Compressed Air Engine V3

in three two one in the video and the top loaded last week I said the following so there's quite a few things I want to improve with the version one engine but the single most annoying thing with this engine is the piston or more specifically the piston spring I just hate this spring and then when the version two engine didn't work I said this and next week's video I will revert back to the version 1 piston with this spring and see how well that works but then just after I uploaded the video I thought to myself why on earth my going backwards so let me explain a few things using this very dirty white board these vocal lines represent the cylinder of the engine and the horizontal lines represent the crankcase now on the right side of the engine or the front of the engine there is a bearing this bearing supports the crankshaft and the con rod is then connected to the crankshaft then on the other end of the con rod is the piston this is a very basic drawing of the cylinder piston and bottom end of my 3d printed compressed air engine now being a compressed air engine it has to have some kind of compressed air inlet and previously I've been using a bull valve which acts as a cylinder head if you watched my older videos you'll see exactly how I open this valve it was usually done using a pin and a spring which would hold the bull open and sort of adjust the valve timing and it worked pretty well in my version one however ever since I designed that version one engine I've always wanted to build some kind of cam driven valve which is also driven by the crankshaft basically a valve that isn't open by the piston but instead a cabin push rod mechanism that is driven by the crankshaft now this supper design is obviously a lot more complex because I'd have to extend the crankshaft add another support bearing and then some kind of cam and push rod mechanism to open the ball valve and even if I can extend the crankshaft there's no way of getting the push rod to open the ball valve in the format of engine that is in currently another option is to use a slider valve where a plate with a hole is sandwiched between the bottle lid and the compressed air engine and the push rod will simply slide this plate up and down until the hole in the plate ends up with a hole in the lid and it lets the air through and as a pusher comes down the holes don't line up and the airflow stops now the issue with this design is trying to seal it properly essentially there could be upwards of 100 psi pushing on the left side of that plate and depending on the diameter of the hole the force will obviously vary however those to them to be some force coming from the right-hand side of the plate to keep the seal between the plate and the lid this becomes an issue when the plate needs to slide up and down because there will probably be some kind of rubber material between the plate in the lid causing a good seal however this will also produce a lot of friction making the plate hard to slide up and down which I think would just cause too much resistance for the engine to spin efficiently the only way I can see this slide valve working is if I have some kind of ball valve just in front of the slide valve this ball valve will hold the pressure into the bottle and prevent it from leaking out when I don't want the engine to run therefore the sealer on the slide valve probably wouldn't have to be as good allowing the friction to be reduced however that added complexity of these two valve systems is just a bit of a pain and I don't really want to go ahead with that so let's go back to the ball valve idea since it doesn't apply as much friction to the system but instead just requires a small impact force to open it if I were to move the ball valve above the push rod as shown here it would need a sideways force from the right to open it now this is obviously an issue because the push rod moves vertically and the ball valve has to move horizontally I can't think of a way of translating this push rod vertical movement to a horizontal movement while still keeping a good seal within the engine so I had to scrap that idea too but hang on what if I orientate the ball valve to be vertical like the version 1 but just offset it from the cylinder so it can be pushed up by the push rod allowing the air to flow through and into the cylinder I think this idea could work however I've also had another thought you see with this small volume off to the side of the cylinder any kind of air when the piston is at the highest point in its stroke is wasted air therefore I want this offset volume to be as small as possible which means compressing the engine in the horizontal axis and the issue with this is that I also have to compress the crank shaft but I have to quite large bearings in there and I can't really reduce the amount of thread on each bolt to connect the con rod to the crank shaft so here's my new idea a regular cylindrical piston has a slot cut out of it for the con rod to pivot inside this is that slot shown from the top view and then here it is shown from the side view now my idea to compressing the crank shaft is to use a square shaped piston this way the slot that the comb rod can pivot inside it can be offset from the center so let me redraw the engine and show you how this is going to work so here we have the cylinder and on the very right hand side we have a bear which is going to support the crankshaft and then at the very bottom is just the rest of the crankcase so here we have the square piston at the very bottom is the crankshaft now with the con rod