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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Athena - En intelligent och flexibel säkerhetslösning för transportbranschen

Larsson, Rasmus, Hallberg, Johan January 2009 (has links)
<p>The project team has chosen to carry out the project itself. This is to be able to work more flexibly in the product development process and not be guided by some guidelines.</p><p>Every day, we read in the media about a new truck burglary. The problem has become so common that we do not even notice it in the media. Each year the theft of 1 billion of Sweden and the entire 82 billion in Europe in 2008. This is an increase of 10 billion by 2007. However, reducing the number of crimes committed but the value of thefts increases. This, in turn, creates an unsafe working environment for both truck operators and drivers. With this information, it is clear that the truck industry is in urgent need of a new more reliable security product.</p><p>Throughout the project has worked with technologists to create a wide network of contacts with representatives from all stages of transport. This has resulted in technologists had a broad aspect of how widespread the problem is and what is demanded by the market. The project has during the whole project worked to Athena should be as automatic as possible. This is not the drivers or truck have to press some unnecessary buttons to activate the system or any of its functions. This is to facilitate for the drivers so much and also to streamline the shipment as much as possible. The group has in the project worked to Athena to be constantly active. It should never play any role if the cause is at an unattended location or at a terminal, it will always be automatically monitored.</p><p>With the help of the group's specifications, observations, and all information collected Athena has been developed. The project began in early stage testing Athena with successful results. These results have in turn been shown in various seminar Police have kept in and also the Länsförsäkringar Halland to use Athena as the only security product in their briefings of the haulage industry.</p>
2

Athena - En intelligent och flexibel säkerhetslösning för transportbranschen

Larsson, Rasmus, Hallberg, Johan January 2009 (has links)
The project team has chosen to carry out the project itself. This is to be able to work more flexibly in the product development process and not be guided by some guidelines. Every day, we read in the media about a new truck burglary. The problem has become so common that we do not even notice it in the media. Each year the theft of 1 billion of Sweden and the entire 82 billion in Europe in 2008. This is an increase of 10 billion by 2007. However, reducing the number of crimes committed but the value of thefts increases. This, in turn, creates an unsafe working environment for both truck operators and drivers. With this information, it is clear that the truck industry is in urgent need of a new more reliable security product. Throughout the project has worked with technologists to create a wide network of contacts with representatives from all stages of transport. This has resulted in technologists had a broad aspect of how widespread the problem is and what is demanded by the market. The project has during the whole project worked to Athena should be as automatic as possible. This is not the drivers or truck have to press some unnecessary buttons to activate the system or any of its functions. This is to facilitate for the drivers so much and also to streamline the shipment as much as possible. The group has in the project worked to Athena to be constantly active. It should never play any role if the cause is at an unattended location or at a terminal, it will always be automatically monitored. With the help of the group's specifications, observations, and all information collected Athena has been developed. The project began in early stage testing Athena with successful results. These results have in turn been shown in various seminar Police have kept in and also the Länsförsäkringar Halland to use Athena as the only security product in their briefings of the haulage industry.
3

The Miller Cycle on Single-Cylinder and Serial Configurations of a Heavy-Duty Engine / Millercykeln i en Encylindrig och Flercylindrig Lastbilsmotor

