So I was reading up on the rotary and did a search and couldnt find it.
But do current apex seals use cross-hollow seals? They were used along time ago apparently and sustained and allowed the rotary to sustain 300 hours of continuos high speed testing. This idea was scrapped by mazda in the production line but used in more testing. So do the manufacturers of seals use this technique? If anyone has a link that would be great too.

 

BTW im just doing some research not acting like I know more than anyone on whats going on or anything but it does make me curious if they dont make the seal why no one would make it now! Thanks.

 

Mate, im doing a project on wankel engines. What ive learnt is that most of the people here talk from experience and have practical knowledge and no thepretical knowledge or facts.
No kne digs deep.
Run premix and ceramic seals is what everyone is on about.

 

i think the cross hollow seal was more expensive to produce, than the carbon seal which followed it. i've got a bunch of carbon seal engines, but i've never even seen a cross hollow seal engine

 

never heard of such a thing. if you want a light material for high revs the only 2 options are carbon and ceramic.

 

MAZDA:Engineering History | The Rotary Engine

actually i guess the cross hollow design didn't even make it into a production car at all.

 

I have never heard about anyone using cross hollow apex seals besides Mazda in their early testing to damp vibration and eliminate the chatter marks present in the engines they received from NSU when they bought into the Wankel Consortium.

All the consortium members were fighting against the chatter marks and some other interesting ideas were tried.

Sachs made a more complex gear driven eccentric shaft lobe to dampen rotor vibrations and directional changes (rotor tilt) and ultimately found controlling chatter also stemmed from controlling rotor housing surface temperatures and ran the primary intake ports through the hot side of the engine in their air cooled industrial motor.

If you haven't already, find the definitive book- the wankel engine design development applications Jan P. Norbye 1971

 

7 year old thread and i'm only now just hearing about these seals? they definitely have me curious now though ....

 

Decisions based on cost...like the switch from 3 piece seals to 2 piece? Sounds legit.

 

Decisions based on cost...like the switch from 3 piece seals to 2 piece? Sounds legit.

Do we know the switch from 3 piece to 2 piece seal was for cost? It seems a lot cheaper to keep making what you have been making than re-design a product.

Maybe they switched to 2 piece since they no longer produced the car and so no longer had to meet manufacturers emissions standards and thus switched to a stronger design.

Purely speculation on my part.

 

switched to a cheaper design

 

My understanding is that the cross hollow seals were an attempt to damp the seal vibration that caused chatter marks. Once Mazda realized the chatter was due to a resonant vibration, they were able to design plain steel seals that ran smoothly and did not need the complex geometry.

I see no reason they are applicable now, modern ceramic apex seals are stronger and lighter than any steel ones, and the 'nail marks of the devil' have long since been eliminated.

 

Actually, Mazda switched to Carbon compound apex seals for production and then after they had to replace a whole bunch of engines under warranty they went to steel seals.

 

^Iron seals, you meant to say.

 

I have never heard of anyone using Iron seals. Did they try this?

 

^ Mazda describes the stock seals as iron. Many piston rings are made of specialty iron materials as well. This normally just means that they have too high carbon content to be a pure steel alloy, which is desirable for seals because it increases lubricity.

 

they are made by Nippon piston ring, so if you think of the apex and side seals as piston rings, you're really not too far off...