DieselGas - how's it going?????

[mikecmb]

A while back I read some comments from members who had fitted lpg enhancement to there td5's. A 20/30 % power increase was claimed with tyres chirping up the driveway etc.

That was a some months ago and I wonder how its all holding together. has your engine blown up ? is it running better than ever? is it saving you money at the bowser?

Has anyone else fitted the system since ? I would love to hear any comments.

I have talked to a RAC recomended gas fitter in Perth who told me to keep away from it and that he wont do it.

MIKE:D

[mikecmb]

Just bumping this up as I realy want to find out some info before i go ahead and do it.

Mike

[Disco_owner]

Mike;

There has been many discussions on Diesel gas on these Forums, if you do a Search on Diesel-Gas you'll probably find many Threads / reponses. I don't have Diesel-Gas installed on my 300tdi purely because I wish not to place extra Load and demand on my engine.but some others may tell you otherwise .

but I found this interesting link on one of the Threads

Engine & fuel engineering - Propane enrichment for diesels (http://www.eng-tips.com/viewthread.cfm?qid=7832)

you should read it.

[DeeJay]

What we need is a long term user review. I read that disco-owner thread and its mostly 6-7 years old now. Has'nt this concept advanced a long way since?
My first hand experience has only been with 30- 40.000 klm owners. Surely diesel engines can take 20-30% extra load. Is'nt that what chipping does? Whats the diff? I cant agree with the conclusions that fumigating causes premature wear- unless chipping does too.
David

[Tank]

What we need is a long term user review. I read that disco-owner thread and its mostly 6-7 years old now. Has'nt this concept advanced a long way since?
My first hand experience has only been with 30- 40.000 klm owners. Surely diesel engines can take 20-30% extra load. Is'nt that what chipping does? Whats the diff? I cant agree with the conclusions that fumigating causes premature wear- unless chipping does too.
David
The main purpose of the LPG is to promote a total burn of the diesel fuel, which without the LPG doesn't happen, incomplete combustion creates soot (carbon) which causes wear and makes your oil so black. Diesel engines with LPG run very clean, with little or no soot, oil stays cleaner, longer, oil change periods are extended, more power produced, less pollution, less wear. So engines run cleaner and longer and give more power and torque, if I had a diesel it would be on LPG in a flash, Regards Frank.

[JDNSW]

Adding gas to diesels can be used purely to improve combustion, giving a modest increase in power and economy, less pollution, and cleaner running and hence improved engine life, as Tank says - OR it can be used, together with the excess air always present in a diesel to give in addition a substantial, even very substantial, increase in power by adding more gas, resulting in higher operating temperatures and increased stress on everything, with a likliehood of shorter engine life or even catastrophic failure. It is often difficult to know which route is being followed for any particular installation - it may change with throttle opening, and may change from one to the other with the same installation just by adjustment (or remapping). Hence history of use must be treated with caution (both the good and the bad) - there is no simple answer.

John

[Dougal]

Surely diesel engines can take 20-30% extra load. Is'nt that what chipping does? Whats the diff?

The diff is how they ignite. The conditions present in a turbo diesel prior to diesel injection are sufficient to preignite any LPG present.
Preignition returns a lot of power but is very hard on everything in the cylinder.

I too am very interested in long term results.

[Redback]

If you contact KLR Diesel Gas Australia they will give the contact details of TD5 owners that have had it done.

Baz.

[p38arover]

The diff is how they ignite. The conditions present in a turbo diesel prior to diesel injection are sufficient to preignite any LPG present.
Preignition returns a lot of power but is very hard on everything in the cylinder.


What are those conditions? Not just pressure as LPG is under much higher pressure in a tank.

Wouldn't preignition be audible? It is in a petrol engine.

[JDNSW]

What are those conditions? Not just pressure as LPG is under much higher pressure in a tank.

Wouldn't preignition be audible? It is in a petrol engine.

Pressure in an LPG tank is quite low compared to compression pressures in a diesel - like about one tenth as much (CNG is another matter!), as the Liquefied Petroleum Gas is stored in liquid form.

I don't know what the ignition temperature/pressure is for LPG, but I would point out that the compression ratios for detonation quoted for LPG are for mixtures that are at or at least somewhere near stoichiometric mixtures. In dieselgas this is not the case, and particularly at the low concentrations used to improve combustion efficiency, I suspect that detonation will not proceed at any temperature or pressure reached before injection (a good comparison is to note that an LPG/air mixture at room temperature and pressure is explosive and can be ignited only for a range of mixtures - too little and it will only burn at the igniting flame but will not propagate. The same applies in the combustion chamber, although the mixture required to propagate will be different). When I toured the power station in Roma in the mid sixties, the engines were running on dieselgas, using very little crude oil as diesel to provide ignition, with almost all the fuel being raw natural gas, which contained LPG.

