Prechamber Combustion for Future Honda Superbikes? 1

[dgallup]

Prechamber Combustion for Future Honda Superbikes?

Interesting adoption of F1 tech to high performance street bikes. I can see some real benefits to that rotating shaft between the pre-chamber and the combustion chamber but also some potential problems with carbon build up, oil seal leakage, etc.

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

 

[TugboatEng]

Carbon buildup was never a big problem for pre-chamber diesel engines though gas seems to leave some harder deposits due to alkanes?

No oil seals necessary. This is all driven within the engine. A small amount of lube bypassing is no big deal, better than lube lost through valve guides as this one has a chance to burn.

Exhaust blowby into the crankcase will be managed by the PCV system the same as blow-by through valve guides.

 

[BrianPetersen]

Sealing will most certainly be necessary. They have a rotating shaft the length of the engine passing between all four cylinders and into the crank space where the drive mechanism is. There has to be sealing between adjacent cylinders to avoid combustion pressure leaking between cylinders. And that shaft is going to have to be made of something special to withstand the operating conditions.

The F1 version (that we the public know of) uses a fixed prechamber but no direct fuel injection into it, it's completely passive (rules prohibit more than one injector per cylinder). There's another version (not for F1) that uses a direct injector and an external injector with a fixed prechamber. But it wasn't developed by Honda, so I suppose someone wants to bypass patent royalties ...

https://www.mahle-powertrain.com/en/experience/mahle-jet-ignition/

 

[TugboatEng]

A little bit of exhaust communication between cylinders shouldn't cause much trouble. Simple labyrinth seals should be sufficient here.

 

[BrianPetersen]

At combustion pressure? That would act like a blown head gasket between cylinders.

I suppose if the space for the shaft is a single diameter the whole length, and arranged for a tight clearance fit the whole length, the leakage path would be the clearance between the two and the cylinder bore spacing less the prechamber diameter, adding to the resistance to flow. I just don't see this happening relative to the Mahle setup that has no extra moving parts.

 

[CWB1]

Yup, definitely interesting but something I would expect more from the Italian spaghetti-bike crowd than Honda. Count me also among those curious to see the durability if it hits production.

 

[TugboatEng]

Insurance rates have relegatesld the 1000cc superbike replica class to the the wealthy, they simply aren't selling any more. This gives Honda a chance to build a bike that probably won't be used as a commuter. See also the NSR750 with its oval pistons though this will likely be much less expensive to produce.

 

[RodRico]

Shades of Compound Vortex Controlled Combustion (CVCC) which allowed Honda's cars to meet US emission standards in the 1970s without a catalytic converter.

 

[BrianPetersen]

I had a 1978 Civic with that system once upon a time. Worked fine when the car was new, but eventually, carbon buildup and who knows what other problems led to atrocious driveability issues. At the end, only I could drive it, because you had to know just how much accelerator pedal to give it to get it to start, and when accelerating, you had to know just how much accelerator pedal to give it to keep it running without massive and spectacular backfires out the exhaust. Rest of the car was worthless at that point, so I never did troubleshoot this.