[Edit]
Parts ordered:
-LCEngineering street stroker kit and 30-pound high-torque flywheel.
-DUI Short Version Distributor with Vacuum Advance.
-LCE Pro Oil Pump and Adjustable Oil Pump Bypass.
Other parts built, used, and modified:
-20R head ported and lapped, on a 22R block.
-Single-row timing chain swapped to dual.
-Corolla carburetor modified to deliver vaporous fuel.
Remaining parts to build and install:
-Necessary plumbing for fuel delivery.
-Fuel filter system; condenser, byproducts collection tank, steam delivery system.
-First model gasifier unit for first operation.
Post-functional touchups:
-Build second thinner style gasifier pictured in this thread, an electric fuel pump, and an exhaust gas energy conservation chamber around it, to increase efficiency and performance.

[End edit]

My production of a wood gas powered Toyota truck, which has been several years in the making (which I posted about several years ago) has finally received enough funding to be built. Much R&D on this subject has had to be done, which is where I've been with it since I posted back in '17. Since then I have made some modifications to much of the system. I'll post new images and details as the build develops, starting now.



I've lapped the original valves on this, but oversized valves shall be installed in the future. Oversized valves are an obvious choice, however I cannot allocate funding towards that at this time.



Intake runners have been ported to gasket size. The low potential energy of the gas requires the least amount of flow restriction as possible, which is why I have chosen a 20R head for this project.

The reduced volume of the combustion chambers in the 20R head lends itself well to the function, as the high octane of producer gas (I stated in an older thread 105, but it is actually above 120) means that an engine built to run off of the gas should have as high compression as possible, as the ~30% power loss in an engine converted to producer gas can be mitigated by increasing the compression ratio and improving the flow of gases through the cylinder head. The optimal compression ratio for this type of fuel is 11:1, and any modes to achieve that ratio should be taken in order to compensate for the power loss, or perhaps even increase the power output beyond usual gasoline burning. Though it takes a lot of engineering in itself just to meet stock power output; it would be foolhardy to expect to exceed stock horsepower, but it is a possibility. I have used here the electronic fuel pump equipped version of the 20R head, as I will not have to block off the mechanical fuel pump port.

The 30% power loss with producer gas, the 11:1 optimal compression ratio, as well as more data I will be mentioning in the future, are taken from "Wood Gas As Engine Fuel", published by the Food and Agriculture Organization of the United Nations.

Further updates coming soon.

 

Is this for the truck or the Delorean?

 

This is for the truck, unfortunately I can't figure out the time travel part.

 

Current work on carburetor. Donor is 20R carb.


Cutting out of the divider wall between the float bowl and 1st barrel. The gas will be inlet through the port which is cut out for the float window. I will have to build a one-way valve for gas inlet into the second barrel in order to eliminate reverse-flow under choke, so that air cannot flow through from the second barrel into the first while the choke is being used, as 20R carburetors only have one choke butterfly on the first barrel, and no choke on the second.



Jets, valves, the float, and all other gasoline metering devices have been stripped from the carburetor, as they will no longer be needed. The two vacuum lines going to the distributor advance will be the only vacuum lines remaining on this unit. The only other rubber hose will be from the PCV valve.



There is a restriction in the barrel, and I do not know its name but I know its purpose. I will refer to it as a "Venturi Sleeve" in reference to the principle on which a carburetor operates. It is in place to increase air speed around the jets, and this fluid dynamic is called the "Venturi effect." The entire system; jets and barrel, (and in this case, the sleeve) is called a "Venturi." Due to the new system, this part is no longer needed as it will only serve to restrict flow. It is an aluminum sleeve and is being removed here which will add nearly a half inch to the diameter of the barrel.


There really isn't a way to remove the sleeve without destroying it.


The baseplate containing the throttle, which is an iron piece on the 20R, is of slightly smaller diameter than the barrel when the barrel is missing the Venturi sleeve. I am tapering it here in order to relieve some resistance to flow. This will require some widening of the through-hole in the baseplate gasket. Ideally the entire bore should be widened, along with the bore in the intake runner, but this is something I will have to leave for the future.



Next-day addendum:



The gas inlet port must be widened and polished. The gas inlet port should be of about the same size as the carburetor barrel itself, as this type of gas run in an engine should be at a 1:1 ratio. A slightly larger gas port is preferable to a smaller one, as the air/fuel ratio can be leaned out by a fuel line butterfly, but if one were to have to richen it with the choke it will reduce max CFM, which will rob the engine of power.

 

Carburetor modification continued, now with simplification!



