Jump to content


Photo

Gas engine future


  • Please log in to reply
62 replies to this topic

#1 cheapracer

cheapracer
  • Member

  • 10,388 posts
  • Joined: May 07

Posted 22 March 2012 - 02:05

When I was working on an exploratory rig taking core samples from coal seams looking for gas (back of NSW, Oz), we were constantly told that the search was on in earnest because gas was the next big thing.

I just noticed this article about Cummins releasing a gas powered (spark ignition), medium duty, highway truck engine, so you have to guess that for someone as big as Cummins to invest in it they may well have information that this is a direction we are headed in the near future?

http://www.ttnews.co...With-New-Engine

http://www.cummins.c...s... 11:10:00.0

Edited by cheapracer, 22 March 2012 - 09:16.


Advertisement

#2 Kelpiecross

Kelpiecross
  • Member

  • 832 posts
  • Joined: October 10

Posted 22 March 2012 - 03:09

[quote name='cheapracer' date='Mar 22 2012, 13:05' post='5611656']
When I was working on an exploratory rig taking core samples from coal seams looking for gas (back of NSW, Oz) we were constantly told that the serach was on because gas was the next big thing. I just noticed this article about Cummins releasing a gas powered (spark ignition) medium duty highway truck engine so you have to guess that for them to invest in the area they may well have information as well and that this is one direction we are headed in the near future?

I suspect gas is "the next big thing" in its use in thermal power stations. I think its problems in storage (in the fuel tanks on a truck and at refuelling stations) would restrict its use. Possibly in the near future it can be converted to a more-useful liquid fuel form.

#3 Greg Locock

Greg Locock
  • Member

  • 4,477 posts
  • Joined: March 03

Posted 22 March 2012 - 04:20

The refuelling problems don't seem insurmountable to me. It'd be a shame to see this resource 'wasted' in power stations, when it is a pretty good transportation fuel, by and large.

#4 johnny yuma

johnny yuma
  • Member

  • 928 posts
  • Joined: May 07

Posted 22 March 2012 - 05:36

At 160 million metric tonnes in 2007 it's already a pretty big thing.Australia's huge North West Shelf produced 16.3 mmt in 2009.Bulk users in public transport or industry are in a better position to use it of course,until the very real storage,transport and refuelling issues are resolved.Some states of the USA have no public outlets at all.

#5 Catalina Park

Catalina Park
  • Member

  • 5,668 posts
  • Joined: July 01

Posted 22 March 2012 - 06:30

My company has had a test fleet of Cummins gas powered concrete trucks for about 5 years now.


#6 cheapracer

cheapracer
  • Member

  • 10,388 posts
  • Joined: May 07

Posted 22 March 2012 - 09:18

My company has had a test fleet of Cummins gas powered concrete trucks for about 5 years now.


You don't happen to drive a VW Combi by the way Cat Park?

Posted Image

Edited by cheapracer, 22 March 2012 - 09:18.


#7 Lee Nicolle

Lee Nicolle
  • Member

  • 5,659 posts
  • Joined: July 08

Posted 22 March 2012 - 09:35

It does make sense as a stationary engine. Gas in all forms seems to vary heaps so I dont know how they are going to allow for that.
Michael, how does the Agitator trucks like it? I guess they are still compression ignition?
We have a few buses here in Adelaide on natural gas too. Last one I saw was on tow!!

#8 Catalina Park

Catalina Park
  • Member

  • 5,668 posts
  • Joined: July 01

Posted 22 March 2012 - 10:02

They are spark ignition. From what I understand they have been a bit of a flop. The gas tanks have to be huge because natural gas does not compress like LP gas. So the bigger tanks cut into the payload. I don't know much about them, it is a different part of the company.

Sydney got a bunch of gas powered buses, they fitted the gas tanks on the roof under a false roof. Then they discovered that they needed to strengthen the roof structure to carry the extra weight. Then with the extra weight they found that they couldn't carry as many passengers without overloading...

#9 cheapracer

cheapracer
  • Member

  • 10,388 posts
  • Joined: May 07

Posted 22 March 2012 - 10:13

Then with the extra weight they found that they couldn't carry as many passengers without overloading...


Australia has gone soft since I left ..

Posted Image

Posted Image

Edited by cheapracer, 22 March 2012 - 10:16.


