Honda Power Unit Hardware & Software

[roon]

Like the old Lancia rally motor, we discussed the possibility of using this for this formula quite a long time ago on here somewhere, if I can find it, so it'll be interesting if true.

I proposed a couple sketches along these lines a few months back.

viewtopic.php?p=737286#p737286

this presumably 'diagonally opposed' as tried by F1 Repco-Brabham and F2 BMWs (Apfelbeck) in the 1960s
the unreliable F1 RB860 32 valver of 1968 had type 50 'diagonal' heads (16 inlets and 16 exhausts) or the conventional type 60

diagonal head sequence going round the chamber - exhaust - inlet - exhaust - inlet
conventional sequence going round the chamber - exhaust - exhaust - inlet - inlet

Could also retain the E-E-I-I format, only rotated 90* from typical. Geometry question: will the diagonal arrangement permit greater valve area?

The Apfelbeck head is interesting. However, in the current formula, it could not be applied without modification.

5.1.9 Engine exhaust gases may only exit the cylinder head through outlets outboard of the cylinder bore centre line and not from within the “V” centre.

The Apfelbeck would need a recursive/reticulated exhaust runner to ensure legality. The regulations would not prevent them from doing other unconventional layouts:

-Vertical or "outside vee" intake runners (an "empty vee", as it were).
-Exhaust flanges between camshafts yet still outside the geometric vee.

It should be noted that none of Wazari's hints or claims over the year(s) have ever been connected to actual hardware or real occurrences.

[roon]

I assume for more swirl action in the chamber.

It would appear so. Interestingly for me, the Apfelbeck head didn't come up in the previous discussion. Only a general mention of BMW motorcycle cylinder heads, some of which have atypical valve arrangements, but only to allow exhaust and intake runners parallel to crankshaft centerline. No application of tangential runner entry there, but this Apfelbeck did. My thought process had led me to tangential intake runners, hence the sketches, which I thought was a pretty decent idea. As with many things ICE, someone already tried it 50+ years ago.

[dren]

Thanks roon, I was looking for something showing the Apfelbeck. The only way to achieve this would be some interesting exhaust ducting inside the heads to meet the regulations. One exhaust valve larger than the other, the smaller valve has the odd ducting.

[gruntguru]

I assume for more swirl action in the chamber. Don't some diesel engines use this configuration?

The ability to create swirl with minimal flow penalty is one advantage. More importantly, the design has more flow potential. The paired valves (eg 2 x inlets), being further separated than a pent-roof design, have less tendency to "shroud" each other. The ideal implementation would have downdraft ports (near the spark plug) which tends to favour flow down the cylinder walls rather than towards the other inlet valve disrupting its flow,

[PlatinumZealot]

I assume for more swirl action in the chamber. Don't some diesel engines use this configuration?

The ability to create swirl with minimal flow penalty is one advantage. More importantly, the design has more flow potential. The paired valves (eg 2 x inlets), being further separated than a pent-roof design, have less tendency to "shroud" each other. The ideal implementation would have downdraft ports (near the spark plug) which tends to favour flow down the cylinder walls rather than towards the other inlet valve disrupting its flow,

I think there is a scavenging disadvantage. Just visualizing the exhaust escaping to two opposing sides makes my head hurt.

Two valves on one side gives more tumble and there are a few videos out there from big car makers that illustrate how modern "trip" and tumble designs have proven to be optimal for direct injection engines. Though interesting i cant see Honda going to such a clumsy and heavy design just for swirl. It would be esier to have two different sizes of intake valves or staggered opening or something.

[Thunder]

Posts have been moved to the General Honda F1 Topic, some have been deleted.

Friendly reminder: This Thread is STILL about the technical Apects of the Honda PU, not General or Team Talk.

[dren]

I assume for more swirl action in the chamber. Don't some diesel engines use this configuration?

The ability to create swirl with minimal flow penalty is one advantage. More importantly, the design has more flow potential. The paired valves (eg 2 x inlets), being further separated than a pent-roof design, have less tendency to "shroud" each other. The ideal implementation would have downdraft ports (near the spark plug) which tends to favour flow down the cylinder walls rather than towards the other inlet valve disrupting its flow,

I think there is a scavenging disadvantage. Just visualizing the exhaust escaping to two opposing sides makes my head hurt.