There's a whole treasure trove of garbage bolted onto the front of the body which is reminiscent of a scope on an AKM. All of this has got to go in the name of progress, but the throttle return spring is also located on this side, and that needs to be retained. The plate which the spring pushes against also has crap attached to it, and there is no use for diaphragms to modify idle speed in the absence of air conditioning, nor the need for a plunger which fights against the manual choke cable.




Time to cut some things apart! I need the backing plate for the return spring, but not the diaphragm. Both of these diaphragms are good, and they're free if anyone needs them.



The piece I need, newly divorced from a piece I don't. After some filing, because I should shoot for at least some amount of quality.



Throttle spring arm and associated parts, sans diaphragms, before and after usefulness upgrade.



Carburetor front parts reassembled. It runs a lot smoother now that the unneeded parts have been removed.

That's all for now.

 

It's time to remove the choke and other components. It's a bit odd to see a 20R carburetor with an electric choke control, but then again I had an '83 22R with a water choke. 81-84 was a bit of a transitional period for Toyota engines and they had a little back-and-forth going on with parts in their base models.



This choke is in rather good shape, it's free if anyone wants it.



Taking off the backing plate too. I've always had trouble with the JIS screws stripping out, and it probably has something to do with me not having JIS screwdrivers. My solution has been to cut a notch in them so that I can put more leverage on them with a common screwdriver, and they almost always work with no problems after that.



One of the choke valve control points will be used in this conversion, the rest will not. This is before and after bending it, as it will have to be installed backwards in order for it to swing back and forth in the proper directions and angles, and the arm has to be on the far side from the carburetor body. This does put it into a position that appears like it will be in the way of the air filter pan, so I may need to do some more modification later.



With choke valve removed, its axis is to be modified. This is a before and after image, with the circlip being the only remaining part on the end opposite of the choke control mechanism.


Pin pliers are one of the best things anyone ever came up with as far as these little clips go.


With the choke and parts removed, other airflow-restricting pieces on the inside of the body are removed. This is not the correct tool for this job but it's the tool I have.



Through-view of the carburetor after it has been a little more streamlined. I was hoping for my craftsmanship with this piece to be a lot better, but I suppose poor tooling yields poor results. I'll come back and polish this all up when I care.



The idle step-up is ground into a camming surface, so the idle speed can be controlled from inside the cab. This is because the contained energy of certain gases can vary due to what kind of fuel is being burnt. One type may produce a smooth idle at a certain adjustment, and another may cause the engine to die or rev too high on the same setting. The idle screw will be used to set a baseline, and the new camming surface which is cut into the former idle step-up will be controlled from within the cab via a cable on the same principle as a manual choke. When i get some fine sandpaper I should come back and polish the surfaces, as I can feel the grit of the filing work when I turn the mechanism. A good polishing job will go a long way to smoothen it up and give the operator finer control. It is perfectly functional as it is, but one should always try to make things nice.



A notch has been cut into the high end of the idle adjustment cam, so that the cam cannot be turned too far and swing into the mechanism to jam it. The notch must be cut with an angle at its inside edge, so the idle control arm which it interacts with can be cammed out of the notch. This design is due to me simply not having enough material to work with. I would have preferred to have a protrusion on the end of the cam to stop it instead, because due to having to add the notch the rest of the camming surface must be cut at a steeper angle. Once this system is installed and is being adjusted, the baseline idle is set with the regular idle screw, and then the high idle adjustment screw is used to adjust the idle-up system until the idle control arm just barely comes into contact with the camming surface when the cam is at its lowest setting. This is so that the entire range of the idle-up mechanism can be used. Pictured above is the regular idle screw set to an abstract position, and the idle-up system adjusted in approximate proper accordance with it.



The high idle kick-down arm, which protrudes upward from the right of the high idle adjustment screw, has been cut off to prevent throttle use from interfering with the set position of the idle speed control cam. In original configuration, quickly depressing the throttle pedal to the floor and then releasing would cause the kick-down arm, which is attached to the throttle axis pin, to rotate around with the throttle and hit the idle step-up, causing it to rotate and release the idle control arm, thus turning off the high idle. Since the new purpose of this device is to adjust the idle speed, throttle usage must not interfere with the setting throughout its entire range.

 

I have some more work on the carburetor to do, but for now, I have some information to spill about my bottom end parts. It's not new information how a bottom end is built, so I'm not going to go into exquisite detail explaining it. However, the bottom end will be modified, and it's important to explain why.