#10 Catalina Park

Catalina Park
  • Member

  • 5,668 posts
  • Joined: July 01

Posted 22 March 2012 - 10:48

Australia has gone soft since I left ..

Posted Image

Posted Image

They still overload, the government just wrote themselves an exemption to make overloading legal.

#11 GreenMachine

GreenMachine
  • Member

  • 760 posts
  • Joined: March 04

Posted 22 March 2012 - 11:09

I think that we need to be fairly careful about exactly what sort of gas we are talking about. LPG, CNG, and now (compressed? liquefied?) CSG, as I understand it they all have different characteristics.

LPG may be considered something of a marketing success, given its acceptability to high mileage users (in part at least due to excise concessions) and the fairly comprehensive distribution network now in place. I also have seen CNG buses operating here, and if I am not mistaken, the distributor also has some of its vehicle fleet converted to CNG. The fact that there appears to have been no real effort to market CNG more broadly suggests that there are economic or other reasons which would make it unattractive in the marketplace. CP's comments about his company's experiment with CNG tend to corroborate this, and although I have not been able to find any sources, I seem to recall reading something about the relatively low energy content of CNG (perhaps because it is merely compressed, rather than liquefied?).

I suspect that Lee has hit the nail on the head - CNG, and perhaps CSG, will work well for fixed installations, but we will need something else for vehicles.

The Cummins PR suggests that their proposal is very much about a new generation of engines, which isn't going to help fuel the present fleet.

#12 saudoso

saudoso
  • Member

  • 4,577 posts
  • Joined: March 04

Posted 22 March 2012 - 11:19

It's widely used around here (natural gas), mostly converts. Since they where flex to start with they are now Gasoline/Gas/Ethanol. In some cities the majority of cabs runs on gas, with the big pink canisters taking the trunk. You've to let the cab dispatcher know that you have luggage on your way to the airport.

I guess once a year a refueling station goes bang:

Edited by saudoso, 22 March 2012 - 11:19.


#13 cheapracer

cheapracer
  • Member

  • 10,388 posts
  • Joined: May 07

Posted 22 March 2012 - 11:51

It's widely used around here (natural gas), mostly converts.


Sure and I've mentioned that many of China's bus, taxi and many small commercials use CNC but what's interesting here is it's Cummins and they are aiming at mainstream American heavy trucking (and apparently Australia).


#14 John Brundage

John Brundage
  • Member

  • 288 posts
  • Joined: July 08

Posted 22 March 2012 - 16:48

Boston, MA. has about 300 buses equipped with the Cummins 8.3C- gas plus engine. They also have other buses running Detroit series 50G and series 60G engines. This is in addition to their diesel fleet.

Edited by John Brundage, 22 March 2012 - 16:51.


#15 mariner

mariner
  • Member

  • 1,358 posts
  • Joined: January 07

Posted 22 March 2012 - 17:34

I believe that Los Angeles has converted its entire bus fleet to gas ( CNG?) as part of the endless Californian drive to lower pollutants.

As is probably well known shale gas is transforming the US energy scene. Coal shipments to Power plants are falling as gas powered turbine generation is much lower on CO2 and the capital cost is attractive. Unlike Europe which is heavily dependent on Russian gas the USA is seeing some of the lowest gas prices in years due to the success of shale gas drilling.

In such a situation much bigger use of gas in trucks seems highly likely due to economics let alone the " energy independence " political arguments.

Presumably the on board storage problems have been largely solved for big vehicles by buses , leaving only the distribution to fuelling site problems to be solved.

#16 cheapracer

cheapracer
  • Member

  • 10,388 posts
  • Joined: May 07

Posted 22 March 2012 - 17:53

Gas (as in gas not petrol because petrol isn't a gas you stupid Americans, it's a liquid) used to be really cheap in Oz then it got popular for cars and guess what happened ... dribble like below ...

Australian LPG prices reflect the fact that LPG is an internationally traded commodity and influenced by international prices. The international benchmark for the cost of Australian LPG is the Saudi Aramco Contract Price, also commonly called the Saudi CP. The Saudi CP is expressed in US dollars per tonne. As the international price is in US dollars, the Australian dollar exchange rate also affects the Australian price of LPG.

This is the same for all internationally traded commodities. Agricultural and natural resource products are similar to LPG, in that they are subject to the prevailing price in international commodity markets. Australia does not have an influence on LPG price benchmarks, as our production of LPG is small compared to worldwide production. The same is true for the Australian pricing of crude oil and refined products, which are also linked to international prices.


