While I was reading carb and intake mods and motorcycle carbs, I thought of my old dirt bike. Two stroke designs are very simple, just wondering if any ever existed beyond the very early days. With a 2.0L engine like ours, you could get 2X the HP easily. ...of course the trade of would be rebuilding the top of the engine occassionally and failing emissions. But hey, we do that anyway, right? : )
2 strokers don't have much of a torque curve. Don't need one on a bike that weighs 300lbs. Not so good on a 3000lbs car.
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lol yeah the curve is insane
no torque....no torque....no torque....ALL THE TORQUE RIGHT NOW WEEEEEEEEEEEEEEEEEEEEEEE!
Ah the fond memories of my first RD-350.
Yea a rd350 or 400 doesnt have much torque but new dirtbikes do. Old rd's didnt even have power valves. They also had terrible reeds that made the low end miserable. Plus now they have the technology of properly timed ports for an all around powerband.
One of the first Subaru's was called the Subaru 360 it was a two stroke 356cc motor,"360", Suzuki, Mitsubishi all had two stroke cars.
Think about it in order for 4 stroke motorcycles to compete witht the two strokes they have to give them double the displacement. Even with that difference in displacment they still only make 2 more hp and 5 more ft pounds of torque.
Check this article out you may see more two stroke cars sooner than you think.
http://www.findarticles.com/p/articl...28/ai_12485781
They even have a two stroke motor that isn't a total loss system for oil it has a crankcase with oil in it that doesnt get mixed with the fuel. The #1 problem with internal combustion engines is leakage and the valve-train.
Originally Posted by pimp86LX
300lb bike? How about a 40 ton train? http://www.looksmartsacramento.com/p...6/ai_n13629194
Torque isn't the problem. Keep in mind people regularly use racing/lightened flywheels which reduces torque.
** I stand corrected: torque is not reduced. A flywheel will only help maintain a consistent output ...or something like that.
Last edited by [email protected]; 12-07-2005 at 08:14 AM.
I did a little homework after I read the posts. I expected to get one or two replies, but it seems I'm not the only one interested in different ideas. Like anything else involing engineering, it's cost - R&D, market, etc.
The answer about torque is mostly right. So how does a 2 stroke move 40 tons? Beats the hell out of me but it ain't by revving the engine to 12K and dumping the clutch, lol. What I've read about auto applications is that a loosely designed 2 stroke is put in a car and the results are usually not so good. In the 60's, the Berkeley 500 was built for racing which had enormous output, but burned pistons or fouled points, etc on a regular basis. This is common for two strokes (any bike manual) and is another reason why they didn't gain popularity. While the design is simple, the components are more critcal so... what you get in a typical weedeater is cheap fabrication for a device that won't usually see more than a 100 hours of use. Compare that to a company that only develops 2 stroke engines for it's railway diesel engines and you have a much different outlook on market and R&D.
While torque seems like the obvious answer, the orginal reason was probably emissions. After finding about the train, it appears emissions have greatly been reduced over the years, just like the diesel. At this point, it's hard to see 2 strokes become popular in such a 4 stroke saturated environment (cars), but they still exist in certain niches where they flourish. While comparing apples and oranges, either one can always outperform the other given unlimited R&D and budget. It's like the ricer/muscle car arguement that goes on, and on, and on... To me a four stroke car is the obvious choice today, but that's like saying Microsoft is the O/S of choice. It's not like anyone has a choice really. It's what happened to work out at the time and what we've come to live with. Cheers!
2 stroke, supercharging, and direct in cylinder injection=the future
...at least before fuel cells and ultra high power density capacitors take over..imagine, the 900whp electric car, you'll see that, no doubt..
Last edited by Accordtheory; 12-06-2005 at 06:29 PM.
direct injection so you don't get fuel in the exhaust on the overlap cycle, of course. that's how 2 stroke diesels already work..
If you want to learn more about this , look at how the engines on huge cruise ships are set up. 2 stroke diesels running insane boost levels, like 50-70psi..
