Car Engines...

[N19h7M4r3]

Well here is the thing... pistons have been around for a lot longer so the technology is much more advanced... but theoreticly wankels are much more efficient at their jobs... they just have a few design draw backs that are hard to overcome =)
so give "us" xD your opinion

PS: does anyone know how a diesel roraty engine would handle? since they run hotter that would kinda help with diesel combustion right? lol

 

[will_chellam]

Wankel engine - used in the spitfire, won the war.

 

[megamanx00]

^ good a reason as any .

Anyway Rotary certainly has advantages, but too many are simply comfortable with what they are use to, which is why pistons are more common. It's the same reason we use unleaded instead of diesel (or even electric cars), why there were zealous Intel Fan Boys when the P4 got spanked by the Athlon 64, or rabid AMD fans in the face of the i5 and i7.

 

[jitpublisher]

Well here is the thing... pistons have been around for a lot longer so the technology is much more advanced... but theoreticly wankels are much more efficient at their jobs... they just have a few design draw backs that are hard to overcome =)
so give "us" xD your opinion

PS: does anyone know how a diesel roraty engine would handle? since they run hotter that would kinda help with diesel combustion right? lol

You are right I would suggest. People are used to piston engines, and how they operate, their power curve, how they run.
The rotary engine is different, different power curve, simply runs and feels different than a piston engine. That is one thing an electric or hybrid has had to accomplish, they must "feel" like a gas/piston engine, albeit a very, very quiet piston engine.
People just were not comfortable with the the rotary, even though they could be made in theory to be vastly superior to a piston engine. Longer life, way fewer moving parts, light weight, better fuel milage, cheaper to maintain. They had some design problems to overcome, but holy cow, so did the piston engine. Their were plenty of those made that turned out to be complete duds over the years as well!

Remember the Volkwagon commercial where the 2 guys are talking, one has a hybrid and the other has a new volkswagon?
When they ask what their cars sound like, the hybrid guy kind of yawns out a bit of air "haaahhhhhhhhhhhh", and the volkswagon guy goes "VROOOOOOMMMMMMMMMMMM!!!!!!" You could also add to that that the rotary engine goes "hmmmmmmmmmmmmmm". Kind of boring you know........Mazda had a commercial back in the early 70's, if anyone remembers where they actually sang this little jingle, "piston engine goes boing, boing, boing, boing, boing, boing, boing, but the Mazda goes mmmmmmmmmmmmmmmmmmmm.........."

 

[amnotanoobie]

For now piston engines, a ton of R&D has already been done on it. But if there are some significant developments over at the rotary side, people might just change their tune. If somehow rotaries would have some distinct property that would make them an advantage in a hybrid car setup, then it would have a very big future ahead of it.

 

[jitpublisher]

My god, I can't believe it. What you cannot find on the internet these days, here is that rotary engine commercial, try not to die laughing when you watch this.....
http://www.youtube.com/watch?v=oHzeGEHWMjo

 

[ulysses35]

Wankel engine - used in the spitfire, won the war.

Ermm.... Sorry dude but the Supermarine Spitfire was powered by a Rolls Royce Merlin engine.... V12 / 23 litres not a Wankel

 

[jimishtar]

Wankel Rotary engine has only one BIG issue - 2 much heat. that is the reason why mazda rx8 has 2 smaller engines instead of single big one. at this time, the heat issue doesn't seem like being taken care of in the near future, simply because the piston engines do the job quite good. after all, i personally believe that till the time comes for rotary engines 2 become more attractive and needed than pistons, fuel reserves will be long gone, and electricity/hydrogen era will be the next best thing.

 

[N19h7M4r3]

Wankel Rotary engine has only one BIG issue - 2 much heat. that is the reason why mazda rx8 has 2 smaller engines instead of single big one.

are you telling me that a bugatti veyron has 16 small piston engines because 1 12L piston engine would just generate to much heat?

plus heat isn't a bad thing on its own... its like having organisms withstand 200ºc degrees of heat... is hot for us, but they seem to have no problems with it... if you develop an engine to work hot, it will just work hot...
plus as i said before this might be helpfull for diesel combustion as its even a better fuel then petrol or gasoline since it has more energy per litre
just to rememeber hidrogen on its own kinda "burns like any other" gaseous fuel... so it can work in a piston\wankel engine... (but i know you meant hidrogen fuel cell lol)
plus we have used vegetal oil can be used in diesel engine so if we increase our need for chinese fast food we might also be getting more fuel production...

