Abstract
Engineering Objective
Requirements for automotive application oriented PEMFCs are quite different from those for portable and stationary utilities. So importance of individual property is meaningfully different and thus system evaluation method is also different. Performance of automotive PEMFCs are usually improved in a spiral rising way during the FCV’s commercialization process, which means in some cases one performance improves while other performances remain or worsen. A direct and concise evaluation method would be of great help for the automotive engineers to do comparison, selection and optimization works during their FCV design. A testing plateform for synthesized performance evaluation and metrics measurement of PEMFC, under simulated ambient environment is also necessary.
Methodology
This paper proposed a hierarchical model to evaluate PEMFCs, which can both give a synthesized understanding on its overall performance and represent automotive powertrain’s requirement. The test platform was designed and implemented including: Hydrogen (fuel) supply, air supply and climate chamber, external electrical power input, heat exchange, hydrogen exhaust and leakage facilities. The testing platform integration was based on Virtual Instrument technology, namely the hardware are upon Nation Instruments while the software is Labview. The platform was designed to be a distributed data acquisition, with data transferred through Control area network as well as Ethercat. Testing management was implemented under Virtual instrument Standard Architecture.
Results
It is found in the hierachical model that the nine sub-performances, including power, economy, survivability, reliability, durability, power quality, transient response, safety and Environment, which are derived from automotive powertrain requirements, can represent the overall characteristics of the PEMFCs. The selected 18 most significant metrics are can also made each sub-performance quantitatively comparable. The testing platform was designed and integrated. It was able to simulate the ambient environment during survivability test, The anechoic chamber also made it possible to measure the NVH emission. Dynamic cycling was runned through programable e-load which was controlled by the testing platform. Thus the testing platform was able to measure all those metrics in the hierachical model, either directly or through calculation.
Limitations of this study
As a testing platform, the paramenters measurement accuracy were not carefully considered. Detailed signal sample methods were also not discussed.
What does the paper offer that is new in the field in comparison to other works of the author?
This paper proposed an comprehensive evluation method for automotive PEM fuel cell system as well as the testing bench, including a hierachical model and the corresponding testing platform.
Conclusions
A hierarchical model for PEMFCs comprehensive evaluation is proposed, which features a dual-layer structure: sub-performance layer and index layer. The test platform for testing items and metrics was also designed based on NI virtual instrument technology.
KEYWORDS : Proton exchange membrane fuel cell system, Hierarchical model, Comprehensive evaluation, test bench development, virtual instrument.