I strongly suspect that the problems with dieselgas almost entirely result from its use to provide more power, with the resulting increases in temperatures and stresses.

John

[87County]

FWIW, one of our family 300tdi's was one of the very early fitments, and it has proved to be trouble free, with subtantial power increase and o/a fuel cost reduction, for in excess of 40000k...

to my old bones, it feels like there's a V8 under the bonnet :)...

steeper roadway hills that used to be 3rd or 4th gear with the std 300tdi can be done in 5th, but we do recognise that it's probably still better for the gearbox to drop back a cog on those...

the main reason I havn't fitted it to the 3.9D county is that the system works best if a turbo is fitted as well and I havn't got around to that yet.

current industrial fitments include large irrigation pumps and semis - I imagine that a real potential exists for fitment of the system to locos if the tanking problems can be overcome (diesel locos cannot haul fuel trucks coupled next to the engine at this stage)

[Dougal]

What are those conditions? Not just pressure as LPG is under much higher pressure in a tank.

Wouldn't preignition be audible? It is in a petrol engine.

The autoignition temp of LPG is 468 deg C according to the shell MSDS.
http://cms.shellgaslpg.com/files/NZ/Material_Safety_Data_Sheet.pdf

That's lower than the compression temps in a diesel and is not tied to a stoich a/f ratio.
Good luck hearing it over your average diesel engine. If you can hear it outside, it's a hell of a bang going on inside.

[JDNSW]

The autoignition temp of LPG is 468 deg C according to the shell MSDS.
http://cms.shellgaslpg.com/files/NZ/Material_Safety_Data_Sheet.pdf

That's lower than the compression temps in a diesel and is not tied to a stoich a/f ratio.
Good luck hearing it over your average diesel engine. If you can hear it outside, it's a hell of a bang going on inside.

A quick search agrees with this figure, but shows that the autoignition temperature does vary with the air fuel ratio, although only the abstract of that paper is available without paying, so I can't say whether that variation is significant, but also revealed that the the minimum auto ignition concentration is about 10% of the stoichiometric mixture. Proportions below that will not detonate.

John

[Dougal]

A quick search agrees with this figure, but shows that the autoignition temperature does vary with the air fuel ratio, although only the abstract of that paper is available without paying, so I can't say whether that variation is significant, but also revealed that the the minimum auto ignition concentration is about 10% of the stoichiometric mixture. Proportions below that will not detonate.

John

They also list an upper and lower explosive limit, presume this is at atmospheric pressure. Roughly 2% and 10% by volume.

[p38arover]

Pressure in an LPG tank is quite low compared to compression pressures in a diesel - like about one tenth as much (CNG is another matter!), as the Liquefied Petroleum Gas is stored in liquid form.

I mis-read Dougal's post. I was thinking after the turbo but before going into the cylinder.

[jx2mad]

i have recently had gas fitted to mt 300tdi. I have found an increase of 200km per tank normal now with an increase in power. When it was first fitted the 110 went like a train...a lot of extra power with increased km/tank of diesel. However the gas usage was high. I had the gas inlet pressure to the gas injector tested and it was set at 25psi. The system I have fitted is supposed to be factory set at 15psi. However after having the pressure readjusted to 15psi the advantages of gas disappeared so I bought a pressure gauge and now I have been experimenting with different pressures myself. At present I have it adjusted at around 22psi and I find I have both power and economy back, using 1l of gas per 40km. More testing to come but I feel around this figure gives me best results. Jim

[JDNSW]

They also list an upper and lower explosive limit, presume this is at atmospheric pressure. Roughly 2% and 10% by volume.

Yes, that is about right - I don't know how they vary with pressure, probably not much seeing ignition temperature doesn't seem to, although interestingly, heavy oils will ignite at room temperature if the pressure is high enough (a hazard for high pressure compressors)!

Since the stoichiometric mix is about 15:1 (I may be getting proportion by mass and proportion by volume mixed up here, but the difference is probably not that significant, seeing the molecular weight of propane is not too dissimilar from air) or 7%, the lower limit is in fact 28% (this time I calculated it instead of guessing conservatively) of it, which is about as high as would ever be used in dieselgas - suggesting that detonation is probably pretty rare.

