Adventures In Deleting Camshafts | The Theory

[@WesleyKagan]

This is going to be a long project... But I'll keep you updated as it goes along! in the mean time, I have some fun projects going up in the next few weeks! Thanks to everyone for the support, You all are amazing.

[@nefariousyawn]

Forgive me if it was already mentioned and I missed it, but does adjusting the gear ratio between the stepper and the valve fix your speed problem?

[@sethlinerode1047]

Hey I just saw came across your channel and I have built a mechanical build I did but I abandoned it because of the tunning problem I don't know how to program things just mechanical things I am in Ohio I would love to see what you thought

[@gavnivag7436]

Use a odrive for the stepper replacement uses brushless dc motors and encoders. They are faster and higher torque but still takes step and direction commands.

[@Quindictive]

@@nefariousyawn I was wondering the same thing. It would increase the torque requirement, and also give less "resolution" in valve position.

[@MisFakapek]

Wesley but doesnt that make the actual design like 4x more complex and mechanically "vulnerable" than normal camshaft? One of the goals for freevalve was much more granular and flexible valve control. You could modulate rpms from low to really high. Any rotary electric drive would make it pretty rpm limited, so I would ask simple question: why not hydraulics? They are much more controllable than pneumatics and you can control them with common solenoids. True, you need high pressure system which introduce all of those nasty problems ... but ... they offer so much flexibility.

[@nottherealjk]

"Enough of me talking, let me talk some more..." I'm dying. You're like a just as smart and just as dry SuperFastMatt. I heartily approve.

[@a_Fax_Machine]

I really hope they collaborate on something some day. They have such a similar style, irreverent delivery, and scary levels of intellect

[@tkreitler]

Two of my favorite channels. I would like for Wesley to design the valves for SuperFastMatt's new land speed car or maybe the S600.

[@haroldthe_big_h117]

Nice work, I have done a bunch of thinking about doing this myself. A couple comments: I think your math is a bit off, in that the 20 ms you calculate is how long it takes for 2 crankshaft revolutions. The valve is going to have to open in a small fraction of that time, and get closed again also. I calculate 6000 RPM = 100 revs/sec = 36,000 crankshaft degrees per second. If you allow 90 crankshaft degrees for the valve to open, you only have 2.5 ms for the valve to open, not 20 ms. This makes your job a lot more difficult. You can make steppers go a lot faster by applying much higher voltage. The stepper torque is related to current, not voltage. The heat generated inside the stepper is also related to current, not voltage. You just need a lot more voltage to make the current through the inductance rise a lot faster. 200 volts or more is not out of line here. The stepper driver needs to regulate the current to the stepper winding. This is normal practice for any high-speed stepper application. But in my opinion, you are fighting a losing battle with mass. You have to accelerate and decelerate all the mass of the stepper rotor, gears, ball-screw, and valve etc every revolution of the engine. I believe the "best" (most likely to succeed) approach would be to use a voice-coil type actuator. Stationary permanent magnets, moving voice-coil connected to the valve. There is a reason that speakers are made this way. Large industrial vibration testing machines also work this way. I have an actuator from a _very_ old hard drive built like this: it has a 3" diameter voice coil, with a 30-lb magnet assembly. (This hard drive had two 17" platters...) You will still need a high driving voltage to overcome the inductance of the voice coil, but at least you will not have so much mass to throw around. Nice work, good luck!

[@turtleface166]

+1 for voice coil actuators. I worked on a medical product at work that used one in a precision motion application that was able to control the position of the coil down to the micron range while going through a set trajectory over and over and over at say 100Hz or so. The hardware was very straightforward - just a simple 24V full bridge driver. The control was the hard part, as always, but it was sick to see it work. Watching the actual position VS. The trajectory at those small time scales was cool! Fun project.

[@DiscoFang]

+2 on voice coils. Lets see a couple of mono block audio amplifiers strapped to the harbor freight motor.

[@martindinner3621]

So effectively a precision solenoid? Hmm, perhaps a fast solenoid/ voice coil with a stepper controlled depth/opening distance control?

[@matthiasmartin1975]

I concur. Those types of actuators get very expensive very fast though - see recent EEVBlog episode.

[@johnmurray9746]

Completely agree. I haven't done the calculations, but I find it highly unlikely that he'd be able to accelerate all of that mass fast enough with a reasonably sized stepper to make this design work. A voice coil seems like a much more viable option.

[@jarredquinlan187]

Loved the whiteboard presentation where the board was changing in the background, but there didn't appear to be cuts...that was clean.

[@chaseweeks2708]

Each episode his editing and framing skills are getting better in conjunction with the work that he's doing. It's awesome to witness.

[@timwatterson8060]

no cuts just edited in the content(from post or pre footage), look as the square around the content change shades of white.

[@NavyMitchell]

I came here just to comment on this. Really cool cuts.

[@Bashman1981]

Dude, I love what you're doing. Real innovation. However, please... there are times a pair of safety glasses is really a good idea. If you get hurt, all the crazy mad scientist stuff will stop, and we don't want that!

