Poster Presentation

Mr. Meisam Amiri, Vehicle, Fuel and Environment Research Institute, Iran
Mr. Hassan Nehzati, University of Tehran, Iran
Mr. Ali Manteghi, University of Tehran, Iran

With the stricter limitations on both fuel consumption and air pollution, the benefits of Hybrid Electric Vehicles (HEV) are becoming more evident than ever. In this paper a Fuzzy Logic Controller (FLC) for a series hybrid city bus is developed. The FLC is chosen because of the need for a controller for a nonlinear, multi-domain, and time varying plant with multiple uncertainties. The implemented controller is a fuzzy based power follower controller which takes demanded power (the power needed by driver and auxiliary loads) and battery State of the Charge (SoC) as inputs and returns the power of ICE-Generator unit as the output. Because the controller is designed for a real bus, there were some limitations which have to be considered in design procedure. The chosen ICE (Mercedes-Benz, OM 906 LA, 205 kW) has a wide optimum operating region and it can supply wide range of demanded power solely with maximum accessible overall efficiency, so it is possible to have minimum use of batteries and in return increase batteries life and decrease losses due to charging and discharging the batteries. The generator (Siemens 1FV5139-6WS28) impose some constraints because of its limitations for maximum torque and power. Also the allowable maximum charge and discharge currents of batteries (Kokam SLPB100216216H) have been considered. Then working region of each component has been defined according to overall characteristic of all components. The controller is developed to control the engine operating points in its optimal region, prevent engine stall duo to generator high torque, supply the demanded power by getting the minimum possible use of batteries; and maintain the SoC of batteries in their efficient region. The FLC used here is of the Mamdani type which takes its input variables, fuzzificate them with designed Membership Functions (MFs), and then by the means of fuzzy Rules, the output is obtained using the Centroid of Area method of defuzzification. Output of The controller has been simulated and tuned using a detailed model of bus which is implemented in a simulation program and its results have been compared with a thermostat controller. Simulation results show considerable improvement in fuel consumption, acceleration, performance, batteries life beside lower cost of hybridization. This controller is designed in the project of manufacturing the first hybrid electric bus of the middle-east at `Vehicle, Fuel and Environment Research Institute´ of University of Tehran and is going to be implemented on the bus.

Poster presentation: Future powertrain solutions