A novel fuzzy logic variable geometry turbocharger and exhaust gas recirculation control scheme for optimizing the performance and emissions of a diesel engine

Variable geometry turbocharger and exhaust gas recirculation valves are widely installed on diesel engines to allow optimized control of intake air mass flow and exhaust gas recirculation ratio. The positions of variable geometry turbocharger vanes and exhaust gas recirculation valve are predominantly regulated by dual-loop proportional–integral–derivative controllers to achieve predefined set-points of intake air pressure and exhaust gas recirculation mass flow. The set-points are determined by extensive mapping of the intake air pressure and exhaust gas recirculation mass flow against various engine speeds and loads concerning engine performance and emissions. However, due to the inherent nonlinearities of diesel engines and the strong interferences between variable geometry turbocharger and exhaust gas recirculation, an extensive map of gains for the P, I, and D terms of the proportional–integral–derivative controllers is required to achieve desired control performance. The present simulation study proposes a novel fuzzy logic control scheme to determine appropriate positions of variable geometry turbocharger vanes and exhaust gas recirculation valve in real-time. Once determined, the actual positions of the vanes and valve are regulated by two local proportional–integral–derivative controllers. The fuzzy logic control rules are derived based on an understanding of the interactions among the variable geometry turbocharger, exhaust gas recirculation, and diesel engine. The results obtained from an experimentally validated one-dimensional transient diesel engine model showed that the proposed fuzzy logic control scheme is capable of efficiently optimizing variable geometry turbocharger and exhaust gas recirculation positions under transient engine operating conditions in real-time. Compared to the baseline proportional–integral–derivative controllers approach, both engine’s efficiency and total turbo efficiency have been improved by the proposed fuzzy logic control scheme while NOx and soot emissions have been significantly reduced by 34% and 82%, respectively

Report by the Aerospace Safety Advisory Panel

The process of preparation for the first two shuttle flights was observed and information from both flights was gathered in order to confirm the concept and performance of the major elements of the space transportation system. To achieve truly operational operating safety, regularity, and minimum practical cost, the organization of efforts between the R&D community and any transportation service organization should be clearly separated with the latter organization assuming responsibilities for marketing its services; planning and acquiring prime hardware and spares; maintainance; certification of procedures; training; and creation of requirements for future development. A technical audit of the application of redundancy concepts to shuttle systems is suggested. The state of the art of space transportation hardware suggests that a number of concept changes may improve reliability, costs, and operational safety. For the remaining R&D flights, it is suggested that a redline audit be made of limits that should not be exceeded for ready to launch

Performance-based health monitoring, diagnostics and prognostics for condition-based maintenance of gas turbines: A review

With the privatization and intense competition that characterize the volatile energy sector, the gas turbine industry currently faces new challenges of increasing operational flexibility, reducing operating costs, improving reliability and availability while mitigating the environmental impact. In this complex, changing sector, the gas turbine community could address a set of these challenges by further development of high fidelity, more accurate and computationally efficient engine health assessment, diagnostic and prognostic systems. Recent studies have shown that engine gas-path performance monitoring still remains the cornerstone for making informed decisions in operation and maintenance of gas turbines. This paper offers a systematic review of recently developed engine performance monitoring, diagnostic and prognostic techniques. The inception of performance monitoring and its evolution over time, techniques used to establish a high-quality dataset using engine model performance adaptation, and effects of computationally intelligent techniques on promoting the implementation of engine fault diagnosis are reviewed. Moreover, recent developments in prognostics techniques designed to enhance the maintenance decision-making scheme and main causes of gas turbine performance deterioration are discussed to facilitate the fault identification module. The article aims to organize, evaluate and identify patterns and trends in the literature as well as recognize research gaps and recommend new research areas in the field of gas turbine performance-based monitoring. The presented insightful concepts provide experts, students or novice researchers and decision-makers working in the area of gas turbine engines with the state of the art for performance-based condition monitoring

Community rotorcraft air transportation benefits and opportunities

Information about rotorcraft that will assist community planners in assessing and planning for the use of rotorcraft transportation in their communities is provided. Information useful to helicopter researchers, manufacturers, and operators concerning helicopter opportunities and benefits is also given. Three primary topics are discussed: the current status and future projections of rotorcraft technology, and the comparison of that technology with other transportation vehicles; the community benefits of promising rotorcraft transportation opportunities; and the integration and interfacing considerations between rotorcraft and other transportation vehicles. Helicopter applications in a number of business and public service fields are examined in various geographical settings

Marine dual fuel engines monitoring in the wild through weakly supervised data analytics

Background: Maritime transportation accounts for around 80% of the world freight movements, remarkably contributing to the global environmental footprint. Dual fuel engines, running on both gaseous and liquid fuels, represent a viable way toward the reduction of emissions at the cost of additional complexity in monitoring activities. Motivation: Data-driven methods represent the frontier in research and in maritime industrial applications, and they usually require a large amount of labelled data, i.e., sensor measurements plus the associated engine status usually annotated by human operators, which are costly and seldomly available in the wild. Unlabelled samples, instead, are commonly, cheaply, and readily available. Hypothesis: The enabling technology for data-driven methods is the availability of a network of sensors and an automation system able to capture and store the associated stream of data. Methods: In this paper, we design and propose multiple alternatives toward the weakly supervised marine dual fuel engines data-driven monitoring. To this aim, we will rely on a Digital Twin of the dual fuel engine or on novelty detection algorithms and we will compare them against state-of-the-art fully supervised approaches. Results: Results on data generated from a real-data validated simulator of a marine dual fuel engine demonstrate that the proposed weakly supervised monitoring approaches lead to a negligible loss in accuracy compared to costly and often unfeasible fully supervised ones supporting the validity of the proposal for its application in the wild. Conclusion: The main outcome is a guideline for selecting the best data-driven dual fuel engine monitoring method according to the available data

