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As vibration and noise regulations become more stringent, numerical models need to incorporate more detailed damping treatments. Commercial frameworks, such as Nastran and Actran, allow the representation of trim components as frequency-dependent reduced impedance matrices (RIM) in frequency response analysis of fully trimmed models. The RIM is versatile enough to couple the trims to modal-based or physical components. If physical, the trim components are reduced on the physical coupling degrees of freedom (DOFs) for each connected interface. If modal, the RIMs are projected on the eigenmodes of the connected component. While a model size reduction is achieved compared to the original model, most numerical models possess an extensive number of interfaces DOFs, either modal or physical, leading to large dense RIM which triggers substantial memory and disk storage.

Fossil fuels such as natural gas used in engines still play the most important role worldwide despite such measures as the German energy transition which however is also exacerbating climate change as a result of carbon dioxide emissions. One way of reducing carbon dioxide emissions is the choice of energy sources and with it a more favourable chemical composition. Natural gas, for instance, which consist mainly of methane, has the highest hydrogen to carbon ratio of all hydrocarbons, which means that carbon dioxide emissions can be reduced by up to 35% when replacing diesel with natural gas. Although natural gas engines show an overall low CO2 and pollutant emissions level, methane slip due to incomplete combustion occurs, causing methane emissions with a more than 20 higher global warming potential than CO2.

In response to global climate change, there is a widespread push to reduce carbon emissions in the transportation sector. For the difficult to decarbonize heavy-duty (HD) vehicle sector, lower carbon intensity fuels can offer a low-cost, near-term solution for CO2 reduction. The use of natural gas can provide such an alternative for HD vehicles while the increasing availability of renewable natural gas affords the opportunity for much deeper reductions in net-CO2 emissions. With this in consideration, the US National Renewable Energy Laboratory launched the Natural Gas Vehicle Research and Development Project to stimulate advancements in technology and availability of natural gas vehicles. As part of this program, Southwest Research Institute developed a hybrid-electric medium-HD vehicle (class 6) to demonstrate a substantial CO2 reduction over the baseline diesel vehicle and ultra-low NOx emissions.

Water management in PEMFC power generation systems is a key point to guarantee optimal performances and durability. It is known that a poor water management has a direct impact on PEMFC voltage, both in drying and flooding conditions: furthermore, water management entails phenomena from micro-scale, i.e., formation and water transport within membrane, to meso-scale, i.e., water capillary transport inside the GDL, up to the macro-scale, i.e., water droplet formation and removal from the GFC. Water transport mechanisms through the membrane are well known in literature, but typically a high computational burden is requested for their proper simulation. To deal with this issue, the authors have developed an analytical model for the water membrane content simulation as function of stack temperature and current density, for fast on-board monitoring and control purposes, with good fit with literature data.

Contact a member of the 2024 SAE On-Board Diagnostics Symposium-Europe sales team about exhibiting or sponsoring.

September 17-19, 2019 │ Garden Grove, CA, USA

September 17-19, 2019 │ Garden Grove, CA, USA

When you exhibit or sponsor at the On-Board Diagnostics Symposium-Europe (OBD-EU) it is your greatest chance to get in front of the industry’s preeminent decision makers in 2022.

Powertrains, Fuels & Lubricants Conference & Exhibition

Contact a member of the 2024 SAE On-Board Diagnostics Symposium-Europe team for any questions regarding the event.

September 17-19, 2019 │ Garden Grove, CA, USA

PF&L is priority event for mobility professionals that specialize in powertrain, fuels, lubricants technology, including OEM and Tier 1 component suppliers Light medium and heavy-duty vehicle system and product design engineers

Attend the 2021 Innovations in Mobility Automotive Digital Summit — brought to you by SAE International® — is designed to bring together mobility organizations from across the industry in a neutral forum to accelerate their business and build future partnerships.

PF&L is priority event for mobility professionals that specialize in powertrain, fuels, lubricants technology, including OEM and Tier 1 component suppliers Light medium and heavy-duty vehicle system and product design engineers.