[@WesleyKagan]

I need to get better about it, I agree. luckily everything here was very sturdy.

[@Maxbeanbag]

100% agree Wesley. Put extra time into ensuring the longevity of that epic brain.

[@isthatasupra9569]

Bro don't worry he had his safety squints on

[@timplett1]

Perhaps purchase a Colin Furze safety tie as well

[@_Dan0saur_]

@@timplett1 this comment made my day bro😂😂

[@802Garage]

1:38 Is the best. "The bad news is that it doesn't work, but you don't know that yet." Then you laugh and have to cut. Different than anything I had thought of and super cool. Seems like it could be made robust and performant to me. I've come up with several unique designs, but obviously I'm not putting in the work, you are! Absolutely loving this.

[@speetnut]

I predict, after 2 years, Wesley will interate his design into a rotary engine. "No cam shafts" eventually leads to "no Pistons" 😂 excellent content as always.

[@dylanzrim3635]

You’re on to something, being able to seal off the ports electronically could really improve efficiency, and if it works? Rob dahm would probably be first in line

[@John-rw9bv]

The whole point of the rotary is that the piston is the camshaft/valve -_-

[@Flumphinator]

Wankels don’t have valves. They use the apex seals.

[@906MediaProductions]

@@Flumphinator boy do they ever use em.

[@breakfast7595]

@@906MediaProductions Right? I had a buddy who owned an RX and fucked the engine only a few months after rebuilding it, which he did when he bought it. It's a cool engine, but it belongs on a track, or as a weekend vehicle.

[@ldubois724]

You should look up linear actuators, in term of acceleration they are probably better than rotary actuators for this kind of application

[@Eduardo_Espinoza]

What did he used in the last one?

[@ldubois724]

@@Eduardo_Espinoza He used indirect rotary actuators. It was air actuated in the end but not good enough. That's why in this video he says he switched to direct drive

[@macoppy6571]

Linear actuators is what Koenigsegg uses. I believe Hyundai is also experimenting with linear actuators, and is primarily constrained by the cost of production.

[@scott7024]

@@macoppy6571 arent the pneumatic linear actuators though?

[@dylanzrim3635]

@@macoppy6571 the article I read said koenigseg used solenoids

[@davidkclayton]

some thoughts : make or acquire linear stepper actuators and connect directly to the top of valve stem. lose the valve springs. do not mimic a cam, the major advantage of what this design is complete control of the I/O flow through the combustion chamber. meaning: control engine speeds without a throttle (add fuel injection). control compression ratio. control EGR for lowering combustion chamber temp. just to name a few.🤓

[@rhydlew]

For Freevalve the other advantage was independent control of each valve, especially in a 4 valve per cylinder design. One exhaust valve goes through turbo, one doesn't. Allows variable boost control and wastegate electronically. Could also allow 5 stroke Atkinson by reopening an inlet valve for exhale-compress, which allows variable compression ratio

[@apalrd8588]

I think you need a lot more energy than you realize when fighting against the valve springs, so the electrical power requirements will be very high. It's still a good design, but getting rid of the valve springs will make it work at lower speeds (until the inertia of the valves and components is too high for the motors to accelerate). This is why you tend to see more hydraulic systems in production (things like MultiAir)

[@elmauto3021]

Instead of rotating, try coils like a rail gun or voice coil in a speaker. Make the valve stem a coil with a coil around it, lots of power, speed and control

[@marcogiardiello2056]

Christian Von Koenigsegg has patents on the idea already. Be careful he is letigious as hell. Called FREEVALVE

[@pauljs75]

Hmmm... Can you use an induction coil as part of the solenoid plunger to boost it's reaction to a driving coil? That might be a way to get around curie temperature issues with permanent magnets or ferrous materials. That might be an interesting trick to having a strong linear solenoid action at the temperatures not uncommon to an internal combustion engine. That would involve re-inventing the linear actuator solenoid itself rather than trying to use something more off-the-shelf.

[@jackr1110]

This makes the most sense turn the valve steam into the linear actuating coil which is what Koenigsegg does pretty much

[@Drunken_Hamster]

Voice coils are incredibly electrically inefficient. To the point that there was a man who designed a servo-controlled subwoofer that delivered 10x the force on the same power as a 300w sub.

[@Pengajim]

I love that nobody’s perfect poster in your garage!

[@AtimatikArmy]

Just brainstorming here, but what about changing the valve system completely to say a rotary valve? Then you would get rid of the reciprocating action entirely which appears to be the main issue and I believe even in the best circumstance it will never be ideal.

[@DevinFriske]

+1 rotary valve concept Really neat idea, but implementing it is not something I can fathom from my armchair. I have the basic idea in my head but I have no idea if it would work in reality.

[@troywebb9223]

@@DevinFriske second the rotary valve idea. As the crank turns the valves need to open. Instead of "reversing the direction" every cycle why not implement a VTEC style actuator? The amount of lift could be changed over the course of a few crank rotations which in the end have a net similar effect. Electronic valves or cam-less 4 stroke.

