ENGINEERING JOURNAL No - eB Catalog

1 Control Concepts of Continuously Variable Transmissions (CVT). R. FUCHS Y. HASUDA. Y. ROTHENBUEHLER K. MATSUMOTO. This paper gives a general overview of friction type CVTs in automotive powertrain emphasizing on the two concepts of ratio and torque control. These are described and compared from different perspectives, starting with an introduction to their most common designs, to considerations of the basic dynamics and mechanism of interaction observed in CVT powertrains. Distinctions between the two systems are identified, resulting in the establishment of formal definitions of ratio control CVT (RC/CVT) and torque control CVT (TC/CVT). This paper is completed with a new classification of transmissions including, at its root, a first separation between ratio and torque control.

2 Key Words: CVT, IVT, torque control, interaction, ratio control, traction, friction. 1 .. 3 .. CVT . CVT .. CVT .. EHL .. CVT EHL .. F t . CVT. l F l . CVT 3 . 32 JTEKT ENGINEERING JOURNAL No. 1001 (2006).. Ft l x . u F . l x . u a .. a .. CVT .. u . x .. u x Fixed Secondary Sheave CVT Pulley Belt CVT Movable Sheave Movable Sheave Primary Pulley Traction Coefficient Fixed Sheave Tilt Output 0 Disc 0 5 10 15 (End load). Input Slip Ratio Disc Roller Hydraulic Offset Piston An example of a traction curve for the full toroidal variator CVT.. Ratio control CVT Top Belt type, Bottom Half-toroidal type . CVT.. CVT RC/CVT . CVT . CVT TC/CVT . 2 . 1 3 2.. JTEKT ENGINEERING JOURNAL No. 1001 (2006) 33.. T i xi T o xo 3xo CVT. 3To Engine ucvt . CVT . CVT powertrain model Reaction Force Piston Position.

3 Tilt Caster Angle 5 CVT . Roller . Reaction . Force 3 CVT . Input Disc Output Disc Reaction (Endload) . Force F c r g . CVT xint xext . Torque control CVT Full toroidal type . F t .. RC/CVT TC/CVT .. CVT Ft Fa . CVT . CVT . CVT .. 3xo 3 . RC/CVT L1 L3 L1 .. 3T o . CVT . TC/CVT L2 . 3T o . CVT . CVT L3 . CVT .. RC/CVT TC/CVT .. CVT .. Tenberge . 34 JTEKT ENGINEERING JOURNAL No. 1001 (2006).. Carbone .. CVT .. RC/CVT . CVT . CVT . Fc . Text xext . Inertia Ft Traction CVT . L2 L1 . L3 xint Internal . rg Fa Dynamics . Torque .. CVT. 10 . CVT . TC/CVT . Generalized mechanism of interaction in friction type . CVT.. CVT CVT . CVT F a CVT . T ext . F a .. CVT .. RC/CVT TC/CVT . 11 14 . CVT .. CVT .. JTEKT ENGINEERING JOURNAL No. 1001 (2006) 35.. 2 .. 15 .. TC/CVT . RC/CVT.

4 2 . CVT . CVT TC/CVT . RC/CVT . TC/CVT RC/CVT .. RC/CVT . TC/CVT TC/CVT . RC/CVT .. TC/CVT .. Automotive Transmission Ratio Control Torque Control Discrete Ratio Continuous Ratio Continuous Ratio Automated Manual Automatic Friction Type Ratcheting Hydrostatic Friction Type Manual - 4-Speeds - Automated - 3-Speeds - Pulley-Belt - Crank CVT - Full-Toroidal - 5-Speeds - Power Shift - 4-Speeds - Pulley-Chain .. - Double Clutch .. - Half-Toroidal - 8-Speeds - Cone-Type .. CVT.. Classification of automotive transmissions emphasizing the fundamental difference between ratio and torque control 36 JTEKT ENGINEERING JOURNAL No. 1001 (2006).. Elsevier 2002. K. Hebbale, M. Carpenter, Control of the Geared R. D. Fuchs, Y. Hasuda, I. B. James, Full Toroidal Neutral Point in a Traction Drive CVT, Proceeding IVT Variator Dynamics, SAE paper 2002-01-0586, of the American Control Conference, IEEE, Denver, March 2002.

5 USA, June 2003. H. Tanaka, Torque Control of a Double Cavity Half- R. Fuchs, Y. Hasuda, I. James, Modeling, Simulation and Validation for the Control Development of Toroidal CVT, JSAE Annual Congress Proceeding a Full-Toroidal IVT, CVT2002 Congress, VDI- no. 21-03, 95 , p. 5-8, 2003. Berichte 1709, October 2002. R. Fuchs, Y. Hasuda, I. James, Dynamic Performance Analysis of a Full Toroidal IVT - A. Theoretical Approach, CVT Congress 04 CVT-30, Sacramento, USA, September 2004. K. L. Johnson, The Strength of Surface in Rolling Contact, vol. 203, p. 151-163, IMechE 1989. Peter Tenberge, Efficiency of a Chain-CVTs at Constant and Variable Ratio - A New Mathematical Model for Very Fast Calculation of Chain Forces, Clamping Ratio, Slip and E ciency, CVT Congress 04 CVT-35, Sacramento, USA, September 2004.

6 G. Carbone, L. Mangialardi, G. Mantriota, Theoretical Model of Metal V-Belt Drives During Rapid Ratio Changing, JOURNAL of Mechanical Design, vol. 123 p. 111-117, ASME, March 2001. G. Carbone, L. Mangialardi, G. Mantriota, The Influence of Pulley Deformations on the Shifting Mechanism of Metal Belt CVT, JOURNAL of Mechanical Design, vol. 127 , ASME, January 2005. R. Pfiffner, Optimal Operation of CVT-Based . Powertrains, PhD thesis, ETH. Diss. , 2001. T. Yamamoto, T. Osidari, M. Nakano, Improvement of Loading Cam Performance in a Toroidal CVT, JSAE Review 23, 481-487, 2002. Bras Vroemen, Component Control for The Zero Inertia Powertrain, PhD thesis, TuE, 2001. H. Vahabzadeh, S. M. Linzell, Modeling, Simulation .. and Control Implementation for a Split-Torque, R. FUCHS Y.

7 HASUDA Y. ROTHENBUEHLER. Geared Neutral, Infinitely Variable Transmission, SAE paper 910409, April 1991. B. Veenhuizen, B. Bonsen, T. Klaassen, K. van de Meerakker, H. Nijmeijer, F. Veldpaus, Simulated Behavior of a Vehicle with V-Belt Type Geared Neutral Transmission with Variator Slip Control, JOURNAL of Automobile ENGINEERING -Part D, 219 5 . , 1, 2005.. T. Osumi, K. Ueda, H. Nobumoto, M. Sakaki, T.. Fukuma, Transient Analysis of Geared Neutral K. MATSUMOTO. Type Half-Toroidal CVT, JSAE Review 23 p. 49-53, .. JTEKT ENGINEERING JOURNAL No. 1001 (2006) 37.