Omega Owners Forum
Chat Area => General Discussion Area => Topic started by: Marks DTM Calib on 19 October 2009, 14:50:46
-
.....can anybody guess whats special about this engine type?
(http://i23.photobucket.com/albums/b394/Marks_DTM_Calib/petrol-turbo-engine.jpg)
-
Surely with differant size cam pullys the valve timing is going to be all over the place :-/
-
The middle cylinder appears to be designed to act as two cylinders, so maybe it fires twice on the cycle. i.e maybe the firing order would be 1213 or such like. Like a V4 but smaller.
I'm wrong aren't I? :-[ :-X
-
and No.1 and 3 cylinders seem to be missing 2 valves per cylinder,unless its just drawn that way to make it easier to see other details on the drawing. :-/
It looks like one camshaft is going to turn a lot faster than the other,cant think why though,probably something to do with emissions,isnt everything these days. :-/
-
Quick guess - 2 stroke with compounding
-
Looks like a 2 stroke and 4 stroke combined :-?
-
Hmm. I'd be interested to see the manifolds.
Looks like an idea from the age of steam re-hashed if I'm on the right lines...
Either that or the chap who did the valvegear had had one too many.
Kevin
-
Variation on a two stroke? Single central piston acts as the crankcase would on a two stroke but the engine doesn't have to run a total loss oiling system and the piston rings don't get chewed up due to transfer ports in the side of the barrel?
Thinking a bit harder.....
The two outer pistons will behave like a (japanese) 4 stroke parallel twin and the big central piston will force charge air into alternate pistons.
-
Looking at the crank arrangement it alternates between fireing on the two outside cylinders at the same time and firing on the centre cylinder.
-
Quick guess - 2 stroke with compounding
I think you're half way there.. :P
Kevin
-
This is what it brought to mind for me...
http://en.wikipedia.org/wiki/Steam_engine#Multiple_expansion_engines
Kevin
-
Ideas
Cylinder 2 is the compressor, 1 & 3 are the power cylinders
or
Cylinder 1 and 2 are high pressure and cylinder 2 low pressure
-
Ideas
Cylinder 2 is the compressor, 1 & 3 are the power cylinders
or
Cylinder 1 and 2 are high pressure and cylinder 2 low pressure
Looking at how the cams are arranged I'd say the latter. :y
Kevin
-
Hmm. It's actually rather clever. The efficiency of a high compression ratio, without the losses or the detonation issues.
Kevin
-
Looks like a 2 stroke and 4 stroke combined :-?
A 2 stroke wouldnt have a pair of valves per cylinder though. :-/
-
Standard engine, with 1 cylinder having 4 valves and a bigger combustion area to suit.
Extra cam only works the extra 2 valves.
Bigger centre cylinder balances out the 2 smaller ones as well.
-
Standard engine, with 1 cylinder having 4 valves and a bigger combustion area to suit.
Extra cam only works the extra 2 valves.
Bigger centre cylinder balances out the 2 smaller ones as well.
But look at how the cams are driven. The exhaust valve on the centre cylinder opens once per revolution. :-?
Kevin
-
And the valves on number 1 &3 cylinders are both driven from the same cam,not 1 inlet and 1 exhuast valve each. :-/
-
And the valves on number 1 &3 cylinders are both driven from the same cam,not 1 inlet and 1 exhuast valve each. :-/
Yep, and that cam rotates at half crankshaft speed. Therefore, 1 and 3 are definitely 4 stroke cylinders. Looking at the lobes that drive their valves the valve timing looks pretty conventional too.
.. And the other pair of valves on cylinder 2 are driven by the "4 stroke" cam. The timing of those valves is the same as the adjacent exhaust valves on cylinders 1 & 3. :-/
Can you see why I wanted to see the manifolds yet?
Kevin
-
Hmm. I'd be interested to see the manifolds.
Looks like an idea from the age of steam re-hashed if I'm on the right lines...
Either that or the chap who did the valvegear had had one too many.
Kevin
That is exactly what I think Kevin. Compounding. Two high pressure cyclinders and one low. :y :y :y :y
-
Taking into account that the inlet cams are moving much faster, it looks like that all the valves on the center cylinder will all be open at the same time :-?
What ever it is it'll never be a replacement for a v8 so I dont like it :D
-
:-? :-?
3 cylinder with 4 stroke me thinks..really interesting set up
-
Now you are starting to question yourselves. ::)
Both valves inlet and exhaust can be driven off the same camshft.
What is the rotational direction of the crank.
Which valves are the inlet valves?
Is this just an optical illussion psstake.
Is it indeed a petrol engine.
The mind boggles. :o :o :o ::) :-X :-/
-
My theory....
Big centre piston acts as an air pump, camshaft running at crank speed controls intake valves to big piston.
Outer two pistons take turns to be charged with air from the big centre piston.
.. And the other pair of valves on cylinder 2 are driven by the "4 stroke" cam. The timing of those valves is the same as the adjacent exhaust valves on cylinders 1 & 3. Undecided
The reason why the these valves open together is so the air from the big piston can pass into the little one.
-
Is it one of these compressed air engines? :-?
-
OK. My whole theory.
Two little pistons 1&3 work exactly like a conventional 4 stroke engine. Intake valves closest to the ends of the engine. Exhaust valves at the centre. Crank rotates clockwise viewed from the front pulley (cam belt tensioner arrangement proves that).
Exhaust valves from 1 and 3 feed into the large central cylinder so the exhaust manifold just connects the two pairs of valves at the centre rear of the head as we look at it.
Gases (still expanding) from the little cylinders exert pressure on the large piston thus recovering a bit more energy from the charge, increasing efficiency. Large piston exhausts through the pair of valves nearest to us, and driver from the front cam at crank speed (engine will exhaust once per crank rotation so the middle cylinder is effectively a 2 stroke).