[@zaucy_]

Dude your PC build is so freaking cool. What an awesome idea doing it on the wall like that and having each component almost like it's on display. Then running you custom water cooling system all through everything just makes it all look like some evil scientist's PC for his laboratory. Love it. Also, love everything else that you do as well. Such an interestingly awesome channel.

[@dangale6969]

Looking forward to it mate! 👌 been watching from the start of your channel! You’re amazing and inspiring for all

[@WesleyKagan]

Thanks a ton!

[@OMGWTFBBQSHEEP]

Great vid, i like this freevalve series! One thing about the acceleration, if you haven't thought of it already. If you can get ahold of the rotational inertia of the suitable stepper motor, you can use newtons second law and calculate the acceleration of the entire system, including stepper motor, gears, shafts etc. Then you will know if the stepper motor is able to accelerate the system quick enough or not :)

[@WesleyKagan]

That's absolutely true- It would cut down on testing things as I go. Good thought.

[@deathcogunit106]

Oh hell yes! This is easily one of my favorite channels.

[@WesleyKagan]

Thank you! Glad to hear it!

[@Byefriendo]

Ive been tinkering with something similar, I also first had the idea of a direct steeper actuated valve but came to the same conclusion you did. What I came up with was using an electromagnet/solenoid for actuation, but to achieve the variable lift portion, using a mechanical endstop that gets moved by a stepper via a threaded shaft. Normal steppers can be used and can change the lift by about 10mm in 250~ms which is very reasonable

[@jaredharvey1511]

Wall color is great. Have you happened upon rusEFI? That's a similar color scheme. Air actuators are typically fast. Either that or perhaps have a spinning motor then transfer the energy with an AC compressor clutch. If you are looking for electrical drive, a DC servo is your friend.

[@shakeorefined2514]

"So, enough of me talking. Let me talk some more." You speak my mind, my friend.

[@WesleyKagan]

I just know because I edit so many weird rambles out of these videos- There's probably 2 hours edited down here haha

[@davidelang]

(also sent via patreon) Simplify the task, convert to running from steam/pressurized gas That lowers your temps, and allows you to lower your RPM making it much easier/cheaper to build something that will work, allowing you to experiment more. external combustion engine would also let you go to 2 stroke vs 4 (more power for the same size engine), and adjusting the intake valve timing to change the expansion ratio as your throttle will really show the power of computer controlled valves

[@camillosteuss]

Dont just leave it there, give us more content buddy! This, you, the complex that is your thinking is a great thing and you should do what you do and display it, its a great thing for mankind, not necessarily a change, but a step that with its momentum might accelerate others in making more momentum of their own toward the grand change... I will try to get my shit together, as i too have my own projects and ideas that might aid the man, but for now, i have to get some shit sorted before i can film any of my thoughts and projects...

[@DiscoFang]

The problem of necessary inertia of a motor strong enough to do the job fast enough was my initial reaction to the 3d model. Related to your calcs - the valve opens & closes muuuuuch faster than 1 whole revolution.

[@ferrumignis]

Exactly this, and for the best volumetric efficiency you want the valve to open and shut as fast as possible. This will become especially important when you consider valve overlap which will need to be well controlled .

[@mikiemojo]

I really love your wall mounted computer. I wish I had one.

[@S9l8m]

I cannot say enough how enjoyable your videos are! I started following your channel a few months ago and every time I watch there is a noticeable improvement in video quality and the projects keep getting more and more badass! You say all the time “I’m not an engineer” but I can promise you that many engineers are applauding your work and innovation! Keep it up!

[@dusty_bike]

You could change the ball bearing guides to be non linear, Low pitch to overcome the high opening torque transitioning into higher pitch to get the valve open in time. Also if you havent allredy you need to re-make Bose active suspension

[@mushroomglue3249]

Have you considered looking at an ODrive (or similar) setup? basically runs a hobby BLDC motor + encoder as a servomotor; should allow for a bit more speed. I know there's a few people doing high-speed 3d printing using ODrives atm, kinda similar sorts of high-speed movements.

[@WesleyKagan]

I haven't heard of them before today but I'm going to order one just to see. Would be handy to have around for sure.

[@sacrificialrubber779]

Have you heard or thought about rotary valves? The experiment with them on a small block Chevy I believe…check it out. It might be a new direction to explore

[@hydrotricine]

Please dont give up on this project,what you are doing is fantastic!

[@WesleyKagan]

Thank you!

[@MrLordZenki]

The most incredible part of the video is how you managed to fight the urge to stop and love that adorable cat 😻

[@christopherferrante5689]

Love the project! What about a gearing the output of the stepper motor so the stepper spins once and the valve spins twice. (just some gear ratio) Surely it has to be easier to find a higher torque stepper motor rather than a faster one.

[@Aheitchoo]

This was my thought as well, although you could also change the gear ratio with the ball bearing slot helix angle.

