It has been rainy these days and the air has cooled down, the ground is nicely soaked, well, that is not suitable for working with a tractor. I took advantage of this to clean the gasifier, as it has completed 80 working hours since the last emptying and cleaning (in the gasifier service instructions, such an intervention is foreseen after 50 working hours).
That is looking great Tone
It seems very dry and ash-grey, it must be your gas preheating the wood working well.
In my gasifier i have only the hot gas going up to right above nozzles, and there i have a “collar” of tar and chunks. No problem for me, it collapses from time to time.
I burned down the wood to nozzle level yesterday, and had a great opportunity to snap a pic of the collar, but forgot
Otherwise burning down that low is healty, the tar collar becomes crusty of the radiation heat, and becomes fuel after next filling. One should have in mind to run it hot enough after a burn down, because there is always a risk of tar then.
Great work, i never get tired of watching your tractor work, i need to get my little Fergie taste woodgas soon.
Thank you Goran, it’s nice to hear your opinion, the opinion of an expert in the field of wood gas, it means a lot to me and says a lot, … When I post such pictures, comments and opinions are always welcome, this is how the systems are improved, or the process of use. I remember when Mr. Steve commented on the process of gasifying wood and what remained in my memory was …“the conversion requires temperature and time” … and Mr. Wayne … “I dry the wood when the car is standing still”, … Thank you all for the good advice.
As I mentioned above, it is very important to consider the following when using a wood gasifier:
drying the wood in a hot atmosphere (when the gasifier is at rest), whereby initially the moisture comes out through the chimney at the top, then condenses on the lid (usually about 1-2 liters of very clear water are formed
the chimney for releasing steam is very important, that it is placed at the highest point and so that the condensate flows into the collection chute (the current setup at Fergi does not meet the first requirement)
An important factor to this internally drying of wood process is the size of the system.
The size of the system determines how much HOT internal Mass (heat volume) you will have to work with.
Why Micro and Mini systems always insist on only having very good pre-dried down woods inputs. Or they become tar-making babies.
The critical line I have found is a system that will use up ~3 kilograms/10 pounds of wood an hour.
Or as Ben Peterson found: a system fuel gas suppling an IC engine greater than 500cc / 30 CID. Better . . . easier yet, 1000cc / 61 CID.
Some boring pictures from this afternoon, I have nothing more interesting to post. Fergie crushed about 5 m of gravel and used a little over 10 kg of wood,…
I prepared some sand, about 15 m3 this afternoon, Fergie used two bags of wood, constant load about 15 kW, I’m starting to doubt that he uses less than 1kg of wood for 1 kW hour.
This is what it looks like, if you sit on the arm of the excavator,…
Joep, I have a feeling, when I monitor the operating time, wood consumption, engine load, that it consumes LESS than 1 kg for 1 kWh produced.
I will provide some data:
The 2.4 l engine operates in a vacuum of -0.15 to -0.20 Bar, which means that the load is 80-85%, or 100% of the load of the 2.0 l engine
The engine operates in the range of 1300 - 1500 rpm, which means that according to the data on the capacity of the engine on wood gas (engine with a 1l working volume, at 1000 rpm … produces 5 kW of power) it actually produces 14-15 kW of power
Yesterday it worked like this for more than 3 hours with minor breaks, and it consumed about 25 kg of wood
I could never have imagined that I could do so much work with such a “small” amount of wood.
Hi Tone, this is interesting, others had find lower consumtion numbers too, in many older and newer publications, i’ve seen it too.
In some older tests they quenched the gasifier with co2 extinguisher to avoid any “after burning” to calculate the exact amount of wood used.
It seems a gasifiers efficiency is “variable” and under certain circumstances transfers up to 90-99% of the woods stored energy to useful gas, (im not surprised your well designed gasifier is top efficient.)
There is also other chemical reactions, that helps up the energy of wood gas, from better methane production, and ofcourse the precious h2.