The thing is that Oz has massive gas reserves and daily excess and we not only export about 40% of it, we burn about 20% of it daily. The "International market equality" bullshit gets a bit hard to take. Saudi pulls their own fuel out of the ground so why are they 12 cents per litre, they're on the same International market ...

So America, take on the gas engines and it will just end up status quo - down down, deeper and down.

#17 Bob Riebe

Bob Riebe
  • Member

  • 1,670 posts
  • Joined: January 05

Posted 22 March 2012 - 19:09

Gas (as in gas not petrol because petrol isn't a gas you stupid Americans, it's a liquid)


You ignorant foreign twit,---------- gas- is short for gasoline which is--- Gasoline is a transparent petroleum-derived liquid that is primarily used as a fuel in internal combustion engines --- whereas you twits say petrol which is short for--- Petroleum or crude oil is a naturally occurring, flammable liquid consisting of a complex mixture of hydrocarbons of various molecular weights and other liquid organic compounds, that are found in geologic formations beneath the Earth's surface.--- which is not used for fuel in spark ignition engines.

Have a nice day. :love:



#18 carlt

carlt
  • Member

  • 1,043 posts
  • Joined: June 09

Posted 22 March 2012 - 20:21

Thought you were on a 24G rant with the 'Gas Engine Future' thread title :drunk:

Wondered if Bob Riebe would have a heart attack and think you had turned Commie

Then I remembered you were a member of the commonwealth and not a 'stupid Yank'

petroleum spirit is really quite combustible
http://www.thefreedi...etroleum spirit

#19 Bob Riebe

Bob Riebe
  • Member

  • 1,670 posts
  • Joined: January 05

Posted 22 March 2012 - 21:49

Thought you were on a 24G rant with the 'Gas Engine Future' thread title :drunk:

Wondered if Bob Riebe would have a heart attack and think you had turned Commie

Then I remembered you were a member of the commonwealth and not a 'stupid Yank'

petroleum spirit is really quite combustible
http://www.thefreedi...etroleum spirit

So is gasoline.

Advertisement

#20 Lee Nicolle

Lee Nicolle
  • Member

  • 5,659 posts
  • Joined: July 08

Posted 22 March 2012 - 22:39

Gas (as in gas not petrol because petrol isn't a gas you stupid Americans, it's a liquid) used to be really cheap in Oz then it got popular for cars and guess what happened ... dribble like below ...

Australian LPG prices reflect the fact that LPG is an internationally traded commodity and influenced by international prices. The international benchmark for the cost of Australian LPG is the Saudi Aramco Contract Price, also commonly called the Saudi CP. The Saudi CP is expressed in US dollars per tonne. As the international price is in US dollars, the Australian dollar exchange rate also affects the Australian price of LPG.

This is the same for all internationally traded commodities. Agricultural and natural resource products are similar to LPG, in that they are subject to the prevailing price in international commodity markets. Australia does not have an influence on LPG price benchmarks, as our production of LPG is small compared to worldwide production. The same is true for the Australian pricing of crude oil and refined products, which are also linked to international prices.


The thing is that Oz has massive gas reserves and daily excess and we not only export about 40% of it, we burn about 20% of it daily. The "International market equality" bullshit gets a bit hard to take. Saudi pulls their own fuel out of the ground so why are they 12 cents per litre, they're on the same International market ...

So America, take on the gas engines and it will just end up status quo - down down, deeper and down.

What Cheapie did not explain is that LPG prices in Australia have gone up from around 60c to 90c this year. So called international forces, bla bla bla. It is ofcourse price gouging the motorist, the same as the price of petrol is 20 or 30c too high also. Because the Supermarket chains now control the retail petrol market.

LPG is a by product of petrol production, though with a Labor / Green Government we may not have any refinerys left in Oz soon!
In SA our much lamented previous Treasurer played hard ball with Mobil who just closed up shop, losing the state a major asset

From what I understand, and may be wrong is that natural gas can be refined with minimal work to run LPG cars. Viable I do not know. But we evidently [in Oz] are selling gas to the Chinese for a few cents a litre.

But it seems cannot convert our coal fired Electricity generation to gas, which it seems we are giving away!