Development of an Activity-based Windowing Approach to Evaluate Real-World NOx Emissions from Modern Medium and Heavy-Duty Diesel Trucks

The introduction of in-use emissions regulations by the United States Environmental Protection Agency (U.S.EPA) requires medium-duty (MD) and heavy-duty (HD) engine manufacturers to demonstrate emissions compliance during in-fleet operation. In the United States (U.S.), the Not-to-Exceed (NTE) method is used to evaluate real-world emissions compliance from on-highway MD and HD trucks. Regulatory agencies, engine manufacturers and research entities have identified that the NTE method incorporates numerous exclusions and evaluates emissions compliance only under selective operating conditions that are favorable for the selective catalytic reduction (SCR) system to reduce oxides of nitrogen (NOx) emissions efficiently. Such operation is typically encountered only by vocations that experience sustained highway driving operation, which is not entirely representative of actual highly diverse real-world operation experienced by the engine/aftertreatment system. Evaluation of real-world driving emissions (RDE) plays a critical role in monitoring and ensuring the performance of emissions control systems. Portable emissions measurement system (PEMS) serves as a robust tool to assess emissions levels during real-world operation. However, utilization of PEMS for large-scale deployment is time-consuming, labor-intensive, and expensive. As a vision of potential elements for a next-tier of in-use NOx monitoring systems, there is an actively growing research and regulatory interest to evaluate the feasibility of using existing on-boardNOx sensors for HD on-board NOx compliance. However, research studies have highlighted that NOx sensor measurements are also subjected to cross-sensitivity from other species in the exhaust stream. The global objective of the study was to develop an alternative approach that attempts to bridge the gap between current in-use certification procedures and highly diverse real-world operation for evaluation of in-use NOx emissions. The study outlines a vehicle activity-based windowing (ABW) approach that provides an event-based bifurcation of the engine and aftertreatment operational conditions. The thermal boundary bin exhibits bin boundary conditions favorable for SCR catalytic activity. Results of the study show that the 90th percentile of ABW bin-1a bsNOx emissions (i.e., on average of the individual vehicle datasets) was below the current NTE NOx limit. In terms of data usage, the ABW approach provides a unique opportunity of utilizing ~95% and 83% (Phase-1 and Phase-2) of test activity acquired from valid ABW trips. In comparison, the current NTE approach evaluated over a diverse in-use test activity collected as part of the HDIUT program exhibits utilization of only a sparse amount (i.e., less than 10%) of in-use test activity for emissions compliance evaluation. In light of using existing on-board NOx sensors for the screening of in-fleet activity, the study evaluates measurement thresholds of NOx sensors under real-world operating conditions. In the absence of a substantial amount of ammonia (NH3), it was observed that the average measurement deviation was within ±10% for NOx concentration levels between 10 ppm and 200 ppm. However, statistical principal component analysis (PCA) indicates a hypothetic relation between NOx sensor measurements and rapid changes in water (H2O) concentrations

Improving Russia's policy on foreign direct investment

Foreign direct investment brings host countries capital, productive facilities, and technology transfers as well as employment, new job skills, and management expertise. It is important to the Russian Federation, where incentives for competition are limited and incentives to becoming efficient are blunted by interregional barriers to trade, weak creditor rights, and administrative barriers to new entrants. The authors ague that the old policy paradigm of foreign direct investment (established before World War II and prevalent in the 1950s and 1960s) still governs Russia. In this paradigm there are only two reasons for foreign direct investment: access to inputs for production and access to markets for outputs. Such kinds of foreign direct investment, although beneficial, are often based on generating exports that exploit cheap labor or natural resources, or are aimed at penetrating protected local markets, not necessarily at world standards for price and quality. They contend that Russia should phase out high tariffs and non-tariff protection for the domestic market, most tax preferences for foreign investors (which don't increase foreign direct investment but do reduce fiscal revenues), and many restrictions on foreign investment. They recommend that Russia switch to a modern approach to foreign direct investment by: 1) Amending the newly enacted foreign direct investment law so that it will grant non-discriminatory"national treatment"to foreign investors for both right of establishment, and post-establishment operations, abolish conditions (such as local content restrictions) inconsistent with the World Trade Organization agreement on trade-related investment measures (TRIMs), and make investor-state dispute resolution mechanisms more efficient (giving foreign investors the chance to seek neutral binding international arbitration, for example). 2) Strengthening enforcement of property rights. 3) Simplifying registration procedures for foreign investors, to make them transparent and rules-based. 4) Extending guarantee schemes covering basic non-commercial risks.Environmental Economics&Policies,Labor Policies,International Terrorism&Counterterrorism,Economic Theory&Research,Payment Systems&Infrastructure,Environmental Economics&Policies,Foreign Direct Investment,Economic Theory&Research,National Governance,International Terrorism&Counterterrorism