Biperformance Development Corporation Introduces the ShiftFX Electronic Shift Transmission for OEM Applications
The BDC demonstrator model with ShiftFX Electronic Shift Transmission in action
Following several years of research and development, including the use of materials and technology new to the motorcycle industry, Biperformance Development Corporation (BDC) announces the completion of its state-of-the-art transmission control system for OEM motorcycle applications, the ShiftFX Electronic Shift Transmission (EST). The system builds on existing gearbox design, adding a sleek, simple rider interface to provide push-button semi-automatic or fully automatic shifting.
In automatic mode, ShiftFX EST provides a much simpler interface that eases a new rider's introduction into motorcycling by eliminating the need to operate the clutch or manually shift the transmission. The automatic mode also offers convenience for all riders by reducing fatigue in heavy traffic, over long distances, or in adventure-type riding.
In semi-automatic mode, the transmission is shifted by electronic controls and the rider need only push a button to initiate an upshift or downshift, in a manner similar to high-end sports cars that are operated using a paddle shifter. Gear changes are precisely sequenced with engine control and occur in less than 50 ms, with the power cut on upshifts limited to as little as 30 ms.
The highlights of the ShiftFX EST are:
- Automatic mode ideal for new riders, with simple rider interface and no stalling.
- Semi-automatic mode offers smooth, precise push-button shifting with average shift time of 50 milliseconds.
- Retains manual clutch lever for emergency braking, aggressive launches or poor traction situations.
- Reduces engine, clutch and transmission wear and abuse.
- Communicates with ECU via CAN bus for rpm matching, engine braking and incorporation into OEM riding modes.
- Programmable for any desired load/speed characteristics.
- Applicable to almost any motorcycle, including electric bikes.
The components of the Electronic Shift Transmission and their placement on the motorcycle: The Transmission Control Unit (TCU), automatic clutch, rider interface, Active Clutch and gear controller.
The ShiftFX EST consists of three main components: A state-of-the-art Active Clutch with isolation valve, which retains the standard clutch lever for operation by the rider at any time; a high-speed DC motor and fixed gear reducer that directly rotates the shift drum; and a sophisticated transmission control unit (TCU) that can be programmed to provide practically any desired shifting characteristics in either semi-automatic or automatic mode.
Active Clutch
Using a high-tech shape-memory alloy, the BDC Active Clutch is an elegant and unique design that allows electrohydraulic control of the clutch in a unit weighing less than half a kilogram. This technology has seen very limited use in automotive applications, and the BDC Active Clutch is the first commercial motorcycle application for shape-memory alloy. An added benefit of the BDC Active Clutch is that it retains the standard clutch lever that has direct connection to the clutch slave cylinder. The ShiftFX EST relies on an APTC+ auto-clutch for launching and anti-stall.
Gear Control System
The ShiftFX EST system eliminates the shift lever and ratcheting mechanism in a standard gearbox and replaces it with a patented mechanism consisting of a high-speed DC motor and gear reducer that rotates the shift drum directly. This setup allows the transmission to be shifted from any gear to any gear or to neutral, and with advanced controls mitigates the gear-jam problem commonly associated with motorcycle gearboxes. Wear on the transmission components is reduced, and the standard ratcheting system is eliminated.
Transmission Control Unit
This state-of-the-art, compact control unit is fully programmable to provide almost any shifting characteristic based on speed, load, gear position, throttle position or other parameters. The TCU also protects against engine over-revving, limits shifting into and out of neutral, and limits clutch torque transfer during shifts, reducing wear and tear on the engine components. The unit is also capable of communicating with the motorcycle's ECU via a CAN bus to control engine braking and match engine and road speeds on downshifts. Through the TCU, the ShiftFX EST can be incorporated into a motorcycle's OEM riding modes, providing specific shifting characteristics based on a selected riding mode.
Rider Interface
Overall control of the transmission is through a mode selection switch; here the rider can select either semi-automatic or full-automatic control of the transmission, or put the transmission in neutral. In semi-automatic mode, the transmission is shifted via push buttons near the left handlebar. An optional foot lever can be provided to retain a traditional shifting interface, although the transmission is still shifted electronically through the ShiftFX EST system. The manual clutch lever is retained and can be used to override the BDC system at any time.
Connection diagram shows how the various components of the ShiftFX EST are integrated into the motorcycle's existing electronic system through the TCU and the CAN bus.
In designing and developing the ShiftFX Electronic Shift Transmission, BDC had four specific goals in mind:
Retain manual clutch lever for clutch override
By using an innovative, patented Active Clutch control, ShiftFX EST retains the standard clutch lever of the manual transmission, allowing the rider to operate the clutch at any time, in either mode. This is useful for many situations, such as reduced traction, low-speed manoeuvres, aggressive launches and emergency braking.
Require no changes to existing engine architecture; utilize standard internal gearbox parts
ShiftFX EST takes advantage of the fact that every major motorcycle manufacturer produces engines with a common clutch and gearbox design; by interfacing electromechanical and electrohydraulic controls with this existing design, a system offering semi-automatic and fully automatic shifting can be produced that can be adapted easily to an existing engine's architecture and transmission components.
Minimal drivetrain losses; no hydraulic pumps
ShiftFX EST incorporates electronic control of the shift drum and clutch, requiring minimal electronic power to operate. There are no additional hydraulic pumps or drivetrain losses, and the system's electrical requirements are easily met using a typical motorcycle's charging system.
Lightweight and compact individual components
The complete BDC system adds less than 2 kilograms to a typical motorcycle's weight. The three main components of the system each weigh less than 400 grams, and some of the additional weight is offset by the elimination of the motorcycle's shift lever and ratchet mechanism.
