WAS fume'ing (now more of a flaming thread...)

[vvega]

are we done yet >?
or are you still kicking the dead horse

The more you reply, the longer this drags on
Can't believe theres 5 pages more than when I read it last All I know is guys in oz use it, and while there is a subsidy from the government over there, it may not include diesel vehicles for much longer

yeah i apreciate that but im kinda hanging out that he will realise hes miscalculated

[KiwiBacon]

Autoignition point is the concerning one. 450C.

Simple question. Does the air fuel ratio have any impact on the ability of the LPG to ignite?

To burn yes, to autoignite there's nothing I've found.

[Swamped]

Could be why some of those papers mentioned having problems under high load and why they were working on a system to manage it.

[darinz]

Isn't autoignite a flash word for spontaneously catches fire?

[KiwiBacon]

as i said unless you use the correct figures .. you will get a incorect answer
below 1.9% and lpg will not ignite in open air

source : http://www.gameco.com.au/index.php?mod=page&idp=25

Yet you cannot provide the correct figures or calculations to prove either way.
That gameco MSDS is for a different mix to the automotive lpg sold here. Different UNS number and all.

That 2% is for ignition of lpg in open air from another source, a very different scenario to internally heating it 200 degrees above it's autoignition point.

Slow down, read and think. The speed that you are cutting and pasting shows you're not reading any of this properly.

I've shown it detonates, I've shown why it detonates.
Now tell me how you can stop it happening. A very lean LPG mix might be alright, but it might not.
Work out what you think is a mix that won't/can't detonate and we can work out what power that might add.

Yes autoignite is when it self-combusts.

[KiwiBacon]

Could be why some of those papers mentioned having problems under high load and why they were working on a system to manage it.

Exactly.
But "high load" is exactly what these aftermarket kits are aimed at.

It's good to see some people thinking about this now.

[vvega]

Autoignition point is the concerning one. 450C.

Simple question. Does the air fuel ratio have any impact on the ability of the LPG to ignite?

To burn yes, to autoignite there's nothing I've found.

Autoignition temperatures of liquid chemicals are typically measured using a 500 mL flask placed in a temperature controlled oven in accordance with the procedure described in ASTM E659 [1].

Gas is measured in a ideal combution state

The flammable (explosive) range is the range of a gas or vapor concentration that will burn or explode if an ignition source is introduced. Limiting concentrations are commonly called the lower explosive or flammable limit (LEL/LFL) and the upper explosive or flammable limit (UEL/UFL).

Below the explosive or flammable limit the mixture is too lean to burn. Above the upper explosive or flammable limit the mixture is too rich to burn

if it is to lean to burn it CANNOT auto ignite

[vvega]

I've shown it detonates, I've shown why it detonates. yes because you ran it to rich
Now tell me how you can stop it happening. A very lean LPG mix might be alright, but it might not. you just answered how to stop it happening and why your engine detonated all in one go
Work out what you think is a mix that won't/can't detonate and we can work out what power that might add.

Yes autoignite is when it self-combusts. but again it cant auto ignite if its to lean to burn otherwise as you heated the air that you have just sucked in there are other componds that would also be auto igniting

ok so lets say we go for 1.5 % .. so were right on the safe side

[KiwiBacon]

The flammable (explosive) range is the range of a gas or vapor concentration that will burn or explode if an ignition source is introduced. Limiting concentrations are commonly called the lower explosive or flammable limit (LEL/LFL) and the upper explosive or flammable limit (UEL/UFL).

Below the explosive or flammable limit the mixture is too lean to burn. Above the upper explosive or flammable limit the mixture is too rich to burn

if it is to lean to burn it CANNOT auto ignite

Read what you've just quoted.
Burning from an external ignition point is not autoignition. The flammability limits are not tested by autoignition.

The reasons gases can't burn when lean is because the surrounding air cools it faster than it can reach the needed temperature to burn.
When it's all at 650C in a diesel engine everything around it is encouraging ignition.

