Transient performance of turbocharged vehicle diesel engines

Imperial Users onl

Development of a test facility ot upgrade a con-ventional exhaust gas emission analyser used for transient measurement

38 p.This report summarizes the developmental works of upgrading a slow response conventional exhaust gas emission analyser used for dynamic measurement. The project is funded by Applied Research Board, Nanyang Technological University with reference number ARP 32/92. It is well known that conventional gases emission analyzers based upon non-dispersive infra-red (NDIR) measuring technique are of limited use in transient engine testing due to the dynamic of these analyzers cause distortion of emission signal measured during transient engine operation. A combined experimental and phenomenological modelling approach is proposed which simulates the behaviour of the gas transport through an emission analyzer by a series of alternately arranged pipes and surge volumes such that the distortion of the emission signal can be physically explained and modelled.RP 32/92

Development of a measuring technique for real time particulate emissions from internal combustion engines

This report presents the work on the development of a new technique capable of measuring the particulate matter in real-time.RG 13/9

Innovative control of ultra-low toxic emissions in the exhaust of internal combustion engines

This report presents the work on the development of a new technique capable of controlling the cold-start emissions, in particular the carbon monoxide (CO), unburned hydrocarbon (uHC) and oxides of (NOx), of an electronic fuel-injection (EFI)gasoline engine fitted with a three-way catalytic converter.RG 62/9

Understanding the role of cathode structure and property on water management and electrochemical performance of a PEM fuel cell

Water management is vital for the successful development of PEM fuel cells. Water should be carefully balanced within a PEM fuel cell to meet the conflicting requirements of membrane hydration and cathode anti-flooding. In order to understand the key factors that can improve water management and fuel cell performance, the cathodes with different structures and properties are prepared and tested in this study. The experimental results show that even though no micro-porous layer (MPL) is placed between the cathode catalyst layer (CCL) and macro-porous substrate (MaPS), a hydrophobic CCL is effective to prevent cathode flooding and keep membrane hydrated. The impedance study and the analysis of the polarization curves indicate that the optimized hydrophobic micro-porous structure in the MPL or the hydrophobic CCL could be mainly responsible for the improved water management in PEM fuel cells, which functions as a watershed to provide wicking of liquid water to the MaPS and increase the membrane hydration by enhancing the back-diffusion of water from the cathode side to the anode side through the membrane

The profitability estimation of a 100 MW power-to-gas plant

Power-to-Gas (PtG) is a grid-scale energy storage technology that converts electricity into the gas fuel as an energy carrier. Specifically, it utilizes surplus renewable electricity to generate hydrogen from electrolysis with Solid Oxide Cell (SOC), and the hydrogen is then combined with CO2 through Sabatier process to form methane. The methane can be transported within existing natural gas pipeline or city gas pipeline for civil and commercial usages. To increase the utilization rate of the plant, it is sensible to make use of the reverse function of SOC, which is a Solid Oxide Fuel Cell (SOFC), to generate electricity when the grid is short of power. The energy input of this process is methane, and it is called Gas-to-Power (GtP). This study estimated the realistic cost of building a 100 MW PtG plant. The focus of this study is given to the effect of several parameters on the Levelized Cost of Electricity (LCOE) of the PtG plant.Published versio

Micromachined polymer electrolyte membrane and direct methanol fuel cells : a review

This review reports recent progress of the development of micromachined membrane-based fuel cells. The review first discusses the scaling law applied to this type of fuel cells. Impacts of miniaturization on the performance of membrane-based fuel cells are highlighted. This review includes only the two most common micro fuel cell types: proton exchange membrane micro fuel cells (PEMμFC) and direct methanol micro fuel cell (DMμFC). Furthermore, we only consider fuel cells with active area of a single cell less then one square inch. Since the working principles of these fuel cell types are well known, the review only focuses on the choice of material and the design consideration of the components in the miniature fuel cell. Next, we compare and discuss the performance of different micro fuel cells published recently in the literature. Finally, the review gives an outlook on possible future development of micro fuel cell research.Accepted versio

