Is Port Energy validation just around the corner?????

[juuhanaa]

Hopefully I have entered all of your flow numbers correctly. Before looking into port energy I think you need to look into why your manifold chokes your intake flow numbers so.

Stan

Juhana_Percent_flow_change_with_manifold.gif

Thank you, I appreciate you taking the time to look at the flow sheets. I would like to show tech stuff regarding my example engine, and i hope this gives a valuable information for this topic. Your saying "I have never seen anything where Port Energy was that low." makes me thinking people rarely try explain what theyr thinking, when making 1.5 ft lbs/cid using modified OEM parts right? Im just making observations, and so far this subject looks it is no exception in "there are different ways to skin a cat".

Link below is a homologation form regarding the production car engine im referring to. On first pages we can check some details about the engine including what the manifold restriction looks like. If we dig further, we find things like restriction plate and different versions of kitcar engines.

https://historicdb.fia.com/sites/defaul ... roup_a.pdf

harmonics and volumetric efficiency.jpg

Megane F7R 2.0 harmonics.png

Cylinder head had a mild porting, stock valves with top cut and 3 angle valve job around 45 sealing, stock size port at the manifold flange. The biggest restriction was the exhaust manifold... Calculus used in resonance tuning answer the question when, but what i think is interesting the Port Energy graphs may answer how effective the wave is in filling the cylinder. Please notice the runner volume 535cc + cylinder head volume 113cc ---> Cylinder displacement is 500cc and im estimating the ve 120 % In other hand it seems to answer the questions how effective the cylinder ramming effect is and how the exhaust works, things that are related to cylinder displacement, but not necessarily work for everything.



-juhana

[juuhanaa]

From a strictly theoretical sense, read about variable area nozzles on jet engines. Obviously you can't have that in an internal combustion engine because the chamber does more than assist with pressure recovery of the port.



You could always produce a port this way, maybe with a divergent section and a convergent section, however, the valve is fixed. Additionally, how much power would you have to produce to overcome the weight disadvantage and potential efficiency losses? How much is there to gain considering the use of multiple gear transmissions?

A quick search of patents shows many different ways of attempts to vary the port area. It's not a new idea by any means.

Variable exhaust nozzle VEN uses hydraulic actuators to drive the system. Direct injection engines has already hi fuel pressures, but they dont necessarily have any SSR on a intake port, and they can adjust the length The gear transmission could be something if the port adjusts according to the valve lift, somehow like in my drawing?

Homologation paper, how Peugeot fitted the restriction plate inside every individual runner, in the kitcar era. (I think Renault just widened the floor of SSR)

PEUGEOT 306 S16.jpg

Drawing about "variable geometry port".

Variable geometry intake port.png

-juhana

[hoffman900]

The optimum port shape is going to have to change along the whole length to work with a change in MCSA. It's not as simple as having something like a camera aperture, so it needs to occur along the entire port / intake tract length

[juuhanaa]

The optimum port shape is going to have to change along the whole length to work with a change in MCSA. It's not as simple as having something like a camera aperture, so it needs to occur along the entire port / intake tract length

Im just thinking... The optimum port shape depends, but it is interesting that one bend changes everything, by changing the local velocities along the entire port, including MCSA. The drawing act like a variable venturi. Its not only about the changes in walls, it is how this area inside a port is utilized by the flow, for example: Cylinder head flows more @ some lift point with the manifold, but if we try a different manifold which has a bigger upstream and no bend, maybe it flows same than without a manifold?



-juhana

[digger]

for variable port size i remember on these forums reading about a cone in a cone and moving them axially varied the area