Variable compression engines are a mean to meet the demand on lower fuel consumption. A high compression ratio results in high engine efficiency, but also increases the knock tendency. On conventional engines with fixed compression ratio, knock is avoided by retarding the ignition angle. The variable compression engine offers an extra dimension in knock control, since both ignition angle and compression ratio can be adjusted. The central question is thus for what combination of compression ratio and ignition angle the maximum efficiency is achieved, considering the set of compression ratios and ignition angles that give a sufficiently low knock intensity. Four knock detection methods are proposed, compared and evaluated with respect to robustness for noise and choices of parameter values. Three of the knock detectors are categorised as on-line, and are designed for giving feedback about knock occurrence to the engine control unit. The methods can determine both whether or not knock is present and the crank angle at knock onset. A study of the relationship between knock oscillation properties and knock-onset is performed. It is concluded that the logarithm of the normalised knock energy depends almost linearly on the rate of knock occurrence. A new formulation of multi-zone engine models is presented. The formulation makes it easy to increase or decrease the number of zones during the simulation. One of many possible applications is the investigation of engine efficiency. An analysis of experimental data shows how the engine efficiency changes with compression ratio and ignition angle. An engine torque model is developed and validated, from which the optimal choice of compression ratio and ignition angle can be calculated with high accuracy.

In an advanced avionics system, the demand of high reliability and availability is of great importance. Testability Analysis is a method of examining this. In the project RWE Tornado GE at Saab Avitronics, they use Built-In Test (BIT), for the purpose of detecting and isolating possible failures in the equipment in question. There is however the need of verification of BIT functionality. Some of the verification tests are requested by customer EADS to be simulated and demonstrated. The objective of this thesis is to understand the Testability Analysis process as well as develop a tool to assist the Testability Demonstration preparations and result recording. / Kravet på hög tillförlitlighet samt tillgänglighet är av yttersta vikt inom ett avancerat avioniksystem. Testbarhetsanalys är en undersökningsmetod som man kan tillämpa. I projektet RWE Tornado GE på Saab Avitronics använder man sig av inbyggda tester - Built-In Test (BIT) - för att kunna upptäcka och isolera eventuella felmoder i en utrustning. Utöver detta vill man verifiera att BIT-funktionen faktiskt fungerar. Vissa av dessa verifieringstester måste simuleras och demonstreras i enlighet med kunden EADS begäran. Målet med examensarbetet är att förstå testbarhetsanalysprocessen samt utveckla ett verktyg för att kunna göra nödvändiga förberedelser för samt resultatinsamling under testbarhetsdemonstrationen (T-Demo).

<p>This thesis focuses on the use of multiple redundant control surfaces to increase performance during flight. There is no clear-cut definition of performance. It may differ between applications, but here, the amount of drag for a given flight condition is used. The work is concentrated on minimizing drag with the use of measurements instead of numerical simulations. Measured data contains noise and there are problems with repeatability and hysteresis. These difficulties are considered and a method for drag minimization during flight is presented.</p><p>In the first study the drag minimization algorithm is discussed. Focus is put on describing the implemented method and the treatment of constraints to the optimization problem. The constraints include keeping the lift constant as well as having bounds on the control surface deflections.</p><p>In the second work, a more complex wind tunnel model is used to validate the drag optimization algorithm. Drag reduction for different flight conditions is studied, as well as the impact of the number of control surfaces. Different layouts of the control surfaces are also tested. The results show that the constraints are satisfied and that the drag is reduced substantially.</p>

<p>The wheel loader is a type of engineering vehicle used primarily to move crude material over shorter distances. As the vehicle is designed without wheel suspension, wheel loader drivers are exposed to high levels of whole body vibration which influences ride comfort negatively. The work presented in this thesis has the aim to investigate the potential in adding an axle suspension to a wheel loader in order to reduce vibrations and increase handling quality. While suspended axles have great potential for improving ride comfort and performance, they will also necessarily affect the vehicle dynamic behaviour which is different in many aspects from that of passenger cars or other road vehicles: the wheel loader has a large pitch inertia compared to its mass, the axle loads vary considerably with loading condition, and the vehicle uses an articulated frame steering system rather than wheel steering. These issues must all be considered in the design process for a wheel loader suspension.</p><p>The effects of suspended axles on ride vibrations are analysed by simulating a multibody wheel loader model with and without axle suspension. Results from the simulations show that longitudinal and vertical acceleration levels are greatly reduced with axle suspension, but that the decrease in lateral acceleration is smaller. By reducing the roll stiffness lateral accelerations can be further reduced, although this may not be feasible because of requirements on handling stability. The pitching oscillation of the vehicle has also been studied as this is known to have a large influence on ride comfort. An analytical model is used to study the effect of front and rear suspension characteristics on the pitching response of the wheel loader, showing that a stiffer rear suspension is favourable for reducing pitching but also that a similar effect is attainable with a stiffer front suspension. Results are compared to multibody simulations which show the same trend as analytical predictions. By including a linearised representation of a hydropneumatic suspension in the models, it is also shown that favourable dynamic behaviour can be maintained when the vehicle is loaded by utilising the fact that suspension stiffness is increasing with axle load.</p><p>Articulated vehicles may exhibit lateral oscillations known as "snaking" when driven at high speed. The effect of suspended axles on these oscillations are analysed using a multibody simulation model of a wheel loader with an equivalent roll stiffness suspension model. It is found that the roll motion of the sprung mass has a slightly destabilising effect on the snaking oscillations. This effect is more pronounced if the body roll frequency is close to the frequency of the snaking motion, although this loss in stability can be compensated for by increasing the equivalent stiffness or damping of the steering system.</p><p>Together with existing vehicle dynamic theory and design rules, the studies reported in this work provide an insight into the specific issues related to suspension design for wheel loaders.</p>

