21 research outputs found
Toward Green Vehicles Digitalization for the Next Generation of Connected and Electrified Transport Systems
This survey paper reviews recent trends in green vehicle electrification and digitalization, as part of a special section on “Energy Storage Systems and Power Conversion Electronics for E-Transportation and Smart Grid”, led by the authors. First, the energy demand and emissions of electric vehicles (EVs) are reviewed, including the analysis of the trends of battery technology and of the recharging issues considering the characteristics of the power grid. Solutions to integrate EV electricity demand in power grids are also proposed. Integrated electric/electronic (E/E) architectures for hybrid EVs (HEVs) and full EVs are discussed, detailing innovations emerging for all components (power converters, electric machines, batteries, and battery-management-systems). 48 V HEVs are emerging as the most promising solution for the short-term electrification of current vehicles based on internal combustion engines. The increased digitalization and connectivity of electrified cars is posing cyber-security issues that are discussed in detail, together with some countermeasures to mitigate them, thus tracing the path for future on-board computing and control platforms.publishedVersio
Battery Aging-Aware Online Optimal Control: An Energy Management System for Hybrid Electric Vehicles Supported by a Bio-Inspired Velocity Prediction
In this manuscript, we address the problem of online optimal control for torque splitting in hybrid electric vehicles that minimises fuel consumption and preserves battery life. We divide the problem into the prediction of the future velocity profile (i.e. driver intention estimation) and the online optimal control of the hybrid powertrain following a Model Predictive Control (MPC) scheme. The velocity prediction is based on a bio-inspired driver model, which is compared on various datasets with two alternative prediction algorithms adopted in the literature. The online optimal control problem addresses both the fuel consumption and the preservation of the battery life using an equivalent cost given the estimated speed profile (i.e. guaranteeing the desired performance). The battery degradation is evaluated by means of a state-of-the-art electrochemical model. Both the predictor and the Energy Management System (EMS) are evaluated in simulation using real driving data divided into 30 driving cycles from 10 drivers characterised by different driving styles. A comparison of the EMS performances is carried out on two different benchmarks based on an offline optimization, in one case on the entire dataset length and in the second on an ideal prediction using two different receding horizon lengths. The proposed online system, composed of the velocity prediction algorithm and the optimal control MPC scheme, shows comparable performances with the previous ideal benchmarks in terms of fuel consumption and battery life preservation. The simulations show that the online approach is able to significantly reduce the capacity loss of the battery, while preserving the fuel saving performances
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The Psychology of Vehicle Performance: Implications for the Uptake of Electric Vehicles
Road transport accounts for around 16% of global CO2 emissions, and electric vehicles (EVs) represent a potential mitigation route. High performance might offset the disadvantages of higher cost and short range that make their uptake problematic. This research investigated how consumer drivers construe, perceive and value vehicle performance. Research with UK drivers, using the repertory grid method, found that drivers construe vehicle performance as having two independent dimensions, dynamic and cruising performance. A new inter-goal dynamics and feedback control model of driving behaviour was developed to account for differences in the opportunities afforded to perceive vehicle performance in naturalistic driving. This was embedded in a Bayesian model for perception of available vehicle performance. Driving simulation and test track experiments with UK drivers found that: driving behaviour was strongly affected by goal activation; drivers could perceive performance differences in naturalistic driving, but only if they were large; the lowest perceptual difference threshold, for mid-range available vehicle acceleration, was 7.7%; smaller differences could affect driving behaviour (overtaking) through a process of implicit learning. The symbolic value of products is conferred by their symbolic meanings. Two new methods were developed to quantify symbolic meanings, grounded in costly signalling theory, which represents them in terms of personality traits of a typical user. The symbolic meanings of car types, performance attributes and driving styles were all measured. In a randomised controlled trial, UK consumer drivers rated an EV better on dynamic and cruising performance than a conventional ICE control, but this benefit was insufficient to outweigh the disadvantages. The symbolic meaning of an EV was found to be consistent with cruising performance, but inconsistent with dynamic performance. Extended-range EVs would have the dynamic and cruising performance benefits of EVs without the range disadvantages, and may be a desirable option for many once costs reduce
Energy Management