 

[jsimeon]

What of Chrysler's attempt at the turbine concept.

 

[N19h7M4r3]

What of Chrysler's attempt at the turbine concept.

dont know much about turbine engines, but they are rotary engines... to bad i cant take the wankel out of the poll name

 

[jsimeon]

someone may get a kick out of this.

1964 turbine car specs

* 130 horsepower at 3,600 rpm (output shaft speed); 425 lb-ft of torque at zero rpm!
* Weight: 410 lb - 25 inches long, 25.5 inches wide, 27.5 inches tall (without accessories, which make the overall length 35 inches).
* Fuel requirements: what've you got? diesel, unleaded gas, kerosene, JP-4, others. No adjustments needed to switch from one to the other.
* Compressor: centrifugal, single-stage compressor with 4:1 pressure ratio, 80% efficiency, 2.2 lb/sec air flow
* First stage turbine: axial, single-stage, 87% efficiency, inlet temperature 1,700 degrees F.
* Second-stage turbine: axial, single-stage, 84% efficiency, max speed 45,700 rpm
* Regenerator: dual rotating disks, 90% effectiveness, 22 rpm max speed
* Burner: single can, reverse flow, 95% efficiency
* Maximum gas generator speed: 44,600 rpm
* Maximum output speed, after reduction gears: 4,680 rpm
* Exhaust temperature at full power: 500 degrees Farenheit.

http://www.allpar.com/mopar/turbine.html

 

[jimishtar]

plus heat isn't a bad thing on its own... its like having organisms withstand 200ºc degrees of heat... is hot for us, but they seem to have no problems with it... if you develop an engine to work hot, it will just work hot...
plus as i said before this might be helpfull for diesel combustion as its even a better fuel then petrol or gasoline since it has more energy per litre
just to rememeber hidrogen on its own kinda "burns like any other" gaseous fuel... so it can work in a piston\wankel engine... (but i know you meant hidrogen fuel cell lol)
plus we have used vegetal oil can be used in diesel engine so if we increase our need for chinese fast food we might also be getting more fuel production...

if u make 1x12L piston engine, once u start the car, the piston will blow away as far as the Moon, passing along the International Space Station. there is a mechanical limit to how big a piston&cylinder can be. + the bugatti has w16 engine just to show that i can be made W16, u can go 400 km/h with just v8. plus, heat issue with wankel is that it concentrates heat on particular parts of the block, leaving other part relatively cold. this heat concentration requires the block to be made from special materials, such as ceramics or some metal mix, which makes production expencive, which brings us back to piston engines being better.



to the other guys - wankel engine is different type of rotary engine (there are many rotary-type engines, this thread is about wankel).

 

[jitpublisher]

Yeah, we are kind of getting off base here talking about turbines. Although I guess they are a type of rotary engine, the priciple behind what makes a Wankel and and a turbine engine run are 2 very different technologies. A Wankle is still a 4 stroke, reciprocating engine. The reciprocation is just minimized to the extreme.

 

[jimishtar]

its more of a 3 stroke, actually.

 

[pjmelect]

I have been slightly involved with this idea which may be of interest to those of you interested in the future development of the combustion engine.
http://www.eurekamagazine.co.uk/article/2545/Flat-disks-make-ultimate-spring.aspx

 

[jitpublisher]

its more of a 3 stroke, actually.

Yes, now that you mention it and I think back to what the Wankel looks like, what it does for "strokes" is more like 3, they kind of overlap.

 

[gazfast]

Wankel engine - used in the spitfire, won the war.

Sorry Will, suggest you might want to check that, last i saw/heard, the Spitfire was powered by the Rolls Royce Merlin V12 piston engine.

a former boss had one in his boat, helped him source some parts out of South Africa.

don't mean to rain on your parade, don't even know you, please take as friendly comment only.

 

[Devastator_uk]

The piston engine is more fuel efficient

 

[ulysses35]

if u make 1x12L piston engine, once u start the car, the piston will blow away as far as the Moon, passing along the International Space Station. there is a mechanical limit to how big a piston&cylinder can be. + the bugatti has w16 engine just to show that i can be made W16, u can go 400 km/h with just v8. plus, heat issue with wankel is that it concentrates heat on particular parts of the block, leaving other part relatively cold. this heat concentration requires the block to be made from special materials, such as ceramics or some metal mix, which makes production expencive, which brings us back to piston engines being better.



to the other guys - wankel engine is different type of rotary engine (there are many rotary-type engines, this thread is about wankel).

