"Inventing" a "New Multi-Fuel Engine"

utterpirate

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The block and the bottom end would never stand up to the stress and pressure of compression ignited fuel. If the engine were to be torn down and rebuilt frequently it might work for a while. Peak pressures are far higher with compression ignition (all fuel burned at once) then with the controlled flame front of gasoline spark ignition. The block would need to stiffer (maybe compacted graphite iron) and the bottom end bearing surface would need to be increased. Multi pulse direct injection could alleviate some of the peak stress but a better starting point might be the new Ford-Jag-Range Rover Lion series engine.
 

dmetalmiki

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Thats a LOT of reading..But I can shorten it somewhat by saying ANY compression Ignigition engine WILL run on a variety of "fuels". If you jack up the compression ANYTHING (reasnable) will ignite and propel.
IE. My old direct injection ROVER MONTEGO will happily run on the SAME "stuff" as my multifuel trucks without doing a thing!
so ANY improvement or adjustent to those (sort of) engines will let you run..........Cheap (er) juss' my 1/2 pennizworth..
 

73m819

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You guys are talking about converting a SB 350, why not start with a 350 diesel for the design then work from there, OLDS had one in the early 80s, think Chevy had the same motor in a pu, just changed the valve covers
 

Wolfen

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You guys are talking about converting a SB 350, why not start with a 350 diesel for the design then work from there, OLDS had one in the early 80s, think Chevy had the same motor in a pu, just changed the valve covers
I Remember those Emgones, they were a POS.
 

73m819

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I Remember those Emgones, they were a POS.
yes pos though ran great if taken care of, what I was saying is start WITH that design, It gives you someplace to start, fix the faults then go from there
 

rtbcoop

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Sorry for waking a dead thread but I found it very interesting and had a few questions. Would you be able to run straight WMO through normal (maybe enlarged) diesel spray injectors if you used a fuel preheater or something like the flame heater that the deuce multifuels have? This would decrease the viscosity and make it more like diesel. It would be nice to have a multifuel with more power than the LDT-465. Is the high compression ratio what makes the LDT-465 so gutless in comparison to other diesels? If that is the case, the entire purpose of this mod/build would be moot since WMO requires that high compression ratio to burn correctly.
 

my new hobby

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I read somewhere (dont remember where) that the reason it is a low power to weight engine is because to fuel is NOT burned all at once.As I remember it that 5% that is the spark starts to burn the fummes coming off the puddle in the piston, since the liquid fuel don't burn. Because of this the burn time is longer (accually burning on the way down). That was part of the reason the engine only weighed 3500 lbs and not 10,000. So for me the question isnt will it handle the power but how to get the fuel in, what engine to start with, how to time it and what kind of actual power would it produce?
I have thought about getting a blow MF off of someone here and seeing if it couldnt be cut down to 3 or 4 cylinders and the pump retimed. But my goal isnt to power a smaller car(I like big trucks) but to run a stationary 20 or 30 kw genset to get of the grid. If that could be done, then I dont see why we could'nt cut a good one in half and two or three good small engines running on "junk" fuel.
I am thinking about just getting a hole MF and making a protable(trailer) power station with multiple 10 kw heads, a hydrolic pump for bilt on log splitter and an air compresser. So I could power a small community or a hole house and all my big tools. Just my way of thinking.
 

rtbcoop

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So if the compression ratio does not affect the power, I'd say take a stock diesel, (LB7, 6BT etc.) raise the compression to 20:1 (new heads or pistons), add a flame heater before the IP, add a turbo with a wastegate and maybe increase the size of the injectors so that they wouldn't get clogged so easily. Sounds like a 350 hp, 450 ft/lb multifuel motor to me!
 

Special T

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I just finished reading to the end (Page #2, Post #18) of the thread "Completely Random" where the OP was asking about why/how a multi fuel worked. (For reference, here is a link: http://www.steelsoldiers.com/alternative-fuels/68037-completely-random.html )



Along those lines we want this engine to remain as "Stock" as possible so that we can get parts for it. This means that we want to use a donor engine that is more or less readily available, not something that is rare or super expensive.

In the process of building this power plant we want to use as many off the shelf parts as possible, and the more common they are the better. Remember, one of the key goals is to be able to maintain the engine for a long time in the future and keep in mind that normal supply chains my be interrupted/intermittent or even no longer operating at all so the more common and easy to find the parts the better.

