Revetec crankless engine

[F.M]

An interesting twist on conventional engine design....looks like it works a treat too..

http://autospeed.drive.com.au/cms/A_1

www.revetec.com

[stevieturbo]

Seen that some 2-3 years ago, they were looking sponsors, they had a few videoclips of a subaru based engine running on a dyno...

Wonder has it progressed any ?

Edited by stevieturbo on Monday 15th January 01:08

[MTv Dave]

Looks likea good idea - I used to wonder why we use con rods when they don't really do the job we want in the right places. I just assumed that stuff like this was tried and thrown out in the past for whatever reason (not that I would have come up with anything like this).

The figures don't seem that impressive in their latest video, but I have no idea what displacement they have in their test engine I suppose so maybe I shouldn't start throwing stones

I'm also not convinced that there would be no rotational inertia passed through to the mounting datums - sure you can balance the masses, but they are still in different places so you can't get it perfect - though it may be better than using con rods and cranks like we do today.

I'd like to see a high-performace one in a light, low kit car and see what it can do!

[ATG]

A really interesting idea. Being able to engineer how long the piston stays near TDC and BDC during the cycle and modifying the leverage angle against the crankshaft would seem to offer big potential benefits. It really is great piece of lateral thinking. But can you actually build one that works? Can you actually keep the rollers in contact with cam lobes so that the two don't hammer against each other and cause lots of wear? I'd fear this design would give you the conventional problems of cam wear magnified many times due to the forces involved. Perhaps in lower power applications this is less of a problem ... but in low power applications, fuel efficiency is less of a consideration too.

[MTv Dave]

the revtech site has videos of the prototype engine running. It sounds fine; just like a normal motor, but I see what you mean about the wear of the bottom end. The pictures of the parts leads me to believe that they use pretty big bits compared to the top end though, so maybe the wear can be over more surface and so take much longer to show itself. Then again, it can take quite a while for a top end to wear out, but I guess there's a lot less energy and power involved with it.

I like the idea (though it does scare me a bit) of a hollow crank too - means you can do some clever stuff with variable shaped cams to follow the piston rollers and so vary the engine characteristics on the fly