Offset cylinder explained.

[Tommy Cookers]

How can an exhaust turbine still be developing significant power in electric supercharging mode with waste-gate open and exhaust gasses by-passing the turbine?.

F1 electric supercharge is using stored electricity at optimum times regardless of thermal efficiency in that mode ....
and ....
only in part do the exhaust gases bypass the turbine
only in part do their pulsations bypass the turbine
the pulses free power eg was used directly to increase aircraft speed - or indirectly via the recovery turbine & propeller
in the 'WGO effect'-by-design Wright the turbine recovery was higher than the compressor power
people (including USSR Zvezda 42 and 56 cylinder CI engine builders) built compound engines for a reason

[vorticism]

In the early days the Ferrari wastegate was almost as large as the main exhaust. Which might suggest effectively a total loss of turbine power when in use.

Working from this image (probably a 2014-2016 engine) I measure the WG feeders as dia 130 px each (27k px sq total area) and the main exhaust as 190 px (20k px sq total). The feeders and valve area are probably oversized to minimize losses but not by much. I would assume the WG area (post valve) for this era engine was roughly equal to the main exhaust area. Given the shared exhaust exit, what if any energy could be harvested by the turbine if an equal area path is available without obstruction?

[saviour stivala]

How can an exhaust turbine still be developing significant power in electric supercharging mode with waste-gate open and exhaust gasses by-passing the turbine?.

F1 electric supercharge is using stored electricity at optimum times regardless of thermal efficiency in that mode ....
and ....
only in part do the exhaust gases bypass the turbine
only in part do their pulsations bypass the turbine
the pulses free power eg was used directly to increase aircraft speed - or indirectly via the recovery turbine & propeller
in the 'WGO effect'-by-design Wright the turbine recovery was higher than the compressor power
people (including USSR Zvezda 42 and 56 cylinder CI engine builders) built compound engines for a reason

Turbo-supercharging (as used in F1) uses the PRESSURE of the exhaust gas. While turbo-compounding (Curtiss-Wright 'PRT'- POWER RECOVERY TURBINE) uses the VELOCITY of the exhaust gas. The F1 engine uses an exhaust gas pressure turbine, with the exhaust having two possible ways out, either through turbine or through an exhaust waste-gate. When waste-gate is open, like water does, the presurized exhaust gas choses the way out of least resistance, which is through the waste-gate. The Curtiss-Wright PTR - POWER RECOVERY TURBINE using the velocity of the exhaust gas, have no exhaust gas pressure, as such it uses no waste-gate. resulting in exhaust gas having only one way out, through the turbine.

[Tommy Cookers]

Wright showed turbine recovery didn't need a drop of exhaust mean-pressure across the turbine
it needed the sonic/supersonic exhaust pulses that persist within exhaust flowing at atmospheric mean pressure

www.enginehistory.org/Piston/Wright/Kuh ... CFacts.pdf

[saviour stivala]

Wright showed turbine recovery didn't need a drop of exhaust mean-pressure across the turbine
it needed exhaust pulses within an atmospheric mean exhaust pressure
the pulses have sonic or supersonic velocity

Wright turbine recovery didn't need a drop of exhaust gas pressure because it used exhaust gas velocity and not exhaust gas pressure.

[Greg Locock]

Yep, once upon a time I wanted to use a high speed alternator with a turbo, modulating the load on the alternator so that it would cancel the exhaust pulses. So, electrical guy gets on with designing the alternator, I start ringing the turbine people. "Oh you want an inertia matched turbine" "Um, what?" And then they sent me the paper discussing that effect, you tune the inertia of the turbo so that it preferentially absorbs the pulses. This explained one puzzle at the time which was why silencing turbo engines was so easy, there isn't much firing frequency noise left after the turbo. All that was well known in the 80s.