[@ehb403]

Just a quick note on valve actuating times: you calculate 20 msec per revolution (at 6,000 rpm). This includes things other than valve operation, like compression and intake for the intake valve (the valve should "dwell" at the ends of its operation). Camshafts typically are designed to have a "duration" of about 240 degrees or less (not the 360 you calculated); keep in mind this time also has to include operation in both directions. So, 1/2 of 2/3 of 20 msec or less than 7 msec per "stroke" and the mechanical direction-switching action usually will take up some of this as well. Of course, you can gain time by reducing your maximum rpm (probably a good idea with the Harbor Freight engine anyway). Keep thinking happy thoughts!

[@onefastgmc]

Once someone figures this out and it's released to the aftermarket, the possibilities are endless. You can go from a nice smooth "cam profile" to a high lift high duration profile by basically coding it into your tuning software so long as your piston to valve clearance is good and the springs you're using don't see any bind. That's what you'll have to watch, it'll be cool to see it work but there are more tolerances in the engine allowing this to function than just opening and closing the valves at the right time. Super exciting though!

[@fredblase5608]

Wesley you are not thinking from the ground up, rather from the clouds down! My humble thoughts are to use air cylinders to open the valves and a tapered rail with a stepper motor to locate the rail and control lift. Air pressure could be controlled somewhat limiting lift also, Air hammer to push open the valve and a suitable spring to close it,or possibly an air cylinder around the valve stem along with a lite spring to close the valve.Air pressure could also be controlled on the closing side independently from the opening side. A lot of words I know , drawing a picture would be simpler but above my abilities on a computer. Anyway Keep up the project , as one comment was made , "Rome was not built in a day, they have been working on it for CENTURIES!!!" and still at it !Thanks keep up the good work Fred.

[@M_Gargantua]

I love the idea of the ball bearing rotation design. One thing you might be able to experiment with, since at high RPM you aren't really ever going to want to adjust valve lift (it will just be max lift above some rpm threshold), you could do a continuous bearing race, and control duration by slowing a continuous single direction spin rather than reversing, where at low RPM you can easily adjust lift by reversing. You can also improve performance with a servo motor (or just a 24Vdc motor with a rotary encoder slapped onto your design), since you don't need exact positioning anymore, just good position with good torque. If you want extra resolution on the "cam" sync position go with a little Pogo pin to ground a sensing pad when the valve reaches the top of its stroke.

[@urbanmattias]

Just my thought as well!

[@curator23]

Ball screw vs rack and pinion? Use servos instead of steppers? They typically out perform an equivalent sized stepper. My approach to this would have been to develop a linear servo using a long throw sub woofer driver and amplifier as a basis, modify the amp to use a hall sensor for position feedback.

[@gIeener]

Last place I expected to find the cover of Twin Fantasy, but a welcome one. Good choice!

[@theleadfootgunner6804]

Absolutely love seeing your videos pop up on my feed. I’ve never seen someone so smart, be so sarcastic with themselves LOL. Keep your insanely erratic brilliance cranking out ideas!!

[@Scrogan]

Use brushless servos, or just common brushless motors with an encoder on each. Also I think you could get electromagnets to be fast enough if you overvolt them initially to get the current up quickly. Maybe have two FETs on each electromagnet, one that gives it the full voltage, and the other that gives it a lower voltage. Using a weak spring on each valve would let you open it quicker, so long as you forced it closed by putting the electromagnet into reverse. I think you could reduce electricity consumption by having the electromagnets feed their energy back into the battery+capacitors via H-bridge control, which may or may not be possible. Great project man.

[@ugagnskraake]

I really admire your abilities to conceptualize and implement mechanical solutions. I'm a 30 year old embedded software engineer teaching myself mechanical engineering to hopefully become as skilled as you are one day.

[@DatBoiOrly]

i honestly don't see a problem with re-inventing the wheel because as a collective if multiple people work on the same idea and try to improve it by doing it there own way its gonna cause innovation in the original design. not only that your creations are unique in nature making them entertaining to watch not to mention sharing your knowledge and failures so were learning along with you i hope you keep posting on this cam free engines

[@WesleyKagan]

Thanks! I appreciate the kind words.

[@soodonym]

Just a thought... Make a rotating valve rather than an in/out valve. Like a sleeve valve arrangement but within the cylinder head.... As I say... Just a thought that came to me. Love your work, keep it up

[@Byefriendo]

The valves in 4 stroke motors are a pretty important part in their performance, the valve sticking out in the air stream creates tumble which helps homogenize the charge mixture. Rotary valves would work and be easier, but would negate a lot of the benefits

[@theafro]

Engineering is the art of making the thing that you need, from stuff you can get. You missed on both counts! (But I love it, DO NOT STOP!) Balls may be a bad idea in the screw-jack thingys, they're going to generate radial forces that can only jam things up, cylindrical pins or small roller bearings running in flat tracks would mean the only forces generated would be axial and rotational, (also easier to make, and make reliably). It's also worth looking into higher voltages for driving the motors, you may have already considered this, but do not arbitrarily limit yourself to 24v, IR2 is a thing! Loving the projects dude, it's like my school-boy notebook, but on youtube!

