Honda Power Unit Hardware & Software

[saviour stivala]

Lower compression ratio is more stable for engines. Less prone to knock.

I think he is alluding to the shape of the piston surface when he says that.

The manufacturers relied on a pre-chamber ignition however it is suspected thar the crown of the piston helps to shroud the pre-chamber when fuel is injected. It's easier with a higher piston crown. That is my theory.

''The manufacturers relied on a pre-chamber ignition, however it is suspected that the crown of the piston helps shroud the pre-chamber when fuel is injected. it's easier with a higher piston crown, That is my theory''. I am totally taken by surprise with this statement, more so coming from 'PZ'. The rules mandate only one injector per cylinder and the fuel injected must be 'direct injection', Apart from the 'only one injector per cylinder is allowed', direct injection means injector must inject fuel inside cylinder/combustion chamber. Now, making use of ignition by a pre-chamber, mean that ignition is initiated inside the pre-chamber with flames spreading out into combustion chamber, for ignition to be initiated inside the pre-chamber, some of the injected fuel inside the cylinder/combustion chamber, must get inside the pre-chamber. A high piston crown shrouding the pre-chamber, will certainly not help the injected fuel get into the pre-chamber. In my opinion an 'omega' type of piston crown is the type to use in a pre-chamber system formula 1 ICE.

[saviour stivala]

It was a well known fact, across the paddock, the Honda had a distinct advantage in it's deployment and regen abilities. It had been mentioned several times by Merc personnel as well. While their battery had a significant lifespan advantage over the season.

I prefer to go by what I can actually see in the telemetry, and there Merc clearly had more deployment on energy limited tracks. Whether that was down to the battery, or the MGU-H, or something else, I don’t know.

I appreciate that and that's all well and good. It just goes against what a majority are seeing.

Having 'less clipping'/ more deployment on energy limited tracks can only be down to the MGU-H capability of supplying MGU-K directly.

[GhostF1]

Lower compression ratio is more stable for engines. Less prone to knock.

I think he is alluding to the shape of the piston surface when he says that.

The manufacturers relied on a pre-chamber ignition however it is suspected thar the crown of the piston helps to shroud the pre-chamber when fuel is injected. It's easier with a higher piston crown. That is my theory.

Yeah absolutely fair, and a good interpretation of what he's saying. To me, it sort of centres around the idea that their entire "Rapid combustion" technique they developed was based on pressure shockwaves, from the prechamber jets lighting off, causing auto-ignition at the pistons circumference. If the absolute pressure within the chamber during the compression stroke, regardless of piston shape, is not within threshold before ignition, the chances of those shockwaves, upon ignition, having the ability to auto-ignite the mixture at the cylinder extremities will be significantly decreased and as such, won't be a reliable combustion method. I suppose prechamber jet orifice size/shape development could help in some aspects? Not sure.

We don't have all the parameters to go into exactly the type of pressures they are seeing, but rudimentary calcs with what we do know would suggest, if everything remained as it were with a 2025 spec engine, reducing the compression ratio from 18:1 to 16:1 would show a roughly 14% reduction in chamber pressures (before ignition). This is pretty significant, and then there's the new fuels. Some rumours suggesting they're lower octane, so other parameters might be reduced to get the best out of them which could further reduce the likelihood of an ideal environment for rapid combustion.

All hearsay of course!

[Bill]

Most team are having problems with the news fuels apparently because the got components in them that combust at different temperatures so i doubt that having a pu with high compression ratio is a good idea .it could easily lead to engine knocking.

That conflicts with the comments we've heard from the people who ought to know.

Ben Hodgkinson

From a purely technical point of view the compression ratio limit is too low. We have the technology to make the combustion fast enough, so the compression ratio is way too low. We could make 18:1 work with the speed of combustion that we've managed to get, which means there's performance in every tenth of a ratio that you can get. Every manufacturer should really be aiming at 15.999 as far as they dare when it's measured.

Ben is probably thumping his chest ,he is the guy who came with that info that they are having problems with fuels i think after hearing about merc alleged trick of course he will say they are capable of those tricks too .the truth of matter as it has already being discussed some teams have asked fia to use petrol during testing instead of new fuels because they are having problems