Human Friendly Transmission
The Human Friendly Transmission is the name of a proprietary Continuously variable transmission made by Honda for some of its motorcycles. It has been used on the Honda DN-01 and on the EVO6 concept motorcycle.
The electronically controlled automatic transmission system is unlike more familiar belt-driven CVT systems used on scooters, nor does it have a torque converter, typical of automotive applications. Instead it is a hydrostatic drive that employs a variable displacement axial piston pump with a variable-angle swashplate. Apart from Honda, this type of system has not been seen in road-going consumer motor vehicles, though it is familiar in industrial applications and heavy equipment such as forklifts and the US Air Force's MJ-1 bomb lift truck, in use since the 1950s. Honda has also dabbled in this technology since the 1950s. It appeared on their 2001 FourTrax Rubicon 4-wheel, off-road ATV.
The electronic controls allow the motorcycle to be operated in three modes: Drive, Sport and Manual. In Drive and Sport, it functions much like a CVT scooter, with infinitely variable gearing upshifted and downshfited automatically for what the system determines to be optimal performance. Unlike a scooter, engine braking is always available when decelerating. The difference between Drive and Sport modes is that Drive is optimized for economy while Sport is more responsive. In Manual mode, the transmission operates in one of six discrete gears chosen by the rider by pushing a plus/minus button on the left handlebar. It feels much like a normal motorcycle, including hitting the rev limiter at the top of each gear, but the ECU prevents upshifting and downshifting too soon. In all modes, it automatically returns to the lowest gear when stopped. It is also possible to switch into neutral while stopped, unlike a scooter.
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- Carpenter, Susan (3 April 2009), "The Honda DN-01: automatic + motorcycle = smooter?", The Los Angeles Times; Up to Speed; The latest buzz in L.A.'s car culture, archived from the original on 2009-04-08, retrieved 11 February 2014
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- US Air Force, U.S. Air Force Fact Sheet MJ-1 LIFT TRUCK, National Museum of the US Air Force, retrieved 14 November 2009
- Motorcycle Picture Book | HFT (Human-Friendly Transmission) Honda's animated visualizations of HFT operation (Adobe Flash).