Honda Power Unit Hardware & Software

[1158]

You could make an oblong-rectangular shaped valve. A big ole valve that is as wide as two valves but the same height as one valve. Technically it could be lighter than two circular valves if designed right. The challenge would be manufacturing the thing, not to mention a really funky valve seat. So that out of the way, how do you make the second valve work with TJI while being legally an intake valve now?

Well the regs state 2 intake and exhaust valves per cylinder. I would consider the prechamber as still being part of the cylinder so I don't see a prechamber intake valve being illegal.

[PlatinumZealot]

Are "double anchor" intake valves allowed? A sub-valve that telescopes out from the intake valve in order to control the prechamber...

[1158]

Are "double anchor" intake valves allowed? A sub-valve that telescopes out from the intake valve in order to control the prechamber...

The only regs I see about valves are:

5.1.8 Engines must have two inlet and two exhaust valves per cylinder.

Only reciprocating poppet valves with axial displacement are permitted.

The sealing interface between the moving valve component and the stationary engine component must be circular.

The last bit does rule out an oval valve though.

Could the entrance to the prechamber be in the valve seat? When the valve is open it would allow a small amount of air into the chamber then when the valve closes the chamber is sealed. What affect would the prechamber combustion have on the intake valve seat in such a setup. Would it burn the valve?

[ringo]

if i were to hazard a few guesses:
i don't think the valve seat is perpendicular to the valve stem due to the need to have a very vertical and straight intake run into the cylinder.
the intake valves in the cylinder are also different sized
the exhaust valves are also different sized.

interesting nugget about the jet combustion going to the walls first before ignition of the lean mixture.

[godlameroso]

Different sized intake and exhaust valves promote swirl. Starting combustion on the periphery means the final heat release is concentrated in the center away from the walls, as the flame front moves towards the center of the cylinder. This means less cylinder quench, less heat lost to coolant.

[MrPotatoHead]

I mean Honda made single coil springs that could handle 9,100 rpm and 400,000km of service back in 1999. I would not be surprised if they had valve springs capable of handling 13k for 7,000km 19 years later.

One of the biggest reasons for the massive power increases in the last 20 years in NASCAR and drag racing is the development in valve spring technology.
As an example pro stock engines can have valve lift of 1.2 inches and max rpm of 12,000. They don't exactly last for 7,000km though

Correct - and they didn't last 700km, or even 7km let alone 7,000km haha. They would have to inspect the valve springs after every run down the track. Of course that is why they dropped the max rpm down to 10,500 - to reduce costs.
One thing that is interesting though is that if you look at valve lift vs valve area / valve curtain area the F1 engines have very close to the same proportion as the Pro Stock engines. Gotta love physics.

[godlameroso]

Two valves vs 1 is a matter of weight more than flow.

How many engine departments have a fuel kinetics modeling facility? No that's something petrol companies have the money and resources to invest in, not auto manufacturers. Having a tech partnership with a large petrochemical company opens that up to you.

Engine guys are still trying to squeeze water from rocks trying to get more from a thermodynamics aspect. Fuel kinetics and quantum chemistry is where all the real gains are happening. You can't use machine learning to do this because no one has any data sets to train the machine. Data has to be gained experimentally because if you try to brute force calculate this your program will crash, guaranteed. Too many parameters too many unknowns.

[roon]

i don't think the valve seat is perpendicular to the valve stem due to the need to have a very vertical and straight intake run into the cylinder.

We're on the same wavelength there. I've been thinking about a similar approach. It presents a couple challenges: radial alignment in-operation becomes a necessity, and machining the seat means rotating the stem through a conic motion.

interesting nugget about the jet combustion going to the walls first before ignition of the lean mixture.

Was this mentioned? This thread is hard to follow sometimes.

[MrPotatoHead]

. . . a zero degree crankshaft
not impossible eg in a Honda F1.

Now that would be interesting. 50% of the bangs would be big ones.

Or 100% of them would be really big ones. Recall Wazari did elude to a "short" crankshaft last year, never specifying short in height, or short in length. Height-wise, the "shortest" crankshafts would be flat-plane and 0-degee. I don't know if exhaust frequency analysis bore this out or not.

The rules are quite clear on the number of journals the crank must have.

[roon]

Now that would be interesting. 50% of the bangs would be big ones.

Or 100% of them would be really big ones. Recall Wazari did elude to a "short" crankshaft last year, never specifying short in height, or short in length. Height-wise, the "shortest" crankshafts would be flat-plane and 0-degee. I don't know if exhaust frequency analysis bore this out or not.

The rules are quite clear on the number of journals the crank must have.

Yes, three conrod bearing journals. How does that relate to my quote? Throw orientation doesn't alter journal count.

[MrPotatoHead]

Or 100% of them would be really big ones. Recall Wazari did elude to a "short" crankshaft last year, never specifying short in height, or short in length. Height-wise, the "shortest" crankshafts would be flat-plane and 0-degee. I don't know if exhaust frequency analysis bore this out or not.

The rules are quite clear on the number of journals the crank must have.

Yes, three conrod bearing journals. How does that relate to my quote? Throw orientation doesn't alter journal count.

Just related to the "short" crank talk from last year that's all.
Forgive me I have been quite busy and I'm weeks behind on catching up

[roon]

The rules are quite clear on the number of journals the crank must have.

Yes, three conrod bearing journals. How does that relate to my quote? Throw orientation doesn't alter journal count.

Just related to the "short" crank talk from last year that's all.
Forgive me I have been quite busy and I'm weeks behind on catching up

No worries. Actually, the dubiously useful concept I presented last year to satisfy this wording had a short (length) single throw crankshaft that still incorporated three journals. Just image a journal that contains three stepped diameter changes, or simple circumferential cuts to delineate three bearing surfaces. Goal was to fit a coaxial MGUK in front of the crankshaft and within the block. This is 100% not what was occuring in that actual engines.

[MrPotatoHead]

Yes, three conrod bearing journals. How does that relate to my quote? Throw orientation doesn't alter journal count.

Just related to the "short" crank talk from last year that's all.
Forgive me I have been quite busy and I'm weeks behind on catching up

No worries. Actually, the dubiously useful concept I presented last year to satisfy this wording had a short (length) single throw crankshaft that still incorporated three journals. Just image a journal that contains three stepped diameter changes, or simple circumferential cuts to delineate three bearing surfaces. Goal was to fit a coaxial MGUK in front of the crankshaft and within the block. This is 100% not what was occuring in that actual engines.

It is an interesting concept for sure.
I'm somewhat surprised no one has tried to integrate the MGU-K in the block in just such a fashion.
The only reason not to would be that it would likely increase the height of the crankline / CoG in the block vs sitting alongside.

[roon]

I'm somewhat surprised no one has tried to integrate the MGU-K in the block in just such a fashion.
The only reason not to would be that it would likely increase the height of the crankline / CoG in the block vs sitting alongside.

I'd add that a spur gear connection would be lighter/more compact than a planetary gearset, as another reason against it, if a speed reduction and compact motor design is maintained. Seems you're implying a direct-drive K would need to be larger diameter motor.

[Tommy Cookers]

a direct drive K would be bigger torque/diameterwise and much bigger inertiawise than the present K and slower responding
and slower responding than the ICE - this would increase the gearshift time (the time at reduced torque)

for any given power an axially compact (pancake) K will be slower responding than the present long and slim type