John

[p38arover]

i have recently had gas fitted to mt 300tdi. I have found an increase of 200km per tank normal now with an increase in power. When it was first fitted the 110 went like a train...a lot of extra power with increased km/tank of diesel. However the gas usage was high. I had the gas inlet pressure to the gas injector tested and it was set at 25psi. The system I have fitted is supposed to be factory set at 15psi. However after having the pressure readjusted to 15psi the advantages of gas disappeared so I bought a pressure gauge and now I have been experimenting with different pressures myself. At present I have it adjusted at around 22psi and I find I have both power and economy back, using 1l of gas per 40km. More testing to come but I feel around this figure gives me best results. Jim

Jim, is yours computer controlled? Who installed yours?

[Dougal]

Yes, that is about right - I don't know how they vary with pressure, probably not much seeing ignition temperature doesn't seem to, although interestingly, heavy oils will ignite at room temperature if the pressure is high enough (a hazard for high pressure compressors)!

Since the stoichiometric mix is about 15:1 (I may be getting proportion by mass and proportion by volume mixed up here, but the difference is probably not that significant, seeing the molecular weight of propane is not too dissimilar from air) or 7%, the lower limit is in fact 28% (this time I calculated it instead of guessing conservatively) of it, which is about as high as would ever be used in dieselgas - suggesting that detonation is probably pretty rare.

John

Have you seen the threads I linked into this post: http://www.aulro.com/afvb/technical-chatter/50197-lpg-diesel-fumigation-4.html#post677516

[jx2mad]

My installation is computer controlled with a gas analyser in exhaust system. It was fitted by Davis in Annangrove. Jim

[mikecmb]

Thanks to everyone who replied even those who have gone off on a bit of a scientific sidetrack.:angel:

Generaly it apperars that those who have it like it .

Havent heard of anyone blowing up an engine or drivetrain.

I will now go ahead and get some quotes and find out about the Govt rebate if it is available.



MIKE:)

[JDNSW]

Have you seen the threads I linked into this post: http://www.aulro.com/afvb/technical-chatter/50197-lpg-diesel-fumigation-4.html#post677516

Yes, been looking at it for some time, but undecided whether a) it is worth it considering the increasing price of LPG, and b) whether I can afford it, and c) where would I put the tank? (I have a water tank where they usually put it).

The cost seems to be pretty outrageous for what is involved, but it does seem an elegant way of modestly increasing efficiency and power output, probably cheaper and certainly simpler than fitting a turbocharger.

John

[p38arover]

I will now go ahead .... and find out about the Govt rebate if it is available.

Yes it is. Check the Govt website and it will tell you so.

See here News from DieselGas Technologies (http://www.dieselgas.com.au/news.htm#rebate) for the link

[PAT303]

In WA there is a road transport company that runs ore in B doubles and triples that have been running LPG in there trucks for years and they last longer,use less fuel,run cooler and all over are a big improvement.They would not run it if it wasn't good,they have to much to loose.Rumbles at Dungog have fitted it to many vehicles and haven't had a worry,It is a good thing for LR's as it lowers the cylinder head temp,thats something they need. Pat

[Dougal]

Yes, been looking at it for some time, but undecided whether a) it is worth it considering the increasing price of LPG, and b) whether I can afford it, and c) where would I put the tank? (I have a water tank where they usually put it).

The cost seems to be pretty outrageous for what is involved, but it does seem an elegant way of modestly increasing efficiency and power output, probably cheaper and certainly simpler than fitting a turbocharger.

John

I thought the comments from the cat guy about extra iron and aluminium in the oil on fumigated engines might have scared you a little. There are also some pictures in another thread of a melted cummins piston from a fumigated engine.

I don't beleive there is an efficiency gain and there is nothing but hand waving to support such a claim. Remember when you're running near max power you're already a long way from max efficiency.
There is certainly a power gain to be had and in places where gas is very cheap there may be a running cost saving.

[feraldisco]

I thought the comments from the cat guy about extra iron and aluminium in the oil on fumigated engines might have scared you a little. There are also some pictures in another thread of a melted cummins piston from a fumigated engine.

I don't beleive there is an efficiency gain and there is nothing but hand waving to support such a claim. Remember when you're running near max power you're already a long way from max efficiency.
There is certainly a power gain to be had and in places where gas is very cheap there may be a running cost saving.

I suspect with systems such as these, where there are a range of fitters of different capability, using a range of systems that are still under development, there will be a range of outcomes. There's also the issue of how prone various systems are to going out of adjustment once fitted. I think I'll wait until there's been a bit more development and long-term results and the dodgy systems/fitters have been weeded out...