Installing free-valve technology on a Harbor Freight Engine

I don’t know enough and free valve tech…. But I do know there have been a lot of advancement from mistakes, ignorance and what if’s to just sit back and see instead of status quo and academics saying that’s idiotic.

Most really good invention happens by surprise, often when a meticulously planned test event goes sideways (US) / pear-shaped (UK) . See, you folks ARE teaching me something.

Ask me how I know. If you have time.

Vulcanized rubber comes to mind… even though they were experimenting with making rubber more usable… it was an accident that solve that problem.

Like P911, I'm ignorant (probably more so than he) regarding Free-Valve Technology, But I do have a few comments.

1. Why 59 magnets? If that toothed disk were steel, there are at least a few ways of using a single magnet to trigger the Hall-effect sensor. I suspect it wouldn't be long before at least one of those magnets goes flying off.

2. If he must use 59 magnets, then use rod-shaped ones fit into a series of 59 holes drilled parallel to the axis, and the holes would greatly reduce the probability of losing magnets.

3. Why use magnets/Hall-effect at all? The Omron™ EESX series of photo-interrupters can operate at guaranteed 1kHz and average 3kHz. They would work perfectly well with a thin black plastic toothed wheel, and I believe have a significantly faster rise and fall than Hall-effect sensors.

4. I rather suspect that his computer/program is what is limiting the speed. I didn't see what kind of microprocessor he was using, but for this job, it better be fast, and his program must be as simple as possible.

You’re just being modest… what he’s doing is proof of concept… but basically with those magnets what he did is created a type of encoder for a feed back system. Right?

Correct. It's an encoder. I should have mentioned that there are many kinds of Hall-effect sensors; some have vastly faster frequency response than others, and he needs a very fast one.

One reason I prefer optical sensors over magnetic sensors in non-enclosed configurations is the tendency of magnets to pick up miscellaneous small ferromagnetic bits. In his garage, I'm sure there are plenty of those floating around...

I agree with the optical sensors… less chance of of interference as well as the speed.

like I said earlier,… it’s proving proof of concept.

I missed his reasoning, I fear. It looks to me like he is pursuing it because he wants to use a "cheap" engine as a test bed for learning how to adapt the tech to bigger and better use. Always worthwhile. If you refer, though, to using Hall devices and electromagnets (or air, though I don't understand either the why or the how of that) in order to control valve operation, great. Being able to independently change lift, dwell, open and close slope over time, as well as when in the cycle each valve moves (allowing for selective overlap of opening, to better purge wastes, as well as delaying exhaust opening in certain circumstances, to allow for a longer power pulse) would be golden, especially if the parameters could be changed with a computer's speed and a sufficiently smart and adaptable software program. Shoot, using robust enough electromagnet drivers you could time valves in a heavy braking situation to create a custom and modifiable "Jake Brake" affect.

Overall, I don't know HIS reasoning (maybe he said it and I didn't get it) but any or all of those would serve as good enough reasoning to send me looking.

Yep. Occurred to me this morning, and he indirectly confirmed it by talking about using only about 6 pounds per valve spring for spring compression, but traditional mechanical valving uses (wastes) a large portion of the engine's power just actuating valves. Using Solenoids might not give 200k mile longevity, but if that starts us toward fully floating valves, the reduction in that power loss alone should drastically improve economy, also.

I think the spring tension has to do with speed of seating the valve in high RPM situations, it seems engine builders always go with stronger springs...having a piston hit a valve is game over I would think...still diesel engines work well at low RPM, but then they also have higher compression...maybe something in the middle...of course turbo charging the engine would have the same effect it seems....

....really good for a hybrid....

REALLY impressive Technology!

Thanks.