Mark,
What was your experience driving under propane vs gasoline?
The onlly propane powered rigs I've driven had forks on the front!
Larry Davick
The Mystery Machine
ljdavick wrote on Fri, 11 December 2009 15:09
> Mark,
>
> What was your experience driving under propane vs gasoline?
>
> The only propane powered rigs I've driven had forks on the front!
>
> Larry Davick
> The Mystery Machine
Larry,
I'm not Mark (you may have guessed), but I have some interesting experience in this venue.
At the same time we (at a contract development lab in Ann Arbor) were building the multi-fuel -OH capable vehicles, we were also contracted to develop and build two dual fuel -LPG vehicles. These were based on a GM platform with a turbo-charged V6. One was a closed loop Impco adapted to the existing throttle body. the other did a step-over conversion to liquid propane at the port injectors.
Both vehicles were scary fast, but the liquid injector had the propensity to be terrifying.
Both would start just fine, but had performance issues when running dead cold (DUH!). Even though the ECU could control maximum boost optimize the spark advance based on a very functional knock detector (slight bow here), the programing had trouble when cold and in the open loop mode until we were just about done with the program.
With the Impco, the problem was withdrawal rate cold. The vapor fuel system had to draw gas of the tank to start and only when the jacket water temperature gets hot enough, can it change over to using the liquid withdrawal system and the vaporizer to feed the engine. This is a good plan unless the cold operation has caused the tank to sub-cool so much that the tank pressure is too low to deliver the liquid to the vaporizer. Then you sit by the side of the road and when you can get it to start you nurse it off to someplace you can warm it up.
The port inject vehicle had its own quirk. You can just imagine the chill of the liquid propane flashing to gas when the injectors were open. This caused a charge air cooling that a sometimes could make the charge in the cold cylinder virtually fire-proof. As above, this also could be worked around with just a little of the patience so rare in young gear-head engineers. NOW, When this vehicle was up to operating temperature, that chilling would cause a charge density increase that allowed it to produce enough horsepower to destroy the first two transmissions.
All the vehicle fuel tanks used were ASTM code and designed for over the road vehicle use and fabricated for us with slosh baffles and an array or fitting not normally found in LP fuel tanks.
There is, in just my humble but experienced opinion) no disadvantage to propane as a vehicle fuel other than the required weight of the fuel tank.
Ah, Memories of spending other peoples money and getting paid to do it. Almost makes me wish I was a Congressman.
Matt
--
Matt & Mary Colie
'73 Glacier 23 Chaumiere (say show-me-air)
SE Michigan
I found a misconception in some of the literature, including a blurb in the Wickepedia. The statement has been made that propane produces less power because of the lower heating value, which is about 20% less than gasoline on a per gallon basis. That doesn't make sense as one merely has to feed in more propane. The real reason is that propane has a molecular weight of about half gasoline and therefore in the gaseous state it takes up more of the volume. To make matters worse, the heat to vaporize gasoline is largely taken from the incoming air, cooling it in the process and increasing the density of the charge. Propane is usually introduced as a gas, so it doesn't cool the charge. Except in the case that Matt described where liquid is injected.
I'm afraid most of these interesting alternative fuels don't fit the GMC operating profile very well. Propane is probably just as expensive or more than gasoline. CNG provides such a low range that it wouldn't be of interest for a vehicle that specializes in taking trips. LNG could provide the range, but there are virtually no refueling stations around.
Gary
________________________________
From: Larry Davick <ljda...@comcast.net>
To: gmc...@temp.gmcnet.org
Sent: Fri, December 11, 2009 7:10:04 PM
Larry,
__________________________________________________
Do You Yahoo!?
Tired of spam? Yahoo! Mail has the best spam protection around
http://mail.yahoo.com
Even CNG stations are hard for find. There are only two in my county and both are only open day shift Monday thru Friday. They are run by the local gas company's and primarily refuel gas company CNG vehicles. The gas company is abandoning CNG vehicles so their two stations may soon disappear all across the state.
--
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
--
Steve Ferguson
'76 EII
Sierra Vista, AZ
Urethane bushing source
www.bdub.net/ferguson/
Both vehicles were scary fast, but the liquid injector had the propensity to be terrifying.
_____________________________________________________________
Does the propane have to feed by liquid to develope the power to the engine?
I had wondered if a line could be used from the on board propane tank for emergency use, ie you run out of gas or supplement the gasoline system?????
