Honda Power Unit Hardware & Software

[63l8qrrfy6]

5.10.2 There may only be one direct injector per cylinder and no injectors are permitted upstream of the intake valves or downstream of the exhaust valves. Only approved parts may be used and the list of parts approved by the FIA, and the approval procedure, may be found in the Appendix to the Technical Regulations.

Pop quiz hotshot: why is combustion in spark ignition more efficient at higher piston speeds?

From someone with a poor understanding of combustion.

1. High charge kinetic energy imparted by piston velocity.

2. Less time for heat transfer into walls.

3. Maybe more spark advance if the knock limit is indeed shifted?

[63l8qrrfy6]

by Spa/Silvestone Alonso will sign a contract whit another team....i know this is Honda PU thread, just saying.

And to Mr.Flap why would cylinder sealing matter at any point other than during combustion itself? Would it not add to pumping losses?

You are correct, I don t think it matters. Oil is unlikely to degrade due to excessive blow by during 1 race and oil consumption due to improper scraping is probably not a concern. The limiting factor for tension must be related to ring radial collapse.

Honda mentioned that in the N/A era they were concerned about crank case pressure raise due to ring flutter. Also the sealing was so poor they were consuming 1 liter of oil for each 30 km. They used to have 'qualifying rings' which were swapped for higher tension 'race rings' that would be good for 1 liter of oil per 100 km.

[Vortex37]

İsn't there any company good on direct injection pre-chamber ignition? When I googled I can see that Mann uses this tech on its engines. Toyota were partner with Mann when they were in F1. I think these kind of heavy industiry companies good on big powers and reliability. So Honda also can work with Mann, Caterpiller etc. Mahle is just an example and not matter who is its owner.

The combustion tech currently used in F1 is cutting-edge. There are no companies out there (except Mahle) with more knowledge than the F1 engine teams.

Respectfully, plenty of knowledge, and numerous companies have patents or improvement patents on ignitors and/or prechamber geometry for multiple fuel types. eg Federal Mogul, Borg Warner, Caterpillar, GM. These cover prechamber in the piston bowl, prechamber swirl characteristics etc etc. This search link is a start, remove assignee to get others.

[63l8qrrfy6]

I think wazari is hinting at the fact that higher piston speeds raise the knock limit.

It was said that v8 engines did not knock and CR was only limited geometrically.

Less time spent at said compression?

Not sure how it works really. Kevin Hoag from SWRI mentioned this several times and it was later confirmed by an ex F1 engineer.

[dren]

I think wazari is hinting at the fact that higher piston speeds raise the knock limit.

It was said that v8 engines did not knock and CR was only limited geometrically.

Less time spent at said compression?

Not sure how it works really. Kevin Hoag from SWRI mentioned this several times and it was later confirmed by an ex F1 engineer.

I'm going to guess a better mixture with faster moving pistons, plus less fuel and air to mix. Just my guess, though.

[Anony Mous Engineerd]

The more I look at the TJI injection scheme, the more I doubt it is actually implemented like the pictures in the Mahle explanations of it.

https://www.google.com/patents/US20120103302

I think what ever gains you could get from the pre-chamber combustion, would be eliminated by what would seem to me be, really poor atomization and homogeneous distribution in the rest of the main part of the combustion chamber...

What happens to the spray from the injector, impinging on the internal surfaces of that little "pre-chamber" to eventually leaking out the rest of the holes in that extra part? I think the losses from that, would be greater than the pre-chamber. How could the injector spray not just "leak out" of that tiny chamber? How does fuel not build up in the pre-chamber and completely soak the spark plug creating a fouling concern? ? I think a fine atomization from the injector, and a great deal of tumble leading to a high value of overall turbulent kinetic energy right around a normal parkplug would be better in this racing application than the TJI.

All the pressure and velocity of fuel particles, I'd bet, would be gone by the time the fuel leaves the injector and builds up in the pre-chamber. Could the rapidly rising pressure in the combustion chamber cause an even higher likely hood that fuel coming out of the pre-chamber would not be well atomized.....

Until I see real pictures from an F1 engine with that system. I don't think any team has actually implemented it (in the fashion shown in mahle patents and websites.) , and this is a red-hearing...

[63l8qrrfy6]

I also wonder if higher speeds allow them to run the turbo at higher boost and open the intake valve earlier/longer to reduce piston pumping work and lower charge temperatures as in a Miller cycle. Again, this should allow more spark advance.

[PlatinumZealot]

5.10.2 There may only be one direct injector per cylinder and no injectors are permitted upstream of the intake valves or downstream of the exhaust valves. Only approved parts may be used and the list of parts approved by the FIA, and the approval procedure, may be found in the Appendix to the Technical Regulations.

Pop quiz hotshot: why is combustion in spark ignition more efficient at higher piston speeds?

From someone with a poor understanding of combustion.

1. High charge kinetic energy imparted by piston velocity.

2. Less time for heat transfer into walls.

You could end up transferring more heat for a given time since your cylinders would cycle 10% more in a given time.
Remember the fuel flow rate is limited.

[63l8qrrfy6]

5.10.2 There may only be one direct injector per cylinder and no injectors are permitted upstream of the intake valves or downstream of the exhaust valves. Only approved parts may be used and the list of parts approved by the FIA, and the approval procedure, may be found in the Appendix to the Technical Regulations.

Pop quiz hotshot: why is combustion in spark ignition more efficient at higher piston speeds?

From someone with a poor understanding of combustion.

1. High charge kinetic energy imparted by piston velocity.

2. Less time for heat transfer into walls.

You could end up transferring more heat for a given time since your cylinders would cycle 10% more in a given time.
Remember the fuel flow rate is limited.

