CNG in a tow vehicle?

[Jeremy Mitchell]

I am kicking around the idea of buying a truck and hauling cars, bikes or whatever somebody will pay me to transport once I get out of the army.  I have been looking into running a CNG (compressed natural gas) supplement with diesel.  I am partial to GM, so a Duramax is what I would probably go with since IMO Ford hasn't made a good diesel since the 7.3 and Dodge has a Cummins...........other than that I am not a fan.  I have joined a couple different forums asking for info but haven't really gotten any help (maybe they don't like newbs).  Anyone here running CNG in a tow rig or any vehicle for that matter?  Also if anyone has tips or info on the transport industry I would be all ears since I am thinking about completely changing my career, after I part ways with the government.

[Gsun]

No experience with CNG, but , FWIW, I have a GMC 3500 Duramax with the Allison and love it! I have over 200K (KMS) on it and no trouble except when I got a whole bunch of water in the fuel and had to do two injectors. I haul trailers with it and it does not lack power. Had a Ford Power Stroke and never again! That thing was a drain on the wallet for too long.

[Cholla]

The Duramax is an Isuzu engine.
I don't see any reason not to use CNG. Trucking companies have been doing it for years.

[Conrad]

I have a '03 Chevy w/Duramax and Allison trans. Never had a lick of trouble and it runs great. 20mpg hwy non towing, 12mpg hwy towing a 4 ton 5th wheel (65 - 70mph).

Sorry, no experience wtih CNG.

[connie_rider]

Not a Diesel Owner.
Brother-in-law has the Dodge.
Says he gets 22-24 MPG.
Seems like better mileage than I've heard the Ford/Chevy get...
With what your planning to do, I don't think you wil be towing max loads?
I would think mileage is more important than absolute towing power?

Another Question: Why use CNG?     It's not as readily available on the road as Diesel..



Ride safe, Ted

[Jeremy Mitchell]

Not a Diesel Owner.
Brother-in-law has the Dodge.
Says he gets 22-24 MPG.
Seems like better mileage than I've heard the Ford/Chevy get...
With what your planning to do, I don't think you wil be towing max loads?
I would think mileage is more important than absolute towing power?

Another Question: Why use CNG?     It's not as readily available on the road as Diesel..



Ride safe, Ted

I will be using diesel, the CNG is injected along with the diesel to provide better economy.  During towing conditions I have heard that some guys are running a 50/50 mix and seeing between 20-25 mpg (including the extra CNG) while towing 10,000 lbs.

[Kazairl]

 Plus Natural gas is very low on energy value so in order to get enough to make any appreciable range out of it you have to compress it to fairly high pressures and then you're carrying around a bomb with you. How is the natural gas injected into the engine?

 Just a bad idea all the way around in my opinion. I'm not going to get into a Ford vs Chevy vs Dodge argument, But it's not uncommon for most of the pre-08 trucks from each manufacturer to get in the high teens low twenties unloaded.

[Jeremy Mitchell]

Plus Natural gas is very low on energy value so in order to get enough to make any appreciable range out of it you have to compress it to fairly high pressures and then you're carrying around a bomb with you. How is the natural gas injected into the engine?

 Just a bad idea all the way around in my opinion. I'm not going to get into a Ford vs Chevy vs Dodge argument, But it's not uncommon for most of the pre-08 trucks from each manufacturer to get in the high teens low twenties unloaded.

It is compressed to 3000-3600 psi but is supposedly just as safe as a tank of diesel.  The advantage is that while supplementing with CNG it can get the same mpg's while towing as an unloaded truck that is just running on straight diesel.

[Son of Pappy]

Just did a quick look around, the 2 biggies that stood out are fuel availability and cost of conversion, coupled with tank purchase, which also limits bed space.
So, VA voc. rehab potential, with corresponding grant?  Sure would help with a new enterprise Jeremy.  Leaving really sucks, eh?  Good luck, I sure as he!! hope all goes well.

[Kazairl]

Yeah right. Should the tank get damaged in some way(like in an accident)3000 psi will make a heck of a boom.

CNG takes also take up a lot of space for the energy potential they contain. Natural gas is very low on energy even compressed to high pressures. You'll also have to think about the availability. Even using a 50/50 mix your still going to run out of CNG before you go through a tank of diesel. Unless there is a CNG fill up at every gas station you visit you're going to go long periods of time  on straight diesel which will increase the miles you will have to drive to actually see any monetary gain from it.

 Then there is the issue of introducing a flammable gas into the air stream. This leads to an uncontrolled timing event because the heat from the high compression will set off the CNG before the diesel fuel is injected(Preignition). This leads to high pressure spikes and in especially damaging in a heavily loaded engine. 

