3 ms·

This part is dead simple and quite clever. It's on the animated diagram in dark blue, and you can also see one port on the cutaway engine block photo (I've bee

by rleigh 6y ago

This part is dead simple and quite clever. It's on the animated diagram in dark blue, and you can also see one port on the cutaway engine block photo (I've been to see this in real life; the engineering is phenomenal). On the blue diagram I think it's air+fuel at one end and exhaust at the other. When the pistons reach their maximum opposing distance, the injection and exhaust ports are briefly exposed, allowing for entry of fuel/air and exit of exhaust in a single linear movement from one end of the cylinder to the other. Maybe the air is injected before the fuel or at a higher pressure. And if you time the speed of the exchange just right in time for the exhaust ports to be closed over before the compression stroke, you get complete exchange with no fuel wastage. Absolutely nothing like a 4-stroke engine, and not much like common 2-stroke designs either.

jacquesm 6y ago
Clever, and no valves to adjust. I really like this design, and I'm wondering why it never caught on more, it looks as though it would have worked well in a boxer like engine as well, instead of two camshafts and one crank you'd end up with no camshafts and two cranks.
- Judgmentality 6y ago
  > While the Deltic engine was successful in marine and rail use and very powerful for its size and weight, it was a highly strung unit, requiring careful maintenance. This led to a policy of unit replacement rather than repair in situ. Deltic engines were easily removed after breakdown, generally being sent back to the manufacturer for repair, although after initial contracts expired both the Royal Navy and British Railways set up their own workshops for overhauls. I guess nobody wanted to maintain them.
- cstross 6y ago
  What you describe is the Junkers Jumo 204, and the Deltic design was allegedly directly inspired by it. https://en.wikipedia.org/wiki/Junkers_Jumo_204 https://en.wikipedia.org/wiki/Junkers_Jumo_204
  - jacquesm 6y ago
    Wow, what a beast. The displacement to weight ratio is incredible, unfortunately it doesn't seem to produce a whole lot of power for all that weight, though since it is a diesel the torque is probably quite impressive (even though it is for aircraft, where engines typically are fairly low torque). Add a supercharger or a turbo assuming the pistons can stand it and this could very well still be a competitive engine. What a nice design. Thank you once again.
    - Judgmentality 6y ago
      Not to take away from how neat that design is, but my favorite thing about that link is learning that it was manufactured by a now defunct company called Junkers. https://en.wikipedia.org/wiki/Junkers https://en.wikipedia.org/wiki/Junkers
      - jacquesm 6y ago
        The English language association is a pretty negative one but in German it's just another name. Coincidentally, the house I am in right now is heated by a Junkers 'Eurostar' central heating unit. And in Polish 'Junkers' is pretty much synonymous with water heater.

by rleigh 6y ago

jacquesm 6y ago

Clever, and no valves to adjust. I really like this design, and I'm wondering why it never caught on more, it looks as though it would have worked well in a boxer like engine as well, instead of two camshafts and one crank you'd end up with no camshafts and two cranks.

Judgmentality 6y ago
> While the Deltic engine was successful in marine and rail use and very powerful for its size and weight, it was a highly strung unit, requiring careful maintenance. This led to a policy of unit replacement rather than repair in situ. Deltic engines were easily removed after breakdown, generally being sent back to the manufacturer for repair, although after initial contracts expired both the Royal Navy and British Railways set up their own workshops for overhauls. I guess nobody wanted to maintain them.
cstross 6y ago
What you describe is the Junkers Jumo 204, and the Deltic design was allegedly directly inspired by it. https://en.wikipedia.org/wiki/Junkers_Jumo_204 https://en.wikipedia.org/wiki/Junkers_Jumo_204
- jacquesm 6y ago
  Wow, what a beast. The displacement to weight ratio is incredible, unfortunately it doesn't seem to produce a whole lot of power for all that weight, though since it is a diesel the torque is probably quite impressive (even though it is for aircraft, where engines typically are fairly low torque). Add a supercharger or a turbo assuming the pistons can stand it and this could very well still be a competitive engine. What a nice design. Thank you once again.
  - Judgmentality 6y ago
    Not to take away from how neat that design is, but my favorite thing about that link is learning that it was manufactured by a now defunct company called Junkers. https://en.wikipedia.org/wiki/Junkers https://en.wikipedia.org/wiki/Junkers
    - jacquesm 6y ago
      The English language association is a pretty negative one but in German it's just another name. Coincidentally, the house I am in right now is heated by a Junkers 'Eurostar' central heating unit. And in Polish 'Junkers' is pretty much synonymous with water heater.