Drive System Technique 

About: Drive System Technique is an academic journal. The journal publishes majorly in the area(s): Torque & Electric vehicle. Over the lifetime, 33 publications have been published receiving 260 citations.

Improvement in fuel economy for a parallel hybrid electric vehicle by continuously variable transmission ratio control

Abstract: A continuously variable transmission (CVT) ratio control algorithm is proposed to achieve the improved fuel economy of the parallel hybrid electric vehicle (HEV) by considering the HEV powertrain response lag. In this algorithm, the target CVT ratio is modified by the vehicle velocity that is estimated after the powertrain response lag. To estimate the vehicle velocity after the response lag, an acceleration map is suggested. The CVT ratio control algorithm is validated by the HEV bench tester. From experimental results, it is found that the engine operation trajectory by the modified ratio control algorithm is shifted to a more efficient region compared with those by the conventional CVT ratio control for the mild acceleration mode, which gives better fuel economy. In addition, performance simulations for the federal urban driving schedule are carried out to evaluate the effect of the response lag on the HEV fuel economy using the HEV powertrain model. The simulation results show that a better fu...

Modelling of loss mechanisms in a pushing metal V-belt continuously variable transmission. Part 1: Torque losses due to band friction:

Abstract: The power transmission efficiency of continuously variable transmissions (CVTs) based on the pushing metal belt is acknowledged to be lower than that of discrete ratio alternatives. This tends to negate the potential fuel economy benefits that are obtained by improved engine/load matching with a CVT. This series of three papers details an investigation into the loss mechanisms that occur within the belt drive as a first step to obtaining improvements in efficiency.Experimental work has been undertaken to investigate the no-load and low-load torque losses associated with a pushing metal V-belt CVT. This first paper describes a new analysis of the principal torque losses occurring in the metal belt CVT due to relative motion occurring between the belt segments and bands. The work takes into account new findings in other research and changes in the design of the metal V-belt. The torque loss model proposed in this paper is supported by experimental data from several different test procedures. A numbe...

Control strategy for a dual-mode electromechanical, infinitely variable transmission for hybrid electric vehicles

Abstract: An operating strategy is proposed for a dual-mode electromechanical, infinitely variable transmission (EVT) hybrid electric vehicle (HEV). First, network analysis is performed to evaluate the dual-mode EVT efficiency with respect to the speed ratio. It is found from the network analysis that the EVT efficiency decreases when the power circulation occurs along the electric variator and the EVT should be operated in the speed ratio region that provides a relatively high system efficiency, which requires an operating strategy from the viewpoint of the overall powertrain efficiency rather than the internal combustion engine thermal efficiency. In order to develop the operating strategy of the dual-mode EVT, dynamic equations of the HEV powertrain including the EVT are obtained and the motor torque control algorithm is designed using inversion-based control. To evaluate the performance of the operating strategy, an HEV simulator is developed on the basis of the dynamic models of the HEV powertrain usin...

Application of dynamic band brake model for enhanced drivetrain simulation

Abstract: In a modern vehicle design process, analytical tools are widely employed to complement experimental approaches for design evaluation. When effectively utilized, they lead to a reduced development time with improved vehicle performance. The development process of an automatic transmission (AT) system can benefit from an analytical representation which accurately captures AT shifting behaviours. In a typical AT system, friction components such as wet clutches and band brakes are utilized to alter planetary gear configurations for automatic shifting. Thus, an accurate representation of friction component dynamics is critical in predicting AT shifting behaviour. Engagement characteristics of friction components vary widely under different operating conditions. Although the basic engagement physics was identified in the 1970s, it is relatively recently that a predictive, yet computationally efficient model became available. This paper describes the first attempt to utilize a dynamic friction component ...

A study of thermal and mechanical behaviour for the optimal design of automotive disc brakes

Abstract: The thermal distortion induced by thermoelastic instability (TEI) results in hot spots on the surface of the brake disc. This can incur low-frequency vibration known as judder. In pad-induced squeal noise, mode coupling occurs owing to the variation in the friction coefficient between the disc and pad, inducing high-frequency noise. Through a coupled analysis of hot spots and squeal phenomena, an optimum disc and pad design can be designed for higher thermal and mechanical performance. In this study, numerical and experimental analyses are performed in accordance with disc thickness, pressurization type of caliper, and lining arc length, considering thermal and mechanical instability simultaneously. Thermal deformation and pressure distribution are calculated using a finite element analysis (FEA). For evaluating TEI performance, experiments are performed using a chassis dynamometer and a high-speed infrared camera, and the results are correlated with FEA results. A complex eigenvalue analysis is conducted to evaluate mechanical instability using an FEA. Modal testing and simulations are conducted to correlate a real model and an FE model, and the corrected simulation results are applied for a complex eigenvalue problem to analyse coupled modes according to rotor and pad shapes. The results on disc brake performances considering the disc and pad design are discussed in terms of hot spots and squeal problems.