No crankshaft, no problem.

[PA.]

Copied from a automotive website.

 

Toyota's free piston engine is brilliant.

 

Let's get one thing straight: The variable-valve-timing, direct-injection, turbo-wonderful power plant in your new car is not cutting-edge. Despite the complexity of the modern engine, the fundamentals haven't changed since Grover Cleveland was in office. Pistons turn a crankshaft that eventually spins your car's wheels.

 

Yawn.

 

Electrically driven cars are the future. But until we have cheap, 1000-mile batteries, we still need range-extending fossil-fuel engines. Those devices don't need to turn wheels, just generate juice. The simple solution is to strap a generator to a piston engine, as BMW did with the two-cylinder range extender in its i3 EV. But if the engine never turns a wheel, there's no need for it to rotate anything. Why not cut out the middleman and use the piston's reciprocating motion to generate electricity? That obviates camshafts and most other rotating parts, too.

 

Toyota recently showed a prototype engine that does just that. It's called the Free Piston Engine Linear Generator (FPEG). "Free" refers to the fact that the piston isn't attached to a crankshaft; instead, as the piston is forced downward during its power stroke, it passes through windings in the cylinder to generate a burst of three-phase AC electricity. The FPEG operates like a two-stroke engine but adds direct gasoline injection and electrically operated valves. It can also be run like a diesel, using compression rather than a spark plug to ignite its fuel mixture.

 

Toyota says this mechanically simple engine achieves a claimed thermal-efficiency rating of 42 percent in continuous use. Only the best, most complicated, and most expensive of today's gas engines can come close to that number, and only in specific circumstances. Even better, a two-cylinder FPEG is inherently balanced and would measure roughly 8 inches around and 2 feet long. An engine of that size and type could generate 15 hp, enough to move a compact electric vehicle at highway speed after its main drive battery has been depleted.

 

 

 

[SDQDI]

Certainly sounds like a good idea, after all the less moving parts the better and more reliable (theoretically) it should be.

 

I may be stupid but I have to ask, How does the piston move up to compress?

 

 

[PA.]

At the five second mark it points to a Gas Spring Chamber. Not sure why they don't build it as a horizontally opposed twin cylinder.

 

 

[Marty_d]

At the five second mark it points to a Gas Spring Chamber. Not sure why they don't build it as a horizontally opposed twin cylinder.

Or just a double-ended piston with a cylinder head at each end.

 

 

[spacesailor]

Or a horizontally opposed twin cylinder, with a cylinder head at each end, That's four heads. That should be 30 hp, Big enough to power my HUMMELBIRD, LoL

 

But seriously, wouldn't it be much heavier than having That crank in, than having the electrical winding's, plus an electric motor .

 

spacesailor

 

 

[fly_tornado]

what's the lifespan of that spring? Opposing pistons makes much more sense, I suppose you could use compressed air to start it as well

 

 

[pylon500]

Single piston with a head at each end seems the way to go.

 

What I don't understand is why the animation only shows generating a current in one direction?

 

Shouldn't it be generating an AC current with a changing polarity in each direction?

 

 

[facthunter]

IF you had a large force both ways it could. Nev

 

 

[Deskpilot]

I'm confused guys (easily done) Are you discussing the generator motor shown in the video or another. If another, where's the link?

 

 

[facthunter]

I'm agreeing with your firing each end concept diesel jackhammers are the same principle. You can convert the hydrogen (only) direct to electricity with no moving parts, in other concept designs. Nev