Wrightbus and Torotrak have been demonstrating at UK trade show Coach & Bus Live 2015 the results of a joint collaboration to reduce bus emissions.
Torotrak has fitted its mechanical kinetic energy recovery system to the Wrightbus StreetLite, which uses a flywheel to store wasted energy on a short-term basis that can be deployed under load.
The British engineering company says that its mechanical hybrid system represents a much cheaper option for manufacturers, using commonly available materials and avoiding the need for replacement batteries during service life.
“Inner-city clean air objectives will continue to tighten, making increased uptake of hybrid buses crucial for the development of a low carbon public transport network,” said Tobias Knichel of Torotrak.
The so-called Flybrid system fitted to the Wrightbus demonstrators is situated parallel to the transmission and transmits power to the rear axle through a secondary propshaft. Energy is captured under deceleration and stored in the carbon-fiber and steel flywheel, and used to accelerate the bus to reduce the load on the IC engine.
“The Flybrid system for buses has been extensively validated, having undergone a rigorous durability testing programme – its life cycle of 1,000,000km, 40,000 operational hours or 8,000,000 charge/discharge cycles is aligned with the anticipated lifetime of the vehicle to which it is fitted,” continued Knichel.
October 27, 2015