This is the LC Engineering 22R street stroker kit. It came with the 94mm overbore pistons, H-beam connecting rods, and all the works. As they said in the old school: "there's no replacement for displacement," and that is especially true with producer gas. Beyond the power gains from more displacement, however; it is important to note that producer gas has a lower laminar flame speed than a gasoline mixture. The leverage advantage and thus torque increase resulting from the extra 5mm of stroke will be a big benefit for the less powerful producer gas mixture, but this isn't the most important reason for doing this modification. The most notable advantage, unlike in an engine which will still be fueled by gasoline; is the moving of the engine's power band into a lower RPM range as to make it more suitable to the lower laminar flame speed of the gas. This stroker crank will be combined with an overweight 35Lb. flywheel, in order to make these advantages even more profound.

The forged aluminum pistons and the H-beam rods supplied with the street stroker kit are not at all necessary for this motor, and all these parts are quite a bit overbuilt for this purpose, considering that the load on those pieces will be lower than in a stock gasoline 22R. However, LCE is one of the few companies that offer these kinds of parts, and is one of the fewer that offer them with good build quality, which is why I chose their kit. Even then, I won't be complaining about stronger components.

 

The device which I have nearly completed building from the 20R carburetor cannot be properly called a 'carburetor,' as a carburetor operates via the Venturi effect, and this device no longer does. Due to the nature of producer gas having to be kept entirely isolated from air up until the point it is mixed with air in this device, I have dubbed this device a 'Desegregator.'



What was the float bowl window is now widened, to be used as a gas inlet port instead. I am hoping to be able to use the supplied screw holes to attach the piping easily, but I fear that this port as it is will be too constricting, and if I find that it is, I will have to come back to this and widen it.




The end mill bit that I just bought today is already coming in handy. Slots are cut in the gasket surface for a baffle which will be made of sheet metal, which will serve as a regulator in the second barrel.




A slot must also be cut for the one-way valve. The baffle is made into shape and bent, so that the edge of the end which slopes down into the barrel is roughly in line with the centerline of the bore, as an approximate 50/50 mix of gas and air is needed. The slope angle should not exceed approximately 45°, and if that means that it does not line up perfectly with the bore centerline, as in this case, it can be compensated for by removing some material from the end of the baffle, as pictured at bottom. A T-shaped flap, serving as the one-way valve, is placed beneath the baffle. The one-way valve is opened by vacuum, and when the choke is being used; is closed by vacuum, and so does not have a spring and must dangle freely. The baffle is necessary to ensure that the fuel/air mixture in the second barrel maintains a 1:1 ratio, as the one-way valve and smaller size of the fuel intake port vs. air port will add resistance to the intake of fuel. Since the fuel must be mixed at a 1:1 ratio, using a baffle to block off 50% of the barrel from drawing air does not serve the function of a choke.




The air baffle that I cut was not long enough for the top of the desegregator to seal against it, and so I had to cut a relief to put in a blocking plate. If I were to do this again, I would make the baffle and blocking plate as one piece. As the baffle is, air is freely able to bypass the baffle and one-way valve when the first barrel is choked on startup.



A top-down view of the barrels. The blocking plate can be seen covering the spot where the baffle was cut too short and air was able to bypass the valve. Below is a view of the one-way valve through the gas inlet port, both in the closed and open position. The valve should be able to be opened and shut by gravity alone by gently rocking the desegregator back and forth. It is not necessary for the one-way valve to seal perfectly, only for it to provide enough resistance to airflow that an adequate amount of gas is pulled in instead.

 

Wow. Very thorough knowledge on these carbs!
What kind of wood will you be burning?

 

Of note: the correct term for a choke plate or throttle plate is "butterfly valve" or simply "butterfly." When I first wrote this up I kept having to use terms like "first barrel throttle plate/second barrel throttle plate." That made everything long and complicated, so I'm editing this and will instead use the terms "1st/2nd butterfly." In order: the first barrel and first butterfly are the smaller ones, and the second are the other ones. I have also been using terms like "throttle plate axis/butterfly axis," this refers to the rod which they are screwed onto, which opens/closes the valves.

