AMCN recently revealed that a Yamaha electric motocross bike is in development using lessons learnt from the company’s TY-E electric trials machine, and now the company has filed several more patents showing the bike and revealing details of its construction and technology.
The original patent demonstrated one of the biggest changes from the trials bike to a motocross machine with the elimination of the TY-E’s clutch and flywheel. These are used on the trials bike to add the fine controllability and balance needed for the sport, adding a conventional clutch and flywheel to allow the motor to be revved without turning the rear wheel. The rotating mass of the flywheel acts as a gyroscope to help balance the bike, and as an energy store to allow instant bursts of immediate torque when the clutch is engaged.
On the motocross bike, those relatively heavy parts will be replaced with a pair of drive plates connected by springs instead of a clutch. This gives direct drive, like most electric motorcycles, but with the springs providing a damping effect to help control the torque of the motor. They also act as energy stores so when you slam the throttle open, they first compress and then extend to release that stored energy for an extra thump of torque. Alternatively, the bike could be held on the brakes and power added to compress the drive plate springs before a launch, allowing more instant torque when the brake is released than would be available from the motor alone.
The new patents add more detail to the motocross bike’s development, including a power rationing system, which will let riders input the expected length or time duration of a race before the start. Armed with that information, the bike will measure out the battery’s energy to ensure that it has enough to finish, allowing the rider to go flat out for the whole race without having to worry about energy consumption.
WORDS: BEN PURVIS