The first question in the quest to do this would be do we use a gas or diesel engine as the starting point, and WHY? I am guessing diesel. If that is the case, Then I would ask about the feasibility of using the "Pre-computer" Cummins 5.9 or possibly the 4.? (I can't remember what the 4 cylinder size is). There are plenty of 5.9's around, parts are pretty easily accessible and they seem to be pretty solid, durable and should be able to withstand a fair amount of abuse. (I know the 4 cylinder is smaller and lighter, but are the parts as readily available? Would it make a better choice for our project?)

So, assuming that you do want to start with a diesel and that the 5.9 would be a good diesel choice, what must be done to it to get it to successfully, reliably and non-destructively, (It has to last) provide motive power to a 4x4 or 6x6 wheeled vehicle while using all or most of the same alternative fuels that a multi-fuel Deuce will burn??

Keeping inmind the OP I think the 5.9 and its smaller brother are the way to start off. External parts on the Cummins motors are interchangeable (mostly) and have been used in everything from PU trucks, heavy equiptment to Gen sets. There are currely people using these motors to repower jeeps and half ton trucks. Parts are everywhere and they are bullet proof.

IMO this "emergency fuel need" means that you need to use readily available fuel, and likely the more refining it needs the harder it is to come by. To me that means filtered oil in some way.

My neighbor is a Heavy diesel Mechanic for Powerplants, cruize ships and the like. They nearly all run on Bunkerfuel which is what most of us would consider Asphault. They heat the asphault to 300 degrees or so so that they can pump the stuff to flow through the system, and its CHEEP!

So what does this mean? If it were ME i would focus on the fuel delivery system NOT the motor itself. I would investigate what makes the seals in the injection system fail in terms of heat and solvents used. Likely My rig would have a 2 tank system so that I could start it on a fuel that has a better viscosity and BTU rating until it warms up. Heat the "inferior fuel(s) so that they will work. This preheating is not necessary in some hotter environments (Where it is hot as ****) but designing the system to be "optimum" in many differnt conditions. Having a truck that works great in E WA half of the year when its 90 Deg outside is not as benificial as one that could be used year round.


There are LOTS of cool tricks from cutting your WMO with Gas to putting a 110 volt block style heater in your tank to make these things work. To ME that would be the impressive part of putting together a package that could run nearly anywhere.


I think the hard part is the WILL to do this kind of project. All the Technology is here TODAY. Most of the barriors are Legal and Political, and Im not that interested in getting one of the fines that some have recived.
 

rchalmers3

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After all the discussion, and all the excellent ideas, I repeat what I proposed in my first post: perhaps the best solution to keeping the multi fuel alive and affordable is to have access or license to the tooling and manufacturing of the design.

Yes, there is some satisfaction in reinventing the wheel. I have done that a few times, but in hindsight there was always a simpler and cheaper alternative that was there to irritate during the project or surprise me, after my efforts were done. I'm not gonna hold my breath, but 3D metal printing might (in a decade or so?) play a role in extending the life of our hobby. Small production runs of a set of pistons for a one engine at a time may be feasible. Whomever holds the code for the printing will have an advantage.

Rick
 

Wolfen

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Speaking of 3D Printing I remember watching a Episode of Jay Leno's Garage where he was having a Part made for one of his Antique Cars using 3D Printing.
 

red

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Diesel engines will use WMO/WVO once the fuel is warmed up to make it flow easier through the fuel system. It's not so much the engine that needs to be looked at for a multifuel design, it's the fuel system (with the exception of running gasoline in the mix). The other concern would be the computer sensors on modern diesels. I know the 6.5L diesel engine runs fine on WVO when it warmed up, but the 'optical sensor' that the electronic controlled injection pump uses throws a fit. No personal experience with the newer diesels and running alternative fuels.
 

Hammer

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Some of the bigger problems with the 'normal' diesel designs are related to atomization of the fuel to burn it efficiently.
Our multifuel engine actually bypasses almost all of these issues by using low pressure injection (injectors squirt streams of fuel, not spray a mist of fuel). So the injectors don't coke up, there isn't all the were on the fuel delivery system.

It simply relies on the piston cup design and the incoming air flow to atomize the fuel and burn it during the compression stroke. This is how it doesn't pre-ignite gas in a diesel engine, and still allow gear oil to burn!
You want to improve or create a new multifuel, stop thinking of the stop gaps of modified injectors (GM 6.2L work much better with different injectors, higher pop pressure and unshrouding the tip.) And start thinking about modifying the piston/piston cup, and how the air is injected into the cylinder.
Simple put, you squirt the fuel into the piston cup. Only something like 3% of the fuel is actually atomized during the injection event!

