version has a natural gas carb and ignition system to burn well head gas.

I have a DM-10 and a crate of spare injectors, head, crank, cylinders pistons valves ( almost 3-4 engine rebuilds worth of parts less the block and flywheel )…
Enough for a lot of experimentation.
But the project never went anyplace
Here’s a page full of the engine variations ( I heard bad things about this builder however )

http://www.ashwamegh-india.com/petter-type-diesel-engine.html

Too any experimenter who gets his hands on one of these engines I have injectors and pumps if you burn a tip for just about any off the petteroid.

You know now that i am thinking about it if you are within driving distance of the nickel city, own a truck and are interest I will part with the petteroid, and an ST-5 generator head
About 800 pounds of material.

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Hello again KristianL
To help clarify some of what both I and MaxG are saying:
a diesel engine is operated completly air unrestricted. There is no air/fuel ratio.
a gasoline, propane, methane, woodgas fueled engine must have a variable air resticted flow to be able to instantly adjust the air-in allowed to keep these fuels into a combustion speed, managable air/fuel ratio.

Once you add in air throttling to a diesel engine you lose the adavantage of diesels not having engine pumping energy drag.

Those fumigating in propane and methane into diesel engines as a fuel supplement are delivering a refined pure gasious hydrocarbon fuel UNDER PRESSURE.

For safety reasons and system simplicity woodgas is normally engine drawn in under slight negative pressure. Turning a diesel into a suction engine will result in useable output power loss just like a clogged air filter.
People have speculate variable speed electric motor delivering woodgas to an engine. Not impossible. Just very complicated. And with woodgas another added in maintnece point. And a point of failure.
S.U.

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Steve; Here I am again. I always respond to your statements with much reluctance, because I think at times you think I am being contradictorily. That is never my purpose, I am trying very hard to learn. OK???

Once you add in air throttling to a diesel engine you lose the adavantage of diesels not having engine pumping energy drag.

Aren’t we talking about at WOT? Anything less we loose advantage by restricting the fuel flow through the injectors. I concede that air restriction will result in less volume of air in the cylinder with each stroke. But does that lower the compression ratio possible to the point the diesel fuel will not ignite. If it does ignite then the fact that we did not put in just air we added woodgas and the initial fuel ignition will result in an explosion of the wg that will give back some of the power lost.

When adding fuel supplements at a higher pressure— how much pressure are we talking about Tanks have regulators on them so it is not tank pressure. To be affective does the pressure/volume have to be able to exceed the vacuum/volume of the engine. Other wise does it have to be sort of “super charged” into the engine, or can it just flow into the air stream?

Final question. How would a two cycle GM diesel with a blower play into this?

Respectfully TomC

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Its not the compression ration so much as the cylinder pressure that matters.
You need to squeeze enough air at certain density to create enough heat for ignition with enough oxygen for complete combustion,

Some diesel operate just fine at 12:1 compression.

A turbo or roots blower in any diesel will allow it to regain full rated HP because it will draw in against the restriction and force the amount required…
Works the same for spark ignition too.

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Tom, a diesel engine is stratified and a gas engine is homogeneous. That is in regards to intake. I tried fueling a clone in stratified mode but didn’t have much luck. I did get it to run but that was about it.

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If l understand correctly you talk about a turbocharged diesel. The engine on the Golf is atmospheric. But l see what you are trying to say… how wuld the throtle work then? If l wuld throtle air/woodgas mix the pressure at the low throttle wuld be to low to egnite the diesel. lf l throtle the gas the it allsow wuldnt work.

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Hello guys,
reading all this new subject it came to my mind a video I saw several years ago of this brasilian guy. He made it out with no modifications as I saw in the video. Sense one of the things I want to do is use my future gasifier for multipurpouse and my generator is diesel, this chat is of much interest to me. I believe that this compresion ratio must have played some role, but this contraption, …WORKS!
This is the link that proves it:

Hope it´s usefull.

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What Wallace and JeffD said: answers.

