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Old 9th May 2016, 16:27   #1
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Default Honda patents engine with variable piston strokes (EXlink)

Honda seems to be working on a new engine design featuring a variable piston stroke.

Honda patents engine with variable piston strokes (EXlink)-hondavaryingsizedcylinderspatent01.jpg
Honda patents engine with variable piston strokes (EXlink)-hondavaryingsizedcylinderspatent02.jpg

The diagrams show what could very well end up being a next-generation engine fitted with pistons of different strokes.

Quote:
it appears that Honda is working on a solution that would vary the stroke of each cylinder in an engine, allowing each cylinder to have a different displacement. For example, if you take a current Honda 2.0-liter four-cylinder engine where each cylinder has 500cc of displacement, you can only vary the displacement in four different ways, either 500cc, 1000cc, 1500cc or 2000cc depending on how many cylinders are firing.
Yes, that essentially means an engine could have 15 different displacements working at a time, thus bringing savings in both R&D and enabling to adapt this engine in various applications.

Interestingly enough, the patent describes how the technology would work on inline- two, three and four-cylinder engines as well as a V6. this could open the new possibilities for next-gen engines that could power tomorrow’s Hondas.

http://www.autoguide.com/auto-news/2...cylinders.html
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Old 9th May 2016, 17:16   #2
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Default re: Honda patents engine with variable piston strokes (EXlink)

WOW!
Imagine transforming your car from a 0.5L petrol miser to a 2.0L guzzler and back as per your demands (acceleration / steady state) ...

I think this is more to do with ever tightening emission norms.
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Old 10th May 2016, 16:29   #3
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Default re: Honda patents engine with variable piston strokes (EXlink)

Nice to see something interesting from Honda. After the 'VTEC' of the 90s, they've really lost the R&D plot and we haven't seen anything interesting from their engineers.

Toyota mass-produced hybrids, the Germans brought direct-injection turbo-petrols + common-rail diesels + dual-clutch automatics, Tesla & Nissan are focussing big on fully electric cars, Toyota is betting on Hydrogen FCVs while Mercedes & gang already have self-driving cars ready. Honda took forever to even launch a 1.5L diesel engine which isn't exactly rocket science.

The company has lost a bit of its mojo.
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Old 10th May 2016, 16:57   #4
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Default re: Honda patents engine with variable piston strokes (EXlink)

That opens up a lot of possible power outputs from the same engine. In lay man terms - opens vast application possibilities ! Would look forward to hearing more on this development


Cheers
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Old 10th May 2016, 17:19   #5
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Default re: Honda patents engine with variable piston strokes (EXlink)

Is this the exlink?
If so, this explains it better:

http://world.honda.com/powerproducts-technology/exlink/
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Old 11th May 2016, 09:30   #6
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Default re: Honda patents engine with variable piston strokes (EXlink)

Extremely interesting concept. They can have actual implementations of sports/power/eco modes instead of just ecu maps! And adjustments for altitude for constant power delivery.
Engine balancing could be a nightmare though - it needs to be seen how that is implemented.
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Old 11th May 2016, 09:39   #7
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Default re: Honda patents engine with variable piston strokes (EXlink)

Quote:
Originally Posted by mayankk View Post
Is this the exlink?
If so, this explains it better:

http://world.honda.com/powerproducts-technology/exlink/
Thanks for the link. Much more details in there. Extremely interesting concept though I agree with GTO when he says they have lost their mojo a bit. Even Mazda seems to be doing better as far as IC engine's go with their latest line of SkyActiv engine technology.
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Old 11th May 2016, 11:58   #8
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Default re: Honda patents engine with variable piston strokes (EXlink)

Its a very interesting concept, although not new as such. There have been multiple attempts at this. But it is probably the first time for car engine.

On large (marine) diesels they have tried before, but it never amounted to much in practice. Too complicated, to many problems.

We do need to rethink a bit in how we discuss and specify engines: Cant go by displacement volume and compression ratio alone anymore.

This is the key thing behind this concept:

Quote:
In other words, the expansion ratio is larger than the compression ratio. The compression ratio is 12.2:1, enough to avoid knocking, while the expansion ratio is raised to 17.6:1.
It all looks very clever. I do wonder about the balancing of such engines. There is a whole lot more weight going around!

Jeroen
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Old 11th May 2016, 12:47   #9
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Default re: Honda patents engine with variable piston strokes (EXlink)

Quote:
Originally Posted by Jeroen View Post

It all looks very clever. I do wonder about the balancing of such engines. There is a whole lot more weight going around!

Jeroen
"Storm in a tea cup". Definitely a beautiful concept. I will buy one just because I can use the same vehicle for various rides. One design issue being the mechanical/electronic - engagement/disengagement required to alter the displacement ratio especially when this happens at a few 1000 rpm's. Otherwise this can only be a cold setting for the engine.

Last edited by anoop.nair : 11th May 2016 at 12:47. Reason: typo
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Old 11th May 2016, 13:41   #10
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Default re: Honda patents engine with variable piston strokes (EXlink)

couple of video's that give a fair idea on how the mechanics of this works





And this is how it all started:

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