Yamaha Back in the Hybrid Game

[Hugh Janus]

Back to the future? New patents show Yamaha is exploring hybrid motorcycle designs once again. (Japanese Patent Office/)

Most people seem to forget, but Yamaha embraced hybrid motorcycles early on. Do a quick rewind to the early part of the 21st century and you’ll see the company was one of the strongest proponents of the idea of hybrids at the time; in fact, if it wasn’t for the 2008 financial crash, it might well have been selling them for a decade by now.

RELATED: Where Are The Hybrid Motorcycles?

But Yamaha’s hybrid project ground to a halt around 2009-2010 as bike firms worldwide slashed R&D expenditure, and there’s been no sign of a revival for the idea until now. A new patent application in Japan has revealed that the firm is once again ramping up its hybrid efforts.

Yamaha’s latest idea is for a series hybrid rather than a parallel design. The single-cylinder engine is attached to a generator, which powers the battery. (Japanese Patent Office/)

To get an idea of how strongly Yamaha believed in hybrid bikes, we need to go back to the 2005 Tokyo Motor Show, where the firm revealed its Gen-Ryu cruiser concept. It was powered by the 600cc four-cylinder engine from the R6 sportbike, driving through a planetary gear transmission like that of a then-current Toyota Prius, thus allowing a large electric motor/generator unit to either take up drive on its own, assist the combustion engine, or to regenerate electricity.

The high-concept four-cylinder Gen-Ryu concept of 2005 revealed the high level of Yamaha’s interest in hybrids. (Yamaha Motor Corp./)

Although clearly a pretty wild concept, the Gen-Ryu’s technology was based on a real R&D project at the time, which emerged four years later—again at the Tokyo Motor Show—as the much more down-to-earth HV-X. However, unlike most show concepts, the HV-X wasn’t trumpeted by Yamaha, and indeed it has only been revealed by the firm as a cutaway model at the Tokyo event and in a video showing the bike in action. However, design patents at the time revealed a surprisingly production-ready machine. It appears that Yamaha’s low-key unveiling, which came just as the motorcycle industry retracted in the face of the financial crisis, was due to the project being shelved at around the same time.

The Gen-Ryu begat the HV-X concept bike in 2009, which used a CVT transmission to tap both gas and electric power. (Yamaha Motor Corp./)

Like the Gen-Ryu, the HV-X used a Prius-style planetary gearset to create a CVT transmission that could seamlessly mix gas and electric power. This time the engine was a 250cc single allied to a 15kW (20 hp) electric motor and bolted into the frame from an XP500 TMAX. A 300V battery sat between the rider’s legs, with a gas tank under the seat.

The HV-X design called for a 250cc single paired with a 15kW electric motor bolted onto the frame of a TMAX scooter. (Yamaha /)

Since 2009 there’s been no sign of Yamaha’s hybrid project until the publication of a new patent application in Japan showing the idea is once again in development, albeit in a very different form.

Yamaha’s new design patent relates mainly to the chassis layout, which uses the single-speed gearbox as a structural element. (Japanese Patent Office/)

The Gen-Ryu and HV-X projects of the time were so-called “parallel” hybrid designs, where both the combustion engine and electric motor were able to drive the rear wheel, but the new design is of a series hybrid. That means the ICE (internal combustion engine) can’t drive the vehicle, instead powering a generator that charges the battery. The single-cylinder engine sits where you’d expect on a scooter-style vehicle, but it’s attached to a generator that’s bolted alongside it (numbered “42” in the patent images). Behind it an electric motor (51) is mounted on a single-speed reduction gearbox that drives the bike’s front sprocket. A fairly large battery (60) sits under the seat. The patent itself relates to the layout of the chassis, which uses the reduction gearbox as a structural part, with a frame ahead of it to support the steering head. It’s basically the same chassis idea the TMAX scooter uses and that the HV-X intended to borrow, just reworked to suit a series hybrid design.

Using the chassis design of an existing model but with a different power source could be Yamaha’s way into the electric market. ( Japanese Patent Office/)

With electric bikes still remaining niche vehicles, in part because of the range anxiety that comes with the knowledge that you can’t simply top up a fuel tank when the power runs out, hybrid bikes like this could still have a viable future. Combustion engines might be more complex than electric motors, but they’re cheap thanks to a century of mass production, and a series hybrid could get away with a smaller battery or use cheaper, less energy-dense battery technology to reduce weight or cost compared to a fully electric bike of similar performance and range. Hybrids might not be as cutting-edge as they were when Yamaha first started working on the idea around 20 years ago, but it might yet get them into mainstream use one day.

Source