Search results for "Engines"

A Study on the Use of Combustion Phase Indicators for MBT Spark Timing on a Bi-Fuel Engine

2007

The performance of a spark ignition engine strongly depends on the phase of the combustion process with respect to piston motion, and hence on the spark advance; this fundamental parameter is actually controlled in open-loop by means of maps drawn up on the test bench and stored in the Electronic Control Unit (ECU). Bi-fuel engines (e.g. running either on gasoline or on natural gas) require a double mapping process in order to obtain a spark timing map for each of the fuels. This map based open-loop control however does not assure to run the engine always with the best spark timing, which can be influenced by many factors, like ambient condition of pressure, temperature and humidity, fuel p…

Effectively and efficiently supporting crowd-enabled databases via NoSQL paradigms

2013

In this paper we provide an overview of the Hints From the Crowd (HFC) project, whose main goal is to build a NoSQL database system for large collections of product reviews; the database is queried by expressing a natural language sentence; the result is a list of products ranked based on the relevance of reviews w.r.t. the natural language sentence. The best ranked products in the result list can be seen as the best hints for the user based on crowd opinions (the reviews). The HFC prototype has been developed as a web application, independent of the particular application domain of the collected product reviews. Queries are performed by evaluating a text-based ranking metric for sets of re…

A COMPARISON BETWEEN COMBUSTION PHASE INDICATORS FOR OPTIMAL SPARK TIMING

2008

The closed-loop control of internal combustion engine spark timing may be accomplished by means of a combustion phase indicator, i.e., a parameter, derived from in-cylinder pressure analysis, whose variation is mainly referable to combustion phase shift and assumes a fixed reference value under optimal spark timing operation. The aim of the present work is a comparison between different combustion phase indicators, focusing on the performance attainable by a feedback spark timing control, which uses the indicator as pilot variable. An extensive experimental investigation has been carried out, verifying the relationship between indicators’ optimal values and the main engine running parameter…

An Online Observer for Minimization of Pulsating Torque in SMPM Motors.

2015

A persistent problem of surface mounted permanent magnet (SMPM) motors is the non-uniformity of the developed torque. Either the motor design or the motor control needs to be improved in order to minimize the periodic disturbances. This paper proposes a new control technique for reducing periodic disturbances in permanent magnet (PM) electro-mechanical actuators, by advancing a new observer/estimator paradigm. A recursive estimation algorithm is implemented for online control. The compensating signal is identified and added as feedback to the control signal of the servo motor. Compensation is evaluated for different values of the input signal, to show robustness of the proposed method.

Questions and answers on AdWords’ cases.

2012

IMPLICACIONES DEL USO DE BUSCADORES EN EL COMPORTAMIENTO DE COMPRA ONLINE / IMPLICATIONS OF THE SEARCH ENGINES USE IN THE ONLINE SHOPPING BEHAVIOUR

2009

El objetivo del presente trabajo es analizar los factores que influyen en el uso de buscadores y su incidencia en el comportamiento de compra en Internet. El análisis de resultados obtenidos a partir de una muestra representativa de 485 compradores por Internet españoles, pone de manifiesto que los consumidores que consideran la comodidad, reducciones de precio y amplitud de surtido como motivaciones relevantes para realizar compras online presentan una mayor predisposición al uso de buscadores en la realización de sus compras virtuales. La experiencia como internauta y como comprador en Internet son factores que influyen negativamente en el uso de buscadores para la realización de compras …

A Trusted Hybrid Learning Approach to Secure Edge Computing

2021

Securing edge computing has drawn much attention due to the vital role of edge computing in Fifth Generation (5G) wireless networks. Artificial Intelligence (AI) has been adopted to protect networks against attackers targeting the connected edge devices or the wireless channel. However, the proposed detection mechanisms could generate a high false detection rate, especially against unknown attacks defined as zero-day threats. Thereby, we propose and conceive a new hybrid learning security framework that combines the expertise of security experts and the strength of machine learning to protect the edge computing network from known and unknown attacks, while minimizing the false detection rat…

IMPLICACIONES DEL USO DE BUSCADORES EN EL COMPORTAMIENTO DE COMPRA ONLINE

2009

RESUMENEl objetivo del presente trabajo es analizar los factores que influyen en el uso de buscadores y su incidencia en el comportamiento de compra en Internet. El análisis de resultados obtenidos a partir de una muestra representativa de 485 compradores por Internet españoles, pone de manifiesto que los consumidores que consideran la comodidad, reducciones de precio y amplitud de surtido como motivaciones relevantes para realizar compras online presentan una mayor predisposición al uso de buscadores en la realización de sus compras virtuales. La experiencia como internauta y como comprador en Internet son factores que influyen negativamente en el uso de buscadores para la realización de c…

Supercharging the Double-Fueled Spark Ignition Engine: Performance and Efficiency

2017

Internal combustion engine development focuses mainly on two aspects: fuel economy improvement and pollutant emissions reduction. As a consequence, light duty spark ignition (SI) engines have become smaller, supercharged, and equipped with direct injection and advanced valve train control systems. The use of alternative fuels, such as natural gas (NG) and liquefied petroleum gas (LPG), thanks to their lower cost and environmental impact, widely spread in the automotive market, above all in bifuel vehicles, whose spark ignited engines may run either with gasoline or with gaseous fuel. The authors in previous works experimentally tested the strong engine efficiency increment and pollutant emi…

FE Calculation Methodology for the Thermodynamic Fatigue Analysis of an Engine Component

2006

Thermo mechanical fatigue problem is treated to define an analysis methodology permitting the strength evaluation by reliability viewpoint. The main difficulty is the lack of both theoretical and experimental information; consequently the problem is treated verifying continually the validity and the limits of the developing solution method. The main task of the activity described in this paper was the development of a numerical methodology, based on FE analyses, for the evaluation of the structural behavior of engine components subjected to thermo mechanical fatigue phenomena. The chosen application was the exhaust manifold of an IC engine; FE analyses were executed following the standard m…