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 model in drivetrain simulations. Specifically, a dynamic band brake model is implemented to predict the up-shift behaviour of a four-speed AT system under various operating conditions. Simulation results are qualitatively validated with experimental data obtained from a dynamometer test stand. The dynamic band brake model enhances the shift predictability of a drivetrain model and potentially allows analytical evaluation of shift quality and control strategy.

On emulating engine and vehicle transient loads for transmission-in-the-loop experiments

“…During the second phase, called the inertia phase, the clutch capacity of the on-coming clutch increases until it is engaged, and this mechanical coupling reduces the speed of the engine. However, in order to have a smooth shift, the engine torque during this phase is reduced by spark retardation [21,22]. Since the engine does not contain a combustion model, the spark retardation command is converted into a torque-cut command, and applied to the engine mean torque at the beginning of the inertia-phase, as informed by the transmission controller.…”

Systematic gear shift model for an automatic-transmission-based parallel hybrid electric vehicle

“…In this research, the equivalent moment of inertia of the output shaft is selected to be 133 kg m 2 by considering the fact that the output shaft is connected to a vehicle driveline system. 9 The reduced-row echelon form of matrix A a becomes …”

“…Some researchers have focused on the development of a shift model based on direct solution of the governing equations. 9,10 On the other hand, numerous object-oriented graphical-user-interface-based simulation software packages such as AMESim Ò , EASY5 Ò , SimDriveline TM , and Advanced Vehicle Simulator (ADVISOR) have been developed recently for the modelling and analysis of advanced powertrain systems. It is, however, necessary to build a complete gear shift model since the aforementioned simulation tools do not provide the dynamic transient phenomenon during a gear shift as well as sufficient information for designing a shift controller, as illustrated in Figure 2(a), although they have been successfully validated in evaluating vehicle performance such as the fuel consumption.…”

Engine torque pulse and wheel slip emulation for transmission-in-the-loop experiments

“…During the second phase, called the inertia phase, the clutch capacity of the on-coming clutch increases until it is engaged, and this mechanical coupling reduces the speed of the engine. However, in order to have a smooth shift, the engine torque during this phase is reduced by spark retardation [20], [21]. Since the engine does not contain a combustion model, the spark retardation command is converted into a torque-cut command, and applied to the engine mean torque at the beginning of the inertia-phase, as informed by the transmission controller.…”