After that the magic happens.
Concentrate on how the air enters the cylinder, and how it interacts with the fuel in the piston cup. That is how the fuel is atomized.
So, create a better 'swirl' of incoming air.
Make sure it concentrates air towards the piston cup throughout the upward travel of the piston.
Tweak the piston cup to allow for better atomization of the fuels (link posted earlier with holes in the piston that push air into the piston cup, etc.)

Compound turbos to keep a better level of boost throughout the rpm range. This isn't so much as to create massive power, but to properly burn the fuel being used. This 'should' really keep the EGT's lower, which is an issue with these motors.

These are the lines to think on to improve or invent a new version.
I would think that if you can recreate the system used with the multifuel in a newer motor (baring patents, legal issues, etc.) this would be the ideal starting point.
First you need to find a setup that closely resembles the air intake into the cylinder to make sure you have your air movement into the cylinder matching a profile of the multifuel design.
After that, make new pistons that resemble the piston cup present in the multi fuel.
Then completely 'dumb down' the injection system to run much lower pressures, and have custom injectors made (actually the easiest part of this whole thing.)

I would love to see two versions.
One a small 4 cylinder that could power smaller cars or generators (which I think is the BEST use of a multifuel BTW.)
And a larger 6 cylinder that could power pickups and other more common sized applications.
 

Domodude17

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Re-Hash: Building a new multifuel engine

I have done a lot of reading of this thread and I thought I would chime in with my ideas and see what the members here think. Full disclaimer: I am not a diesel mechanic, have never worked on a diesel, and don't own a deuce (YET!) and iv only done a little bit of work on small gasoline engines so if something is wrong feel free to knock me down a peg. http://www.steelsoldiers.com/showth...enting-quot-a-quot-New-Multi-Fuel-Engine-quot

Everyone has suggested the Cummins 5.9 as a good donor engine. Looking around, it has a compression ratio of 16.3:1. Since one of the earlier posts here stated that boost pressure and compression ratio are related, I checked using a boost/compression calculator.

https://www.rbracing-rsr.com/compression.htm

About 5 psi of boost, assuming 1000 feet altitude would put us right around the 22:1 compression ratio. Perhaps that could be accomplished without modifying the size of the piston or head or anything by simply adding a small supercharger to the engine itself, perhaps with a wastegate or something that keeps the amount of boost it adds low.

So then the turbo comes into play. If we were lucky maybe we could get away with keeping a standard turbo on it. Looking back at the 5.9, I saw on a different forum that guys were about to get over 40 psi boost sometimes, so we'll assume an average of 30 psi. Using the above calculator again, this puts the "Compression ratio" that the engine sees at nearly 50. Working backwards, and assuming the ~22:1 compression ratio in the 5.9 with the supercharger adding the extra 5 psi, you can see we can get ~20 psi of boost until we reach the compression ratio of the stock 5.9 at 30 psi boost.

I guess now the question is whether or not the supercharger is gonna be able to put out 5psi of boost from just cranking to get the extra air into the cylinder, and if thats even a viable solution to our compression ratio issue. If the supercharger had an adjustable waste gate then you could probably "tune" the engine to different simulated compression ratios. If the supercharger is efficient enough, we might not even need a turbo on the 5.9, although it could possibly help fuel economy.

Wow, so this probably ended up being more complicated than I thought. Iv been lurking here for a while but never bothered to make an account until now. So to hopefully alleviate any confusion, the general order is: supercharger to get the 16.3 compression ratio to a simulated 22:1, using about 5psi boost. Use a turbo to get the extra boost that the engine would need, but cap the boost at a safe level that the 5.9 is known to be able to handle. This is all assuming we are able to machine the appropriately shaped pistons and make the custom injectors.

Also first post :smile:
 

patracy

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I have merged your thread. You're missing a lot of things. Static CR is the key thing. You can't run the engine under boost at idle all the time. Second, the swirl design in the piston bowls are missing, along with the improper injector nozzle, angle, and pattern.

A p-pump'ed 12v Cummins will however happily ingest WVO and WMO (clean of course) with minimal changes.
 

Domodude17

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So it looks like we would most likely need to increase the piston height to alter the compression ratio. I do know that we would need to shape the cup in the piston and modify the injectors to inject a stream, I am just looking at it piece by piece. I don't know the ideal design for the piston cup shape and swirl design and everything, but I hope with some kind of CAD/FEA software I could find the shape most efficient at atomizing the fuel.

As a noob, why can't you run the engine under a little bit of boost all the time? Will it just destroy things?
 
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