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Honda Patents Engine With Multiple Stroke Lengths

From Road & Track

Honda's always had a knack for developing innovative engines, but even by its standards, this is pretty strange. Earlier this year, Honda was granted a patent in Japan for an engine that has different displacements for each cylinder. The patent describes two-, three-, four-, and six-cylinder engines with identical cylinder bore diameters, but different stroke lengths for each.

The patent, which was first uncovered by Autoguide, doesn't explain why an engine with multiple cylinder displacements is advantageous, but we imagine it's an attempt to improve fuel economy without compromising performance. Perhaps it could work in conjunction with today's cylinder deactivation technology, activating the larger cylinders when more power is needed and shutting them off at lighter loads. It's unclear whether the crank throw in this design is adjustable, or whether it uses multiple stroke lengths of fixed sizes on a single crankshaft.

It's important to note that a granted patent doesn't necessarily mean this tech will be put into production: Automakers file thousands of patents a year to protect their intellectual property. Multiple cylinder displacements are a very left-field idea-but remember, Honda is the company that gave us oval-shaped pistons. This kind of unconventional thinking is, strangely enough, rather conventional for Honda.