Yes Kistijan,
That is the idea. I already have the old nozzles off and the restriction out. I was wanting to see if what I figured,someone else comes up with close to the same. A double check on my figures. Using the super dry wood and the insulated hearth there can be some variation.
Thanks, Ron L.
The marks circled are from previous builds not the one I am doing now.
Thanks,Ron L.
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Ha, l might use that trick someday do double check my wacky ideas 
Oh, and be sure to report your progress!
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Hi, Ron!
30.10.2018
Locally I have followed dimentioning of hearth volume
as a percentage of used gas consumtion per second.
It has to take into account the fuel size.
Or conversely, the fuel size âdictatesâ the hearth volume
percentage of the âsecond consumptionâ,
as the Germans would express itâŚ
(meaning gas consumption per second)
The fundamental hearth size percentage varies from small
âgrashoppersâ ~4% to 10 â 12% for 12 liter motors.
==========================================
An example:
Using a frustum calculator (on the net)
Volvo station wagon
2,4l 3000 RPM (open road, full-gas)
Fuel size: cigaret pack/2
Hearth size : 7% of the gasflow/s
L x n x 3 =
2,4 x 3 x 3 = 21,6 l/s
21,6 l/s x 0,07 = 1,519 l
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If you are going to do all that work, I would look for a Ford Triton engine with Variable Camshaft timing, that can advance or retard the timing on the fly using the PCM.
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Hmmm⌠hadnât thought of that. Sounds expensive and complicated regarding the computer. Getting into OBD-II scares me a bit!
Has anyone ever run one of these variable cam engines on woodgas?
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I donât think anyone on this list has. I should have saved the link. The timing is controlled by a pwm signal from the computer. It might be able to be adjusted with one of the aftermarket tuners if it doesnât adjust itself automagically.
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Hi Max.this is the volume of the gas flow, The hearth is considered the cone area from the restriction to the grate?
The 7% is the area of the hearth?
What are the factors that vary the hearth size percentage? Is it only the motor size?
I dont know how much fuel size would affect this but my fuel is close to 2/3 cigaret pack. 1.25 X 1.25 X 3.5"
To figure the hearth size will I need to figure in the additional blower volume ?
Thanks again, Ron L
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Hi,Ron!
1.11.2018
I was just writing a continuation to the VOLVO project,
and everything just wanished!
Back to fundamentals:
Originally people were talking about:
UPPER hearth and
LOWER hearth.
Later on, only hearth and (+) reductionzone.
So hearth today means original upper hearth.
With other words, with todayâs vocabulary:
From the nozzle-tip-plane to the restriction-hole-area
is calculated as the hearth volume. A cut cone (frustum)
(Internet has special calculators for that) Easy to use.
Correspondingly, the reduction zone (area) goes (when all
well calculated)
from the restriction down (and in some cases up again) to the grate.
Thatâs the general pictureâŚcalculated for max WOT and rpm power.
For the VOLVO gas consumption
L x n x 3 = 2,4 x 3 x 3 = 21,6 liter/second was determined, that
Cigarette pak/2 was suitable. It turned out to be successful in road trafic; 130km/h regularly.
On experiance the hearth volume varies with motor (gas consumtion) size.
From 4% in âgrasshoppersâ (lawn movers) up to 10â12%
for 10â12 liter motors.
On this Volvo 7% hearth volume turned out to be OK.
Hearth volume = 7% of 21,6 liter/second gas production.
= 1,512 liter hearth volume.
Drawing the slope of the âupperâ gasification hearth on checkered paper
(the moving/stationary part of the char),
you come practically right, if going 4 squares horizontally and 7 squares vertically.
(60,255 degrees)
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Hi Max, are you reffering to DJs volvo? I think its 2.3l not 2.4.
I forgot what the chart says on reduction zone volume. Culd you refresh my memory plese?
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Hi, Kristijan!
1.11.2018
I am not refering to DJ:s Volvo!
This is a local one! With re-enforced back suspension; this is allowed here.
And very much needed. Application taken from a station wagon Volvo model.
No charts (printed) have been followed, so I have to re-check it.
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yes, it based on the draw of gas through the hearth. The blower because it compresses the gas will increase the flow,volume of needed production by the hearth. If you are compressing say a 2.4l engine and doing a 100% compression by the blower, you need 4.8l of gas being produced by the hearth.
Hi Sean; what do you mean by 100% compression ? Would that be 17# of pressure ?
Atmospheric pressure at sea level is 14.7 lbs? But that would be a huge amount of boost.
compress it to half itâs volume. 100% isnât a very accurate or descriptive statement.
I donât know how much pressure that is. I was just trying to pick out an easy example.
Also keep in mind that compression of gases gives off a lot of heat. It is probably going to need to be cooled before entering the blower. Cooling it of course changes the volume as well.
The ideal gas law would be a nightmare to use, because of the mixture of gases, but you might get a rough estimate using a weighted avg of the component gas molecular weights. or just pick something like CO or CO2 and roll with it to get a ballpark idea.
https://www.engineeringtoolbox.com/compression-expansion-gases-d_605.html
Hi, Ron!
2.11.2018
To have full use of a certain compressor pressure, you also need an intercooler between the compressor (delivering warm mixture) and the motor. Too warm compressed mix does not bring in the wished for increased âenergy loadâ.
There is also the selfigniting risk hovering over your head⌠if you go too far without an intercooler.
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The ideal gas law is the simplest and perhaps most usefull equation in practical chemistry/phisics.
PV=nRT is the equation, R being a constante of 8.32. This equation aplyes to any gas or mix of gases, with reasonable practical accuracy. But for easy eyeball calculation, one mole of any gas at room temperature and pressure holds a volume of around 25l or 6.5 gal.
If you reduce the volume of gas in half and the temperature stays the same, you double the pressure.
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Thanks Gary; that is what I was looking for you are right 1 Atmospheric pressure is 14.7 psi not 17.
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Hi, Kristijan!
2.11.2018
to mess.50
The grate has full diameter = heart wall diameter, and is
1,5â2 times the restriction diameter below the restriction.
âSemiâ- toroid. Center can be closed. J-O:s and your principal.
This local Volvo is 2,3 liters too! It has now been driven
~ 18,000 km and the next one (in better shape) will inherit
the âgasplantâ now in december.
OK You can ask me on your own page, I will answere thereâŚ
Ronâs page!
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Hi, Ron!
4.11.2018
Last time I wrote, I tried to correct the fundamental concepts.
You did not have the patience to receive any proposal about the compressor application.
The starting point is an atmospheric condition with say 0,3m H2O underpressure on delivery.
The consumption formula I use aims at 72% filling. (from atmosphere)
L x n X 3
L = motor displacement in liters
n = RPM in thousands (rpm:1000)
3 = filling and mixing factors as well
as going from /minute to /second basis
boils down to this single digit
So, the end sort is: Liter per second netto gas.
Increasing the filling to 100% needs 28% more gas flow, theoretically.
(excluding increased resistances)
To achieve a filling degree of 100% with help of the compressor,
you need a flow area (and volume) increase in the gasifier of ~33%
Make the flow area (and volume) increase 35% to have âtrim-roomâ!
This affects ALL passage areas and process volume too!
Increase only diameters, not flow-lengths!
This will retain the same flow velocity as before.
(flow-volume : area)
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