HCCI

All that has to do with the power train, gearbox, clutch, fuels and lubricants, etc. Generally the mechanical side of Formula One.
saviour stivala
saviour stivala
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Re: HCCI

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Whatever ‘type’ of regulations were ever used and regardless the ‘label’ they were given by those following the sports as well as by those taking part in GP racing, the regulated sports was always followed even by those that do not agree by said regulations. In the history of GP racing the sports was never so tightly regulated as at present, yet as regards the highly regulated ‘powertrain’, the present ‘powertrain’ is the most powerful, the most efficient and the most sophisticated ever used. And all that regardless the tight/strict rules/regulations that after all did a good job preventing a financially distractive free-for-all development race.

J.A.W.
J.A.W.
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Re: HCCI

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saviour stivala wrote:
Wed Apr 27, 2022 4:06 am
‘spocom – spontaneous combustion’ is a type of ‘uncontrollable’ combustion that is avoided at all cost by engine designers. Modern formula 1 engine design trends aims to achieve a ‘rapid’ or as fast a combustion as can be short of it being ‘spontaneous’.
Yeah, the same def' applied to highly tuned 2-stroke G.P. bikes, pumping ~15bar BMEP,
they ran ignition timings that fired the mixture very close to TDC, & were running real cool, too..

(& I have a ~30 year old classic Mercedes-Benz coupe, which features a Cosworth-derived
DOHC 4V top-end, even back then it came factory equipped with multiple ignition control inputs,
integrated by an expensive Siemens micro-processer which took signals from knock sensors &
multiple temperature sources as inputs, then adjusted ignition/cam-advance timings accordingly
with different maps available per fuel quality for its then - fairly high 10-1 static compression ratio).
"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).

johnny comelately
johnny comelately
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Re: HCCI

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I think this graph is a good basis for discussing the F1 combustion design:
Because this is a complex and largely unknown subject, I'm want to have some terms of reference to enable the discussion that might discover how they are achieving reliable, powerful combustion in an environ hitherto not achieved - 1.4 lambda

Image

NL_Fer
NL_Fer
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Re: HCCI

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It looks like the mixture at the wall, already ignites, before the jets ever exit the pre-chamber. So they use the pre-chamber as a rapid pressure starter, for the lean mixture to auto-ignite.

johnny comelately
johnny comelately
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Re: HCCI

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NL_Fer wrote:
Sat Apr 30, 2022 8:14 am
It looks like the mixture at the wall, already ignites, before the jets ever exit the pre-chamber. So they use the pre-chamber as a rapid pressure starter, for the lean mixture to auto-ignite.
Yes, but I think the prechamber jets create the main chamber pressure rise first to "autoignite" the end gases.
It is the control for reliable predictability of the autoignition phase that is key

johnny comelately
johnny comelately
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Re: HCCI

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Purely as an aside, a look at combustion with 120:1 compression plus afterburner, all to make a big hole at the back of the shed....and blew the papers off my desk


NL_Fer
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Re: HCCI

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johnny comelately wrote:
Sat Apr 30, 2022 11:12 am
NL_Fer wrote:
Sat Apr 30, 2022 8:14 am
It looks like the mixture at the wall, already ignites, before the jets ever exit the pre-chamber. So they use the pre-chamber as a rapid pressure starter, for the lean mixture to auto-ignite.
Yes, but I think the prechamber jets create the main chamber pressure rise first to "autoignite" the end gases.
It is the control for reliable predictability of the autoignition phase that is key
I don’t see the jets coming. It is just the shockwave from the pre-chamber which travel even faster.

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Zynerji
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Re: HCCI

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NL_Fer wrote:
Sat Apr 30, 2022 3:10 pm
johnny comelately wrote:
Sat Apr 30, 2022 11:12 am
NL_Fer wrote:
Sat Apr 30, 2022 8:14 am
It looks like the mixture at the wall, already ignites, before the jets ever exit the pre-chamber. So they use the pre-chamber as a rapid pressure starter, for the lean mixture to auto-ignite.
Yes, but I think the prechamber jets create the main chamber pressure rise first to "autoignite" the end gases.
It is the control for reliable predictability of the autoignition phase that is key
I don’t see the jets coming. It is just the shockwave from the pre-chamber which travel even faster.
I'd like to see the infrared cam before backing that statement. If it is a vortex loop, it could be in a quasi-plasma state, and we only see the visible light when it breaks down at the cylinder wall.

johnny comelately
johnny comelately
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Re: HCCI

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NL_Fer wrote:
Sat Apr 30, 2022 3:10 pm
johnny comelately wrote:
Sat Apr 30, 2022 11:12 am
NL_Fer wrote:
Sat Apr 30, 2022 8:14 am
It looks like the mixture at the wall, already ignites, before the jets ever exit the pre-chamber. So they use the pre-chamber as a rapid pressure starter, for the lean mixture to auto-ignite.
Yes, but I think the prechamber jets create the main chamber pressure rise first to "autoignite" the end gases.
It is the control for reliable predictability of the autoignition phase that is key
I don’t see the jets coming. It is just the shockwave from the pre-chamber which travel even faster.
The prechamber spark initiation is what gives the predictability and therefore control.
Consistent timing being one of the challenges with HCCI.
IMHO

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PlatinumZealot
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Re: HCCI

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gruntguru wrote:
Tue Apr 26, 2022 10:28 pm
As suggested by @johnny comelately, this probably deserves a thread of its own. Over to you johnny.

