Tyng Liu

Design and modeling of a novel 6-speed dual clutch transmission system

This study provides a new concept of dual clutch transmission (DCT) system, which using one-way clutches and synchronizers compose a multi-speed mechanism. In this paper, the gear shifting processes of a general DCT system are discussed, and the mathematic equations and dynamic models of the conventional DCT system and new DCT system are established. Through a series of dynamic simulation analyses, the new DCT system reduces shifting processes so that it presents not only a fewer shifting time but also decreases the torque interruption.

Limited-slip and torque-vectoring effect of a dual continuously variable transmission

This study investigates the limited-slip and steering characteristics of a dual continuously variable transmission system. The dual continuously variable transmission is a unique final drive system composed of two continuously variable transmissions, with one continuously variable transmission connected to each rear wheel. In this study, a dynamic model of the dual continuously variable transmission system is derived, and models of the conventional final drive systems, i.e. the solid axle and the open differential, are used as benchmarks. In the simulations, the dual continuously variable transmission model, the solid axle model and the open differential model are applied to a vehicle dynamic model for split-μ road tests and a series of steering tests. According to the results of the split-μ road tests, the limited-slip function of a dual continuously variable transmission system is verified. The results of the steering tests show that different torque distributions for the inside wheels and the outside wheels while cornering can be controlled with different gain values of the continuously variable transmissions; for this reason, the application of the dual continuously variable transmission system as a torque-vectoring device is proposed, and a basic setting principle is presented. The results of this study establish a fundamental knowledge for developing the dual continuously variable transmission as an advanced final system for improving the vehicle dynamics.

Design and Analysis of a Novel Centrifugal Braking Device for a Mechanical Antilock Braking System

A new concept for a mechanical antilock braking system (ABS) with a centrifugal braking device (CBD), termed a centrifugal ABS (C-ABS), is presented and developed in this paper. This new CBD functions as a brake in which the output braking torque adjusts itself depending on the speed of the output rotation. First, the structure and mechanical models of the entire braking system are introduced and established. Second, a numerical computer program for simulating the operation of the system is developed. The characteristics of the system can be easily identified and can be designed with better performance by using this program to studying the effects of different design parameters. Finally, the difference in the braking performance between the C-ABS and the braking system with or without a traditional ABS is discussed. The simulation results indicate that the C-ABS can prevent the wheel from locking even if excessive operating force is provided while still maintaining acceptable braking performance.

Analysis of a New Mechanical Anti-Lock Brake System for Two-Wheeled Vehicles

This study aims to present an analysis on a new type of mechanical anti-lock brake system (ABS) and the device is suitable for two-wheeled vehicles, such as bicycles. Firstly, the structure of the mechanism, the principle of operation and operating stages of the device are discussed. Secondly, the force models of the system and the force equations with parameters are developed. Then, a numerical program for simulating the operation of the system is developed, and the relationship between operating force and braking force, as well as the efficiency of ABS in different situations (e.g. road friction coefficient, loading) are analyzed. Finally, the results of how each parameter affects the braking performance are discussed. In this paper, we present a complete analysis on this new mechanical ABS systematically. Through the simulation of various operating conditions, the characteristics of the system are investigated and clearly verified. It is shown that this type of mechanical ABS could be useful in some situations. However, the overall braking performance will be reduced. This new mechanical ABS might be useful with some possible modifications, and could be applied in other areas.