#21 gruntguru

gruntguru
  • Member

  • 5,175 posts
  • Joined: January 09

Posted 22 March 2012 - 23:30

From what I understand, and may be wrong is that natural gas can be refined with minimal work to run LPG cars. Viable I do not know.

I don't think it is straight forward to process NG into LPG. LPG cars could be re-tuned to run NG but the tank is the problem.

#22 Greg Locock

Greg Locock
  • Member

  • 4,477 posts
  • Joined: March 03

Posted 23 March 2012 - 00:16

From what I understand, and may be wrong is that natural gas can be refined with minimal work to run LPG cars. Viable I do not know.


No, that is not very easy to do. Roughly speaking CNG is methane, CH4. LPG is a mixture of propane and butane, both are longer chain hydrocarbons. To reformulate methane into longer chains you have to knock one or more of the hydrogens off each molecule. You could do that by passing it over coal in the presence of a suitable catalyst but it ain't going to be easy.

Modern refineries basically work the other way, breaking long chains into shorter ones.

Anyway I think the upshot is that solving the handling and storage problems (which are after all feasible on an industrial scale) is probably a better approach than synthesising propane from methane on a large scale.



#23 GreenMachine

GreenMachine
  • Member

  • 760 posts
  • Joined: March 04

Posted 23 March 2012 - 00:31

I don't think it is straight forward to process NG into LPG. LPG cars could be re-tuned to run NG but the tank is the problem.


Do you mean turn NG into LNG? Something to with the differences between the two (PG and NG) affecting the compression/liquifaction process? It seems cryogenic storage is necessary for LNG, not a very cost effective option for mass market vehicles, for the moment at least :rolleyes:

The buses are running on compressed NG, while the alternative is liquified PG ... my basic physics says that, other things being equal, there will be more combustion in a given tank of LPG than CNG? As a consumer of LPG for heating and cooking, I am also aware that I get less heat from my LPG than if I hook my appliances to NG, so that may be an offset?

On searching, not much of an offset

CNG's volumetric energy density is estimated to be 42% of liquefied natural gas's (because it is not liquefied), and 25% of diesel's

.
wiki entry for CNG

As an aside, I wonder how many people realise the pressures in those cylinders on top of the buses (or in CP's cement trucks) :eek:

#24 johnny yuma

johnny yuma
  • Member

  • 928 posts
  • Joined: May 07

Posted 23 March 2012 - 03:02

Possibly ,LeeNicolle intended to say LPG cars can be easily converted to run on CNG,which is true---but it is not true that Natural Gas can be easily converted into LPG.

And whether you use CNG or LNG, there will be either tank size and weight problems with CNG,or cyrogenic storage expenses with LNG.And a long queue at the only bowser within cooee ?

Question--since LPG is petroleum derived why should it be any cheaper than petrol (as we anglophiles say) or gas (as the good citizens of USA say).

#25 cheapracer

cheapracer
  • Member

  • 10,388 posts
  • Joined: May 07

Posted 23 March 2012 - 03:24

You ignorant foreign twit

Have a nice day. :love:


Oi!! You're the "Foreigner" with the funny accent.

I struggle to argue the "ignorant twit" bit though :lol:


#26 gruntguru

gruntguru
  • Member

  • 5,175 posts
  • Joined: January 09

Posted 23 March 2012 - 03:39

Question--since LPG is petroleum derived why should it be any cheaper than petrol (as we anglophiles say) or gas (as the good citizens of USA say).

Answer--Lower demand. Who wants to muck around with a pressurised liquid/gaseous fuel when there is a liquid alternative that is easy to store, decant, pump etc?

#27 cheapracer

cheapracer
  • Member

  • 10,388 posts
  • Joined: May 07

Posted 23 March 2012 - 03:56

My company has had a test fleet of Cummins gas powered concrete trucks for about 5 years now.


Out of interest how do you find the Chinese Italian IVECO trucks?


#28 Wuzak

Wuzak
  • Member

  • 3,463 posts
  • Joined: September 00

Posted 23 March 2012 - 05:25

Answer--Lower demand. Who wants to muck around with a pressurised liquid/gaseous fuel when there is a liquid alternative that is easy to store, decant, pump etc?


Isn't the real answer that the government(s) don't take LPG the same amount as petrol?



