CNG Powered Cars & Trucks

[Merkava_4]

The main reason I'm attracted to the CNG idea is because of the lack of fumes. There wouldn't be any fumes when I first start the car up in the morning, and once I get on the road, there wouldn't be any fumes coming in through my dash vents from the CNG car in front of me. I absolutely love CNG powered UPS trucks. I can pull bumper to bumper with one and turn my dash fan on high speed and literally breath in a sigh of relief. That UPS truck is burning all its fuel completely and cleanly before it exits the tail pipe.

In stark contrast, my gasoline powered Buick LeSabre belches out noxious fumes for 10 minutes while it's cold until the catalytic converter finally lights off.

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[Barkleymut]

quit tailgaiting and or driving in reverse

 

[Spazdog]

I have a client that has a Chevrolet C10 converted to propane. The exhaust fumes at idle will make your eyes burn. Then again it is a carbureted smog era engine. 8.5:1 Compression ratio and carburetor. Carbonic acid or something from trying to burn a 110 octane fuel in a low compression engine undoubtedly with a smog era cam grind.

 

[Bandito440]

I love the CNG/Propane idea because I could fuel up at home with a home compressor. I don't have CNG service at my house, but I do have a 500 gallon propane tank. It would be nice to fuel up in my garage and have greater control over fuel purchases.

 

[Fleetmon]

We run a fleet of buses that are Cummins 8.3L CNG and they perform flawlessly. 3.1 MPG on average but fuel is only $1.90 per gallon.....compared to our Cummins ISM (11 liters) diesel fleet which averages 3.8 MPG at $3.50 per gallon.

CNG fuel station maintenance is expensive though....we have two compressors with a third as a spare. The maintenance costs, including one full-time employee is around $400k per year.

 

[TiredTrucker]

For those thinking about home filling, I think only the propane idea is economically viable. Personal fill stations using a propane tank already on the property is no where near the type of thing that a CNG compressor would be. I live rural and have propane. Converting my pickup the stuff has crossed my mind a few times.

 

[Fleetmon]

Yep.....^ this. CNG compressors are large and very expensive....our buses fuel to 3600psi.

 

[Cujet]

Natural gas has a much higher octane than gasoline. For sake of discussion, it's about 130. That means the use of CNG in today's engines is likely to be somewhat wasteful of the fuel's potential. Even if your engine has a compression ratio of 11 to 1. In much the same way as E-85 has higher octane than gasoline and high latent heat of vaporization leading to it's ability to operate efficiently in engines with much higher than today's normal CR's.

It seems likely that a properly designed CNG engine will have a CR of about 16 to 1. This presents it's own set of problems. As robust design is required, cylinder head flow must be carefully considered as valves can be shrouded at such CR's and emissions need to be addressed. I think the Honda CNG Civic used nearly a 13 to 1 CR.

A more interesting and efficient alternative might be to use a dual fuel setup such as a turbo diesel engine that ignites the NG via a tiny diesel injection pulse.

 

[SteveSRT8]

Originally Posted By: Merkava_4
The main reason I'm attracted to the CNG idea is because of the lack of fumes. There wouldn't be any fumes when I first start the car up in the morning, and once I get on the road, there wouldn't be any fumes coming in through my dash vents from the CNG car in front of me. I absolutely love CNG powered UPS trucks. I can pull bumper to bumper with one and turn my dash fan on high speed and literally breath in a sigh of relief. That UPS truck is burning all its fuel completely and cleanly before it exits the tail pipe.

In stark contrast, my gasoline powered Buick LeSabre belches out noxious fumes for 10 minutes while it's cold until the catalytic converter finally lights off.


Engines from our fleet in the 70's were the cleanest you have never seen, nearly carbon free inside. Oil stays clean, too. High octane means the timing could be advanced which makes an engine feel sharp and gives good throttle response.

Too bad about that slow cat light off. In a properly running car that process is over before the fast idle slows down!

 

[Jarlaxle]

A problem: CNG is not permitted in some tunnels. (That's why we do not have at least one CNG truck at work.)

 

[Fleetmon]

plus, CNG vehicle shops need expensive modifications, i.e. alarm system, auto fans with auto fresh air, explosion -proof receptacles, etc. The other alternative isshut off the gas system and sniff-test every vehicle before shopping.

Propane vehicles don't need the modifications and they are treated no differently than gasoline-powered.

CNG rises, propane falls.

 

[Garak]

Originally Posted By: Fleetmon
Propane vehicles don't need the modifications and they are treated no differently than gasoline-powered.

We do have some parking garages here that prohibit propane powered vehicles. Of course, beaters with leaking gas tanks aren't a problem.

 

[Fleetmon]

Yeah, I've seen propane restrictions also so I should have worded it that most places treat them no differently than gasoline. I think there's a pretty good misunderstanding between the differences of NG and propane.

Either are good alternatives to gasoline although I feel propane is better suited to low speed operations and NG is limited by the available fueling facilities. We have noticed a fairly large increase in NG vehicles in the past year or so.....it used to be only our buses fueling at our station with an occasional other vehicle but now we get a lot of hotel shuttle vans and food delivery trucks, including tractor trailers, fueling on a regular basis.

Although we own the fueling station, we lease it to a NG provider and they handle the station maintenance and customer billing.

 

[hattaresguy]

I looked at CNG powered pickups but the problem is the tank is in the bed so you lose 2ft of it. Also its a $10k option.

Not worth it yet.

If it was a couple thousand dollars to upgrade and the tank was mounted under the bed where it belongs I'd probably bite. 99% of my driving is around town and natural gas is at about $1.60 a gallon right now. Plus I could refuel it at home.

 

[Fleetmon]

I'm assuming that would be slow-fill? I'm guessing it would still take a home compressor station of some type too? Would you get a full tank?

Most of the small vehicles I see are 3000psi with the larger vehicles at 3600psi.

FWIW, I was approached recently by a salesman that was offering propane conversion kits for Ford-type trucks....F250 and larger and the tank(s) were installed between the frame rails. PM me for the contact info if interested....the kits were very reasonably priced.

The only reason we aren't interested is because we have enough different types of vehicles/fuel as it....gasoline, Avgas, diesel, biodiesel, jet A, kerosene, propane, CNG, and electric.

 

[Fleetmon]

NG should become more popular in the future too.....I just passed a sign at a York Sheetz and they had diesel listed at $4.24 gallon!