No reason why it wouldn't scale up to a V8. Would be 12 cylinders by then though. 8-)
Kevin
-
OK. My whole theory.
Two little pistons 1&3 work exactly like a conventional 4 stroke engine. Intake valves closest to the ends of the engine. Exhaust valves at the centre. Crank rotates clockwise viewed from the front pulley (cam belt tensioner arrangement proves that).
Exhaust valves from 1 and 3 feed into the large central cylinder so the exhaust manifold just connects the two pairs of valves at the centre rear of the head as we look at it.
Gases (still expanding) from the little cylinders exert pressure on the large piston thus recovering a bit more energy from the charge, increasing efficiency. Large piston exhausts through the pair of valves nearest to us, and driver from the front cam at crank speed (engine will exhaust once per crank rotation so the middle cylinder is effectively a 2 stroke).
No reason why it wouldn't scale up to a V8. Would be 12 cylinders by then though. 8-)
Kevin
Correct, it is indeed a 5 stroke engine and is being developed by the legendary high performance engine maker, Ilmor
so, if we consider
http://www.omegaowners.com/forum/YaBB.pl?num=1222761905
We get all the benefits of opening the exhaust valve earlier and still get great economy as we can recover additional power using the thrid stroke!
And how may you ask can you get a 5 stroke engine, simples, there are only 5 truely active strokes
-
More info here:
http://www.ilmor.co.uk/concept_5-stroke_1.php
(http://www.ilmor.co.uk/images/concept/5-stroke_engine4.jpg)
-
OK. My whole theory.
Two little pistons 1&3 work exactly like a conventional 4 stroke engine. Intake valves closest to the ends of the engine. Exhaust valves at the centre. Crank rotates clockwise viewed from the front pulley (cam belt tensioner arrangement proves that).
Exhaust valves from 1 and 3 feed into the large central cylinder so the exhaust manifold just connects the two pairs of valves at the centre rear of the head as we look at it.
Gases (still expanding) from the little cylinders exert pressure on the large piston thus recovering a bit more energy from the charge, increasing efficiency. Large piston exhausts through the pair of valves nearest to us, and driver from the front cam at crank speed (engine will exhaust once per crank rotation so the middle cylinder is effectively a 2 stroke).
No reason why it wouldn't scale up to a V8. Would be 12 cylinders by then though. 8-)
Kevin
Correct, it is indeed a 5 stroke engine and is being developed by the legendary high performance engine maker, Ilmor
so, if we consider
http://www.omegaowners.com/forum/YaBB.pl?num=1222761905
We get all the benefits of opening the exhaust valve earlier and still get great economy as we can recover additional power using the thrid stroke!
And how may you ask can you get a 5 stroke engine, simples, there are only 5 truely active strokes
I'm the same as my wife will tell you ::)
-
More info here:
http://www.ilmor.co.uk/concept_5-stroke_1.php
(http://www.ilmor.co.uk/images/concept/5-stroke_engine4.jpg)
That's confused me. I thought they had become Mercedes and were powering the Brawns, Maclarens etc.
-
Smart stuff, I knew the correct answer all the time of course. :-[ :-[
Well done Kevin.
-
More info here:
http://www.ilmor.co.uk/concept_5-stroke_1.php
(http://www.ilmor.co.uk/images/concept/5-stroke_engine4.jpg)
That's confused me. I thought they had become Mercedes and were powering the Brawns, Maclarens etc.
Ilmor have been making and doing most of the Merc engine design work for years......just dont tell the germans ;D ;D
-
With the middle cylinder being double the size as the outer two I would say its got the power of a V8 in a V6, there fore having less weight but more power, and its still 4 stroke.
-
With the middle cylinder being double the size as the outer two I would say its got the power of a V8 in a V6, there fore having less weight but more power, and its still 4 stroke.
Nope, definately 5 active strokes
-
Add a small injector to the centre cylinder and you have a 5 stroke with a 2 stroke booster stage.
-
in the middle cylinder its visible from the valve places 2 seperate strokes.. but cant see an angle difference for #1 and #3 :-/
anyway I'm not a mechanic.. ;D
-
in the middle cylinder its visible from the valve places 2 seperate strokes.. but cant see an angle difference for #1 and #3 :-/
anyway I'm not a mechanic.. ;D
1 and 3 fire 360 degrees crank rotation apart, so on alternate rotations. This is why they are in the same position on the crank, but their cam lobes are 180 degrees out.
Just like cylinders 1 and 4 on a GM V6 or 1 & 4 / 2 & 3 on a 4 pot.
I wonder how well balanced this engine would be? :-/
Kevin
-
in the middle cylinder its visible from the valve places 2 seperate strokes.. but cant see an angle difference for #1 and #3 :-/
anyway I'm not a mechanic.. ;D
1 and 3 fire 360 degrees crank rotation apart, so on alternate rotations. This is why they are in the same position on the crank, but their cam lobes are 180 degrees out.
Just like cylinders 1 and 4 on a GM V6 or 1 & 4 / 2 & 3 on a 4 pot.
I wonder how well balanced this engine would be? :-/
Kevin
Thanks Kevin... :y
its hard for me to understand this mechanic Hocus Pocus ;D ;D
-
I was right :y
Also it will be balanced if 2 weighs the same as 1 & 3 together.
Laverda have done 180 degree triples, but 120 is normally better.
-
[smiley=evil.gif] [smiley=evil.gif]
today printed the schema of the 5 stroke engine ..
and I made a quiz for my mechanic friends..
they just look :-? ;D ;D
and nobody answered correctly.. ;D