I am sure you will transfer more heat overall, but per cycle (ie as a function of crank angle) it should be less.

[Vortex37]

I think wazari is hinting at the fact that higher piston speeds raise the knock limit.

It was said that v8 engines did not knock and CR was only limited geometrically.

Less time spent at said compression?

Not sure how it works really. Kevin Hoag from SWRI mentioned this several times and it was later confirmed by an ex F1 engineer.

Speculation - Assuming that they are using tji, though I can't remember seeing any absolute confirmation, was he talking about 'knock' or just combustion instability from prechamber igniter issues. I see those things as two different issues but a similar result. If it was old style knock, and the issue was caused by interfering pressure waves, then higher rpm might give a higher average pressure over time, depending on valve timing.

If it was a pre-chamber problem, then it really depends on the design of the igniter and placement of the fuel injector. I would think that it would be concentric. Lots of things to consider in the pre-chamber, that would be affected by higher rpm, swirl, in/out pressures/over time etc

Prechamber igniter designs.

[etusch]

The more I look at the TJI injection scheme, the more I doubt it is actually implemented like the pictures in the Mahle explanations of it.

https://www.google.com/patents/US20120103302

I think what ever gains you could get from the pre-chamber combustion, would be eliminated by what would seem to me be, really poor atomization and homogeneous distribution in the rest of the main part of the combustion chamber...

What happens to the spray from the injector, impinging on the internal surfaces of that little "pre-chamber" to eventually leaking out the rest of the holes in that extra part? I think the losses from that, would be greater than the pre-chamber. How could the injector spray not just "leak out" of that tiny chamber? How does fuel not build up in the pre-chamber and completely soak the spark plug creating a fouling concern? ? I think a fine atomization from the injector, and a great deal of tumble leading to a high value of overall turbulent kinetic energy right around a normal parkplug would be better in this racing application than the TJI.

All the pressure and velocity of fuel particles, I'd bet, would be gone by the time the fuel leaves the injector and builds up in the pre-chamber. Could the rapidly rising pressure in the combustion chamber cause an even higher likely hood that fuel coming out of the pre-chamber would not be well atomized.....

Until I see real pictures from an F1 engine with that system. I don't think any team has actually implemented it (in the fashion shown in mahle patents and websites.) , and this is a red-hearing...

https://parts.cat.com/en/catcorp/330-1782
https://parts.cat.com/en/catcorp/218-3894
I can't explain my idea because of poor english but it could be done that an injector near to prechamber with one injection hole looks inside prechamber and others to main.

[godlameroso]

by Spa/Silvestone Alonso will sign a contract whit another team....i know this is Honda PU thread, just saying.

And to Mr.Flap why would cylinder sealing matter at any point other than during combustion itself? Would it not add to pumping losses?

You are correct, I don t think it matters. Oil is unlikely to degrade due to excessive blow by during 1 race and oil consumption due to improper scraping is probably not a concern. The limiting factor for tension must be related to ring radial collapse.

Honda mentioned that in the N/A era they were concerned about crank case pressure raise due to ring flutter. Also the sealing was so poor they were consuming 1 liter of oil for each 30 km. They used to have 'qualifying rings' which were swapped for higher tension 'race rings' that would be good for 1 liter of oil per 100 km.

IIRC oil scraping is done partly by the second compression ring, and primarily by the oil control rings which aren't as affected by combustion pressure as the top ring itself(although it is to some extent). The second compression ring shears the oil on the cylinder walls, and is pushed outward by the taper(or sharp corner) on the underside of the ring as it travels downward.

And yes, increased turbulence due to higher piston speed improves mixing as well as the reasons you stated.

[rgava]

There were 3 combustion process designs decided upon and with strong advice from outside consultants this current spec was built.

Lots of posts pointing to outside help as "the solution" for Honda troubles and the truth is outside consultancy strongly advised to go the route which failled miserably.

[Vortex37]

The more I look at the TJI injection scheme, the more I doubt it is actually implemented like the pictures in the Mahle explanations of it.

https://www.google.com/patents/US20120103302

I think what ever gains you could get from the pre-chamber combustion, would be eliminated by what would seem to me be, really poor atomization and homogeneous distribution in the rest of the main part of the combustion chamber...

What happens to the spray from the injector, impinging on the internal surfaces of that little "pre-chamber" to eventually leaking out the rest of the holes in that extra part? I think the losses from that, would be greater than the pre-chamber. How could the injector spray not just "leak out" of that tiny chamber? How does fuel not build up in the pre-chamber and completely soak the spark plug creating a fouling concern? ? I think a fine atomization from the injector, and a great deal of tumble leading to a high value of overall turbulent kinetic energy right around a normal parkplug would be better in this racing application than the TJI.

All the pressure and velocity of fuel particles, I'd bet, would be gone by the time the fuel leaves the injector and builds up in the pre-chamber. Could the rapidly rising pressure in the combustion chamber cause an even higher likely hood that fuel coming out of the pre-chamber would not be well atomized.....

Until I see real pictures from an F1 engine with that system. I don't think any team has actually implemented it (in the fashion shown in mahle patents and websites.) , and this is a red-hearing...

https://parts.cat.com/en/catcorp/330-1782
https://parts.cat.com/en/catcorp/218-3894
I can't explain my idea because of poor english but it could be done that an injector near to prechamber with one injection hole looks inside prechamber and others to main.

Just have the fuel injector concentric with a small hole into the prechamber, and the main flow through the in/out holes?

[dren]

There were 3 combustion process designs decided upon and with strong advice from outside consultants this current spec was built.

Lots of posts pointing to outside help as "the solution" for Honda troubles and the truth is outside consultancy strongly advised to go the route which failled miserably.

Or was poorly implemented. We don't know.