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Harley Davidson files a patent for a new engine design


Harley Davidson is applying for a patent for a new engine design with variable valve timing. It is not the variable phase system that is officially patented, but the modular engine balancer mounted on both sides of the crankshaft. However, the patent also describes a structural element of the balancer that implements the variable timing system.

The patent uses a rough sketch of a Fat Bob as an example of a motorcycle. But the design features of the engine are described in great detail, and the essence of the differences from the current Harley engines is revealed. The design of the new engine still has overhead valves, but with rods located on opposite sides of each cylinder (this corresponds to another patent discussed earlier). Both patents were originally filed with the United States Patent and Trademark Office (USPTO) in early 2019, and both listed HD engineer Johann Voges as the sole inventor, which most likely means both patents are on the same engine. …

The images show unusual air cooling fins curved around the cylinder. Also, there is no oil filter in front of the engine. It is difficult to determine the proportions from the illustrations in the patent application, but they probably depict a replacement for an ancient Sportster series engine.


Harley Davidson files a patent for a new engine design

New engine design patent

The main thing in the patent is the balancing module of the engine (item number 74 in the drawing). The crankshaft is connected to gear # 154, which rotates the timing gear # 158. Attached to the timing gear is a slightly smaller star # 170, which rotates the chain # 178. The chain, in turn, rotates the star of the balancer, which transfers rotation to the balancing weight (no. 86) in the opposite direction to the crankshaft, compensating for the reciprocating movement of the pistons.

Variable Phase Unit # 98, connected to the timing gear, changes the camshaft timing, affecting both the intake and exhaust valves. Generally speaking, altering the intake phase will optimize power and torque distribution at low or high revs, but it is likely that Harley Davidson’s primary goal was to reduce emissions.

Harley Davidson engines, in particular the Sportster range, are currently not Euro 5 compliant, meaning they will be banned from sale by the end of the year. Several manufacturers have asked for a delay in Euro 5 due to the pandemic, which could give Harley room to maneuver in case the new engine isn’t ready yet.

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