Two valves on one side gives more tumble and there are a few videos out there from big car makers that illustrate how modern "trip" and tumble designs have proven to be optimal for direct injection engines. Though interesting i cant see Honda going to such a clumsy and heavy design just for swirl. It would be esier to have two different sizes of intake valves or staggered opening or something.

It might be for different valve axis angles that might require larger rockers.

[godlameroso]

The ability to create swirl with minimal flow penalty is one advantage. More importantly, the design has more flow potential. The paired valves (eg 2 x inlets), being further separated than a pent-roof design, have less tendency to "shroud" each other. The ideal implementation would have downdraft ports (near the spark plug) which tends to favour flow down the cylinder walls rather than towards the other inlet valve disrupting its flow,

I think there is a scavenging disadvantage. Just visualizing the exhaust escaping to two opposing sides makes my head hurt.

Two valves on one side gives more tumble and there are a few videos out there from big car makers that illustrate how modern "trip" and tumble designs have proven to be optimal for direct injection engines. Though interesting i cant see Honda going to such a clumsy and heavy design just for swirl. It would be esier to have two different sizes of intake valves or staggered opening or something.

It might be for different valve axis angles that might require larger rockers.

It also allows you to use a flatter combustion chamber, which is easier to model in CFD. Eccentric valve angles can give a chance to reduce friction with roller rockers.

It means they have a lot more confidence with the pre-chamber tech, and this design is to get more out of it. I wonder how much time they spent with piston and cylinder ring design, especially as this part is critical to not just power but the longevity of the ICE.

[roon]

Eccentric valve angles...

What do you mean by this?

[godlameroso]

Eccentric valve angles...

What do you mean by this?

Mo' diesel like, less pent roof, but not completely flat. Pro tip, CC shape can help or hurt your pre-chamber depending on pre-chamber design. There's a sweet spot where stuff happens the way you want it to.

[roon]

Eccentric valve angles...

What do you mean by this?

Mo' diesel like, less pent roof, but not completely flat. Pro tip, CC shape can help or hurt your pre-chamber depending on pre-chamber design. There's a sweet spot where stuff happens the way you want it to.

Sure, photos of the Merc engine suggest as much. I made some rough measurements a while back: viewtopic.php?p=737053#p737053

Do you mean eccentric in a qualitative sense, or in some geometric sense? To the rest of your statement: yes, things influence other things, and when good things happen that's good, which is good.

[godlameroso]

What do you mean by this?

Mo' diesel like, less pent roof, but not completely flat. Pro tip, CC shape can help or hurt your pre-chamber depending on pre-chamber design. There's a sweet spot where stuff happens the way you want it to.

Sure, photos of the Merc engine suggest as much. I made some rough measurements a while back: viewtopic.php?p=737053#p737053

Do you mean eccentric in a qualitative sense, or in some geometric sense? To the rest of your statement: yes, things influence other things, and when good things happen that's good, which is good.

A bit of both.

[gruntguru]

I assume for more swirl action in the chamber. Don't some diesel engines use this configuration?

The ability to create swirl with minimal flow penalty is one advantage. More importantly, the design has more flow potential. The paired valves (eg 2 x inlets), being further separated than a pent-roof design, have less tendency to "shroud" each other. The ideal implementation would have downdraft ports (near the spark plug) which tends to favour flow down the cylinder walls rather than towards the other inlet valve disrupting its flow,

I think there is a scavenging disadvantage. Just visualizing the exhaust escaping to two opposing sides makes my head hurt.

I disagree (unless you are talking about scavenge during overlap). . . and who cares about the efficiency of that flow regime? If you want more scavenge flow just increase the overlap period.
.

Two valves on one side gives more tumble and there are a few videos out there from big car makers that illustrate how modern "trip" and tumble designs have proven to be optimal for direct injection engines. Though interesting i cant see Honda going to such a clumsy and heavy design just for swirl. It would be easier to have two different sizes of intake valves or staggered opening or something.

I think swirl is more effective than tumble (tumble extinguishes rapidly near BDC compared to swirl). Its just that pent roof heads and chambers don't lend themselves to swirl - the tangential component of flow from a single intake valve is cancelled by the second intake valve. The Apfelbeck chamber is almost conical (even close to TDC) and will support swirl at any piston position.

[dren]

I've read also that heat dissipation around the valve seats is better with the I-E-I-E configuration which would help deter detonation and knock.

[etusch]

I found this after searching that Apple
https://historicmotorsportcentral.com/2 ... -head/amp/