#29 Catalina Park

Catalina Park
  • Member

  • 5,668 posts
  • Joined: July 01

Posted 23 March 2012 - 06:13

Out of interest how do you find the Chinese Italian IVECO trucks?

You mean the Australian made International Iveco ACCO?
I don't think there is much in them from Europe or Asia. The Chassis and front suspension is made in Victoria, the motor, transmission, axles and rear suspension is made in the USA, I think the cabin is made in the USA or maybe Australia. Some of the brake valves are made in Mexico.

(or in CP's cement trucks)

They are not cement trucks. They are concrete trucks.

Edited by Catalina Park, 23 March 2012 - 06:14.


#30 Catalina Park

Catalina Park
  • Member

  • 5,668 posts
  • Joined: July 01

Posted 23 March 2012 - 06:29

What Cheapie did not explain is that LPG prices in Australia have gone up from around 60c to 90c this year. So called international forces, bla bla bla. It is ofcourse price gouging the motorist, the same as the price of petrol is 20 or 30c too high also. Because the Supermarket chains now control the retail petrol market.

LPG is a by product of petrol production, though with a Labor / Green Government we may not have any refinerys left in Oz soon!
In SA our much lamented previous Treasurer played hard ball with Mobil who just closed up shop, losing the state a major asset

From what I understand, and may be wrong is that natural gas can be refined with minimal work to run LPG cars. Viable I do not know. But we evidently [in Oz] are selling gas to the Chinese for a few cents a litre.

But it seems cannot convert our coal fired Electricity generation to gas, which it seems we are giving away!

Lee, the price of LPG has always been about 2/3 of the price of petrol. As we are paying around $1.50 for petrol it is about right that LPG should be near $1.00.

The gas that is being exported to China cheaply is natural gas.
LPG is Propane/Butane.
Natural gas is Methane.
We have an abundant supply of natural gas in Australia and selling it to China will not affect the price of gas for us. It certainly won't affect the price of LPG.

Natural Gas powered power stations are appearing all over the east coast or soon will be. I know of six gas power stations between Sydney and Melbourne that are either under construction or are going through planning.

#31 cheapracer

cheapracer
  • Member

  • 10,388 posts
  • Joined: May 07

Posted 23 March 2012 - 06:47

Natural gas is Methane.

Natural Gas powered power stations are appearing all over the east coast or soon will be.


Yup it was methane in coal seams we were drilling core samples for, expect a few power stations along or near the upper Newell Hwy soon enough.


#32 carlt

carlt
  • Member

  • 1,043 posts
  • Joined: June 09

Posted 23 March 2012 - 08:59

A friend of mine has been running a Ford Transit van on Methane[CNG] for the last 15 yrs
1.8L Pinto engine , dashboard adjustable dizzy on a bowden cable for ign timing
5 large welding gas bottles mounted underneath , and a small 'reserve' tank for LPG
he drives all over europe [ living in Italy]
His experience is that 'Gas' outlets are becoming more scarce - he needs to now carefully plan his journeys , whereas before he found it no problem to fill up on natural gas

There is a definite power loss , combined with the added weight , over LPG and 'Spirit of Refined Crude Oil' [ is that an accepted multicultural term ? :p ]


#33 bigleagueslider

bigleagueslider
  • Member

  • 838 posts
  • Joined: March 11

Posted 23 March 2012 - 22:22

Natural gas makes an excellent SI engine fuel. The only issue for automotive use is energy density and storage volume. Even compressed to over 200 bar, it remains a gas at ambient temps. Thus it requires a large amount of storage volume. This is not a problem for transit buses or short haul trucks which can be refueled regularly, but limits the range of cars. Honda sells a very nice NG Civic in the US, but its unrefueled range is only about 200 miles.

The main benefit of using NG as an automotive fuel is that there is a huge global supply of it, it is widely available, and new drilling technology has greatly reduced its price.

#34 gruntguru

gruntguru
  • Member

  • 5,175 posts
  • Joined: January 09

Posted 23 March 2012 - 22:55

unrefueled range

Interesting term. Military aircraft? Can't we just say "range"?

The main benefit of using NG as an automotive fuel is that there is a huge global supply of it, it is widely available, and new drilling technology has greatly reduced its price.

Wait till I perfect my technology for capturing cow farts. The price will plummet.

