Axial engine - good for PHEV?

[LTLFTcomposite]

This looked interesting, I wonder if it could be applied to a PHEV? Smaller. lighter engine package, more batteries.

https://rideapart.com/articles/duke-axial-motorcycle-engine" onclick="window.open(this.href);return false;

 

[Deleted member 14724]

This looked interesting, I wonder if it could be applied to a PHEV? Smaller. lighter engine package, more batteries.

https://rideapart.com/articles/duke-axial-motorcycle-engine" onclick="window.open(this.href);return false;

Interesting. But looking at the size of the range extender engine in the BMW i3, for example, makes me think that a car manufacturer probably would not risk an unproven technology for anything less than a massive potential benefit. And I don't think the benefits would be massive over a more conventional 2 or 3 cylinder engine, even if it turned out to be very reliable.

 

[Petecomp1]

OP, thanks for the link, I dug the video! I seem to remember seeing a similar design used for powering torpedoes, that was called a "swashplate" engine I think. I was once enamored of the Wankel but that affair was crushed after the reliability and fuel economy problems became clear. It appears Duke will make durned sure they don't suffer a similar fate. If so, this would be a dandy range extender. Say 600cc, about the size of a gallon paint can, at 70 HP? Imagine my Leaf with 350 mile range... Cool!

 

[JeremyW]

This looks like it has a lot of the same disadvantages as a wankel. You have areas that are constantly hot and others that are constantly cold and you have to have a moving seal against both surfaces. How does the cylinder block seal against the head?

 

[minispeed]

I think we're more likely to see a turbine or a wankel before that.

A lot of the disadvantages of a wankel are offset by PHEV duty. It's not going to wear that much if it's not used as much. ex. volt stats that say most driving is done on electricity. They also aren't that bad, after all RX7s 20-35 years old are still going, RX8s while not the model high mileage car aren't exactly falling apart either. If the unit gets light and cheap enough they can be modular and slide in and out relatively easily. Since it will be used as a generator it doesn't have to operate on a wide rpm band and can be tunned for optimum efficiency and it's size/weight savings of not just the engine itself but also sound deadening, mounts, subframe etc... may make up for it's inherent efficiency loss. It will also allow for higher rpm generator use with less NVH. The current volt had a review I read a long time ago that said it could have achieved much better ICE MPG at a higher RPM but was deemed to be too harsh and the next volt is going with a larger ICE with the stated reason that it will allow it to run smoother and quieter.

 

[Petecomp1]

This looks like it has a lot of the same disadvantages as a wankel. You have areas that are constantly hot and others that are constantly cold and you have to have a moving seal against both surfaces. How does the cylinder block seal against the head?

I was thinking the same thing. It's the sliding seal along with heat control that's the issue. Of course, regular piston rings are a sliding seal and they seem to last a long time, so maybe Duke will succeed. Another related issue is sealing of the port openings especially on compression & combustion. Too much leakage here will nullify all the efficiency of the engine. Still, there are advances in metallurgy all the time these days, so they might make it work. I think the smaller package size per HP makes it worth the effort.

 

[JeremyW]

Indeed, it is in the range extender application where unconventional engines may work well. Things like slow change in power output, startup and shutdown requirements, and idle efficiency are not difficult to deal with in such an application. High efficiency, high specific power, and small size are the most important requirements.

Of course, if battery cost falls fast enough, most will never see the light of day.