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Compressed Natural Gas (CNG) on RVs or TV?


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#1 dartmouth01

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Posted 12 March 2012 - 01:38 PM

A co worker just installed a CNG add on kit into his gasser pickup. He is able to run on both CNG or regular gas via the flip of a switch. Based on current costs, he will recoup what he spent on the kit in about 900 miles. Now, he commutes a pretty good distance for work, and knows where the CNG stations are, so it makes sense for him. Just wondering, anyone out there running a CNG hybrid system for RVing, or have any thoughts on it? I'm thinking I might add it to my diesel TV after the warranty runs out (apparently there is a diesel kit available as well).

#2 Stanley P. Miller

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Posted 12 March 2012 - 02:28 PM

What kind of range do you get with compressed gas? Liquid gas stores the same energy in a smaller space so I'd worry about the energy density.

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#3 mptjelgin

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Posted 12 March 2012 - 08:22 PM

I worked for a governement agency where all vehicles were converted over to CNG (with gasoline backup). The CNG range was terrible, and that was after they had taken up most of the trunk or much of the bed space with a CNG tank. We could taka sedan with a full CNG tank, and have to switch over to gasoline within 80 miles. Storing any fuel as a gas is relatively inefficient.

As a short-range urban vehicle that can be filled up regularly, CNG makes some sense. For longer range travels it doesn't seem to make much sense.

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#4 pinger

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Posted 12 March 2012 - 08:41 PM

Alot of the larger citys in Cali have been using CNG in their busses for 20+ years..You loose approx. 20% power vs gasoline but the cost is about 1/3. It takes a HIGH pressure tank to operate but there were enough filling stations around our area that is was no problem in filling up.

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#5 dartmouth01

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Posted 12 March 2012 - 09:07 PM

Yeah, my co worker has a couple stations between his house and work, so it works for him as a daily commuter (except having to fill up more often). he found a couple tanks from a CNG van in the junkyard, and bought a kit online for around $500. He's still in the testing phase, but it works, and I'm pretty impressed. Normally, when you hear of aftermarket addons for cars to improve mileage, they generally don't. I just found out another friend of mine works for some government agency in Jersey that does CNG conversions on govt trucks, so I plan on talking with him. Apparently there are some issues with engine knock due to heavy distillates depending on where you fill (refinery gas and landfille gas can screw up the engine bad, apparently). I probably won't convert my truck since it needs to be dependable, but I think the idea is great for commuters (and may have to be a side project some day for me). If gas prices keep going up, I can see this technology being more useful for the common person....

#6 Sigzy

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Posted 12 March 2012 - 10:41 PM

I retired from a Natural Gas Company and several years ago they converted the fleet to Natural Gas basically for PR reasons.As stated above power was down and range was very limited for the amount of space the tanks took up.After 2 years of trying different things to increase power and range they gave up.I understand the technology for power loss is better now but not much has been accomplished to increase range.
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#7 Leadfoot

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Posted 12 March 2012 - 10:56 PM

I worked for a governement agency where all vehicles were converted over to CNG (with gasoline backup). The CNG range was terrible, and that was after they had taken up most of the trunk or much of the bed space with a CNG tank. We could taka sedan with a full CNG tank, and have to switch over to gasoline within 80 miles. Storing any fuel as a gas is relatively inefficient.

As a short-range urban vehicle that can be filled up regularly, CNG makes some sense. For longer range travels it doesn't seem to make much sense.

Mark


Well said - especially the part about the CNG tank/s . . . . isn't anyone here old enough to remember the "gas crisis" in the 70s, and the various companies doing propane conversions?

You could have dual fuel, but it wasn't as efficient as "straight" propane - and of course, the "filling" stations were/are everywhere!
No lines, odd & even days, etc.

Two of *my* co-workers converted to propane power (not dual-fuel).

One had a 454 Chevy SB pickup. (The tank took up most of the bed.)
He towed a 5th & was able to find propane almost anywhere - but still had to plan his trips with consideration for bulk plant locations for the best prices.

He kept it a number of years, then converted it back to gasoline - and sold it.
At some point the new owner thought it was time to rebuild the engine, tore it down - and was amazed at how clean it was internally.