Venkataraman, Varun January 2018 (has links)
I jämförelse med sina föregångare, har moderna lastbilsmotorer genomgått en betydandeutveckling och har utvecklats till effektiva kraftmaskiner med låga utsläpp genom införandet avavancerade avgasbehandlingssystem. Trots att de framsteg som gjorts under utvecklingen av lastbilsmotorer har varit betydande, så framhäver de framtida förväntningarna vad gällerprestanda, bränsleförbrukning och emissioner behovet av snabba samt storskaliga förbättringar av dessa parametrar för att förbränningsmotorn ska fortsätta att vara konkurrenskraftig och hållbar. Utmaningen i att uppfylla dessa till synes enkla krav är den invecklade, ogynnsammabalansgång som måste göras mellan parametrarna. Förbränningsmotorns kärna är förbränningsprocessen, som i sin tur är kopplad till motorns luftbehandlings- och bränsleregleringssystem. I denna studie undersöks Millercykeln som en potentiell lösning till att nå de motstridiga kraven för framtida lastbilsmotorer, framförallt med fokus på potentialen att förbättra prestandan samtidigt som NOx-emissionerna hålls på konstantnivå. Traditionellt har utvärderingen av Millercykeln utförts på encylindriga forskningsmotorer, vilket också har utgjort utgångspunkten i denna studie. Även om studier på flercylindriga simuleringsmodeller och forskningsmotorer har gjorts med konstanta inställningar för Millercykeln, så utförs de inte i samband med undersökningar av encylindriga motorer. Dessutom så möts inte kraven från insugssystemet på samma sätt mellan de olika motorkonfigurationerna. Denna studie undersöker och jämför potentialen för ökad prestanda med Miller-cykeln mellan encylindrig och flercylindrig motorkonfiguration för en lastbilsmotor med ett tvåstegs turboladdningssystem, som representerar ett realistiskt insugssystem som möjliggör implementeringen av Millercykeln. För att undersöka motorprestationen så används i denna studie den kommersiella mjukvaran GT-Power. Ytterligare resultat från studien innefattar kvantifiering av prestandakraven för ett högeffektivt tvåstegs turboladdningssystem och dess inverkan på temperaturen i inloppet till avgasbehandlings-systemet. En kvalitativ förståelse av betydelsen av interaktionen mellan cylindrar och effekten på cylinder-cylinder variationer med Millercykel utfördes också i simuleringar med flercylindrig motorkonfiguration. Studien utvärderade Millertiming inom ett intervall på -90 till +90 graders vev vinkel från utgångsvinkeln för stängning av insugsventilen. Utvärderingen utfördes vid systemjämvikt vid en fullastpunkt (1000RPM), där basfallet för både encylindrig och flercylindrig motor för utvärdering av Millercykeln var det välkända fallet med konstant specifik NOx. Ett ytterligare fall framhäver NOx-reduktionspotentialen med Miller vid konstant EGR-flöde på en encylindrig konfiguration. Fallen med ökad prestation realiserades genom att öka lufttillförseln, bränslemängden och det geometriska kompressionsförhållandet. Maximal prestandaökning observerades i fallet med ökad bränslemängd, och endast i detta fall utvärderades även konfigurationen med fler cylindrar för jämförelse av prestationsförbättringen med en encylindrig motsvarighet med Millertiming. Den flercylindriga motorn innefattade EGR som en lågtryckskrets, och medan detta antagande förenklade i avseende på modellering och kontroll, så var det till fördel för konfigurationen meden flercylindrig motor (jämfört med encylindrig) på grund av reducerade pumpförluster. Som påföljd gjordes en jämförande undersökning med encylinder-modellen med motsvarande mottryck för flercylinder-modellen inställt som gränsvärde. Resultaten visar att encylindermodellen representerar medelvärdet för cylindrarna i flercylinder-motorn när lämpligagränsvillkor tillämpas som kontrollparametrar. Studien ger en grund för jämförelse av Millertiming på encylindrig samt flercylindriga konfigurationer, samtidigt som kraven på insugssystemet fastställs och utgör en utgångspunkt föratt utvärdera Millercykeln och bestämma insugssystemets krav