Have anyone think or tried this?

I saw a thread : but this is not real compound turbo

 

Detroit diesel is the most recent stuff I've seen to use it. I've never seen it on a rotary but I imagine our engine packaging makes it pretty difficult. Generally you want the exhaust to go through the turbo first which would mean you have very little room to pull exhaust from the down pipe to feed the rear of the e-shaft. Not to mention its a pretty custom deal to get a gear onto the e-shaft and the difference between the exhaust turbine speed vs e-shaft is going to be interesting. You could try going off the flywheel to test your stuff and see how it goes before you go all out.

 

The primary difference between Paul Lamar's purpose of application and putting it in a mazda is what is being driven. What is being proposed is the turbine, spun by exhaust gas, then drives the e-shaft which is directly connected to a propeller that exhibits a polar moment of inertia of SFA and only has air to create a force against it, again, sfa. The salient point is that the turbine does not spin freely but is dictated by the speed of the shaft.

In a car application the e-shaft, via a gearbox, spins two tyres which are attached to the car. The car does not have a moment of inertia of sfa. It has an I of really very #### big. The only time this is reduced is when the engine produces enough torque to break traction. The issue here is that by limiting the speed of the turbine wheel, you create exhaust back pressure. To avoid this back pressure, you could increase the size of the housing significantly so that the wheel doesn't act as a blockage, but that defeats the purpose of the turbine doesn't it.

The reason why it works in aircraft and not in cars is because the rotational speed of the propeller is independent of the aircraft's velocity, where the rotational speed of the tyres and car velocity have a strong correlation.

Car manufacturers aren't that far removed from aviation technology not to have tried it if they thought it would work. After all, several have roots from aircraft industry.

 

alternatively, the turbine could power a generator similar to a kers system but based on exhaust. This is standard application in locomotives.

 

Or a fluid coupling (torque converter). Still, the chances you could get a turbine assembly which did anything of use in to the footprint of say a 20b (13b+1 rotor worth of space for the turbine) without the resources of a major corporation is probably pretty slim.

 

The concept would work well in an automotive application on a small rotary engine coupled to a generator which drove electric drive motors.

I think the complexity would make it too expensive for production though.

 

It works very very well on planes. It effectively started the path that lead to turbine engines.