Electric vehicle technology is an interdisciplinary field in continuous development. It appears to be a margin for improvements. The Division for Electricity at Uppsala University is doing significant research in the field. The present thesis investigates electric machines for vehicular applications, both in the driveline and in the traction motor. Section 1 presents a driveline with two galvanically isolated voltage levels. A low power side is operated at the optimum voltage of the batteries, while a high power side is operated at a higher voltage leading to higher efficiencies in the traction motor. Both sides are coupled through a flywheel that stabilizes the power transients inherent to a drive cycle. A review of electric machine topologies for electric vehicles is presented in Section 2. The permanent magnet excited machine is the most suitable technology for an electric driveline. Section 3 is devoted to numerical models applied to electric machines. The equivalent circuit of a motor/generator with two sets of windings is first presented. This machine couples both sides of the driveline and drives the rotor of the flywheel. The electric parameters are calculated with custom FEM models. A discussion on slotless machines concludes with a simple model to analyze the magnetic field from one static 3D simulation. The tooth ripple losses in solid salient poles are also analyzed with a novel FEM approach. A complete description of the losses in electric machines gives a proper background for further discussion on efficiency. Section 4 presents the experimental work constructed to validate the theoretical models. The experiments include an axial flux, single wounded prototype, an axial flux, double wound prototype and a planed radial flux coreless prototype. Section 5 focuses on traction motors for electric vehicles. A simulated prototype illustrates a design and calculation process. The loss theory and the numerical methods presented in Section 3 are applied.

Sammanfattning   På lastbilsmodellerna FH och FM från Volvo, finns det vibrationsdämpare mellan karossen och frontluckan. Dessa dämpar rörelse vid en hård stängning av luckan, förhindrar att luckan ock dörren kolliderar.  De nuvarande vibrationsdämparna går inte att justera på något vis, detta vill Volvo kunna göra, för att lättare kunna justera in frontluckans position mot dörren och få en bra inpassning som ger ett bra kvalitetsintryck för kunden. Flera koncept ska tas fram för att sedan jämföras med varandra i en beslutsmatris. Arbetet utförs på Volvo GTT, konstruktionsavdelning av Volvo GTO, i Umeå.   Viktiga avgränsningar: Endast framtagning av koncept, inte någon produktion av delarna. Inga hållfasthetsberäkningar av mig eller FEM-analys. Använda mig av programvaran CATIA V5 för CAD   Vad som utförts: Marknadsundersökning har utförts mot konkurrenter och tidigare koncept framtagna av Volvo, sedan framtagning av olika koncept för vibrationsdämpare med justering i CATIA v5. De koncept som tagits fram jämförs sedan i en Pugh-matris, viktiga egenskaper som pris, tillverkningsbarhet, monteringsbarhet jämförs med den nuvarande dämparen.   Resultat av Pugh-matrisen: Koncept 2 och 4 var bäst i denna analys, båda fick lika mycket poäng i sin jämförelse, dock utfördes analysen utan en kostnadsberäkning.   Diskussion och Slutsats: Två av koncepten är bättre lämpade att fortsätta utveckla, koncept 2 och 4, detta av både kostnadsskäl samt att de kan ändras för att ge en tillräcklig justering. Koncept 1 kan användas ett kortare tag, då det löser vissa problem som de har haft vid montering. Slutsatsen är att det går att göra olika koncept med justering för vibrationsdämpare. Den svåra delen att lösa är hur man ska kunna justera dämparna med stängd frontlucka. / Vibration-dampeners for front lid FH/FM   Concepts for vibration-dampers with adjustment   Joakim Kerwien   Abstract   The model-lines FH and FM from Volvo Trucks, have vibration dampers in the front of the cab.  These dampen the front lid and reduces the risk for the front lid to slam into the door. The current vibration damper design is not position adjustable, which is something Volvo wants to have. This makes it easier to adjust the front lid, and get a good gap- and flush-positioning of the front lid, that gives an excellent quality impression for the customer. Several concepts are to be developed, which will be compared to each other in a decision matrix. The work is carried out at Volvo GTT, the design engineering branch of Volvo GTO in Umeå.   Important delimitations: Development of concepts, no production of parts yet. No strength of materials-calculations or FEM-analysis by me. Use CATIA v5 for CAD-purposes.   Work done: Market research has been done, towards rival companies, also researched some former concepts developed by Volvo employees, then I have made some different vibration dampers with adjustability in CATIA v5. The concepts developed were then put into a Pugh-matrix, where important attributes and qualities like price, manufacturability, difficulty of assembly were compared with the current damper.   Results of the Pugh-matrix: Concepts 2 and 4 were best in this analysis, both got the same amount of points, although this was without any cost analysis involved.   Discussions and Conclusions: Two of the concepts are better suited for further development, concepts 2 and 4, both from cost reasons, also they both have adequate adjustability. The conclusion is that it is feasible to make different concepts for vibration-dampers with adjustability. The hard part to solve is how you can adjust the dampeners with the front lid closed.

