Running a Diesel on Hydroxy gas

[Brad4321]

I am not saying that hydroxy does nothing for diesels, I am just not has confident about the flame front theory behind it. However, I did have a conflicting idea earlier today. Diesels do have one minor flaw in their injection. By injecting the fuel at the same time it ignites, there isn't any natural dispersion of the fuel in the chamber before combustion. In theory, you could have an oxygen depletion at the injection point and a surplus around the sides. Nearly all diesels (and gas engine alike) have some sort of swirl design to get the gasses moving within the cylinder, but many of the older diesels do not do this. The hydrogen could cause a more even burn and use of all of the available oxygen. This could explain the less dense black smoke reported under hydrogen (a more complete burn of available fuel, this less fuel would be needed). The other thing to keep in mind is hydroxy is a fuel and although it takes quite a bit to make a difference in a large diesel engine, every little bit helps. This could also explain the smaller overall gains experiences with diesels over gas. It seems to me that there are many more gains to be had as far as flame fronts go on gas vs. diesel. It would be interesting to see some results on a direct injection gas as although there is a delay between the fuel injection and spark (to my knowledge, not really researched this), the results would be close to that of a DI diesel.

The old FE engines, as much as I love them, are horribly inefficient. You could put that engine on a go-kart and be lucky to hit 15mpg. That said, they are a true powerhouse in their upper models (427 and 428) especially with new aftermarket cylinder heads. I have a 352 big block for my drag car (a destroked 390).

Horsepower sells cars, torque wins races. Torque moves things and is a measurable quantity. Horsepower is a calculated figure. Horsepower is a good measurement on how fast something will get done, specifically acceleration, but torque is where it is at. A 350 cubic inch diesel (and gas as well) is very small for a 1 ton truck loaded to capacity (and well beyond as we all do). The engine would have to work very hard to pull the truck at its GVCWR, which is the key to its success. There has been an argument over time on which gets better FE...less throttle at a higher rpm, or more throttle at a lower rpm. With our overdrive transmissions, it is obvious which one has won.

Once I get a good grasp of generator design and have large, solid generator I will install it on my diesel truck as it still is a daily driver. I am wanting to experiment on my ranger in case I make a big mistake...

There is one more thing to consider if anyone is wanting to put a hydroxy system on a diesel. Diesels ignite due to the heat of compression. If you hook up a compression gauge to a freshly broke in gasoline engine, you will get approximately 200 psi. In a comparable diesel, you will get about 800 psi. Gas engines typically run from 8:1 to 10:1 compression, where diesels operate from 15:1 to 23:1 compression ratios. The temperature of the air in the cylinder at the point of injection is approximately 1000 degrees. My point behind this is, although I do not know the flash point of hydroxy, I am nearly certain is it much lower than this. It is quite possible, in fact I would almost guarantee that the hydrogen would ignite before the engine actually fired (giving it a "knock" or predetonation). Even as stout as diesels are built, this would be very bad for the engine. Of course, this would only occur with a significant amount of hydroxy and I am guessing wouldn't be very noticeable or even exist under 2lpm/cui (since diesels do not limit available air). Similar things happen when running a diesel on propane. It is my current half-drunken theory that this problem would prevent a diesel from being ran on 100% hydroxy unless internal modifications are made (such as finding out the flash point and reducing the compression ratio down enough to that the hydroxy would ignite at near the correct point in the cycle). Of course, since nearly all diesels today are turbocharged, when you put compressed air into the cylinder, it effectively raises the dynamic compression ratio creating more heat on compression. This is why turbocharged diesels typically run from 15:1 (cummins) to 17.5:1 (international), while N/A diesels run 20:1-23:1. The turbo's boost makes up the 5psi static compression loss.

I am not one to post much, I just thought I would say a few things in this thread since it is my thing, but I will be around for a while. I have a CRX HF (it is a two seater designed for High Fuel economy, hence the HF, very small car) that I am wanting to get very good FE out of do to my long distance driving (mainly do to visiting family). The car gets 55mpg stock, and along with aerodynamic mods, I would love to get near 100mpg. The car has a ways to go before being a driver (currently has no drivetrain and is getting painted).