[@nogood_ideas]

I am really excited to see what you come up with, I have been interested in camless engines for a while now. After watching the math portion and reading some comments, I have been trying to work some things out in my head. I'm not sure if my logic is right, but here goes. I guess the ultimate goal of this would be to achieve full lift of the valve quicker than a camshaft, so that the duration of the valve opening can be controlled to gain better performance from the engine. In a mild camshaft for an old school v8, most of the modern grinds seem to usually end up around 270-280 degrees advertised degrees of crankshaft duration. If we use 274 degrees as an example that means the valve isn't fully opened until around 137 crankshaft degrees (assuming a steady ramp rate and symmetrical lobes). At 6000 RPM that means the valve will be fully open in ~3.8 ms, and only gets faster as rpms increase. There seems to be many different ways to look at this situation. You could calculate the effective "advertised duration" based on 0 dwell at max lift, the time to fully open and close the valve, and engine RPM. You could also calculate the max RPM based on valve opening and closing time, where you run out of time to dwell the valve at that desired lift. I vaguely remember you mentioning something about a desmodromic valve system in your previous videos and not using one for a certain reason, but I'm not seeing the advantage of the ball screw unless it is easier to find something faster acting and with enough power in an electric/stepper motor vs. solenoid/some sort of linear motion device. I'm not very knowledgeable on the electrical side of things as a more mechanically inclined person, but maybe using a brushless motor could be faster than a stepper motor? You might end up needing to really beef up the stopping mechanism on the ball screw shaft, and you would probably lose control over fine valve lift adjustments, but it might be able to open the valve quicker.

[@lawrences1347]

What if your ball-bearing channels ran the full circumference of the valve. So the valve opens and closes as it spins. Then you don't need a stepper motor, you can use a more standard motor and match the speed to the desired cam profile?

[@rjk7104]

So just like a windshield wiper where the motor never actually reverses. Ought to be much easier to develop a PID loop for if you had direct feedback for valve position, which would remove the need to tune for different cylinder pressures under different load conditions.

[@alessiocarlevaro6934]

that would work just like normal cams do, he's trying to have different ramps, duration and lift depending on the load on the engine

[@WesleyKagan]

I did a design like this off camera, and actually used a second stepper to change the profile as it went around, but it limited the actual adjustment to around 10 degrees.

[@lawrences1347]

@@alessiocarlevaro6934 Yeah true, I guess it would be more like variable valve timing with a huge range than a total free valve.

[@ThomasFlemingOriginal]

Came here to say this. Using an angled race, valve open and close durations could be changed by just changing motor speed. No stepper required. Might not even need a spring (or at least just a small one) to close the valve.

[@Garbasker]

Fascinating as always, I love hearing about the technical aspects even though some of it maybe a bit over my head.

[@WesleyKagan]

Thank you!

[@dylanzrim3635]

@@WesleyKagan I was expecting “most of it goes over my head too” 😂

[@chopper3lw]

When you originally said you were going to try steppers in the last video my immediate thought was "it'll never be fast enough." I didn't comment because too many youtube ppl get negative comments. TBH I really think you need to use solenoids. Maybe steal one out of a starter motor. It'll require a lot of current, and to get precise control over it some tricky mosfet pwm circuit. Negative side would be that you'll have to deal with a spring again unless you do a pushme-pullyou setup (complex). Oh well, I can't wait to see this work as you desire.

[@WesleyKagan]

The only problem with a big solenoid is the inductance of the coil. It takes so long for the coil to discharge it can't charge up fast enough.

[@chopper3lw]

@@WesleyKagan Yea @5000RPM that'd be about 80Hz. You'd probably have to wind your own to get something fast enough.

[@DiscoFang]

@@WesleyKagan Car subwoofers seem to manage to operate fast enough at very high amplitude. Plus, rotary woofers use the voicecoil technology to operate an actuator at the required frequency.

[@dukiemoto8676]

Great! Can’t wait to see the progression of this concept. Keep up the good work

[@WesleyKagan]

Thanks! Will do!

[@phillglasson6357]

Hi Wesley, I know it's not in the spirit of poppet free-valve, but have you considered a rotating ball with ports through it? There might be opportunity to reduce the accel/deccel of poppet valve timing , to something less with a constantly rotating ported ball valve arrangement.

[@jetix4531]

Hi, A little suggestion/idea: instead of changing the gear ratio you can just adjust the shape of your ball bearing guides on your center pinion. Thank you for your videos, it is always very interesting.

[@Akya2120]

Yes, but the more aggressive the slot profile, the more aggressive the wear pattern.

[@wimvanderschelden1369]

Being able to follow the process of this project like this is awesome. It's great to see why this stuff isn't easy and what particular details are a consideration in something like this.

[@WesleyKagan]

Yeah, I'm trying to open up my process a bit more, and it's cool to document what works and not. Something something Rome wasn't built in a day. Not saying niche valve tech is Rome, but.

[@Drunken_Hamster]

In learning about rotary valves recently, I strongly suggest looking into deleting poppet valves in addition to camshafts.

