Two stroke diesel, turbo compound engines

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Bruno Ogorelec
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Post by Bruno Ogorelec » Tue Jan 15, 2008 7:56 pm

Viv, I had no idea they had gone so far. Not quite the configuration I'd have chosen (I like the two-crankshaft one better) but who am I to argue? This is a wonderful product. I am really amazed. (Provided that the claims are true, of course.)

Proves the point I have been making very often, to a great number of skeptical listeners -- that so many wickedly intelligent designs have fallen by the wayside over the course of the 20th century, for spurious, often totally stupid, reasons.

Next thing, mark my words, boundary layer free radical ignition engines by Honda.

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Sulzar?

Post by Viv » Tue Jan 15, 2008 8:50 pm

What I love is the way its based on the Sulzar marine engines but arranged as a flat twin, that and the fact that they have made a suitcase sized 5 kw generator from a marine engine the size of a house;-)

I still like the twin crank version or the single crank with rocker arms of the T3 type as you say who are we to argue.

The power to weight ration of these engines with the SFC of a diesel will be formidable competition in the market place, couple one of these to a modern composite multi-blade propellor and you have a powerful solution.

Now all it needs is a bigger scavenging blower and turbo section;-)

Viv
Last edited by Viv on Thu Jan 17, 2008 2:40 am, edited 1 time in total.
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did you spot the additional oval cylinders

Post by Viv » Thu Jan 17, 2008 2:38 am

You have got to assume my sense of humor is in full swing;-)

look at the picture again and notice how nicely the internal oval of the cylinder liner is machined, then wonder why? the small dark tube is the cylinder for the pistons, lower piston attached in the normal way to the crank , upper piston has an oddly oval looking crosshead for the connecting rods to attach it back to the main crank.

? its a two stroke diesel it needs scavenging air, were does it come from in such a compact layout?

Enjoy

Viv
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Post by tufty » Thu Jan 17, 2008 6:14 am

Oval pistons, you say?

Image

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Re: did you spot the additional oval cylinders

Post by Bruno Ogorelec » Thu Jan 17, 2008 6:24 am

Viv wrote:You have got to assume my sense of humor is in full swing;-)

look at the picture again and notice how nicely the internal oval of the cylinder liner is machined, then wonder why? the small dark tube is the cylinder for the pistons, lower piston attached in the normal way to the crank , upper piston has an oddly oval looking crosshead for the connecting rods to attach it back to the main crank.

? its a two stroke diesel it needs scavenging air, were does it come from in such a compact layout?

Enjoy

Viv
No, it's got round pistons as far as I can see, unlike the Honda.

I see no blower anywhere. The piston is not stepped, as in the Woolfe layout. So, I must assume it's loop scavenging, with intake into the crankcase, with piston bottoms pumping the fresh charge in and out of crankcase through scavenging ports.

But, for that, the cylinders would have to be staggered, as in a boxer engine (like a Koenig 2-stroke, for instance) so that the pistons move in opposite directions. As far as I can see, those two pistons are not staggered. They look like being mounted on the same crankpin.

Do the upper pistons pump the fresh charge, between the top of the crosshead and the cylinder cover, or what? The pushrod tunnels could be used as ports.

Beats me, frankly.

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Post by Viv » Thu Jan 17, 2008 3:38 pm

tufty wrote:Oval pistons, you say?

Image
You need new glasses Simon, her pistons are definitely not oval;-)

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Re: did you spot the additional oval cylinders

Post by Viv » Thu Jan 17, 2008 3:48 pm

Bruno Ogorelec wrote:
Viv wrote:You have got to assume my sense of humor is in full swing;-)

look at the picture again and notice how nicely the internal oval of the cylinder liner is machined, then wonder why? the small dark tube is the cylinder for the pistons, lower piston attached in the normal way to the crank , upper piston has an oddly oval looking crosshead for the connecting rods to attach it back to the main crank.

? its a two stroke diesel it needs scavenging air, were does it come from in such a compact layout?

Enjoy

Viv
No, it's got round pistons as far as I can see, unlike the Honda.

I see no blower anywhere. The piston is not stepped, as in the Woolfe layout. So, I must assume it's loop scavenging, with intake into the crankcase, with piston bottoms pumping the fresh charge in and out of crankcase through scavenging ports.

