A Simple Solution to a Worldwide Crisis

[niky]

I've heard of these, a long time ago.

Apparently does help cool down the combustion chamber somewhat, and on older engine designs, can increase power a little, if done right. Seems to work best on old two-stroke engines.

For modern designs with "swirl" already built into the air flow from the intake valve, probably not so much... and there's a possibility that you're trading operating temperature for increased thermal stress on exposed sharp peaks on the groove edges, which may cause hot-spotting and eventual eating away of the surface.

It'd be interesting to see how a grooved two-valve combustion chamber compares to a more modern four-valve chamber. If the grooves work as well as promised, it could mean cost-savings in manufacturing engines... use less valves, less moving parts, and use the grooves to increase efficiency.

What I haven't seen, though, is data on how grooving affects NOx emissions... that'll be the interesting part... and lower EGTs may interfere with catalytic light up, a big issue, considering cats are required in western countries.