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Rubber continuously variable transmission (CVT) belts are extensively applied in automotive industry. The tones of belt ‘whistle’ noise, which vary with belt transmission speed during low- and high-ratio operations, annoy drivers, especially when the throttle is closed and the vehicle is in motoring condition. In this study, two types of scooters with different cylinder volumes are taken as examples to cope with this problem for reducing belt noise. In the investigation, the varying order of CVT belt noise based on engine revolution speed can be exactly tracked. Thus the whistle-like noise can be confirmatively identified as CVT belt noise. Some design parameters of the CVT-belt and -structure, which influence the radiation of this annoying noise, are examined as well. To suppress CVT belt noise, some useful design modifications are made and justified.

In this paper, an integrated torque converter design process is described which improves converter performance while reduces the design cycle time and number of hardware iterations. The process utilizes a suite of tools to achieve the objectives. For quick and flexible geometry layout, the TORUS DESIGN TOOL is employed to create the underlying 2D-torus geometry with given packaging constraints. The BLADE DESIGN TOOL is subsequently used to generate 3D sheet-metal type profiles for the impeller, turbine, and reactor blades. The tool is equipped with a parametric capability for blade curvature and blade angle control to meet the performance requirements. The AIRFOIL DESIGN TOOL utilizes a sophisticated, parameterized algorithm to generate the desired airfoil shape around the reactor camber-line for improved performance.