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Discussion in 'Technical and Troubleshooting Torque' started by Ljiljan, Jun 4, 2012.
id put anything in a bike,
including a diesel, as long as it ran.......
but i beleive that this will be prohibitively expensive and turn out to have a major flaw....
otherwise like he said, evinrude and mercury would be usuing this desighn or simmilar.
looking at what i understand of it (addmitedly little) it seems like it has more moving parts/potential to fail, as well as increased maintanance.
but if it brings back two strokes... im for it.
especially in a v-twin (my favourite engine desighn to ride - in theory its the rotary)
Honda is in love with 4 stroke engines. They love complexity for the sake of complexity. They are basically the reason 2 strokes disappeared from GP racing. And then street bikes. The other manufacturers basically followed suit. The problem is that Japanese manufacturers are extremely reluctant to build bikes that are a bit different, other than Honda, who once again build weird @rse sh!t simply for the sake of it. As noted, other companies, non-Japanese, non motorcycle, are already using this technology with great success. I reckon it's only a matter of time before someone uses it in a bike. I'm pretty certain KTM are still quietly developing their own version of it, but I'm guessing they are waiting for the right time to let it loose. Another problem is, that motorcyclists think that they are rebellious, non conforming and free thinking, when in reality most of them are sheep following the leader.
So what we have is the largest and most cashed up manufacturer who could afford to use and further develop the tech, but have no interest in doing so.
Thats how I see it. Could be wrong though
I think the biggest problem with reintroducing a 2 stroke today would be emissions standards, especially California's or the new EURO-5 (I think we're at 5 now?)
Hmmm, so the point of this engine is principally that it doesn't have the emissions of normal two strokes.
totally missed the point their mate. 2-strokes have high emissions primary because of the oil blending. Secondarily because fuel finds it's way into the exhaust.
Direct injectin solves the second problem and there are a couple of ways of solving the first.
This engine looks like a variation on a stepped 2-stroke. In this case each piston pumps itself up, rather than a neighboring cylinder doing it.
2-strokes will probably be the last incarnation of the internal combustion engine, but they will look different to the current fare.
So what about the Orbital developed stroker that was supposed to solve all the problems 20 years ago? Ford (in the UK) were very interested and provided a lot of backing for it but it still sank without trace.
In the large the Orbital proved overly complicated and unreliable.
Apparently some of the technology used in the direct injection was utilized and has found it's way into modern vehicles.
Unfortunately the whole orbital affair has made vehicle manufacturers adverse to new engine types. The limited success of the rotary wouldn't have helped either.
From memory, Pat, there is a cross sectioned orbital sitting in a dusty corner of the Motor museum in York.
Is the Orbital engine the same as the two stroke that Orbital developed that got put into a number of Ford Fiestas? I've always assumed they were different designs, hence my reference to Orbital designed rather than referring to it as the Orbital Engine. Happy to be corrected on that though.
Had a bit of a small world experience with the aforementioned Ford Fiesta development mules. Way back in the early 90s I went to an IMechE talk in the UK on this wonderous new two stroke that Ford UK were backing. Presentation of lots of photos of modified Ford Fiestas and whatnot. Promptly went to the pub and forgot all about it (hence my inability to recall tech details).
Fast forward a decade or more and I get a job with the Vehicle Standards branch of the Dept of Transport in WA. Amongst other things tucked away in a shed in Welshpool is a display of a cutaway car demonstrating areas of a vehicle covered by the ADRs. What should it be but one of the Orbital/Ford development mule Fiestas with the engine taken out and donated to the Guvmint, possibly in return for lots of emmissions testing contracts .
Bit daft really, given that the Mk3 Fiesta was never sold in Australia and needs significant mods to comply with the ADRs :twisted:.
I haven't been to the York motor museum for a while. Maybe I should.
I'd be surprised. I don't see anything there to make it significantly more complex, or significantly more expensive than current NTS. It should certainly be considerably cheaper than a 4T.
At the moment the single is still in prototype phase, the twin barely. There is a bunch of studies going into it at the moment. Won't be ready for a commercial market for a few years is my guess.
You can count them, there's 11. A normal four stroke engine can have as many as many as 10 times that.
edit: not quite accurate, but not far off.
One thing I don't understand is how they think their v-twin will be low on vibration compared to other v-twins. Primary and secondary vibrations should be pretty much identical.
The claim was it can be a practical 2-stroke v-twin and be the only 2-stroke to share the vibration characteristics of all v-twins. I can't evaluate this claim ('cause I don't know engines).
A similar argument is present in other documents.
ok, so the claim in the link is that the pistons move more like a 4-pot. Although things are moving in different planes, at least they aren't moving up and down at the same time.
yeh, that's the thing. All V-twins (4T and 2T), by virtue of running on the same journal, run out of phase, creating a balance - ie, TDC to BDC or close to.
Honda had a working prototype, 2 stroke engine that made more power than an equivalent 4 stroke, with half the emissions and fuel use. They raced it in the Paris Dakar in the late '90s?
Worked a little to well and Honda buried it... Company politics and they have spent much to much money on 4 stroke development...
I can't for the life of me remember the name of the thing.
That more or less became the DiTech that Aprilia used in at least one of it's scooters (the SR50, I think). It might have found it's way into some outboards too.
The emissions problem remains that oil gets burnt in the combustion chamber, even with the better efficiency the tech offers.
As I recall, the Orbital company couldn't attract interest or investment in Australia, so they went offshore. The direct injection method might have been the inspiration for the similar system finding it's way into four-stroke engines of late, which has benefits.
As far as their claim that four-stroke V-twins have vibration problems because the pistons move up up and down together - WTF??? A 90 degree twin has perfect primary balance because one piston is stopped at the top or bottom of it's stroke when the other is full speed, midway at the middle of it's own stroke, thus cancelling the primary vibes caused by a piston accelerating and decelerating. Sharing a crankpin doesn't alter the fact that the cylinders are 90 degrees apart (half the single stroke) in their respective cycles, but it does narrow setup and reduce side to side rocking. There is the matter of whether both cylinders fire on the same crank rotation (lumpier) or alternate ones, but that's a choice of the designer.
It's only almost true of a twin like a Harley, which is more like a big single split 45 degrees, and that's done that way on purpose to give the sound and feel that it does.
Sorry Wayned, that's what I meant. Got confused watching the animation.