Numerical analyses of a hydraulic hybrid powertrain system for a transit bus

Abstract

A dynamic programming optimization algorithm has been applied on a transit bus model in MATLAB in order to assess the fuel economy improvement potential by implementing a hydraulic hybrid powertrain system. The numerical model parameters have been calibrated using experimental data obtained on a Belgrade's public transport bus. This experiment also provided the representative driving cycle on which to conduct simulation analyses. Various functional parameters of a hydraulic hybrid system have been evaluated for obtaining the best possible fuel economy. Dynamic programming optimization runs have been completed for various hydraulic accumulator sizes, preload values and accumulator foam quantities. It has been shown that a fuel economy improvement of 28% can be achieved by implementing such a system.

A Neural Network-Based Control Algorithm for a Hydraulic Hybrid Powertrain System

“…Rolling friction coefficients, aerodynamic friction coefficients, brake torque limits maps (Figure 1) and the engine BSFC (Figure 2), along with data concerning the gearbox, hydrodynamic torque converter and various drivetrain components among others, have been implemented into the base model. Detailed procedures and values can be found in [2,3,4]. Compared to electrical batteries, hydro-pneumatic accumulators are characterized by a higher specific power and a lower specific energy.…”