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What happened to propane and CNG

General engine tech -- Drag Racing to Circle Track

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dfarr67
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What happened to propane and CNG

Post by dfarr67 » Sat Nov 09, 2019 11:45 am

These fuels may still be popular in other regions but I haven't seen much use since the 90's. Has fuel injection negated the economy of converting or purchasing a CNG vehicle?

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Re: What happened to propane and CNG

Post by PackardV8 » Sat Nov 09, 2019 12:19 pm

dfarr67 wrote:
Sat Nov 09, 2019 11:45 am
These fuels may still be popular in other regions but I haven't seen much use since the 90's. Has fuel injection negated the economy of converting or purchasing a CNG vehicle?
CNG storage was always too bulky for automotive use. I have a young friend completing a doctoral thesis on converting ocean-going vessels to CNG. Bunker fuel is too dirty to be allowed being burned in many European ports and there's plenty of space down in the bowels of the ship to build in CNG storage.

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Re: What happened to propane and CNG

Post by dfarr67 » Sat Nov 09, 2019 6:20 pm

I saw a 90's Dodge van factory CNG I don't know whether the tank was liquified gas or not- used mpfi too. Scrapped the van due to fuel sender/pump? expense.

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Re: What happened to propane and CNG

Post by BigBlockMopar » Sat Nov 09, 2019 6:27 pm

I daily drive my '73 Dodge Dart on Propane/LPG with two fuel tanks in the trunk.
The fuel tanks are heavy and mounted on a steelframe, bolted to the car.

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Re: What happened to propane and CNG

Post by cjperformance » Sat Nov 09, 2019 11:01 pm

CNG is stored in a highly compressed gaseous state (3000ish psi IIRC) for automotive use, im pretty sure that the pressure requied to liquify NG is crazy high.

Propane or LPG(a mix of propane,butane,propanol,butanol,etc) is liquified at around 135psi depending on ambient temp, then expands aprox 253 times once vapourized.

LPG is still reasonably common here in Australia but due to the addition of government taxes,the improvement of new vehicle fuel efficiency and the increase in the cost of conversion kits to suit the emission requirements of newer vehicles it is becoming prohibitive in cost V return.
It is still occasionally used as a cheap fuel alternative for
occasional use street performance vehicles. I just recently fitted a 308ci holden V8 with a single turbo LPG setup, very budget basic setup, started out at 198rwhp n/a, 9psi makes 324rwhp and makes more rwhp at 3000rpm than it made n/a, cheap to set up and to run and dead simple to tune.
It is also an easy way around emission laws for late model engine conversion laws here.

Many service stations here that are being knocked down and renovated are not including LPG as a part of the renovation.
I like it as a fuel, yes it has its limitations but does have some bonuses as well.
Craig.

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Re: What happened to propane and CNG

Post by Coloradoracer » Sat Nov 09, 2019 11:11 pm

My company is going to an all cng fleet. They are more than 50% now with plans to be 100% by 2025ish... its a big deal..
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Re: What happened to propane and CNG

Post by cjperformance » Sat Nov 09, 2019 11:43 pm

Coloradoracer wrote:
Sat Nov 09, 2019 11:11 pm
My company is going to an all cng fleet. They are more than 50% now with plans to be 100% by 2025ish... its a big deal..
What type of fleet vehicles are these?
We had/have some public transport busses running CNG here. Far better than the diesel versions regarding fumes in the city run busses.
Craig.

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Re: What happened to propane and CNG

Post by Coloradoracer » Sun Nov 10, 2019 10:05 am

cjperformance wrote:
Sat Nov 09, 2019 11:43 pm
What type of fleet vehicles are these?
We had/have some public transport busses running CNG here. Far better than the diesel versions regarding fumes in the city run busses.
Trash trucks....
Mark Goulette
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Re: What happened to propane and CNG

Post by peejay » Sun Nov 10, 2019 10:38 am

dfarr67 wrote:
Sat Nov 09, 2019 11:45 am
These fuels may still be popular in other regions but I haven't seen much use since the 90's. Has fuel injection negated the economy of converting or purchasing a CNG vehicle?
We were all set to start doing CNG dual-fuel conversions where I had been working about five or seven years ago, but an expected alt-fuel tax break didn't make it through state legislature and interest folded.