[saviour stivala]

The Wright power recovery turbine (PTR) are called ''blowdown'' turbine, a relic from the steam age where steam was vented and allowed to ''blowdawn'' to atmospheric pressure without doing work. Using the 'blowdown'' principle was advantagious because it generated assentailly no back pressure to the engine. The Wright ''blowdown'' system was self regulating, requiring no gauges, sensors or waste-gate/s or other controlling elements.
The turbine used in F1 are different, They are called a pressure turbine, as such it needs a waste-gate as a controlling element, it is only when the waste-gate is opened when the exhaust gas is allowed to ''blowdown'' to atmospheric pressure. This system of waste-gating exhaust gas pressure "blowing-down" to atmospheric pressure is factually demostrated in F1 by the power unit ability to produce the maximum possible power output only when the waste-gate is open and the exhaust gasess are bypassing the turbine. (free load mode - no exhaust gas back pressure on the engine).

[Tommy Cookers]

The turbine used in F1 are different, They are called a pressure turbine, as such it needs a waste-gate as a controlling element, it is only when the waste-gate is opened when the exhaust gas is allowed to ''blowdown'' to atmospheric pressure. This system of waste-gating exhaust gas pressure "blowing-down" to atmospheric pressure is factually demostrated in F1 by the power unit ability to produce the maximum possible power output only when the waste-gate is open and the exhaust gasess are bypassing the turbine. (free load mode - no exhaust gas back pressure on the engine).

the exhaust gases are not bypassing the turbine - the wastegate isn't a diverter
they are partially bypassing the turbine

the continuous controlling element is the continuous MGU-H variability of the load the turbine presents to the gas

your 'factually' 'maximum possible' power output uses stored electricity - and without further data is meaningless

regardless ....
why (and how) would F1 throw away a recovery that Wright etc were happy to use ?
how is the F1 turbine 'different' ? - and unable to recover such power ?

[saviour stivala]

The Wright PRT (turbine) was a blowdown turbine that used exhaust gas velocity as such it had no waste-gate. The formula one turbine is a pressure turbine that uses exhaust gas pressure, when waste-gate is open exhaust gases will bypass the turbine.

[Hoffman900]

You guys can read that paper I linked which gets into how Ferrari pretty much handled it in 2017 vs just arguing past each other about 80yo aircraft.

[vorticism]

You guys can read that paper I linked which gets into how Ferrari pretty much handled it in 2017 vs just arguing past each other about 80yo aircraft.

Does it quantify the changes in turbine work during wastegate operation?

[saviour stivala]

The 80 years old turbo compounded aircraft engine is T. Cooker's pet, the problem is it used a gas velocity operated turbine in contrast to the gas pressure operated turbine used in formula one.
"For the considered high performance power unit the waste-gate is used to increase the engine power by diminishing exhaust manifold pressure. The turbine power extraction is reduced and therefore the MGU-H power recuperation goes roughly to zero''.
Maybe if the above quote from this technical paper is read and understood, the comparison of the 80 year old turbine system with that used by the present formula one will not be pushed out any more, also maybe the claim that that the formula one MGU-H does recuperate with waste-gate open will also stop being pushed out on here.

[Hoffman900]

You guys can read that paper I linked which gets into how Ferrari pretty much handled it in 2017 vs just arguing past each other about 80yo aircraft.

Does it quantify the changes in turbine work during wastegate operation?

Yes. It shows exhaust pipe temperature, pressure, and mass flow of the turbine, modeled and measured (as supplied by Ferrari).

It’s all there and free to download.

[saviour stivala]

In May of 2013 before the new F1 engine formula (1.6l turbo hybrid) hit the track FERRARI (Domenicali) when delivering the annual Morrice Lubbock memorial announced the evolving research partnership with the University of Oxford that resulted in ''The optimal control of formula one car energy recovery system". The first ever known such research.

[Brian.G]

A short discussion and some graphs in the link below in respect to offset in a single cylinder clean sheet design,

https://www.cosentinoengineering.com/fi ... -geometry/

Brian,