[packrat]

I hope you will let me explain what I was meaning when I made my statements. It's not the hydrogen burning but the double ended cylinders.

Two cylinders of the same size is not a way that works. Look at any two stage compressor. The first stage is larger diameter, it takes atmosphere and compresses it to the first point, say 10:1. Now if you transfer that to a second cylinder that is the same size the air will expand in that cylinder to fill the space, then again compress to 10:1. The first compression only heated the air by compression. If that first cylinder compresses its air into a cylinder that is smaller and just big enough to accept it, it will then be compressed further.

Secondly why even use a spark when you are in the realm of diesel/compression ignition?

And I meant no disrespect to you in my first post. From the way it sounded to me this was going to be your first machining job, and didn't want it to be a bad experience for you.

[lkcl]

I hope you will let me explain what I was meaning when I made my statements. It's not the hydrogen burning but the double ended cylinders.

ah ok sorry that's down to the unclear (unannotated) diagram. each cylinder is not double-ended: the underside chamber is used as a mixing chamber, just like in any ported 2-stroke engine. i realise i haven't quite got the scale right: the underside chamber is larger (much lower compression ratio) than the firing chamber. i marked the intake and outtake with arrows, but didn't actually put any words - sorry!

anyway whilst i can't find the picture (animated gif iirc) i've seen online of ported scavenging i at least found this - Two-stroke engine - Wikipedia (loop-scavenging)

from the description in his book, i can see that it's the closest to what bourke used in his design. he didn't do crossflow scavenging, that's for sure. there's a clear description of how the air-fuel mixture goes into a vortex due to the shaping on the top of the cylinder that's presented right at the point where the intake port into the firing chamber is.

Secondly why even use a spark when you are in the realm of diesel/compression ignition?

apparently bourke's design could move into dieselling once it was warmed up. he was however the only person in the world who got his designs to do that, and he unfortunately didn't outline clearly enough how it happened. it was part of the commercial secrets that he kept back, even when later in life his wife's health failed and he began to realise that he wasn't going to realise his dream, and released as much documentation on the engine as he could, instead.

bottom line: i'll have to experiment, and/or would greatly appreciate some advice here.

And I meant no disrespect to you in my first post. From the way it sounded to me this was going to be your first machining job, and didn't want it to be a bad experience for you.

he he - no problem. thank you packrat. your concern is appreciated.