Honda Insight | EPFL Graph Search

La Honda Insight est une automobile hybride électrique développée par le constructeur japonais Honda. La première génération fut produite de 1999 à 2006 sous la forme d'une compacte trois portes, ce fut la première voiture hybride produite par Honda. La seconde génération de l'Insight fut introduite au Japon en , et dans les autres nations courant 2009. La nouvelle Insight fut lancée aux États-Unis le . Elle a été la voiture la plus vendue au Japon en , et la première voiture hybride à atteindre cette place. Première génération (1999 - 2006) Historique Basée sur le concept car Honda J-VX présenté au Tokyo Motor Show en 1997, l'Insight est introduite en . Elle représente la première voiture hybride à avoir été commercialisée en Amérique du Nord. La voiture était totalement pensée pour minimiser la consommation ainsi que les émissions de gaz à effet de serre, grâce notamment à une aérodynamique soignée et une structure en aluminium allégée. Design

Emission reduction by targeted transient operations in three-way catalysts for heavy-duty natural gas applications

Moyu Wang

To curb the severe effects of climate change, our society needs to radically reduce its CO2 footprint. For the heavy-duty sector, where electrification is difficult, alternative fuels can be the solution. Methane-fueled engines have lower energy-specific CO2 emissions than conventional Diesel-fueled engines. Furthermore, they have the potential of becoming carbon-neutral, when combined with bio-methane/synthetic methane. However, oxidation of unburnt methane in the exhaust gas poses a challenge for aftertreatment systems. The aim of this thesis is to investigate the mechanism of methane abatement and to reveal methods to reduce methane and other hazardous gas emissions. The majority of the experiments were conducted directly on an engine test bench, which is rarely seen in studies focusing on catalytic reaction pathways. Initial investigations focused on methane abatement under steady state and Î»-step transitions. Under steady state, the presence of oxygen was identified as a prerequisite for methane conversion. Reacting with oxygen is the only methane conversion pathway. However, after step transition from oxygen excess conditions (slightly lean) to oxygen-poor conditions (slightly rich), high methane conversion was observed under rich conditions with no oxygen available. This high conversion was attributed to steam reforming (SR), which was activated by the step transition. The SR reaction rate decreased over time when staying at rich conditions, until full deactivation. Investigations in the lab-scale model gas reactor confirmed this analysis. In addition, the reason for SR deactivation was identified by DRIFTS measurements as the accumulation of carbonates on the catalytic surface, blocking the active sites. Based on the identified importance of the SR reaction, targeted Î» oscillations across stoichiometry were introduced, in order to repeatably activate SR and achieve sustainable high methane conversion. During the rich parts of the oscillations, methane was converted via SR, while, during lean parts, the carbonates were periodically removed from the catalyst surface. With these oscillations, methane conversion has been significantly improved, in comparison to steady state. In parallel, a numerical model has been developed in order to simulate the catalyst behavior under oscillating conditions. The model provided insights on the reaction pathways and their distribution along the catalyst axis. The catalytic activity of the different Platinum-group metals has been investigated for the identified reactions. Various catalysts of different compositions were tested under cold start, Î» oscillations and quasi-steady state conditions. Both Pt and Pd activated SR reactions, however SR attenuation was faster in Pt catalysts. In lean conditions, Pt exhibited higher methane oxidation. Rh was identified as important for enhancing NOx reduction and lowering NH3 emissions. The combination of all three metals has improved the overall catalyst performances. In the final part of the thesis, a special aftertreatment system was investigated. It combines a Pd/Rh catalyst subject to stoichiometric conditions with a Pt oxidation catalyst subject to lean conditions. In the Pd/Rh catalyst, methane was removed via Î» oscillations. In the Pt catalyst, the remaining CO, H2 and NH3 were oxidized. The setup provided a novel perspective in reducing the overall environmental impacts.

EPFL2022

Hydrogen storage and electrochemical properties of LaNi5-xCux hydride-forming alloys

Natalia Gasilova, Mariana Spodaryk, Andreas Züttel

LaNi5-type alloys are commercial materials for the negative electrode in Ni-MH rechargeable batteries. Partial substitution of La by mischmetal (Mm) and of Ni by elements like Co, Al, and Mn significantly improve the cycle stability and high-rate discharge capacity of the electrodes. The partial substitution of Ni by Cu was studied previously for several selected ternary alloys with a special focus on crystal structure change upon substitution and gas phase hydrogen absorption. We present in this paper the results of the study of the electrochemical activation, discharge kinetics, equilibrium charge/discharge, and cycle life of electrodes made from four different LaNi5-xCux (x = 0.1, 0.5, 0.9, 1) alloys in order to provide full insights into utilization of these alloys. (C) 2018 Elsevier B.V. All rights reserved.

ELSEVIER SCIENCE SA2019

Thermodynamics and kinetics of protonated merocyanine photoacids in water

Cesare Berton, Daniel Maria Busiello, Farzaneh Fadaei Tirani, Cristian Pezzato, Rosario Scopelliti, Kay Severin, Euro Solari, Stefano Zamuner

Metastable-state photoacids (mPAHs) are chemical species whose photo-activated state is long-lived enough to allow for proton diffusion. Liao's photoacid (1) represents the archetype of mPAHs, and is being widely used on account of its unique capability to change the acidity of aqueous solutions reversibly. The behavior of 1 in water, however, still remains poorly understood. Herein, we provide in-depth insights on the thermodynamics and kinetics of 1 in water through a series of comparative 1H NMR and UV-Vis studies and relative modelling. Under dark conditions, we quantified a three-component equilibrium system where the dissociation (Ka) of the open protonated form (MCH) is followed by isomerization (Kc) of the open deprotonated form (MC) to the closed spiropyran form (SP) – i.e., in the absence of light, the ground state acidity can be expressed as KGSa = Ka(1 + Kc). On the other hand, under powerful and continuous light irradiation we were able to assess, for the first time experimentally, the dissociation constant (KMSa) of the protonated metastable state (cis-MCH). In addition, we found that thermal ring-opening of SP is always rate-determining regardless of pH, whereas hydrolysis is reminiscent of what is found for Schiff bases. The proposed methodology is general, and it was applied to two other compounds bearing a shorter (ethyl, 2) and a longer (butyl, 3) alkyl-1-sulfonate bridge. We found that the pKa remains constant, whereas both pKc and pKMSa linearly increase with the length of the alkyl bridge. Importantly, all results are consistent with a four-component model cycle, which describes perfectly the full dynamics of proton release/uptake of 1–3 in water. The superior hydrolytic stability and water solubility of compound 3, together with its relatively high pKGSa (low Kc), allowed us to achieve fully reversible jumps of 2.5 pH units over 18 consecutive cycles (6 hours).