Second guy had a Dodge van (318 V8) with a large tank in the rear of the van (Yikes! yes it was - inside!).
he kept that a few years, then also converted it back to gasoline and sold it.

There were also a lot of propane powered cars running around - trunk was "full" of propane tank.

Main advantage of Natural Gas over propane - the Nat Gas is lighter than air (less of a fire hazard).
Main disadvantage/s - limited capacity, it must be compressed, no fill stations in place.

Run out of fuel?
"Ahhhhh - AAA - I'm out of 'gas' - - could you bring me a 'gallon' of CNG please?" .:P

I spend a lot of time in those big So. CA cities - and, yeah a few bus lines run CNG - but only *if* they are close to the refueling depot. Diesel is still "king".

Even a few USPS Offices tried it (briefly).
The one in the city where I worked was part of the test - the std postal vehicles simply didn't have enough room for the tanks & mail too!

Bottom line - CNG fill stations are few and far between - the size of the tank/s - for even short range travel - are a PITA (eat up avail space - big time).

OK for a city bus - or if you *don't* need the bed of your pickup - - but it's not gonna work for your Honda Fit, Ford Focus, Mini Cooper, or Smart Car, LOL!

Sooooo . . Plan B is . . . . . ???..:blink:


BTW - it's *not* DIY electric vehicle!
BIL has a DIY electric pickup. His design and conversion. Bed full of wet cell batteries.
Range is "maybe" 15 miles, then long time to re-charge.
Yeah - he should have known better, LOL

.

Edited by Leadfoot, 13 March 2012 - 03:54 PM.


#8 Rif

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Posted 12 March 2012 - 11:33 PM

I'm thinking I might add it to my diesel TV after the warranty runs out (apparently there is a diesel kit available as well).

I was intrigued so I did a little research. Here's what one conversion manufacturer says is required.


All diesel engines can be converted to natural gas. The power level of the engine after conversion depends on numerous issues, such as natural gas quality, power level of the original diesel engine, emission levels required etc. A properly converted engine can make as much power using natural gas as on diesel. Diesel engines converted to natural gas generally require added components as well as some mechanical changes to the engine. Basically the diesel engine undergoes a complete rebuilt and is in the process transformed from a diesel engine to a gas engine.

Conversion Steps
1- Disassemble engine.
2- Checking components and replace as necessary.
3- Modify pistons for gas use (lower compression ratio).
5- Modify cylinder head for spark plugs.
6- Install camshaft sensor and timing wheel.
7- Reassemble engine.
8- Install throttle body, ignition system, gas mixer or fuel injectors.
9- Tuning of the engine (fuel and ignition).


Sure doesn't sound like anything I would want to do to my diesel TV........
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#9 dartmouth01

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Posted 12 March 2012 - 11:36 PM

Hmm, should be able to do that in an afternoon..... :D

I was intrigued so I did a little research. Here's what one conversion manufacturer says is required.


All diesel engines can be converted to natural gas. The power level of the engine after conversion depends on numerous issues, such as natural gas quality, power level of the original diesel engine, emission levels required etc. A properly converted engine can make as much power using natural gas as on diesel. Diesel engines converted to natural gas generally require added components as well as some mechanical changes to the engine. Basically the diesel engine undergoes a complete rebuilt and is in the process transformed from a diesel engine to a gas engine.

Conversion Steps
1- Disassemble engine.
2- Checking components and replace as necessary.
3- Modify pistons for gas use (lower compression ratio).
5- Modify cylinder head for spark plugs.
6- Install camshaft sensor and timing wheel.
7- Reassemble engine.
8- Install throttle body, ignition system, gas mixer or fuel injectors.
9- Tuning of the engine (fuel and ignition).


Sure doesn't sound like anything I would want to do to my diesel TV........



#10 Mark & Dale Bruss

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Posted 13 March 2012 - 04:09 AM

Based upon energy density, an equivalent fuel load on a road tractor (Semi) would have a range of about 250 miles compared to a normal range of 1200+ miles with diesel. That is why there are proposals to make sure there are CNG refilling stations on the Interstates.

I guess no one asked the truck drivers, who get paid by the mile, not the hour, how they would like to be in a fuel station two or three times a day.

And what will the cost economy be once the same road taxes are applied to CNG as diesel?

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