New engines?

[eesquared]

Eric, you might already know about this shock wave disc engine. My son sent me this article:

http://www.popsci.com/cars/article/2...ustion-engines

I can't say I'm wild about the $2.5 mil grant that they are receiving to study and develop the engine, but I think it's pretty cool if they can get an engine to work without a transmission or a cooling system.

I guess my question is: Theoretically, could it work to replace all our driving habits, including long distance driving? I also wonder what kind of car they would need to design to use it since it is much smaller and much lighter.

Thoughts anyone?

[Dave Brand]

All the reports on this thing say that they have "developed a prototype"; not so - all they have done is made a transparent model to illustrate a theoretical concept.

I'll believe it when I actually see one running, something which, I suspect, is easier said than done. I can see big problems in such areas as sealing & lubrication which may well seriously affect actual, versus theoretical, efficiency.

[dom]

Reminds me of a rotary unit.

Here is the diagram from the article.

[Ken]

Reminds me of a rotary unit.

Here is the diagram from the article.

Looks like a sort of two stroke compression ignition turbine.

Ken.

[grouch]

Eric, you might already know about this shock wave disc engine. My son sent me this article:

http://www.popsci.com/cars/article/2...ustion-engines

I can't say I'm wild about the $2.5 mil grant that they are receiving to study and develop the engine, but I think it's pretty cool if they can get an engine to work without a transmission or a cooling system.

I guess my question is: Theoretically, could it work to replace all our driving habits, including long distance driving? I also wonder what kind of car they would need to design to use it since it is much smaller and much lighter.

Thoughts anyone?

A Sterling engine would drive a car but it would cost a LOT more to run. The engine you saw is a grant source mostly. It's what keeps researchers working until they can get honest work.

[eesquared]

It's what keeps researchers working until they can get honest work.

Yeah, I kinda figured that.

How would it be more costly to run?

[MikeHalloran]

It's not clear that it _would_ run.

Even if it would run, it may be difficult to start.

It took Mazda roughly 20 years of development to get their Wankel rotor tip seals to work and to last. The subject engine would have similar sealing problems, but would require many more seals.
They're not cheap.

There is no mechanical displacement change in the engine; all of the compression comes from the shock waves. I'm guessing that it may be necessary to spool it up to maximum speed, or damn near, just to get it started. Even accepting that, I'd expect its compression 'ratio' to fall with decreasing speed, which by itself would reduce the engine's efficiency and make emission controls more complicated if not more difficult, and I'm also conjecturing that there will be some substantial speed under which the engine will stop working, so driveability may be a huge issue.

Which is to say, even if it runs, I don't think it will idle, so it will be sucking in fuel, and lots of it, all the time.

[grouch]

It's what keeps researchers working until they can get honest work.

Yeah, I kinda figured that.

How would it be more costly to run?

It would probably be like the turbine engines Chrysler built in the early 60's. They built 50 prototypes and the cars ran quite well. Anything that would burn and could be poured into the fuel tank did just fine. All but a handful were destroyed due to tax considerations. They slurped fuel like it was going out of style. Exhaust temperatures were about 20,000 degrees. There was a lot of engineering needed to make it a feasable engine and when the tax credit ran out, they went crunch. There are a few still running. I saw one a few years ago in St. Louis at the transportation museum there. As the car was idling, the pavement behind it was getting soft.