Opposite piston engines and Bill Gates

[micdhi]

Hello micdhi

Personally, I love this engine. I find it very well thought out and it seems to settle the defects of the 2-stroke engine.

I hope that thanks to Bill Gates's $$ he will put the 2 beats back on light (pun intended!) And will motivate the builders.

micdhi, on another subject, you told us about tests at Cemagref in November 2010. Can you tell us more?

Hello .
I believe in it as hard as iron, (although in reading the patents there are gaps but it is surely wanted)
Thank you for this sad reminder, but I postponed the meeting because I had a real trouble racing the pistons with risk of contact at the bottom of the cylinder head.
let me explain :
(first of all to understand it is necessary to know the plates / cams of the pumps, hydraulic motor with axial pistons)
on these, the tilting plate gives cubic capacity, BUT the pistons start at zero cubic capacity, IN the middle of the cylinder stroke.
for a tilt X the pistons go up on 180 degrees of rotation of the shaft, and go down on the other 180 degrees ......
but for a heat engine it is necessary (imperative) that the pistons always rise the same distance from the cylinder head ......
FOR MY ENGINE.
it has 2 plates / cam (one on each side behind each piston of the same cylinder) 1 plate takes care of three pistons.
but it is substantially identical to OPOC. them they have 2 double pistons opposite mine has: 2 opposite pistons face to face X 3 cylinders placed at 120 degrees parallel to the central shaft (120 ° seen at the end of the shaft), and the variation of displacement I make it in moving by 2 synchronized cylinders.
the plates / cam (moved by the cylinders) indeed to STAY with always a TDC identical if they move the pistons of 5 mm back from TDC, the inclination of the plate / cam makes 5 mm stack uphill ..... and so we have variable displacement for the OPOC. there is 5 + 5 mm of travel (for example) with 5 mm of rise and 5 mm of descent, always with an identical approach to TDC.
yes I know difficult to understand and I explain myself poorly.
my problem was that I moved 5mm (example) the chainrings while I moved 6mm (example) the pistons >> very serious problem between moving the chainring and tilting rod >>> a part to be redone.
of rage I stopped, then started again recently
cordially

[chatelot16]

I imagine your engine with an opposed piston controlled by an incinerated plate

don't call it aps OPOC oposed piston yes, oposed cylinder no, is in addition the oposed cylinder is absolutely useless in this opoc engine

the 2 cylinder would be in line the engine would be more compact!

by placing the articulation axis of your variable displacement in the right place, you can obtain a pmh independent of the displacement ... or even a pmh varying just as it should be for a constant compression ratio

but it is useless for a 2 stroke! if you reduce the race it doesn't open the lights anymore!

there is only 4 stroke or variable displacement is possible

with 2 crankshafts at both ends, it is possible to make a variable compression ratio by changing the phase shift between the 2 crankshafts

it can be used for variable overeating

at low power, large volumetric ratio, no overfeeding

at high power big supercharging and reduction of the volumetric ratio so as not to have too strong compression

It falls well it is when we increase the phase shift between the 2 crankshafts that we decrease the compression and that we optimize the scanning.

one more advantage for the 2 stroke 2 crankshaft

[oiseautempete]

Yes, but a crankshaft is the heavier moving part of an engine ... the Jumo diesel engine Junkers was at 2 crankshaft: economic certainly but by far the heavier of all the aircraft engines to pistons ...

[chatelot16]

there is a difference between crankshaft in cast iron gs of ordinary car and in steel with high resistance for flying machine

the junker jumo was designed in 1920 ... there has nevertheless been some progress since in steel available

same clerget began his studies some ten years after junker, so took advantage of better materials

and I punch: the total weight of 2 crankshafts or a single pass all the power will be of the same order

remains to compare the weight of the transmission between 2 crankshaft with the weight of the long connecting rod ... for me it's clear, single crankshaft and long connecting rod is for heavy and simple mechanics ... 2 crankshaft is for light and hi tech

it's not just the weight of the long connecting rods that counts, there is the increase in size that it entails and which costs weight in terms of the casing of the pipes and the rest

putting the cylinders in line gains weight by grouping together all the pipes, exhaust pipe intake pipe, injection cooling ...

the opoc engine removes the 2 cylinders without great advantage and wastes weight and volume in the piping

the height for the complexity of the piping is the star engine ... but at least we gain a good economy on the crankshaft ... although that remains to be proven: the crankshaft must have a counterweight of equal weight in total connecting rod and piston

with an in-line engine the piston movements naturally balance ... the counterweight of the crankshaft is much lighter

[Philippe Schutt]

because for some obvious reason, the exhaust lights are not cooled.

