Free Republic
Browse · Search
News/Activism
Topics · Post Article

To: Red Badger

Very cool. What is missing from the animation is the cylinder, which is still what is driving the whole thing. So whats really different is the replacement of the main shaft set up with the direct cam things. It's not a Wankle variant as I first thought.

I don't get this comment at all "The piston assembly slides rigidly through the block eliminating piston to cylinder-bore contact."

How can you eliminate piston to bore contact. Presumably the piston still has to be tight to the cylinder to facilitate controlled combustion, and preventing fuel from blowing back into the cams (which must require lubrication).

Anyone get what they are talking about?

It looks too bulky for motorycle application.

What's wrong with the Wankle? Why did only Mazda use it?


18 posted on 10/19/2005 11:37:27 AM PDT by Jack Black
[ Post Reply | Private Reply | To 10 | View Replies ]


To: Jack Black

I think what he means is that the piston is never side-loaded against the cylinder wall. Unlike a conventional engine, all the forces stay in-line with the stroke of the piston.

The problem with the Wankel engine IIRC is in maintaining a good seal between the tips of the triangular piston and the cylinder wall. It tends to get sloppy as the engine ages.


23 posted on 10/19/2005 11:44:00 AM PDT by Yardstick
[ Post Reply | Private Reply | To 18 | View Replies ]

To: Jack Black
I think they meant piston to cylinder side loading as stated further down in the article.
The problem with the wankel was the seals on the cam lobes. They wore out way too soon and were a critical part due to combustion taking place directly on the cam lobe. Wankels are still awesome even though you have to rebuild them often.
26 posted on 10/19/2005 11:47:24 AM PDT by axxmann
[ Post Reply | Private Reply | To 18 | View Replies ]

To: Jack Black

Mazda fixed the problems with it's rotary by replacing the rubber crown seals. My '82 (300,000 mis), 85, (450,000 mis) and the 92 (100,000 still running)and my soon to be RX8 never had anything but oil changes in them.


28 posted on 10/19/2005 11:49:21 AM PDT by Safetgiver (Noone spoke when the levee done broke, Blanco cried and Nagin lied.)
[ Post Reply | Private Reply | To 18 | View Replies ]

To: Jack Black
I don't get this comment at all "The piston assembly slides rigidly through the block eliminating piston to cylinder-bore contact."

I think what they meant was that the opposing pistons being ridgidly connected on one shaft are supported on the ends by the rings and the main weight of the whole assembly is supported by the bearings. The cylinder bore wear would be more "perfect circle" (pun) than normal horizontally opposed engines like BMW, VW, Porsche, Subaru, Corvair etc.........

31 posted on 10/19/2005 11:50:55 AM PDT by Red Badger (In life, you don't get what you deserve. You get what you settle for...........)
[ Post Reply | Private Reply | To 18 | View Replies ]

To: Jack Black
What's wrong with the Wankle?

There's nothing wrong with the Wankle. CAFE restrictions make it difficult to produce an economical rotary engine. They have a high power to weight ratio, but use more fuel than a reciprocating engine of the same power. The seals wear fast and rebuilds at 30,000 are not unusual. Great performance engine, but high maintenance. If you take good care of your rotary you can make them last, but most people won't do that.
.
36 posted on 10/19/2005 12:00:36 PM PDT by Joe Beerman
[ Post Reply | Private Reply | To 18 | View Replies ]

To: Jack Black
How can you eliminate piston to bore contact.

The reference is to the connecting rod forces acting upon the piston when the crankshaft rotation is at 90 degrees to the axis of the bore. The rod tends to push the piston, sideways, against the cylinder wall. It is a particular problem in short stroke engines, such as racing engines that have a high degree of "rod angularity". The longer the rod, the less the connecting rod forces act upon the piston. In this engines case, there is no connecting rod. There is also nothing new.

40 posted on 10/19/2005 12:07:37 PM PDT by elbucko
[ Post Reply | Private Reply | To 18 | View Replies ]

To: Jack Black

NSU was the first company to use the Wankel. Subsequent to Mazda's implementation, General Motors bought - but never used - rights.

The original Wankel problem was seal wear. Later, problems centered on emissions - but, this was, again, seal-related. Looking at rated reliability and service costs, I suspect that seals are still a problem. It's a very pleasing engine to drive, but, so far, just not practical; a Mazda salesman recently cautioned me that the latest model should be allowed a few minutes to warm up - get real!


43 posted on 10/19/2005 12:11:16 PM PDT by mdefranc
[ Post Reply | Private Reply | To 18 | View Replies ]

To: Jack Black

"What's wrong with the Wankle? Why did only Mazda use it?"

The dying gasp of Norton motorcycles was a wankel powered bike.


46 posted on 10/19/2005 12:18:38 PM PDT by CATravelAgent (Suppose you were an idiot, and suppose you were a member of Congress. But I repeat myself.)
[ Post Reply | Private Reply | To 18 | View Replies ]

To: Jack Black

mazda bought the rights. that’s why it was never developed any better.
Ofcause the ring on the piston is very close to touching the bore to use the combustion, they mean a standard IC engine tries to push the piston sideways as it travels up the bore where the revetec cce does not try to do that so much


107 posted on 05/08/2007 6:19:08 AM PDT by notnilC ((NO ONE))
[ Post Reply | Private Reply | To 18 | View Replies ]

Free Republic
Browse · Search
News/Activism
Topics · Post Article


FreeRepublic, LLC, PO BOX 9771, FRESNO, CA 93794
FreeRepublic.com is powered by software copyright 2000-2008 John Robinson