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[EN] Fuel cell (FC) technologies for mobility are gaining interest as promising options to decarbonize the transport sector in line with the current progress towards the H-2 economy. Previous studies show how the fuel cell range extender (FCREx) powertrain architecture can offer flexible and efficient operation along with the potentially low total cost of ownership (TCO) in passenger car applications. Cradle-to-grave emissions of these vehicles have not been estimated, nor their variation with the components sizing or the H-2 production pathway analyzed. In this study, the life cycle assessment (LCA) and sizing methodologies were combined to address these knowledge gaps. The design spaces were generated by varying the FC maximum power, the battery capacity and the H-2 tank capacity and by simulating the resulting designs with the WLTC 3b driving cycle. Then, the lifetime H-2 and energy consumption results and design parameters were calculated and used as inputs to estimate the greenhouse gases (GHG) and NOX emissions on the manufacturing and fuel production cycles. From the results, it was proven how considering steam methane reforming (SMR) with carbon capture and storage (CCS) as the H-2 production pathway could decrease by 60% and 38% GHG-100 and NOX emissions respectively, with respect to electrolysis where electricity is generated with the EU mix. The optimum design, in terms of emissions, was found to be with low-moderate battery capacity and moderate-high FC maximum power in contrast to the optimum design for performance, which had high battery capacity and high FC stack power., This research has been partially funded by the Spanish Ministry of Science, Innovation and University through the University Fac-ulty Training (FPU) program (FPU19/00550) . Funding for open access charge: CRUE-Universitat Politecnica de Valencia

[EN] Research on combustion systems for Internal Combustion Engines (ICE) is guided by the necessity of improving engine efficiency while achieving the pollutant regulations. In this framework, this study identifies and describes the effect of the bore-to-stroke ratio (B/S) on the combustion system performance and emissions by means of computational fluid dynamics (CFD). The study is applied to a 4-cylinder 4-stroke High Speed Direct Injection (HSDI) CI engine. It is divided in two parts, the first part is focused on one operating point and presents a detailed description of the main effects of different B/S ratios configurations, and the second part compares the results with different engine operating conditions. For both parts the air management, injection settings and compression ratio were kept constant in order to isolate the impact of the B/S ratio. The results confirmed that the indicated thermal efficiency was increased for lower B/S ratio because of the combustion chamber surface area decrease and faster combustion. Regarding the emissions, NOx and soot presented a strong and opposed dependence on B/S ratio generated mostly due to enhanced air¿fuel mixing for lower B/S ratio. Finally, those trends were proven to be independent from the operating condition, giving the study a more general value., Authors acknowledge that this work was possible thanks to the Ayuda para la Formation de Profesorado Universitario (FPU 13/02817) belonging to the Subprogramas de Formacion y de Movilidad del Ministerio de Educacion, Cultura y Deporte from Spain. The authors would also like to recognize the funding and technical support from PSA Groupe

[EN] Aiming to reduce global warming and emissions in general, cleaner technologies are the spotlight of research and industry development. Among them, fuel cell vehicles (FCV) are gaining interest to decarbonize the transport sector. Plug-in FCV or FCV in range-extender configuration (FCREx) is an interesting option to reduce the total cost of ownership (TCO) and the energy usage per km. The aim of this study was to generate design spaces of FCREx by varying the FC stack maximum power output, the battery capacity, and the H-2 tank capacity to understand the implications of this architecture in range, consumption, and cost (estimated with a WLTP driving cycle). Unlike other studies, the approach was focused on a novel architecture for passenger vehicles and was focused on the development of the validated FC system model and the energy management strategy (EMS) optimization for each design, based on the Pontryagin Minimum Principle (PMP). Consumption was found to decrease with increasing battery capacity and FC maximum power due to the higher efficiency of the systems. The design spaces showed how with 5 kg of H-2 and >= 50 kWh of battery capacity the maximum range of FCREx could be over 700 km. The results of this study showed how FCREx architecture could provide overall energy consumption saving up to 6.8% and H-2 consumption saving ranging from 16.8% to 25%, compared to current commercial FCVs. The optimum FCREx design, not only based on performance, should have similar to 30 kWh of battery capacity and >= 80 kW of FC maximum power to minimize manufacturing costs while maximizing efficiency., This research has been partially funded by FEDER, Spain and the Spanish Government through project RTI2018-102025-B-I00 (CLEANFUEL) and through the University Faculty Training (FPU) program

Partially Premixed Combustion (PPC) of fuels in the gasoline octane range has proven to combine low NOX and soot emissions with high indicated efficiencies, while still retaining control over combustion phasing with the injection event. Previous research performed in four-stroke engines, has shown how the operating region where gasoline PPC concept can be successfully implemented is largely linked to the octane number of the fuel, making difficult to cover the entire load range with a fixed fuel. In this framework, 2-stroke engines arise as a promising solution to extend the load range of gasoline PPC concept, since it intrinsically provides equivalent torque response with only half the IMEP required in a 4-stroke cycle. Moreover, 2-stroke architecture provides high flexibility on the air management parameters to substantially control the cylinder conditions and affect the combustion environment, allowing proper combustion control even in low load conditions. An experimental investigation has been performed to evaluate the potential of the PPC concept for pollutant control, using a commercial gasoline with Research Octane Number of 95 in a newly-designed 2-stroke poppet valves automotive diesel engine. The experimental results confirm how it is possible to achieve stable gasoline PPC combustion at a low speed medium load point (1200 rpm, 5 bar IMEP); with good combustion stability (σIMEP below 3%), high combustion efficiency (over 98%), and low NOX and zero soot levels; thanks to the wide control of the cylinder gas temperature provided by the air management settings. Nevertheless, in agreement to the results reported in the literature, the indicated cycle efficiency attained at this low load operating condition is lower than the obtained in conventional diesel combustion conditions. Therefore, a dedicated optimization process of the engine hardware and engine settings is required to fully exploit the benefits of gasoline PPC concept in the investigated 2-stroke engine architecture., The authors of this paper thank the Spanish Ministry of Economy and Competitiveness for the financial support of this research through the Project TRA 2010-20271 (LOWTECOM).