Scotty C
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Registered: 6th Nov 05
Location: Kidderminster Drives: 1.6 16v Sport
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quote: Originally posted by Steve X16XE
well kids. how's school been today?
Got too confusing on after page two TBH
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Robin
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Registered: 7th Jan 04
Location: Northants Drives: Clio 182 Cup
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Are we moving away from cars now then?
does this mean we start talking about scram, ram, turbine and turboprops?
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Steve X16XE
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Registered: 31st Dec 06
Location: Barnsley, South Yorkshire
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Steve X16XE
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tom_simes
Show Staff Organiser: South Wales Premium Member
Registered: 12th Jan 05
Location: Undy, Newport Drives: Skoda Octavia vRS estate
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How are you Jim?
Yes Robin, it seems we are.
Has anybody explained the Diesel cycle?
Or Carnot? I jumped in at page 8
[Edited on 09-03-2007 by tom_simes]
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Steve X16XE
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Steve X16XE
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Location: Barnsley, South Yorkshire
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Steve X16XE
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Location: Barnsley, South Yorkshire
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The Diesel Cycle is an air-standard model of the actual cycle described above. The Diesel Cycle differs from the Otto Cycle only in the modeling of the combustion process: In a Diesel Cycle, it is assumed to occur as a reversible constant pressure heat addition process, while in an Otto Cycle, the volume is assumed constant.
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Scotty C
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Registered: 6th Nov 05
Location: Kidderminster Drives: 1.6 16v Sport
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You're loving this arent you Steve?
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SVM 286
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Registered: 13th Feb 05
Location: pain
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Not bad Tom, how's yaself mate?
I scan read a lot of the thread so i'm not sure.
Suffice to say, bags of compression = super heated air, introduce atomised fuel at up to 1050 bar of pressure and blammo, you have combustion.
That's pretty much yer diseasal.
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Steve X16XE
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Location: Barnsley, South Yorkshire
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Lovin it (but very tired)
So why does the diesel engine be so economical coz it weighs more than a petrol engine?
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Robin
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Registered: 7th Jan 04
Location: Northants Drives: Clio 182 Cup
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It's more efficient than the petrol engine, something like 80% as opposed to 15% of the petrol (figures are wrong, but you get the idea)
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tom_simes
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Registered: 12th Jan 05
Location: Undy, Newport Drives: Skoda Octavia vRS estate
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I did a module in Thermodynamics for my degree last semester, so I know the diesel, otto and brayton cycles relatively well!
I'm good thanks Jimbo, don't have to be in uni 'til 1 tomorrow, so a nice lie in to be had in the morning I think!
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Steve X16XE
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but why is it?
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Steve X16XE
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Diesel engines are nevertheless more efficient than Otto cycle engines overall, but only during partial load with fuel cut-off at part of the power stroke. Most land vehicles rarely run at the maximum rated power of an engine. Unless the vehicle is at full stroke injection, when the pedal is 'floored', it is at partial rated power. Since diesel engines use the heating effect of compressing air to ignite fuel, it can inject as little or as much fuel as the situation demands. It is important to note that Otto cycle engines can be more efficient than Diesel cycle engines, but only when the engine is running at or near maximum power.
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tom_simes
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Registered: 12th Jan 05
Location: Undy, Newport Drives: Skoda Octavia vRS estate
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quote: Originally posted by Robin
It's more efficient than the petrol engine, something like 80% as opposed to 15% of the petrol (figures are wrong, but you get the idea)
Otto cycle is approximately 25-30% efficient, while diesel is about 40-45%.
Carnot cycle is 100% efficient.
(taken from 'Thermodynamics - An Engineering Approach', my course text book)
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Steve X16XE
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Sleep for me now guys. How you enjoyed the show.
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SVM 286
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Registered: 13th Feb 05
Location: pain
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quote: Originally posted by Steve X16XE
Lovin it (but very tired)
So why does the diesel engine be so economical coz it weighs more than a petrol engine?
Very precisely measured fuel and not much of it at that, plus enormous torque so fewer revs required and more work done with less fuel burnt.
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Steve X16XE
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Location: Barnsley, South Yorkshire
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I'll leave you guys with this to read.
http://www.answers.com/topic/carnot-cycle-2
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Steve X16XE
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SVM 286
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Registered: 13th Feb 05
Location: pain
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Night Steve.
Sweet dreams mate, probably of little engines.
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Robin
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Registered: 7th Jan 04
Location: Northants Drives: Clio 182 Cup
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How about 4 Cylinders, 32 valves, oval pistons, 8 conrods and 8 carbs?
In a bike.
http://www.vsource.org/VFR-RVF_files/Brochures_NR750.htm
http://en.wikipedia.org/wiki/Honda_NR
THAT was clever.
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SVM 286
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Registered: 13th Feb 05
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Saw one at Goodwood.
JR was raving
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SVM 286
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Registered: 13th Feb 05
Location: pain
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quote: Originally posted by tom_simes
I'm good thanks Jimbo, don't have to be in uni 'til 1 tomorrow, so a nice lie in to be had in the morning I think!
Lucky sod
Gotta be at work at 09:30
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Steve X16XE
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Location: Barnsley, South Yorkshire
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now i'm off.
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