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Electric Trials Bike R&D

One Approach toward Carbon Neutrality

Achieving carbon neutrality is an issue pertinent to the entire world. In its goal to achieve carbon neutrality throughout all of its business activities—including across the life cycles of its products—by 2050, Yamaha Motor sees electrification as one important key to reducing its CO2 emissions, and to that end is engaged in a range of R&D pursuits for advanced technologies.

Examining the Potential of EVs to Surpass Conventional Engines

There is a system in place within Yamaha Motor's R&D departments that allows employees to use 5% of their working hours for voluntary, independent research and is dubbed “Evolving R&D” (also known as the “5% Rule”). The TY-E electric trials bike is an advanced development vehicle created in 2018 through this 5% Rule.

But why develop a trials bike? It all began with the biggest hurdle that electric vehicles face both in their development and propagation: range. Trials competition inherently does not require a machine capable of long distances and the powertrain traits desired in a bike for it are low-down and midrange torque and manageable power delivery that responds faithfully to a rider's subtle inputs. From that perspective, electric motors are actually better suited to trials than conventional internal combustion engines (ICEs).

Trials is a points-based competition in which motorcycle riders must traverse a pre-determined course made up of sections using the natural terrain, such as steep rockfaces, inclines, rocky outcroppings, and trees. If a rider can navigate a section without putting their foot on the ground, they are awarded full points and alternatively have points deducted if they do touch the ground. Finishing positions are decided by the total number of points across several sections.

On the other hand, a trials bike must have a highly rigid chassis, but still be extremely lightweight. On this point, building an electric trials bike presents a different hurdle to overcome and one that has been marring all kinds of EVs for some time: reducing the weight of the battery system.

The fact that all-electric cars grew more commonplace first in luxury and supercar segments points to the reality that the price tag is still a barrier when developing EV technologies to meet requirements suitable for the wider market. Yamaha Motor has long been involved in the R&D of electric motorcycles, but factoring costs into the product makes balancing the three-way trade-off between range, power/torque characteristics, and weight an even more difficult puzzle to solve. But deploying a minimal number of dedicated competition vehicles in a factory team offers different conditions to meet from a production vehicle, providing comparatively more freedom for R&D.

Based on this background, Yamaha Motor turned its eyes to the transition to electrification the motorcycle world has made greater calls for, i.e., advanced technologies that will lead to wider use. Instead of seeking to simply emulate gasoline engines, the goal was to surpass them with an EV boasting both higher output and efficiency. As part of R&D for exploring that possibility, the TY-E electric trials bike was unveiled in 2018.

Aimed at Providing More Fun than a Conventional Gasoline Engine

In 2021, Yamaha Motor reviewed its Yamaha Motor Group Environmental Plan 2050 first formulated in 2018 and set a new goal to achieve carbon neutrality throughout all of its business activities—including across the life cycles of its products—by 2050. The R&D project to explore the untapped potential of EVs through electric trials bikes also entered its next phase, with the TY-E evolving into the TY-E 2.0 in 2022 with an approach emphasizing the potential for fun while moving toward a carbon-neutral world.

The TY-E electric trials bike
(photo shows 2.0 version from 2022)

The TY-E 2.0's development concept was FUN×EV, looking to provide fun that surpasses ICEs by taking advantage of the unique traits of electric vehicles, such as powerful low-down torque and acceleration.

Its newly designed composite monocoque frame houses a higher-performing electric power unit that uses a combination of mechanical parts and electronic control, and the newly developed lightweight battery boasts some 2.5 times the usable capacity of the previous model. The TY-E 2.0 itself has seen further progress with its R&D and, like its predecessor, is set to be tested and refined through real-world competition. In 2023, the updated TY-E 2.1 will compete full-time in the All Japan Trial Championship, making it the first electric bike in the series' history to do so.

As reducing greenhouse gases grows increasingly critical for the world, the motorcycle industry is also on the cusp of its own transitional period to electrics, and acquiring various fundamental technologies, expertise, and know-how for creating EVs remain the chief goals of Yamaha Motor's electric trials bike R&D.

However, that's not all. Even if powertrains and their peripheral technologies change, the fun people feel through mobility is something that must remain, and answering the expectations of people who believe that that fun factor should continue to exist even in a carbon-neutral world is yet one more goal of Yamaha Motor's TY-E R&D project.

TY-E Technologies

Removable Battery Featuring High Energy Density

To tailor the battery for use in a trials motorcycle, where lightweight and compactness are paramount, the chief focus for its technological development was to achieve an output density higher than conventional removable batteries, and its standout feature is the volumetric density which is noticeably higher than the average removable battery.

With the first-generation TY-E in 2018, increasing output density was prioritized and the design sacrificed energy density to achieve that task. But the newly developed battery for the TY-E 2.0 retains the same high output density while also achieving an energy density of a considerably high level for a typical removable battery.

The TY-E 2.0's removable battery

Battery advances from the first-generation TY-E in 2018 to the TY-E 2.0

A Powertrain Combining Electric and Mechanical Components

The high-density coils in the TY-E's motor are how it achieves not only high rpm and high output numbers but also a lightweight and compact shape. Additionally, another feature of the TY-E's powertrain is its mechanical clutch and flywheel—two items unneeded by typical EVs—that complement the motor’s high output, a trait required in trials competition.

The mechanical clutch has a lightweight construction that also works well to transmit the high output density of the motor, and was adopted to raise efficiency when converting the motor's rotational energy into drive force.

The energy stored by the flywheel is far smaller than the energy supplied from the battery and is also instantly consumed, but the team actually turned their eyes to that very instant, believing that it held the key to extracting a high degree of drive force not present in a typical battery/motor combination. To provide the lightness and instant power on tap needed in a trials bike, the TY-E employs this flywheel/battery combination.

Note: The energy conversion process with a conventional EV takes the energy stored in the battery, directs it through an inverter and motor to convert it into rotational energy, and then uses that to drive the wheels, but the output density needed for an electric trials bike could not be achieved with this usual process.

Model-specific motor specialized for high output density
(photo shows TY-E 2.0)
Powertrain setup and energy conversion process
(photo shows TY-E 2.0)

Carbon Fiber Reinforced Plastic (CFRP) Monocoque Frame

Adopting a monocoque design and carbon fiber composites for the frame represents a significant departure from trials motorcycles with internal combustion engines. This design results in a chassis weight and frame rigidity balance optimized for an electric motorcycle—one that also reduces overall weight. The TY-E 2.0 carries on and evolves the same basic frame concept of the original: to heighten longitudinal and torsional rigidity while keeping lateral rigidity low.

The monocoque frame is designed with the space to accommodate the removable battery while also ensuring sufficient strength and striking the right balance for rigidity and weight across the entire chassis.

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