Developing the Durability of a Dual-Cavity Full-Toroidal IVT Variator

Lee, Adrian P.; Newall, Jonathan; Hoshino, Teruo

doi:10.4271/2002-01-0587

Cited by 6 publications

(2 citation statements)

References 8 publications

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“…7. A ratio range of 2.64:1 was required for the twin-charged system, which is well within the capacity of most CVT systems, including traction drives [19] such as the Milner continuously variable transmission (MCVT) [20,21], the Torotrak full-toroidal variator [22], the half-toroidal variator [23], and the belt drive CVT [24]. However, this ratio range is only taking into account full-load conditions; at part load, air mass delivery requirements would be proportionally less than these, implying a further required reduction in the supercharger drive ratio.…”

Section: Cvt Ratio Rangementioning

confidence: 99%

Modelling the performance of a continuously variable supercharger drive system

Rose

Akehurst

Brace

2011

Proceedings of the Institution of Mechanical Engineers, Part D:

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This paper details a simulation-based investigation into a novel forced-induction boosting system with a centrifugal-type supercharger driven from the engine crankshaft via a continuously variable transmission (CVT). This system acts as a pre-boost to a traditional fixed-geometry turbocharger and has been identified as a possible solution to improving the low-speed engine torque and transient response of future downsized and existing turbocharged engines. The concept was modelled around an existing baseline high-speed directinjection diesel engine model featuring a variable-geometry turbocharger.Conclusions are drawn comparing the potential of the proposed system with the baseline engine in terms of the brake specific fuel consumption, and both the steady state and the transient performance. A design-of-experiments approach is applied to investigate the effects of the supercharger compressor size, the turbocharger compressor and turbine size, the CVT ratio, and the engine compression ratio on the system performance. Optimization techniques are then applied to identify the best settings for these parameters in the proposed system. Transient simulation was undertaken in a MATLAB/Simulink Ricardo WAVE co-simulation environment to develop the required control strategies for the CVT supercharger.The proposed system demonstrates a significant improvement in the low-speed engine torque and transient response of the boosting system during tip-in pedal events, which it is proposed will result in a significant improvement in the vehicle performance and driveability.

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Section: Cvt Ratio Rangementioning

confidence: 99%

Modelling the performance of a continuously variable supercharger drive system

Rose

Akehurst

Brace

2011

Proceedings of the Institution of Mechanical Engineers, Part D:

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“…However, it undergoes more severe contact conditions than the conventional transmissions so that much careful design considerations are required especially in the geometrical designs of roller and disk shapes. In case of toroidal CVT system, the torque is transmitted by three-point contacts between roller and disk which sustain all of the traction powers of ~200hp [2,3]. Therefore, the contact points should be well controlled in order to have long endurance and good operational performance of CVT system.…”

Section: Introductionmentioning

confidence: 99%

A Study on the Contact Behaviors of Infinitely Variable Transmission System with Full Toroidal Shapes of Disks

Jang

Choi

2005

KEM

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The torque of the continuously variable transmission system with friction drive mechanism is transmitted by contacting roller with input and output disks. For the higher transmitted torque, it is necessary to apply large load in order to get higher friction force, which in turn generates severe high stress on the contact surfaces of roller and disks. The toroidal type CVT system has simple component arrays that have three contact points between roller and each input or output disk to get the torque transmitted. However, compact assembly design of the three sets of rollers contacting with input and output disks needs the roller to stay with unsymmetrical angled position with each other. Therefore, the contact shapes between roller and disk vary according to the transmission ratio and should be investigated to avoid the excessive contact stress over than ~1.8 GPa. In this study, the contact geometries of roller and disks in the toroidal type CVT system are computed during the gear ratios. The contact area of which the size depends on the material elasticity, curvatures of roller and disk, and applied load are all of elliptic shapes because of the convex and concave curvatures of roller and disk shapes, respectively. From the computed results considering the size of roller diameter, roller stroke and applied load, it is found that the shapes of contact area changes the sizes of major and minor elliptical diameters in the rolling direction during the gear ratios due to the unsymmetrical angled position of roller.

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