The tanks are fairly large and bulky, but for fleets it makes a lot of sense for a reduced maintenance perspective (oil changes can really be drawn out since CNG puts less crap in it) and the fact that they could refuel in-house for about 75-90 cents per gallon equivalent. The conversions would have run about $10k/truck for parts and labor so they really needed the tax break to make it worthwhile.

I still like the idea because it's a lot like having a plug-in hybrid: fill up for cheap at home overnight, and if you run out it will still get you there on gasoline. Plus there are still some CNG service stations around even today.

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Re: What happened to propane and CNG

Post by cjperformance » Sun Nov 10, 2019 8:22 pm

Coloradoracer wrote:
Sun Nov 10, 2019 10:05 am
cjperformance wrote:
Sat Nov 09, 2019 11:43 pm
What type of fleet vehicles are these?
We had/have some public transport busses running CNG here. Far better than the diesel versions regarding fumes in the city run busses.
Trash trucks....
Nice, good to see clean trucks doing the dirty work!
Craig.

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Re: What happened to propane and CNG

Post by Circlotron » Mon Nov 11, 2019 1:35 am

Coloradoracer wrote:
Sun Nov 10, 2019 10:05 am
cjperformance wrote:
Sat Nov 09, 2019 11:43 pm
What type of fleet vehicles are these?
We had/have some public transport busses running CNG here. Far better than the diesel versions regarding fumes in the city run busses.
Trash trucks....
Even better if you can get the NG from the rotting trash.
Many municipal rubbish dumps are starting to use this gas to run a generator and put the power back into the mains as a way of making money. One near my place does this and has a flower greenhouse on site too. Some of the waste heat is fed to that. If only they fed the cleaned engine exhaust to the plants the CO2 and water vapour would be used by the plants to completed the cycle.

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Re: What happened to propane and CNG

Post by hoffman900 » Mon Nov 11, 2019 8:30 am

Circlotron wrote:
Mon Nov 11, 2019 1:35 am
Coloradoracer wrote:
Sun Nov 10, 2019 10:05 am
cjperformance wrote:
Sat Nov 09, 2019 11:43 pm
What type of fleet vehicles are these?
We had/have some public transport busses running CNG here. Far better than the diesel versions regarding fumes in the city run busses.
Trash trucks....
Even better if you can get the NG from the rotting trash.
Many municipal rubbish dumps are starting to use this gas to run a generator and put the power back into the mains as a way of making money. One near my place does this and has a flower greenhouse on site too. Some of the waste heat is fed to that. If only they fed the cleaned engine exhaust to the plants the CO2 and water vapour would be used by the plants to completed the cycle.
Trash gas had a lot of H2S (Hydrogen Sulfide) has which is super corrosive. Only inconel can really deal with it.

If you heat it up and quench it with water, it produces sulfuric acid as a byproduct. That’s how H2S scrubbers work. It will do similar things inside an engine.
-Bob

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Re: What happened to propane and CNG

Post by Steve.k » Mon Nov 11, 2019 11:09 am

In the great white north propane was a big rage however fizzled out. Mostly because its poorer cold start capability and most fuel injection motors with the new setups required a major revamp to hook up. Also with the engine being so protected by sensors that it caused havoc with systems. Im thinking tecs now could get around this. We also had trouble with propane being dirty and clogging vapourizers and you had to plumb coolant through these to keep from freezing. Also the propane took its toll on valves even with the hardened seats. Alot of cities here are using lng in city transit on diesel conversion but I haven't heard how the gains are as far as working lifetime of engine. We have gas compressors that run for 100000's of hrs on down hole gas with minimal scrubbing so i would imagine its good on cleaner lng.

