Real Automotive Application Research Articles

Investigation of multiple commercial electrocatalysts and electrocatalyst degradation for fuel cells in real vehicles.

Proton exchange membrane fuel cells (PEMFCs) are regarded as one of the promising new carbon mitigation strategies to realize carbon neutrality. However, efficient and robust electrocatalysts are vital for the commercialization of PEMFCs. Herein, three commercial Pt/C electrocatalysts were investigated including a carbon support and Pt nanoparticles (NPs) to identify their merits and disadvantages, which will help end users quickly select catalysts with excellent performances among the many brands of domestic and foreign catalysts to further better study and better utilize them. Subsequently, they were optimized for real automotive application for about 1800 h, and then the variations in the electrocatalysts on the MEA were analysed by transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The mean Pt particle size of the catalysts after operating for 1800 h (cathode, 9.9 ± 3.2 nm) was nearly 4-fold that before use (2.5 ± 0.6 nm), greatly reducing the exposure of metal sites, which was due to the violent three-phase interfacial reaction (ORR) occurring at the cathode side. Also, this assertion was supported by the negative shift in the Pt 4f peaks in the XPS spectra. Moreover, to determine the coalescent evolution of the Pt particles, an in situ TEM experiment was performed. This allowed us to perform fundamental Pt NP degradation studies on the carbon support, which can result in an improvement in the sustainability of catalysis.

A Fast Switching Current Controlled DC/DC Converter for Automotive Applications

Automotive industry requires integrated circuits with both low cost, to maintain product competitiveness, and high efficiency, moving towards solutions as green as possible. Each electronic device within the car needs for a regulator to provide a steady supply to ensure correct and safe operation. Among all regulator, DC/DC Converters are the most valid solution to achieve a high efficiency-price ratio. The DC/DC Converter needs for a control loop to monitor the load operation. The basic control loop topologies are well known in the state-of-the-art. The paper presents a DC/DC Buck Converter for automotive applications designed in low cost technology with an upgraded version of the Peak Current Mode Control which uses a constant off-time. For chip area reduction, an n-channel power-DMOS is chosen as power transistor. The design of each block composing the circuit is presented. To guarantee DC-DC Buck converters high-efficiency and low cost (in terms of external components) increasing switching frequency is mandatory. A  1.5 MHz switching frequency has been chosen to reduce external components size. The device is optimized by design to be able to achieve 94.4% efficiency using a 3V  3A load. The post-layout simulations of the system are shown, confirming the expected circuit behavior also including the presence of wiring parasites. A PCB is also designed to test the packaged die to ultimately demonstrate the chip’s robustness and suitability in a real automotive application.

An Extensive Soft Error Reliability Analysis of a Real Autonomous Vehicle Software Stack

Automotive systems are integrating artificial intelligence and complex software stacks aiming to interpret the real world, make decisions, and perform actions without human input. The occurrence of soft errors in such systems can lead to wrong decisions, which might ultimately incur in life losses. This brief focuses on the soft error susceptibility assessment of a real automotive application running on top of unmodified Linux kernels, and considering two commercially available processors, and three cross-compilers. Results collected from more than 29 thousand simulation hours show that the occurrence of faults in critical functions may cause 2.16× more failures on the system.

Perovskite-Based Catalysts as Efficient, Durable, and Economical NOx Storage and Reduction Systems

Diesel engines operate under net oxidizing environment favoring lower fuel consumption and CO2 emissions than stoichiometric gasoline engines. However, NOx reduction and soot removal is still a technological challenge under such oxygen-rich conditions. Currently, NOx storage and reduction (NSR), also known as lean NOx trap (LNT), selective catalytic reduction (SCR), and hybrid NSR–SCR technologies are considered the most efficient control after treatment systems to remove NOx emission in diesel engines. However, NSR formulation requires high platinum group metals (PGMs) loads to achieve high NOx removal efficiency. This requisite increases the cost and reduces the hydrothermal stability of the catalyst. Recently, perovskites-type oxides (ABO3) have gained special attention as an efficient, economical, and thermally more stable alternative to PGM-based formulations in heterogeneous catalysis. Herein, this paper overviews the potential of perovskite-based formulations to reduce NOx from diesel engine exhaust gases throughout single-NSR and combined NSR–SCR technologies. In detail, the effect of the synthesis method and chemical composition over NO-to-NO2 conversion, NOx storage capacity, and NOx reduction efficiency is addressed. Furthermore, the NOx removal efficiency of optimal developed formulations is compared with respect to the current NSR model catalyst (1–1.5 wt % Pt–10–15 wt % BaO/Al2O3) in the absence and presence of SO2 and H2O in the feed stream, as occurs in the real automotive application. Main conclusions are finally summarized and future challenges highlighted.

Improved Holistic Analysis for Fork–Join Distributed Real-Time Tasks Supported by the FTT-SE Protocol

Modern distributed real-time embedded applications have high processing requirements associated with strict deadlines. For some applications, such constraints cannot be fulfilled by existing single-core embedded platforms. A solution is to parallelize the execution of the applications, by allowing networked nodes to distribute their workload to remote nodes with spare capacity. In that context, this paper presents a holistic timing analysis for fixed-priority fork–join parallel/distributed tasks. Furthermore, we extend the holistic approach to consider the interaction between parallel threads and messages interchanged through a flexible time triggered switched Ethernet network, and we show how the pessimism on the worst case response time computation of such tasks can be reduced by considering the pipeline effect that occurs in such distributed systems. To evaluate the performance and correctness of the holistic model, this paper includes a numerical evaluation based on a real automotive application. The obtained results show that the proposed method is effective in distributing the load by different nodes, allowing a significant reduction of the worst case response time of the tasks. Moreover, the paper also reports an implementation of the model on a Linux library, called parallel/distributed real-time, as well as the corresponding results obtained on a real testbed. The obtained results are in accordance with the predictions of the holistic timing analysis.

A kinetic model of the hydrogen assisted selective catalytic reduction of NO with ammonia over Ag/Al2O3

A global kinetic model which describes H2‐assisted NH3‐SCR over an Ag/Al2O3 monolith catalyst has been developed. The intention is that the model can be applied for dosing NH3 and H2 to an Ag/Al2O3 catalyst in a real automotive application as well as contribute to an increased understanding of the reaction mechanism for NH3‐SCR. Therefore, the model needs to be simple and accurately predict the conversion of NOx. The reduction of NO is described by a global reaction, with a molar stoichiometry between NO, NH3 and H2 of 1:1:2. Further reactions included in the model are the oxidation of NH3 to N2 and NO, oxidation of H2, and the adsorption and desorption of NH3. The model was fitted to the results of an NH3‐TPD experiment, an NH3 oxidation experiment, and a series of H2‐assisted NH3‐SCR steady‐state experiments. The model predicts the conversion of NOx well even during transient experiments. © 2013 American Institute of Chemical Engineers AIChE J, 59: 4325–4333, 2013