mgeoffriau

iTrader: (7)

I accept this judgment. I signed up a few years ago for sports news (fantasy leagues). Works well for that, probably 80% of my usage is just for that. Other 20% is some people I find interesting or funny.

good2go

iTrader: (2)

Not that I'm making any judgements about it, but from time to time it occurs to me that Joe must have an inordinate amount of free time available.

Joe Perez

iTrader: (8)

Pfleh.

I'm just really brave / creative with Google search terms. And I keep a VM running on my work PC with TOR routed through PIA, so I can pretty much be immune from the typical consequences of searching for, well... the kind of stuff I search for on a PC at work.

In my job, there are short but frequent periods of boredom while waiting for some specific event to happen. I elect to use that time for the betterment and amusement of all those here at MT.

For instance, today I did this:



But not this:




Or this:

good2go

iTrader: (2)

...and truth be told, it is a noble act indeed!

z31maniac

Noble indeed. Those videos on the old school graphics are pretty cool.

Particularly interesting since I think I'm going to go back this fall and start taking some computer programming classes.

sixshooter

iTrader: (12)

Friggin 88 degrees here already. Getting hot to wear firesuits on the track with this high humidity. /done complaining

Joe Perez

iTrader: (8)

It depresses me somewhat to think that I came of age on the tail end of the original PC revolution, and yet failed to become John Harris.



At any rate...


Consider a two cycle engine, in which the crankcase is sealed and fitted with a conventional pressurized lubrication system. The inlet ports are fed by an external compressor (a turbocharger or supercharger), and direct-injection is used to administer fuel into the cylinder during the compression stroke, after the exhaust port has closed. Such an engine could be constructed with any number of cylinders, in any arrangement, and would combine the extremely high specific output of a conventional two cycle engine with the low emissions and durability of a modern four cycle.

turbofan

iTrader: (1)

Didn't you just describe a Detroit Diesel, except in a gasoline version?

Joe Perez

iTrader: (8)

I thought that Detroit Diesels had valves and camshafts, and produced only one power event per cylinder for every two rotations of the crankshaft?

good2go

iTrader: (2)

Isn't this basically what Evinrude is doing with their clean 2-stroke boat motors?

turbofan

iTrader: (1)

Interesting, I'd never looked this up before.


No wonder it's so inefficient. Exhaust is pushed out only by the incoming air rather than by the piston pushing it out. And there is a traditional-style valve in each cylinder as it turns out.

Joe Perez

iTrader: (8)

No.



That is typical of most two-cycle engines. They traditionally do not have an exhaust valve, however, using ports on both sides of the cylinder instead.

turbofan

iTrader: (1)

Indeed it is. Maybe it's just looking at the animation how it's some little tiny nozzle putting air in, and a little tiny valve letting air out.

It does seem it would be much more efficient the other way, with air flowing directly across the top of the piston.

Anyhow, why isn't anyone building an engine like you suggested, Joe? Instead of using the crankcase as the pump, use a supercharger and seal the crankcase.

hi_im_sean

iTrader: (3)

Because I kn ow how you roll
The Future Of Two Strokes And Dirt Bikes

still trying to find the original "white paper" on the technology as it applies to manly transportation.

Edit- This **** has been goin around all the forums since ive been riding, and no manufacturer yet has made plans to adopt it. Im waiting for injected 2 stroke to buy my next bike. cmon KTM!!!

turbofan

iTrader: (1)

I read some of that just now.

Sounds like corky's writing a little.

Joe Perez

iTrader: (8)

All else being equal, two cycle engines tend to produce considerably greater power per unit of weight / size than four cycle engines, which is why they are popular in dirtbikes, hand-held lawncare equipment, etc. Their principal disadvantages are fuel economy, emissions, and longevity, all of which stem from the fact that fuel and lubricating oil are introduced into the engine as a mixture, and some of this mixture tends inherently to escape through the exhaust port during the exintake process.



I can't tell you without revealing proprietary information about the upcoming HyperStroke engine.

hi_im_sean

iTrader: (3)

"Introducing the 2018 KTM Alpha Omega!"

Id be a sucker, Id buy.

hi_im_sean

iTrader: (3)

also
https://rideapart.com/articles/the-1...-you-cant-have

good2go

iTrader: (2)

From an article published back in 2008:

The 2-Stroke Of Tomorrow Is Evolving

Research continues by companies that have purchased license to use Orbital’s technology and GM, Ford and others have developed two-stroke designs of their own. Most of these engine designs utilize crankcase scavenging (crankcase pressure is used to push exhaust gasses out of the combustion chamber) and total-loss lubrication systems (oil essentially becomes part of the fuel charge). All designs scavenge the cylinders only with air, incorporate some means of varying the exhaust timing, include a multiple-chamber cylinder head and utilize air-assisted fuel injection.

French automaker Peugeot and its concept two-stroke engine incorporates a poppet valve that seals a pre-combustion chamber until fuel is delivered. Rather than use a separate air pump to supply the air-assist for injection, Peugeot has placed a second reed valve in the crankcase that allows air to escape into a chamber, which is then used to assist the air for injection.

Chrysler and Subaru have both developed two-strokes that stray further from the traditional two-stroke concepts. Rather than use the crankcase as the scavenging pump, they both use a belt-driven blower or supercharger to scavenge the cylinders. The crankcase remains a wet sump design like most automobile engines.

Transfer ports carry the air to the cylinder and the piston handles the valving of the ports. In Subaru’s design, an exhaust port in the cylinder is opened and closed by the piston, but just downstream of the port is a rotating valve that boosts the cylinder charge to more than atmospheric pressure. Air assist isn’t needed because the 1,000 to 1,200 psi fuel pressure rating automatically atomizes the fuel as it leaves the injector nozzle.

The biggest, most complex and heaviest of the conceptual automotive two-strokes is Toyota’s design. The engine is basically one of the company’s dual-overhead cam, four-stroke engines converted to run a two-stroke cycle. The camshafts run at crankshaft speed and air is delivered to the intake valves through a supercharger. Fuel is added through a high-pressure, direct-injection system. An in-line, six cylinder, 244 cubic-inch version of this engine is said to produce torque equal to GM’s 454 V8.

The motor vehicle industry has invested in a lot of two-stroke development and it’s not done. The success of the low emission two-stroke engines of today will suggest what will happen tomorrow. Will we see new two-stroke designs take over in the dirt bike market again? Will new two-stroke designs power ATVs again? Will Yamaha adapt its outboard HPDI system to snowmobiles? Who knows?

What I do know is that the new, clean two-stroke engines of today outperform the four-strokes in almost every category of performance with less weight and fewer complex, moving parts.


Given this was all 8 years ago, I'd fully expect nearly all conceivable designs have certainly been explored.
I wouldn't mind trying out that Toyota motor.

Joe Perez

iTrader: (8)

That's what bugs me- I hardly ever have any decent original ideas. Every time I think I've got something, it turns out that it's either already in production or has been conclusively disproven.

Except the automagic bomulator. That thing was ******* amazing (and deceptively simple.) Got an award and a huge bonus for it. But that was years ago, back before my brain got dumb...

Anyway, here's a website where you can play the Atari 2600 version of Halo: https://archive.org/details/Halo_Atari_2600