[Bob]

Brad:
  You mentioned that a diesel injects the fuel at the exact time it is ignited... and to my knowledge this is false... but then again I am not up on Newer models or their design...
yes they have High injection pressure from the pump but that is not because it injects it on the compression stroke, typically to my understanding it is at the same time that the valve opens on a 4 stroke diesel that the injectors inject the fuel into the cylinder. on a 2 stroke diesel it is no doubt different I have always assumed that the injection of the fuel was done at the time the Intake ports were opened, to allow a good mix of the fuel/air before compression , even though its only a few milliseconds before the compression stroke happens,  mixing that fuel with the air is very important.
if the fuel is indeed injected on the compression stroke on some models (which wouldn't surprise me!)
then they have to be a rather inefficient running engine... but I am sure, if they make them that way they worked most of the problems out of them....
 I wouldn't buy a diesel that injects the fuel at the same time it is ignited . to me it just sounds counter productive.
 My work on Diesels has been limited to older ones, mostly 4 stroke diesels, although I have worked on 2 cycle diesels in Kabota tractors and they were really a nice reliable engine.( I think those were 2 stroke, not positive)
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at any rate... the flash point for Hydroxy gas is about the same as gasoline/air... I remember looking it up but I can't remember where I did... but as you say, gasoline and Diesel are 2 different things
the flash point for diesel as compared to gasoline is much higher... so your probably right there in assuming a Knock/ping possibility .... if I were you and had a diesel I would find out what the flash point for "Browns gas" REALLY is and stop guessing.  However on the older diesels You could change the timing of the pump to make up for the easier to ignite fuel... I don't know about your trucks.
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you made me think about Diesels and pouring in more fuel for more power as compared to how it works in a gas rig... and for that I thank you... I never looked at it like that but your explanation holds true.. the subtle differences between the 2 engines has always intrigued me, but Just like the gasoline engine the Diesels of Old metered the amount of air coming in as well as the amount of fuel they injected. so Just like the gasoline rig the diesels of Old added more air and More fuel upon acceleration.....
 this Must be so or you could not keep the proper ratio of fuel to air in the cylinder...
if the air intake was Unrestricted, in the diesel engine the engine would be running very very lean at idle and Rich at full throttle.... which I know a diesel COULD DO... but its not very efficient to do it that way... its far better to give the engine a certain ratio of fuel to air in each throttle setting, no matter where its position is, you save fuel and the temperature is more or less constant. and the engine won't miss a beat.... it will run fine at idle instead of surging or struggling because of too lean of a fuel to air ratio.
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A diesel Like a gasoline engine runs on small Puffs of the correct fuel to air ratio.... most of the time the engine is in a state of high vacuum because of that.... in other words  at 2000rpm  your giving each cylinder 1 cup of fuel/air mix.... but the cylinder's volume is a full quart !....so the explosions in the cylinders are small booms not big ones <GRIN>
this is the principal of either engine, you do not have to fill the volume of the cylinders as your driving down the road.... actually the only time they are anywhere near full is at full throttle or when under a turbo charger. Understanding this is paramount to saving fuel .
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f.w.i.w.
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Bob........

[Brad4321]

All diesels that I am aware of inject the fuel as it is ignited. The reason is simply because it has to. The autoignition temperature of diesel is 410 degrees. If you were to premix the diesel with the air and then compressed it, you would have no control over the ignition point. The diesel would simply ignite when this temperature was reached. They fuel ignites as it comes out of the injector so they can have precise control over the ignition timing. If they did not, they would have no control over it since it is temperature related. This is no different than igniting it with a spark plug as far as timing goes. In fact, new diesels have "multi shot" injectors, which means that the injector fires multiple times per power stroke instead of all at once. This is to reduce engine noise.