How's this for a question, why can't a diesel engine run on gasoline?
Last edited by Accordtheory; 12-06-2005 at 06:28 PM.
How could a flywheel possibly reduce torque. You're talking about inertia. Once your clutch is engaged, your car is faster with a lighter flywheel. That will show up on an acceleration dyno too.
I want to see 900whp ...parked in my garage!! : )
I noticed all the turbocharging. Pretty cool, but expensive obviously. Direct injection, 2 strokes, super/turbo-charging seems to have more potential, but what do I know...
I would think diesels can't run on gas for many reasons. For one, there is no true spark. Also, I think it would be too hot for the engine design. Never thought about it much though. Give me the answers!! : )
You're right. I'm talking about inertia... which manages torque. It doesn't effectively increase/decrease the inherent torque of an engine, but it stabilizes the output. A lighter flywheel will reduce the time it takes to accelerate, but a heavier one maintains a consistent output more effectively. So, off the line at a given rpm, a heavier flywheel will maintain the energy the engine has created better than a lighter flywheel. That was my point. I'm all about lighter flywheels and acceleration. : )
Diesels cant run on gas, there is no true spark because diesels dont need any heat initially (unless really cold, which the glow plug is there for). Diesel explodes when compressed, like an oil boiler in your house.
Its that 3geez.com addiction.
Did you see the 3 wheeler car on Discovery yet? It uses a front end like a bike, but has a 2-3 person cab which rotates at some point near the rear (up to 45 degrees). It looked like lots of negative camber and independent suspension, which would make the handling interesting to say the least. Can't remember if it was gas or electric.
I don't even have cable tv..ugh..
I would love for someone to give me a definitive answer on why a diesel "can't" run on gasoline.. I do have a couple of my own theories though as far as why an existing diesel can't run on gasoline, but I see no reason why a compression ignition gasoline engine couldn't be built, with the right technology. I think it would all come down to the injector, you would need to get the fuel out into the chamber extremely quickly because of the much higher rate of flame propagation as compared with diesel, but you could do some really awesome shit with this style of engine. Stratified charge combustion with over a 23:1 static compression ratio. Put that in a 5600lb denali, get 30mpg..
I Seriously believe that there are forces in the industry, car companies, oil interests, etc, that are holding back the advancement of technology for their own financial sake. Just look at the shit endyn was building in the 80s, they built pro stock engines that ran over 23:1 compression on race gas, and that trickled down to street engines in the form of cam and piston kits designed to raise the compression and burn the mixture only on the exhaust side of the chamber. (cam profile tailored to avoid piston to valve contact with the raised dome on the intake side. The raised dome would push the mixture into the exhaust side of the chamber) We Still dont have that on production engines. They're halfway there, adding 'quench area' in the chamber, (edelbrock's sbc 'e-tec' heads are a good example of quench with a flat top piston) but they haven't taken it the rest of the way.
one more thing.. I don't know if you know, but saab came out with a variable compression ratio engine years ago. Very simple concept, the cylinders pivot slightly on an axist adjacent to the bottom of the cylinders. I remember thinking that was amazing when it came out, but now I know that concept is obsolete..by lowering the compression that way, you lose the quench, actually increasing your propensity of detonation, while of course lowering your efficiency..
Electric cars are the future, I need to design that ultra capacitor, damn it..Batteries and their associated energy losses will always hold the electric car back. Fuel cells, ultra high energy density capacitors, and electric motors will be the combination for the next 100 years.
no, lol, certainly is not. they idle under 300, and usually run a little under 1000. they work by powering a generator which then powers electric motors in the trucks.
http://travel.howstuffworks.com/diesel-locomotive.htm
Thanks for the link snoopyloopy.
Absolutely agree about the industry being held back. I've heard all kind of stories as I'm sure everyone else has about inventions that were bought out or banned. Not a fan of politics, big gov, etc and that's probably the reason. It kills me up how foolish the SUV craze has become ...people paying $100 a week to take their kids to school and buy groceries. The gas/diesel 2 stroke efficiency might a "Myth Busters" episode? (Junkyard Wars is a great show if you havn't seen it.)