Even if you had to limp down the road, you'd still be moving.
LarC ( Once again pretending to be an engineer, only I don't have a train. )
--
Gatsbys' CRUISER :d
74 GLACIER X, 260
455/APC/4 bagg'r(ver3)
Remflex Manifold gaskets
_______________________________________________
Purchased 08-18-04
_
J.R. Wright
>
>
> Both vehicles were scary fast, but the liquid injector had the
> propensity to be terrifying.
> _____________________________________________________________
>
> Does the propane have to feed by liquid to develop the power to the
> engine?
>
> I had wondered if a line could be used from the on board propane
> tank for emergency use, ie you run out of gas or supplement the
> gasoline system?????
>
> Even if you had to limp down the road, you'd still be moving.
>
>
> LarC ( Once again pretending to be an engineer, only I don't have a
> train. )
>
_______________________________________________
On the 455 GMC trucks that I had, the propane was heated by the heater hoses. It was kept warm all the time. Except for start up. Propane will not start at minus 40 as I found out while up north.
--
"I've always been crazy, but it kept me from going insane"
Larry C wrote on Sat, 12 December 2009 13:34
> Does the propane have to feed by liquid to develop the power to the engine?
>
> I had wondered if a line could be used from the on board propane tank for emergency use, ie you run out of gas or supplement the gasoline system?????
>
> Even if you had to limp down the road, you'd still be moving.
>
> LarC ( Once again pretending to be an engineer, only I don't have a train. )
Larry,
The simple answers are No and No.
A typical LPG fuel system uses a vaporized fuel feed to the metering device (it is nothing like any carburetor your know).
When a dual fuel is assembled, there is a gasoline fuel system and an LPG fuel system that are simply both connected to the same engine.
If you were to try to run the coach on the existing LP tank, you could suck that babe dry in relatively short order. The installation would be a lot to drag around for small gain.
The Impco used on a 455 size engine would add about 4" to the height (iirc), and no sane human should pursue the liquid injector bit. The description in the prior post was a vast simplification.
Matt
--
Matt & Mary Colie
'73 Glacier 23 Chaumiere (say show-me-air)
SE Michigan
--- On Sat, 12/12/09, Matt Colie <mco...@chartermi.net> wrote:
Larry C wrote on Sat, 12 December 2009 13:34
> Does the propane have to feed by liquid to develop the power to the engine?
> Yes the tank would have to changed to 1 with a bottom valve for liquid.
> I had wondered if a line could be used from the on board propane tank for emergency use, ie you run out of gas or supplement the gasoline system?????
> you wouldn't have enough vapour for more than an idle.
> Even if you had to limp down the road, you'd still be moving.
>
> LarC ( Once again pretending to be an engineer, only I don't have a train.. )
________________________________
From: Larry <slawre...@yahoo.com>
To: gmc...@temp.gmcnet.org
Sent: Sat, December 12, 2009 11:34:53 AM
Subject: Re: [GMCnet] Propane Power
Both vehicles were scary fast, but the liquid injector had the propensity to be terrifying.
Ljdavick at comcast.net
I'm not an engineer, but I did own a 1976 Ford Van that I had converted to Propane in the early 80's.
The Provincial Govn't at the time (81 or 82) brought out a program to convert commercial vehicles to alternate fuels. They were not taxing propane at the same rates as gasoline and still are not here, propane is about 1/2 the price of gas.
The system had to be single fuel for the Govn't rebate. Liquid came from the tank to a vaporizer which used engine coolant. From there it went to a propane throttle body. The system I remember was Impco.
It was installed by one of the Govn't approved conversion places. On the way home it ran like a dog. If I remember I could not get it much over 50mph.. and 40-45 was more typical.
I took it back several times with no real improvement.
Then I heard of a local mechanic who would make it run. From what I remember he just "recurved" the distributor advance. After that it was driveable, but it certainly never had the power on Propane that it had on Gas. And the mileage dropped if I recall about 20-25%
The BIG BENEFIT... that engine was a DOG, typical of the era. After switching to propane I put another 100K on it without a repair.
Just from my experience, I don't think the 455 would have enough power on propane to be a pleasant driving experience.
However now I imagine electronic controls have been applied to the Propane conversions and they are much better.
At one point around here there was a significant number of vehicles on propane (taxis, delivery vans, contractor's pickups) however I think they have dwindled to near zero now. But 3 of the 7 gas stations in my town can pump vehicle propane by the litre.
