Rather perplexing...

http://world.honda.com/HRC/download/dl/wp01_1024.jpg


It's like a v8 with the pistons paired. Anyone have any info on wether this is real/what it's used in?

it's real. but it's not a V8.

this is honda's new engine design, the oval pistons apparently offer massive power gains over round ones. it was a design created by hoda's racing motorbike department about 30 years ago, but machining then didn't allow it to work very well, but with new technology research into it has continued.

Looks rather funky, thats a lot of piston surface area.

Got any more details?

http://world.honda.com/history/challenge/1979pistonengine/index.html - info about the original version, on the're '79 race bike.

http://world.honda.com/history/challenge/1979pistonengine/img/pho_02.jpg (http://world.honda.com/history/challenge/1979pistonengine/photo/03.html)

that's the piston and twin rods.

at the time Honda were totally dominating F1 too, and upon seeing this development in race bikes, oval pistons were banned from F1, although they had never even been tested for it, the FIA banned them to prevent Honda from giving themselves a futher lead above the competition.

apparently, the reason this design is so much better than round pistons, and offers better potential power is down to the number of valves and the little wasted space between them, this allows much better intake/exhaust flow, and it also allows more volume to be flowed too.

in tests the oval piston engine was also able to rev up to 22,000prm.

Honda made about 300 road bikes with this engine, it was the 750cc Honda NR.

Hope that was of some help :)

I always wondered why the FIA rules stated pistons could only be round. I'm thinking, as opposed to what? The truth is revealed. Good info.

you said they're putting more research into them, any info on recent developments?

...and people wonder why I would defend the claim that Honda is just as engineering/racing based as Ferrari ever was. They just happen to also make cars for the average/every day man.
Way before Mazda's rotaries were banned from Le Mans, Honda were banned from even thinking about this in an F1 car.

This is in part why I want Honda to do well in F1.

it looks like it is meant to have 8 valves per cylinder...
thats a lot, and a bit overkill.
even for a honda.
:)

i guess the oval shape distributes force better in a downward motion and wastes less in friction or something like that.

thats odd.

honda did produce a bike, the NR500 and later, the NR750. The GP rules back then, didn't allow any cc advantages to 4 strokes, and honda has always been very fond of 4strokes. So they had to make a 4stroke that would compete with the same cc 2 stroke, which is a very difficult challenge.

Eventually rev'ing to 19.5K RPM's, making 135hp, they did get it to compete, power-wise, with the 2 strokes, but it was too heavy and the bulkiness of the engine made it difficult to mount in a bike optimally.

of course, these days, almost all of the bikes are 4 stroke in the GP races, since they started allowing 4strokes a cc advantage. Last couple years it was 990cc's, and honda was dominating with a V5 engine, making 250ish HP. The rules changed for this year though, dropping the cc's down to 800. But from what has been shown so far....the 800's won't be much slower than the 990's were. Honda went with a more traditional V4 for the 800cc engine.

V5...

how does that work
two on one side three on the other

...

This is in part why I want Honda to do well in F1.


Its the reason Im driving my 2nd Honda, and when it does will most likely replace it with a 3rd.

V5...

how does that work
two on one side three on the other

yup.

in the case of my car, which is a narrow-angle V5, there is one cylinder bank, but the pistons are not in line, there are two off to one side and three off to the other.

yup.

in the case of my car, which is a narrow-angle V5, there is one cylinder bank, but the pistons are not in line, there are two off to one side and three off to the other.

thats not really a V5, more like an offset or staggered I5

The honda is basically a V4 with an extra con rod journal in the center. They haven't released the exact details, but its believed that the 3 cylinders on one side are smaller diameter than the rear two.

They are also fired in a "big bang" patern, clustering all of the power strokes in small amount of crank rotation.

there's pics of the crank floating around on the net

thats not really a V5, more like an offset or staggered I5

according to VW, it's a VR5 (vee straight 5) the cylinders aren't in line, so it's a V, regardless of it being a single-bank engine.

its not a very good picture, and it might not work here....but here's the crank http://www.gizmag.com/pictures/6262_3100643522.jpg

more pics at http://www.gizmag.com/go/6262/gallery/

Scroll to the bottom

according to VW, it's a VR5 (vee straight 5) the cylinders aren't in line, so it's a V, regardless of it being a single-bank engine.

http://www.motoczysz.com/main.php?area=news_view&art_id=31&p_id=13&return_path=news

I guess you'd call this engine a V4 then. Its a twin crank engine also, btw, cranks rotate in opposite directions. Another GP bike

after doing a search on the VR5 (I'd never heard of it) you are right, its a V5. From your discription, I thought you were discribing something more like what I posted above

now big bang engines are pretty cool.
i kinda wonder who was cracked out enough on caffine and sleep deprivation to think of that.

nothing too difficult about MAKING a big-bang motor, just requires different cams....what was perplexing was the REASON why it worked so well.

The thing that got engineers thinking so hard about it, was why relatively underpowered V twin race bikes were constantly beating the I4's on the track. The V2's couldn't match the I4's on the straights, but the V2's would consistantly get away with earlier full throttle coming out of corners, that the I4's, if they attempted the same level, would lose traction and high side violently.

So some smart cookie started looking at the dynamics of traction on a milisecond level. The simple question was, what causes traction loss? Its not just the power, obviously, as the above example shows.

But when you graph the individual power pulses between the two engine designs, not too shockingly, the V2's power pulses are half as often as a traditional I4. What this created was time for the rear tire to recover between pulses. Where as the I4 hits so frequently, the tire couldn't recover, and would cause a chain reaction that would make it step out.

So they made the I4 (and V4) to match the V2 closer in power pulses. 1 & 4 have the same power stroke together, ie, they are basically the same cylinder, working in unison. Same for 2 & 3. Same power, but completely different sound and traction quality. But the reliability suffers severely. The cams were a major problem, because its opening too many valves at once, lots of cam chains were breaking and cams snapping in half from all the stress. The load on the crank is much harder too. Even the chain and sprockets take a lot more abuse because of this.

Some of the newer ideas on this (which I assume was partially why honda went with the V5 originally) was to make "little bang" engines, where the pulses are slightly more staggered to spread it out just a little bit, to increase longevity

well thats what i was thinking...
if you have an I4 crank, all the crank parts will be split by 180*
in an I2 they are on the same side.

why not have a big bang I4, but instead of having them all on the exact same side, spread them out by 10 degrees or so.

less stress in one shot.

i guess thats what a little bang is tho...

too bad someone else thought of it first.