During the past years, several tools have been developed to try predicting wheel and rail wear of railway vehicles in an e-cient way. In this MSc thesis a new wear prediction tool developed by I.Persson is studied and compared with another wear prediction tool, developed by T.Jendel, which has been already validated and is in use since several years ago. The advantages that the new model gives are simpler structure, the consideration of wear as a continuous variable and that all the code is integrated in the same software. The two models have the same methodology until the part of the wear calculations and the post-processing. Wheel-rail geometry functions and time domain simulations are performed with the software GENSYS. In the simulation model the track and the vehicle are dened as well as other important properties such as vehicle speed and coe-cient of friction. Three simple tracks are used: tangent track, R=500 m curve with a cant of ht=0.15 m on the outer rail and R=1000 m curve with a cant of ht=0.1 m on the outer rail. The model is assumed to be symmetric so just outer (first and fourth axle) and inner (second and third axles) wheels are considered. During the vehicle-track interaction, the normal and tangential problems are solved. The wheel-rail contact is modelled according to Hertz's theory and Kalker's simplied theory with the help of the algorithm FASTSIM. Then wear calculations are performed according to Archard's wear law. It is applied in dierent ways, obtaining wear depth directly in Jendel's and wear volume rate in Persson's model. Jendel's model is rstly analyzed. Its specifc methodology is briefly explained and modications are performed on the code to make it work as similar as possible to Persson's model. Also parameters regarding the distance in which wear calculations are taken, the discretization of the width of the wheel and the discretization of the contact patch are analyzed. The methodology of Persson's model is also studied, most of all the performance of the post-processing which is one of the keys to the code. The parameters analyzed in this code are the ones regarding a statistical analysis performed during the post-processing and the discretization of the contact patch. Finally the comparisons between the wear depth obtained for both models are carried out. The discrepancies between the models are explained with the parameters analyzed and the dynamic behaviour of both models. Also a theoretical case is used as reference for comparison.

Rail wear can result in extensive costs for the track owner if it is not predicted and preventedin an efficient way. To limit these costs, one measure is to predict rail wear through wear simulations. The purpose with this work is to perform simulations of successive rail wear on the Swedish light rail line Tvärbanan in Stockholm, by means of the track-vehicle dynamics software GENSYS in combination with a wear calculation program developed in MATLAB. The simulation procedure is based on a methodology with a simulation set design, where the simulations to be performed are selected through a parametric study. The simulations include track-vehicle simulations, where the wheel-rail contact is modelled according to the Hertzian contact theory together with Kalker’s simplified theory (including the numerical algorithm FASTSIM). The results from the track-vehicle simulations serve as input to the wear calculations. When modelling rail wear Archard’s wear model has been used, including wear coefficients based on laboratory measurements. The measurements have been performed under dry conditions, so the wear coefficients under lubricated conditions (both natural and deliberate lubrication) are reduced by factors estimated by field observations. After the wear depth calculations the wear distribution is smoothed and the rail profile is updated. The simulation procedure continues with a new wear step as long as the desired tonnage is not attained. Four curves of Tvärbanan with different curve radii, ranging from 85 to 410 m, have beenstudied in this work. On three of the curves the high rail is deliberately lubricated, whereas no lubrication has been applied in the widest curve. The vehicle operating the light rail line is an articulated tram with two motor end bogies and one intermediate trailer bogie. The line was opened in August 1999 and extended in one direction one year later. Rail profile measurements have been carried out by SL since March 2002. The traffic tonnage at the selected sites from the opening of the line to the last measurement occasion (September2004) is at most 8.9 mega gross ton per track. The results of the rail wear prediction tool are evaluated by comparing worn-off area of the simulated rail profiles with that of the measured rail profiles. Simulated and measured resultsdo not agree too well, since the simulated rail wear is more extensive than the measured one, especially on the outer rail. However, the shapes of the simulated worn rail profiles are comparable to those of the measured rail profiles. / QC 20101123

