New type of Car engine

[Mega]

http://www.msnbc.msn.com/id/42460541...ce-innovation/

Hmmmm very Wankle-ish

[oddlots]

Re: New type of Car engine

Nice find Mega.

[c1ue]

Re: New type of Car engine

Interesting, though it should be noted that this engine isn't to replace a car's internal combustion engine.

As far as I can tell, it is intended to replace the electric generation capability of internal combustion engines.

So really it is a new form of gasoline powered electric generator; the car still needs a standard electric engine.

And in turn, assuming I am correct, the wave disk generator really is competing against fuel cells, diesel generators, and so forth.

This is still a very useful invention, though it should be noted a significant portion of the efficiency delta vs. a convention car is due to friction losses in transferring energy from engine to wheels.

A diesel engine, for example, can have over 50% efficiency converting diesel to kinetic energy - but this doesn't translate into 50% of the energy of diesel fuel going into the wheels.

[Ghent12]

Re: New type of Car engine

This is supposed to be an ARPA-E project. That got me interested in looking into current DARPA projects, and some of them are pretty freaky. The insect mind- and muscle-control devices are disturbing, among other descriptions.

The current intended application for this wave disk generator is to make a gasoline-powered electric generator, but it is entirely possible that this will be adapted for use in more traditional, non-hybrid vehicles.

[cpnscarlet]

Re: New type of Car engine

A diesel engine, for example, can have over 50% efficiency converting diesel to kinetic energy - but this doesn't translate into 50% of the energy of diesel fuel going into the wheels.

50%??? Oh really? Carnot here doesn't know fact from friction.

eta max=1-(Tc/Th)...Found a ceramic engine block, have we????

[Jam]

Re: New type of Car engine

50%??? Oh really? Carnot here doesn't know fact from friction.

eta max=1-(Tc/Th)...Found a ceramic engine block, have we????

50% efficiency requires Tc/Th = 1/2. If Tc = 400 K (note that water boils at 373 K, so I am being generous), then Th = 800 K to get the required efficiency. Melting point of tungsten is 3695 K, so tungsten engine block would do (no need for ceramic).
However, more importantly, I heard the guy talk about shock-wave as a part of the cycle (didn't get the name of the cycle itself--anybody got it?). Shock wave implies non-equilibrium dynamics. The efficiency of Carnot cycle--and the maximum efficiency of a heat engine eta max=1-(Tc/Th)--is obtained assuming thermodynamic equilibrium at every point of the cycle, therefore I don't think it can be directly applied here.
See also more details on the operation of the engine here http://www.newscientist.com/article/...in-a-spin.html

[mfyahya]

Re: New type of Car engine

It doesn't seem to have the seals which are a problem with Wankels.

Weight seems very low, so this could be couple with a bigger battery to provide low end torque for a longer range than Priuses.

Also looks useful for constant rpm applications such as ships, generators...

[cpnscarlet]

Re: New type of Car engine

50% efficiency requires Tc/Th = 1/2. If Tc = 400 K (note that water boils at 373 K, so I am being generous), then Th = 800 K to get the required efficiency. Melting point of tungsten is 3695 K, so tungsten engine block would do (no need for ceramic).
http://www.newscientist.com/article/...in-a-spin.html

I'm sure no one wants to turn this into a forum for "Mechanical Engineering Today", but Tungsten is too brittle for an IC engine block as well (I'm pretty sure), and I'm almost positive you can't get Th to 800K even with a stochiometric mix with diesel. It's been a long time since Thermo and Energy Conversion, but If it was that wasy, we would have done it by now since Russia loosened up Tungsten sales many years ago.

...But I sure will take a look at the video post...Thanks.

[cpnscarlet]

Re: New type of Car engine

It doesn't seem to have the seals which are a problem with Wankels.

Weight seems very low, so this could be couple with a bigger battery to provide low end torque for a longer range than Priuses.

Also looks useful for constant rpm applications such as ships, generators...

Looks to me like a big plus for a variety of fuels, but I think beside some of the problems with the wankel, this type of engine will NOT burn as clean as a conventional engine unless you burn something like hydrogen, methane, or alcohol. Compression using a shock wave takes more energy than just simple delta-volume compression as well. But I'm much better at rocket engines, any automotive engineers out there care to comment???

[c1ue]

Re: New type of Car engine

50%??? Oh really? Carnot here doesn't know fact from friction.

eta max=1-(Tc/Th)...Found a ceramic engine block, have we????

Argue with wiki:

http://en.wikipedia.org/wiki/Diesel_...e_note-bmmWW-0

The MAN S80ME-C7 low speed diesel engines use 155 gram fuel per kWh for an overall energy conversion efficiency of 54.4 percent, which is the highest conversion of fuel into power by any internal or external combustion engine.^[1]

http://en.wikipedia.org/wiki/Thermal_efficiency

The largest diesel engine in the world peaks at 51.7%.

[globaleconomicollaps]

Re: New type of Car engine

http://www.msnbc.msn.com/id/42460541...ce-innovation/

Hmmmm very Wankle-ish

you know I posted about this last month:

http://www.itulip.com/forums/showthr...681#post192681

I thought it was curious nobody had anything to say about that.

-G