Slow down and read stuff you're cut and pasting.

[KiwiBacon]

ok so lets say we go for 1.5 % .. so were right on the safe side

We'll go with that for an example then.

Is that by weight or by volume?

[haynzy]

Isn't autoignite a flash word for spontaneously catches fire?

nope is the term for when a teenage boy has an over exciting dream about his sisters best m8

[vvega]

Could be why some of those papers mentioned having problems under high load and why they were working on a system to manage it.

Exactly.
But "high load" is exactly what these aftermarket kits are aimed at.

It's good to see some people thinking about this now.

yes but its been 20 years since then and they have sorted that issue

[vvega]

ok so lets say we go for 1.5 % .. so were right on the safe side

We'll go with that for an example then.

Is that by weight or by volume?

we will go by volume .. because that is how its rated to keep a referance
by weight we would end up with like .5% volume

[vvega]

Isn't autoignite a flash word for spontaneously catches fire?

nope is the term for when a teenage boy has an over exciting dream about his sisters best m8

flash point and autoignition are 2 different things
flash point requires the gas to be in the volumes set with th upper and lower flamable limits
auto ignition require that its above the upper limit(because it would flash if it was lower and flash is normally a lower value)... as long as there is a nekid flame or ignition sorce ... its also considered to be its most explosive/volitile
hope that helps

[Swamped]

regardless of if they sorted that issue 20 years ago its still somthing to consider for a do-it-yourselfer. Every paper I read had problems at "low load" with spitting and misfiring and detonation at "high load"...up till the most recent one of 2002. I don't take sides just let the facts show themselves. If whoever is soooo right/wrong just out and prove it in one go....stop beating around the bush cos at the moment this argument is just goin in circles.

[KiwiBacon]

Isn't autoignite a flash word for spontaneously catches fire?

nope is the term for when a teenage boy has an over exciting dream about his sisters best m8

flash point and autoignition are 2 different things
flash point requires the gas to be in the volumes set with th upper and lower flamable limits
auto ignition require that its above the upper limit(because it would flash if it was lower and flash is normally a lower value)
hope that helps

Flash point is liquid to vapour, it happens below -100C for lpg and has nothing to do with combustion.

Flammability and autoignition are also two different things. It's the difference between being set alight and spontaneously combusting.
Your last line is not right at all.

So 1.5% of air volume being LPG?

My engine in the video at idle, lets give it a VE of 80%.
700rpm
3.9 litres
works out 1092 litres per minute air consumption.

So at 1.5% that's 16.4 litres per minute of lpg.
Do we agree?

I'm off to strike up the diesel again, set the lpg hose to similar volume in that test and measure the lpg flow-rate.
Back in 15.

[J_Dub]

this thread must have broken a few records of fastest increase of posts.
Its pretty damn clear both partys know alot on the topic, and both are standing by what they are saying and have relevant points and information to back up what they are saying, so agree to disagree....
God damn, its now become a battle of egos and who has the most technical/mathmatical theorys.....
You have both made it clear you know ya shit, and have plenty of evidence to back that up... DONE

[KiwiBacon]

Okay, it didn't take 15 minutes. Here're the experiment results.

The engine running in the vid is with 1/8 turn on the gas bottle. Unfortunately I don't have a flow regulator to use.
I ran it idling and checked that twice. Severe detonation (as in the video but the camera didn't pick up the noise or shaking much) with 1/8 of a turn on the handle.

I then measured the lpg flow by using two buckets. A 10 litre bucket full of water and a 1.2 litre bucket upside down inside it full of water. Gas is bubbled through the hose and trapped in the upside down 1.2 litre bucket. When bubles escape from the little bucket and through the water to the surface, the little bucket is full (1.2 litres of gas)

It took 16 seconds to fill the little bucket.
16 seconds is 27% of a minute. Works out to be a flowrate of 4.5 litres per minute of lpg.

