rotarygod

Just to throw a bit of info out there that deals with efficiency improvements. The average rotary has a bsfc in the very high .50's to low .60's which is quite high and above those of nearly all other gasoline engines. This number changes with load and rpm. There have been stratified charge rotaries that at stationary rpm's, like those in generator use, have hit bsfcs as low as .27 which is on par with the world's most efficient diesel engines. They did this without fancy cermet coatings but rather through good combustion chamber design and fuel and ignition control. That is where most of the problems are.

BTW this is why several other automakers are looking to the rotary as a generator design in series hybrids. Most people are just ignorant to what fuel economy a rotary can be made to get when you don't expect it to work over a wide rpm range. This is true with any engine but the irony is that the rotary has the advantage to the piston engine in this area.

shadycrew31

iTrader: (6)

Also you can setup a rotary to take e85/gasoline/hydrogen/any other combustible gas. Without dramatic changes, weve seen this in the Hybrid 8.

Pretty much if it burns if can get thrown into the engine. In theory you could have a series of fuel types on yrou indash screen you could select the type of fuel you wanted to burn it would load a map and away you go.

Hopefully we can see something like this in the near future.

DocBeech

iTrader: (1)

ethanol is to hard on engines, i prefer straight gas. It tears up gas tanks, fuel pumps, causes a lot of water build up. I would stay as far away from ethanol as possible.

kartweb

Precisely. The odd combustion chamber shape is the achilles heel of a rotary. The closer one can get to a spherical shape the better. (Its not just the surface area, its the distance from the ignition kernal and convective propogation).

The key is to ignite the mixture on the threshold of detonation, which also requires the lowest threshold of detonation. Its possible to design a low threshold at specific cycle time constant (RPM) but the more the shape deviates from a sphere, the narrower the band that low threshold is maintained.

The reason a rotary has such a high EGT is due to firing too late; it fires late to avoid the detonation threshold. As a result excessive heat is dumped rather then converted to mechanical energy.

I have a hunch the new 1600 configuration is focused on enhancing the combustion chamber and in its final form we may see more then 2 plugs per chamber.

kartweb

While there is some truth to that, its not as bad as you may think. In terms of corrosion its not the ethanol thats a problem its the water it may absorb. When mixed with gasoline it doesn't have as much affinity for water.

It terms of lubricity E85 is not much less effective then gasoline. Niether E85 or gasoline are nearly as effective as diesel fuel is which is why diesel engine rings last so much longer.

I run about a 30% mix of ethanol and have for about 40,000 miles now. No problems yet.

999miki

I donīt think so.

Naturally aspirated wankel engines - Renesis exceptionally, is running very agressive ignition advance, yet EGTs are higher than in piston engines, even with fact, that wankel engine has 1,5x more time for completing combustion than piston engines at same RPMs.

Moreover, Wankel engines do not need as much ignition advance, as you may think would be optimal... again, it goes down to fact that wankel cycle takes 1080° vs. 720° for piston engines. If any engine is indicating quite large gains with "more than needed" advance, there is something wrong - charging efficiency is poor or ignition cant cope with igniting denser mixture closer to the TDC.

High EGTs are simply result of poor combustion chamber combined with fact that mixture is flowing and flame front has hard time reaching the trailing side.
Even stratified charge rotaries which RG described had quite high EGTs - at load, but BSFC was, as mentioned, exceptional.