isuzu & LPG

The fibre optic based temperature sensors that I am aware of operate on the basis that the glass fibre expands as a result of a temperature rise. By placing the tip of the fibre near or on the heat source the expansion of the fibre is related to the temperature of the source you are trying to measure. The amount the fibre expands is detected by measuring the path length in the fibre. A form of time domain reflectomery is used to measure the expansion of the fibre, a light signal is sent down the fibre then the time taken for the signal to go down the fibre and back tells you how long the fibre is. Instead of using a pulse if you modulate the signal you can monitor the phase change which relates to path length.

The fibre probes I am aware of that use the above described method are good to 250-300C

Hmmm.....

Thermisters and thermocouples, monitoring the flame color with a camera, this i can handle.

Time domain reflectomery and detecting the phase change of light, thats a bit beyond my electronic abilities, may need to do some research.

A shame the temp range doesn't extend a bit further.

Lyle.

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Originally Posted by slug_burner

The fibre optic based temperature sensors that I am aware of operate on the basis that the glass fibre expands as a result of a temperature rise. By placing the tip of the fibre near or on the heat source the expansion of the fibre is related to the temperature of the source you are trying to measure. The amount the fibre expands is detected by measuring the path length in the fibre. A form of time domain reflectomery is used to measure the expansion of the fibre, a light signal is sent down the fibre then the time taken for the signal to go down the fibre and back tells you how long the fibre is. Instead of using a pulse if you modulate the signal you can monitor the phase change which relates to path length.

The fibre probes I am aware of that use the above described method are good to 250-300C

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then you need to become more aware

I've seriously considered diesel gas. Unfortunately can't afford it at the moment. I understood it causes the motor to run a little quieter because the fuel ignition occurs in a similar way to indirect injection diesels, because of the different ignition characteristics of diesel & LPG. I understood the power and torque increase was in part because of a more complete burn of the fuel.

I have no idea if that's correct but it made sense to me.

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Originally Posted by rar110

I've seriously considered diesel gas. Unfortunately can't afford it at the moment. I understood it causes the motor to run a little quieter because the fuel ignition occurs in a similar way to indirect injection diesels, because of the different ignition characteristics of diesel & LPG. I understood the power and torque increase was in part because of a more complete burn of the fuel.

I have no idea if that's correct but it made sense to me.

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Yes I to was under the same belief quieter in a diesel sounds attractive as does increase in power/torque.

From another perspective everyone talks about the cost and how it could buy a lot of diesel which is true enough. No one has said anything about the reduction in pollutants we are pumping into the environment or the minimisation of our carbon footprint. We seem to think that we can go on not being responsible to how we use our planet and its resources we are wrong on this one. A greater responsibilty sounds better to me and if I can reduce my inpact on the planet then thats a winner. Yes I know I could drive a Prius but they are just not good for towing which I do a lot of. My 2 cents on the subject.
regards
Garry

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Originally Posted by garryseries3

Yes I to was under the same belief quieter in a diesel sounds attractive as does increase in power/torque.

From another perspective everyone talks about the cost and how it could buy a lot of diesel which is true enough. No one has said anything about the reduction in pollutants we are pumping into the environment or the minimisation of our carbon footprint. We seem to think that we can go on not being responsible to how we use our planet and its resources we are wrong on this one. A greater responsibilty sounds better to me and if I can reduce my inpact on the planet then thats a winner. Yes I know I could drive a Prius but they are just not good for towing which I do a lot of. My 2 cents on the subject.
regards
Garry

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The claims of a better burn haven't been proven. Unburnt fuel comes out of a diesel in the form of black smoke out the exhaust. If you don't have black smoke out the exhaust then there's no gain to be made there. If you do have black smoke out the exhaust then there's a bigger problem that needs solved.

I've been in touch with people who've done DT80 and ADR79 tests on fumigated diesels.
Turns out fumigation results in higher hydrocarbon emisssions. If you run too much gas you get more CO, HC and particulates as the engine runs out of excess air.

The worse shape your before emissions are, the better scope for reduction. Just like fixing the actual problem really. So it's not the environmental salvation either.

The litre for litre replacement doesn't seem to hold. Clean32 burning 37 litres total for 300km. A well tuned county can use 30 litres for the same distance.

How about a challenge.
Lets take two NA Isuzu powered landy's dyno, fit fumigation to one and spend an equal amount on the other in any way you wish. Dyno them before and after to measure not just power and torque but also fuel consumption with the same load. Set an EGT limit of 700C at the manifold to keep things realistic.

Any takers?:)

Ohh Geez , are you guys still here talking about Isuzus on LPG

:spudniksnore::spudniksnore::spudniksnore: :wasntme:

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Originally Posted by Dougal

The claims of a better burn haven't been proven. Unburnt fuel comes out of a diesel in the form of black smoke out the exhaust. If you don't have black smoke out the exhaust then there's no gain to be made there. If you do have black smoke out the exhaust then there's a bigger problem that needs solved.

I've been in touch with people who've done DT80 and ADR79 tests on fumigated diesels.
Turns out fumigation results in higher hydrocarbon emisssions. If you run too much gas you get more CO, HC and particulates as the engine runs out of excess air.

The worse shape your before emissions are, the better scope for reduction. Just like fixing the actual problem really. So it's not the environmental salvation either.

The litre for litre replacement doesn't seem to hold. Clean32 burning 37 litres total for 300km. A well tuned county can use 30 litres for the same distance.

How about a challenge.
Lets take two NA Isuzu powered landy's dyno, fit fumigation to one and spend an equal amount on the other in any way you wish. Dyno them before and after to measure not just power and torque but also fuel consumption with the same load. Set an EGT limit of 700C at the manifold to keep things realistic.

Any takers?:)

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sheesh Dougal. even taking things out of Context AGAIN, why don’t you just go away and leave those who are interested in LPG fumigation the option of posting some informative information with out your misinformation bashing everyone.

My 37 liters for 300klm was an exercise in how much fuel I could burn without cooking things and without leaving a big trail of black smoke. as you know!! Now just go away

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Originally Posted by EchiDna

Hey Pat, sorry I think you misunderstand - I didn't mean that diesel gas is a false technology like (for example) hiclones, I meant that the gas doesn't give you any more or any different changes than what an equivalent amount of energy in the form of more diesel would also give...

what I do think is a furphy is the semi-common thinking that the increased power/torque etc is something that is akin to a free lunch - it isn't, it costs you fuel and capital expense up front (even when the government pays for the bulk of it). I still think that an equivalent amount of extra diesel (which I agree costs more per "bang" than gas) would give you the same increases with appropriate tuning.

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You are right as far as tuning etc but I didn't do any mods at all,my engine is still factory stock in every way except I got the muffler cut out,the gas made a good improvement with no other mods.One of the few reasons I think I've had such a good run with my Tdi is because I haven't fiddled with it,just good service procedures and no winding up the tune. Pat

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Originally Posted by PAT303

no winding up the tune. Pat

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I think that is Echidna's point - by adding the gas you are effectively "winding up the tune"

As Bee_utey states, the claims of some other installers/systems that the gas has a catalyst effect or allows the diesel to burn more completely are BS.

Emissions are not necessarily reduced, as the review paper I quoted a few pages back showed. Any claim of environmental benefit would need to be scrutinised. Sure you may get up to a 10% reduction in CO2, an increase in some pollutants and a decrease of others.