LPG Explained... An Intro to LPG

[Beej GrpA]

It took me all of 5 minutes to find it. Where were you looking?

BP: 50/50 propane/butane, 100RON, 93MON
http://www.bp.com.au/products/LPG/lpg_product_info.asp

Shell: 50/50 propane/butane, 92MON
http://www.shell.com/static/au-en/do...g_fuel_pds.pdf

Caltex: up to 60% butane, 100RON
http://www.caltex.com.au/products_oil_detail.asp?id=179

While it's true that the mix of gases can vary specifically in any given tank of fuel, and if you get pure propane it might be 110RON, you can't tune your car for that scenario if you're just as likely to get 100RON or less. The fact is you never know exactly what you're getting, so you have to tune for the minimum guaranteed numbers - as listed above.

obviously i dont know shit about navigating a web site

obviously my calculation was incorrect 92.5 MON -> RON....100 not 102 *shrugs*

Agreed, the lowest common denominator is obviously what u do haf to tune the vehicle too, obviously the above tho does prove one point, no matter what, the producer will only ever guarantee industry standard irregardless.......but hey, 100RON at the pump is still good enough for me

now if only we could get pure propylene at the pump

[oldcorollas]

you definitely don't want propylene...

it has low vapour pressure and will often burn incompletely....
think acetylene, but an extra carbon....

i used it for carburisation tests because it cracks to produce solid carbon easily.
it was sometimes an issue keeping up tank pressure etc etc...
also was around $1000 per G bottle (but so is carbon monoxide)

[Big rob]

what you want is toluene at the pump, thats if you want to revert back to an injection of a liquid rather than gaseous supstance.

[oldcorollas]

what you want is toluene at the pump, thats if you want to revert back to an injection of a liquid rather than gaseous supstance.

somehow, i don't think that will sit well with the EPA toluene = bad for you.
since we are all obsessed with octane numbers.. why not run pure octane

injection of liquid LPG/propane is good because of the temp reduction of the ingoing air, due to vapourisation of the gas within the inlet, which would be great for SC and turbo cars
next best would be alcohols i suppose....

[Big rob]

but toluene, it smells soo good lol. ITs only mildly carcenigenic(spelling). Yes i also would really like liquid LPG injection, and that company seems to think they can do it cheaper or as cheap as current LPG carby systems installs.
I would love to see that.

[oldcorollas]

all it would take for a liquid LPG system is to have a pressure reg to keep line pressure to the injectors the same (referenced to manifold pressure as per usual), injectors that will survive when used with liquid LPG (perhaps they need to be heated also?), and something simple like megasquirt and away you go
there are issues like longevity of injector, temp of gas affecting the amount injected (as well as possibilities of vapourisation in the lines before hand (as mentioned in the link i provided ) ) etc..... what you need is a system that is suitable for a variety of environmental conditions. in australia, where it is often hot, vapour injection makes more sense. in places where it is usually cold, liquid injection makes more sense.. in terms of fuel qualities and implementation...
some liquid LPG injectors are available already, but i can't remember where... some of the MS guys were looking into/doing it a couple of years ago.

[mrshin]

Well, despite my seeming non-activity for the last little while, I am still playing around with this stuff. I have also got a set of vapour injectors on order at the moment, and will be doing a conversion with them once they arrive. Depending on how well they work, I may well be playing with several more sets soon afterwards on different engines.

[Beej GrpA]

Petroleum Gas being a liquid is a product of both temperature and pressure. couldnt u simply solve the vapour problem by keeping the pressure higher?

[oldcorollas]

thats possible, but what pressure would be required?
hmm, quick look around..

32degC = 10BAR
extrapolating data from http://www.propanecarbs.com/propane.html
60C = 20BAR
100deg = 50BAR
150DEG = 150BAR

i think you'd wanna keep it cool.... even at 32degC, can you get a pump for to provide 160psi? or at 60C, 320psi??

[Beej GrpA]

thats possible, but what pressure would be required?
hmm, quick look around..

32degC = 10BAR
extrapolating data from http://www.propanecarbs.com/propane.html
60C = 20BAR
100deg = 50BAR
150DEG = 150BAR

i think you'd wanna keep it cool.... even at 32degC, can you get a pump for to provide 160psi? or at 60C, 320psi??

well thats the question isnt it? first we figure out how hot its going to get in Ye old engine bay, then we try and insulate the lines as much as possible, and keep the pressure as high as possible

EDIT: By the way, its 14.7 PSI to a bar, not 16

[myne]

since we are all obsessed with octane numbers.. why not run pure octane

As you're probably well aware, Octane, amusingly enough has a relatively low octane rating of 100 from memory

[JustCallMeOrlando]

Haha, isn't that the point?

[myne]

Yeah, but not everyone get's Oldcorolla's little in-jokes

[oldcorollas]

well thats the question isnt it? first we figure out how hot its going to get in Ye old engine bay, then we try and insulate the lines as much as possible, and keep the pressure as high as possible

EDIT: By the way, its 14.7 PSI to a bar, not 16

i was just roughing the psi calc because pumps are usually specified in psi, not BAR. the calculations of pressures were with 100kpa per BAR

Yeah, but not everyone get's Oldcorolla's little in-jokes

actually, i meant to run pure octane because it is a highly branched molecule with pretty good burn characteristics and detonation resistance.
people add toluene to adjust shitty fuel, and sure you can run with it, it's just bad for you.
if you used straight octane then you know what you are getting....

same here for LPG, if you run straiht propane all the time, you know what you are getting and can tune for it

so.... how far can you drive on BBQ cylinders, and are Supagas outlets the only ones with pure propane? can you get a large tank to store at home?? (no not kidding)

[stradlater]

AFAIK Supa gas are the only ones that stock pure propane.

You can get a large tank to store it at home, but it'd cost you a bit I would imagine. It'd just be the same as getting a natural gas tank at home, like the one I've got..

ANd you can't drive very far at all on BBQ cylinders. hehe