0
Research Papers

Effect of the Ratio Spread of CVU in Automotive Kinetic Energy Recovery Systems

[+] Author and Article Information
F. Bottiglione

Assistant Professor
e-mail: f.bottiglione@poliba.it

G. Mantriota

Full Professor
e-mail: mantriota@poliba.it
Dipartimento di Meccanica,
Matematica e Management,
Politecnico di Bari,
Bari (BA),
Viale Japigia, 182, Italy

1Corresponding author.

Contributed by the Power Transmission and Gearing Committee of ASME for publication in the Journal of Mechanical Design. Manuscript received January 25, 2012; final manuscript received March 14, 2013; published online May 2, 2013. Assoc. Editor: Avinash Singh.

J. Mech. Des 135(6), 061001 (May 02, 2013) (9 pages) Paper No: MD-12-1075; doi: 10.1115/1.4024121 History: Received January 25, 2012; Revised March 14, 2013

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.

FIGURES IN THIS ARTICLE
<>
Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.

References

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.
Barr, A., and Veshnagh, A., 2008, “Fuel Economy and Performance Comparison of Alternative Mechanical Hybrid Powertrain Configurations,” SAE Technical Paper No. 2208-01-0083.
Walsh, J., Muneer, T., and Celik, A. N., 2011, “Design and Analysis of Kinetic Energy Recovery System for Automobilies: Case Study for Commuters in Edinburgh,” J. Renewable Sustainable Energy, 3, p. 013105. [CrossRef]
Brockbank, C., 2007, “Full Toroidal CVT in a Mechanical Hybrid Configuration,” International CTI Symposium, Innovative Automotive Transmissions, Berlin, Germany.
Boretti, A., 2010, “Improvements of Vehicle Fuel Economy Using Mechanical Regenerative Braking,” SAE Paper No. 2010-01-1683.
Brockbank, C., 2010, “Development of Full-Toroidal Traction Drives in Flywheel Based Mechanical Hybrids,” CVT 2010, CVT Hybrid International Conference, Maastricht, The Netherlands, pp. 163–169.
Boretti, A., 2010, “Improvements of Truck Fuel Economy Using Mechanical Regenerative Braking,” SAE Paper No. 2010-01-1980.
Boretti, A., 2010, “Coupling of a KERS Power Train and Downsized 1.2TDI Diesel or a 1.6TDI-JI H2 Engine for Improved Fuel Economies in a Compact Car,” SAE Paper No. 2010-01-2228.
Boretti, A., 2010, “Modeling of Engine and Vehicle for a Compact Car With a Flywheel Based Kinetic Energy Recovery Systems and a High Efficiency Small Diesel Engine,” SAE Paper No. 2010-01-2184.
Fellows, T. G., and Greenwood, C. J., 1991, “The Design and Development of an Experimental Traction Drive CVT for a 2.0 Litre FWD Passenger Car,” SAE Technical Paper Series, Paper No. 910408.
Greenwood, C. J., “An Energy Recovery System for a Vehicle Driveline,” International Patent No. WO 2009/141646A1.
Brockbank, C., and Body, W., 2010, “Flywheel Based Mechanical Hybrid System; Simulation of the Fuel Consumption Benefits of Various Transmission Arrangements and Control Strategies,” Proceedings of the ASME 2010 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference IDETC/CIE 2010, Aug. 15–18, Montreal, Quebec, Canada.
Mangialardi, L., and Mantriota, G., 1999, “Power Flows and Efficiency in Infinitely Variable Transmissions,” Mech. Mach. Theory, 34(7), pp. 973–994. [CrossRef]
Mantriota, G., 2002, “Performances of a Series Infinitely Variable Transmission With Type I Power Flow,” Mech. Mach. Theory, 37(6), pp. 579–597. [CrossRef]
Mantriota, G., 2002, “Performances of a Series Infinitely Variable Transmission With Type II Power Flow,” Mech. Mach. Theory, 37(6), pp. 555–578. [CrossRef]
Mantriota, G., 2001, “Theoretical and Experimental Study of Power Split Continuously Variable Transmission System, Part 1,” Proc. Inst. Mech. Eng., Part D, 215(D7), pp. 837–850. [CrossRef]
Mantriota, G., 2001, “Theoretical and Experimental Study of Power Split Continuously Variable Transmission System, Part 2,” Proc. Inst. Mech. Eng., Part D, 215(D7), pp. 851–864. [CrossRef]
Mantriota, G., 2001, “Power Split Continuously Variable Transmissions With High Efficiency,” Proc. Inst. Mech. Eng., Part D, 215(D3), pp. 357–368. [CrossRef]
Bottiglione, F., and Mantriota, G., 2011, “Reversibility of Power-Split Transmissions,” J. Mech. Des., 133(8), p. 084503. [CrossRef]
Murphy, I., 2009, “Key Factors in Optimising the Performance of Flywheel Hybrid Systems,” Low Carbon Vehicles 2009: Institution of Mechanical Engineers Conference, May 2009.
Durack, M. J., “Full Toroidal Traction Drive,” World Intellectual Property Organization, International Publication No. WO 2011/041851 A1.
Carbone, G., De Novellis, L., and Mangialardi, L., 2012, “Traction and Efficiency Performance of the Double Roller Full Toroidal Variator: A Comparison With Half- and Full-Toroidal Drives,” ASME, J. Mech. Des., 134(7), p. 071005. [CrossRef]
Bottiglione, F., Carbone, G., De Novellis, L., Mangialardi, L., and Mantriota, G., 2013, “Mechanical hybrid KERS based on toroidal traction drives: an example of smart tribological design to improve terrestrial vehicle performance,” Adv. Tribol., Vol. 2013, a.n. 918387. [CrossRef]
Moro, D., Cavina, N., Trivić, I., and Ravagnoli, V., 2010, “Guidelines for Integration of Kinetic Energy Recovery System (KERS) Based on Mechanical Flywheel in an Automotive Vehicle,” SAE Technical Paper No. 2010-01-1448.
Soltic, P., and Guzzella, L., 2001, “Performance Simulations of Engine-Gearbox Combinations for Lightweight Passenger Cars,” Proc. Inst. Mech. Eng., Part D, 215, pp. 259–271. [CrossRef]
Bottiglione, F., and Mantriota, G., 2008, “MG-IVT: An Infinitely Variable Transmission With Optimal Power Flows,” ASME, J. Mech. Des., 130(11), p. 112603. [CrossRef]
Carbone, G., Mangialardi, L., and Mantriota, G., 2004, “A Comparison of the Performances of Full and Half Toroidal Traction Drives,” Mech. Mach. Theory, 39, pp. 921–942. [CrossRef]

