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burntpuppy
User Rank
Silver
Re: CNG / Propane / Gasoline
burntpuppy   5/29/2012 11:24:39 AM
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The horsepower was a bit lower than the gasoline 318s of the day, but the torque was bigger. The taxi I drove got refueled once per 12 hour shift, versus 2 or 3 times for the same car with a gasoline engine.

 With the high compression allowed due to the octane of propane the torque was great then the gas engines. They were a pleasure to drive. One the highway ( I did a few trips to Toronto, and one to Windsor) there was no issue with getting fuel.

 We refueled at Superior Propane, or at a station in the west end.

 As far as the oil, we stretched the change interval to 15,000km and had great engine life. The only car that died while I drove was due to the drivers never checking the oil.

GlennA
User Rank
Gold
Re: CNG / Propane / Gasoline
GlennA   5/29/2012 10:54:11 AM
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burntpuppy;  318 cid is about 5.2 liter.  150 hp from a 5.2 is not a lot of power.  The 5.7 liter Hemi V8 is rated at about 380 hp.  For a taxi fleet they would have a central filling station, and mostly short trips meant a small reduction in range could be managed.  There are niche applications where propane would be a good fit.  Propane does burn cleaner, and doesn't dilute the engine oil like gasoline does.  But propane doesn't 'replace' the 'light ends' - the engine oil looks clean, but eventually behaves like 90 weight.

burntpuppy
User Rank
Silver
Re: CNG / Propane / Gasoline
burntpuppy   5/29/2012 10:05:33 AM
NO RATINGS
Propane also has a very high octane rating. In the early 80's Chrysler sold propane powered caravelles. These cars were designed for fleet use ( Amherst Taxi in Kingston had a few dozen). 318 cubic inch engines with 16:1 compression, 150 horsepower, lots of torque and long life. The nicest thing about them is that they warmed up very fast, nice when winters went to -35C.

At the same time there were a few natural gas cars, they SUCKED, less power, and very heavy tanks that needed to be filled several times in a shift.

ChasChas
User Rank
Platinum
Re: Scary fuel choice
ChasChas   5/29/2012 10:02:18 AM
NO RATINGS
 

I agree naperlou, design can cover a multitude of sins. Double walls, and perhaps the air bag sensor would trigger the auto shutoffs for examples. I think it can be done as safe as gas.

No car yet can survive a hard collision without fire.

GlennA
User Rank
Gold
CNG / Propane / Gasoline
GlennA   5/29/2012 9:52:48 AM
NO RATINGS
There are a lot of misconceptions in this.

Propane is stored in tanks pressurized to about 200 psi.  When propane was used as a motor fuel years ago, a 'liquid' tank was used.  This draws liquid propane from the bottom of the tank, to a vaporizer and then to a carburetor.  A barbecue tank is a vapor tank.  The heat to vaporize the propane comes from the surrounding air.  That is why the tank feels cold in use, and may even have frost on the sides.  The energy density of propane is less than that of gasoline.  Natural gas has less energy density than propane.  A propane converted engine had a 'cold' intake manifold.  A carbureted gasoline engine had a 'hot' intake manifold to assist is vaporizing the gasoline.  Cold propane is denser, giving more power than hot propane.  An engine that is dual-fuel - propane or gasoline, will run poorly on either.  Compressed natural gas is used because of the high pressures required for liquified natural gas.  Natural gas vapors are lighter than air,  Propane and gasoline vapors are heavier than air.

I don't know how propane or natural gas are being developed for integration into fuel injected engines.  Someone who knows diesel fuel injector systems may know if the propane could be circulated to be sure liquid propane is at the injector instead of vaporized propane.

Compressed natural gas and propane and gasoline are all hydrocarbons = fossil fuels.  Converting to propane or natural gas just shifts the load to a different flavor of fossil fuel.  Is anyone familiar with any plans to add butane to the mix also ?

naperlou
User Rank
Blogger
Re: Scary fuel choice
naperlou   5/29/2012 9:45:57 AM
NO RATINGS
Beth, I understand your concern, but gasoline was a dangerous fuel not so long ago.  Remember the burning compact cars of the 70s?  I think that the answer lies in design. 

In many parts of the world natural gas is used extensively.  I would not be terriably concerned about the tanks.  I had a business where we had an opportunity to see what would happen if you fired a gun at a propane tank.  It did go up, but only with a very well placed shot.  I don't know what the actual statistics are from this, but I expect that there are ways to make it safe.  I also noticed that there are a number of trucking firms going to this fuel, so we will see it more often. 

gsmith120
User Rank
Platinum
Re: Scary fuel choice
gsmith120   5/27/2012 5:51:29 PM
NO RATINGS
Beth, I agree with you on the fuel issue.  Seems to me I remember a Fiat car when I was a child or maybe I'm wrong. Almost every day I see one of these little cars. Kind of cute but don't think I will be buying one any time soon.

Jack Rupert, PE
User Rank
Platinum
Re: Scary fuel choice
Jack Rupert, PE   5/27/2012 5:07:30 PM
NO RATINGS
The question that it also brings is how do you ensure safety after the car has been around the block for a number of years.  Are people really going to do the necessary maintence to ensure structural integrity of the tank.  I'm thinking, for example, of a bicycle helmet.  If it has been used to save your skull, you discard it and buy a new one even if it "looks" OK.  A minor fender bender might require a bit more investigation with a high pressure, highly flammable gas.

Also, I could be wrong on this point, but isn't propane heavier than air?  Seems that a leak would be more dangerous up front than gasoline, since the vapor (i.e., the flammable part) does seem to dissappate rather quickly.

jmiller
User Rank
Platinum
Re: Scary fuel choice
jmiller   5/27/2012 9:41:42 AM
NO RATINGS
I agree there is a need to educate.  I too get a little nervous putting a tank in the trunk.  I consider myself lucky that I have a pickup truck to go get gas for the lawn mower.  But I'm guessing that someone has done a ton of research to insure cars running of natural gas are as safe as any current vehicle.  I know forklifts have been running on this stuff for years. 

I also like the idea of several different alternative fuels/concepts being developed at the same time. 

jmiller
User Rank
Platinum
Re: Under Pressure
jmiller   5/27/2012 9:38:02 AM
NO RATINGS
I wonder what the range is on a small tank that attaches to my grill.  The interesting part of moving to a technology like this, is there are already places to go and get this fuel.  One has only to go to the local hardware store or in some cases where I live, the local gas stations already carry these little tanks.

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