The vacuum diaphragm which controls the second barrel's butterfly valve on the 20R carburetor is controlled by the airflow passing through the first barrel, via a port which is drilled through the side of the Venturi sleeve, about halfway down the barrel. The basic principle of this is: any barrel has a maximum flow ability, caused by its diameter, which is measured as 'Cubic Feet per Minute.' When this maximum is reached, the engine will continue to try to accelerate, but since no higher volume of air can be achieved, vacuum will increase in the barrel. This vacuum sucks air through the port, which activates a diaphragm, which opens the second barrel's butterfly accordingly. The purpose of the driver not having direct control over the second butterfly is as follows; a larger barrel in a carburetor results in irregular jetting of gasoline and unreliable power at lower speeds, which causes engine stalling, inefficiency, and low power output. Toyota's solution was to make a small barrel next to a large barrel, the smaller barrel providing more even gasoline flow at lower speeds so that the vehicle can have more low-end torque, so that it performs better when being used for 4WD applications as long as only the small barrel is in use. If the vehicle is being used at low engine RPM and the operator suddenly opens up the throttles all the way, opening the second butterfly as well, the vacuum on the jets can drop so suddenly that the flow of gasoline through them stops, which will cause the engine to stall. This problem was solved by taking the control of the second butterfly away from the operator and instead controlling it with vacuum. Toyota's engineers designed it so that vacuum in the first barrel in excess of the amount of vacuum needed to pull the first barrel's maximum CFM will thus open the second barrel's butterfly proportionally. This nature of varying intake vacuum is the same reason why Weber carburetors, among others, have to be tuned to a higher idle speed, as well as why they perform better on the highway but can sometimes be lacking in their off-road performance. Many other carburetors, like the Weber, have the ability to compensate for this by having larger jets which require less vacuum to pull fuel through, so that they can be tuned for similar low-RPM power, but doing this comes at the expense of fuel efficiency; due to the larger jets and barrels the amount of fuel passing through them at a low CFM-rate cannot be measured with as much accuracy. The rule of thumb is: the larger the barrel, the higher the minimum CFM-rate that is necessary for them to run properly and efficiently. Every design is not without its drawbacks, and the drawbacks of the Aisin carburetor are often glaring, but these are the reasons it is designed like this. Now to undo all of that engineering:


Here I have removed the vacuum diaphragm in favor of manually controlling the second butterfly, and the reason for this is a little less technical than the reason the vacuum system was there in the first place. Since this device, now the 'desegregator,' does not operate off of Venturi's principle as a carburetor does, the way in which fuel flow is metered is significantly different. The fuels are mixed 50/50 regardless of airflow speed, and so a sudden opening of the second butterfly at low engine RPM will not cause fuel flow to cease. Normally the diaphragm control of the second butterfly could be left in place, but since I removed the Venturi sleeve from the first barrel the amount of vacuum through the port at any rate of flow will be significantly lower than what the system was designed for, and the result is that the second butterfly will fail to open at the right proportions, or may entirely fail to open at all. In this modification, I have repurposed the arm which pushes the second barrel's butterfly closed when the throttle is released, into one which begins to pivot the butterfly open about when the first barrel's butterfly is halfway open, and through until the first butterfly valve is fully open and the second is fully open alongside it. It is able to do this as I have designed the mechanism to rotate the second butterfly twice as fast as the first. I have taken the mounting bracket which screws onto the diaphragm which the closing arm's spring attaches to, mounted it directly to the desegregator body, and repurposed the spring to hold the second barrel's butterfly valve closed.



I didn't like how the arm became so thin and flimsy when I cut it into the shape I needed, and so I took it and built up more meat on it with weld. I let it cool until it was just below glowing, and then quenched it to give it some hardness. It isn't entirely picturesque here (a grinder and paint makes me the welder I ain't!) but it is strong enough. Here I've put the rotary spring which was on the second butterfly's axis rod onto the arm's axis instead, just to hold it up and keep it from flopping around. It's not really necessary, and the arm could also just be welded in place, but I think the spring is neat. I've also chopped the little tidbit off the bottom of the second butterfly's axis linkage, as it no longer serves a purpose.

 

Due to my region, The majority of wood I'll be using in it will be either mesquite or pine. Pine produces an especially tar-filled gas, but that gas can be cracked into fuel with hot enough temperatures. I'll go into more detail about this when I get to building the gasifier.