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Re: What happened to propane and CNG

Post by Tuner » Mon Nov 11, 2019 8:35 pm

In cold weather I use propane for cold starts and cold running enrichment on a 318 Mopar that doesn't have a choke. I put a WBO2 sensor in the hole in the intake manifold where the choke thermostat would be in the exhaust crossover.

A quart bottle and propane torch (for a valve to regulate flow) connected to a tee in the vacuum line between the vac. gauge and the carb base. Watch the A/F with the LM-2 and adjust as needed. This works great and it is amazing how lean it will run and how well it runs so much leaner than it can on gasoline until the exhaust heat in the intake reaches operating temperature.

What else is interesting to see is with the sensor so close to the cylinders the reaction time to throttle position change and the lead and lag of the puddle of fuel in the manifold is very evident. The puddle does not move as quick as you would think. Visualize how long it takes rain drops to move 10 inches on your windshield and then factor in how smooth the glass is compared to the walls and floor of an intake.

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Re: What happened to propane and CNG

Post by ProPower engines » Mon Nov 11, 2019 10:48 pm

Up here in the 80's the Government was offering insurance discounts for fleets that converted to LPG.
Then 1000's of trucks in fleets all over BC converted we had 10 conversions to the fleet vehicles we had...But
they reneged and the discounts were never given. But at the time the cost of LPG was .08/Lt and a 250 Lt tank
was about $25 to fill but between the cost savings per mile driven and the savings on engine wear the conversions
were still worth the cost at the start. At that time it was depending on the tank size between $1800-$2500 per conversion.
Now we used LPG till the mid 90's when the newer cars used for cabs came along the bubble top impala's and the
Ford LTD's and it was still worth the cost to convert. Up here cab's have a 10 year life span as a cab but the cost went up steadily till about 96-99 where it really went up to almost the same cost a gasoline per Lt.. Gas was .86'/Lt V .78/per Lt
for propane fuel.
That said up here the fuel quality changed some making it more volatile and guys that had the CR bumped had issues
with detonation which never was an issue years before. But In my case we had trucks with both and the cost per mile
went up drastically on LPG because it did not have the BTU/Lb so you used almost 2 times as much depending on the brand/supplier of the LPG. It melted Cat`s and destroyed mufflers and the rest of the exhaust systems fast.
It got so bad here that any muffler shop would not warranty their systems from rot out for more then 30 days.
Even with the aluminized systems would be destroyed in under 2 years. Any of the Walker exhaust dealers would
not even put a system on an LPG fueled vehicle because they new they would be back for warranty sooner then later.

Then came 2000 and forward all the new cars and trucks while there was a fix for the ECU to run LPG the 1st rounds of vehicles were not receiving any benefit from running it. With the conversion so costly now about $3000+ anyone
would never see any cost savings in maintenance costs of fuel savings per mile driven so it just went by the way
of the doh doh bird and now the only sales for propane is RV`s for the appliances and BBQ tanks or 100lb Mobile homes
tanks.
If its all you got it will work. No its not cheaper per mile then gas but at least it does burn cleaner then other fuels.

LNG was also available in certain parts up here but the reg`s were much stiffer then LPG. The tanks had a life span
because of their high operating pressure as was the rest of the system and inspectors for one fuel could not inspect
others unless they were certif. in both then came replacement parts. You had to be ticketed to get them till there was a law suit which changed that program.

Bus`s and other city vehicles are still LNG but they are not as common as diesel fueled vehicles because they had high
maintenance costs and the fleets that are LNG powered cyl. head issues on some run rampant.
one customer at the local Mack dealer shop sends me heads from the LNG fuels engines with 6`cracks in them that
leak water damaging the rest of the engine badly when it goes wrong.

The ferries that use LNG and WTF were they thinking there Issue after issue yet to be resolved completely if ever.
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