[@jakeburch9705]

Wesley. I love your engine projects. This is very similar to what I want to do in life and I value your videos. Great inspiration man

[@Mrcrowntown]

Stock miata head for consistent location and oiling, and change the stepper ratio to something that gives you a coarse control resolution, but with a fast opening speed. It's a sacrifice in the beginning, but the raw data can only assist in the refinement process. Excited to see where this goes!

[@crudboy12]

It's been a while since I watched the old free valve videos but is there some reason why you have discounted electronic solenoids? It could potentially move very quickly, at the penalty of being essentially binary, (can't control exact position, it's on or off), but thinking about it, you could have a stepper motor adjust how much throw the solenoid has available to it, (by moving a stop) since these adjustments would only have to happen a few times a second and not 50+ times a second. You could also use one stepper motor for an entire head to adjust how far it opens.

[@RCapricot]

This is exactly what I was thinking! Electric solenoids seem to be the ideal choice here.

[@turkeyboyjh1]

You should look at how 2 stroke oil injection pumps move, you could use smaller steppers geared over out of the way for space and have linear actuators to change lift and slow and speed up the motors during constant rotation to adjust valve timing, the piston in those pumps are adjustable travel by an arm that connects from the throttle to the offset ball bearing cam and the piston that would actuate the valve in this case has an eccentric face on the top and it doesn’t rotate so the piston goes upon and down a little bit and when the motor and brought down valve lift increases

[@timwatterson8060]

look at trinamic enabled bldc motors in stepper Nema packages, stepper control with bldc speeds. Some other companies offer similar products with differing specs. You could also tune the ball race for the forces needed. It looks like your race design requires alteration of the steppers' direction every half cycle, and the associated acceleration and deceleration. If the race is made to always operate in one direction with known flats as needed, the acceleration and deceleration only need to be appropriate for the chosen flat lengths and open/close durations.

[@edh7492]

Some people are on a different planet, in a very good way. You are one of those people and it’s mind bending to observe. 🤜🤛

[@solenskinerable]

something cool you could try would be to drive camshaft with a strong stepper. you can modulate rotational speed by a sine wave to control how long or short the valve is open. going ducati style lifters would reduce imaginary load, too, and let a smaller stepper drive it fine.

[@rthomp03]

Would it be easier to find a smaller, faster-acting stepper motor, and connect them in series to the same shaft to meet the torque requirements? It seems like the response time is the limiting factor. Also, I'm not sure your calculations are correct, because during the compression and power strokes, neither valve is moving. So the time of the intake and exhaust strokes is still going to be the duration of 1/2 a revolution, and that's the time you have to open AND close the valve, including any duration you want it full open. 6000 RPM = 100 rev/sec. 1 revolution = 0.01sec. 1/2 revolution = 5ms (that's the entire duration of each stroke). So basically you're looking at around 2ms to open, 1ms hold open, then 2ms to close (depending on how much air you want to let in and out of the cylinder per stroke). You'll be hard-pressed to find any non-camshaft system that responds that quickly, and you'll have very little granularity for tuning.

[@unkleknuckles]

Crazy thought, a rotary valve, if you don't mind designing an entirely new head.

[@gigigigiontis8]

Rotary valves would introduce a LOT of extra problems

[@badatengineering]

Awesome Project!! About the motors you might want to look in to Odrive its a controller for BLDC motors that you can use them like a servo motor maybe that is fast enough, I am not sure though.

[@WesleyKagan]

Thanks for the tip, I'll look into it!

[@Pilotman28]

I really love your ideas and execution. You’re a mechanically inclined nerd which I also appreciate. I’m looking forward to the journey.

[@sevensixtwo5001]

+1 awesome points for being a Twin Fantasy enjoyer. As if you didn't have enough already.

[@sausagedog52]

you should make it so one full revolution is both open and then back to closed, so the stepper never has to accelerate, decelerate, stop, then accelerate in the opposite direction. this would come with the downside of no variable lift but it would allow for variable duration

[@alphawolf4714]

As a technician and sports car enthusiast, I'm rooting for your advancement and success. I want so badly to add freevalve to my V6 and get truly free and unlimited valve variation... both for fuel economy AND sorts application.

[@WesleyKagan]

I'm really pursuing this form, I'm a lot happier with it so far compared to the compressed air system

[@otterconnor942]

I work on aircraft neumatic valves. You could use faster motors with a mechanical stop switches to stop over travel, but the circuitry is a little bit more complex. Just a thought

[@-Just_Justin-]

It's great to see you back onto this project once more. I think as with your last decision the harbor freight and miata engines would be best suited for testing. I'm excited to see that you have managed to deal away with alot of components in the previous design to make it more simplistic. I'm sure that you will come up with a good solution.

[@stevesloan6775]

Defiantly recycle forged parts where you can. Home heat treating for the win!

[@rlpederson]

I've got an L-24 straight 6 block down here in Tucson, if'n you want to try it. Thats out of a 240Z, stupid simple bullet proof engine with an overhead cam. I would love to see a working free valve system for that engine.