ZIF-8 derived CeO₂-Fe₃O₄@Fe-N/C catalyst for oxygen reduction reaction

Looking for non-noble metal catalysts with low cost, high activity, and high stability to replace platinum in oxygen reduction reaction (ORR) has aroused great concern. According to previous studies, Fe-Nx/C material is one of the most promising non-noble metal catalysts for ORR. In this study, new Fe-Nx/C material was synthesized by introducing CeO2 and Fe3O4 nanoparticles into a Fe-Nx/C material derived from ZIF-8 as precursors. The new material was called CeO2-Fe3O4@Fe-N/C catalyst and the activity of the catalyst was found to be significantly improved in 0.1 mol L−1 KOH. The half-wave potential of CeO2-Fe3O4@Fe-N/C (0.892 V) is higher than that of Pt/C by 67 mV. In the stability test, the half-wave potential of CeO2-Fe3O4@Fe-N/C was only reduced by 4 mV after 5,000 cycles. The high performance is attributed to the introduction of CeO2 and Fe3O4, which gives CeO2-Fe3O4@Fe-N/C enhanced electrocatalytic activity and long-term stability. This approach makes CeO2-Fe3O4@Fe-N/C a promising candidate for cathode catalysts in renewable energy conversion devices.The project was financially supported by a research grant (204-A018001) from the China-Singapore International Joint Research Institute

Performance Evaluation and Degradation Mechanism for Proton Exchange Membrane Fuel Cell with Dual Exhaust Gas Recirculation

Fuel gas utilization and water management are particularly challenging integrated engineering problems in hydrogen–oxygen proton exchange membrane fuel cell (H2/O2 PEMFC) systems. Herein, a standardized process is adopted to evaluate the performance and investigate the degradation mechanisms of a PEMFC with dual exhaust gas recirculation. The purpose of incorporating recirculation subsystems in the fuel cell is to achieve a high fuel gas utilization rate and realize effective water management inside the stack, which consists of 3D‐printed ejectors and a customized recirculation pump. Evaluation of the electrochemical performance degradation and morphological characterization of the fuel cells under different operating strategies are performed after 50 h durability experiments. At a current density of 400 mA cm−2, the performance degradation rates of the stack decrease from 16.50% to 7.49% and 0.71% in the ejector and recirculation pump operation strategies, respectively. The results show that using exhaust gas recirculation devices (ejector/pump) in the fuel cell stack can help in effectively mitigating water flooding and chemical degradation of the membrane electrode assembly. The findings of the study provide a perspective on the exhaust gas recirculation behavior and contribute to the engineering application of H2/O2 PEMFCs

Long-distance renewable hydrogen transmission via cables and pipelines

Intermittency is one of the main obstacles that inhibit the wide adoption of the renewable energy in the power sector. Small-scale fluctuations can be tackled by short-term energy storage system, whereas long-term or seasonal intermittencies rely on large-scale energy management solutions. Besides the supply and demand mismatch in temporal domain, renewable energy sources are usually far away from consumption points. To connect the energy sources to the demand cost-effectively, cable transmission is usually the default option, and considering the long distance, other emerging energy carriers such as hydrogen could be a feasible option. However, there is handful studies on the quantitative evaluation of the long-distance energy transmission cost. This paper investigated the economic feasibility of renewable energy transmission via routes of power cable and gas pipeline. In the direct power transmission case, renewable energy is transmitted via HVDC cable and then converted to hydrogen for convenient storage. The alternative case converts renewable energy into hydrogen at the source and transports the hydrogen in the gas pipeline to consumers. Existing data available from public domain are used for cost estimation. Results show that the improvements of capacity factor and transmission scale are the most cost-effective approach to make the renewable hydrogen economically viable. At 4000 km of transmission distance, renewable hydrogen LCOE of 7 US$/kg and 9 US$/kg are achievable for the corresponding optimum cases, respectively