The engine is a four stroke diesel of 3.9 litres capacity. Assumed VE of 80% and idle speed of approx 700rpm.
The idle air consumption is:
3.9*700*0.8/2 = 1092 litres per minute.

The gas flowrate of 4.5 litres per minute gives an lpg volume ratio of 0.4%

There we have it ladies and gentlemen, audible detonation with a fumigation rate of 0.4%.
This is below the LFL of lpg and proves that detonation is not limited to the range of flammability in open air.

I welcome anyone else to repeat this experiment so we can get as wide a range of results as possible.
I estimate the margin of error on the results to be +/-50% due to the inaccurate metering of lpg. Thus the fumigation rate could have been anywhere from 0.2 to 0.6%.

[vvega]

Examples of flash points
Fuel Flash point Autoignition
temperature
Ethanol 12.8°C (55°F) 365°C (689°F)
Gasoline (petrol) <−40°C (−40°F) 246°C (475°F)
Diesel >62°C (143°F) 210°C (410°F)
Jet fuel >38°C (100°F) 210°C (410°F)
Kerosene (paraffin oil) >38–72°C (100–162°F) 220°C (428°F)
Vegetable oil (canola) 327°C (620°F)[1]
Biodiesel >130°C (266°F)

Gasoline (petrol) is designed for use in an engine which is driven by a spark. The fuel should be premixed with air within its flammable limits and heated above its flash point, then ignited by the spark plug. The fuel should not preignite in the hot engine. Therefore, gasoline is required to have a low flash point and a high autoignition temperature.

Diesel is designed for use in a high-compression engine. Air is compressed until it has been heated above the autoignition temperature of diesel; then the fuel is injected as a high-pressure spray, keeping the fuel-air mix within the flammable limits of diesel. There is no ignition source. Therefore, diesel is required to have a high flash point and a low autoignition temperature.

Diesel flash points vary between 126°F and 204°F (52°C-96°C/WJ). Jet fuels also vary greatly. Both Jet A and jet A-1 have flash points between 100°F and 150°F (38°C-66°C/WJ), close to that of off the shelf kerosene. However, both Jet B and FP-4 have flash points between -10°F and +30°F (-23°C - -1°C/WJ)

The flammable (explosive) range is the range of a gas or vapor concentration that will burn or explode if an ignition source is introduced. Limiting concentrations are commonly called the lower explosive or flammable limit (LEL/LFL) and the upper explosive or flammable limit (UEL/UFL).

Below the explosive or flammable limit the mixture is too lean to burn. Above the upper explosive or flammable limit the mixture is too rich to burn. The Auto-Ignition Temperature is not the same as Flash Point - The Flash Point indicates how easy a chemical may burn.

[vvega]

Okay, it didn't take 15 minutes. Here're the experiment results.

The engine running in the vid is with 1/8 turn on the gas bottle. Unfortunately I don't have a flow regulator to use.
I ran it idling and checked that twice. Severe detonation (as in the video but the camera didn't pick up the noise or shaking much) with 1/8 of a turn on the handle.

I then measured the lpg flow by using two buckets. A 10 litre bucket full of water and a 1.2 litre bucket upside down inside it full of water. Gas is bubbled through the hose and trapped in the upside down 1.2 litre bucket. When bubles escape from the little bucket and through the water to the surface, the little bucket is full (1.2 litres of gas)

It took 16 seconds to fill the little bucket.
16 seconds is 27% of a minute. Works out to be a flowrate of 4.5 litres per minute of lpg.

The engine is a four stroke diesel of 3.9 litres capacity. Assumed VE of 80% and idle speed of approx 700rpm.
The idle air consumption is:
3.9*700*0.8/2 = 1092 litres per minute.

The gas flowrate of 4.5 litres per minute gives an lpg volume ratio of 0.4%

There we have it ladies and gentlemen, audible detonation with a fumigation rate of 0.4%.
This is below the UFL of lpg and proves that detonation is not limited to the range of flammability in open air.

