Polishing Fuel Tanks

[wildebill308]

From Washington State University web site  http://postharvest.tfrec.wsu.edu/pages/N6I1A

"The limit of gas to air ratios between which explosions can occur, are expressed as lower explosive limit (LEL) and upper explosive limit (UEL). Outside of these limits there is no danger of explosion. For propane they are 2.2% (LEL) and 9.5% (UEL). This means that if there is less than 2.2% propane in a room, there is not enough fuel to explode, or if there is above 9.5% propane in a room, there is not enough oxygen present to allow an explosion."

So it might be that the ratio would be to low too be a problem, Interesting.

Bill

[wolfe10]

Good.  Glad to see factual research.  Again, I don't know that it would be a problem, but sure don't want to see someone hurt with even a potentially dangerous concentration of  propane in their whole air system.

Would also be interested in any detrimental affect of hydrocarbons on all the rubber in the suspension and brake systems.  Again, no information, but questions.

Of course, if propane injections is really important, one could remove the air system intake from the engine intake manifold, block that port and fit another air filter to feed the air system. Yes, the compressor would have to work harder as it would be supplied by ambient air, not compressed, cooled air, but something to think about.

[manholt]

Bill.  Works as long as there is no introduction of oxidant on the upper limit, such as a air leak in a air bag or air brake system or re introduction in a air brake or leveling system in a non leak system!  The numbers represented is in a controlled environment...Not in a motorhome application.  Like methane, butane, iso butane, I sure would like someone other than our friend RSBILLEDVARDS to be the test dummy!

 

[dickandlois]

Carl , This discussion kind of falls into your wheelhouse. 

Propane Combustion Characteristics

            Lower limit of flammability    2.15

            Upper limit of flammability    9.60

            Flash point                         -156 deg. F

            Ignition temperature in air   920 to 1020 deg. F

            Octane number        over   100 

This means that between 2.15 and 9.6% of the total propane/air mixture must be propane in order for it to be combustible. If the mixture is 2% propane and 98% air, there will not be combustion. If the mixture 10% propane and 90% air, combustion will not occur. Any percentage of propane in a propane/air mixture between 2.15% and 9.6% will be sufficient for propane to burn. However, an improper air/gas mixture can produce Carbon Monoxide (CO) that is a deadly product of incomplete combustion.

Flash point is the temperature where the propane turns from a liquid to a vapor

Air Compressor flow rates are around 10 to 15 CFM

Injection point is at 5 psi of boost

To me one needs to know the column pressure of the LPG, the mix ratio to air across a pressure range of 5 to 25 psi. to know the ignition point, does it reach the ignition temperature point in the engine intake system of both the engine intake air supply or air compressor system where the ignition point can be obtained before the combustion point inside the engine cylinder.

Brett mentioned the effect of LPG on the suspension system. What about the brake system under heavy load conditions or breaking heat.

The Octane number would tend to clean the exhaust, but is there any point where the increased temperature would also have a determinable effect on the exhaust valves.

Have worked on NG power generator systems, but this is kind of outside anything remotely connected to my life experiences. Used flexible steel fuel lines and the oil stayed clean for a long time.

   Rich.

[erniee]

why would you take the chance of running out of fuel by going so low on maybe an inaccurate fuel gauge?

[jleamont]

RSbill, just thinking about this setup if it were on our coach. Between the turbo and air filter I have a T within the duct work, that is where my air compressor pulls clean air from. Looks like a 2" hose connected. If this only injects at certain boost ranges it should be under heavy suction and pull the propane toward the turbocharger, in theory. But what's going to win the battle, turbocharger or air compressor, assuming the compressor is also on building air? I cant imagine what propane would do if introduced into the compressor and actually compressed, I would think it would explode. Maybe the solution would be to install a dedicated air filter for the compressor and just separate it from the system?

[manholt]

Quote

 

Joe.  Part of the potential problem could be solved thru a dedicated filter and line, it would have to be a total system that would not have any possibility of cross over!  As Rich said, the bigger problem that I see, is at what temp will the LPG go BOOM and permanently damage the valves?  As RSBill said, the military is working on it ! 

You got to know the air pressure, LPG column pressure, ignition point not only at various psi, but then you also have engine heat and ambient temp and road surface temps to deal with.  I would think you would need two separate tanks that would inject the correct mix of LPG and Air....kind of like a DEF system...but the internal temp of the tanks would remain at a constant temp and not be affected by any external heat.

Wow!  This is a deep subject...a simple answer could make you a bloody fortune!   

[rsbilledwards]

I intend to have a conversation this Am with PDP on the issue and see what they have to say. I am sure they have encountered this before.  

[rsbilledwards]

Carl,

There is a dedicated metering device which is turbo boost controlled which regulates the required amount of propane. It is not a significant volume as I understand it. The valve issue has been considered. The system has been around and used for the last seventeen years.The Safari Trek group has used dozens of these to enhance the little Isuzu diesel performance to a much more suitable level.

Ernie, No fuel no go, not enough propane injected to even begin to fuel the engine. In my case, I know the fuel gauge is accurate. and have it calibrated to boot. 

[jleamont]

RSBILL, forget the propane, DW ready to slap you yet for tinkering with something else .