But, for that, the cylinders would have to be staggered, as in a boxer engine (like a Koenig 2-stroke, for instance) so that the pistons move in opposite directions. As far as I can see, those two pistons are not staggered. They look like being mounted on the same crank-pin.

Do the upper pistons pump the fresh charge, between the top of the crosshead and the cylinder cover, or what? The push-rod tunnels could be used as ports.

Beats me, frankly.
The oval cross head has a blue seal on it so it looks like an air piston, below it is the round combustion piston by the looks of it Bruno, look at the row of components along the bottom and the second one is a reed valve.

Its stepped but not as we know it in the woolfe, for scavenging you need a couple of times the cylinder volume to blow out the exhaust gases so crankcase pumping wont work as its too low a volume.

It looks like the top of the stepped piston (crosshead) is the air piston and below it is the combustion piston but acting now as the timing valve to close off the flow, it s neater arrangement than the traditional method.


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Re: did you spot the additional oval cylinders

Post by Bruno Ogorelec » Thu Jan 17, 2008 4:35 pm

Viv wrote:for scavenging you need a couple of times the cylinder volume to blow out the exhaust gases so crankcase pumping wont work as its too low a volume.
Um.... it sure as hell worked on all the two strokes I have owned.

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Re: did you spot the additional oval cylinders

Post by Viv » Thu Jan 17, 2008 4:52 pm

Bruno Ogorelec wrote:
Viv wrote:for scavenging you need a couple of times the cylinder volume to blow out the exhaust gases so crankcase pumping wont work as its too low a volume.
Um.... it sure as hell worked on all the two strokes I have owned.
:-)

I don't think you can claim those as being the same type of scavenging requirement!

My old Villiers 2T or Arial Leader were two strokes but not like diesel two strokes

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Re: did you spot the additional oval cylinders

Post by tufty » Thu Jan 17, 2008 8:10 pm

Viv wrote:
Bruno Ogorelec wrote:
Viv wrote:for scavenging you need a couple of times the cylinder volume to blow out the exhaust gases so crankcase pumping wont work as its too low a volume.
Um.... it sure as hell worked on all the two strokes I have owned.
:-)

I don't think you can claim those as being the same type of scavenging requirement!

My old Villiers 2T or Arial Leader were two strokes but not like diesel two strokes

Viv
Even allowing for the same stroke, one might say that the seemingly larger bore on the second piston (oval or not, haha) would make for a greater volume for scavenging, no?

Sorry, I'm durnk.

Simon

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Post by Bruno Ogorelec » Tue Jan 22, 2008 10:03 pm

Viv,

Something for you. Please study this cutaway of the engine carefully. Takes some time before you see what's what -- but it's worth the effort.

Remember our conversation on stepped pistons?

the only thing I know about this is that it's Pratt & Whitney.
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Another diesel engine start-up comes out of stealth

Post by Viv » Thu Jan 24, 2008 9:02 pm

Another diesel engine start-up comes out of stealth

Actually thats the name of the article but again it seems this is the green topic of the moment

http://www.news.com/8301-11128_3-985758 ... 47-1_3-0-5

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Double acting

Post by Viv » Fri Jan 25, 2008 5:37 pm

Bruno Ogorelec wrote:Viv,

Something for you. Please study this cutaway of the engine carefully. Takes some time before you see what's what -- but it's worth the effort.

Remember our conversation on stepped pistons?

the only thing I know about this is that it's Pratt & Whitney.
Hi Bruno

Yes I have seen this type of pump before but never a double acting version like this, very nice

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Re: Double acting

Post by Bruno Ogorelec » Fri Jan 25, 2008 5:48 pm

Aw, Viv, it ain't a pump. It's a Pratt & Whitney PT-1 free piston engine, a gas generator for a turbine. Used two opposed whopping BIG stepped pistons, the small bore step for compression and expansion and the big bore for aspiration. Must have packed a punch. Here's the outside.
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Wow

Post by Viv » Fri Jan 25, 2008 5:54 pm

Wow bet that rattled a bit;-) I see the gas pistons at the ends then to stop it slapping the heads off.

I worked on stepped piston pumps based on this principle that worked off compressed air and also hydraulic oil, they were used for boosting pressure.

Never saw a free piston engine with stepped pistons though

Viv
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