Normally when you think of a V8 engine you think of pistons driven by exploding fuel, pushing a crankshaft. [Miller’s Planet’s] version doesn’t use pistons, instead it uses solenoids along with a 3D printed crankshaft. The finished product would make a great science project or classroom demonstration of how a crankshaft converts a reciprocal linear motion into a rotary motion.
There are a lot of 3D printed parts and the links are in the post. A lot of the video (see below) is filmed in the wordless-workshop style with just a few text overlays to explain what is happening. But towards the middle, you’ll hear an explanation of how a solenoid produces force. The real payoff though is at the end, when you get to watch the contraption in motion.
There is a two-part commutator that looks as if it sequences the solenoids. There are some springs involved, but a diagram would have probably made this part clearer. Ignition sequencing wouldn’t be hard to do with an Arduino if you had output circuits that could handle the current of the coils. Most real engines with electronic ignition also have a crankshaft sensor to determine when the shaft makes a full revolution.
We’ve seen some similar builds in the past, and we’ve even seen them done with old hard drives. If you are wondering why you don’t see these actually being used, it is because of their super low efficiency. It takes a lot of input power relative to the output power you can obtain. If you prefer your pistons to be LED-based, you could always build a clock.