[Cholla]

I don't know why anyone would be concerned about a CNG tank on board a vehicle. 20 gallons of gasoline is much more dangerous IMO.

[Kazairl]

Gasoline doesn't rapidly expand when it is released from its tank.

[Jeremy Mitchell]

Just did a quick look around, the 2 biggies that stood out are fuel availability and cost of conversion, coupled with tank purchase, which also limits bed space.
So, VA voc. rehab potential, with corresponding grant?  Sure would help with a new enterprise Jeremy.  Leaving really sucks, eh?  Good luck, I sure as he!! hope all goes well.

The VA grant seems like a long shot from what I have read so far, I am just hoping for a low interest VA small business loan to get everything started.  Trailers and 1 ton trucks ain't cheap.   

I know the availability is spotty at best in some parts of the US, but if I can store 25-30 gallons of CMG and 34 gallons of diesel that should give me a range of roughly 1200 miles if I can get 20 mpg which is supposedly very easy to do with a 50/50 mix while towing.  1200 miles should be enough to find the next CNG fueling station. 

[Son of Pappy]

Well, if ya ever make a run out this way ya always have a place to park for the evening, plenty of space

[Jeremy Mitchell]

Gasoline doesn't rapidly expand when it is released from its tank.

Your opinion has been noted.  If you had some practical knowledge to offer I would be more than willing to take it under advisement.  But since the EPA, DOT, and CARB have already checked out the system and given their stamps of approval so that has to carry a little bit of weight. 

[Kazairl]

It's your vehicle. You do what you want. I can tell you that your mileage estimates are way too optimistic.

  A tank that has a liquid volume of 30 gallons is only 4 Cubic Feet.  Compressed to 3000 Psi that will give you 820 Standard Cubic Feet of Natural gas. Since Natural gas is around 1000 Btus per SCF that gives you a total of 820000 btus.

Diesel fuel is around 139000 btus per gallon.  820000/139000 = 5.9. Which means that 30 gallon sized tank full of natural gas will hold the energy equivalent of 6 gallons of diesel fuel. At 20 MPG that will buy you 120 miles.  TO get 600 miles out of it you would need a tank that holds 20 cubic feet or 150 gallons.

[Excavator]

I just don't think it would be worth it, the install and rigging would be very complicated (expensive) in my mind just for a supplement. The injectors on this engine are very expensive to replace, as much as 5000.00 at a dealership so I would be afraid to do this to my truck. If I got into transport I would set my pricing according to the cost of diesel fuel.

I have an 09 3500 Duramax/Allison that gets about 16mpg on interstate empty, about 12 loaded. The Cummins is much better on mileage and will run for many many miles but the Dodge truck is not going with it.....I know because I had one for 9 years....never again.

[Cholla]

Gasoline doesn't rapidly expand when it is released from its tank.

Go out to your car and poke a hole in the tank and see how fast the gasoline spreads. Worse, you can't see how much faster the fumes spread. One teaspoon of gas in the bilge of a boat is roughly equivalent to a stick of TNT. The fumes are worse than the liquid.
When is the last time you heard of a CNG powered vehicle exploding? I can't remember any.

[Jeremy Mitchell]

I just don't think it would be worth it, the install and rigging would be very complicated (expensive) in my mind just for a supplement. The injectors on this engine are very expensive to replace, as much as 5000.00 at a dealership so I would be afraid to do this to my truck. If I got into transport I would set my pricing according to the cost of diesel fuel.

I have an 09 3500 Duramax/Allison that gets about 16mpg on interstate empty, about 12 loaded. The Cummins is much better on mileage and will run for many many miles but the Dodge truck is not going with it.....I know because I had one for 9 years....never again.

The way that I understand it there is no CNG going through the injectors, it is fogged (similar to a nitrous system) into the intake before the turbo and cools the intake charge.  Once the diesel is compressed and ignites the CNG will ignite and burn the remainder of the diesel that would normally be wasted.  Obviously I need to do some more research so I am 100% aware of all the benefits and drawbacks.

Your opinion on the Cummins/Ram and Duramax/GM issue is shared by me.  I am also researching medium duty trucks since they would hold up so much better to a life of heavy loads.

[Leo]

Norther Indiana Public Service Company (a natural gas utility) has been running a CNG vehicle fleet since the late 1960's.  It was in the late 1980's the last I was around them, they may still run CNG, but I cannot verify.   They were all gasoline cars and trucks as far as I know.  I never saw a CNG tank on any of their big Diesel trucks.