August 24, 2004 - Honda has developed a 50cc hybrid scooter prototype that offers reduced emissions, exceptional fuel economy, and ample storage space. Employing both an internal combustion engine and an electric motor, the new prototype takes Honda one step closer to a mass-market hybrid scooter.

The new prototype features an alternating current generator (ACG) with an idle stop function and the Honda PGM-FI electronic fuel injection system. In addition to an electronically controlled belt converter and a range of Honda environmental technologies, the new scooter features a dual series and parallel hybrid powertrain with a direct rear-wheel drive electric motor. Thanks to a compact power system and a rechargeable nickel hydrogen battery located under the front cowl, the hybrid scooter is about the same size as the Dio Z4, a standard-size 50cc scooter, and is only 10 kg heavier.

The hybrid scooter's internal combustion engine and direct rear-wheel-drive electric motor function in two distinct modes. In series mode, when riding on flat ground and when high output is not required, the engine alone powers the electric motor. In parallel mode, used during acceleration and when high output is required, the electric motor assists the engine. In parallel mode, an electronically controlled belt converter automatically selects the optimum assist ratio.

To make the most efficient use of energy, the hybrid system charges the battery during deceleration and whenever possible and utilizes this power when higher output is required. In addition, the scooter enters idle stop mode, when the scooter is stopped, and whenever power is not needed, during deceleration. These advanced features allow the hybrid scooter to achieve 1.6 times the fuel economy of the Dio Z4 (when riding on flat ground at 30 km/h) and to produce 37% less carbon dioxide.