Honda Power Unit Hardware & Software

[Craigy]

Definitely no "piston slap".

I would like to explain what I was thinking about when I suggested it sounded like that to me.
I'd describe it as a clattering noise; the sort of thing you get when the crankshaft is precisely in line with the centre of the top of the head as opposed to offset some small amount. It's an annoying adjective, clattering. It's not a word I want to use in relation to a piece of mechanical jewellery.

In terms of the noise, I was also thinking of something I was reading about the other day.
BMW recently started publicising details of what one might describe as 'intentionally imperfect' bores on some of their diesel production engine cylinders (imperfect - as in, not a geometrically perfect cylindrical shape).
Their design is instead to form hone the bores such that they are a very gentle "bottom of cone" section instead, which copes better with thermal stress than a straight cylinder (essentially, it stops the piston from being exposed to conditions at the top and bottom of cylinder, with their opposite thermal stresses, from having to be in the same material at the same diameter - loose at the top and tight at the bottom or vice versa).

In F1 there is a rule about bore sizing (80mm, from memory).
Is there a rule or clarification about where on the cylinder this is measured (and it would presumably have to be a cold measurement!), or about what the tolerances are through the travel of the bore that deviate away from the 80mm?

Is it possible that there is some deviation designed into the cold engine which is useful once hot, or non-cylindrical honing of these coatings?

(NB. I'm not asking for answers from Wazari-san as it would be impolite to do so - these are more thoughts for the group to ponder and/or shoot down in flames as applicable).

[Thunder]

So after hearing that Clip 3 Times on 3 different devices (at first i thought my Headphones died ^^) my first reaction were the exact words as the Renault answer to that Video: (yes i realise it's because they posted their fire up Video too, but the comment was fitting) https://twitter.com/RenaultSportF1/stat ... 4726253572 But then i thought "Why on earth would the release a Video where the new Engine sounds unintentionally like a Sack of Nuts? Was it literally the First Time that PU Spec fired up with a super base map just to keep the Engine Turning? Are they trying to fool us? Is it just a super bad Microphone?"

But then hope took over. So after all this talk about aggressive Design Elements i thought "well maybe they found something new and that's just what it sounds like, it's just idle after all."

So here i am confused, a little calmed by Wazari's comments, hoping Option 2 is true.

btw that Turbo spooling down at the End of the Video is some sexy stuff. ^^

[Frank_]

that spooldown sounds like my unequal length mani test (subaru-esque cyl,s 1 and 2 delayed in a loop)

[Abarth]

If you want a 3 cyl. engine, just drive the camshafts at 1/4th of the crank speed and shape the cams accordingly.

And if you do this on one bank only, you'll get a 4.5 cyl engine

[FW17]

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

[Farfar]

So if total block is shorter than 2016, ¿Could the turbo be out of the V with the same length than last year? How shorter could be the new block?

[Andres125sx]

OMG, winter is boring, isn´t it? One short video showing only sound of a PU fire up at idle, and instantly three pages of speculation



Mr. Wazari, in my humble opinion your posts are the perfect example of how companies spokespersons should talk to media. Instead of the usual BS they always throw, your posts always give some new data, idea, concept to wonder about, but without saying anything specific wich may be a company secret, so you keep us entertained without compromising your company

Great job, thank you for your contributions =D>

[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...

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.

I vaguely recalled something about crank centerline but couldn't remember if I was remembering right, if that makes sense.

[PlatinumZealot]

OMG, winter is boring, isn´t it? One short video showing only sound of a PU fire up at idle, and instantly three pages of speculation



Mr. Wazari, in my humble opinion your posts are the perfect example of how companies spokespersons should talk to media. Instead of the usual BS they always throw, your posts always give some new data, idea, concept to wonder about, but without saying anything specific wich may be a company secret, so you keep us entertained without compromising your company

Great job, thank you for your contributions =D>

Andres.. This is strange yes but it could be japanese media culture. Watching japanese produced car videos and magazines as a kid i was glad for the full explanations.
Even the other day while i was designing a ultrasound interface detection system for underwater i had to browse thru the japense side of youtube to get a good explanation on how to make the sensor follow the blanket. The video was in japense, but the diagrams and animations were so descriptive i got my answer. I find they are great at customer and fan engagement!