[@ikocheratcr]

Maybe use two motors per valve, I know more complex design, but maybe easier in the long term. My idea goes as follows: One motor brushless DC ( 2 or 3 phase) that rotates the actuator you show in this video, but the thread path is not linear, it is more to the profile of open for a little time that a valve normally does. The second motor might be an stepper, the rotates an external cylinder of the actuator the first motor rotates. This cylinder has in the inside the balls the first one rides on, and external a fine pitched thread. The block that keeps this in place has the mating thread of this second part. The way it works, the brushless motor rotates at the right speed and phase to open and close the valve when needed. To control how much the valve opens, the stepper raises or lowers the fine thread cylinder and controls that. I know it is way more complex mechanically, but the brushless motor speed and phase control is not that complex, and the stepper handles the valve travel distance with not much torque. I do see one disadvantage, which is as more valve travel is needed, the amount of time the valve is open increases. Not sure how to deal with this. Changing the speed of the brushless per degree of rotation is not simple (inertia gets in the way). Hope you see this.

[@DrieStone]

A few questions: Would it be beneficial if you had preset valve heights? Maybe instead of having 0-100, you look at two or three profiles that you would be restricted to. Maybe then you can go with a solenoid design to rotate the "pushrod". Can you find push/pull solenoids that act quickly enough? You could use a stepper to change the linkage so that the solenoid rotates the pushrod more or less. After all, you don't really need the granularity of the stepper anyway. You want to open and close that valve as fast as possible. I also wonder if you should add a spring to the top of your pushrod to offset the force of the valve spring. I may allow your assembly to turn easier/faster.

[@DrieStone]

Thought about this a bit more. Is there a reason you’d want to change the per-valve height? Wouldn’t you change the valve opening for all the valves to be the same (obviously separate for ex/in)? I feel like you might be limiting yourself in the choice of a servo like motor. Could a standard motor without a stepper do what you wanted?

[@anidiotinaracingcar]

Can you use two (or more) steppers per valve ? To increase torque if you change your gear ratio There are also these weird drive systems that add the speeds rather than torque

[@pepethefrog7193]

Start and stop the stepper 50 times per second wont work. But you can let it run at 3000 rpm and control the rotation speed during the valve open and valve close parts of one revolution. Means you can control the valve timing with a stepper driven cam lobe. Tom Stanton does control a helicopter with this angular velocity system. See YT "Drone Helicopter Hybrid". Note that brushless motors are basically 3-coil stepper motors.

[@peternonsens4345]

Wouldn't it be easier to do a continuous track around your actuators and control the timing and lift with the rpm of the steppers?

[@webbeddizzy]

I have been wanting to do this ever since I first heard about what Koenigsegg did with the free value system. You are doing great and I love the experimental mind set that you have of figuring out what works and what doesn’t work. I think in your first video you mentioned electromagnetic actuators as a possibility. I would definitely look into those to see if they are a viable and affordable option. The stepper motors are a great idea but I believe there is still the mechanical component there in this assembly, that will wear out and eventually break. I believe that was a big reason for doing away with the cam and chain assembly. Also for your intake and exhaust timing having you to thought about “probing” the ignition timing to get your electrical signal for the actuators. It’s seems to my understanding that you are just setting the intake and exhaust timing to a constant but in actually it over the rev range of the motor. Please don’t think I’m being critical of you, I love what you are doing. These are just suggestions, can’t wait for more content!

[@Greeninja13]

An energized stepper motor should have enough holding force to seal the head. Get rid of the valve springs and see how much torque you need to open the valves (very little). Maybe use a small spring to prevent engine failure due to a bad stepper motor.

[@rikishi273]

Cool video - I like the idea - it feels like it could work without some super special motors and I couldn't help but also think about how I would try fix some of these problems: 1. Gear the connection to the valves so it is not 1:1 and less steps per open/close. less torque but it looks like you have excess anyway 2. Change the shape of the ball bearing cut-outs - I'm thinking a continuous sine wave pattern all the way around which connects to itself. You could even make this sine shape with flat areas at the peaks of the sine wave so you can keep the valves closed while still rotating the motor slowly and reducing the need for such high acceleration on the motor 3. less travel on the valves from open to close state - maybe you might have to put higher pressure into the fuel for this I'm keen to see what you come up with

[@Dont_Gnaw_on_the_Kitty_1]

How about using an actual on/off solenoid connected to a bellcrank lever that pushes on the existing poppet valve. Mount the solenoid on a movable plate and use a stepper to move the plate closer or further away. The lever gains lift the further it is from the valve.

[@linusgk5042]

You have become a lot better youtuber since I started watching you. I have extremely low knowledge and experience with electro mechanics. But have you thought about using an Odrive on a regular Bldc motor (most likely with a gearbox)? I know it have a big community that might can help you. Also, you have a dead fan on your top radiator on your wall pc.

[@bradley3549]

Since this is the internet I'm going to comment before even watching the rest of the video. The first concern I have with this design is that it requires the stepper to reciprocate. It has to accelerate, decelerate, reverse rotation, rinse and repeat. I see this being a serious limitation and I don't think you'll find a part that can do this. Seems like servo that can rotate continuously on a sort of crankshaft (to allow deleting the spring) along with a stepper to adjust total lift would be the closest you'd be able to get with off the shelf parts. Just back of the napkin.

