Honda Power Unit Hardware & Software

[saviour stivala]

"09/11/2018 14:48:- Also when all 4 use TJI, why keep it secret to each other that they do?". With a glass in hand as is traditional over here, PROSIT AMICO, I couldn't have put it any better.

[henry]

"09/11/2018 14:48:- Also when all 4 use TJI, why keep it secret to each other that they do?". With a glass in hand as is traditional over here, PROSIT AMICO, I couldn't have put it any better.

It’s far from secret and anyway knowledge is definitely not understanding. Detail design has always been secretive and always will be so long as there is an advantage to be had. Look at the aerodynamics, as plain as the nose on your face, and yet large differentials in performance.

[tcooper27]

"09/11/2018 14:48:- Also when all 4 use TJI, why keep it secret to each other that they do?". With a glass in hand as is traditional over here, PROSIT AMICO, I couldn't have put it any better.

What secret? Honda and Ferrari openly admit they’re using it and Renault and Mercedes are always tight lipped about anything in their engines.

[Zynerji]

At the beginning of the compression stroke the density in the cylinder (including the pre-chamber) is about 3 times atmospheric. At the end of the compression stroke the density in the combustion chamber (including the pre-chamber) is about 15 times that i.e. 45 times atmospheric. (assuming 15:1 CR). This means that 14/15 ths (93%) of the contents of the pre-chamber have flowed into it during the compression stroke and almost all of this 93% is fresh charge. The very worst case scenario where all the exhaust remaining in the pre-chamber at the end of the exhaust stroke stays there throughout the intake stroke, would still only allow 7% residual exhaust in the pre-chamber.

Right and this is a very good explanation. Why or how, though, would the mixture become denser within the shroud/ pre-chamber than it is without it? I take it this has to entail some vert intricate injector spray pattern and timing combined with some very precise fluid dynamics; because for a denser mixture to end up inside, it has to first form outside the pre-chamber.

If the mixture is not denser within the pre-chamber, then what does it buy? Is there more to having a shrouding or containment than its effect on the mixture? Does containment of the primary ignition event improve its triggering effect in a way that makes it ignite a homogenous mixture better?

So maybe they use fluidic diodes? This brief description http://www.fdx.de/en/products/fluidic-diode/ is for a device for gas turbines. So similar environment. Laminar flow in turbulent out, seems to match well with the needs to Turbulent Jet Ignition. Maybe something as simple as a bell mouth in and sharp edge out on the orifices in the spark plug shroud.

In my mind, the orifices of the jet exits should be two circular drillings, about 15 degrees +/- from level, that are drilled at a tangent into the pre chamber cavity.

Thus, the exit orifices would look like a simple steak-knife blade serration (tooth) that would cause a twin, counter rotating vortex to emerge. If there were 6 of these around the nozzle, I would expect the rotations to actually ingest the unburnt mixture due to the pressure differential within each "slice" of the chamber.

So it would burn quickly, not by spreading the flame front, but by dividing the area into 6ths, then have one side of the pie slice at low pressure while the other at high to cause the unburnt mix to always be sucked into the flame.

[gruntguru]

When this has been discussed, it's been suggested that the mixture "compresses into" the pre-chamber. I, myself, struggle a bit with this and also with how it's cleared well enough post ignition. But I certainly want to believe/ understand it.

At the beginning of the compression stroke the density in the cylinder (including the pre-chamber) is about 3 times atmospheric. At the end of the compression stroke the density in the combustion chamber (including the pre-chamber) is about 15 times that i.e. 45 times atmospheric. (assuming 15:1 CR). This means that 14/15 ths (93%) of the contents of the pre-chamber have flowed into it during the compression stroke and almost all of this 93% is fresh charge. The very worst case scenario where all the exhaust remaining in the pre-chamber at the end of the exhaust stroke stays there throughout the intake stroke, would still only allow 7% residual exhaust in the pre-chamber.

Right and this is a very good explanation. Why or how, though, would the mixture become denser within the shroud/ pre-chamber than it is without it? I take it this has to entail some vert intricate injector spray pattern and timing combined with some very precise fluid dynamics; because for a denser mixture to end up inside, it has to first form outside the pre-chamber.

If the mixture is not denser within the pre-chamber, then what does it buy? Is there more to having a shrouding or containment than its effect on the mixture? Does containment of the primary ignition event improve its triggering effect in a way that makes it ignite a homogenous mixture better?

Try this.
The direct injector fires early in the intake stroke. Although it is directed towards the pre-chamber area, there is no flow into the pre-chamber (through the 6 - 8 orifices which point towards the extremities of the main chamber shape at TDC). This fuel gets mixed throughout the main chamber by the tumble and swirl created during the intake stroke and continuing somewhat during the compression stroke. The result is a well mixed (homogeneous) lean mixture and in the absence of further injection pulses some of this lean mix will be forced into the pre-chamber during the compression stroke.

To create a richer mix in the pre-chamber, simply fire the injector again during the compression stroke creating a richer zone near the pre-chamber. Some of this richer mix will enter the pre-chamber creating the desired AFR at the spark plug. A small zone of richer mix will also remain in the main chamber but the majority of the main chamber will remain at the much leaner AFR required.