Another release by Honda suggest that they use a form of plasma jet that extends to the cylinder walls first. This initial Jet of free radicals doesn't ignite the fuel mixture until it slows down near the walls, or something like that.

My guess is that is must be something in the fuel that creates these long-lived free radicals.
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johnny comelately
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Re: HCCI

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PlatinumZealot wrote:
Sun May 01, 2022 4:13 pm
gruntguru wrote:
Tue Apr 26, 2022 10:28 pm
As suggested by @johnny comelately, this probably deserves a thread of its own. Over to you johnny.

Another release by Honda suggest that they use a form of plasma jet that extends to the cylinder walls first. This initial Jet of free radicals doesn't ignite the fuel mixture until it slows down near the walls, or something like that.

My guess is that is must be something in the fuel that creates these long-lived free radicals.
5.11.1 Ignition is only permitted by means of a single ignition coil and single spark plug per cylinder. No more than five sparks per cylinder per engine cycle are permitted.

The use of plasma, laser or other high frequency ignition techniques is forbidden

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PlatinumZealot
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Re: HCCI

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johnny comelately wrote:
Sun May 01, 2022 10:29 pm
PlatinumZealot wrote:
Sun May 01, 2022 4:13 pm
gruntguru wrote:
Tue Apr 26, 2022 10:28 pm
As suggested by @johnny comelately, this probably deserves a thread of its own. Over to you johnny.

Another release by Honda suggest that they use a form of plasma jet that extends to the cylinder walls first. This initial Jet of free radicals doesn't ignite the fuel mixture until it slows down near the walls, or something like that.

My guess is that is must be something in the fuel that creates these long-lived free radicals.
5.11.1 Ignition is only permitted by means of a single ignition coil and single spark plug per cylinder. No more than five sparks per cylinder per engine cycle are permitted.

The use of plasma, laser or other high frequency ignition techniques is forbidden
It's not conventional plasma ignition. Just as much as the spark plasma on the spark plug is not a conventional plasma ignition. Both have charged gasses but the plasma ignition is steady high voltage streams. Plasma ignition uses specific hardware and voltage to achieve this.

For the Honda engine it is using the spark to shoot a stream of free radicals. So technical it is a charged gas but I think it doesn't use temperature for igntion at first. I think it uses the free radicals to enchance combustion.

Just to show how role of fre radicals in combustion. I think Honda found a way to manipukate this. (the singlet radical they speak of is oxygen)

https://chem.libretexts.org/Bookshelves ... 20material.
Combustion consists of various radical chain reactions that the singlet radical can initiate. The flammability of a given material strongly depends on the concentration of free radicals that must be obtained before initiation and propagation reactions dominate leading to combustion of the material. Once the combustible material has been consumed, termination reactions again dominate and the flame dies out. As indicated, promotion of propagation or termination reactions alters flammability. For example, because lead itself deactivates free radicals in the gasoline-air mixture, tetraethyl lead was once commonly added to gasoline. This prevents the combustion from initiating in an uncontrolled manner or in unburnt residues (engine knocking) or premature ignition (preignition).
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johnny comelately
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Re: HCCI

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That is good information, thank you.
At the molecular level it is interesting and should be informative how the atoms are behaving in response to first pressure and then temperature. Do these produce the ionisation that helps the process?

J.A.W.
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Re: HCCI

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Perhaps the claims for low NOx emissions are related?

There is plenty of electrical potential to create O3 onboard,
& add an H2O2 compound via the fuel, for a fierce but clean catalytic action...
"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).

johnny comelately
johnny comelately
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Joined: Thu Apr 09, 2015 11:55 pm
Location: Australia

Re: HCCI

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J.A.W. wrote:
Mon May 02, 2022 6:53 am
Perhaps the claims for low NOx emissions are related?

There is plenty of electrical potential to create O3 onboard,
& add an H2O2 compound via the fuel, for a fierce but clean catalytic action...
I dont understand chemistry well enough to have an opinion on the ozone production and fuel interaction with that.
But re NOx all I understand is that in any combustion with air (78% N) the NOx can form but the lower the relevant temp it is less??
One point in all this is that the formula is trying to be road and environment relative, despite the irony