Honda Power Unit Hardware & Software

[roon]

Everything on schedule. Lot's of testing and work...............

Also, Wazari, while you are here...

It seemed like you had some knowledge of the Mercedes "vortex exhaust" rumor. I think what it might be referring to is toroidal vortices, also known as vortex rings. Specifically, they might be inducing vortex rings within the exhaust manifold in order to better entrap heat within each exhaust pulse. Vortex rings are know for their ability to transport heat and gases across long distances, due to their self-contained, self-circulating nature. The specific type of flow I'm referencing is known as poloidal flow, although there are other types.



If a vortex ring can be induced after the exhaust port and made to traverse the length of the manifold before bursting into the turbine inlet, you might minimize heat lost to the manifold's wall. This satisfies the other piece of the rumor—that it was about maximizing heat retention.

[youtube]https://youtube.com/watch?v=Sj9irzI-Pzw[/youtube]

Initially when I heard "vortex," my mind went to a helical vortex. But helical vortices tend to be open-ended and not self circulating. So, to me, it didn't quite satisfy the heat retention quality. I thought about the concept of self-containment a little more and started visualizing different types of vortical flow. Ring vortices seem to fit the bill. I have an illustration of the idea and hope to post it soon.

What do you think? Best of luck with preparations.

[Wazari]

Mr. Roon, I think you are definitely on the right track. Someone mentioned that HPP had a innovative exhaust to be introduced and I had heard through the "rumor mill" that it was some sort of vortex, high heat retention system. I think that all the manufacturers would have at least explored some variation of this process in the exhaust system.

[roon]

Thank you, sir. My initial thought regarding the design involves an enlarged diameter exhaust manifold piping, such that it doesn't constrict or compress the vortex ring formation & travel. I hope to post a drawing tomorrow. Looking forward to seeing pit photos of the new Honda PU later this season.

[godlameroso]

Would there be any benefit to operating the V6 as an I3 or V4 or V-twin? i.e. Dividing the fuel flow allowance through fewer cylinders? More fuel & higher charge per cylinder. Furthermore: dummy pistons and valves to minimize losses to the unused cylinders.

Food for thought; How can we make the crankshaft as short as possible? Could this affect resonance?

Everything on schedule. Lot's of testing and work...............

Join the piston connecting rods together. Shared conrod big-ends, or some other form of linkage to allow opposing cylinders to occupy the same plane. No offset of the cylinders between banks. Voila: shorter crank, shorter block, and you still satisfy the three crank throw rule. Regulations regarding connecting rod design are pretty open aside from material specifications.

Edit: regarding resonance, if opposing cylinders are operating in the same plane, there would be no "twisting" moment, or yaw, about the vertical axis. When the pistons are offset, as is commonly the case when two pistons share the same throw, there would be a twisting force seen by the crank throw as it pushes and pulls on the connecting rods. A co-planar cylinder layout would eliminate this and perhaps improve journal wear & reduce resonant frequencies which might result from a minutely warping crankshaft throw. Which would have further durability benefits for the rest of the assembly. The pistons themselves should also see some reduced side-loading, so perhaps there are some frictional benefits as well.

You mean kind of like how a radial engine is put together? Designing the counter weights on such a crank must be incredibly difficult. That alone could cause resonance issues, but I don't think that's what we're hearing, could be caused by just back pressure and low rpm, especially if the engine works as two I3's. Which would make sense if the two banks are co-planar like roon said.

I guess the biggest challenge would be this:

5.17.3 Connecting rods must be manufactured from iron or titanium based alloys and must be machined from a single piece of material with no welded or joined assemblies (other than a bolted big end cap or an interfered small end bush).

[roon]

There might still be enough room in that wording to add linkages or get clever with the conrod & end cap shapes.

There are knife-and-fork type conrod designs for co-planar sharing of a journal. Perphaps this is what you're refering to. Aside from that, perhaps link one conrod to another, and then link that one to the crank—both would technically still have a big end, just in different locations.

Some other thoughts... The regs specify bank angle but maybe not the intersection of the cylinder centerlines with the crankshaft centerline. Said another way: raise the v while keeping the crankshaft in its regulated position. Might provide some extra space for clever linkages, at a CoG penalty...

Another idea: A 2-4 asymmetrical bank V6 and a two throw crank would give you two symmetrically loaded crank journals (three per), and a short crankshaft length partly defined by the distance between the centers of the 4 cylinder bank's inner & outer bores. I don't see engine symmetry imposed as a rule, unless I'm missing it. And it might explain weird engine sounds, since the V6 would be composed of two V3s.

[Wazari]

I don't mean to steer people in the wrong direction or when I say food for thought, it is exactly what is happening.

Some mentioned the difference in resonance in the new PU vs. the older PU, and yes there is a definite difference by design. I mentioned crankshaft length to maybe have some of you think in a different direction other than cylinder cutting or "dummy" pistons. I can't say too much but keep in mind the restriction in V angle and then maybe think about possible journal design while maintaining restrictions in stroke of ICE. Definitely no "piston slap".