To reduce cost of structural composites the development of more efficient manufacturing methods is of great interest. Sheet forming of thermoset prepreg, also known as hot drape forming, has been a promising manufacturing method for decades. An automatic tape layer (ATL) can be used to perform the lay-up in an efficient way. The flatly stacked unidirectional prepreg forms a sheet to be formed over a given mould. Knowledge about the materials forming behaviour is important to reach the required shape without flaws, such as wrinkles. An experimental approach is developed to investigate the intra- (within the layer) and interply deformation. The intraply deformation properties are registered by the use of a bias-extension test and a digital image correlation (DIC) equipment. To measure the interlaminar (between the layers) friction in the prepreg/prepreg interface a specialized rig is designed and built. The two tested materials are Cycom® HTA/977-2 from Cytec and HexPly® T700/M21 from Hexel, which are examples of the second and third generation of carbon fibre/epoxy prepreg. Where M21 includes craze stoppers in form of thermoplastic particles, the 977-2 has the same function but in melted stage. These particles seem to influence both the intraply deformation modes and increase the level of friction between layers. The results from the bias-extension test was compared with the theory of pin-jointed net (PJN) and it was found that M21 behaves accordingly. The measured rotation for 977-2 is less than the theoretical, this due to slippage. The rate of deformation seems to have an influence not only on the load level, but also in the mode of deformation. Both for the interlaminar and intraply deformation the resistance to motion were much larger for M21 than 977-2. / KEKS (kostnadseffektiva kompositer)

As the demand for control in modern vehicles grows, models are needed to develop a better understanding of processes and engine behavior. The thesis contributes with a generic extended MVEM with SI and CI as well as VVA compatibility and modeling structure using MATLAB/Simulink environment.  The model contains the engine components air filter, compressor with bypass valve, intercooler, throttle, intake manifold, cylinder, exhaust manifold, EGR, turbine with a wastegate, and exhaust system, keeping track of pressures, mass flows, temperatures, and oxygen concentrations.  This thesis presents models, parametrization, and signals that needed to be measured to make it possible to parametrize other engines with the same method. A 6-cylinder 12.7 liter Scania diesel engine and a 4-cylinder 2 liter Volvo petrol engine are used to validate the model. The model shows agreement with measured data for pressure, mass flow, temperature, and oxygen concentration on several operational points. That shows the model can handle most engines with just small adjustments. The component-based model structure also enables the possibility to change and adjust the models used by, for example using the extended ellipse model for compressor efficiency or implement a double Vibe function for combustion calculations. / Eftersom efterfrågan på reglering i moderna fordon växer behövs modeller för att utveckla bättre förståelse för processer och motorbeteende. Detta exjobb bidrar med en generisk utökad MVEM-motormodell med SI och CI samt VVA-kompatibilitet med modelleringsstruktur i MATLAB / Simulink-miljö.  Modellen innehåller motorns komponenter luftfilter, kompressor med bypassventil, intercooler, trottle, insugsgrenrör, cylinder, avgasgrenrör, EGR, turbin med wastegate och avgassystem.Modellen håller reda på tryck, massflöden, temperaturer och syrekoncentrationer.  I denna rapport presenteras modeller, parametrisering och de signaler som behöver mätas för att göra det möjligt att parametersätta andra motorer med samma metod. För att validera modellen används en 6-cylindrig 12,7 liters Scania-dieselmotor och en 4-cylindrig 2-liters Volvo bensinmotor. Modellen visar överensstämmelse med uppmätta data för tryck, massflöde, temperatur och syrekoncentration på flera driftpunkter. Det visar att modellen kan hantera de flesta motorer med enbart små justeringar. Den komponentbaserade modellstrukturen gör det också möjligt att ändra och justera de modeller som används till exempel med hjälp av den utökade elliptiska modellen för kompressoreffektivitet eller implementera en dubbel Vibe-funktion för förbränningsberäkningar.