the RX8’s RENESIS engine fixed the issues of the RX7’s DEI and REW Variants – the focus of that development was better fuel economy and exhaust emissions. Apex seals are also no longer an issue.

The “RENESIS2″ that Debuted with Mazda’s Taiki car moves even further in this direction but adds direct injection, further increasing fuel economy.

Bill Kurtis? ;-)

Many here have no experience with Rotaries to be speaking.

Oh wait. It’s the INTERNET…

Let’s see – Gas turbine: Continuous combustion with no vibration, the ability to run on a variety of fuel sources, no worrisome seals (and lubrication-related emissions), compact size/power ratio, efficient when run in a relatively narrow RPM/load range (which a generator would supply).

Rotary: All the problems mentioned above.

I would still work with the turbine myself.

I think you’re confusing a Wankel engine with something else regarding reliability. They are extremely reliable and they fail-safe (ie do not seize) which is why so many light aircraft use them.

Furthermore they do use oil but like a two-stroke this is by design and should be considered part of the consumables.

I think the issue was that, even with the Renesis, the rate of oil burn is bad enough that emissions are still problematic. What a hybrid powertrain allows is, I think, a fighting chance for the rotary to meet tier 2 bin 4 or higher.

But yes, you’re right in all other respects: a hybrid-electric powertrain complements a rotary perfectly. The rotary is very space efficient, but doesn’t make much torque, especially at the low end of it’s rev range; a hybrid motor-generator can help address that, while the extra space it takes is easier to work around given the rotary’s physical size.

A sub-1.0L rotary/parallel hybrid would probably fit in vehicles that couldn’t otherwise accomodate the traditional piston engine + hybrid motot/generator. The RX-8 makes ~230hp from a 1.3L two-rotor the size of a football; the ~120hp figure of the Prius could be achieved with something even smaller.

I can’t remember what is the compression on the new rotary engines? I wonder if running E100 with a relatively high compression could give good results.

“Uh… No.”

The extra complexity involved with any hybrid engine does combined with the reliablility issues of a rotary do not bode well.

I owned a RX-7, although it was a blast to drive, it had an appitite for fuel and oil. Adding a hybrid to a rotary would be simply a zero-sum equation. Whatever eco-friendliness you got from the hybrid would be counteracted by the gas, oil, and apex seal guzzling rotary.

Ethanol is the prime example of this.

The trick is to use energy more efficiently, not to play a shell game with fuels.

I’ve been intrigued lately about the use of small turbine engines as generators in EREV’s; can be very efficient, and run on a variety of fuels (even vodka in a pinch).

A lot of alternative fuels are filthy when they burn, and turbines aren’t necessarily well-suited to pairing with a catalytic converter. That will be tricky. Heck, clean exhaust is a problem for rotary engines, too.