I think we have to re-valuate typical wood stored heat energy…
Lately I’ve been working on adjusting the ignition timing (pre-ignition). I have a Suzuki Maruti distributor on my Fergi, which is equipped with a centrifugal and vacuum regulator, which change the ignition timing. The Suzuki distributor is designed for a high-revving engine (up to 6000 rpm), so the centrifugal regulator does not significantly affect the ignition timing, but because the Fergi engine reaches a deep vacuum, the vacuum regulator changes the ignition timing a lot. Now that I have a vacuum gauge in the intake manifold, I can see that the vacuum regulator is not working optimally. The ignition timing starts to increase at 0.1 Bar and at about 0.3 Bar it reaches its maximum deviation (it shifts the ignition by about 30°, maybe even more). What’s going on? If I set the distributor so that the engine has max torque at full throttle - 0.1 Bar, then I hear knocking at 0.2- 0.3 Bar, but if I set the ignition for vacuum 0.3 Bar, there is no real power at 0.1 Bar. I will try to replace the spring in the vacuum regulator, so that the operating range would increase slightly (0.1 -0.5 Bar)…
So you don’t get any knocking at full throttle but you do knock at lower rpm?
I know they had problems with swirl chambers, and pre-chambers with knocking, in my books.
Jan, I want to say that this vacuum regulator operates in too narrow a vacuum band, which does not satisfy the optimal ignition advance setting for a wood gas engine.
Wood gas is no joke, it is a powerful fuel, but it has its own characteristics, to which we must adapt the engine’s operating mode.
My intention is:
to change the effect of the centrifugal regulator, which must operate in the range from 800 to 2500 rpm (in fact, the distributor rotates at half speed and this must be taken into account)
to change the effect of the vacuum regulator for the range from -0.1 to -0.5 Bar
I find that the engine reaches maximum torque - power when it operates at the knock limit, well, the ignition distributor must provide this in all operating ranges
At the moment I cannot give exact data on the ignition advance angle, which is measured in degrees of the main shaft position,…
According to experiments and a rough estimate, an unloaded engine (vacuum pressure -0.5 Bar) should have at least 30° of ignition advance at low speeds (1000 rpm), which would increase with the speed, so at 2500 rpm it would increase to 40°. A fully loaded engine (vacuum pressure -0.05 Bar) should have ignition at 1000 rpm 5° - 10°, which increases with the engine speed and reaches at 2500 rpm approx. 15° - 20°.
I may be wrong, please correct my thinking (Mr. Wayne, Goran, JO, Jakob,…)
Hello Tone
On the for-gasoline distributor ignition vacuum timing advance the typical advance is INCREASED by higher manifold vacuum as a fuel use economy device.
At a normal naturally aspirated engine loaded condition the manifold vacuum decreases so the timing is NOT vacuum control advanced so as not to created pre-ignition/ pinging.
Now just to add confusion it became commonplace to have dual motion distributor vacuum controls with two input source lines.
One side to advance for fuel use economy.
The other side to pull back advance to prevent in cylinder high pressure made nitrous oxides emissions. The control source for that actuation somewhere under the edge of the throttle valve.
The internal springs centering. The two vacuum sources overriding each other at different made conditions.
Some actually did not pull for actuation - but pushed.
Ha! Ha! I’ve in vehicles hand pumped for on the fly changes - economy challenging.
Or used a vacuum can (like for old windshield wipers) with tubing and little plastic aquarium valves to timing trim for quick jaunts up into our mountains. This on emission feed back carburetors to on-the-fly driving enrich; or enlean.
You bet. Get creative. For response of changes you may have to increase the diameter of the diaphragm area. Look at natural gas control valves. Or propane control valves.
Regards
Steve Unruh
SteveU point out some good stuff here.
Timing advance / vacuum advance/retard could easily be mixed up, easy to think in the wrong direction, there are some different systems out there, where the 1980s systems, exhaust control, is the worst. As SteveU points out there are “double vacuum” systems, and a variety of places where vacuum is “taken” under carb=normal inlet manifold underpressure.
In venturi: more vacuum when throttle opens.
Special “pitot” tubes=more vacuum with more flow.