--
Bruce Hislop,
S. Ontario Canada
77PB, 455
http://www.gmcmhphotos.com/photos/showgallery.php?cat=500&ppuser=1906
Norm
RF_Burns wrote on Sun, 13 December 2009 05:10
> I'm not an engineer, but I did own a 1976 Ford Van that I had converted to Propane in the early 80's.
> The Provincial Govn't at the time (81 or 82) brought out a program to convert commercial vehicles to alternate fuels. They were not taxing propane at the same rates as gasoline and still are not here, propane is about 1/2 the price of gas.
> The system had to be single fuel for the Govn't rebate. Liquid came from the tank to a vaporizer which used engine coolant. From there it went to a propane throttle body. The system I remember was Impco.
> It was installed by one of the Govn't approved conversion places. On the way home it ran like a dog. If I remember I could not get it much over 50mph.. and 40-45 was more typical.
> I took it back several times with no real improvement.
>
> Then I heard of a local mechanic who would make it run. From what I remember he just "recurved" the distributor advance. After that it was driveable, but it certainly never had the power on Propane that it had on Gas. And the mileage dropped if I recall about 20-25%
>
> The BIG BENEFIT... that engine was a DOG, typical of the era. After switching to propane I put another 100K on it without a repair.
>
> Just from my experience, I don't think the 455 would have enough power on propane to be a pleasant driving experience.
>
> However now I imagine electronic controls have been applied to the Propane conversions and they are much better.
>
> At one point around here there was a significant number of vehicles on propane (taxis, delivery vans, contractor's pickups) however I think they have dwindled to near zero now. But 3 of the 7 gas stations in my town can pump vehicle propane by the litre.
Bruce,
To clear this situation up, let me assure that the loss of performance you saw was not the result of the conversion to LPG fuel. The increase in fuel rate (reduced fuel economy) is a given, but if the Impco was properly installed and the engine was recalibrated for propane that change should be more like 15%. This is assuming that there are no changes in use or driving style.
The funny story here is that a fleet conversion that we were a party to saw a 20~25% increase in fuel consumption in the converted vehicles. We couldn't explain it. We put "flight recorders with many inputs in some of the fleet.
The data was interesting. The LPG vehicles were always the first out by driver choice, and the area under the road speed curve was just about the same (they traveled similar distances), but the average speed was significantly higher. When drivers were queried, it turned out that the LPG vehicles were much more fun to drive.
--
Matt & Mary Colie
'73 Glacier 23 Chaumiere (say show-me-air)
SE Michigan
...and if we wrap the air conditioning condensor around that propane
tank we could freeze beef going up the Grapevine in August!
Ljdavick at comcast.net
_____________________________________________________________
:lol: LOL :lol:
LarC ( I knew there had to be an UP side )
Oh most definitely it started right up and ran much smoother on propane. Like I said the engine was a dog before. It was a Foed E100 Econoline van with a 351 engine. I never bothered to bolt the dog house down since it would be off several times a month and in the shop at least once a month.
As far as getup and go though, it just felt like I was pulling a heavy trailer behind me. I have no doubt it could have been better tuned, however my clients had similar experiences on their vehicles.
Interestingly though, Propane today is 58.9 cents/litre verses gas at 95.9 cents, I don't know of a single commercial client of mine that is using it.
--
Bruce Hislop,
S. Ontario Canada
77PB, 455
http://www.gmcmhphotos.com/photos/showgallery.php?cat=500&ppuser=1906
_______________________________________________
Two big cylinders on the roof - uh - oh - middle age spread.
Better to spend the money on paint.
Larry Davick
The Mystery Machine
The things I don't like are the rubber roof and the floor plan. It
looks like those extra 6' are used up in a larger bathroom and space
around the rear bed. Not enough compelling for me.
All in all it's a good looking coach.
Larry Davick
The Mystery Machine
With my 454 trucks, I got 10 - 12 MPG with a 2,000 lb camper on.
That was with regular gas or propane. Uphill and down.
--
"I've always been crazy, but it kept me from going insane"
Over here in Holland the price of LPG is half of gasoline, therefore it pays off to have a dual fuel setup. In my coach the tanks are located inside with almost no real burden, two tanks of 100 liter each, with a mileage of 1 in 3 it can take us 600 kilometers.