Edit: The reactor is rather variable in the types of fuel that it can extract gas from. In fact, it can extract gas from any biomass that isn't a liquid and which does not turn to liquid at core temperatures, nor which are small enough to fall through the grate. It is able to be adjusted to run any type of wood, and is also able to run hemp, husks, sticks, or coal, and can run any other type of biomass of similar dimension. If you were rich enough and needed some entertainment, you could buy a few thousand cigarettes and fill it with that. However, though the device can support a very wide range of fuel sources, many of those fuel sources may be bad for the engine, and so the operator should really only use medium/low-tar wood species, coal, or charcoal. For this purpose, I'm considering pine to be a medium-tar species, as it can get hot enough in the core to crack its own tars; some species can't do that without special provisions. Coal is a pollutive fuel source and should be avoided, however, the coal gas produced from it undoubtedly has the highest energy potential. As for wood; having some basic knowledge about which types of wood do what in a home fireplace will translate directly to what one should put in a gasifier: the less creosote it puts into a chimney, the easier it will be to get clean gas from it. As for charcoal, it's your overall best bet for use in a reactor. Its volume is disproportionately smaller than the lower energy potential in it than wood, i.e., an amount of charcoal that is ½ the volume of an amount of wood will produce ¾ of the gas, or something to that effect. In using charcoal, one can go an overall longer distance with the same volume and weight of fuel, even though it will be burnt a bit faster. One can also use a greater variety of fuels when running charcoal, as the pyrolysis process; making wood into charcoal, takes nearly all of the tar out, and also allows the operator to cook different types of wood in different ways in order to make their characteristics the same so they can all be burnt mixed together instead of separately, as mixing different types of fresh wood means the gasifier will have to be adjusted for a medium between them, resulting in lower gas output than if they had been burnt separately. However, in order to be cost effective the operator would have to first make this charcoal and then burn it in the gasifier, not to mention; the operator would have to learn to get a feel for how long to cook the wood as letting it cook too long makes only ashes, though this also gives great control over the fuel quality. It's a learning curve on its own, requires an extra setup, and is time consuming, and so most people who have run gasifiers in the past have simply used fresh wood, even though charcoal is a better fuel overall and its use has great benefits.

Also, here's the truck I am doing these mods to. Solid axles for the win!

 

These screws got ruined when I was taking them out. Sitting tightly in one place for 40 years will do that. When screws are ruined, just build them back up with weld and temper them a bit, grind them back and cut new slots in them.



Using JB Weld to attach the baffle and the blocking plate I would have liked to have been part of it here. The last thing I'm gonna put up with is these little pieces not lining up when I'm trying to put the desegregator's top on. Having them as two pieces actually worked out here, as if they were both one piece I would not have had access to the one-way valve in order to tune or repair it after I JB Welded the baffle on. I cut the little tab off of the back of the baffle for the same reason.


Check out this time-hardened diaphragm here being useless.



The diaphragm body was part of the carburetor. I just went ahead and ground that guy all the way off.



I had to go and cut new gaskets for it, of course. All the little holes are for the screws, as none of the vacuum or fuel holes are needed any longer, and so they're all blocked off by the gasket. At this point the only purpose of the gasket is to stop dust from getting in and to block the vacuum ports. As you can see here I've also used JB Weld to fill in a lot of fuel/vacuum holes that were part of the carburetor system.



Indian Head shellac is the best thing that was ever made for gaskets. It dissolves with some vodka if you get it on your hands, and it's a guaranteed seal for all paper and cork gaskets. And if you ever need to take something apart that's been sealed with it, it comes apart with little resistance and often stays intact while you remove it instead of sticking to the surface and coming apart in chunks. It's far more reliable than using silicone or just straight paper gaskets, and I would highly recommend it.



Here's the setup all finished inside, and with all gaskets in place. Back in the olden days when you had to cut gaskets yourself, people often left the outside flashing behind. I like how that adds a little old-school charm to this build.

 

Now that most of what goes into the engine has been dealt with, I will now delve into how the gasifier system will work. Below are some diagrams that I've drawn up.



Here's a rough sketch of the system. Imagine the device is like a big cigarette if you will. Sometimes when you light a cigarette the end of it will burn with a flame. The reason for this is that the tobacco inside is being heated to a point where it is releasing flammable gases, and when the flame burns on the end of it, it is the gas being released which is burning. This system works off of this exact principle, albeit with more hardware. In this system I am using, I have done away with the cylindrical body in favor of a more space-efficient square one with a round hearth at the end of the reduction cone, this piece not shown at the end of the cone in this drawing. The shaker grate is suspended by chain and is able to move about with the motion of the vehicle in order to prevent ash from clumping in the hearth and choking out the reactor. From the reactor, this flammable gas mixed with smoke is moved on into a condenser made from a radiator. In this image, which is an older one, the water pumped from the tank is shown entering the system at the top of the radiator, however further research has shown that it should be inlet as close to the hearth as possible, and so in this drawing the water inlet is in the wrong spot. As the water is introduced to the hot gas it is turned to steam, and as the gas/steam mixture is introduced into the condenser, the water condenses back into a liquid and takes any tar droplets with it, which aids in the removal of any tar from the gas and also serves to prevent the tar from being so thick that it clogs the condenser tubules as it cools. The condensate is collected in a container beneath the condenser, and from there the clean gas passes through a filter in order to remove any dust from the gas before it is pumped into the desegregator.