för hela motorns arbetsområde. / Modern heavy-duty engines have undergone considerable development over their predecessors and have evolved into efficient performance machines with a reducing emission footprint through the incorporation of advanced aftertreatment systems. Although, the progress achieved in heavy-duty engine development has been significant, the future expectation from heavy-duty engines in terms of performance, fuel consumption and emissions stresses the need for rapid large-scale improvements of these metrics to keep the combustion engine competitive and sustainable. The challenges in resolving these apparently straightforward demands are the intricate unfavourable trade-off that exists among the target metrics. The core of the combustion engine lies in the combustion process which is inherently linked to the air handling and fuel regulating systems of the engine. This study explores adopting the Miller cycle as a potential solution to the conflicting demands placed on future heavy-duty engines with an emphasis on the performance enhancement potential while keeping the specific NOX emission consistent. Traditionally, evaluation of the Miller cycle is performed on single-cylinder research engines and formed the starting point in this study. While studies on full-engine simulation models and test engines with fixed Miller timing have been evaluated, they appear to be performed in isolation of the favoured single-cylinder approach. Additionally, the charging system requirements are not consistently addressed between the two approaches. This study investigates and contrasts the performance enhancement potential of the Miller cycle on single-cylinder and serial enginemodels of a heavy-duty engine along with a two-stage turbocharging system to represent a realistic charging system that enables implementation of Miller timing. The commercial engine performance prediction tool GT-Power was used in this study. Additional outcomes of the study included quantifying the performance demands of a high efficiency two-stage turbocharging system and its impact on the inlet temperature of the exhaust aftertreatment system. A qualitative understanding of the significance of cylinder interaction effects on cylinder-cylinder variations with Miller timing was also performed on the serial engine cases. The study evaluated Miller timing within a range of -90 to +90 CAD from the baseline intake valve close angle. The evaluation was performed at steady-state operation of the engine at one full load point (1000RPM) wherein both the single-cylinder and serial engine Miller evaluation included a base case which characterises the Miller effect for constant specific NOX. An additional case highlights the NOX reduction potential with Miller for a constant EGR rate on the single-cylinder configuration. The performance enhancement cases were realised by increasingthe air mass, fuel mass and the geometric compression ratio. Maximum performance increase was observed in the increased fuel mass case and only this case was evaluated on the serial engine for contrasting single-cylinder and serial engine performance enhancement with Miller timing. The serial engine incorporated EGR as a low-pressure circuit and while this simplified modelling and controller considerations, it led to biasing of results in favour of the serial engine configuration (over the single-cylinder) due to reduced pumping loss. A subsequent comparison case was evaluated on the single-cylinder model with backpressure settings from the serial engine model. The results show that the single-cylinder model is representative of the cylinder averaged responses of the serial engine when appropriate boundary conditions are imposed as controller targets. The study provides a basis for contrasting Miller timing on single-cylinder and serial configurations while determining the charging system requirements and presents a starting point to evaluate Miller timing and determine air system demands over the entire engine operating range.
4

