Honda Power Unit Hardware & Software

[gruntguru]

I think there is a special mechanism at play to get that rich mix in the prechamber and to have the proper jet action. I have a few ideas.... Might just mention one now.

idea #1... More than one injector is used (loop hole)
You all already know my first idea already. That two injectors are used. One in the chamber and one outside it.

Idea #2 - boosted EGR used for ignition

My other idea is that a hig pressure EGR pump is used. This pump distributes hot high pressure gasses from the exhaust into the pre-chambers of the different cylinders. The pump raises the pressure to above compression prrssure and solenoid rleases the hot gasses into the prechamber. A plasma may or may not be made from these gases on their way to the chamber.
The jets are made and ignition occurs in the main chamber.

It could be as simple as:
The direct injection nozzle sprays roughly in the direction of the pre-chamber. Any fuel sprayed during the intake stroke will be mixed through the main chamber by the tumble action. When the compression stroke begins, some of this air-fuel mix flows into the pre-chamber. (The quantity of mixture in the pre-chamber increases by about a factor of ten during the compression stroke). If the injector is operated again at a time where this inflow to the pre-chamber is high, the pre-chamber mix will benefit from this extra fuel since the main-chamber at this point is stratified - with rich mixture in the vicinity of the pre-chamber.

From there it is easy to see the pre-chamber will contain a richer mixture than the main chamber. The richness of the pre-chamber can be controlled by biasing fuel delivery toward either the early injection event (leaner pre-chamber) or late injection event (richer pre-chamber).

[gruntguru]

If the injector is not in the pre-chamber, then how would the mixture get richer inside of it?

It is not a different mixture, it is not a rich and a poor one, the spark of the spark plug is used in a smaller space, the same spark that was used to burn the whole mixture of the cylinder is now used to burn only between 3% And 7% of the total of the mixture (pre-combustion chamber), in turn that percentage already ignited is used to combust the rest of the mixture. The concept is that it burns better and more efficiently (needs less richness the mixture) than if the entire mixture of the cylinder is ignited with the spark of the spark plug directly.

There are several papers on TJI include at least one where the pre-chamber has the same AFR as the main chamber. The system will only burn very lean mixtures when the pre-chamber is richer than the main.

[gruntguru]

Since the pre-chamber is mostly likely fed by the main-chamber charge without it's own injector, it's important to not only achieve a good "cleaning" of the pre-chamber during the exhaust stroke, but also controlling the fuel concentration of the part of the mixture which goes into it.

There will be negligible flow through the pre-chamber during intake and exhaust strokes. The holes are tiny and flow is almost entirely a result of pressure difference pre-main. No need for "cleaning". Even if the pre-chamber has 100% exhaust residuals at the start of the compression stroke, it will be less than 10% at the end of compression due to the fresh charge "squeezed" in during the compression stroke.

[glenntws]

Since the pre-chamber is mostly likely fed by the main-chamber charge without it's own injector, it's important to not only achieve a good "cleaning" of the pre-chamber during the exhaust stroke, but also controlling the fuel concentration of the part of the mixture which goes into it.

There will be negligible flow through the pre-chamber during intake and exhaust strokes. The holes are tiny and flow is almost entirely a result of pressure difference pre-main. No need for "cleaning". Even if the pre-chamber has 100% exhaust residuals at the start of the compression stroke, it will be less than 10% at the end of compression due to the fresh charge "squeezed" in during the compression stroke.

If the pre-chamber is nozzled like we think, yes. If however it is completely open (comparable to my idea) the story looks different

[godlameroso]

Then perhaps a happy compromise between the two, entry ports and flame ports on the pre-chamber that work with small one way valves. The pre-chamber entry opening allows A/F mixture in during compression, and closes during combustion, exiting instead through jet holes.

[gruntguru]

Then perhaps a happy compromise between the two, entry ports and flame ports on the pre-chamber that work with small one way valves. The pre-chamber entry opening allows A/F mixture in during compression, and closes during combustion, exiting instead through jet holes.

I think the system (TJI) works fine as-is with optimised jet hole diameter.

[hurril]

You really can not explain it better than Goldameroso has done.

I am asking what puts the food in the mouth ffs. No more stupid analogies.

When someone tries to explain something you do not understand the least should be polite. You asked 3 times the same, do not talk about stupid analogies to a gentleman who with good heart and with the best intentions tried to explain what he does not understand. Need to insult? If you disagree with an argument do you need to insult or put negatives? Some here act like the Holy Inquisition, would beg a little more respect and companionship.