Diesels engine smoothness is not related to air/fuel mixture at all like a gas engine. Running super lean at idle does not make it run rough or effect the engine in any way. It does make the engine run really cool and idle which is one of the reasons it is really hard to warm up a diesel by letting it idle. Running super lean does effect the emissions as there is a stoichiometry for a diesel as well for emissions, hence the reasoning for the newer engines having throttle valves. Diesels tend to knock and run "rough" compared to a gas engine because for all purposes, they are "knocking" or predetonating every time they fire. By making the injector fire multiple times, you get 5-7 "small" knocks instead of one big one quieting the engine down. This is why diesels are all forged internals, sometimes even forged steel for pistons, which drastically decreases their max safe RPM. This is also why diesels tend to cost more to buy than gas engines. Each diesel is built using similar parts to a gas race engine, which also drastically helps extend their lifespan.

Your description of vacuum is correct for a gas engine. A diesel never has any real vacuum, maybe a couple inches of just intake/head restriction until the turbo kicks in, but that is it. A gas engine must run near stoichiometry all of the time, it just restricts the amount of air at lower throttle so it can inject less fuel. A diesel just injects the fuel it needs for the given power. Both work just fine, and most likely the diesel method is slightly more efficient. At anything less than full, black smoke throttle, there is a better chance of getting a complete burn on a diesel than a gas with an inefficient combustion chamber design. Diesel engines are more fuel efficient than gas engines for two basic reasons: higher compression ratios and slightly more BTU's per gallon of fuel (147,000 BTU) vs (125,000 BTU). You can increase fuel economy (which comes down to engine efficiency) drastically by raising the compression ratio and running (some) aftermarket heads. Like someone said before, most things that increase power will also increase economy.

As a side note, I found that the gas autoignition temperature is 475 degrees, or actually more than that of diesel. However, the flash point of gas is -40 compared to 143 for diesel. This is why you can literally throw a match in a bucket of diesel and it will go out. On one cold morning, I took a small propane torch to a cup of diesel and melted the cup before the diesel would ignite. Diesel injection pressures are so high to properly atomize the fuel as it is injected into the cylinder. They atomize the fuel much finer than gas injectors do.

[Bob]

Huh ! Very interesting ! All these years My ASSUMPTION of how the Diesel works has been Wrong !
thank you for the correction !
 I know you speak the truth because you explained the REASON so well...  THANK YOU!
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 See guys ! Ya  learn something new every day weather ya want to or not! LOL !
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 Just that one point the "igniting of the fuel at the time of the injection", Changes for me how the engine actually works, simply because if you change that one point MANY things have to follow, as Brad has so graciously explained.
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I thought the reason Diesel engines we so Noisy was because  they were compressing the fuel/air MIX
and it ignited due to compression , this induced ignition happens somewhat uncontrolled, hence the knocks, but the heavy makeup of the engine pulls it through anyway. BUT if that were true when the engine was HOT the timing would come earlier and earlier till the engine would start running backwards. So it has to be Igniting the fuel at the time of injection, giving you CONTROL of the timing at which the cylinders fire off...
it also gives a very good reason for the extremely high injection pump pressures... it has to over come the pressure of COMPRESSION in order to inject the fuel.(not to mention at such high pressure the Diesel would be atomized completely I'd think!) the injection pressure would have to be higher than the compression pressure in order to facilitate atomization, it would instantaneously vaporize in the squeeze of compression with all the air of the cylinder,sense the injection pressure is higher than the compression/ignition pressure... it would be very broken up, probably down to the molecule level.
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Now I gott'a go look at the O'l mercadies Diesel engine I have out there setting under a tarp and see if there is a butterfly on the intake....
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BOY that makes my head spin LOL....trying to correlate all I know about Diesel's with this new information heheheheh.
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Thank you Brad you are a good teacher. and THANK YOU for sticking with it until I understood, as many people wouldn't have, they would just have left me to my ignorance....
 and that's not a nice thing to do in my book ! <GRIN>
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 hehe Man that's Neet it makes sense now...
 live and learn !
Thank you Brad !
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Bob.....
 