[roon]

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.

AFAIK current engines are already designed this way. Crank is regulated to have three throws. Two pistons per throw, each throw arrayed 120° from the other.

godlameroso- You mentioned firing sequence, perhaps they have an uneven throw arrangement i.e. not arrayed at 120° intervals. A flat plane three-throw, or something weirder. A two throw crank might still be legal depending on interpretation, or inclusion of a dummy throw.

[roon]

So if total block is shorter than 2016, ¿Could the turbo be out of the V with the same length than last year? How shorter could be the new block?

The block would be shortened, approximately, by the thickness of one connecting rod. Maybe 20-40mm range. If coplanar knife-and-fork rods are being used. You end up with a more compact block, structurally symmetrical (load paths from transmission to monocoque), and symmetrical loading of the connecting rod journals. Seems ideal.

[PlatinumZealot]

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.

Good work. This is a clue that things may no be as different as we think when it comes to crank design and ignition spacing.
I feel it's just the wastegates that are open... could be to test them or warm them up or something to that effect.

[glenntws]

Hey guys,

I'm new in this Forum but since this discussion is very interesting, I thought I could also talk a bit with you.

First: I'm very sure the engine was running in a Controller cylinder shutoff with one cylinder active on one bank and two others on bank 2. I'm also pretty sure , the distance between the ignitions was 300° - 180° - 240°. I took a look at the sound file in audacity and here's a little part of it colored by me:



The yellow colored is the ignition on bank 1, the blue and green ones are on bank 2 I think.


Second: I'm also sure that the idea of the pistons without offset won't be the right one. This way of rod design won't be good at all for the high pressures. Additionally: The crankshaft will have to have the same length either way, and a cylinder offset will only help in regards to the intake System. The 20-25mm, which they lose lose from offset cylinders won't help much at all when looking at the placement of the turbocharger.


Third: While everybody thinks that TJI will come to the Honda engine, I think I have a idea of how this System could look like. I made 4 little Sketches which could explain the System fairly good.

Intake stroke:

Mid-compression stroke:

End of compression stroke:

Start of ignition:

Now, I will explain you why I think this should work. At first, thanks to this design, all the requirements by the fia are fullfilled.
So, once the intake stroke starts, you get a pretty high amout of tumble in the chamber, which will - because of the gas Forces - clear out the prechamber. The prechamber has a ~5mm wide opening at the bottom, which is almost completely (0.1-0.3mm distance) closed at TDC. The prechamber also has several little holes all around. which can force the ignition arcs into the main chamber.

Mid-compression stroke, the engine will start injecting fuel. Since the piston has this pinnacle at the top (which also closes the prechamber), the fuel, if it's shooted in a narrow angle onto this Point, will automatically form a rich cloud of fuel-air mixture directly under the opening of the pre-chamber. At the end of the compression stroke, this very rich cloud will partly be forced into the pre-chamber, while the main chamber will retain the two tumble motions on both sides.

When starting the combustion, the movement in the prechamber will go down with big force thanks to the droplet-replicating shape. Since the main-opening is closed, fire arcs will go into the two chamber parts and will induce a combustion in the motion of the two tumbles, which in turn will make sure the combustion will happen as clear as it can.


Keep in mind, that these sketches are made pretty fast. I just think this is a way, Honda could do it like.

I'm no Student in mechanics or thermodynaics nor do I work in this sector (finishing high school right now in Germany). However, I'm working on a engine since 2 years. While it uses HCCI, I think the (pretty big) amount of knowledge I gained could help to find out at least a little bit more about the Honda engine

[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.

AFAIK current engines are already designed this way. Crank is regulated to have three throws. Two pistons per throw, each throw arrayed 120° from the other.

godlameroso- You mentioned firing sequence, perhaps they have an uneven throw arrangement i.e. not arrayed at 120° intervals. A flat plane three-throw, or something weirder. A two throw crank might still be legal depending on interpretation, or inclusion of a dummy throw.

What I was saying is that there is no offset to pistons(everybody knows it must be a three throw)That is where you make the block shorter to make up the space for putting the compressor out of the V. So 2016(compressor in V)and 2017 PU(compressor out of V) could be close to the same overall size.

[dmjunqueira]

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

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