I welcome anyone else to repeat this experiment so we can get as wide a range of results as possible.
I estimate the margin of error on the results to be +/-50% due to the inaccurate metering of lpg. Thus the fumigation rate could have been anywhere from 0.2 to 0.6%.

quote interesting but you cannnot disporve the flamibility facts . the simply must be somethign worng in your testing
is this still on a n.a engine ?

wanna go tri to rev it or tun back the gas to the point of no preignition ?.. then measure that

[KiwiBacon]

quote interesting but you cannnot disporve the flamibility facts . the simply must be somethign worng in your testing
is this still on a n.a engine ?

wanna go tri to rev it or tun back the gas to the point of no preignition ?.. then measure that

I just have proven through experiment that the lower flammability limit does not apply to autoignition.

A rough translation is game, set & match.

I suggest you try it yourself and stop posting up irrelevant crap from google.

[vvega]

no you havent proven anything what so ever
and its not irelevent crap it shows you dont actually know what your talking about
how can you create a experiment to prove or disprove anything when you dont even understand the defitinon of the words your useing

what a waste of time i honestly thought you might give this a proper go but really i was expecting to much

basically what your trying to say is that you have now disproven years of science fact .. what do you have a Phd ?
what next .. you gunna say you just flew to the moon... what a waste of my time
jesus christ

[Steve_t647]

Be very carefull, there are a couple of things to be wary of:

I think the detonation effect you are getting is due to the lack of air in the intake, with the LPG system that I saw there was a standard air intake, an lpg expansion chamber and the LPG was drawn from it, the flow rate was also not constant it was 8% at WOT.

Also were you were doing maths on a single cylinder volume? you are ment to work on fuel volume you may find your 1/8 turn was actualy about 32% but with the engine not drawing it from an expansion chamber with additional air also it could have been much higher as the LPG under pressure pushed the air out of the system.

If you are putting in excess fuel LPG sinks so make sure (and it looks like you were) you are in an open area.

Edit for spelling

[haynzy]

The only thing proven here is that some people have way too much time on their hands

[vvega]

The only thing proven here is that some people have way too much time on their hands

agreed
time to walk away from this as its pritty obvious that hes simply not able to achieve what others have
its just sad bloddy sad

[KiwiBacon]

Be very carefull, there are a couple of things to be wary of:

I think the detonation effect you are getting is due to the lack of air in the intake, with the LPG system that I saw there was a standard air intake, an lpg expansion chamber and the LPG was drawn from it, the flow rate was also not constant it was 8% at WOT.

Also were you were doing maths on a single cylinder volume, you may find your 1/8 turn was actualy about 32% but with the engine not drawing it from an expansion chamber with additional air also it could have been much higher as the LPG under pressure pushed the air out of the system.

If you are putting in excess fuel LPG sinks so make sure (and it looks like you were) you are in an open area.

The 1/8th turn on the gas bottle was measured at approx 4.5 litres per minute. I'm not sure how you're getting 32% from that, the ratio is 0.4%, 242 litres of air to each litre of lpg.
The maths used the entire engine displacement (4 stroke so 2 revolutions for 3.9 litres).

[KiwiBacon]

The only thing proven here is that some people have way too much time on their hands

agreed
time to walk away from this as its pritty obvious that hes simply not able to achieve what others have
its just sad bloddy sad

You've got the opportunity to take it like a man and admit defeat.

It's up to you.

[DieselBoy]

Okay, it didn't take 15 minutes. Here're the experiment results.

The engine running in the vid is with 1/8 turn on the gas bottle. Unfortunately I don't have a flow regulator to use.
I ran it idling and checked that twice. Severe detonation (as in the video but the camera didn't pick up the noise or shaking much) with 1/8 of a turn on the handle.

I then measured the lpg flow by using two buckets. A 10 litre bucket full of water and a 1.2 litre bucket upside down inside it full of water. Gas is bubbled through the hose and trapped in the upside down 1.2 litre bucket. When bubles escape from the little bucket and through the water to the surface, the little bucket is full (1.2 litres of gas)

It took 16 seconds to fill the little bucket.
16 seconds is 27% of a minute. Works out to be a flowrate of 4.5 litres per minute of lpg.