You met mine, every time I walk outside, I get 50 questions, she can sense it

[dickandlois]

This portion of the thread Polishing the fuel tank has gone way off that subject, but at the same time it is an interesting and potentially good source of information and the thought process.

Brett! is there a way to separate this discussion into a LP fuel injection for Diesel engines Thread ?? 

Rich.

[dickandlois]

1 hour ago, jleamont said:

RSBILL, forget the propane, DW ready to slap you yet for tinkering with something else .

You met mine, every time I walk outside, I get 50 questions, she can sense it

Joe, Lois has lived with me long enough that I just get a look and the only thing she might challenge is the outside temp and would it be easier when it cools off? and when I enter the house looking like I had spent a few hrs. in a coal mine - remember to clean up you mess !!

Rich.

[rsbilledwards]

I am sorry to have stolen this should have made another thread but Cetane brought it out and no other related comments since  B

[dickandlois]

1 hour ago, RSBILLEDWARDS said:

I am sorry to have stolen this should have made another thread but Cetane brought it out and no other related comments since  B

Do not fell that way at all - this has been a real gray matter issue and it has also expanded my knowledge of an application for LP that never has come up before !!

Rich.

[rsbilledwards]

Ok here is a follow up with PDP just a minute ago. Kieth said this has been a question for years. The answer is that the concentration of propane is so low no issue. It is a common belief that there is a higher concentration of propane than there is. He said as I thought, think about it most of the compressing to fill the system is done at idle and pre boost. Think about this, you are going to roll for something around a hundred miles on a gallon of propane gas vented through a 1/4 inch line. How much do you think that is in a concentration, not very much. It has never been a problem, or an issue. 

[rsbilledwards]

Brett, I will if it is OK now to start another thread with this topic where the later info or topic will be searchable?

[wolfe10]

1 hour ago, RSBILLEDWARDS said:

Brett, I will if it is OK now to start another thread with this topic where the later info or topic will be searchable?

Bill, that is fine.

And I sent a request to the IT department at FMCA to see if they could pick out the propane injection posts and put them in a new topic styled: Propane Injection For Diesel Engines in the engine section.

[manholt]

RSBILL. 

I understand Izuzu and TREK, also 1 gallon per 100 miles!  Is that on all Diesel engines, regardless off size or does the amount and psi go up exponentially?

[five]

What is propane???

[wolfe10]

1 hour ago, FIVE said:

What is propane???

C3H8

[rsbilledwards]

Ah Propane an otherwise hallucinogenic gas with a pungent stinky odor that burns blue and combined with diesel makes lots a power...

Carl, the foot controls consumption and I suppose from start and barely any thing to flat on the floor perhaps exponentially. The use in a coach for most probably not exponentially any more than the use of diesel. Does the consumption of diesel go up exponentially if you drive faster than the other guy, probably not. The 100 miles per gallon is, I am guessing, from over the years, the number they have arrived at  from feedback. It is going to be a function of driving style, prudent and conservative versus aggressive and h.ll bent on getting there. Boost PSI is the determining factor in the volume of propane gas delivered. That said one who drives with an indicated average boost of 10 PSI is going to get better economy than the character driving h.ll bent on getting there averaging 15 PSI of boost.

You little engine probably will get better mileage than mine but your coach is taller and heavier, but my coach is shorter and lighter with a really big engine...likely the same at the end.

[kaypsmith]

Actually propane has no smell, making it by itself very deadly. That pungent odor is actually ethyl mercaptan which is an additive to make the propane smell so that humans can smell it, therefore making it nose to detectable.

[jleamont]

Bill, I had a coworker that did a Hydrogen conversion on a Dodge Ram with a hemi. That was pretty neat, his average mpg was 36 over 40 on the highway. 1500 Ram 4 door 4x4 Big Horn edition. I believe it was distilled water and baking soda reservoirs under the hood that were electrically charged. 

[wildebill308]

16 hours ago, jleamont said:

RSbill, just thinking about this setup if it were on our coach. Between the turbo and air filter I have a T within the duct work, that is where my air compressor pulls clean air from. Looks like a 2" hose connected. If this only injects at certain boost ranges it should be under heavy suction and pull the propane toward the turbocharger, in theory. But what's going to win the battle, turbocharger or air compressor, assuming the compressor is also on building air? I cant imagine what propane would do if introduced into the compressor and actually compressed, I would think it would explode. Maybe the solution would be to install a dedicated air filter for the compressor and just separate it from the system?

On my little 5.9 the hose for the air compressor comes off the 90* elbow just at the intake not before the turbo. There is a possibility of moving the air intake for the compressor further upstream from where you might install the propane injector. I seriously doubt it would backflow very far against the intake charge.

One outher thing on my engine they show to drill into the intake on the short piece just before the casting. Well I have had that apart and it has a convoluted inner liner to diffuse the EGR gases going into the intake charge. 

Bill

[manholt]

That's been around for a long time, Joe.  If I remember correctly an inventor in Australia came up with it, but got shot down by big oil and the auto industry.  He got an unbelievable mpg and was paid off to quietly go away!

RSBill, if you want to go like a bat out of H, use Nitrous Oxide!

Kay, right you are! The only problem with ethyl mercaptan is that it leaves a dark oily residue over time.

FIVE, I know, you have a all electric coach...not to sure if the LPG system would be compatible with any engine built in 2007 or newer, due to the new EPA standards!