Newly revealed Yamaha patents show the Japanese company working on two different hybrid drive solutions, based on the T-Max platform.

Yamaha Patents Hybrid Drive Ideas

In the face of increasing pressure to abandon internal combustion engines (ICE) completely, a number of manufacturers are continuing work on hybrid drive systems, combining an electric motor with an ICE, either in series or parallel.

In a series hybrid, the wheels are driven by the electric motors alone, the ICE is there to merely charge the batteries. In a parallel hybrid, both ICE and electric motor are connected to the wheels and the both can drive the wheels individually or together.

Yamaha has gone the parallel route but it has patented two different methods of power transmission to the rear wheel. One has the electric motor connected directly to the engine's crankshaft and the other connected to the transmission. Both have pros and cons.

The first patent application shows the electric motor being directly linked to the ICE via the crankshaft. This method simplifies connection between the two and has the advantage that there is only one source of the engine's power output. It also means that not only can a conventional transmission be used but the entire power unit could be fitted to any number of motorcycle styles.

The second idea leaves the ICE as a completely separate entity and couples the electric motor with the transmission. While this leaves the engine selection completely free, it does mean the whole transmission - drive from engine, integrating gearbox and electric motor and drive to the back wheel - is necessarily much more complex but, once perfected, would create a modular system that could be fitted to any number of engines. This method also has the disadvantage of separating the two power sources and integrating them seamlessly through the transmission isn't easy.

What the patents don't tell us is when we might see the technology being fitted to a motorcycle. Just becasue the illustrations show a T-Max-type maxi-scooter, doesn't mean it will automatically be seen in such a model, although the layout of a maxi-scooter does lend itself to accommodating all the batteries, electric motor and associated electronics, even if that would eat into the under-seat storage which is a feature of these bikes and a big selling point for many.