Changing the subject, the problem of vibrations, can not solve them in a provisional way copying existing systems? A glass cup explodes with a frequency X, if you apply a slight pressure in the cup, the frequency of rupture changes, in certain type of oil platforms applies this principle to protect them, could not apply pressure to the vibrating parts to reduce them the maximum possible?

No what actually happened is that I was offered condescending explanations with stupid analogies that do no not, in fact, explain why this works. As can be seen by the fact that some people in here are of the opinion that the injector are inside the pre-chamber whereas others think that it is not. Both positions suffer from a lack of a good explanation as to how the fuel "crosses this barrier."

Outside of F1, this is solved by having two injectors. So no, I am not rude and I'm also not retarded so don't try to explain things with analogies that very clearly misses the actual difficulties.

If the mixture is homogenous in the chamber, for instance, then surely it will still be that having crossed the barrier to enter the pre-chamber. So it'll not be richer, _if_ that is the case. Since it still works then that implies that either the charge is in fact not homogenous or the pre-chamber offers other properties than a richer mixture that makes ignition possible. This is what I asked about.

[hurril]

It could be as simple as:
The direct injection nozzle sprays roughly in the direction of the pre-chamber. Any fuel sprayed during the intake stroke will be mixed through the main chamber by the tumble action. When the compression stroke begins, some of this air-fuel mix flows into the pre-chamber. (The quantity of mixture in the pre-chamber increases by about a factor of ten during the compression stroke). If the injector is operated again at a time where this inflow to the pre-chamber is high, the pre-chamber mix will benefit from this extra fuel since the main-chamber at this point is stratified - with rich mixture in the vicinity of the pre-chamber.

From there it is easy to see the pre-chamber will contain a richer mixture than the main chamber. The richness of the pre-chamber can be controlled by biasing fuel delivery toward either the early injection event (leaner pre-chamber) or late injection event (richer pre-chamber).

I like this explanation.

[Wil992]

Apologies for a possibly simplistic question.
Regs say only 1 injector, but multiple injections are allowed, is that correct?
If that's the case, then would it not make sense to have the injector in the pre chamber, inject once during intake stroke, to give a relatively lean mixture in main and pre, then a second injection immediately prior to ignition, to give a richer mix in the pre chamber than the main?
Am I missing something? Is there any evidence to tell us where the injector is, or is it all just speculation?
Thanks.

[holeindalip]

https://youtu.be/iybnXP6faVU

Could something similar be used as an injector, on a Much smaller scale of course.

[dren]

Apologies for a possibly simplistic question.
Regs say only 1 injector, but multiple injections are allowed, is that correct?
If that's the case, then would it not make sense to have the injector in the pre chamber, inject once during intake stroke, to give a relatively lean mixture in main and pre, then a second injection immediately prior to ignition, to give a richer mix in the pre chamber than the main?
Am I missing something? Is there any evidence to tell us where the injector is, or is it all just speculation?
Thanks.

This is what I am guessing is taking place. It makes sense.

[dren]

I think something similar like this was posted before. What if the pre-chamber is made into the piston? The injector could then have two or more injections during a cycle, one for the lean full cylinder AFR, and one right before ignition for the rich chamber.

[hurril]

https://s4.postimg.org/u9cxny7v1/Untitled.png

Why would it expand through tiny holes to the sides when it can just leak over it through a much larger total area?

[dren]

https://s4.postimg.org/u9cxny7v1/Untitled.png

Why would it expand through tiny holes to the sides when it can just leak over it through a much larger total area?

It's a rough sketch. The gaps would be very small if any. You probably want the small hole jets rather than a larger 'leak over'. Or perhaps not? Just an idea.

[FW17]

https://s4.postimg.org/u9cxny7v1/Untitled.png

Why would it expand through tiny holes to the sides when it can just leak over it through a much larger total area?

It's a rough sketch. The gaps would be very small if any. You probably want the small hole jets rather than a larger 'leak over'. Or perhaps not? Just an idea.

It does not work like that. That gap is constantly changing as the piston moves either up or down.

The jets of plasma out of the pre chamber fires out much before the TDC is reached so that combustion chamber reaches maximum pressure at tdc


The design of the prechamber can be such that a pneumatic actuator or piezoelectric actuator moves the orifice plate as required. Or even the entire prechamber can move down during the intake stroke and fuel in injected through the sides of the prechamber