Lasers instead of spark plugs

keethrax wrote:

16vCorey wrote: Now if they'd just actuate valves with electronic actuators instead of camshafts we'd have infinitely variable valve timing and no parasitic drag of (sometimes multiple) camshafts. It seems like it would be easy enough to keep them in time with a crank sensor. Just have a fail safe that would immediately close the valves if there was a problem and you wouldn't have to worry about interference engine issues.

I have a sneaking suspicion (but no solid evidence or specific knowledge) that electronic actuators with a sufficient mtbf under the conditions they'd be operating at would be too pricey to be worth it. But I'd love to be wrong on that, because if I am, there's all kinds of cool E36 M3 you could do.

I looked into it at one point. here are the issues:

Opening speed is dependent upon temperature and can't be done in stages (example, it you had an infinitely fast, infinitely positionable actuator, you could draw the absolute best cam profile for the valve seat - super quick opening and tapering closing) and the actuators wear out giving slower reactions. Current high grade solenoids are rated for X cycles which turned out to be something like a few hours/days of run time.

They are absolute power hogs

They heat up like mad, adding to the other issues

They are actually not that strong unless you go big.

tuna55 wrote: In reply to 16vCorey: Add in a better valve design than a poppet - a ball for instance would work way better and not oscillate, but spin.

Like these? Coates rotary valve

ReverendDexter wrote:

tuna55 wrote: In reply to 16vCorey: Add in a better valve design than a poppet - a ball for instance would work way better and not oscillate, but spin.

Like these? Coates rotary valve

For some reason they never actually went anywhere, but yeah, sorta like that. I've seen those before. As a ME I'd presume the balls and the seats would need to be made out of ceramic and I have no idea how you'd keep them lubed and keep them sealed, though. I think rotating discs could work with springs pushing down, but it's the same thing, you're going to have to deal with rotaryesque oil consumption.

tuna55 wrote: I looked into it at one point. here are the issues: Opening speed is dependent upon temperature and can't be done in stages (example, it you had an infinitely fast, infinitely positionable actuator, you could draw the absolute best cam profile for the valve seat - super quick opening and tapering closing) and the actuators wear out giving slower reactions. Current high grade solenoids are rated for X cycles which turned out to be something like a few hours/days of run time. They are absolute power hogs They heat up like mad, adding to the other issues They are actually not that strong unless you go big.

Thanks! I suspected many of these were the case, but it's a bit out of any area I have real knowledge of.

How does one keep the lenses from fouling?

Jay_W wrote: How does one keep the lenses from fouling?

I dunno, that's the one thing I've been trying to puzzle out.