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The increasing impact of Internal combustion engines on the environment have led to some stringent rules over the automotive industry, which have forced them to have a deeper investigation into the components of the engine.Friction, oil consumption and blow-by are the major concern of the automotive industry and all of this happens at the Piston-ring pack assembly. So, through this work using 3D CFD software Star CCM+, the better understanding of the fluid mechanics in the Piston-ring pack is addressed, which could be helpful for the broad range of R&D and can also provide base for the further CFD research. A two-dimensional geometric section of the Piston-ring pack has been selected of the Gasoline engine having the operating condition of full load. The 2D Piston-ring pack has been modelled with the transient condition of Pressure and Temperature over the cycle. Dynamic mesh has been created for the kinematics and dynamics of the Piston and rings. Gas flow and oil flow in the Piston-ring pack was analysed with the dependent parameters like absolute pressure for 3 cycles, which was also compared with available MBS (Multi-body Simulation) results, Mass flow rate. Based on that, the flow pattern of the gas and oil was captured with different transport mechanism i.e. reverse flow, inertia force, squeezing, pumping. Hydrodynamic friction power loss was also studied between ring-liner gap due to shear stress in lubricating oil and the results was compared with MBS results. The resultant axial and radial force acting on the rings was also calculated and compared for all the 3 cycles. This work is the comprehensive investigation of the Piston-ring pack (2D-model) for all the important mechanism could take place in the Piston-ring pack. It constitutes a major step in understanding oil and gas dynamics in the Piston-ring pack.
This work is aimed to study the effect of two types of stresses/corrosion on different materials used in making of disc brake rotors, atmospheric corrosion and thermal fatigue. The materials chosen were steel (100Cr6), nodular cast iron (GJS-400-15) and Aluminium reinforced silicon carbide (F3S-20S). Specimens of the each material will be subjected to an induced atmospheric corrosion using the salt spray (fog) chamber for two different test durations to simulate atmospheric corrosion. Other specimens of the chosen materials will be subjected to a thermal fatigue test through a repeated heating-cooling cycle. The effects on the materials will be measured by the difference in the values of coefficient of friction and the wear rate before and after the tests are carried out. Analysis of the induced corrosion and thermal fatigue products will be carried out by XRD analysis and microscopic photos of the surfaces. A comparison between the different tested materials will also be performed.
The title of this thesis is the development of a Standardized Process Controlling and a method for the measurement of plant flexibility using the example of the Automotive Aftermarket (AA) division of the Robert Bosch GmbH. Developing the Standardized Process Controlling based on literature review and an analysis of existing procedures at the company. The approach consists of an instruction for process development and a reporting tool to control it after implementation. It is tested on three already existing processes as well as on the development of the Plant Flexibility process; establishing the Plant Flexibility measurement on the four aspects of line, volume, time and personnel capacity flexibility. In the application of the Standardized Process Controlling identified problems are used to improve and finalize the approach. As a result an easier implementation of processes as well as an evaluation of their current performance is possible.
Turbidity currents play a significant role within the global sediment cycle, and are important for environmental processes as well as the formation of hydrocarbon reservoirs. A special kind of turbidity currents are tubidity currents with reversing buoy- ancy. Hyperpycnal flows are one kind of turbidity currents with reversing buoyancy. There exist numerous experimental studies of these flows but no simulations. This thesis deals with reversing-buoyancy turbidity currents. The propagation of the flow front over time and the later lift-off are investigated on the basis of the results from Sparks et al. (1993). Furthermore the interaction of the current with obstacles is analyzed by means of the work from Stevenson & Peakall (2010). Hereby a closer look at deposit patterns caused by various obstacle positions and dimensions, is taken. Towards this end a highly parallel three-dimensional Navier-Stokes Direct Numerical Simulation code is used.
The aim of this work is the analysis of characteristic properties of fuel jets in internal combustion engines for steady and transient spray velocities by means of CFD. The simulations were done using DNS. The used software is Gerris. Calculations with different Reynolds numbers, Weber numbers and density ratios were done. The adaptations of an already existing simulation file included the implementation of necessary output capabilities. The analysis of obtained data was done by previously created macros. The obtained non-dimensional results give information on penetration, number of droplets, SMD and droplets size distribution. One calculation was compared to experimental data.