The engine is a four stroke diesel of 3.9 litres capacity. Assumed VE of 80% and idle speed of approx 700rpm.
The idle air consumption is:
3.9*700*0.8/2 = 1092 litres per minute.

The gas flowrate of 4.5 litres per minute gives an lpg volume ratio of 0.4%

There we have it ladies and gentlemen, audible detonation with a fumigation rate of 0.4%.
This is below the LFL of lpg and proves that detonation is not limited to the range of flammability in open air.

I welcome anyone else to repeat this experiment so we can get as wide a range of results as possible.
I estimate the margin of error on the results to be +/-50% due to the inaccurate metering of lpg. Thus the fumigation rate could have been anywhere from 0.2 to 0.6%.

OMG, you claim this to be a scientific experiment??? Spose you fella's are only engineers (dig dig dig at vvega )

Your method is incorrect, especially as you are trying to prove a preconcieved hypothysis.

First of all, you need to be sure you have an accurate way of measuring the flow rate. We have assertained that the flow rate is potentially critical to ensuring the correct air to fuel ratio in the combustion chamber.

Therefore we need to be able to accuratly measure the flow that you are alowing to enter your engine.

Gauging the flow via a bucket is a scientific experiment in itself. Its a pretty cunning idea, but not at all suitable for this sort of experiment.

First of all you need to be able to acurately measure the flow rate of the LPG.

The other critical error in your "experiment" is that your are introducing the LPG into a very old technology, cold, N/A engine, with pre-comp swirl chambers, a timed -preheat system, at idle with limited control over the flow rate of the gas.

It has already been acertained that LPG fumigation does not work effectivley in the above sort of engine.

Therefore, your method is again floored, in that you do not have the correct equipment to accurately carry out the experiment.

I personally don't think you have proved much with your experiment, apart from that fact that you are doing it wrong.

I'm surprised someone hasn't dug up some tech info on the kits that everyone's using with success????

Mite go hunting for some

[KiwiBacon]

OMG, you claim this to be a scientific experiment??? Spose you fella's are only engineers (dig dig dig at vvega )

Your method is incorrect, especially as you are trying to prove a preconcieved hypothysis.

Nope. It's measuring the fumigation rate necessary to provide audible detonation.

First of all, you need to be sure you have an accurate way of measuring the flow rate. We have assertained that the flow rate is potentially critical to ensuring the correct air to fuel ratio in the combustion chamber.

Therefore we need to be able to accuratly measure the flow that you are alowing to enter your engine.

Gauging the flow via a bucket is a scientific experiment in itself. Its a pretty cunning idea, but not at all suitable for this sort of experiment.

First of all you need to be able to acurately measure the flow rate of the LPG.

You've just said the same thing 4 times. Measuring the flow is as accurate as stated, hence the range stated in the results. This is standard practise in experiments.

The other critical error in your "experiment" is that your are introducing the LPG into a very old technology, cold, N/A engine, with pre-comp swirl chambers, a timed -preheat system, at idle with limited control over the flow rate of the gas.

It has already been acertained that LPG fumigation does not work effectivley in the above sort of engine.

Mr Dieselboy, you have outdone yourself.
This engine is not cold.
This engine is not NA (you can see the turbo in the video).
This engine has no swirl chambers, it is direct injection.
This engine has no preheat system.



Please state your credentials for critiquing this experiment.

Like your other cheerleaders, I suggest you take defeat like a man. If indeed you know how.

[Andrew1706]

I dont see how you can compare a properly designed and controlled system with prior R&D with a 5 minute 'shove a hose up the intake' experiment.

You already seemed like a dick, but to try and do something like that and then to go on defending yourself and asking people to admit defeat (like it's actually a fight?) just goes to proves it.