#35 GeoffR

GeoffR
  • Member

  • 483 posts
  • Joined: January 04

Posted 24 March 2012 - 01:26

By sheer coincidence I followed a Toyota Aurion through Hobart this morning which was emblazoned with "Tasmania's first natural gas powered passenger vehicle" (or something like that). And people say that Tasmania is behind the times!  ;)

#36 Catalina Park

Catalina Park
  • Member

  • 5,668 posts
  • Joined: July 01

Posted 24 March 2012 - 02:23

There is a fleet of CNG cars in Goulburn. They have their own refuelling pump at their depot. They have been using CNG for about 10 years or more.

#37 cheapracer

cheapracer
  • Member

  • 10,388 posts
  • Joined: May 07

Posted 24 March 2012 - 02:45

By sheer coincidence I followed a Toyota Aurion through Hobart this morning which was emblazoned with "Tasmania's first natural gas powered passenger vehicle" (or something like that). And people say that Tasmania is behind the times! ;)


What after the 50 million of them in China they mean?


Wait till I perfect my technology for capturing cow farts. The price will plummet.


There's a job you can really get your head into.


#38 bigleagueslider

bigleagueslider
  • Member

  • 838 posts
  • Joined: March 11

Posted 24 March 2012 - 05:43

Interesting term. Military aircraft? Can't we just say "range"?


OK. Does "range" imply one way or round trip? :)

Incidentally, the published range for Honda Civic G is based on a tank pressure of 3800 psig. But most NG refueling stations can only fill the tank to 3000 psig.

#39 gruntguru

gruntguru
  • Member

  • 5,175 posts
  • Joined: January 09

Posted 24 March 2012 - 06:44

OK. Does "range" imply one way or round trip? :)

Not sure if anything is implied by the term, but the convention is "distance" travelled not "displacement". :)

Advertisement

#40 rory57

rory57
  • Member

  • 89 posts
  • Joined: November 10

Posted 24 March 2012 - 13:49

[quote name='gruntguru' date='Mar 23 2012, 22:55' post='5616224'
Wait till I perfect my technology for capturing cow farts. The price will plummet.
[/quote]

I think you will find cow fart is already very cheap.

Looking at the video in Saudoso's link and other related youtube videos is a salutary lesson about the amount of energy stored in 70 odd litres of gas @ 200 bar. It is notable that although the cars have been completely blown apart by the gas explosion, no evidence of fire is seen. Next time I ride in a Hong Kong taxi I will be thinking about that CNG bottle a few inches behind me......

#41 mariner

mariner
  • Member

  • 1,358 posts
  • Joined: January 07

Posted 24 March 2012 - 14:07

This is slightly OT but the connection is that Stirling engines were looked at for cars at the beginning of pollution regulations in the 1970's.

My grandfather was an engineer ( in the machinist sense) starting just before WW1. He and his brother tried motorbike making without any great sucess although, believe it or not the brother went on to be an Italian racecar builder before Enzo Ferrari!

I rememebr my grandfathers collection of tools and things when he was retired. I still have a few of the beautiful hand forged L handle sockets. The most interesting item in his collection was a stationary hot air or Stirling engine. It was powered by an external heater using normal town ( coal) gas. I can remember him running a rubber tube from the gas fire and getting the burner going under the power cylinder. After a long wait you would swing the very big flywheel and it started running with a lovely quiet " chuff chuff " noise.

These kind of hot air engines were used in big old houses to rum a small dynamo for electric lighting as whilst gas pipes had been laid in many towns an electirc grid was rare pre WW1 in England.

They didnt put out much power for the size but would run reliably for a very long time. We gave the engine to the London Science Museum when he died but I have no idea if they ever used it.

The usual Wiki article is here - http://en.wikipedia....Stirling_engine
it was a beta type engine

Edited by mariner, 24 March 2012 - 14:11.


#42 Canuck

Canuck
  • Member

  • 1,638 posts
  • Joined: March 05

Posted 24 March 2012 - 14:22

If natural gas gets any cheaper here, they'll have to pay you to take it. Price today is $2.28 per million btu. My house and hot water are both heated with it and when the day comes to replace the dryer or the 20+ year old stove, they'll be gas appliances too.

#43 cheapracer

cheapracer
  • Member

  • 10,388 posts
  • Joined: May 07

Posted 24 March 2012 - 15:13

This is slightly OT but the connection is that Stirling engines were looked at for cars at the beginning of pollution regulations in the 1970's.


