Fresh from the office of the USPTO, we have confirmation that Honda has just received the patent for the first ever three-stroke motorcycle engine.
As you would expect, the unconventional engine design incorporates the power-to-displacement efficiencies of a two-stroke smoker, with fuel-to-power efficiencies of a four-stroke motor.
For many in the space, the three-stroke engine has been the Holy Grail of engine designs, with many OEMs rumored to have been working on a three-stroke engine.
Still, it is surprising to see the engineers at Honda claim the prize, as the Japanese brand up until recently has been heavily committed to its four-stroke technology.
Obviously, the engine technology can obviously be applied to any internal combustion application, however what makes this news especially A&R worthy is that Honda’s patent specifically states the engine’s purpose in two-wheeled vehicles, watercraft, lawnmowers, and generators.
For those who don’t know, on a conventional four-stroke engine, the engine goes through a four distinct cycles that lead to combustion of fuel, often characterized with the short-hand of “suck, squeeze, bang, and blow” by gear heads.
However, on the three-stroke engine design, the second cycle from the four-stroke cycle is omitted completely from use.
Honda states in its patent that their research shows that the second cycle was unnecessary in order to achieve optimal performance, especially when the engine’s design expedited the initiation of the third or “bang” cycle of the motor.
In fact, much of the three-stroke patent involves a detailed explanation of Honda’s “Bang Initiator” technology, which presumably could trickle down into four-stroke machines as well (it should be noted that HRC has also trademarked the name “Honda Big Bang” for use on motor vehicles).
Like on a two-stroke design, the engine is lubricated through a fuel pre-mix. This is achieved in the final cycle of the three-stroke engine’s combustion, and is accomplished by what Honda calls a “constant lubrication” pump that works with each stroke of the piston. We should note that this process is referenced in a different patent.
While we expect to see the new “suck, bang, blow” three-stroke engine to takeover the powersports market, we likely won’t see the first models with this capability until the 2018/2019 model years, at the earliest.
While we look forward to this ground-breaking engine technology, but we also hope that Honda has considered the marketing aspect of the three-stroke engine, as there are devout fans of the old four-stroke way of doing things.
They, along with older riders who are used to the old two-stroke days, will need to be won over by this new combustion method.