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Author
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Topic: Making engines more efficient
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Agent 204
rabble-rouser
Babbler # 4668
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posted 26 March 2005 08:41 AM
In my class on waste management, we went on a field trip to a landfill, and among the things we were shown was a bank of enormous engines, running on landfill gas, which were being used to generate electricity that is sold to Hydro One (enough to power around 3200 homes, actually). One of the things we were told was that in the near future, they are going to be adding devices to the engines that collect heat from the exhaust and use this to boil pentane and spin a turbine. This will be a closed system, so the pentane will not be consumed, and it is expected to almost double the amount of electricity produced by the system.My question is, how scalable is this? Will a car engine produce enough heat to get a useful amount of juice out of it, or is this something limited to larger engines like these ones? If the former, this would be a terrific addition to hybrid cars, further reducing their fuel consumption. Thoughts?
From: home of the Guess Who | Registered: Nov 2003
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LeftRight
rabble-rouser
Babbler # 2379
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posted 26 March 2005 10:22 PM
quote:
Originally posted by LeftRight:
Two thoughts come to mind: 1)if it is possible to convert heat directly to electricity, this would cut out a lot of the mechanisms in between.
http://www.rabble.ca/babble/ultimatebb.cgi?ubb=get_topic&f=21&t=001148&p=
last message on that thread
From: Fraser Valley | Registered: Mar 2002
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quagmire
rabble-rouser
Babbler # 8028
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posted 26 March 2005 10:38 PM
quote:
Originally posted by Mike Keenan:
Thanks for the link.I wonder if the efficiency of diesels is enough to compensate for the greater carbon content of diesel fuel? Of course if biodiesel can be done on a big scale this will be a non-issue, but I wonder which produces more CO2 per kilometre, gas or diesel? [ 26 March 2005: Message edited by: Mike Keenan ]
I'd guess that the lower pumping losses and higher compression of the diesel would still make it more efficient in miles per pound of carbon, particularily if it was turbocharged and aftercooled.
Hydraulicaly activated valves are coming soon, they are here already on some of the monster sized marine engines. The 100,000 horsepower Sulzer uses them. It spins a whole 98 rpm.
http://www.bath.ac.uk/~ccsshb/12cyl/
http://www.wartsila.com/?_nfpb=true&_pageLabel=shippower_en
Caterpillar has a new generation of high speed and low speed diesels on the drawing board, I'm not sure what the details are but they will be electronic engines from the ground up, not just old designs with electronic fuel injection systems added. The HEUI system should be the standard for a while for Cat. [ 28 March 2005: Message edited by: quagmire ] [ 28 March 2005: Message edited by: quagmire ]
From: Directly above the center of the Earth | Registered: Jan 2005
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Agent 204
rabble-rouser
Babbler # 4668
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posted 01 April 2005 04:44 PM
quote:
Originally posted by quagmire:
I'd guess that the lower pumping losses and higher compression of the diesel would still make it more efficient in miles per pound of carbon, particularily if it was turbocharged and aftercooled.
Hydraulicaly activated valves are coming soon, they are here already on some of the monster sized marine engines. The 100,000 horsepower Sulzer uses them. It spins a whole 98 rpm.
http://www.bath.ac.uk/~ccsshb/12cyl/
http://www.wartsila.com/?_nfpb=true&_pageLabel=shippower_en
Caterpillar has a new generation of high speed and low speed diesels on the drawing board, I'm not sure what the details are but they will be electronic engines from the ground up, not just old designs with electronic fuel injection systems added. The HEUI system should be the standard for a while for Cat.
That Sulzer engine is amazing!The engines at the landfill were Caterpillar engines, actually, but they were spark ignition, not diesel. (BTW, if you had a compression-ignition engine that ran on methane or the like, would it still be called a diesel engine?) Incidentally, are all modern automotive diesels now EFI jobs, or are some of them still all-mechanical?
From: home of the Guess Who | Registered: Nov 2003
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quagmire
rabble-rouser
Babbler # 8028
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posted 01 April 2005 05:36 PM
I'd guess that they are all electronicly controlled except maybe the quite small ones. I'm more familiar with the larger Cat mining equipment than any of the others these days.
The landfill ones you saw sound like Cat 3600 engines, they are available as Diesels or spark ignition and in 6,8,12, 16 or 18 cylinders. Most of the ones in Alberta are spark ignited and burn natural gas in the compressor stations. Caterpillar refers to them as gas engines.
The 3600 engines running generators in the north generally have exhaust gas boilers on them.
I saw some big MAN's running 12 megawatt generators, they were plenty impressive. There are a lot of interesting ideas in some of those big engines. Cooper-Besner (sp?) built some big V 12's that used a master rod and a pony rod for each pair of cylinder similar to the the aircraft radials.
There are a lot of new ideas being tried in the truck engine market to lower the pollution from them.
As a bit of interest, Detroit Diesel used to build some big two stroke diesels, the 149 series. They were 149 cubic inches per cylinder and put out a max of 125 hp per cylinder. They built two engine blocks, a V6 and a V8. The engines were available as V8's, V12's, V16's, and V20's, but not V6's.
How'd they do that?
The V8 was one engine block, the V12 was two V6's bolted together with the right amount of blowers and turbochargers, the V16 was two V8's etc, and the V20 was a V6, a V8, and another V6 bolted together with three blowers and six turbos.
I think they have gone the way of the dinosaur because of emissions and fuel economy. The 4 strokes are just more fuel efficient.
Cat builds a 3000 plus horsepower diesel called a 3524, it's two 3512 v12's coupled together and it powers the 797 mining truck, which is a big bruiser.
Cheers.[ 01 April 2005: Message edited by: quagmire ] [ 01 April 2005: Message edited by: quagmire ]
From: Directly above the center of the Earth | Registered: Jan 2005
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