2 stroke turbo

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J.A.W.
109
Joined: 01 Sep 2014, 05:10
Location: Altair IV.

Re: 2 stroke turbo

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Why lose the no moving parts 'free' power-charging of the tuned 2T pipe?

I'd reckon Pat Symonds was more likely considering an SI variation on this CI 2T theme:

https://ntrs.nasa.gov/archive/nasa/casi ... 001160.pdf
"Well, we knocked the bastard off!"

Ed Hilary on being 1st to top Mt Everest,
(& 1st to do a surface traverse across Antarctica,
in good Kiwi style - riding a Massey Ferguson farm
tractor - with a few extemporised mod's to hack the task).

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coaster
16
Joined: 30 Jun 2012, 05:10

Re: 2 stroke turbo

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Turbo compounding of 2 stroke diesel works well as the exhaust valves are still actuated by a cam.
We really need to define which 2 stroke to focus on,
1/ the diesel type with sealed crankcase, intake ports at bottom stroke and exhaust cams.
2/ Traditional overlapped ports, expansion exhaust and a 'breathing' crankcase.
Both are very different concepts.

J.A.W.
109
Joined: 01 Sep 2014, 05:10
Location: Altair IV.

Re: 2 stroke turbo

Post

coaster wrote:
31 Jul 2021, 10:09
Turbo compounding of 2 stroke diesel works well as the exhaust valves are still actuated by a cam.
We really need to define which 2 stroke to focus on,
1/ the diesel type with sealed crankcase, intake ports at bottom stroke and exhaust cams.
2/ Traditional overlapped ports, expansion exhaust and a 'breathing' crankcase.
Both are very different concepts.
No, they are not, 2T=2-stroke, which means that every time the piston nears TDC, it fires.

Everything else is 'mere detail' of design, & as that NASA paper duly noted, while poppet
valves could suffice for the relatively low rpm of CI usage (albeit using all 4V for exhaust,
& even though firing rate ~ equals current 4T F1), the higher flow potential of sleeve valves
still remains as a potent upgrade, should it be required, (like for SI usage per R/R-Ricardo).

The paper also notes that the real big, highly efficient Napier 2T diesels did not use poppet
valves, not their massive 'Deltic', nor their turbo-compound 'Nomad' aero-engine...
"Well, we knocked the bastard off!"

Ed Hilary on being 1st to top Mt Everest,
(& 1st to do a surface traverse across Antarctica,
in good Kiwi style - riding a Massey Ferguson farm
tractor - with a few extemporised mod's to hack the task).