Sök:

Sökresultat:

744 Uppsatser om Engine testing - Sida 6 av 50

CFD simulering av en fyrtakts Otto motorcykel motor

This thesis deals with the numerical 3D simulation of a four stroke, spark-ignited, internalcombustion engine, which is mounted on a high performance motorcycle. The work, carried outin collaboration with Politecnico di Milano and MV Agusta, focuses on the simulation of theintake, compression and expansion stroke, including combustion simulation, using an opensource CFD code.Simulation of internal combustion engines offers a great challenge in the field of CFD research.Moving boundaries of the solution domain, caused by the motion of the piston and valves, leadsto deformation of the computational grid, with decreasing quality of the solution as result. Basedon this, a previously developed mesh motion strategy was employed where a number of meshesare used to cover the whole simulation cycle. Within each mesh interval the internal cell pointsof the mesh are moved to account for the boundary motion of the piston and valves. This strategywas previously applied to simplified geometries as well as real engine geometries.

VVA-strategier för avgastemperaturhöjning på en HD-Dieselmotor

Regulations on the exhaust emissions of HD-diesel engines are becoming more and more stringent, and therefore, emission after-treatment systems are commonly used. These systems rely on catalytic conversion of NOx,CO , and HC emissions, and are thus dependant on temperature. At low load of the engine, exhaust temperatures are not sufficient for the after-treatment components. Therefore, means to increase the exhaust temperature while maintaining low emissions and fuel consumption are needed.The focus of this project has been to develop strategies for the lift profiles of exhaust and intake valves in the engine, with the goal to raise exhaust temperature in combination with low emissions and fuel consumption. The strategies have been tested in a single-cylinder research engine equipped with a hydraulic variable valve actuation system.

Att göra eller inte göra : Hur kontroll och nyfikenhet påverkar regelverket på Facebook

This paper is a literature study on search engine optimization (SEO) considering the leader of the search engine market: Google. There´s an introductory background description of Google and its methods of  crawling the Internet and indexing the web pages, along with a brief review of the famous PageRank algorithm. The purpose of this paper is to describe the major important methods for improved rankings on Google´s result lists. These methods could be categorized as on-page methods tied to the website to be optimized or off-page methods that are external to the website such as link development. Furthermore the most common unethical methods are described, known as ?black hat?, which is the secondary purpose of the text.

Reglerstrategi för fria ventiler : ? Utveckling av en fyrtakts förbränningsmodell för att prediktera optimala ventilinställningar

As emission legislations across the world continuously pushes engine development forward,engineers constantly need to come up with and implement fuel saving technologies. During thelast decade, variable cam phasing has become a popular solution to increase gas exchangeefficiency. This configuration is typically mechanically constrained by camshaft limitations, anda solution to circumvent this problem would be to use a different valve actuation principle.One example of this is to use pressurized air controlled by electrical solenoids. Such a systemhas been developed byCargine Engineering and this provides the starting point for this work. Tobe able to operate the valvetrain on an actual engine, a control system is needed.

Akademiska söktjänster: En jämförande studie av Google Scholar, MEDLINE och Web of Science

The purpose of this paper is to compare the three search engines Web of Science, Google Scholar and MEDLINE in regards of recovery efficiency and the overlap of relevant documents when it comes to information searching for academic purposes. Furthermore, it raises the question whether freely available search engines and licensed search engines are interchangeable with each other. The empirical data in this study were collected through searches conducted in the three search engines Web of Science, Google Scholar and MEDLINE. Twenty search queries were used and the first twenty retrieved documents for each query were examined for relevance using previously designed criteria. The documents were scored by a binary relevancy scale and thereafter a precision value for each search engine was calculated.

Effekter av sedering med dexmedetomidin och butorfanol på hudreaktivitet vid intradermaltest på friska hundar

The effects of dexmedetomidine and butorphanol sedation on skin reactivity during intradermal testing in healthy dogs were evaluated. The effects of dexmedetomidine and butorphanol were compared to medetomidine, a sedative agent having scientific proof of not interfering with skin test reactivity, in a randomised, double blind, cross over study performed on 8 adult dogs. The dogs were sedated with medetomidine (Domitor vet.®, 0,01 ml kg-1) intravenously, or dexmedetomidine and butorphanol intramuscularly (Dexdomitor vet.®, 0,01 ml kg-1; Dolorex vet., 0,01 ml kg-1) after which they received intradermal injections of positive control solutions (histamine 0,1 mg ml-1, 0,05 mg ml-1, 0,025 mg ml-1), a negative control solution (0,9 % NaCl) and allergen extract (Dermatophagoides farinae, Cladosporium and Artemisia vulgaris). After a wash out period the trial was repeated with a reversed sedation protocol.Skin reactivity (wheal size, induration and erythema) and quality of sedation (immobilization, response to stimuli and injections as well as over all working conditions) were evaluated. The combination of dexmedetomidine and butorphanol provided reliable, good sedation and analgesia without adverse effects.

Konditionstester i rehabiliteringssammanhang : - En litteraturöversikt

During the past few years there has been an observed decrease in physical fitness within different patient groups. As a part of the rehabilitating physiotherapy treatment it is important to acknowledge the physical condition of the patient. Physical fitness testing might be difficult due to physical limitations within different patient groups. A broad range of exercise tests is therefore of importance in clinical practice. The aim of this overview was to describe exercise tests used in rehabilitation contexts, and to define areas of use and restrictions.