[Brad4321]

Want to get really confused? If your mercedes is older (80's era, possibly into the 90's), I am pretty sure they are indirect injected. Here is the best picture to demonstrate:

http://www.sweethaven02.com/Automotive01/fig0503.gif

The injector sits in a smaller chamber connected to the main combustion chamber. Combustion starts in the pre-combustion chamber then works its way into the main chamber to push the piston down.

IDI (indirect diesel injection) engines are long gone for the most part. They are an old, fairly complicated in comparison, technology used to reduce engine noise and stress on the internals, but they lack the efficiency of the newer direct injection diesels. Heavy duty (semi and above) engines have been direct injection for decades (I want to say 1940's, but that is a guess), but pickups and cars just started to get direct injection about 15 years ago.

Wikipedia has a good article explaining it all if you are interested in the details.

It occurred to me last night that I have seen a diesel ran on pure hydrogen (not hydroxy). I do not know the specifics on it, but I do know they replaced the diesel injector with an actual spark plug, and still used a turbo to inject air. I never heard of any issues with hydrogen interacting with the metal, but that doesn't mean it didn't happen...or they didn't use some type of special material/coating. I suppose the only real info I can offer on this is that it was ignited by a spark plug.

[Bob]

hehehe Yah ... but remember Pure Hydrogen doesn't react the same as Hydroxy gas (browns gas)
pure Hydrogen is harder to ignite has a much slower flame front and is in general 
"neutered" Hydroxy gas...hehehe its amazing how much of a difference little oxygen makes !
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I know of about 4 people that have injected Hydroxy gas into the air intake on their diesel trucks
one said there was no difference at all as far as the gas mileage goes the other 3 calmed a substantial increase in MPG  although the increase isn't stellar like in some car applications
there was definitely an increase by a few miles per gallon .
 I agree with your assessment Brad, that the increase must be from the Hydroxy gasses ability to Help burn up the un-ignited fuel... the most increase I've seen in a diesel is about 4MPG, where I have seen over 10mpg increase in gasoline engines.
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I think partially because of the Size of the engines being dealt with and the amount of Hydroxy gas being used per Cubic inch displacement...
 its almost inevitable that if its a gas engine its smaller than the V8 (unless its a mercadies or VW! LOL) because the trucks with the diesel engines in them are usually Very big. 5 to 7 liter at least, where my pickup has a 2 liter engine in it (R22 toyota 2.4liter)
I have yet to try a hydroxy unit on a big v8 or large displacement engine.... but I do know that about 1LPM to 2LPM per liter of engine displacement works purdy darn good in either gas or diesel engines...
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SO what kind of cell are you making Brad ?
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Bob........

 

[Bob]

Ok Brad... explain this... this is a pic of the Mercadies engine...its a 4 stroke diesel that has seen better days but still runs good, its the transmition that pops out of gear that is the major problem with it....
you'll notice at the top of the tall picture the air butterfly, it is precisely controlled by the pumps throttle position, so that makes it metering in a tiny amount of air at Idle so it has the proper fuel to air ratio in the fuel/air mix 
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However, if they are firing the fuel air mix at the same time it is being injected near TDC somewhere
(if my timing of the engine and memory is correct) in this silly engine it is Running most of the time in a vacuum , just like a gas rig.... right ?... sense the air IS restricted each cylinder gets the proper amount of fuel/air mix and can run on small explosions just as a gas rig does...(obviously)
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you said that a diesel's air intake is not restricted like a gas rig is , but this one obviously is
do you mean Some diesels operate with no air control ? if so which ones, because I don't ever remember seeing a diesel engine without an air butterfly of some sort.
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Bob.....

[Manta]

Just had a look at an engine manual for the 1.7 ltr Opel Diesel. Fuel injection is quoted as commencing at 3 to 5 degrees BTDC at idle.