I do not see the obvious reason, nor that they are not cooled, or why it would be more problematic than for a valve.
For me the reason is different.

[oiseautempete]

the height for the complexity of the piping is the star engine ... but at least we gain a good economy on the crankshaft ... although that remains to be proven: the crankshaft must have a counterweight of equal weight in total connecting rod and piston

with an in-line engine the piston movements naturally balance ... the counterweight of the crankshaft is much lighter

The piping of a star engine is not more complicated than on another engine, on the other hand it is more difficult to manufacture and a little longer (the intake tubes of the cylinders meet at the level of the single carburetor and the exhaust manifolds are often grouped by 3 cylinders) which poses problems of regularity of richness from one cylinder to another, and makes starting more difficult (condensation of petrol when cold), but these problems were solved with the direct injection used on the last engines (on Superconstellation).
These engines are always lubricated by dry sump, but this is the case for most of the high power aircraft engines ...
The crankshaft despite, the heavy counterweight, is much lighter than on an in-line engine of equal power and also allows great torsional rigidity, very important on an engine which drives a propeller especially if it is direct (without reducer) .
The advantage of the star engine is its simplicity and ease of cooling (up to 18cyl because beyond this is no longer the case ...), the main drawback drag, but it is much less true on an engine without valves which has a much smaller diameter because of the flat heads as on an engine with side valves ...

The last R3350 with double stage centrifugal compressor, direct injection and turbo compound were quite supplied with pipes, but not because of the arrangement of the cylinders ... the fact remained that they were rather economical in terms of specific consumption (g / cv)
http://aviatechno.free.fr/constellation/moteurs.php

[micdhi]

because for some obvious reason, the exhaust lights are not cooled.

I do not see the obvious reason, nor that they are not cooled, or why it would be more problematic than for a valve.
For me the reason is different.

the essential reason is obviously, the compulsory mixture of oil and petrol for real 2-stroke. the others the semi 2 stroke (those with an exhaust valve and intake lights) do not have this problem of oil which escapes in nature, the opposite piston engines either;
but there are also 2 strokes >> combustion per revolution, the hot gas discharge surface must be the largest, because the displacement is double (for the same bore diameter compared to a conventional), but especially not with very high lights, (this overheats therefore significant expansion the little material on which the segments will circulate) and the outer part at this level of the lights is annular. without water or fins.
in your answer you are right, I only wanted to say that when there is no surplus of incoming fresh air which cools a little more, there is a risk of heating and deformation of the material at the level of the lights.
cordially

[Aumicron]

chatelot16 you are too critical of this OPOC engine. Analyze well the advantages compared to the old 2T and compared to the current 4T.

in addition the opposed cylinder are absolutely useless in this opoc engine

I think, on the contrary, they are definitely involved in getting a great sweep

and I punch: the total weight of 2 crankshafts or a single pass all the power will be the same

I think you are stubborn. Without being a specialist in rdm, the weight will be clearly higher with an increased complexity for their synchronization.

[micdhi]

I imagine your engine with opposite pistons controlled by 2 inclined plates

by placing the articulation axis of your variable displacement in the right place, you can obtain a TDC independent of the displacement ... or even a TDC varying just as it should be for a constant compression ratio.

but it is useless for a 2 stroke! if you reduce the stroke it doesn't open the lights anymore!
there is only 4 stroke or variable displacement is possible

good evening.
your second sentence matches exactly where I screwed up.
I wanted in addition to add a small mechanism controlled by a small cylinder, (a phase shift between displacement plate and tilting plate) of variation of the volumetric ratio (like the MCE5) whereas I could not have this modification and have a traditional engine but with opposite 2-stroke pistons.

sorry chatelot16 for not being able to say more about your last two sentences.
but I reduce the stroke without reducing the area of ​​the intake AND exhaust lights too much, and there are 2 times left.
try to have a good night
tomorrow i will try to show you by short drawing my error.
cordially

[Alain G]

micdhi

You just have to do like Rotax with the RAVE exhaust valve which works with the exhaust pressure to open!

http://saldman.tripod.com/Rave_valve/Rave.html