Project for a 50HP wood gas tractor

Projects
#1

Hi!
I want to build a wood gas generator for a 50HP tractor.
I want a refractory burning chamber.
Here a few sketches:

thickness of refractory layer 2"-4" ?

I need yours help for a dimensions,please.

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#2

What is the cc or ci. HP does not mean anything on a tractor.

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#3

John Deere
5045E
Utility Tractor

Engine description John Deere PowerTech 3029
Engine displacement 3 cylinders: 2.9 L, 2900 cc
179 cu in.

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#4

This sounds like a diesel engine. Is it? TomC

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#5

http://www.tractordata.com/farm-tractors/005/7/8/5789-john-deere-5045e-engine.html
Good call according to tractor data it is a diesel. Also a pretty new one start of the model is 2008. I suspect the compression ratio is probably too high for wood gas not to mention the lack of an ignition system.
There is a good thread on here somewhere where Chris talked about the max compression ratio for wood gas to avoid pre ignition I want to say the cut off was 19:1.

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#6

it looks like a turbo charged engine, low compression , very suitable for full conversion…
max CR should not exceed 17:1

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#7

I would have to see the manufacturer data on the compression ratio. My case 5240 is a Cummins diesel with a case head on it. They both turbo charge and super charge that tractor but the base model has a 19:1 compression ratio.

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#8

The CR is 17.2:1 according to this, which might be slightly different.

There are some minor differences between the industrial and the one in the tractor like wrist pin size, but I don’t think it will matter for compression ratio. They also made a naturally aspirated version.

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#9

can someone explain why wood gas can withstand a compression ratio of 17/1 in a diesel engine and only 9/1 in a petrol engine?
Thierry

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#10

Euh… it can withstand 17/1 … but there is no petrol engine that can run at 17/1 …
But if you boost with a charger you can reach that in a petrol engine :grin:
Don’t ask me what will happen in a standard petrol engine if you do High CR with woodgas and wrong timing…

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#11

Trigaux; look up the meaning of “octane”. My interpretation is; a rating of a fuel’s ability to with stand high compression compare to a base or standard fuel. Woodgas generally has a higher octane rating than gasoline so it can take more compression before detonating or we refer to it as “pre-ignition”. Diesel has a higher OR so it takes more compression to cause it to detonate, which is the source of ignition in a diesel engine. My understanding is woodgas has a higher OR than even diesel, so to run a diesel engine on woodgas you have to add a small amount of diesel to cause some per-ignition, which as I said is THE source of spark for the engine to run. TomC

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#12

I had a Yanmar that had 23:1 compression but I read somewhere that wood gas was good to about 16:1 maximum.

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#13

Yup, Just think of the octane numbers you see when you fill up at the pump in the US: 85, 87, 92. Now think of the compression ratios you are likely to find in engines out there: 8.5, 8.7, 9.2… Can you see a relationship between the two sets of numbers?
Rindert

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#14

Don; The word “good” is kind of a two sided coin. In a gas engine we do NOT want the gas to pre-ignite before the “spark” so woodgas is “good” up to 16:1 as you say. But in a diesel the ignition of the cylinder is relying on the gas self or pre-ignition. So wood gas will not act alone until a compression of much MORE than 16:1. That Yanmar tractor should have been “good” with woodgas and NO diesel (I think). TomC

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#15

Hi Tom!
20.2.2020
It seems you are dribbling yourself: A diesel motor ignition is not a “nock” or detonation of a readily precent air/gas mix, but a “peacefully” proceeding combustion , ongoing during the injection phase. The diesel liquid-fog starts the flame-point.

No motor works well if the only source of ignition is detonation.
Nice rolling needs a “point ignition”, be it a spark or nozzle-blast.
Max

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#16

Good day Max.If I accept your premise;

Then I ask, will the liquid-fog burn if the injector sprays the liquid-fog into the open atmosphere?
I have seen injectors tested by spraying into a glass chamber to inspect the spray pattern and there was no flame created. TomC

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#17

Hi,Tom!
20.2.2020
A somewhat odd retorical question!

It should be obvious, that the temperature rise during the compression stroke is dependent on the intake temperature and the compression ratio (as main factors).

The ignition temperature-gap between the diesel “fog-clowd” and the selfignition temperature of the woodgas/air mix are normally maintained at a safe distance.

Max

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#18

Oh Max; Here you and I go again bumping heads.
“the temperature rise during the compression”; “The ignition temperature-gap between the diesel ‘fog-clowd’”; and “woodgas/air mix are normally maintained at a safe distance.”
Is the temperature “maintaine” or is it we have never built an IC engine with a compression high enough to run on a strictly woodgas/air mix. We at presant always have to add a dribble of diesel fuel to produce the ignition. TomC

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#19

Hi, Tom
20.2.2020

I have simply tried to define the temperature rise at each kompression stroke.
The compression heating temperature has to go over the diesel-fog ignition level, but not
over the gas-air mix self-ignition level.

That for Diesel motors.

Is this acceptable?

Max

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#20

Max; I will end this now; I see your point that the diesel fuel burns in and expanding pattern as it comes out of the injector into the very hot compressed air in the cylinder. Accepting that leads me to wonder “what would happen in a diesel engine if the timeing was set so the fuel would be sprayed in just after INTAKE valve was closed? I’m sure it would not burn at that point with out the hot compressed air that comes from the commpression stroke. But would it ignite as the compresson stroke heated the air ( such as gasoline does when the spark timing is retarded and we get ping or preignition?” TomC

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