Large pistons are not really viable on cars / trucks - but large ships have enormous diesel engines, some with pistons big enouhg to hald a man. The problem with large pistons in small numbers (1 x 12 ltr eg) would be a very rough idel / turn over.

Small pistons in larger quantities are best... Jaguar proved this with their 6 ltr V12... still rated as one of the smoothest engines ever made. F1 cars used to be 3.5 ltr V10's which was one of the best balanced high revving engines ever use in motor sports.

 

[jimishtar]

bigger pistons have better torque, higher RPM, something that big objects, like trucks and ships, really need. but check out how huge is the cylinder that hold a ship's piston.

 

[ulysses35]

Just a quick search on google :-

http://people.bath.ac.uk/ccsshb/12cyl/

larger the capacity of the engine the lower the RPM as a rule.... too much inertia / weight behind the moving parts for it to be truely effective.

Thought some airfcraft engines do have large capacities and high RPM. Aforementioned Rollys Roye Merlin reach 27 litres... 3000 RPM and just over 2000 HP

 

[jitpublisher]

Holy cow there are a few bad assumptions up there a ways^
The large engines in ships rotate very, very slowly. The parts are simply to big, if you spun a engine that big at 4000rpm it would explode like a bomb. Diesel and large truck engines run much slower than their smaller gas counterparts. How smooth an engine runs is NOTHING to do with how big it is. Those huge ship engines make a lot of noise, but they are amoung the "smoothest" running engines in the world. But indeed 1 thing they do supply is just an amazing amount of torque.

The spitfire, and many older planes, used Radial engines. Pistion engines with the cylinders configured in a circle around the crankshaft. They are air cooled, and each cylinder needs direct exposure to the incoming air, or it would literally melt in a short time.

 

[jimishtar]

Holy cow there are a few bad assumptions up there a ways^
The large engines in ships rotate very, very slowly. The parts are simply to big, if you spun a engine that big at 4000rpm it would explode like a bomb. Diesel and large truck engines run much slower than their smaller gas counterparts. How smooth an engine runs is NOTHING to do with how big it is. Those huge ship engines make a lot of noise, but they are amoung the "smoothest" running engines in the world. But indeed 1 thing they do supply is just an amazing amount of torque.

The spitfire, and many older planes, used Radial engines. Pistion engines with the cylinders configured in a circle around the crankshaft. They are air cooled, and each cylinder needs direct exposure to the incoming air, or it would literally melt in a short time.

+100 from me

 

[gazfast]

Large pistons are not really viable on cars / trucks - but large ships have enormous diesel engines, some with pistons big enouhg to hald a man. The problem with large pistons in small numbers (1 x 12 ltr eg) would be a very rough idel / turn over.

Small pistons in larger quantities are best... Jaguar proved this with their 6 ltr V12... still rated as one of the smoothest engines ever made. F1 cars used to be 3.5 ltr V10's which was one of the best balanced high revving engines ever use in motor sports.

and let us not forget the fabulous BRM V-16 F1 engine, 1500cc and 16 cylinders, plus overhead cams and four valves per cylinder, mechanical fuel injecion, no EFI, awesome.

Plus it was reputed to be reliably producing 400+ horsepower - in the 1950s.

In the 1980s Ferrari and Honda bult 1.5 litre V6 turbos good for 900 horsepower, and again this was when EFI was in its infancy.

All of tis is not to say the Rotary is not a bad design, but it is a limited application design...rotaries as a rule produce limited amounts of torque, but relatively high horsepower, at high rpm, making them a great racing engine, you are not limited to try and make the car driveable at 60-80 km/h, the designer can go for the big numbers, remember a Mazda (Wankel) rotary remains the only Japanese engine to win the Le Mans 24 Hours, Mazda also had big successes with roatry engines in Touring Racing.

however, if you try to fit a rotary engine to a large passenger car, then the lack of low-down torque is instantly a problem, you get a carwith prodigious thirst and a distinct lack of acceleration, although given its head on the highway it suddenly becomes a slightly better proposition, howevre very few people get to just drive 500-600 kilometres at a stretch every day in a passenger car, hence thepopularity of the pistone engine for every day use.

Personally, I am a huge fan of diesel passenger cars, we own a Peugeot 307 HDi, but in my job a I drive a large varietyof vehicles, and there are some monsters out there, the Mercedes-Benz S 320 is an eye opener, although it is even better whenfitted to the C-Class, lighter bodyfor same huge power/torque figures.

sorry, this is a little off-topic, but thought it might add to the general flow.