Affiliation:
1. Assistant Professor e-mail:
2. Full Professor e-mail: Dipartimento di Meccanica, Matematica e Management, Politecnico di Bari, Bari (BA), Viale Japigia, 182, Italy
Abstract
The Kinetic Energy Recovery Systems (KERS) are being considered as promising short-range solution to improve the fuel economy of road vehicles. The key element of a mechanical hybrid is a Continuously Variable Unit (CVU), which is used to drive the power from the flywheel to the wheels and vice versa by varying the speed ratio. The performance of the KERS is very much affected by the efficiency of the CVU in both direct and reverse operation, and the ratio spread. However, in real Continuously Variable Transmissions (CVT), the ratio spread is limited (typical value is 6) to keep acceptable efficiency and to minimize wear. Extended range shunted CVT (Power Split CVT or PS-CVT), made of one CVT, one fixed-ratio drive and one planetary gear drive, permit the designer to arrange a CVU with a larger ratio spread than the CVT or to improve its basic efficiency. For these reasons, in the literature they are sometimes addressed as devices for proficient application to KERS. In this paper, two performance indexes have been defined to quantify the effect of the ratio spread of PS-CVT on the energy recovery capabilities and overall round-trip efficiency of KERS. It is found that no substantial benefit is achieved with the use of PS-CVT instead of direct drive CVT, because the extension of the speed ratio range is paid with a loss of efficiency. It is finally discussed if new generation high-efficiency CVTs can change the scenario.
Subject
Computer Graphics and Computer-Aided Design,Computer Science Applications,Mechanical Engineering,Mechanics of Materials
Reference28 articles.
1. Cross, D., and Brockbank, C., 2009, “Mechanical Hybrid System Comprising a Flywheel and CVT for Motorsport and Mainstream Automotive Applications,” SAE Technical Paper No. 2009-01-1312.
2. Barr, A., and Veshnagh, A., 2008, “Fuel Economy and Performance Comparison of Alternative Mechanical Hybrid Powertrain Configurations,” SAE Technical Paper No. 2208-01-0083.
3. Design and Analysis of Kinetic Energy Recovery System for Automobilies: Case Study for Commuters in Edinburgh;J. Renewable Sustainable Energy,2011
4. Brockbank, C., 2007, “Full Toroidal CVT in a Mechanical Hybrid Configuration,” International CTI Symposium, Innovative Automotive Transmissions, Berlin, Germany.
5. Boretti, A., 2010, “Improvements of Vehicle Fuel Economy Using Mechanical Regenerative Braking,” SAE Paper No. 2010-01-1683.
Cited by
27 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献