The role of variable drive technology in realising fuel economy and emissions improvements

摘要

Belt and chain derived variable drive transmissions are viewed as mature technology in the automotive passenger car sector. Thus far, the technology has not been seen in applications larger than this. A new and proven variable drive technology, called full-toroidal traction drive has emerged which provides significantly greater breadth of application with the capability to cover vehicles spanning lawn and garden equipment through to full-sized haulage trucks. With the benefit of many years of development and commercialisation, this new technology is seen by industry adopters as having met the crucial implementation-ready threshold. The paper describes the development of this technology and its generic advantages including fuel economy improvements and emissions reductions. For example, when applied to a European mid-sized bus, as a main drive transmission, the technology has been proven to achieve a fuel saving of 19% over the official UK bus test cycle when compared to the standard production model. The barriers to wider application of variable drive technology have historically been mechanical efficiency and scalability. The unique characteristics of full-toroidal traction drive overcome these barriers to deliver mechanical efficiency with scale. Using this unique combination of characteristics, full-toroidal traction drive technology is being used as the platform for new transmissions in a large range of applications as well as fields of use. They comprise: main drive transmissions, auxiliary drives (such as supercharger drives) and mechanical hybrid drives The paper explains the particular benefits of full-toroidal traction drive technology in each of these applications, with particular focus on two examples of supercharger drives, and variable drives for Kinetic Energy Recovery Systems.