This is a rough diagram of the fuel pump. The fuel pump works off of a small turbine or impeller, much like a vacuum cleaner. A squirrel-cage heater fan could work very well for this purpose, or perhaps a handheld vacuum cleaner. In order to start the engine the reactor has to be fired up and in order to get it working, a vacuum drawing through it must be present. Cranking the engine for minutes on end in order to draw a vacuum through the reactor and through all of the lines not only would take a painstakingly long amount of time, but would be terrible for the starter, and once the engine is running, would add a lot of resistance to the engine's intake, reducing power and efficiency. Thus, an impeller is needed. Due to the nature of the desegregator and how it works, an unregulated impeller would simply flood the engine with fuel and render it unable to start, however, and so a system to govern it must be built. And so a bypass line is put in to connect both the intake and output sides of this fuel pump together, with yet another butterfly valve in the middle. Now I know I said I didn't want any vacuum lines on this build, but controlling the system with manifold vacuum is simply the best way to do it. The principle in operation here; the manifold has the highest vacuum when the throttle is closed, and the lowest when it is opened. Therefore, we can use manifold vacuum to open the butterfly valve when vacuum is highest, which causes the pump to run in a feedback loop, pumping little to no fuel. As vacuum decreases the butterfly valve begins to close, adding resistance to the line which causes an increase in the amount of fuel pumped, proportional to the amount of fuel needed. By limiting how much this valve can be opened, one can set a minimum amount of fuel to be pumped, proportional to how much fuel is necessary to run at idle. Think of this adjustment as your "idle mixture screw." Further on down to the right, and there are two (yet more) butterfly valves, these serving to redirect the fuel when the reactor is being fired up. The bypass valve will be fully closed while the engine is off and the pump is running, which will cause the vacuum needed to get the gasifier/reactor going, and the gas that is pumped through will be redirected here into a burner instead of into the desegregator to prevent flooding. Once the gas is able to be lit in the burner, that is the sign that the system is now operational, and the valve to the burner (labeled "vent to outside" in the image) will be shut as the line cutoff butterfly is opened. Both of these valves are snap-open and snap-shut, each opposite of the other, and there should never be a situation where they are not fully open or closed. Once these steps have been achieved, most of them being automatic, the choke is pulled and the engine is started.



Here's a diagram of the gas pumping system. The air intake line into the gasifier/reactor is shown in this image, and the hearth is present. What is not shown here is the exhaust line, which should run through the gasifier unit in order to aid in heating it, which makes the system more energy efficient, nor is the water inlet line, tank, or pump shown here either. Besides the air intake line, steps should be taken to prevent any leaking of air into the unit, as it will bind with the gas, which reduces the amount of burnable gas produced by a given amount of fuel. Two important things to note, The air intake line, which serves no other purpose but to be a snorkel, can have much of its resistance to flow reduced by making its inner dimensions larger than the regularly-sized air intake line which it connects to. The second thing of note, is the presence of the little box coming off of the bottom of the air line. You might recognize this device as the mysterious black plastic box, which is entirely empty, that the stock air intake piping of the 22R and other engines connect to right behind the grille. This device is called a "Helmholz Resonator." The purpose of this resonator is to reduce resistance to flow in your intake, and the process is as follows: When the intake valves of an engine close, the air which was flowing into them has inertia. As it slams into the valve, it compresses and springs backward through the intake line. As it is doing this, another intake valve is opening and trying to pull air in. The result is an intake stroke which is pulling vacuum against a shockwave which is moving in the opposite direction, which causes the piston to pull against a vacuum, reducing power and efficiency. The purpose of the resonator is to allow this pressure wave a cavity to expand into, which essentially causes it to "change lanes" so that there is an avenue for fresh air to be pulled in without resistance. The size of the box and its location on the air intake piping is determined by engine harmonics and displacement, as this pressure wave is essentially a sound wave. Because of this nature, the resonator also serves to make the intake quieter.

 

I'd like to show you this device and how it works:



This is one of the original diaphragms off of the 20R. The line coming off of the side of it is the main control line, and varying amounts of vacuum on it will cause the push-pull motion in the stem. The second chamber uses vacuum to control the first, and has an adjustment screw on the end of it. By turning the screw, one can adjust how much the stem moves with a certain amount of vacuum. This screw is set at the Toyota factory and is held in place with orange paint to keep it from turning. I will be using this device to control the bypass valve on the fuel pump.

