On 15/11/2016 11:51, NY wrote:
I prefer the Rotary:
https://www.youtube.com/watch?v=0jHRuEkvO8E
Rotaries have always baffled me: how do you get your supply of fuel to
the cylinders without leakage where the stationary fuel tank feed meets
the rotating cylinder block. It's not like an electric motor where slip
rings or a commutator serve the equivalent purpose with electric
current: in the case of fuel, you need to prevent leakage.
You don't send fuel to the cylinders unless you have direct injection.
So a rotary diesel isn't going to work, but a carburetted petrol engine
as those old rotaries will be fine. The cylinders pull in fuel/air.
Since it's suck rather than blow for that mix, any leaks will result in
more air coming in rather than fuel leaking out, and that's easy enough
to cope with by making the mix a little richer.
Presumably rotaries tend to be noisier because each cylinder has its own
separate exhaust pipe - or if there is a common exhaust pipe it cannot
have such elaborate silencer because of the need to balance and minimise
the rotating mass.
These would be plane engines, where the concept of silencer doesn't
really happen :-)
Can rotaries be made to made with supercharging (ie a compressor to
increase air intake pressure)? I suppose it's possible if the compressor
is made to spin with the cylinder block.
Yes
Turbocharging (using exhaust
pressure rather than crankshaft rotation to drive the inlet compressor)
could be "interesting" :-)
Not a chance :-)
In either case, you've got the problem of not
being able to have a large (and therefore heavy) air reservoir to store
boost pressure for cases where the throttle is opened on a slow engine
and high boost is needed at a time when the engine can't yet generate it.
Turbos and superchargers have been used for years (pre-ww2), and don't
use air reservoirs in the way you describe. Turbo lag is real, but the
get rounds for that aren't air reservoirs, and the lag isn't terribly
long anyway. Superchargers only need to work at the same speed as the
engine (or rather proportional to) if you think about it :-)