This thesis is about modelling of the combustion and emissions of dual fuel HCCI engines for design of “engine combustion system”. For modelling the combustion first the laminar flamelet model and a hybrid Lagrangian / Eulerian method are developed and implemented to provide a framework for incorporating detailed chemical kinetics. This model can be applied to an engine for the validation of the chemical kinetic mechanism. The chemical kinetics, reaction rates and their equations lead to a certain formula for which the coefficients can be obtained from different sources, such as NASA polynomials [1]. This is followed by study of the simulation results and significant findings. Finally, for investigation of the knock phenomenon some characteristics such as compression ratio, fuel equivalence ratio, spark timing and their effects on the performance of an engine are examined and discussed. The OH radical concentration (which is the main factor for production of knock) is evaluated with regard to adjustment of the above mentioned characteristic parameters. In the second part of this work the specification of the sample engine is given and the results obtained from simulation are compared with experimental results for this sample engine, in order to validate the method applied in AVL Fire software. This method is used to investigate and optimize the effects of parameters such as inlet temperature, fuels ratio, diesel fuel injection timing, engine RPM and EGR on combustion in a dual fuel HCCI engine. For modelling the dual fuel HCCI engine AVL FIRE software is applied to simulate the combustion and study the optimization of a combustion chamber design. The findings for the dual fuel HCCI engine show that the mixture of methane and diesel fuel has a great influence on an engine's power and emissions. Inlet air temperature has also a significant role in the start of combustion so that inlet temperature is a factor in auto-ignition. With an increase of methane fuel, the burning process will be more rapid and oxidation becomes more complete. As a result, the amounts of CO and HC emissions decrease remarkably. With an increase of premixed ratio beyond a certain amount, NOX emissions decrease. With pressure increases markedly and at high RPM, knock phenomenon is observed in HCCI combustion.

This thesis is about modelling of the combustion and emissions of dual fuel HCCI engines for design of “engine combustion system”. For modelling the combustion first the laminar flamelet model and a hybrid Lagrangian / Eulerian method are developed and implemented to provide a framework for incorporating detailed chemical kinetics. This model can be applied to an engine for the validation of the chemical kinetic mechanism. The chemical kinetics, reaction rates and their equations lead to a certain formula for which the coefficients can be obtained from different sources, such as NASA polynomials [1]. This is followed by study of the simulation results and significant findings. Finally, for investigation of the knock phenomenon some characteristics such as compression ratio, fuel equivalence ratio, spark timing and their effects on the performance of an engine are examined and discussed. The OH radical concentration (which is the main factor for production of knock) is evaluated with regard to adjustment of the above mentioned characteristic parameters. In the second part of this work the specification of the sample engine is given and the results obtained from simulation are compared with experimental results for this sample engine, in order to validate the method applied in AVL Fire software. This method is used to investigate and optimize the effects of parameters such as inlet temperature, fuels ratio, diesel fuel injection timing, engine RPM and EGR on combustion in a dual fuel HCCI engine. For modelling the dual fuel HCCI engine AVL FIRE software is applied to simulate the combustion and study the optimization of a combustion chamber design. The findings for the dual fuel HCCI engine show that the mixture of methane and diesel fuel has a great influence on an engine's power and emissions. Inlet air temperature has also a significant role in the start of combustion so that inlet temperature is a factor in auto-ignition. With an increase of methane fuel, the burning process will be more rapid and oxidation becomes more complete. As a result, the amounts of CO and HC emissions decrease remarkably. With an increase of premixed ratio beyond a certain amount, NOX emissions decrease. With pressure increases markedly and at high RPM, knock phenomenon is observed in HCCI combustion.

Freight transport is a large contributor to emissions of CO2 and to mitigate its environmental impact is essential in strive for a sustainable future. Existing reports usually discuss the issues from a national or global perspective, but rarely provide any concrete or practical information on an organizational level. This report aims to describe the key driving factors of CO2 emissions caused by freight transport and recommend suitable measures for organizations to mitigate their environmental impact. To do this, a case study at Atlas Copco’s business area Industrial Technique (ITBA) is performed, four different business scenarios are created and the emissions from the scenarios are simulated. ITBA is a decentralized organization with most of the production sites and sub suppliers in Europe. Over 90% of the finished goods are sent to a distribution center in Belgium and then delivered to the customers. Today, most customers are located in Europe and this market accounts for nearly 80% of the distributed weight. However, ITBA believe in a strong growth in the North American and Asian markets and that the customer base will look much different in 2020. More customers at longer distances from the distribution center will lead to a heavily increased use of air freight, resulting in higher emission levels. This study shows a clear correlation between the total CO2 emissions and the share of air freight. In order for ITBA to expand their business and at the same time lower their emissions, actions are required. This report shows that a lower share of air freight and the use of several decentralized distribution centers can reduce the emissions significantly. Other means to lower the emissions include relocation of production sites, education to increase the awareness within the organization and including environmental performance when evaluating third party logistics.

