Improvement of fuel economy in power-shift automated manual transmission through shift strategy optimization - An experimental study

In this paper, an optimal gear shifting control strategy based on Dynamic Programming (DP) for a vehicle equipped with a Power-Shift Automated Manual Transmission (PS-AMT) is proposed in order to explore the potential fuel savings. Simulation results on the city part of the New European Drive Cycle (NEDC), called ECE cycle, reveal that the relative fuel economy improvement can be reached up to 15.4% by applying DP shifting strategy compared to the case of applying a prescribed gear shift schedule. A forward facing dynamic power train model and control system are designed and developed for the prototype PS-AMT vehicle in order to validate the system modeling and shifting algorithm implementation. The test results of the prototype vehicle on the roller bench show that 11.2% improvement of fuel economy is achieved. It can be concluded that significant potential fuel savings can be obtained by optimal gear shift control and the proposed design method is consistent

Analyzing the performance index for a hybrid electric vehicle

The definition of a performance index for the optimization design and optimal control problem of a Hybrid Electric Vehicle is not often considered and analyzed explicitly. In literature, there is no study about proposing a method of building or evaluating whether a performance index is appropriate. In this paper a method of objectively analyzing the performance index for the optimal control problem of a parallel Hybrid Electric Vehicle is introduced. The correlations and interdependencies among the objectives of the performance index are addressed by using the Singular Value Decomposition method. It is found that a simplified performance index consisting of fuel consumption and comfort can be obtained without sacrificing the vehicle performance compared to the case with the original one including fuel consumption, comfort and driveability

A study on automotive drivetrain transient response to ‘clutch abuse’ events

This is an Open Access article licensed under a Creative Commons Attribution 3.0 Unported Licence.The optimal design of driveline components in passenger vehicles requires detailed knowledge of the effects that load case scenarios introduce into the system. In many cases the latter are difficult to obtain, since a large number of tested cases are required experimentally. Excessive torque loading often occurs during driveline ‘clutch abuse’ events, where the clutch is suddenly engaged and a transient power wave is transmitted across the driveline. This work details the development and validation of a numerical tool, which can be used to simulate such abuse scenarios. The scenario examined consists of a sudden clutch engagement in first gear in a stationary vehicle. The numerical model is validated against experimentally measured torque data, showing fairly good agreement. A set of parametric studies is also carried out using a numerical tool in order to determine the driveline parameters of interest, which affect the generated torque amplitudes