TomC the Germans in their desparate days in WWII did woodgas 2-stroke marine/truck-industrial diesels. War measures to keep moving and fighting. Abandoned later. One operator forced cold gas run could tar up much I’ll bet. Detroit blower drives use a weakend quill shaft to shear and save the blower rotors and housing from s-h-e–e-t happens events.

Nice video AbnerV.
I cannot get audio on my currnet download location.
Gasifier appeares to be a Doug Willliams inspired design.
Definately shows the gasifier forced air blower dropped off while engine woodgas engine suppling. So engine must have an added in air trottle to produce the suction pulling through the gasifer hearth and filter train. Then pulling woodgas into the engine.
What he is labling as a “trottle” looks to go to the injector pump. So actually a speed/govenor setting lever for the diesel fuel.
Hard to see but the diesel injecton system appears to be an inline pump assembly type.

He shows genrated frequency and voltage.
Does not show electrical amperage or wattage loading of the system??
Now elctrical power a loaded electric motor. Like a saw motor. Then go on and off with that. Motor running; go on-cutting-load, to off-cutting-load. Then you will find the dual fuel balacing difficulties needed to be worked through.
These are well documented especially in the Sweedish Report on thier Scandia delivery truck.
It was thier agricultural tractor injector system suffered the injector tips overheating at full engine heat loading, but low cut back diesel fuel flows. They had to modify for additional diesel bypass flowing to cool the injuctors. Roostamaster, CAV rotory distribututed injector pump type as I recall.

Regards
Steve Unruh

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Gee, fellows. It was not my intention to stop all conversation on this topic.
Not my intention to be a seeming, know-it-all.
I DO read everything available on topic that I can get. Then use my real-world exprieneces to interpet what I read, or; would anymore video view.
I DID buy a 950 pound, BIG 1000 rpm single cylinder diesel with a variable compression feature with the intention of diesel/woodgas dual fueling for personal home power electrical generation.
Bought a smaller 300 pound 2600 rpm single cylinder diesel to be able to do the same.
Abandond both approches after reading/viewing results of others trying/doing and then stop doing; and the why’s-of-not-to, on these two engines.

So Why the off and on working load exhaust backfiring?
Mr Wallace answered that. For the quickest de-power responces the diesel fuel get govenor cuts back too quickly killing the “ignition”. At low, low diesel fuel loads; sudden in-cyclinder pressure changes can, and will snuff out the diesel ignition flame. Engine still rotating sucks in a few cylinderfuls of woodgas/air, pumped through, out into the exhaust, uncombusted. Diesel fuel then get increased to re-establish “ignition”. BOOM!! then into that fuel/air filled exhaust.
So Why the hard damaging backfiring up into the intakes?
Very lean gasoline, propane, methane, woodgas mixes have an unpredictable too fast of combusting speed which is vertually an explosion. Engine loads added as in big electric motors cutting in, or shifting up a gear, adds a “need-more-fuel NOW” before that fuel can be supplied. Fuel starved then, the in-cylinder mix is too apparent fuel "lean’ causing a too fast of pressure rise detonation in-cylinder then fast pressure waving backing up out into the intake manifold before the intake valve can mechaniacally timed close.
Hydrogen fueled engines have a severe problem with this. All attemts at “lean-burn”, “stratified”, HCCI, engines have failed out of the Labs enviroments into the real world to overcome this problem-set in any affordable way.

So the reason for much diesel and woodgas quick responce control compexities to be able to real world use/do this on a daily practical use.
IISc/CGPL documented this out on 30 years of trying from different approches very well.

The easy solution for the diesel “ignition” flame-outs was to just go to fully controllable spark ignition converted engines.
Then no diesel. Or, diesel fuel injection tanks, pumps, filters lines, injectors to have to feed and maintain. For India Rural or even India Industrial, sparkplugs and wires was a much less expensive to domestially produce then maintianing a petroleum import ruple draining Dragon dependnecy.
They just than compresion reduced to an all climate, all loads useage, 13/1 compression.
Woogas controls as commonly known used then.