Figures

Grahic Jump Location
Fig. 1

Schematic of the driveline of the mechanical hybrid vehicle. Sections of the driveline are tagged with numbers. FR is the Fixed Ratio final drive of the vehicle driveline, FM is the Final Multiplier. The variator can be of two types: single-unit mechanical CVT (toroidal traction drive for instance) or PS-CVT architecture, where PG is the planetary gear. The KERS is plugged in the vehicle propshaft through a friction clutch. A second clutch (not shown in the figure) can disconnect the FM from the variable drive when the flywheel is in idle rotation.

Grahic Jump Location
Fig. 4

The federal test procedure driving schedule. The first part is the urban FTP-75, followed by the extra-urban HFET driving schedule.

Grahic Jump Location
Fig. 2

Schematic of the power flows (arrows) in the shunted CVT architecture. PG is the planetary gear drive, FR is the fixed-ratio drive. In the forward mode or direct operation the power input is the shaft 4 and the output is the shaft 3. In the reverse operation, the power input is the shaft 3 and the output is the shaft 4.

Grahic Jump Location
Fig. 3

The efficiency of PS-CVT as a function of the τPS with internal power recirculation of (a) type I and (b) type II in direct (thick dashed line) and reverse (thick continuous line) operation. The efficiency of the CVT (thin line) is constant ηCVT=0.92, the lower and upper bounds of the CVT ratio are τCVTmin=0.4,τCVTmax=2.5, the lower and upper bounds of the PS-CVT ratio (vertical thin dashed lines) τPSmin=0.2,τPSmax=2.5 corresponding to rrPS=12.5, and ηFR=0.97.

Grahic Jump Location
Fig. 6

KERS boost as a function of the τPSmin in FTP-75 driving shedule. The variator is ideal (unitary efficiency) in this simulation. The horizontal dotted line emphasizes the value given by the system with direct drive CVT (marked with a dot).

Grahic Jump Location
Fig. 5

The average power loss in the clutch as a function of the minimum value of the τPS in FTP-75 driving schedule. The variator is ideal (unitary efficiency) in this simulation. The horizontal dotted line emphasizes the value given by the system with direct drive CVT (marked with a dot).

Grahic Jump Location
Fig. 7

(a) The KERS boost and (b) the round-trip efficiency in the FTP-75 driving schedule as a function of the lower bound of the PS-CVT ratio τPSmin. The results are shown for internal power flows of types I, II, and III and the direct drive CVT. The horizontal dotted line emphasizes the value given by the system with direct drive CVT (marked with a dot).

Grahic Jump Location
Fig. 8

(a) The average power loss in the variator and (b) in the clutch in the FTP-75 driving schedule as a function of the lower bound of the PS-CVT ratio τPSmin. Internal power flows of types I, II, and III and direct drive CVT are considered. The horizontal dotted line emphasizes the value given by the system with direct drive CVT (marked with a dot).

Grahic Jump Location
Fig. 9

The KERS boost as a function of the lower bound of the variable drive ratio τPSmin at different values of the upper bound of the flywheel angular velocity. In the comparison the maximum energy which can be stored in the flywheel is kept constant and equal to 178 kJ. Simulations have been performed with PS-CVT with power flow of type II or III and with direct drive CVT.

Grahic Jump Location
Fig. 10

(a) The KERS boost and (b) the round-trip efficiency in the FTP-75 driving schedule as a function of the lower bound of the PS-CVT ratio τPSmin. The results are shown considering the internal power circulations of types I, II, and III and the direct drive CVT (marked with a dot). In these simulations, the CVT efficiency has been supposed constant and equal to 0.97.

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In