Custom engine builders?

[jellyrug]

Here it is, it will blow smoke at anything else.

 

[piratediverjefff]

The AtomicAss,

It is already clear that a small cylinder is more thermally efficient than a larger one. Given both are running similar octane gas and similarily aspirated, a smaller piston crown and combustion chamber will probably be more thermally efficient for many reasons. But it's not so simple. More cylinders means more friction and weight, all big negatives to efficiency. Further, the added complexity and packaging problems of too many cylinders is prohibitive. I can imagine an 8 cylinder 1340 cc Busa but it would be quite heavy. Realize also that small pistons need high revs to get good power, which reduces thermal efficiency and fuel economy.

I can imagine a V6 motorcycle, in fact there are (or have been) engines like this already, or maybe even a V8. I think thermal efficiency would best come from using some of the heat energy typically wasted, like a turbo charger. I suppose it would be possible to have a V4 gas engine with 2 additional steam powered cylinders with the steam generated from the waste heat from the V4. But again there is the complexity and need to either carry a water supply or condenser system to recirculate the water for the steam engine. So I'm not sure there are many options here that offer big gains in efficiency.

Obviously a 2 stroke is the biggest pig when it comes to any kind of efficiency. A direct injected 2 stroke could work, as a smaller displacement 2 stroke can produce big power and direct injection would limit some of the inherent inefficiencies of a 2 stroker. 4 stroke is a good compromise. Increasing the strokes means more unpowered strokes. This can be overcome with more cylinders and offset cranks like the Yamaha R1. Adding cylinders and adding power pulses may help thermal efficiency but it will not be good for power. Also an engine like this would need higher rpms.

Truth be told 150 mpg is well within current technology in a 1340cc motorcycle engine. Better injection technology, dead cylinders (drop 2 off in low demand), and gearing could all make 150 mpg possible. The real ticket to thermal efficiency is running the engine at a constant rpm. This could be done with a CVT. The trick to gas mileage is going hybrid.

As for money, this would cost millions, not $10,000. If you want to see what developing and engine costs, watch the documentary on the MotoGP engine effort MotoCZ made.

Arch,

Any chance you could find/post me a link to that Moto CZ documentary about the GP engine?Tried a Google search but couldn't find it and would like to check it out.

Thanks bro,
Jeff

 

[Tony Nitrous]

Interesting thread.

Not sure what you'll get for your budget though.

Two Gen-2 Busa top ends on a aftermarket but not a one off,
bottom end (to make a V8) built by someone who knows their stuff
runs at around $35,000 for the basic package, and that's with all the
R&D / testing and prototypes already done.

Something unique ?
A couple of brand new Busa's wouldn't get you in the ball park with the guys who know their stuff.

 

[fallenarch]

Arch,

Any chance you could find/post me a link to that Moto CZ documentary about the GP engine?Tried a Google search but couldn't find it and would like to check it out.

Thanks bro,
Jeff

I found this but it is not in English.

 

[piratediverjefff]

Thanks Arch,a lot of videos to go with it and some good stuff(now I just gotta figure out what the hell he's sayin' ).

 

[TheAtomicAss]

The AtomicAss,

It is already clear that a small cylinder is more thermally efficient than a larger one. Given both are running similar octane gas and similarily aspirated, a smaller piston crown and combustion chamber will probably be more thermally efficient for many reasons. But it's not so simple. More cylinders means more friction and weight, all big negatives to efficiency. Further, the added complexity and packaging problems of too many cylinders is prohibitive. I can imagine an 8 cylinder 1340 cc Busa but it would be quite heavy. Realize also that small pistons need high revs to get good power, which reduces thermal efficiency and fuel economy.

I think this latter point is true only because low-displacement engines tend to also be low cylinder count engines. Basing my estimates on these charts of Torsional Output of Piston Engines, I'm guessing that a 5-stroke diesel 8+4 like in my doc would produce usable power at the very least in 'Busa territory, if not lower (4-banger car territory, perhaps)

I can imagine a V6 motorcycle, in fact there are (or have been) engines like this already, or maybe even a V8. I think thermal efficiency would best come from using some of the heat energy typically wasted, like a turbo charger.

This is the reason for choosing the 5-stroke design, to recapture what otherwise would be wasted in the exhaust in a traditional 4-stroke.

Truth be told 150 mpg is well within current technology in a 1340cc motorcycle engine. Better injection technology, dead cylinders (drop 2 off in low demand), and gearing could all make 150 mpg possible. The real ticket to thermal efficiency is running the engine at a constant rpm. This could be done with a CVT. The trick to gas mileage is going hybrid.

Having ridden a CVT, (this being a rubber belt-driven CVT, I understand there are other designs) I can say for certain it's not all that it's cracked up to be. It introduces sufficient waste friction to reduce fuel economy enormously. One of the flexible items on my list, is a transmission design pulled from the bicycle arena, (but which should be suitable for motorcycles if the design was beefed up), a 14-speed design that has approximately the same range as a typical manual transmission in a motorcycle or car.

 

[nosbig]

I think this latter point is true only because low-displacement engines tend to also be low cylinder count engines. Basing my estimates on these charts of Torsional Output of Piston Engines, I'm guessing that a 5-stroke diesel 8+4 like in my doc would produce usable power at the very least in 'Busa territory, if not lower (4-banger car territory, perhaps)


This is the reason for choosing the 5-stroke design, to recapture what otherwise would be wasted in the exhaust in a traditional 4-stroke.


