Harley-Davidson files patent for supercharged V-twin

H-D looking into supercharger for more power

Milwaukee-based Harley-Davidson could soon be joining the other manufacturers on the supercharged and turbocharged bandwagon.

In a recent patent filing by the Bar and Shield, a supercharger device might soon be powering future Harley-Davidson baggers to meet tightening emissions controls while squeezing more power out of their V-twins.

According to the patent designs, the supercharger will be placed close to the throttle body, on a self-adjusting latch, which is in the middle of the 90˚ V-twin motor. Based on the drawings, the supercharger will be powered by the engine’s crankshaft via what seems to be a belt drive.

Forced induction in motorcycles

Most motorcycle riders may think using superchargers in motorcycles is a Kawasaki innovation, thanks H2 and Z H2. But superchargers or other forced-induction technologies, are actually not a new technology.

During the '80s, the "Big 4" Japanese motorcycle manufacturers each experimented with the technology and produced models like the Suzuki XN85, Honda CX650 Turbo, Kawasaki GPZ750 Turbo, and Yamaha XJ650 Turbo.

Forced-induction, in layman’s terms, compresses the air from the intake and forces it into the combustion chamber. This denser air therefore producers a more powerful combustion force, burning the fuel more completely during the combustion. It creates more power versus a naturally-aspirated engine with the same displacement.

Why now?

Tightening restrictions on carbon emissions are motivating brands like H-D to mass-produce motorcycles with forced induction devices, like a supercharger. This lets them produce more power with each new model while still meeting emissions restrictions. Honda is already considering doing this, with many other brands like BMW and Yamaha also playing with the idea.

They're taking a cue from car manufacturers who have already been playing with this kind of technology long before the Kawasaki H2.

In some diesel cars, for example, rather than putting a bigger engine, adding a turbo to a small engine can produce similar power, burn most of the fuel during the combustion process, and also return cleaner emissions. That might be the same idea behind why motorcycle manufacturers are now exploring the application of forced induction on their motorcycle models.