Getriebe wandeln Drehmomente um; es treten hierbei Kräfte an den Zahnrädern auf. Bei einer Schrägverzahnung wirken neben Radialkräften auch Axialkräfte. Axiale und radiale Lagerkräfte sind die Reaktion auf die Zahnkräfte. Hohe Zahnkräfte können zu Verzahnungsschäden führen. Hohe Lagerkräfte verursachen Lagerverschleiß und führen zum Klappern des Lagers und zur Schallabstrahlung durch die Getriebewände. Ausgangspunkt für die Simulation eines einfachen Zwei-Räder-Systems bildet ein Torsionsschwingungsmodell mit zwei Freiheitsgraden. Die Simulationsschrittweite ergibt sich aus der Eigenfrequenz, letztere wird analytisch bestimmt. Vier Zustandsgleichungen beschreiben den Zustand des Systems zu jedem Zeitpunkt der Simulation. Das Runge-Kutta-Verfahren berechnet schrittweise den Zustandsvektor x_i+1 aus x_i. Die Eingriffssteifigkeit ändert sich während des Eingriffs und wird in jedem Schritt i neu ermittelt. Der Schwingungsverlauf der Zahnkraft erreicht nach 10 Perioden die stationäre Phase. Resonanzen treten auf, wenn die Eigenfrequenz ein ganzzahliges Vielfaches der Eingriffsfrequenz ist. Ein erweitertes Schwingungsmodell mit 6 Freiheitsgraden beinhaltet auch die Lager- und Wellenelastizitäten und die entsprechenden Dämpfungen. Eine analytische Lösung dieses Systems für den Fall nicht konstanter Eingriffssteifigkeit ist nicht zweckmäßig. ITI-SIM liefert für das einfache Torsionssystem identische Ergebnisse wie das vom Autor entwickelte Simulationsprogramm. Unter Einbeziehung der Lagersteifigkeiten in das ITI-SIM-Modell erhält man den Verlauf der Lagerkräfte. Bei einem Schrägungswinkel β>0 treten als Simulationsergebnis außerdem Axialkräfte auf. Bei Modellierung einer Momentenkennlinie am Abtrieb schwankt das Abtriebsmoment, hervorgerufen durch die Schwankung der Eingriffssteifigkeit. Um zwei Getriebestufen mit unterschiedlichen Eingriffsrichtungen im Simulationsmodell koppeln zu können, wird eine Koordinatentransformation verwendet.:Inhaltsverzeichnis Abbildungsverzeichnis Zusammenfassung Thesen Abkürzungen und Formelzeichen Vorwort 1 Präzisierung der Aufgabenstellung 2 Literaturauswertung 3 Kräfte im Getriebe 3.1 Zahnkräfte 3.1.1 Statische und dynamische Zahnkräfte 3.2 Lagerkräfte 3.2.1 Statische Lagerkräfte 3.2.2 Dynamische Lagerkräfte 3.3 Auswirkungen der Zahnkräfte 3.4 Auswirkungen der Lagerkräfte 3.4.1 Statische Kräfte 3.4.2 Dynamische Kräfte 4 Numerische Simulation eines Torsionsschwingungsmodells 4.1 Einleitung 4.2 Ziel 4.3 Modell 4.4 Bewegungsgleichungen 4.5 Statisches Verhalten 4.6 Eigenfrequenz 4.7 Zustandsgleichung 4.8 Simulation 4.9 Eingriffssteifigkeit 4.10 Dämpfungskoeffizient 4.11 Simulationsprotokollierung 4.12 Ergebnisse 5 Erweitertes Schwingungsmodell 6 ITI-SIM 6.1 Simulation mit ITI-SIM 6.2 Einfaches Torsionsschwingungsmodell 6.3 Torsionsmodell mit Zusatzmasse 6.4 Simulation des erweiterten Schwingungsmodells 6.4.1 Geradverzahnung 6.4.2 Schrägverzahnung 6.4.3 Einfluß des Lastmomentes 6.5 Erweiterung des Koordinatensystems Anhang A Die Quelldatei torsionsschwinger1.c B Die Quelldatei zahnsteifigkeit.c C Die Eingabedatei torsionsschwinger1-0.dat D Das Shell-Script eta-verlauf E ITI-Simulationsergebnisse F Simulationsergebnisse des erweiterten Modells mit Schrägverzahnung Literaturverzeichnis Sachregister