[@darkevilapie]

a gearpump pumping oil in a loop and open and close valves on tiny pistons. might need some relief valves to mitigate liquid hammer. but in theory it should be fast enough and strong enough while beeing pretty compact. the oil should flow pretty fast in the loop so the valves can open and close in an instance. a buffer or accumulator might prove usefull.

[@davidfarmer]

The ideal motors would probably be brushless dc with magnetic encoder feedback. you also want to be careful with the mass of the ball screw, and to make it efficient and not bind, multiple races would be advisable. all this being said the best bet may actually be a solenoid. I know its also possible to make a solenoid with multiple poles that can act like a linear stepper. a stepper solenoid if you will.

[@MrBubmer]

I don't have anywhere I could do this, so I live vicariously through Wesley's videos

[@WesleyKagan]

I appreciate you watching!

[@alecweinstein4990]

You've got this "engineer left alone too long" humor and crazy ideas. This channel is almost singlehandedly getting me back into the mechE degree I've been burning out on. Remind me to buy you a tank of the high grade gas if I ever meet you.

[@SB-nr1dz]

Two thoughts. Could you cut a motor in half and have the rotor spin back and forth 180 deleting the gears? It would need to be a skinny rotor. Second thought, could the motor also have the fore/aft motion built in, like ready-rod with magnets attached....

[@charlescordiez6852]

Regarding your stepper issue, the choice of a stepper might not be the best in your use case. Off the shelf servo motor will have the accuracy and speed you need. Another option might be bldc hobby motors with reduction (planetary, cycloidal, strain drive ...) and use of positional control board like odrive or tinymovr.

[@WesleyKagan]

Yeah, servos seem to be a good option as well, I'm looking into a few.

[@grantbierlmeier7641]

I have a concept for the valves that probably won’t work. But. Instead of the traditional valve that has a stem and move up and down, what if you had a disc with a slot in it that rotates to open? It’s probably been thought of before and there are reasons it doesn’t work but seems to me you could get better flow and control with a disc than a stemmed valve. Like I said - just a thought. I lack the skills to try this idea out.

[@benjamindavidson632]

What about an cam driven oil pump. Since you already have a oil system to tap into, or it could be a stand alone system. After oil pressure actuation of the valve it could bleed off a bit lubricating the system. I know you want to use electronics but just an idea.

[@vardfriki7274]

Like banks only linear rather than rotary. High pressure low volume oil with electronic super low mass solenoid valves? Pretty sure catapillar deisel injectors work the same way too.

[@vardfriki7274]

Vanos not banks! Bloody spell check!

[@paramax55]

Have you thought of using rotary valves? Take a look at a french horn. They use rotary valves. They take almost no effort to open and close and their motion is already in the same plane as the stepper motors.

[@AmaroqStarwind]

Don't use ball screws without a Wobble Wing! (A very simple device that counteracts ballscrew wobble.) Also, servo motors (or perhaps torque motors) with an O-Drive are probably the way to go for both speed and precision. They can be pretty pricey though... To offset the acceleration problems, a variable gear ratio (of some kind) may help.

[@psychosis7325]

They keep blocking my comments trying to explain in full.... Math for 300 degree camshaft at 6000rpm is 0.0083 seconds to open, can not have too much overlap. Love the project, keep it up

[@atlasgames4275]

I think you'll need to change your thread design to make it so during a singular rotation it goes up and down otherwise its inertia will be far to great for any stepper motor to overcome.

[@KrisCroaker]

Have you considered doing a Diesel engine for you test bed? They operate at lower RPM ranges which could help with stepper motor requirements

[@fixyourautomobile]

Did you ever think about using the pressure from the engines oil pump in some sort of accumulator to drive a hydraulic circuit to open and close the valves? A factory oil pump will not flow enough, but a dry sump assembly could power some super high pressure hydraulics. and solenoids are FAST....

[@WesleyKagan]

Non compressible fluids are a lot nicer to work with, so Maybe. But oil is a lot more viscous so the pressure would need to be a lot higher. It's something to consider.

[@martinw6297]

Maybe look into the ODrive project. May solve the stepper problem. BLDC motors have much more power density.

[@BikeFromTheBrink]

I'm glad you've come back to this as it is what brought me to your channel in the first place. Have you considered a lotus style rotary valve which is stepper controlled. You could speed up and slow down each valve individually.

[@samuie2]

Love this project and that you share all the information. Would brushless DC motors with an encoder offer better response time? Controllers like O-drive even have "stepping" modes so the coding should be about the same. Plus being closed loop might be good for reliability.

[@nochan99]

Suggestion; why not wind your own motor? You can calculate the windings to spec, and the motor doesn't even need to be able to rotate 360, so you can probably save a lot of weight. (or wind it like a progressive solenoid contraption).

[@jasonblair8189]

Have you considered using brushless bldc motors with senses and a gear reduction. They might be able to reach the tuque and speed required