Truck electrification : Trends and impacts on the energy system

NORDHAMMER, CAROLINE, GRANKVIST, JESSICA January 2021 (has links)
In line with the Paris agreement, Sweden has set up a national emission reduction target for the transport sector; to reduce the emissions by 70% by 2030, relative to levels in 2010. This entails that large shares of road transport will be electrified, including shares of the national truck fleet. In parallel with this, the Swedish transmission grid suffers from power capacity shortages, limiting the amount of electricity that can be distributed to a regional and local level, especially in urban areas, such as Stockholm. In line with this, the aim of this thesis is to investigate the trends of truck electrification in the Stockholm region and to assess its potential impact on the electrical grid based on truck operation characteristics. To achieve this, three objectives were set; to investigate truck fleet operators’ operations and view in relation to electrification, examine truck manufacturers' views on truck electrification and to analyse the truck electrification’s potential impact on the electrical grid in future scenarios. Quantitative and qualitative methods were used to fulfil the research objectives including interviews and casestudy modelling. The results from the interviews show that both manufacturers and truck fleet operators see the electrical grid and deployment of charging infrastructure, as well as the economy of the electric truck as the main barriers to overcome in relation to truck electrification. The truck manufacturers have taken on a leading role and are together with early adopters pushing the development forward. Nonetheless, they cannot create all the right conditions themselves, as for instance charging opportunities in relation to the electric grid is a complex problem. The industry agreed upon that city transports will be electrified first followed by regional transport and lastly long-distance transport. Furthermore, 2030 was identified as a key year for truck electrification. Finally, manufacturers and truck fleet operators urge the government to act and implement necessary measures to support the transition. The results from the case-study modelling show that lunchtime charging of city transport coincides with already critical hours for the electrical grid. Moreover, the afternoon charging of city, regional and long-distance transports generates a peak during the most critical hour around 6 PM, implying that it could entail challenges for an already congested grid. In line with this, proper night-time charging is considered as crucial both from an operational (in terms of minimising the daily stops) and grid point of view (in terms of avoiding grid congestion during critical hours). In addition, it is recommended to prioritise charging of long-distance transport during the day as they often are operative around-the-clock. Although this study resulted in general charging profiles, this gives a good indication on what impact the truck electrification might have on the electrical grid. Furthermore, it gives a general picture of how the electrification of trucks could play out in Stockholm, which can be applied in other urban areas in Sweden that are facing similar challenges. / I linje med Parisavtalet har Sverige satt upp nationella utsläpps reduktionsmål för transportsektorn; att reducera utsläppen med 70% till 2030, relativt nivåerna 2010. Detta medför att stora delar av transportsektorn kommer att elektrifieras, inklusive stora delar av den nationella lastbilsflottan. Parallellt med detta lider det svenska transmissionsnätet av kapacitetsbrist vilket begränsar mängden elektricitet som kan överföras till en regional och lokal nivå, speciellt i urbana områden såsom Stockholm. I linje med detta har syftet med denna studie varit att undersöka trender inom lastbils-elektrifiering i Stockholmsregionen och att utvärdera dess potentiella inverkan på elnätet baserat på lastbilars operativa mönster. För att uppnå detta sattes tre mål upp; att undersöka lastbils-operatörers verksamhets mönster och deras syn på elektrifiering, att undersöka lastbilstillverkares syn på elektrifiering och att analysera lastbils-elektrifieringens potentiella inverkan på energisystemet i framtida scenarier. Kvantitativa och kvalitativa metoder användes för att uppnå studiens mål inklusive; intervjuer och fallstudie modellering. Resultaten från intervjuerna visar att både lastbils-operatörer och tillverkare ser elnätet och utbredningen av laddinfrastruktur, såväl som totalekonomin av den elektriska lastbilen som de huvudsakliga barriärerna att överkomma vid en elektrifiering. Lastbilstillverkare har tagit en ledande roll och driver utvecklingen av elektriska lastbilar framåt med hjälp av så kallade early adopters. Däremot kan de inte skapa alla förutsättningar själva då till exempel laddnings möjligheter i relation till elnätet är en komplex fråga. Industrin är eniga om att city transporter kommer att elektrifieras först, följt av regionala och till sist fjärrtransporter. Vidare kunde 2030 identifieras som ett nyckelår för elektrifieringen. Slutligen uppmanar både tillverkare och lastbils operatörer regeringen att implementera nödvändiga åtgärder för att stötta och påskynda omställningen. Resultaten från modelleringen i fallstudien visar att lunch-laddning för city transporter sammanfaller med redan kritiska timmar för elnätet. Dessutom genererar eftermiddagsladdningen av city, regionala och fjärrtransporter, en effekttopp runt klockan 18 vilket skulle kunna medföra utmaningar för ett redan överbelastat elnät. I linje med detta anses natt-laddning vara avgörande både från en operativ synpunkt (i form av att minimera de dagliga stoppen) och från ett elnäts perspektiv (i form av att undvika överbelastning av nätet under redan kritiska timmar). Därtill, rekommenderas att fjärrtransporter prioriteras för dagtids-laddning då de ofta är operative dygnet runt. Trots att denna studie resulterade i generella ladd-profiler kan dessa ge en god indikation för vilken inverkan lastbils-elektrifieringen kan komma att ha på elnätet. Vidare, ger studien en generell bild över hur lastbils-elektrifieringen kan komma att se ut i Stockholmsregionen vilket kan tillämpas i andra urbana områden i Sverige som står inför liknande utmaningar.

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