Forecasts point to a huge increase in energy demand over the next 25 years, with a direct and immediate impact on the exhaustion of fossil fuels, the increase in pollution levels and the global warming that will have significant consequences for all sectors of society. Irrespective of the likelihood of these predictions or what researchers in different scientific disciplines may believe or publicly say about how critical the energy situation may be on a world level, it is without doubt one of the great debates that has stirred up public interest in modern times. We should probably already be thinking about the design of a worldwide strategic plan for energy management across the planet. It would include measures to raise awareness, educate the different actors involved, develop policies, provide resources, prioritise actions and establish contingency plans. This process is complex and depends on political, social, economic and technological factors that are hard to take into account simultaneously. Then, before such a plan is formulated, studies such as those described in this book can serve to illustrate what Information and Communication Technologies have to offer in this sphere and, with luck, to create a reference to encourage investigators in the pursuit of new and better solutions
Design of battery pack and internal combustion engine thermal models for hybrid electric vehicles
This thesis focuses on the design of computational models, capable of simulating the thermal behaviour of a battery pack and internal combustion engine equipping a hybrid electric vehicle tested over a given driving cycle. Both the models manage a lot of input variables and take into account all the thermophysical aspects regulating the heat exchange phenomena between the battery and engine devices and the cooling medium used to maintain their thermal control. The main objective of the research is to design the two models and integrate them in the simulation tool used by Chrysler to predict the performance of hybrid vehicles in the early design stages. After that, using the battery cooling system model, a sensitivity study is performed to understand which are the most important factor affecting the thermal behaviour of the battery cells. Finally, a validation phase is conducted for both the software to guarantee the validity of their results
Strategic Options for Azure Dynamics in Hybrid and Battery Electric Vehicle Markets
Azure Dynamics provides electric vehicle powertrain technology to commercial truck fleets in North America and Europe. Azure Dynamics is a firm in distress and fighting for survival, having filed for bankruptcy protection in March 2012. An analysis of commercial trucking markets reviews factors driving vehicle electrification and provides a market segmentation to find segments best suited to Azure’s technology. Porter’s Five Forces methodology is used to assess target market attractiveness and to identify key success factors. An internal analysis of Azure employs a value chain and a VRIO model to identify core competencies. A strategic fit matches firm capabilities to the Differentiation Focus generic strategy. A performance assessment maps Azure’s competitive position within light-duty and medium-duty truck market segments. Strategic options emerge from this analysis and are evaluated using a Balanced Scorecard. From the analysis, the strategic option of selling Azure as a going concern is recommended. Ideally, the acquirer would be a firm with deep financial resources and a long-term vision. This option provides Azure with enough working capital to let it deal with product gross margin issues, and to eliminate use of equity financing to fund operating costs
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Environmental stimuli shape adaptive immunity by enhancing T helper cell differentiation and the germinal centre response
Immune cells have evolved to respond to external danger signals and to incorporate information about environmental cues to adapt their differentiation and effector function. Because of this, it is important that immune cells are studied in the context of their surroundings. In this thesis, I investigated the roles of environmental endoplasmic reticulum (ER) stress, the gut microbiome and ageing on adaptive immunity. Immune cells have been shown to integrate inflammatory signalling with the ER stress response pathway. This response is triggered by a variety of environmental stresses such as low nutrient availability, hypoxia and mechanical stress. I found that the ER stress response acts as a potent driver of T helper 17 (Th17) cell differentiation resulting in Th17 cells with a pathogenic gene expression signature. This suggests a link between ER stress-inducing conditions such as low nutrient availability, and the pathology of Th17 cell-mediated autoimmune diseases. Another physiological scenario in which the immune microenvironment changes is during ageing. Ageing-related changes of the gut microbiome have recently been linked to increased frailty and systemic inflammation. This change in microbial composition with age occurs in parallel with a decline in function of the gut immune system, however it is not clear if there is a causal link between the two. Here, I establish that the defective germinal centre (GC) reaction in Peyer’s patches in the small intestine of aged mice can be rescued by co-housing of adult and aged mice, and via faecal transfers from adult into aged mice. This demonstrates that the poor GC reaction in aged animals is not irreversible, and that it is possible to improve immune responses in older individuals by replenishing the gut microbiome. To determine whether GC responses can also be improved in peripheral lymph nodes, we investigated the role of defective helper T cell priming in aged mice. We observed that the age-associated defect in the GC reaction is partly due to impaired T cell priming by dendritic cells (DCs). By boosting type I interferon signalling in DCs at the time of immunisation, I was able to improve T cell priming and GC formation in aged mice. This demonstrates that not only the gut microbiome, but also DCs are exciting targets to improve GC responses in ageing and highlights the importance of environmental stimuli in shaping adaptive immunity.PhD funding was provided by the EU-funded Horizon 2020 ENLIGHT-TEN project No. 675395 and additional consumables funding was provided by Marc Veldhoen and Michelle Linterman