offset from the center of the piston the crankshaft can be shifted slightly to the right so when I add the extension to the crankshaft on the other side of the con rod it can sit pretty much directly below the center of the piston this also allows the secondary support bearing to be shifted slightly to the right which means the cam on the end of the crankshaft can almost line up with the exterior of the cylinder so here you can see the push rod runs pretty much up the external of the cylinder and the volume at the very top of the cylinder is quite small so if this idea works not only does it increase the efficiency of the engine but it should also increase the size and the weight of it so let's get building and see if my idea works [Music] [Applause] [Music] so the version three compressed their engine is now ready for testing the propeller and piston move Nitin smoothly and if you look on the back side the cam and push rod seem to work quite nicely as well you may notice that this looks a bit odd it's almost like a cutout section and that's because I've designed a cover to go over the cam section however the tolerances weren't quite right in my dimensions and the head of the bolt rubs on the inside of the cover so I'm going to leave that off for testing you may also notice that there's some fiber tape at the top here when I designed this part of the cylinder I forgot to check on my 3d printers slicer but the wall on the back here is too thin and the slicin just said that the nozzle couldn't fill in that thin wall so there's a hole at the back however it's not under any really high pressure so that tape should just do the job most of the airflow will just be going into the cylinder to push the piston down so yeah let's give it a test let's screw it onto the bottle and give you some pressure so that's 30 psi just give it a test ready set go [Applause] how cool is that I'm really pleased of that the the time of the cam seems to work pretty well for the first attempt I'm not really sure whether I need to adjust the timing or not but the fact it works first tries is really impressive and also what I've just noticed is that the bottle is a very low pressure now I can squeeze the bottle so that means that this engine seems to run down to quite low pressure my gauge on my pump doesn't seem to go much below about 15 10 15 psi so it's not very accurate but I can tell us that's probably less than like 2 psi and the engine was just about running then so that's probably a good thing the version 1 engine never used to run probably below about 20 or 30 psi so the fact it runs at 30 and lower it's a good sign what I also noticed is that I started the engine with one finger and barely even a hard push so that means that the cam mechanism opens the valve quite easily which could possibly mean that it will run at much higher pressures in version 1 so if I can get this engine to run it a wider pressure range then it could be on to a winner let's do it again cover up the window not used to the Sun in the UK increase in depression out to 60 psi your ma be able to hear some air leaking but it's actually from this valve at the back the engine seems to be perfectly fine 3 2 1 [Applause] really really really pleased with that stop I still can't believe how well that works so there we have it the version 3 of the compressed air engine which is fully 3d printed out of PLA plastic I'm really happy with the way that this runs I'm sure it needs some tuning the cam of the crankshaft driven cam that pushes a push rod to open the ball valve where it's really nicely and the fact that he worked first try was well I'm really glad that it happened I'm sure I'm going to have to adjust the angle of phase of when it opens a mouth I might delay it slightly I think it might be opening a bit too early so I might just adjust the angle of it and possibly even the shape of the cam to maybe try hold the valve open a bit longer I don't know these are things I need to test out over the next week or so I'm really happy with the way the square piston design turned out as well it made it much easier to sound the piston and ascend into shape because you're just standing a flat surface rather than a a curved cylinder and also that it allows the whole engine to be compressed a bit because that the first bearing goes here and the second bearing goes underneath the piston so it really shortened the length of the engine so I guess the next step with this engine is to test it under high pressures see if the 3d printed lid can handle the load and that the new cam mechanism can still open the ball valve and as also mentioned need to experiment with different shape and angle of phase cams to see if I can make it a bit more powerful and possibly a bit more efficient I don't know yeah really happy with that and what's that thank you very much for watching if you enjoyed this video please give a thumbs up if you're new to my channel please click Subscribe and huge huge thanks to all my patrons you guys make these weekly videos possible and if you wish to support me on patreon please click this little box up here once again thank you very much for watching and I'll see you next week goodbye

Channel: Tom Stanton

Views: 1,750,550

Rating: 4.8733449 out of 5

Keywords: 3D print, 3D printer, 3D printed, DIY, PLA, Compressor, compressed, compressed air, compressed air engine, air engine, engine, piston, pneumatic engine, air, how it works, motor

Id: FoQUwpfFnnE

Length: 11min 39sec (699 seconds)

Published: Fri Apr 20 2018

Reddit Comments

[u/laskitude]

I thought it was a new Chi-Fi IEM!