KristijanJ. there are still two VW diesel pickup trucks still running around here locally. Resterant oil/grease fueled. No seed oils possible to grow in my climate.
Here in the USofA this era of VW diesels were actually gasoline engine block based. The blocks still have the means to add back in an electric ignition distributor.
With father-in-laws permission just reversable convert to spark ignition.
Double cylinder head gasket to reduce compression. Reversable modification.
Remove the on-engine diesel systems.
Use J.O.'s system build example and woodgas/CHARGAS the beast. Just get-it-done. Simple and directly.
Crow then, how you have better power and speed than a gasoline based engine.

Regards
Steve Unruh

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On the contrary Steve, your knowlidge (and others of corse) was most helpfull. The topic did not at all stop and either did my project. I am wery buissy in the summer haveing a full time job and a farm so l tend to absorb as much info as possible in the summer to start building in the winter.

That info on the block being the same is most interasting. There is a guy not far from me that drives a VW Cady , the old type that has moveable roof so its allso a pickup (talk about a great car for woodgas!) Anyway it is petrol engine so l can compare it to ours.

What do you think of the other diesel drinker, Deutz tractor? Its three cilinder, if l remember correctly its about 45 hp. The plan is to build a wood gasifier that culd be hooked in front of the tractor. Set the hand throttle to a high idle on diesel and hook woodgas on it, restricting it a bit with a valve. The engine wuld thain run at constant 1600 rpm for a log spliter. The rpm wuld be set by the restricting valve. I think the valve shuld be closed just a litle bit becouse the engine has that 1600rpm on about 3/4 throtle on diesel so if i put the power drop of woodgas in to count i think i can still get enough gas in the cilinders to not loose to much compression. What are your thods? Injectors overheating?

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Hi Tom,

As Steve’s point is true, there is no throttle control in a pure diesel engine, no changing restriction to take in account to calculate mixtures. So, with other words, always WOT.

Second thing to take care of if rebuilding a diesel into a 100% gas engine:
There are no valve oil seals installed, so creating a vacuum by installing a throttle, will cause some un expected smoke/oil consumption.

As Steve mentioned, controlling a diesel based engine to run on woodgas is do able, but also a bit more cumbersome then using a pure gasoline to gas engine.

Been there, actually i am there and i am doing that…

Kristijan: learning by doing and then doing it again untill it breaks. Finding out the limits is the biggest fun…
But always remember: put a decent load on the engine…
Tip: measure your exhaust gas temperature to get some nice info… and build a feed back control towards a slightly presurised gas control valve…

Edit: with throttle control, i mean an actual valve controlling the airflow…
The rpm control is by the amount of diesel injected in the engine combustion chamber…

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That sure is true :wink: finding out limits and goeung past them.

The part for the decent load is tricky. The engine is only rotating a small hydraulic pump, maybee consuming about max 5kw worth of power, almost 0 when it spins free.

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Hi Kristijan,

The 5 Kw hydraulic would do fine for testing, just not let it run free :grin:

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Sorry I do not know the aircooled? Duetz diesel injection systems well enough to be able to advise.
Rare, rare here in the US. Primarily used only in mines here.
S.U.

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FLW*912 is probably the most common one.
Pre-cup diesel very clean for its time but not well suited to dual fuelling.

They had an agreement with KOEL in India to make clones.
The Indians drove Duetz out of the asian market when the agreement ended.
They sell those clones and they are great engines too for less than you can get a rebuilt.

After much thought if anyone wants to entertain a an offer on the Petteroid I am ready to let it go make me an offer.

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i have a few old 1985 6.2 chevy desiel motors i would like to run on wood gas. Is there some way too tell how thick of a head gasket spacer Too reduce compression back around 12 too 1 compression.? Or would one have too measure with liquid voluem, the differnce between the two compression motors with same size bore.?

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Hi Kevin,

1: do you intend to run on woodgas only or dual fuel ?
2: if you strip the head down, i can calculate , if you do the liquid…
3: any tech data on hands that i can look into ?

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