[godlameroso]

Another idea: A 2-4 asymmetrical bank V6 and a two throw crank would give you two symmetrically loaded crank journals (three per), and a short crankshaft length partly defined by the distance between the centers of the 4 cylinder bank's inner & outer bores. I don't see engine symmetry imposed as a rule, unless I'm missing it. And it might explain weird engine sounds, since the V6 would be composed of two V3s.

5.1.10 The crankshaft may only have three connecting rod bearing journals.

I think this puts a damper on that party.

It may have to do with the firing order, who knows, maybe two cylinders fire on one bank, and one cylinder fires on the other bank. Or maybe like a triple screamer(big bang engine) where each pair of cylinders on opposing banks acts as it's own big bang engine. Sort of like the Yamaha VMAX engine? Or the Honda VFR?

[1158]

What if instead of shorter length he is speaking of shorter height. Would that allow the entire PU to sit lower? Or are their regs stating where the PU height must be. I don't recall any. If you had a shorter crank throw there would have to be some way to still get the required stroke. Could a trick piston or rod do this?

I'm just trying to think way out of the box here, probably too far out...

[PlatinumZealot]

Everything on schedule. Lot's of testing and work...............

Also, Wazari, while you are here...

It seemed like you had some knowledge of the Mercedes "vortex exhaust" rumor. I think what it might be referring to is toroidal vortices, also known as vortex rings. Specifically, they might be inducing vortex rings within the exhaust manifold in order to better entrap heat within each exhaust pulse. Vortex rings are know for their ability to transport heat and gases across long distances, due to their self-contained, self-circulating nature. The specific type of flow I'm referencing is known as poloidal flow, although there are other types.

https://upload.wikimedia.org/wikipedia/ ... lierin.jpg

If a vortex ring can be induced after the exhaust port and made to traverse the length of the manifold before bursting into the turbine inlet, you might minimize heat lost to the manifold's wall. This satisfies the other piece of the rumor—that it was about maximizing heat retention.

https://youtube.com/watch?v=Sj9irzI-Pzw

Initially when I heard "vortex," my mind went to a helical vortex. But helical vortices tend to be open-ended and not self circulating. So, to me, it didn't quite satisfy the heat retention quality. I thought about the concept of self-containment a little more and started visualizing different types of vortical flow. Ring vortices seem to fit the bill. I have an illustration of the idea and hope to post it soon.

What do you think? Best of luck with preparations.

This is something new to me. Thanks for that.

The renault number from exhaust is extremely high. It would be very difficult. To keep that poloidal flow at a high and such unsteady speed i suspect. Remember the blown diffusers how difficult it was to make the vortex stay where the designers wanted it? Granted a big old spinning tyre was trying to smash it.. But i can imaging how difficult is is to keep your rolling poloaidal vortex and its subsquent followers in formation undisturbed in the exhaust pipe. That the vortext rolls perpendicular to the flow is the hard part.. What would stop these high pressure flows from collapsing it against the walls of the exhaust?

[PlatinumZealot]

What if instead of shorter length he is speaking of shorter height. Would that allow the entire PU to sit lower? Or are their regs stating where the PU height must be. I don't recall any. If you had a shorter crank throw there would have to be some way to still get the required stroke. Could a trick piston or rod do this?

I'm just trying to think way out of the box here, probably too far out...

He is talking about longitudinal length of the crank. Make the block shorter front to back.

[roon]

PZ- It's true. I have questions about how the pressure differential, or gradient, between pulses might want to tear a vortex ring apart. Consider that if the poloidal flow is moving from inside, forward, to outside, rearward, then the vortex will be climbing, or wheeling, its way across the interior of the manifold wall. In that context, perhaps the manifold wall is not so detrimental.

[PlatinumZealot]

The engine has a buffeting noise. It sounds like my project bmw m20 engine when its not idling right lol and it is a straight six engine.. So could be some clue that honda may indeed have an unusual firing spacing.

A buffeting noise also. My exhaust has no cats either so we could be hearing the "pure sound" from the engine undisturbed by the turbocharger.. So I think that the engine could be idling with the wastgates open. Sounds unnecessary but why not?

I won't dare to say it sounds a little teeny bit like diesel knock.. Tempting.. But.. I think it is more like buffetting as i said earlier.

[roon]

What if instead of shorter length he is speaking of shorter height. Would that allow the entire PU to sit lower? Or are their regs stating where the PU height must be. I don't recall any. If you had a shorter crank throw there would have to be some way to still get the required stroke. Could a trick piston or rod do this?

I'm just trying to think way out of the box here, probably too far out...

The crankshaft centerline has to lie 90mm above the reference plane i.e. the bottom of the car. Piston stroke is specified by the spec bore diameter & a swept volume value (1.6L) divided by six equal capacity cylinders. Crank throw length is implied in all this but not specified.

[Sasha]

Ford Flathead V8 like?(two rods sharing the same crank pin)
So more like a 120 degree V6 than 90 degree V6.
Will sound weird because it is like two separate I3 than a V6 in firing.

[Jerrycobra]

https://twitter.com/McLarenF1/status/831539885630689286

When i heard that clip, it instantly reminded me of this clip mclaren posted on twitter when they were testing at rockingham.

https://twitter.com/McLarenF1/status/786503350980341760

The idle sound from that RA616H is almost identical to that of this new engine.