Search Results

Starting with NECAR 1 in 1994 DaimlerChrysler has developed a series of fuel cell (FC) concept vehicles to prove the practicability of FC technology in mobile applications. Within the next two years the first buses (2003) and passenger cars (2004) will be given into customer hands indicating the start of a new phase within FC technology development. Among DaimlerChrysler's concept vehicles, Necar 3 and Necar 5 are using methanol as fuel. Methanol is an interesting option, because its storing is much easier than the storage of pure hydrogen. In a rather simple process and at low temperature it can be reformed into a hydrogen rich gas. This paper is dealing with the simulation and the design of methanol FC powertrains with Matlab/Simulink®. The results are fuel consumption with special regard to the operating strategy and the dimensioning of the FC powertrain's components.

The development of an energy management system for a fuel cell hybrid electric vehicle (FCHEV) based on single step dynamic programming (SSDP) is described in this paper. The SSDP method is used to minimize a weighted cost of hydrogen and battery degradation with the latter being controlled to carry out charge-depleting (CD) as well as charge-sustaining (CS) strategies with simple lower bound enforcement or relaxation. The problem formulation accounts for the power balance at each stage, the fuel cell and battery power limits, the battery state-of-charge limits, and the ramp-rates constraints of the fuel cell and battery. Its chief advantage over forward dynamic programming (DP) or other formal optimization methods is that it does not require the speed forecast of the whole drive cycle but requires only a one-step-ahead speed forecast.

Vehicle-cybernetic covers the area of information and control systems in the vehicle. The importance of this area for vehicle engineering is increasing because of two reasons: - With microelectronics, a technology has become available for a development which offers completely new possibilities for the realisation of complex cybernetic systems in the vehicle. - The interdisciplinary area of the control and data-processing interaction between driver, vehicle and environment is the one which has the highest potential of improvements in primary safety, economy and consistence with the environment, because each of the single systems have been largely optimized in the course of its long time of development. In the contribution the projects from the area of vehicle-cybernetics are presented in a systematical analysis.

An optimal energy management system is presented to minimize hydrogen utilization over driving cycles using forward dynamic programming (FDP). The objective is to minimize the cost of hydrogen with the battery cost being used as a parameter to carry out charge-depleting as well as charge-sustaining strategies along with bound enforcement or relaxation. The problem formulation accounts for the power balance at each stage, the power limits, the state-of-charge limits, and the ramp rates constraints of the fuel cell and battery. FDP is selected because it can easily cater for non-linearity in system cost and constraints. It employs heuristic rules to limit the number of states at each stage and is shown to be a very fast algorithm using simple computations and thus may easily lend itself for real-time implementation.