Propane injection good idea or bad idea ?.

[Dougal]

why would anyone inject propane into an idling diesel? what purpose is this expected to fill?

It shows that it detonates inside a diesel and does so at concentrations which many think it won't even burn at.

At idle the background noise and vibration are low enough that you can see and hear what's happening. Injecting under load in a moving vehicle, there's a lot you miss.

 

[crushers]

okay, it was a test to prove that too much will do damage. agreed.

if you are running 14 lbs of boost at 3500 rpm and injecting 3cfm will you get detonation? i do not have the ability to answer this question other than to say i have not experienced any detonation.

 

[Dougal]

okay, it was a test to prove that too much will do damage. agreed.

if you are running 14 lbs of boost at 3500 rpm and injecting 3cfm will you get detonation? i do not have the ability to answer this question other than to say i have not experienced any detonation.

What size engine?
Intercooled?
Is that 3 CFM at ambient (introduced upstream of turbo) or 3 CFM at boost pressure (introduced downstream of turbo)?
With those I should have enough info to run the numbers.

 

[crushers]

Cool,
lets do both the 3.5L and the 4.2L
3.5 is intercooled
4.2 is not
both are injected into the feeder tube from the airbox to the turbo.

 

[Dougal]

Cool,
lets do both the 3.5L and the 4.2L
3.5 is intercooled
4.2 is not
both are injected into the feeder tube from the airbox to the turbo.

3 CFM is 85 litres/min.
A 3.4L engine with 14psi boost and intercooler will have air in the intake about 1.7 time denser than atmospheric.
With 80% VE and 3500rpm I get 8092 litres/min air consumption.

85/8092 = 1.05% fumigation (by volume). That's ~2.5 times higer concentration than my experiment in the video.

A 4.2L engine with 14psi boost and no intercooler, the density ratio is about 1.5.
With 80% VE and 3500rpm I get 8820 litres/min

85/8820 = 0.96% fumigation (by volume) so about 10% less than above.

Any chance you've got a welding gas regulator that displays gas flow?
It'd be very interesting to run a similar experiment on your IDI engines. I suspect the prechambers will suck enough heat out of the cylinder compression that you'd need more gas to detonate at idle than my DI engine does.

 

[BEE-JAY42]

Was that a proper LPG carby setup, it looked like it was just feed in through a hose stuck in the intake?

 

[Dougal]

Was that a proper LPG carby setup, it looked like it was just feed in through a hose stuck in the intake?

There are no proper lpg carby's on diesels. Just jets dumping gas into the intake system. How it's delivered doesn't matter as they all get well mixed by the time it hits the manifold.

Yes that's a hose up the intake, the gas passed through the air filter, then the turbo.

 

[crushers]

well, i will disagree here. if the system is properly setup then a controlled flow will be supplied. the system i USED to sell was the best on the market in terms of design.
the more boost, the more propane was injected up to a max as per setting. so no propane was added at low boost application but once you reached a preset boost pressue the system would start supplying small amounts of propane, as the boost went up then the propane supply increase to (usually depending on the setting) 3 cfm.

just dumping propane into the system will work but i can see serious repercussions from doing so.

 

[Dougal]

well, i will disagree here. if the system is properly setup then a controlled flow will be supplied. the system i USED to sell was the best on the market in terms of design.
the more boost, the more propane was injected up to a max as per setting. so no propane was added at low boost application but once you reached a preset boost pressue the system would start supplying small amounts of propane, as the boost went up then the propane supply increase to (usually depending on the setting) 3 cfm.

just dumping propane into the system will work but i can see serious repercussions from doing so.

Sounds like you had one of the smarter systems. There are a lot that simply dump a set volume of gas whenever the switch is on.

Something else that will interest you.
3cfm of propane is approx 120 kw worth of fuel. If you have a 33% efficient engine then that's 40kw worth of shaft power and 80kw worth of heat (exhaust, radiator etc).

It's equivalent to burning an extra 11.1 litres/hour of diesel.

 

[crushers]

that would be a lot of fuel...
on my 1997 HZJ75 pickup i had the turbo and the PI system. i set the propane to come on at 10 lbs of boost and the max turbo boost at 14 PSI. with 35" boots, 3" lift and cruising at highway speeds i used 2 X 20 lb bottles of propane from Calgary Alberta to Pismo Beach California. (22 +/- hours driving)
what this shows is the system only allowed propane to come in when climbing hills or passing. as soon as the boost started to drop the propane would reduce in volume.

you could deffinately feel the power increase as the propane came on. that particular truck setup would pull hard and strong from 1400 rpm to over 4000 rpm, it wasn't a V8 gasser but those that rode in it were extremely impressed with the drivability.

you could cruise down the highway at 160 k/h and accelerate if you wanted to, under hard acceleration you could break 35" boots loose going into second gear or you could crawl through the bush at 400 rpm, of all the systems i have built or driven it was this one that brought me the most pleasure.

i never had overhearing issues, the EGTs seldom saw 1400F even on long hills... this was after i dialed the system in both fuel supply and propane supply.

i suspect that propane, if not controlled properly, can severly damage an engine in very short order.

i would not use propane for any reason other than power increase. there is a lot of misinformation floating around the net but like anything else in life, common sense needs to be used when applying propane injection to a vehicle.

 

[Otterav]

Even much more power that you get from a engine .. it wears a little more .. Actually I not take the comp measurements of my engine, but I'm 100% positive that it have less comp since I install my turbo in my 2H ..

I good friend here ( and also Mud member ) run a Propane kit in his 105 1HD-T ( swaped engine ) Cruiser ..

If you don't remove the turbo to intake pipe when you do the compression test your results will indeed be lower.
The turbo is a restriction, a hot leakdown(differential compression) is much more informative!
Hola
eric

 

[JoeCanadian]

*crushers, I'm very interested in the setup you have mentioned. do you have a parts list ans some pics?
i have been thinking about the for a long time and think that it sounds reasonable to me. do you use a bbq tank or a forklift tank? more in, i need more info.

thank Les from CLIMAX WELDING

 

[crushers]

nah, i have one kit that i installed on my PZJ70 using a barby tank so i can also run a cook stove off it. one tank usually lasts me about 6 months of DD in the winter.

i will see if i can dig up the info again;.

 

[veiloctane]

nah, i have one kit that i installed on my PZJ70 using a barby tank so i can also run a cook stove off it. one tank usually lasts me about 6 months of DD in the winter.

i will see if i can dig up the info again;.

How’s this setup working for you. I would love to see how you have it all setup