Update: A rough sketch of the bypass valve system:



Edit: this diagram has been updated to include the spring tensioner that I found was necessary during R&D which I documented in a later post. The update is marked with a star.

The length of pull with any given amount of vacuum is adjustable via the screw on the diaphragm cluster. Once this adjustment has been made, no other adjustment of it will be needed and so I will affix the screw in place with Loctite.

 

Why are your pictures black and white?

 

I like the way that it looks

 

I think this is interesting and I really hope you get it all to work but I'm going to play devil's advocate for a minute.
I don't really see how you'll be able to harvest enough gas, to have enough on demand, to allow you to apply throttle and drive your truck anywhere above 1,000 rpm.
In section 5.1.7 of that food and agriculture paper it says they leave that generator running at 1,500 rpm. The very end of section 2.1.2 says engines using producer gas should not be operated above 2,500 rpm which is really when a 20R begins to come to life.
In section 5.2 it says the start up procedure is around 20 minutes!

How much gas can you expect to condense to be able to power a thirsty 4 cylinder engine? Do you have to keep the gasifier fed and "burning" constantly?
Is it burning? I'm kind of confused on this part. The gasifier's job is really to heat material right to the point that it releases this precious gas but not actually ignite or burn it? Then condense the gas. Then mix that gas with a bit of air and feed that into the 4 cylinder for internal combustion as per usual?

Again, I'm all for this because it's different and interesting. I am skeptical of it's practicality for a car though.

 

The 2,500 RPM limit is a problem that I'm going to have to work with. The purpose of the heavier flywheel and stroker crank is for this, as this mod will allow the engine to turn slower and make usable power at a lower RPM. I cannot say with certainty the exact numbers for this, as no data exists for this specific engine and system, and I will have to do calculations for this specific design once I get it operational, and any predicted behavior up until that point will just be an educated guess. At that point, it is very likely I will have to play around with re-gearing and perhaps some other modifications to make the truck work optimally, but for the time being I cannot even begin to guess what kinds of gear ratios and whatnot I would have to put into it until I have it operational and hooked up to a dynamometer. For a significantly faster RPM ability I would have to bore the cylinders out probably another half an inch or so and reduce the stroke, but that is not possible on these engines so the next best modification I can do is to bore them out slightly and add stroke for more displacement, and add a heavier flywheel so that the engine can run at a lower speed, so that the longer stroke can be useful for something. Because the pistons will move faster at any given RPM when the distance between the crank pins and main bearings is increased, having a stroker crank in the engine will reduce its maximum RPM, as laminar flame speed does not directly determine how fast the engine can turn, but how fast a piston can be thrusted down the bore. An increase in displacement is necessary to generate equivalent-to-gasoline power, and optimally the stroke should stay the same or even be reduced with a dramatic increase in bore size in order to not sacrifice higher RPM operation. However, the only way I can increase displacement is with a stroker crank, and so the only option I am left with is to add a heavier flywheel, to increase inertia in order to decrease the minimum speed required for the engine to operate, which will enable the engine to begin to create useful torque somewhere around standard idle speed instead of above 1,000 RPM. Because of this system the truck will never be particularly fast, will have a long wind-up time, slower acceleration and therefore reduced horsepower, but will also have a higher top speed due to a considerable increase in leverage. If I can achieve a top speed of 40 mph, I will be content enough with it. Any way that you build it, however, an engine that runs off of a producer gas setup will produce less overall power than it would if it were running on gasoline.

Here's a video of a truck that has been modified like this, proving that it can be done. If I remember correctly; a land speed record was set at 74 mph in the salt flats of Utah. I don't expect to be able to reach any speeds like that, but it proves that decent speeds are possible. However, all of these vehicles have been created with no modifications to the engine other than spark timing, so all of these engine mods I'm doing are things that I've had to invent with no data. You could say I'm pioneering this.

