Crazy car motor idea

[raymo]

I don't see any practical[and financially viable] machine resulting from this,
but if it keeps this old gas emitter's grey matter working, that's fine by me.
[The gas emitter is me, not Alex.] High temp and pressure water was just me musing; I'm well aware that it would be totally impractical[and dangerous.]
Actually, it just occurred to me that as we are talking about small amounts of water, you could heat it with a coil around the exhaust pipe from where it
starts at the exit from the manifold. Nobody seems to have utilised the waste heat, other than to drive turbos. You could pipe it around the interior of the car for heating, like they used to do on trains. Oops, I'm hijacking.
raymo

[sharkbite]

Assuming you can get the water to turn to steam (most steam engine run between 400-500 degrees, and an internal combustion engine is designed to be kept much cooler than this)....

and assuming since you are talking a 6-pot its probably a 4 -stroke?


I'm guessing it would work something like this:

forget spraying water with injectors - there ain't enough heat in the
cylinder without some internal combustion to turn it to steam

Air inlet valves would need to be open for the entire power stroke, to admit
high pressure steam, potentially generated from wrapping the pipes
around the exhaust as previously suggested.
they'd have to be closed for the entire exhaust or "up" stroke.

Outlet valves would need to be closed for the entire down stroke (or "power" stroke) and open for the entire up stroke to exhaust the steam properly.

You would need find a way to delete the compression stroke entirely (all valves closed on an up stroke)

You'd need a separate manifold for the 3 "steam" cylinders so that the spent steam does not cool the exhaust from the proper engine.

Steam engine pistons are "pushed" by steam from first one end, and then the other
to maximise the time that they are providing force to the crank.

you wouldn't be able to do this in a 4-stroke, as the bottom end has no means to control the steam.

[Wavytone]

Alex, your idea isn't new, and indeed there is a somewhat more sophisticated version.

Large diesels do benefit from water, and it's injected into the cylinder in a precise ratio using injectors. The ratio varies depending on the fuel used, rpm and engine load so it's not a trivial exercise, best done by a computer chip. The downside is too much water can destroy the engine fairly quickly.

When the engine is hot, diesels rely on the cylinder being hot enough to detonate the fuel - not a spark plug - so they're pretty hot internally - enough to superheat the steam fast enough to be useful.

When the engine is starting cold however the cylinders are too cool and water won't vaporise so the water injection has to be disabled until the engine is up to full temperature.

This is utilised on big diesels that will run a long time - locomotives, marine diesels, not the tiddlers in cars on short trips to the shops.

Petrol engines rely on a spark for ignition and run cooler - and the slightest trace of water in the fuel will quench the spark even on the next cycle, as anyone knows who has had water in their fuel, so not really feasible.