And worst: combinations of two or all three of these, controlled by electrical, thermo, and other types of valves, and vacuum modulators. Sometimes a distributor which looks the same, only one number in serial difference could work totally wrong. There are Bosch distributors, fitting, looks exactly the same, where vacuum advances in one, retards in the other, just by how the diaphragm link is placed. (Been there, done that…)
And progressive vacuum regulators… looks the same, just a little elongated cylinder between diaphragm housing and the dist. this cylinder contains another spring, and a plunge piston, counteracting the diaphragm.
A real “djungle” of things to take in acount.
I once got a classic distributor tester from a shop school, i gave it away to a “racing” guy, because it took to much space, i really regret it today…
SteveU may remeber these? A “box” on four legs, with a round degrees scale, adapters and holders for different distributors, and a special scope where one could read out advancing/retarding at different speeds, and be able to shift springs in the centrifugal advance, and see results. There was a hand operated vacuum/pressure pump with a gauge for testing. And about 6 or 8 heavy binders with settings for various distributors.
Ofcourse this could be done with a good timing light, a 360° protractor disc, and tachometer and vacuum gauge.
Yep. My professional experiences too Goran.
In the mid-1970’s as an early 20’s something I got my first job in a true full service auto electric company. They were still using a top of the line SUN brand classic distributor machine. For decades the best of shops for premium tune-up’s it was remove the ignition distributor from the engine; clamp it in and spin it up strobe light checking the mechanical and vacuum advance curves against charts. Then rebuild or replace the distributor.
Problem. We could no longer get the parts to repair or rebuild. The “remanufactured” units would often test worse than the original take-out unit.
Became a relitvley unimportant then. The challenge was trying to sort out the many control lines and inline vacuum delay valves affecting engine drivability. Nothing was position polarized. ONE reversed little bi-colored in-line valve could ruin your day.
Then the thing became expensive engine analyzer machines. Lots and lot of probes; sensors; hoses and lines to hook up for a menu directed full spectrum diagnosis of state of health.
Service was too time consuming and expensive. Folks did not want to be told bad news. They just wanted their vehicle to run like it used too. And that was not a woo-woo tech-solve. But a manual clean, adjust . . . sometimes by-pass . . . always a make-work any which way. Legal or not. The big expensive analyzer machines got pushed back into corners collecting dust. Hand-helds gave you the to-the-point specific, that you needed.
Past a low $$$ in repairs and here USA they’d just go out and finance a newer vehicle anyways. You never, ever got the pay for diagnostic. Only component replacing.
Ha! Ha! I am so American. Aged into my 40’s after ONE tow back home I am done with that vehicle. Don’t want spend any more time or money into it.
S.U.
I am attaching a link that talks about the ignition distributor, but all these ignition systems are adapted to engines that run on gasoline, but we need such a system adapted for the “engine fuel” wood gas or charcoal gas.
We can see that the ignition distributor has about 15° of effect with the vacuum regulator and 15° with the centrifugal, so a total of 30°. The question is, is this enough for wood gas? According to the reports I have read here, this is not enough, because some of you (Mr. Wayne) have a system installed for manual correction of the ignition advance while driving, which is controlled from the cabin.
To summarize some facts:
I have an ignition distributor that changes the ignition angle by 30°, if I know that the engine does not reach more than 2500 rpm, then this angle of change is probably sufficient and will meet the needs of “wood gas”
wood gas can withstand slightly higher temperatures during compression compared to gasoline, so the CR of the engine can be up to 1:13, but at this compression pressure the temperature of the gases rises very much (more than 400°C), well, such a mixture of wood gas and air should not be ignited too early, as this causes a rapid increase in temperature and pressure, which triggers detonation (to approx. 500-550°C) … this means that the ignition must be carried out almost completely at the top (5° - 10° before the top), when the engine is rotating slowly and the vacuum is -0.05 bar
when the engine starts to rotate faster, the throttle is at max, it starts in the vacuum in the suction line increases (resistance of the gasifier, gas cooler, filter,…) and at 2500 rpm it is approx. - 0.15 bar, in this state the centrifugal regulator should increase the ignition angle by ?? (10°) and the vacuum regulator by ?? (5°) is this enough?
the vacuum regulator must operate in the range of -0.1 to -0.5 bar and proportionally change the ignition angle by 15°, is this good for wood gas?