I like the LPG as it keeps the engine clean, cannot tell you if there is powerloss as I haven't fixed the delivery of gasoline yet, but the coach has enormous power. The system I use is an IMPCO installation with an evaporator attached to the coolingcircuit of the engine, no problems starting in wintertime.
http://www.gmcmhphotos.com/photos/showphoto.php?photo=25712&ppuser=1827&sl=r
--
GMC 230 Painted Desert '73
Chevrolet C-10 stepside '65
Chrysler PT Cruiser 2001 ltd edition
Güldner ADN '57
________________________________
From: Roel <roel.b...@kpnplanet.nl>
To: gmc...@temp.gmcnet.org
Sent: Tue, December 15, 2009 3:27:40 AM
Subject: Re: [GMCnet] Propane Power
Over here in Holland the price of LPG is half of gasoline, therefore it pays off to have a dual fuel setup. In my coach the tanks are located inside with almost no real burden, two tanks of 100 liter each, with a mileage of 1 in 3 it can take us 600 kilometers.
________________________________
From: Norm Bowker <bow...@rogers.com>
To: gmc...@temp.gmcnet.org
Sent: Tue, December 15, 2009 5:56:23 AM
Subject: Re: [GMCnet] Propane Power
Here in Canada the closet tank wouldn't pass inspection as they must be sealed from the interior & vented to the outside.
The tanks are connected to eachother and filled from the outside where the citywater hookup was, the tanks itself are not vented like the propane tank for the furniture is, if the pressure should get too high it is vented through a safetyvalve on the outside. The inside is all protected as the hoses are replaced regularly. Actually it is safer to drive on LPG as it is with gasoline, these tanks are almost indestructable and if they fall over there won't be any spilling, in fact gasoline is much more dangerous when spilled or in case of an accident.
________________________________
From: Roel <roel.b...@kpnplanet.nl>
To: gmc...@temp.gmcnet.org
Sent: Tue, December 15, 2009 12:29:35 PM
Subject: Re: [GMCnet] Propane Power
The tanks are connected to eachother and filled from the outside where the citywater hookup was, the tanks itself are not vented like the propane tank for the furniture is, if the pressure should get too high it is vented through a safetyvalve on the outside. The inside is all protected as the hoses are replaced regularly. Actually it is safer to drive on LPG as it is with gasoline, these tanks are almost indestructable and if they fall over there won't be any spilling, in fact gasoline is much more dangerous when spilled or in case of an accident.
I wonder how all that weight back behind the rear wheels would effect the handling. I also wonder how big a fuel cell would be needed to replace the Onan. The water from the fuel cell could fill the fresh water tank, and the chill off of the propane tanks could augment the A/C.
Dream on...
Larry Davick
The Mystery Machine
----- Original Message -----
From: "Roel" <roel.b...@kpnplanet.nl>
To: gmc...@temp.gmcnet.org
Sent: Tuesday, December 15, 2009 11:29:35 AM GMT -08:00 US/Canada Pacific
Subject: Re: [GMCnet] Propane Power
In New South Wales converting or adding Autogas capability to a road vehicle
MUST be done by a shop that holds a license from the NSW Roads and Traffic
Authority to do so. The installation must be inspected and certified by a
shop that holds a license from the NSW RTA as part of the yearly license
plate renewal process.
The good news is I have a mate that has a license and he's going to show me
what / how to do it so I can do all the work and he'll inspect it.
The tanks must be sealed off from the passenger compartment. I've noticed
when I take taxis to the airport that they have the tank located in the
trunk up against the rear seat. I haven't looked closely and don't know if
it's just the seat that separates the tank from the passenger compartment or
if there is a solid sheet of metal between them. Also I don't know if / how
they vent the trunk.
Regards,
Rob Mueller
Sydney, Australia
AUS '75 Avion-The Blue Streak TZE365V100428
USA '75 Avion-Double Trouble TZE365V100426
-----Original Message-----
From: gmclist...@temp.gmcnet.org
[mailto:gmclist...@temp.gmcnet.org] On Behalf Of Gary Casey
Sent: Wednesday, 16 December 2009 6:41 AM
To: gmc...@temp.gmcnet.org
Subject: Re: [GMCnet] Propane Power
Roel,
Your probably right, but that doesn't change the legal requirements :-(
Gary
Larry Davick
The Mystery Machine
----- Original Message -----
From: "Gary Casey" <casey...@yahoo.com>
To: gmc...@temp.gmcnet.org