What sence does it make to add more parts the compression ignition engine is reliable, and more efficient than spark type why go with the lesser of the efficiencies.
And ignition will only take place when the fuel is introduced into the compressed cylinder… That is controlled by camshaft as a rule…
I would love to see you try to use LPG through a carb… but from a safe distance…
Carryfast:
Big Jon’s dad:
Brentanna:
And a diesel engine compresses to?
depends on the engine but normally under 250psi
So LPG compresses to 600psi before it ignites without a spark and diesel engines only compress to 250psi.
Let us assume that we only want to use diesel engines for whatever reason.
The LPG won’t ignite if we simply used LPG in a diesel engine, will it Carryfast?
But diesel would ignite wouldn’t it? So if we were really clever, we could use LPG, CNG, LNG or horrors…petrol, and add just a little bit of diesel. As none of the fuels except the diesel will ignite at below 250psi we need the diesel to provide a spark to replace the spark plug that would normally be needed to use the other fuels.
Never mind your preference for 2 strokes or superchargers or any other distractions, stick to the point.
I can’t recall without looking back at previous posts but is any of the above wrong?
If LPG can withstand and sustain correct combustion,under diesel engine type cylinder pressures,without detonation issues,then why bother with petrol or diesel and why not just use spark ignition engines running at diesel engine compression ratios.That way you don’t need to use expensive diesel to act as an ignition pilot instead of a spark plug
.Simples.
Care to have another go paying particular attention to the bits in red this time?
I think its done BJD
Brentanna:
I think its done BJD
Don’t bet the farm. 
Bed time for me as I have work in the morning.
I expect we’ll see more 
later.
Big Jon’s dad:
Brentanna:
I think its done BJDDon’t bet the farm.
Bed time for me as I have work in the morning.
I expect we’ll see more
What’s the farm worth .
ok but your last link stated LPG compression ratio engines are 15:1 and the diesels here are 16:1 dont know if that is a reliable link, who are they what do they do ? The link I have provided are from university studies and experiments by respected individuals in their fields. I like Dave already have the answer and a link to it. Done by one of the most respected organizations in the field of fuel and combustion.
One suggestion go to the Nasa site check out the site and you will find all the answers you need for the properties of every type of fuel known to man. including their ignition temps and comressability.
read your link and went to their site they are talking cars not heavy trucks any idiot knows truck engines are built heavier than those used in cars. It is a matter of economics and production. Get back on topic we are talking trucks on Natural Gas you know the stuff comes out of the ground basically dinosaur ■■■■ and water formed methane now we can burn it in our homes and trucks.
Brentanna:
One suggestion go to the Nasa site check out the site and you will find all the answers you need for the properties of every type of fuel known to man. including their ignition temps and comressability.
Unlike you I don’t base everything I say on the exact contents of every website.I go by memory having been there and done it.15:1 CR was an educated rough guess from memory and that figure given in that site was confirmation that both them and I are in agreement when it comes to knowing a bit about vehicle engineering.
But you can keep your NASA theories and figures because they’re good at their job,(which is’nt making trucks),and I’d probably still be just as good at doing mine as I was over 30 years ago.
yes but sticking to 30 old technology and ideas doesnt that kind of leave you behind when it comes to new technology such as this. We are already using Natural Gas in trucks it isnt threory it is being done and used by a number of companies. Volvo is testing a whole new line of engines based on this technology, so is General Motors, and Caterpillar. It is working with existing engines. That link you put up is 3 years old already, old thought old ideas. Try reading some of the newer data and technological profiles. New engeneering studies and testing open your eyes to a whole new world of understanding.
Carryfast:
Unlike you I don’t base everything I say on the exact contents of every website.I go by memory having been there and done it.
Um, no… You base what you say on crap… You post such ■■■■■■■■ on any subject and such ridiculous opinion based outside of all reliable fact.
Stobarts are currently testing 5 Volvo FM with duel fuel. 1 @ Leeds, 1 @ Sherburn in elmet and 3 @ Crick. Only 4 places we can fill up at the moment. Flamstead, Severn view, Lymm and Castleford. I drive 1 at crick and have found them to run quite well. Running out of gas is a bit of a problem as they are only fitted with a 135 litre diesel tank. We are definately not the first to run the duel fuel idea as such. However i am led to believe that these trucks are the first in the UK to be fully integrated into the vehicles diagnostic system. Not an after factory fit.
do you really notice any huge difference from the just diesel units as for power, acceleration, engine braking ect ? Its good to have someone here who is actually driving one of the volvo’s. Have all kinds of questions if you have soem time to give us the answers.
So far i’ve not noticed any power loss. if anything it seems to pull slightly better up hills when fully loaded. my old truck was a 60 plate volvo 480 FH. same engine in the FM. only problem i’ve encountered so far is the gear change is off slightly. when loaded the change up through the box ( fully auto ) seems a bit “clunky” as if the engine sort of blips the accelerator in mid shift. bring the question on, i’m back @ work tomorrow.
the Volvos are they using a 95% with 5% diesel when over fully to NG ? What is the noise vibrations like about the same or do you find they run a bit smoother?
if it wasn’t for the in cab indicator u wouldn’t know you were runnin on LNG ( gear change issues aside ) from what volvo told us the split is nearer 30 70 in favor of gas. but that changes according to the payload.
what are the RPM parameters do the NG engines run at higher revs or about the same what would the rpm variation be for shifts.
but that changes according to the payload
naturally you will achieve more low end torque from a high diesel content.
Brentanna.
I saw this and couldn’t resist.
Remind you of anyone…■■?
ps. My race bikes run at 15+:1 CR and I wish they would carry on running and self combust when a plug goes down, the failure rate of plugs is much higher in recent years.