Beslutsmodell för inköp och lagerhållning av motorer i ett produktionssystem : En fallstudie på Sandvik

AbstractIt is important to choose which spare parts to keep in stock. With the right spareparts in stock the costs for inventory and production loss will decrease. Cavalieri et al. (2008) highlights that the balance between inventory cost and production loss is underestimated.  It affects the company and must be considered before decision on purchase.The problem with spare engines is that they are all more or less critical for the production. That can be a reason for why no previous research targeting engines and classification of with engine should be kept in stock has been found.

Pragmatisk mjukvarutestning : Hur kan agila metoder implementeras i ett pågående utvecklingsprojekt?

There are several ways of conducting software testing where some may include users and others may include personnel whose work task is to execute test on systems. Although most developers and project managers understand the point of testing the system, it is not always being done and the most common reason is that there is no time for it. However, this is a false assumption as it may instead cause some bugs in the system that would not have been there in the first place if tests had been there to prevent bugs in the code.My purpose for this thesis was to find suggestions for changes in the development process in an ongoing project used by Acino and Svenska Försäkringsfabriken in order to increase the quality of the system used. In this thesis, I have approached the purpose by pursuing a case study of the two companies through observation and interviews. By doing this I acquired the relevant information to make suggestions for change.

Utvärdering av laddningskoncept för lastbilsbatterier

When drivers overnight in the truck lots of electric energy is consumed by heaters, fans, lights and other extra equipment. If the engine is not running, this energy is taken from the lead/acid batteries of the truck which then needs to be recharged during operating hours. The fact that the charge acceptance of the lead/acid batteries is dependent on the temperature makes it hard to fully recharge the batteries at lower temperatures. A negative charge balance can lead to starting problems within a few days use in cold climate.In this thesis work, the effects of different battery charging concept are evaluated on the most common Scania battery (175Ah). A battery model is implemented in Matlab and some simulations of charging are made.

Deterministisk Komprimering/Dekomprimering av Testvektorer med Hjälp av en Inbyggd Processor och Faxkodning

Modern semiconductor design methods makes it possible to design increasingly complex system-on-a-chips (SOCs). Testing such SOCs becomes highly expensive due to the rapidly increasing test data volumes with longer test times as a result. Several approaches exist to compress the test stimuli and where hardware is added for decompression. This master?s thesis presents a test data compression method based on a modified facsimile code.

VÄRDEFLÖDESANALYS AV PW1000G 30k TEC

The thesis work has been carried out at Volvo Aero Corporation (VAC) in Trollhättan. VAC has entered a partnership as developing and producing partner with engine manufacturer Pratt & Whitney and is currently at the starting phase of producing the turbine rear frame (TEC) to the engine PW1000.The purpose of this study was to create a report on process level that describes the conditions and the potential with PW1000 TEC to reach the product cost calculation taking into account lead times and describe alternative method solutions.The report describes a comparison between the present flow (2012), a flow based on product cost calculation (2016) and a potential flow (2016). The work has mainly been based on acquiring the knowledge and information available to inspect the present flow; this has been done by workshop observations, meetings and gathering of the information that is available on the work site for the PW1000 TEC.The information obtained has been merged into an Excel document, called Roadmap. It serves as a roadmap with current situation as the start and the potential flow for 2016 as the goal. With the roadmap as a tool, assumptions have been taken considering the flow and how it will change, where processes have been eliminated, reduced or marked as a problem..

Google Bilders användbarhet : Gränssnitt, sökfunktioner och återvinning

This essay explores to what extent the Swedish language version of Google Images meets the usability requirements of average everyday users. Previously published studies on user behaviour and users? interface and search option preferences define the usability requirements, which are matched against Google Images? actual interface and search options. The retrieval method of Google Images is also briefly discussed, and users? opinions about Google Images too, as they come across in the previously published user studies.The findings are that Google Images lack some of the things that users ask for, but it still seems to be the most used image search engine among average internet users and more appreciated than other search engines.

Konstruktion av styrelektronik till testfixtur

The focus of this thesis is primarily in electronic construction and describes the design process for a microcontroller circuit board from concept development to prototyping. The client develops test fixtures for automated testing of products within the electronics industry and needs a new controller circuit for the test fixtures that can handle controls and basic testing. An investigation into the needs of such a system is conducted and a prototype printed circuit board assembly is manufactured.The prototype is developed with focus on protection against electrostatic discharges and overvoltage. Among the functions that are included are voltage measurements, communication interfaces and control of input and output currents. Firmware for the prototype is developed and configured to communicate with a PC through USB interface for control and collecting of measurements..

Utdragshållfasthet hos limmade och olimmade gängstänger i limträ

This essay examines pull-out strength of threaded rods fixed into glulam timber. The technology is intended to be used in hidden joints between glulam components. The work began with a study of literature focusing on current research within the topic, mainly to create a base of knowledge before the testing was initiated. Studies of scientific articles reveals a lack of research within this area, which makes it difficult to develop standards and calculation models for these joints. The drill holes in the tests have a diameter of 7 mm.

<- Föregående sida 6 Nästa sida ->