Compressed Natural Gas For Vehicles

[two_bit_score]

CNG is a viable alternate for fleet use. Here in California, we are not allowed to procure diesel busses to transport children to school They must be CNG or Propane. About 50% of our fleet is now CNG. There are several advantages. Maintenance on the engines has considerably decreased. When diesel was $4+ per gallon we were making CNG for about $1 per gallon. We saved over $200K just last year on fuel.

The disadvantages are the shorter range and slightly lesser power. We have both slow fill and fast fill capability and the slow fill is a perfect solution for school busses.

Most of our white fleet is also going to CNG. We tried conversions on some of our gas units 4 or 5 years ago and they were less than successful but now every major manufacturer offers CNG as a factory option.

The other advantage is that they are exempt for smog checks.

If you want to see the availability and current cost for CNG in your area, go here.

CNG stations and Prices for the US, Canada and Europe

Great post! CNG is mostly misunderstood. It's the most viable transportation fuel we have in America and it's use should be encouraged for many reasons.
It's cleaner, cheaper and mainly it's plentifully available in America.

We currently import about 70% of the oil we use in America. Most of that is used to produce gasoline or diesel. If we could cut our dependence on foreign oil and kept the money we are sending for oil - $BILLIONS$ per month - at home by using our own domestically produced natural gas as our primary transportation fuel we could easily pull ourselves out of the recession and do a lot to clean our environment at the same time.

 

[jimainiac]

I just heard T. Boone Pickens on NPR, giving a speach on the country's energy problems. He's for converting heavy duty trucks from diesel to natural gas. He told about a city in California that did a study on the sources of air pollution and found that the city's trash trucks were responsible for a lot. They decided to switch to natural gas power for the trash trucks, and have done half of them. I don't think they are converting the trucks, but replacing them with natural gas powered ones.
Apparantly Mr. Pickens thinks natural gas should be used in vehicles now, as a "bridge" fuel, to immediately give the country a domestic alternative to foriegn oil, which he predicts is going to go right back up in price as soon as the U.S. economy recovers. He says, and rightly so, that the way things are now the foriegn oil suppliers have more or less a monopoly with no incentive not to raise prices as much as possible as soon as demand rises again, and introducing natural gas in a big way would give some much needed competition. It sounded like he sees a big future for battery operated vehicles, but that battery technology needs to be very much improved.
Mr. Pickens strikes me as a really level headed, practical guy who has done his homework on this subject. He seems to just want to get the country onto the right track with some practical solutions to the reality that oil is in dwindling supply compared to increasing worldwide demand, and the U.S. has to import almost all that it uses.

 

[tommu56]

hit the web page PickensPlan

I think he is on the level and has a good plan executing it will be the real challenge the oil company's wont embrace adding the equipment to the gasoline stations.

We have about 10 forklifts running on cng at work the engines run clean but they do eat valve seats and they they don't gum up like the propane ones.
the compressor station has 2 high pressure (4500 psi) compressors and 8 high pressure cylinders in 3 staged banks the tanks on the forklifts only fill to 3600 psi ani ti only takes about 2 minuets to fill the trucks if the bank is full.

tom

 

[Redneck in training]

I wouldn't think that propane would be such a good option for motor vehicles on the roads. I thought the advantage of propane, for forklifts and such, was that it was safer to run them indoors.
I wonder if that conversion option that Ford offers would be for propane or natural gas? $6000. sounds like a lot. I wonder how extensive the conversion is?

Propane has about the same energy density as well as energy content as gasoline. Therefore a vehicle would have about the same mpg and no loss of power. But it isn't substitute for oil based fuels such as diesel or gasoline because it si also made from oil.
CNG is completely different. It has about the same energy density only in liquid state (LNG) that is achieved at very low temperature. LNG is typically stored at -162C or -260F at about 2 psig pressure (it shrinks about 600 times). Not too practical for vehicles. In its compressed form it has much smaller energy density so the vehicle needs either large tank or has smaller reach.
Energy density is kJ or BTU per volume.
Energy content is kJ or BTU per mass.

 

[Builder]

I live 1 mile from a medium sized university.

All of its' maintenance vehicles (mostly GMC Sierra 4x4 3/4 & 1-tons) run on CNG.

They seem to get the job done just fine.

 

[Bird]

Propane has about the same energy density as well as energy content as gasoline. Therefore a vehicle would have about the same mpg and no loss of power.

I certainly do NOT have the technical knowledge to agree or disagree with that statement, but I know in the RV business (several years ago) they claimed that a gasoline powered generator, when converted to LPG, would loose 11% of it's gasoline powered output. I had a 4.5 KW Kohler generator with that conversion so that supposedly made it just a bit over 4 KW output but I never had a way to actually measure it. I just know it provided all the power I needed for our fifth-wheel.

 

[Diamondpilot]

You are right Bird as far as the generators go. I have a home stand by generator and I have it set up to run off Gasoline but it can be converted to propane but it looses about 15% of its rated output if you do so.

Chris

 

[Bird]

Chris, if that's true of the generators, would that mean less power for a car or truck converted from gasoline to LPG or not?

 

[Redneck in training]

Propane has about the same energy density as well as energy content as gasoline. Therefore a vehicle would have about the same mpg and no loss of power. But it isn't substitute for oil based fuels such as diesel or gasoline because it si also made from oil.
CNG is completely different. It has about the same energy density only in liquid state (LNG) that is achieved at very low temperature. LNG is typically stored at -162C or -260F at about 2 psig pressure (it shrinks about 600 times). Not too practical for vehicles. In its compressed form it has much smaller energy density so the vehicle needs either large tank or has smaller reach.
Energy density is kJ or BTU per volume.
Energy content is kJ or BTU per mass.

I need to make a correction to above statements.
1 gal of propane (LPG) has 91600 BTU
1 gal of gasoline has 125000 BTU
1 gal of ethanol has 76000 BTU
1 cuft of NG has 1030 BTU
1 cuft of propane gas has 2500 BTU


Engine powered by LPG would have the same power as gasoline but with about 30% higher fuel consumption. The problem is that the LPG is delivered as gas (that has many times larger volume than gasoline that is delivered as liquid mist) displacing some of the air sucked to the engine. It has similar effect as partialy closed throttle. If the LPG would be injected then the engine could have about the same power.
Engine powered by ethanol would have about double of fuel consumption than powered by gasoline.

 

[Diamondpilot]

Chris, if that's true of the generators, would that mean less power for a car or truck converted from gasoline to LPG or not?

Like the other guy said, to make the same HP you would need more fuel. On my generator and other like engines me and you have seen this is not cost feasible so the only option is a loss of power. No free lunch.

Chris