With the launch of a new vehicle model Rolls-Royce Motorcars had to face a dramatic volume increase from 300% more cars being build in existing structure and facilities in the Test and Finish Area. This massive volume increase required a revisiting of the process flow of cars through this Test and Finish Area to show optimisation potential and possible improvements to work packages and sequence of operation. Furthermore it will be necessary to implement those improvements to cope increased future throughput targets. To find optimisation and improvement potentials it was essential to analyse the entire area. In doing so every single station and work package was analysed. In addition to this a simulation model was used to confirm the highlighted problems and bottlenecks. Furthermore it was possible to investigate the influence of certain measures. In a following step it was the aim to show a way how a permanent and stable vehicle flow is achievable. According to that an action plan was developed, which shows clear measures to cope not only future but also the current production volume. In doing so it was possible to gain a transparency into the processes. Furthermore the process flow was optimised into a pull strategy to improve respectively implement a takt adherence.
In the present work of thesis, exhaust gas temperature transients of different diesel electric hybrid configurations equipped to a mid-size European passenger car were evaluated through numerical simulation. Different degrees of hybridization, from micro to mild hybrids, based on General Motors BAS powertrain architecture, enabling different hybridization strategies, were taken into account in order to obtain a preliminary assessment of the impact of micro and mild hybridization on the exhaust aftertreatment system's efficiency over the regulated New European Driving Cycle. Thereto, the simulation software GT-SUITE featuring an one dimensional code was used to build a model of the reference vehicle with conventional powertrain, to which the corresponding BAS configurations were later equipped. The simulated exhaust gas temperature transients were then compared and evaluated.
With the introduction of more and more stringent exhaust emission limitations for diesel engines by the legislation, engine and vehicle manufactures looking for solutions to meet this legislation limits with minimal hardware changes. In the present study experiments were performed to find possible solutions to meet TIER-4a emission limits without using a Diesel Particulate Filter (DPF). Two similar medium duty diesel engines were chosen to demonstrate this only by changing the fuel injection hardware and calibration. The study was divided into an investigation of the benefit of higher injection pressures while the second part concentrated on the investigation of multiple injection effects. It was found that with the use of high injection pressures from 1800 bar upwards together with high exhaust gas recirculation (EGR) rates the targets can be fulfilled with a single injection. This test was performed at the rated speed 100% load point. The multiple injection experiments demonstrated that the use of an early large pilot injection together with an close post injection can reduce the NOx and smoke emissions efficiently. It was found that with this injection strategy the TIER-4a emission targets can be achieved with a railpressure of only 1300 bar and lower EGR rate of 15% at a mid speed 75% load point (mode-6). The set of experiments also included a investigation into another efficient possibility to achieve TIER-4a emission standards with the use of a DPF but without the use of an EGR system. It was found that with the use of an early pilot injection and a retarded main injection timing it is possible to reduce the NOx formation to achieve the 3 g/kWh NOx limit.
The aim of this Diploma Thesis is the adjustment and optimization of an existing turbocharged diesel engine on the much promising HCCI (Homogeneous Charge Compression Ignition) Combustion Technique in base on adapted piston geometries and injecting strategies. This adjustment is focused on the simulation of the complete engine, while suitable simulation programs for the different subsystems of the engine. On base of the 1-D simulation routine AMESim (Imagine) the Injector of the Common Rail System, and thus the injecting behaviour is simulated. Afterwards the results are used in the 3-D CFD program FIRE (AVL), in order to represent a Single Cylinder Engine of the overall system. The Conclusion forms the simulation of the overall diesel engine on the base of the simulation routine BOOST (AVL).
The world of engineering has changed significantly over the last years. Increased time to market, cost and produce variety constraints lead, next to the introduction of new engineering technologies and tools, to the implementation of new engineering processes, such as Simultaneous Engineering. The Rover Group started with the implementation of Simultaneous Engineering Principles within their development departments at the beginning of the 90's. The requirements towards the realisation of Simultaneous Engineering within their development projects changed when the Rover Group started working and developing products with BMW in 1994. Within this Diploma the intake manifold development process for the NG4 engine, the first joint developed combustion engine between the Powertrain sections of BMW and Rover, will be analysed. The basis for the analysed. The basis for the analysis of the Simultaneous Engineering Process are SE-Principles, based on literature research, which will be estimated on their degree of realisation within the development process. In the final part of the Diploma some recommendations regarding the creation of future Powertrain Engineering processes are given, in particular, focus on the improvement of the international co-operation between the development departments of BMW and Rover Group. It is to note, a lot of basic project information used for the analysis and recommendation within this Diploma are based on UK development sources. Not all statements given within this Diploma might be valid for the Munich based BMW departments or the manufacturing section. <!-- #h:dissdiplDevelopment.doc# -->