The Double Roller Full Toroidal Variator: A Promising Solution for KERS Technology
We have analyzed in terms of efficiency and traction capabilities a recently patented toroidal traction drive variator: the so-called double roller full toroidal variator (DFTV). We compare its performance with the single roller full-toroidal variator (SF
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Abstract We have analyzed in terms of efficiency and traction capabilities a recently patented toroidal traction drive variator: the so-called double roller full toroidal variator (DFTV). We compare its performance with the single roller fulltoroidal variator (SFTV) and the single roller half-toroidal variator (SHTV). Interestingly, the DFTV shows an improvement of the mechanical efficiency over a wide range of transmission ratios, and in particular at the unit speed ratio as in such conditions the DFTV allows for zero-spin, thus strongly enhancing its traction capabilities. The very high mechanical efficiency and superlative traction performance of the DFTV have been exploited to investigate the performance of a flywheel based Kinetic Energy Recovery Systems (KERS) where the efficiency of the variator plays an important role in determining the overall energy recovery performance. The energy boost capabilities and the overall round trip efficiency have been calculated for every type of mechanical drive and a comparison has been discussed. The results suggest that SHTV and DFTV are the best choices to improve the energy recovery potential of the mechanical KERS. Keywords Continuously variable transmissions Kinetic energy recovery systems
Toroidal traction drives
F2012-C03-006 G. Carbone (&) F. Bottiglione L. Mangialardi G. Mantriota Dipartimento di Meccanica Matematica e Management, Politecnico di Bari, Bari, Italy e-mail: [email protected] G. Carbone Center of Excellence in Computational Mechanics, Politecnico di Bari, Bari, Italy L. De Novellis Faculty of Engineering and Physical Sciences, University of Surrey, Guildford, UK
SAE-China and FISITA (eds.), Proceedings of the FISITA 2012 World Automotive Congress, Lecture Notes in Electrical Engineering 193, DOI: 10.1007/978-3-642-33744-4_21, Ó Springer-Verlag Berlin Heidelberg 2013
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1 Introduction Present developments in the automotive field are related to the design of drive-trains with the aim of improving the exploitation of the thermal engine, according to the requirements of reduction of fuel consumption and polluting emissions [1–3]. To achieve these targets, the hybrid power trains are being studied and developed. Among all possibilities, some research works claim that mechanical hybrids are more efficient and give the greatest advantages in terms of reduction of fuel consumption and polluting emissions. Several investigations have been made to estimate the effective benefits that such systems can give in mainstream cars and trucks at the present state-of-the-art. Computational results demonstrate that a fuel economy improvement up to 25 % can be obtained in mainstream passenger cars and trucks, which can also be improved further with engine downsizing [4–7]. Continuously variable drives are the core of mechanical hybrids. Chain/belt Continuously Variable Transmissions (CVTs) have been widely studied either theoretically either experimentally [8–10]; however, limitations of the maximum transmittable torque and of co
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