Here is an insteresting article: "If diesel engines are more efficient, why do most cars have gasoline engines?" http://auto.howstuffworks.com/question399.htm
It seems that most of these reasons can or have been overcome. Still we use gas...
Probably the biggest reason newer concepts haven't broken through is consumer demand. As long as people are still buying the same SUV's and new cars every year nothing will change. You are right about batteries and their ineffiency. A friend, electrical engineer, where I work was telling me the other day about a chinese engineer that has come up with a battery that apparently puts out 64V and last up to 8 times longer than a standard battery. Who knows how long it will take to reach the market and if it will be affordable though. Obviously that would benefit electric or hybrid cars, but what about all the gas/diesel/stroke/injection designs that would be better than what we already use?
firstly diesel engines work on the detonation principle, and secondly diesel fuel burns slowly, unlike gasoline when mixed with air becomes a bomb.
Ive seen the saab VCR engine white papers, its a very simple design, the CR is varied from 14.5:1 to 8.0:1 throughout the rev range, boost is provided by a lysholm supercharger driven 30% overdrive.
I think hydrogen cars are the future. After all, they dont pollute, and making the fuel doesnt cause pollution, unlike electric cars.
Its that 3geez.com addiction.
but a ktm 450exc does, and a couple of old 80's xr250s do to
4 stroke Owns 2 stroke
Accordtheory, it is my experience and belief that a diesel won't run on gasoline because gas lacks the lubricity for the injectors/pump/ring seal required for the engine to function. also, i think that gasolines higher resistance to detonation has something to do with it, as it is a fuel that's designed to burn, not detonate like diesel. an example of this is premium vs regular fuel. premium is composed of slightly more "light" ends of the petroleum "spectrum" than regular fuel which is closer to the "tar or heavy" side of things. premium thusly has a higher resistance to detonation and slightly less combustive energy per unit of volume than regular gas. Now look farther down the spectrum (towards the heavy end) and you find diesel, with far more combustive energy, and a way higher propensity for detonation. in fact, the quality of diesel is marked by Cetane rating, usually between 30-70. this is indicative of "wax" content. why? in winter the higher wax fuels will gel more quickly, so a lower wax fuel is used, however the higher wax fuels will give more power. I've heard that worn out detroit diesels that are burning oil make incredible power until they explode, because the engine oil being a "heavy" fuel burns with the diesel and adds a fair amount of energy to the whole process. summing up, gasoline is too weak, won't detonate easily enough, and lacks the lubricity to run a conventional diesel engine.
i hope some of this made some sense...
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Bosch is currently introducing the second version of thier direct injection gasoline system. This direct injection system will make a very high A/F ratio possible and create a much more effective combustion. In terms of regular gasoline engines this will be the future.
i hope they make a kit for 3geez
I don't think a diesel engine runs by "detonation". How can a gasoline engine get completely blown apart in a matter of seconds from that, and a cummins diesel in a dodge truck can go easily 200k miles? I don't buy that at all. I think it's just a matter of the injectors.
And to people who think diesel has a higher propensity for detonation than gasoline, you can't even Begin to run the type of boost and compression on a gasoline engine that you can on a diesel without encountering detonation well before the spark event takes place.
werd, anyone wonder why 90% of semis are turbo'd deisels?
diesels do actually run on the detonation principle, just try putting a burning match into a bucket of diesel, it will extinguish, (dont try it on gasoline). Slow burn, try throwing diesel on a red hot iron bar, (FIRE)
diesels have a two part combustion chamber one to start the fire and one to shove the piston with the heat (as you may know that compressing air makes it hot, diesels compress is to an extent that it becomes so hot it rapidly ignites fuel upon spray), and fuel is not introduced into the intake stroke, it is injected upon TDC at compression, that is also the reason diesels dont have a throttle blade, lean burn induces detonation.
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