The "Big 3" got surprisingly deep into it actually.

http://blog.hemmings...tirling-engine/

One advantage that is rarely mentioned for a Stirling engine is high altitudes don't bother it and it fact usually as it gets higher, it gets colder, so they perform better because the temp difference is greater - would suit small aircraft no end.

Here is a commercially available gas powered Stirling generator from New Zealand ..

http://www.whisperge...whispergen.html

http://www.whispergen.com/main/HOME/



#44 Wuzak

Wuzak
  • Member

  • 3,463 posts
  • Joined: September 00

Posted 24 March 2012 - 23:25

I rememebr my grandfathers collection of tools and things when he was retired. I still have a few of the beautiful hand forged L handle sockets. The most interesting item in his collection was a stationary hot air or Stirling engine. It was powered by an external heater using normal town ( coal) gas. I can remember him running a rubber tube from the gas fire and getting the burner going under the power cylinder. After a long wait you would swing the very big flywheel and it started running with a lovely quiet " chuff chuff " noise.

These kind of hot air engines were used in big old houses to rum a small dynamo for electric lighting as whilst gas pipes had been laid in many towns an electirc grid was rare pre WW1 in England.



Sounds like an excellent power suppliment for parliament houses everywhere....

#45 Greg Locock

Greg Locock
  • Member

  • 4,477 posts
  • Joined: March 03

Posted 24 March 2012 - 23:51

Most of the secondary virtues of a Stirling are a byproduct of its real failing, it is huge machine with a tiny power output. Real world efficiencies can be quite high (but rather less than the headline number due to the burner etc), but then a decent turbo diesel isn't /that/ far off, and its power/weight, or power/installed volume, is what, a factor of 4-10 different?

Incidentally the best working fluid for them is hydrogen or helium, thermodynamically, but sealing is a huge issue.Oh, the wiki article cobers all this and more

http://en.wikipedia....Stirling_engine

One nice use for them is in a sun powered system, lots of mirrors and a very busy little engine.

#46 bigleagueslider

bigleagueslider
  • Member

  • 838 posts
  • Joined: March 11

Posted 26 March 2012 - 01:20

If natural gas gets any cheaper here, they'll have to pay you to take it. Price today is $2.28 per million btu. My house and hot water are both heated with it and when the day comes to replace the dryer or the 20+ year old stove, they'll be gas appliances too.


Canuck,

The free market laws of supply and demand sometimes work in your favor! Recent advances in drilling technology have made it profitable to extract the massive reserves of NG that were previously uneconomical to produce. The economics that surround oil and gas markets are complex, and I personally find the subject quite interesting. Over the past few years, crude oil has jumped in price while NG has plummeted. Oil prices have increased mostly due to world political issues, while NG prices have fallen due to technology developments.

Eventually, NG prices will settle-out a bit higher than they currently are, while oil prices will settle-out much lower than they currently are. The only real use for crude oil is for transportation fuels like gasoline, diesel and jet fuel. On the other hand, there are lots of uses for NG, such as electrical power generation, as feedstocks for chemical and plastics production, or for production of agricultural fertilizers.

Enjoy that cheap NG while it lasts. North American supplies are projected to run out sometime in the next 150 years.

slider

#47 gruntguru

gruntguru
  • Member

  • 5,175 posts
  • Joined: January 09

Posted 26 March 2012 - 03:56

The only real use for crude oil is for transportation fuels like gasoline, diesel and jet fuel.

Is that all. Should last for ages then. :)

#48 Wuzak

Wuzak
  • Member

  • 3,463 posts
  • Joined: September 00

Posted 26 March 2012 - 05:10

Doesn't crude oil get used for other products - like plastics?

#49 gruntguru

gruntguru
  • Member

  • 5,175 posts
  • Joined: January 09

Posted 26 March 2012 - 06:59

Yep, plus lubricants, chemicals etc. Small potatos compared to the volume burned as fuels though, but perhaps more difficult to substitute.

#50 Catalina Park

Catalina Park
  • Member

  • 5,668 posts
  • Joined: July 01

Posted 26 March 2012 - 09:26

Natural gas can be converted to a liquid fuel by the Fischer–Tropsch process. So when oil gets too expensive or scarce there will still be a way of fuelling trucks, trains and aircraft. (and maybe even Autogyros)