Having ridden a CVT, (this being a rubber belt-driven CVT, I understand there are other designs) I can say for certain it's not all that it's cracked up to be. It introduces sufficient waste friction to reduce fuel economy enormously. One of the flexible items on my list, is a transmission design pulled from the bicycle arena, (but which should be suitable for motorcycles if the design was beefed up), a 14-speed design that has approximately the same range as a typical manual transmission in a motorcycle or car.

Don't know if you remember honda has already tried a ten speed transmission in the early 80's on there 900. Great idea but it just didn't catch on very well and only lasted a couple years

 

[fallenarch]

I think this latter point is true only because low-displacement engines tend to also be low cylinder count engines. Basing my estimates on these charts of Torsional Output of Piston Engines, I'm guessing that a 5-stroke diesel 8+4 like in my doc would produce usable power at the very least in 'Busa territory, if not lower (4-banger car territory, perhaps)


This is the reason for choosing the 5-stroke design, to recapture what otherwise would be wasted in the exhaust in a traditional 4-stroke.


Having ridden a CVT, (this being a rubber belt-driven CVT, I understand there are other designs) I can say for certain it's not all that it's cracked up to be. It introduces sufficient waste friction to reduce fuel economy enormously. One of the flexible items on my list, is a transmission design pulled from the bicycle arena, (but which should be suitable for motorcycles if the design was beefed up), a 14-speed design that has approximately the same range as a typical manual transmission in a motorcycle or car.

I think a lot of people don't take innovators seriously. I do and I admire people who think differently and are not afraid to follow their ideas. It sounds like you have this thought out and know what you are talking about. But you will need more than $10,000. You might try a sponsor or maybe something like crowd sourcing.

Good luck to you.

 

[FlatlandBusa]

Don't know if you remember honda has already tried a ten speed transmission in the early 80's on there 900. Great idea but it just didn't catch on very well and only lasted a couple years

I could actually see a 7 or 8 speed trans being useful but all not like the CB900's were with two shifters. 1 down 7 up would work for me!

 

[nosbig]

I could actually see a 7 or 8 speed trans being useful but all not like the CB900's were with two shifters. 1 down 7 up would work for me!

Most people would just shift it like a 6 speed. Would only shift to the high side in fifth gear like an overdrive.

 

[TheAtomicAss]

The 14-speed gear hub I mentioned a few posts above is the Rohloff Speedhub, which is a nifty piece of engineering. Unlike what you might be familiar with in derailleurs, the Speedhub has 14 non-overlapping gears, derived from a 7-speed + reduction set, with a range close to what a 27-speed would give.

 

[fallenarch]

Maybe with a dual clutch you could have 20 speeds but shift them electronically. So the rider sees 5 gears and the bike computer does the intermediate shifts?

 

[Don Hardcastle]

I have one thing to say.... Flux Capacitor.

I, of course, am just joking... I'm following this thread. It is very interesting.

 

[TheAtomicAss]

A clutch isn't needed except for startup. Many paddle-shifted supercars feature sequentially-shifted manual transmissions, where the PCM cuts spark or fuel (or both) for a handful of milliseconds while simultaneously actuating the shift. Considering some (or all? not sure) of said cars also use centrifugal clutches, I'd say they've figured it out well enough

I believe I recall hearing of such a device that could be fitted to the Busa, et al, for the purpose of drag racing.

 

[fallenarch]

Can a centrifugal clutch lock up well enough for drag racing?

 

[TheAtomicAss]

Yes, certainly. Even after 26k miles my Burgman 400 locked up strong at 15 mph very consistently, even with the throttle pinned.

However, a drag race with a CVT is pretty much a lost cause, due to the transmission loss (the belt does slip under high loads), so a race between two bikes of the same weight, with the same engine, one with CVT and the other with sequential gears would hands down go to the bike with sequential gears.

The same situation but a manual clutch vs centrifugal, on the other hand, would be much closer, with the manual only winning if the rider slipped the clutch at a much higher RPM, as the centrifugal would be locking up at it's set speed WITH NO ARGUMENT FROM THE ENGINE ALLOWED.

 

[fallenarch]

So what about a manual style clutch with computer control. Just flick the switch and the clutch lets the engine spin up to 5-6K and gradually engages at 9K and then locks up. you could control all actions through the computer. You could also include quick shift. Simple clutch system, centrifugal advantages.

 

[TheAtomicAss]

That's something that I've been mulling over. The torque-converter-based automatic prevalent in cars is an unholy mess of inefficiency designed to convert brake shoes into dust and gasoline into waste heat. (more so than the engine itself already does on it's own)

The engine I've described in this thread is a cut-down version of an engine that I'd eventually like to have in a car, and at one point I had considered starting my own car company. I may still do so in the future, but for now the automotive landscape is changing far faster than my ability to plan can keep up with. (And as an anarchist, I have no patience for government regulation) But I digress.

It occurred to me that not everyone has the mental wiring to handle a clutch. But how to avoid a slushbox? Computer-controlled clutch it was.

 

[fallenarch]

If you are starting a company why start with an IC engine at all? Electric is simpler and i presume more efficient. It seems the big issue there are batteries and having to burn off excess power in resistors to control the output. I thought maybe somehow split the power between a generator and the drive train so excess power can be recycled rather than converted to heat. I don't think there has been a general rethinking of the car around electric power. Seems most are electric power adapted to a traditional chassis

 

[jellyrug]

So what about a manual style clutch with computer control. Just flick the switch and the clutch lets the engine spin up to 5-6K and gradually engages at 9K and then locks up. you could control all actions through the computer. You could also include quick shift. Simple clutch system, centrifugal advantages.

You don't need a clutch, or a torque converter. Pretty easy to do, technology already in use but current focus is performance together with economy and efficiency, the latter two taking priority.