Manta

[Brad4321]

I usually only work on heavy duty engines (11L and above), but I do play around with midrange (5L-10L) on the rare occasion. The smaller car stuff is completely out of my experience. I really don't know what they are trying to accomplish there, but once I get a sec I will research it as I am curious. Outside of the new 2010 models, I have never seen a diesel with any sort of intentional intake restriction, but like I said, I have never touched a car diesel of any type.

I found this in doing an internet search which seems plausible. Detroits had something similar for a while.

"The butterfly plate you mention is used as a safety device. Mercedes vents blow-by gases from the crankcase back in to the intake manifold. Being a diesel, if blow-by gets bad as the engine wears, the engine will keep running when shut off by actually running on the blow-by gases and engine oil. The butterfly valve is designed to shut off air supply, thus preventing a runaway engine."

I am currently have with a fairly standard tero cell. I am just playing around right now. Once I get comfortable with it I will try a randy cell. The tube designs interest me the most but also seem the most complicated to master. I would love to be able to make a cell produce about 14lpm under 150amps as they I could test it on my diesel at a decent 2l/cui. That should be really interesting.

You are right about the hydrogen vs hydroxy, but I still see a diesel with a spark plug igniting it if someone was to run it pure. A diesel base would be an excellent start with their fairly good durability.

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The pump very likely changes time of injection at different rpm just like gas.

[Bob]

Manta:
 Just so you know...timing on the Mercadies engine is precarious at best... to tell the truth I don't know how they run as well as they do.... because when you adjust the injection pump's timing you do it by the FIRST DRIP out of a fuel spicket that you stick in line instead of the injection line to N0#1 cylinder... it is Supposed to coenside with the timing marks on the crankshaft but you know and I know a DRIP is not the most accurate of measuring devices... so what happens is you do it about 1000 times and try to get it to be consistent at dripping at the proper time...
 When I tore into that Mercadies for my mom to try and get it running for her I was appalled at the instructions on how to time it... I couldn't believe that anyone would manufacture an engine with such a crude way of timing the engine... I found out later that you are supposed to Tune the engine by ear, to where it sounds better.... and that the drip method is just to get you in the ball park. LOL ! (this is better ? HAHAHAHA!)
 but oddly enough it does work and the engine has been running good for years although it mostly sets ,because nobody will drive it because the transmition may pop into neutral and not be able to get it into any gear ... so your stranded !
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there are 3 Mercadies engines here 2 in old cars and one to swap out of the old beastie one of these days.
  My Mom Loved that car and it got a consistant 40mpg or better all the time... it reverted back to my Sisters car after Mom died and I have been trying to get it going for her but without much luck
I think to fix it I will have to remove the trans completely... and without a shop to work in I am reluctant to do that! LOL
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I do know if the tractor engine gives up the ghost I will put the diesel engine it instead of trying to find another tractor engine.
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Brad:
 If I remember correctly Hydroxy gas HAS to be ignited it will not ignite from compression or heat which seams odd I know but that is what I remember from my reasearch, Knowing this means on a gasoline engine your safe from Pre ignition if you set your timing properly...... the problem is when Hydroxy gas does ignite it burns so fast it out runs the rest of the fuel in the cylinder (because of the extreamily fast flame front) but in a diesel it would stand to reason that the diesel when ignited sets off the Hydroxy gas and they both blow up togather
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 I may be in error in this , but its what I remember reading, I suggest checking it out yourself.
I do know Pinging with Hydroxy gas being added to the air in a gasoline engine is common. and can be alleviated by simply changing the timing to closer to TDC, it isn't because the Hydroxy gas is self igniting, but rather because the hydroxy gas makes all the fuel go up at once instead of taking time to ignite ... in other words when your timing on a gas engine is at 12 degrees BTDC and you add Hydroxy gas to the system you'll more than likely get a bad ping or pre-ignition because the hydroxy gas makes the ignition happen much faster... so changing the timing to 8degrees or even 6degrees is usually enough to cure the problem.
 it stands to reason that the same can be done for a diesel engine if problems are encountered there as well.
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Bob.....