Honda Patents Engine With Different-Sized Cylinders
Balancing power and economy through clever engineeringby Jonathan Lopez, on
“The internal combustion engine is on its last legs!” We hear it all the time, usually from some source with vested interest in an all-electric alternative. And while the finite nature of petroleum is undeniable, the technology behind its utilization for transportation continues to improve, considerably extending the life of the ICE by making it more powerful and more economical – at the same time. Honda has been doing it for ages now, with previous innovations including its VTEC variable valve timing system. Now, the H-badge is at it again, this time with an engine sporting different-sized cylinders.
That’s the news coming from Autoguide, which reports Honda has filed a patent outlining the technology for it’s next-gen engine lineup, including inline two-cylinders, inline three-cylinders, inline four-cylinders, and V-6 powerplants.
Essentially, the technology uses different strokes for each cylinder. When combined with cylinder deactivation technology, it allows for a multitude of displacement combinations, therefore varying total engine displacement to best suit a given situation. For example, if Honda built a four-cylinder engine and each cylinder had a different displacement, there would be 15 different possible configurations, and therefore, 15 different options for displacement.
So far, there’s no word as to whether or not Honda will actually incorporate the tech on a production car, but here’s to hoping we’ll see it soon.
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Why it matters
Usually, engines use the same displacement for each cylinder – for example, a 3.0-liter V-6 would use six individual 0.5-liter cylinders. Equipped with cylinder deactivation technology, this hypothetical V-6 would offer different displacement totals in 0.5-liter increments, depending on how many cylinders were in use (0.5-liters for one cylinder, 1.0-liters for two cylinders, 1.5-liters for three cylinders, and so forth). While effective in its own right, this system inherently limits the number of displacement configurations possible.
Differently sized cylinders significantly increase the number of displacement possibilities, with a variety of “filler” displacements available for whatever task is required. The space between each displacement increment (0.5-liters in the previous example) would shrink, as larger and smaller displacements could combine to fill the gaps. For example, a 0.3-liter cylinder and 0.4-liter cylinder could combine to create 0.7-liters of displacement, bridging the gap between 0.5-liters and 1.0-liters.
So what does all this mean at a practical level? More power when you need, and higher efficiency when you don’t.
So far, Honda’s patent only outlines varying stroke (how far the piston moves up and down inside the cylinder), rather than bore (cylinder diameter). One of the trickier parts of implementing this tech is reducing engine vibration, a problem Honda has addressed by selectively placing higher displacement cylinders in the middle of the block.
Making it run smoothly is probably one of the biggest hurdles to putting the idea into production, as most folks won’t stand lumpy power delivery on their daily driver. That said, I wouldn’t be surprised if the pressures of increased efficiency put the tech on the development fast track. If that turns out to be the case, I’d be excited to see it in action on the street.