[PlatinumZealot]

Easier said than done!!

[gruntguru]

Getting it right is mostly down to time spent on the dyno.

[henry]

Getting it right is mostly down to time spent on the dyno.

Do you think it might be a two stage process? Step1 identify “optimum” conditions in the two chambers, with a separate injector for the prechamber. Step2 try to replicate those results using a single injector.

[PlatinumZealot]

Getting it right is mostly down to time spent on the dyno.

We know Honda and Mercedes Injectors are mounted from the exhaust side of the engine. Has anyone confirmed where the Ferrari injectors are mounted? Reasoning is that the Ferrari is the one with confirmed "Mahle TJI adapted for F1 regulations" so it might give a clue if Honda and Merc method of injection is similar to Ferrari. Of course I bevel all of them have some paid license to Mahle, but some slight differences.

I am starting to believe the "double anchor" theory is likely true... (Injector has a second stage nozzle that shoots sideways into the pre-chamber.

[saviour stivala]

Getting it right is mostly down to time spent on the dyno.

We know Honda and Mercedes Injectors are mounted from the exhaust side of the engine. Has anyone confirmed where the Ferrari injectors are mounted? Reasoning is that the Ferrari is the one with confirmed "Mahle TJI adapted for F1 regulations" so it might give a clue if Honda and Merc method of injection is similar to Ferrari. Of course I bevel all of them have some paid license to Mahle, but some slight differences.

I am starting to believe the "double anchor" theory is likely true... (Injector has a second stage nozzle that shoots sideways into the pre-chamber.

according to Mark Hughes (three years ago) all four were using the Mahle TJI pre-chamber system and also according to him FERRARI confirmed it.

[saviour stivala]

In my personal opinion present turbo ICE combustion:- with fuel injected no less than 60 degrees BTDC compression stroke with around 30 degrees spark advance depending on fuel formulation being used, and with precession combustion pressure measurement by build-in measuring sensor and the capability to control each cylinder individually, programed for the peak combustion pressure point to be reached at 14 degrees after TDC is how the present insane combustion process and pressures are managed.

[dren]

Sounds like they are squirting some fuel in the combustion chamber and igniting it.

[PlatinumZealot]

Getting it right is mostly down to time spent on the dyno.

We know Honda and Mercedes Injectors are mounted from the exhaust side of the engine. Has anyone confirmed where the Ferrari injectors are mounted? Reasoning is that the Ferrari is the one with confirmed "Mahle TJI adapted for F1 regulations" so it might give a clue if Honda and Merc method of injection is similar to Ferrari. Of course I bevel all of them have some paid license to Mahle, but some slight differences.

I am starting to believe the "double anchor" theory is likely true... (Injector has a second stage nozzle that shoots sideways into the pre-chamber.

according to Mark Hughes (three years ago) all four were using the Mahle TJI pre-chamber system and also according to him FERRARI confirmed it.

Mark Hughes is one of the most enjoyable to read, but His technical articles are usually waaaay off the mark (no pun intended). Read Mark Hughes for driver, team and race insight, but never for tech details. He got a lot of stuff wrong in this turbo era and he wont admit it.

[PlatinumZealot]

In my personal opinion present turbo ICE combustion:- with fuel injected no less than 60 degrees BTDC compression stroke with around 30 degrees spark advance depending on fuel formulation being used, and with precession combustion pressure measurement by build-in measuring sensor and the capability to control each cylinder individually, programed for the peak combustion pressure point to be reached at 14 degrees after TDC is how the present insane combustion process and pressures are managed.

I have to say you are very wrong here! There is less need to advance spark timing with TJI. The jet ignition speed is so fast you can pretty much take out all that advance. There are many papers on it and the timing range it is used at. I won't say the figures here because my memory is not that good, but advance is way less than the typical engine.. probably in the 10 to 20 deg range, whereas a typical ICE could be over 35 deg.

[saviour stivala]

We know Honda and Mercedes Injectors are mounted from the exhaust side of the engine. Has anyone confirmed where the Ferrari injectors are mounted? Reasoning is that the Ferrari is the one with confirmed "Mahle TJI adapted for F1 regulations" so it might give a clue if Honda and Merc method of injection is similar to Ferrari. Of course I bevel all of them have some paid license to Mahle, but some slight differences.

I am starting to believe the "double anchor" theory is likely true... (Injector has a second stage nozzle that shoots sideways into the pre-chamber.

according to Mark Hughes (three years ago) all four were using the Mahle TJI pre-chamber system and also according to him FERRARI confirmed it.

Mark Hughes is one of the most enjoyable to read, but His technical articles are usually waaaay off the mark (no pun intended). Read Mark Hughes for driver, team and race insight, but never for tech details. He got a lot of stuff wrong in this turbo era and he wont admit it.

"And he wont admit it" Try tell him that and the next thing you are banned from his site. that is how they operate and trive. All he could tell me three yearsago was "FERRARI had admitted using TJI" andthat was it, punto-a-basta.