The truck in the video is called a Chevy LUV. The LUV had an 80HP engine with an 84mm bore and 82mm stroke. This 22R, with its over-bore and stroke of 94mm, will be able to create significantly more power at any given RPM, however the LUV's engine in this video is capable of rotating faster. The reason is simple; a shorter stroke translates to a piston that doesn't move as fast at a given RPM, and so a gas with a lower laminar flame speed can be used. The piston will travel 82mm of distance on every stroke, and there are two revolutions per 4 stroke cycle, there is 164mm traveled every revolution, per piston. That works out to 246,000mm traveled per minute at 1,500RPM. Being a 4-stroke, the combustion strokes make up ¼ of this distance; 61,500mm per minute. My engine's pistons, having a 94mm stroke, travel 282,000mm per minute at 1,500RPM, working out to 70,500mm combustion distance per minute. The Food and Agriculture Organization did not work out the laminar flame speed of the gas at a given compression ratio, and a higher compression ratio will always result in a faster laminar flame speed, whatever the laminar flame speed is at a given compression ratio will influence max RPM of the engine. This is an example of important data on the subject which simply does not exist, and I'm going to have to simply find out on my own. Nobody who has done a gasifier conversion, that I know of, has ever had the wherewithal to post their max RPM with their specific engine, and so I cannot calculate this number until I have mine up and running. As far as I can tell, the tone of the truck's engine in the video tells me that the engine can spin at a 'pretty ok speed.'

The start-up time for wood gasifiers is rather long, and 20 minutes is not a bad approximation. I would like to build an auto-igniter, powered by propane or something, to greatly reduce the amount of time it takes to start the thing. However, I'm not going to invest in a system like that until I get the truck actually working.

As for the gas system, yes the gasifier must be on and 'burning' constantly. Combustion is a chain reaction, when an object like wood is heated, it releases gases which bind with oxygen, producing heat. As these gases become hot, they glow which is what you see as a flame. The heat from this fire causes the wood to release even more gas, which makes more flame. What you're doing in a gasifier is giving it just enough air to sustain that reaction, but when that reaction causes even more gas to be released, there is not enough air left over for that gas to burn. Simply put, imagine if the heat produced by the burning of one cubic foot of gas was enough to cause the wood to release ten cubic feet of gas. Since you are only putting enough oxygen in to burn one cubic foot of gas, one cubic foot of gas burns, releasing ten more cubic feet of gas, as nine cubic feet of gas remains for you to use in your engine. In this process, you are sacrificing a small amount of gas to fuel the reaction, and the leftover gas produced can be piped to an engine.

As for condensation, 'the gas' itself is not condensed. Because of how this system works, not only does it produce CO, H2, and CH4, all three of which are the gases you want to keep, but it also produces some water vapor and a fine mist of wood tar which coats surfaces in lacquer and gets intake valves stuck open and whatnot. Because the tars that come out of the gasifier turn back to liquid at a low temperature, this whole mixture is piped through the condenser, so that the tars and the water condense into a liquid and flow into a collection tank. The burnable gases that you want to keep do not condense, and are piped to the engine as a gas. The tar is very viscous, however, and will clog up the little tubes in the condenser. But think about adding water to syrup, which is a wood tar. By adding water to syrup you can make it a lot more runny, which is the purpose of adding steam to the system; so the condensed tar will not clog the piping.

As for not having enough gas, the solution is to make the diameter of the hearth larger or smaller. A similar principle applies here which applies to carburetor barrels: A small engine with too big of a hearth in the gasifier will not be able to draw enough air through the hearth fast enough for it to fully heat up and run the chain reaction optimally, and an engine with a hearth diameter that's too small will not be able to draw enough gas because the flow is restricted. A "Goldilocks Zone," if you will, is needed here.

After I dyno the engine, I'm going to have to have the charts of power and torque curves. In the highest gear (that it's capable of pulling, which will be 4th at least) I'll get it going until the motor reaches max RPM, which will be determined by max flame speed of the gas. Looking at the dyno data, I can determine if any horsepower is not being used, i.e., if I figure out what amount of energy is being used to propel the vehicle at an RPM half the maximum, I can use that dyno data to find out how much torque is being used at the max RPM. If that amount of torque is calculated to be lower than the amount which the engine is capable of producing at that RPM, then it means I can modify the gear ratio for either a higher overdrive, or less reduction (depending on if it can pull 5th, or if the most it can pull is 4th). This will mean that at that RPM the engine will have to work harder to propel the vehicle at a faster speed, thus using the torque and HP that were otherwise wasted. A simple calculation: If the truck is in 4th gear going 45mph, the engine is turning at a max 2500RPM, and the calculations from the dyno charts show that the engine is producing 80% of its capable power output at this speed, the gear ratio should be adjusted so that 20% more power is required for the engine to maintain 2500RPM. The end result of this is a 20% increase in top vehicle speed of 54mph instead of 45.

 

Well that is pretty cool! Thanks for updating and I can't wait to see it run.

 

Huh so I was thinking the gasifier would be a large stationary plant, the gas would be collected in tanks like propane then used to power the vehicle. But it sounds like the idea is that the gasifier travels along with the rig, is that right?