<div class="section abstract"><div class="htmlview paragraph">As compared with other batteries, lithium-ion batteries are featured by high power density, long service life, high energy density, environmental friendliness and thus have found wide application in the area of consumer electronics. However, lithium-ion batteries for electric and hybrid electric vehicles (EVs and HEVs) have high capacity and large serial-parallel numbers, which, coupled with such problems as safety, durability, cost and uniformity, imposes limitations on the wide application of lithium-ion batteries in the EVs and HEVs. The narrow area in which lithium-ion batteries operate with safety and reliability necessitates the effective control and through the use of management of battery management system. Battery state of health (SOH) monitoring has become a crucial challenge in EVs and HEVs research, as SOH significantly affects the overall vehicle performance and life cycle. This paper presents both cycling and calendar aging at high and low temperatures. In the proposed model the calendar aging is represented as a function of time, storage temperature and state-of-charge (SOC). On the other hand, cycle aging is represented as a function of energy throughput, cell temperature and C-rate. The cycling and calendar aging models are later combined to formulate an empirical cell-level aging model. The performance of the cell-level empirical aging model is validated by comparing it with the aging test data for different driving scenarios. The aging prediction from the empirical aging model shows very good agreement with the test data with a maximum normalized root mean squared error (RMSE) of 0.85%</div></div>
Ionization in internal combustion engines produces a signal indicative of in-cylinder conditions that can be used for the feedback electronic control of the engine, to meet production goals in performance, fuel economy and emissions. Most of the research has been conducted on carbureted and port injection spark ignition engines where the ionization mechanisms are well defined. A limited number of investigations have been conducted on ionization in diesel engines because of its complex combustion process.
In this study, a detailed ionization mechanism is developed and introduced in a 3-D diesel cycle simulation computational fluid dynamics (CFD) code to determine the contribution of different species in the ionization process at different engine operating conditions. The CFD code is coupled with DARS-CFD, another module used to allow chemical kinetics calculations. The three-dimensional model accounts for the heterogeneity of the charge and the resulting variations in the combustion products. Furthermore, the model shows the effects of varying fuel injection pressure and engine load on the ion current signal characteristics. Ion current traces obtained experimentally from a heavy duty diesel engine were compared to the 3-D model results. The results of the simulation indicate that some heavy hydrocarbons, soot precursors play a major role, in addition to the role of NOx in ionization in diesel combustion.
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